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The Potential Effect of Climate Changes on Agriculture and Land Use
Abstract
Publisher Summary This chapter discusses the effects of possible greenhouse-gas induced changes of climate on agriculture and land use. The potentially most important changes of climate for agriculture upon which there is some agreement by general circulation models (GCMs) include changes in climatic extremes, warming in the high latitudes, poleward advance of monsoon rainfall, and reduced soil water availability. The chapter discusses several types of effects of climate change on agriculture such as the “direct” effects of elevated CO, shifts of thermal and moisture limits to cropping, effects on drought, heat stress and other extremes, effects on pests, weeds and diseases, and effects on soil fertility. Finally, the chapter presents a summary of overall effects on crop and livestock production. It can be concluded that while global levels of food production can probably be maintained in the face of climate change the cost of this could be substantial, and that significant geographic shifts of land use will occur.
... Climatic warming is most pronounced at high latitudes, with Alaska experiencing a temperature increase of about 0.3 1C per decade during summer and up to 2 1C per decade during winter in the last 30-40 years (Maxwell, 1997;Weller et al., 1999;Barber et al., 2000;Serreze et al., 2000). While plant production is constrained at high latitudes by a short growing season and low temperatures, the warming trend lengthens the growing season and reduces temperature constraints on high-latitude agriculture Parry, 1992). The northward intensification of agricultural, forestry and mining activities, which already resulted in increased population in Canada's mid-north and even in arctic areas (McCarthy et al., 2001), is possibly related to the temperature trend. ...
... Warming of 1.5-3.5 1C by the year 2030 and of 4-10 1C by the year 2100 is predicted for Alaska (Weller et al., 1999). Climate change is expected to further lengthen the frost-free season by 1-9 weeks (McCarthy et al., 2001), which might increase the competition for land in the region (Parry, 1992). Under such conditions, deforestation and agriculture can be increased by population growth or by better economic conditions independent of population size, such as improved infrastructure, profitability, technology and land holdings (Fitzsimmons, 2002). ...
Climate warming is most pronounced at high latitudes, which could result in the intensification of the extensively cultivated areas in the boreal zone and could further enhance rates of forest clearing in the coming decades. Using paired forest-field sampling and a chronosequence approach, we investigated the effect of conversion of boreal forest to agriculture on carbon (C) and nitrogen (N) dynamics in interior Alaska. Chronosequences showed large soil C losses during the first two decades following deforestation, with mean C stocks in agricultural soils being 44% or 8.3 kg m(-2) lower than C stocks in original forest soils. This suggests that soil C losses from land-use change in the boreal region may be greater than those in other biomes. Analyses of changes in stable C isotopes and in quality of soil organic matter showed that organic C was lost from soils by combustion of cleared forest material, decomposition of organic matter and possibly erosion. Chronosequences indicated an increase in C storage during later decades after forest clearing, with 60-year-old grassland showing net ecosystem C gain of 2.1 kg m(-2) over the original forest. This increase in C stock resulted probably from a combination of large C inputs from belowground biomass and low C losses due to a small original forest soil C stock and low tillage frequency. Reductions in soil N stocks caused by land-use change were smaller than reductions in C stocks (34% or 0.31 kg m(-2)), resulting in lower C/N ratios in field compared with forest mineral soils, despite the occasional incorporation of high-C forest-floor material into field soils. Carbon mineralization per unit of mineralized N was considerably higher in forests than in fields, which could indicate that decomposition rates are more sensitive in forest soils than in field soils to inorganic N addition (e.g. by increased N deposition from the atmosphere). If forest conversion to agriculture becomes more widespread in the boreal region, the resulting C losses (51% or 11.2 kg m(-2) at the ecosystem level in this study) will induce a positive feedback to climatic warming and additional land-use change. However, by selecting relatively C-poor soils and by implementing management practices that preserve C, losses of C from soils can be reduced.
... Three possible effects of climate change on vegetation have been identified so far. The first effect would be the stomata closure (Morison 1987;Cure and Acock 1986;Parry 1992). The second effect would be the increase in the production of biomass (Post et al. 1992) which may offset the decrease of transpiration due to stomata closure. ...
... The evapotranspiration from the vegetation has been reduced due to the closure of the stomata caused by the increase in carbon dioxide concentration by 30%. This value is in agreement with previous plant physiological studies (Cure and Acock 1986;Morison 1987;Parry 1992) and hydrological studies (Wigley and Jones 1985;Kite 1993). Also, the increased net ecosystem production was depicted in the increased tree covered area and the density of vegetation. ...
A hydrological modelling of the flood response of two watersheds to climate change are presented. The two study watersheds are the Upper Campbell and the Illecillewaet watersheds located in British Columbia. The first watershed is a maritime watershed located on the east slopes of the Vancouver Island mountains whereas the second watershed is located in the Selkirk Mountains in Eastern British Columbia. The Canadian Climate Centre General Circulation Model (CCC GCM) has been used for the estimation of the effect of the climate change on meteorological parameters. The CCC GCM is a steady state model and the output of the 1991 run has been used. In addition to the changes in the amounts of precipitation and temperature usually assumed in hydrological climate change studies, other meteorological and climatic parameters are also considered; specifically, the effect of climate on the spatial distribution of precipitation with elevation, and also on cloud cover, glaciers, vegetation distribution, vegetation biomass production, and plant physiology. The results showed that the mean annual temperature in the two watersheds could increase by more than 3°C and the annual basin-wide precipitation could increase by 7.5% in Upper Campbell watershed and by about 17% in the Illecillewaet watershed. As a result, the mean annual runoff will increase by 7.5% in the Upper Campbell watershed and 21% in the Illecillewaet basin. For the study of floods, nine flood parameters have been investigated, the total number of flood episodes, the flood days per year, the duration of flood events, the annual flood volume, the mean flood flow, the mean flood peak, the annual maximum flood peak, the day of occurrence of the centroid of flood volume, and the day of occurrence of annual maximum flood peak. These nine parameters were extracted from the hydrographs of the two study watersheds using the double long-term mean daily flow. The study showed that, under the climate change scenario, the floods in the maritime Upper Campbell watershed would increase, on average, in magnitude by 14%, in volume by 94%, in frequency by 11%, and duration by 44%. The timing of the floods would remain almost unchanged, and the centroid of flood volume would shift earlier by only 2 days. In contrast, in the interior mountain Illecillewaet watershed, the floods would decrease, on average, in magnitude by 7%, in volume by 38%, and frequency by 23%. The duration of flood events, under the altered climate scenario, would remain, essentially, unchanged increasingly by only 2.6%. Also, the study showed that in the Illecillewaet watershed the largest change between the altered climate and the present climate scenarios would be the timing of floods since the centroid of flood volume would occur 20 days earlier. The above changes in the flood response of the two study watersheds can be explained by the changes in the distribution and form of annual precipitation. These results indicate that different management procedures will be needed to minimize the effects of climate change on the flooding of the two climatically different watersheds and the regions that they represent.
... Climatic warming is most pronounced at high latitudes, with Alaska experiencing a temperature increase of about 0.3 1C per decade during summer and up to 2 1C per decade during winter in the last 30-40 years (Maxwell, 1997;Weller et al., 1999;Barber et al., 2000;Serreze et al., 2000). While plant production is constrained at high latitudes by a short growing season and low temperatures, the warming trend lengthens the growing season and reduces temperature constraints on high-latitude agriculture Parry, 1992). The northward intensification of agricultural, forestry and mining activities, which already resulted in increased population in Canada's mid-north and even in arctic areas (McCarthy et al., 2001), is possibly related to the temperature trend. ...
... Warming of 1.5-3.5 1C by the year 2030 and of 4-10 1C by the year 2100 is predicted for Alaska (Weller et al., 1999). Climate change is expected to further lengthen the frost-free season by 1-9 weeks (McCarthy et al., 2001), which might increase the competition for land in the region (Parry, 1992). Under such conditions, deforestation and agriculture can be increased by population growth or by better economic conditions independent of population size, such as improved infrastructure, profitability, technology and land holdings (Fitzsimmons, 2002). ...
Climate warming is most pronounced at high latitudes, which could result in the intensification of the extensively cultivated areas in the boreal zone and could further enhance rates of forest clearing in the coming decades. Using paired forest-field sampling and a chronosequence approach, we investigated the effect of conversion of boreal forest to agriculture on carbon (C) and nitrogen (N) dynamics in interior Alaska. Chronosequences showed large soil C losses during the first two decades following deforestation, with mean C stocks in agricultural soils being 44% or 8.3 kg m−2 lower than C stocks in original forest soils. This suggests that soil C losses from land-use change in the boreal region may be greater than those in other biomes. Analyses of changes in stable C isotopes and in quality of soil organic matter showed that organic C was lost from soils by combustion of cleared forest material, decomposition of organic matter and possibly erosion. Chronosequences indicated an increase in C storage during later decades after forest clearing, with 60-year-old grassland showing net ecosystem C gain of 2.1 kg m−2 over the original forest. This increase in C stock resulted probably from a combination of large C inputs from belowground biomass and low C losses due to a small original forest soil C stock and low tillage frequency. Reductions in soil N stocks caused by land-use change were smaller than reductions in C stocks (34% or 0.31 kg m−2), resulting in lower C/N ratios in field compared with forest mineral soils, despite the occasional incorporation of high-C forest-floor material into field soils. Carbon mineralization per unit of mineralized N was considerably higher in forests than in fields, which could indicate that decomposition rates are more sensitive in forest soils than in field soils to inorganic N addition (e.g. by increased N deposition from the atmosphere). If forest conversion to agriculture becomes more widespread in the boreal region, the resulting C losses (51% or 11.2 kg m−2 at the ecosystem level in this study) will induce a positive feedback to climatic warming and additional land-use change. However, by selecting relatively C-poor soils and by implementing management practices that preserve C, losses of C from soils can be reduced.
... Plant production and microbial activity are constrained at high latitudes by low temperatures and a short growing season Parry 1992). Temperature increases of about 0.3°C per decade during summer and up to 2°C per decade during winter have occurred during the last 30-40 years in Alaska (Maxwell 1997;ARAG-USGCRP 1999;Barber et al. 2000;Serreze et al. 2000). ...
... Warming might also make conditions more favorable for agriculture at high latitudes by lengthening the growing season (Myneni et al. 1997) and reducing frost probability. Together with increased competition for land (Parry 1992), disturbances associated with warming might accelerate the conversion of forest to other land-surface types. ...
Land-use change is likely to be a major component of global change at high latitudes, poten-tially causing significant alterations in soil C and N cycling. We addressed the biogeochemical impacts of land-use change in fully replicated black spruce forests and agricultural fields of different ages (fol-lowing deforestation) and under different management regimes in interior Alaska. Change from forests to cultivated fields increased summer temperatures in surface soil layers by 4–5 °C, and lengthened the season of biological activity by two to three weeks. Decomposition of a common substrate (oat stubble) was enhanced by 25% in fields compared to forests after litter bags were buried for one year. In-situ net N mineralization rates in site-specific soil were similar in forests and fields during summer, but during winter, forests were the only sites where net N immobilization occurred. Field age and management had a significant impact on C and N mineralization. Rates of annual decomposition, soil respiration and summer net N mineralization tended to be lower in young than in old fields and higher in fallow than in planted young fields. To identify the major environmental factors controlling C and N mineralization, soil temperature, moisture and N availability were studied. Decomposition and net N mineralization seemed to be mainly driven by availability of inorganic N. Soil temperature played a role only when comparing forests and fields, but not in field-to-field differences. Results from soil respiration measure-ments in fields confirmed low sensitivity of heterotrophic respiration, and thus decomposition to tem-perature. In addition, both soil respiration and net N mineralization were limited by low soil water con-tents. Our study showed that (1) C and N mineralization are enhanced by forest clearing in subarctic soils, and (2) N availability is more important than soil temperature in controling C and N mineraliza-tion following forest clearing. Projecting the biogeochemical impacts of land-use change at high lati-tudes requires an improved understanding of its interactions with other factors of global change, such as changing climate and N deposition.
... The emissions associated with fossil fuel combustion have profound implications for climate change (Kumar et al. 2022), affecting weather patterns (Singh et al. 2023;Badrzadeh et al. 2022), crop yields, and overall environmental health (Hatfield and Prueger 2015;Parry 1992;Pariyar et al. 2020;Shestakova et al. 2020). Recognizing this, many countries have implemented energy efficiency measures as a strategy for both energy security and GHG mitigation (Haines 2017). ...
Air conditioning in buildings is a significant contributor to electricity demand in developing countries and is expected to increase significantly in the coming years. This increase will lead to higher greenhouse gas (GHG) emissions, air pollution, and related impacts. In India, the energy use due to room air conditioners (RACs) is estimated to cause 18%, 9%, and 8% of fine particulate matter (PM2.5), nitrogen oxides (NOx), and sulphur dioxide (SO2) emissions, respectively. These emissions contribute to 5% of power sector PM2.5 concentrations in India and were attributable to 5748 air pollution-related deaths in 2017. If no technological improvements are made, India’s RAC energy demand is expected to increase from 56 Gigawatt (GW) in 2017 to 289 GW in 2046, attributable to 39,072 deaths annually by 2046. However, implementing the Indian Cooling Action Plan (ICAP) could reduce RAC demand and associated pollution by 60%. Stricter standards for coal-based power plants, in accordance with National Clean Air Programme (NCAP), could also reduce air pollution from RACs by 50%. An integrated approach including ICAP, NCAP, and Intended Nationally Determined Contributions (INDCs) could lead to a compounded overall reduction of 84% in PM2.5 concentrations from RACs, with 33,047 lives saved annually in 2046.
... Variations in temperature and humidity strongly disturb the herbivorous insect life cycle, their physiology, and geographical distribution, as well as changing the host plant (Shukla et al. 2019). For example, it was reported that many insect pest species have expanded their geographic ranges from tropical habitats at lower altitudes to temperate regions at higher altitudes (Parry 1992;Rosenzweig et al. 2001;Parmesan, Yohe 2003;Bale, Hayward 2010). ...
... These factors can limit reproductive success of plants by damaging their generative organs, causing reduced fitness and increased mortality, which is better documented in trees (Doležal et al., 2010;Klisz et al., 2022;Sangüesa-Barreda et al., 2021;Zohner et al., 2020). Moreover, climate change will also cause alterations in the deposition and circulation of elements and water availability, affecting the soil's physical and chemical properties and land use changes (Brouyère et al., 2004;Greaver et al., 2016;Parry, 1992). However, it is still impossible to include the potential distribution of notable differences in the preferences of the studied species to local habitat conditions in the models due to the lack of available highresolution soil and hydrological variables, as well as land use maps with projections of their future changes. ...
Many phenological studies have shown that spring geophytes are very sensitive to climate change, responding by shifting flowering and fruiting dates. However, there is a gap in knowledge about climatic drivers of their distributions and range shifts under climate change. Here we aimed to estimate climate niche shifts for four widely distributed and common geophytes of the nemoral zone of Europe (Anemone nemorosa, Anemone ranunculoides, Convallaria majalis and Maianthemum bifolium) and to assess the threat level under various climate change scenarios. Using MaxEnt species distribution models and future climate change scenarios we found that the precipitation of the warmest quarter was the most important factor shaping their ranges. All species studied will experience more loss in the 2061–2080 period than in 2041–2060, and under more pessimistic scenarios. M. bifolium will experience the highest loss, followed by A. nemorosa, A. ranunculoides, and the smallest for C. majalis. A. ranunculoides will gain the most, while M. bifolium will have the smallest potential range expansion. Studied species may respond differently to climate change despite similar current distributions and climatic variables affecting their potential distribution. Even slight differences in climatic niches could reduce the overlap of future ranges compared to present. We expect that due to high dependence on the warmest quarter precipitation, summer droughts in the future may be particularly severe for species that prefer moist soils. The lack of adaptation to long-distance migration and limited availability of appropriate soils may limit their migration and lead to a decline in biodiversity and changes in European forests.
... Currently, agriculture is facing severe challenges such as increasing land degradation [3], postharvest losses [4], the harmful effects of agrochemicals on the ecosystems on farms (and on human health) [5], water scarcity [6], the increasing cost of energy and fertilizer [7], and the effects of climate fluctuations and change on agriculture [8]. These challenges result in a decrease in yields, although food production costs keep increasing. ...
Agricultural productivity depends primarily on energy, water, and land resources, which are increasingly becoming more scarce and expensive. Electricity generation with photovoltaic (PV) solar energy technology requires significant amounts of space, especially in densely populated countries, generating a societal debate about allocating land (that may have alternative uses) for deploying PV systems. Rather than dedicating vast amounts of agricultural land to be used as solar farms, PV systems are deployed in agricultural lands so that a given piece of land can be used for agriculture and energy generation (the so-called agrivoltaics). A framework based on systems thinking is essential for the design and operation of smart, sustainable agrivoltaics systems to meet the design goals or to satisfy the expectation of all stakeholders (farmers, energy developers, policymakers, and local community members that may be impacted). In this paper, we propose a system-based conceptual and design framework for smart, sustainable agrivoltaics. We also discuss the benefits of agrivoltaics and the challenges to their adoption.
... Canada have historically been affected by droughts, periods of excess water, pests, cold and warm spells, and these regions are projected to continue to be increasingly affected by climate change-driven cropstressors depending on location (He et al., 2018;Parry, 1992). Under a warming climate, the spatial extent of areas thermally suitable for intensive crop production is likely to expand dramatically northwards across Nordic countries (King et al., 2018), including Canada ( Figure 3). ...
Large‐scale, intensive agriculture is a critical activity to support global food production, yet it has taken a significant toll on the equally critical ecosystem services supplied by global biodiversity. This is particularly true for the planet’s most threatened ecosystems: freshwaters. As one of the world’s largest agricultural producers, Canada is also home to much of the world’s freshwater. As Canada’s agricultural capacity expands under climate warming into more northerly latitudes—and in some cases regions with large carbon sinks—it is imperative that this sectoral shift is accompanied by careful management to avoid exacerbating ecosystem service losses. Across Canada, agricultural practices vary in terms of their impact on freshwater ecosystems. Agricultural water extraction, storage behind dams, diversions, dredging, and clearing of riparian vegetation can impact more naturalized flow regimes. This review explores the influence of managed low flows on ecosystem functioning in man‐made drainage/ irrigation ditch systems. We examine how low flows in these systems can impact ecosystem functions in agricultural watersheds with fragmented natural capital. We provide management options to protect ecosystem functions under a changing climate, recognizing that in agro‐ecosystems, drainage/irrigation ditch systems provide a critical remnant habitat to support biodiversity in otherwise depauperate landscapes.
... Despite the lowest soil temperature the lower SOC stock in lower and upper alpines than temperate seemed to have occurred due to prevalence of snowfall for more than five months during the winter and early summer seasons. This probably induced prolonged physiological dry conditions that caused reduction in plant growth, litter production, microbial activity and development of soil organic carbon complex (Parry, 1992). Run off loss of SOC during the summer season, when snow melts and drains to down hill through slope might be the other reason for the lower SOC stock in the upper and lower alpines. ...
... The research reported here is part of a larger study articles (Cannell & Hooper, 1990;Parry, 1992; on the effects of climate change on plant growth, Kenny Harrison & Parry, 1993). Most previous viability, secondary metabolism and nutritive value research has focused on the outcome of varying one in the model forage legume Lotus cormculatus. ...
Five clonal plants of three genotypes of Lotus corniculatus were grown in each of eight controlled environments under combinations of two temperature regimes (18/10 °C and 25/15 °C), two CO2 concentrations (ambient and 700 ppmv) and two water applications (ad libitum or 60% draughted). Plants were harvested at full flower and measurements made of plant growth and development. Of the three environmental variables studied, higher growth temperatures resulted in the largest number of significant changes to the measured variables. Reproductive capacity, growth rate, shoot biomass, water use efficiency and chlorophyll content were all enhanced by raising the growth temperature from 18 to 25 °C. Doubling the CO2 concentration enhanced the growth rate, shoot biomass and water use efficiency and ameliorated some of the effects of drought, including reproductive capacity, and biomass production, but reduced flowering time, specific leaf area, and chlorophyll content of both droughted and undroughted plants. Drought alone reduced reproductive capacity, growth rate and above ground biomass but significantly increased root biomass in all environments. The agronomic effects resulting from a combined increase in growth temperature, doubled CO2 concentration and mild drought in this experiment were a shorter vegetative period and an increase in biomass, but a fall in reproductive capacity.
... Despite the lowest soil temperature the lower SOC stock in lower and upper alpines than temperate seemed to have occurred due to prevalence of snowfall for more than five months during the winter and early summer seasons. This probably induced prolonged physiological dry conditions that caused reduction in plant growth, litter production, microbial activity and development of soil organic carbon complex (Parry, 1992). Run off loss of SOC during the summer season, when snow melts and drains to down hill through slope might be the other reason for the lower SOC stock in the upper and lower alpines. ...
Soils are the third biggest sink of carbon on the earth. Hence, suitable land uses for a climatic condition are expected to sequester optimum atmospheric carbon in soils. But, information on how climatic conditions and land uses influence carbon accumulation in the soils on the Himalayan Mountains is not known. This study reports the impact of four climatic conditions (sub-tropical, altitude: 500–1200m; temperate 1200–2000m; lower alpine 2000–3000m; upper alpine, 3000–3500m) and four land uses (forest, grassland, horticulture, agriculture) on the concentrations and stocks of soil organic carbon (SOC) in upper (0–30cm) and deeper (30–100cm) soil depths on the western Himalayan Mountains of India. The study also explored the drivers which influenced the SOC stock build up on the mountains. Rainfall and soil moisture showed quadratic relations, whereas temperature declined linearly with the altitude. SOC stock as well as concentration was the highest (101.8Mgha−1 in 0–30cm, 227.97Mgha−1 in 0–100cm) in temperate and the lowest in sub-tropical climate (37Mgha−1 in 0–30cm, 107.04Mgha−1 in 0–100cm). Pattern of SOC stock build up across the altitude was: temperate>lower alpine>upper alpine>sub-tropical. SOC stocks in all land uses across the climatic conditions, except agriculture in lower alpine, was higher (0.7 to 41.6%) in the deeper than upper soil depth. SOC stocks in both the depths showed quadratic relations with soil temperature and soil moisture. Other factors like fine soil particles, land-use factor and altitude influenced positively whereas slope and pH, negatively to the SOC stocks. In all climatic conditions, other than temperate, SOC stocks were greater in natural ecosystems like forests and pastures (112.5 to 247.5Mgha−1) than agriculture (63 to 120.4Mgha−1). In temperate climate, SOC stock in agriculture (253.6Mgha−1) on well formed terraces was a little higher than forest (231.3Mgha−1) on natural slope. These observations, suggest that land uses on temperate climate may be treated as potential sinks for sequestration of the atmospheric carbon. However, agriculture in subtropical climate need to be pursued with due SOC protection measures like the temperate climate for greater sequestration of the atmospheric carbon.
... Water availability in Mediterranean regions is likely to be altered by the increase in atmospheric carbon dioxide and related climate changes. Predictions have been made that as CO2 supply to plants increases, their water supply may decrease (Parry 1992). Therefore, a proper understanding of the response mechanisms of trees to water shortage is a prerequisite for making predictions on the impact of climate change on the Mediterranean forests. ...
The present study was carried out to elucidate the response mechanisms of 50-year-old Pinus halepensis Mill. trees to a long-term and severe drought. The amount of water available to trees was artificially restricted for 12 months by covering the soil with a plastic roof. Over the short term a direct and rapid impact of drought was evident on the water relations and gas exchanges of trees: as the soil dried out in the Spring, there was a concurrent decrease of predawn water potential; transpiration was strongly reduced by stomatal closure. Seasonal changes in the water volume fractions of twig and stem xylem were observed and interpreted as the result of cavitation and refilling in the xylem. When droughted trees recovered to a more favourable water status, refilling of embolized xylem was observed; twig predawn water potentials were still negative in the period when the embolism was reversed in the twig xylem. A few months after the removal of the covering, no differences in whole plant hydraulic resistance were observed between droughted and control trees. Needle and shoot elongation and stem radial growth were considerably reduced in droughted trees; no strategy of trees to allocate carbon preferentially to the stem conducting tissues was apparent throughout the experiment. An after-effect of the drought on growth was observed.
... Los cambios de uso del territorio, tanto de tipo como de intensidad, están considerados como el factor con mayor impacto actual sobre la biodiversidad en general y la de los ecosistemas mediterráneos en particular (Sala et al. 2000). Este hecho, que dificulta en gran medida la detección e interpretación de los efectos atribuibles estrictamente al cambio climático, se complicará en el futuro porque el cambio climático comportará nuevas modificaciones en las distribuciones y tipos de usos (Parry 1992), con tendencias hacia el abandono de la agricultura y de la ganadería en los territorios cuyas condiciones climáticas devengan adversas, desplazamiento de estos usos hacia nuevos territorios de clima favorable, expansión de las modalidades de uso intensivo como forma de paliar las fluctuaciones climáticas, cambios en las explotaciones forestales, crisis de ciertos sistemas tradicionales de usos del territorio, nuevas localizaciones urbanas y de infraestructuras, etc. La distribución de usos determina otros factores como la fragmentación de los paisajes (Tellería y Santos 2001), que condicionarán y limitarán las posibilidades de migración de las especies. Además, las características del régimen de incendios están estrechamente relacionadas con la configuración del paisaje y de los combustibles, y por lo tanto con los usos del territorio. ...
... Los cambios de uso del territorio, tanto de tipo como de intensidad, están considerados como el factor con mayor impacto actual sobre la biodiversidad en general y la de los ecosistemas mediterráneos en particular (Sala et al. 2000). Este hecho, que dificulta en gran medida la detección e interpretación de los efectos atribuibles estrictamente al cambio climático, se complicará en el futuro porque el cambio climático comportará nuevas modificaciones en las distribuciones y tipos de usos (Parry 1992), con tendencias hacia el abandono de la agricultura y de la ganadería en los territorios cuyas condiciones climáticas devengan adversas, desplazamiento de estos usos hacia nuevos territorios de clima favorable, expansión de las modalidades de uso intensivo como forma de paliar las fluctuaciones climáticas, cambios en las explotaciones forestales, crisis de ciertos sistemas tradicionales de usos del territorio, nuevas localizaciones urbanas y de infraestructuras, etc. La distribución de usos determina otros factores como la fragmentación de los paisajes (Tellería y Santos 2001), que condicionarán y limitarán las posibilidades de migración de las especies. Además, las características del régimen de incendios están estrechamente relacionadas con la configuración del paisaje y de los combustibles, y por lo tanto con los usos del territorio. ...
... During the last few years much attention has been paid to potential effects of CO 2 -mediated changes in plant chemical and physical traits (Parry, 1992; Bazin et al., 2002). However, only in few cases have clear quantitative effects of enhanced CO 2 on multiple plant traits, variation of plant responses depending on developmental stage, and consequences of CO 2 mediated changes of plant traits on natural herbivores been demonstrated (e.g. ...
1. Concentration of atmospheric CO2 is predicted to double during the 21st century. However, quantitative effects of increased CO2 levels on natural herbivore–plant interactions are still little understood.
2. In this study, we assess whether increased CO2 quantitatively affects multiple defensive and nutritive traits in different leaf stages of cyanogenic wildtype lima bean plants (Phaseolus lunatus), and whether plant responses influence performance and choice behaviour of a natural insect herbivore, the Mexican bean beetle (Epilachna varivestis).
3. We cultivated lima bean plants in climate chambers at ambient, 500, 700, and 1000 ppm CO2 and analysed cyanogenic precursor concentration (nitrogen-based defence), total phenolics (carbon-based defence), leaf mass per area (LMA; physical defence), and soluble proteins (nutritive parameter) of three defined leaf age groups.
4. In young leaves, cyanide concentration was the only parameter that quantitatively decreased in response to CO2 treatments. In intermediate and mature leaves, cyanide and protein concentrations decreased while total phenolics and LMA increased.
5. Depending on leaf stage, CO2-mediated changes in leaf traits significantly affected larval performance and choice behaviour of adult beetles. We observed a complete shift from highest herbivore damage in mature leaves under natural CO2 to highest damage of young leaves under elevated CO2. Our study shows that leaf stage is an essential factor when considering CO2-mediated changes of plant defences against herbivores. Since in the long run preferred consumption of young leaves can strongly affect plant fitness, variable effects of elevated CO2 on different leaf stages should receive highlighted attention in future research.
... The research reported here is part of a larger study articles (Cannell & Hooper, 1990;Parry, 1992; on the effects of climate change on plant growth, Kenny Harrison & Parry, 1993). Most previous viability, secondary metabolism and nutritive value research has focused on the outcome of varying one in the model forage legume Lotus cormculatus. ...
Five clonal plants of three genotypes of Lotus corniculatus were grown in each of eight controlled environments under combinations of two temperature regimes (18/10 °C and 25/15 °C), two CO2 concentrations (ambient and 700 ppmv) and two water applications (ad libitum or 60% draughted). Plants were harvested at full flower and measurements made of plant growth and development. Of the three environmental variables studied, higher growth temperatures resulted in the largest number of significant changes to the measured variables. Reproductive capacity, growth rate, shoot biomass, water use efficiency and chlorophyll content were all enhanced by raising the growth temperature from 18 to 25 °C. Doubling the CO2 concentration enhanced the growth rate, shoot biomass and water use efficiency and ameliorated some of the effects of drought, including reproductive capacity, and biomass production, but reduced flowering time, specific leaf area, and chlorophyll content of both droughted and undroughted plants. Drought alone reduced reproductive capacity, growth rate and above ground biomass but significantly increased root biomass in all environments. The agronomic effects resulting from a combined increase in growth temperature, doubled CO2 concentration and mild drought in this experiment were a shorter vegetative period and an increase in biomass, but a fall in reproductive capacity.
... 2004). Major consequences for agricultural production (Parry 1992; Rosenzweig & Hillel 1998; Kriticos et al . 2003), forestry (Schwartz 1992), plant community composition (Buckland et al . ...
Calyptrate flies include numerous species that are disease vectors and have a high nuisance value, notably Musca domestica . Populations are often associated with livestock farms and domestic waste disposal facilities such as landfill, where the accumulating organic matter provides suitable breeding conditions for a range of species.
We examined the relationship between fly numbers and weather conditions using a 4‐year data set of weekly fly catches from six sites in southern UK, together with meteorological data. The first 3 years were used to develop predictive models, and these were then used to forecast fly populations in the fourth year. The accuracy of these predictions was assessed by comparison with the actual fly catches for that year. Separate models were developed for M. domestica , Calliphora spp. and all calyptrate flies combined.
Predictions based only on humidity, temperature and rainfall were strongly correlated with observed data ( r ² values ranged from 0·52 to 0·84), suggesting that fly population changes are largely driven by the weather rather than by biotic factors. We can forecast fly populations so that control measures need only be deployed when weather conditions are suitable for a fly outbreak, reducing the need for prophylactic insecticide use.
Climate change was simulated using the most recent predictions of future temperature increases. Our models predicted substantial increases in fly populations up to 244% by 2080 compared with current levels, with the greatest increases occurring in the summer months.
Synthesis and applications. Models developed use weather data to predict populations of pestiferous flies such as M. domestica , which may prove valuable in integrated control programmes. These models predict substantial increases in fly populations in the future under likely scenarios of climate change. If this occurs we may expect considerable increases in the incidence of fly‐borne disease.
... Changes in climate due to global CO 2 enrichment may influence agricultural crop yields and crop species utilised (Parry 1992). For example, simulation models suggest that elevation of CO 2 levels and associated climate change might affect crop NPP negatively in some regions (e.g. ...
In this article, we evaluate how global environmental change may affect microfood-webs and trophic interactions in the soil, and the implications of this at the ecosystem level. First we outline how bottom-up (resource control) and top-down (predation-control) forces regulate food-web components. Food-web components can respond either positively or negatively to shifts in NPP resulting from global change, thus creating difficulties in developing general principles about the response of soil biota to global change phenomena. We also demonstrate that top-down effects can be important in soil food-webs, creating negative feed-backs which may partially counter bottom-up effects. Secondly, we determine how soil food-webs and the processes they regulate respond to various global change phenomena. Enhanced atmospheric CO2 levels can have two main effects on plants which are relevant for the soil food-web, i.e. enhanced NPP (often positive) and diminished organic matter quality (with negative effects, at least in the short term). Climate change effects resulting from elevated CO2 levels may be mainly secondary through alteration of vegetation, as shown by examples. Intensification of land management is usually associated with greater disturbance, which alters soil food-web composition and key processes; this is particularly apparent in comparisons of conventionally tilled and nontilled agroecosystems. Global change involves shifts in plant species composition and diversity, possibly affecting soil food-webs; we interpret this in terms of theories relating biodiversity to ecosystem function. We conclude that a more detailed understanding of interactions between NPP, soil organic matter and components of the soil food-web, as well as their regulation of biogeochemical processes and ultimately ecosystem-level properties, is essential in better understanding long-term aspects of global change phenomena.
... The past two decades have seen precipitation in Britain increase in winter and decrease in summer (Marsh 1996;Conway 1998), with four droughts during the past 25 years of a severity that would be expected only once in 200 years or more (Price 1998). Considerable uncertainty is associated with projected future changes in precipitation (Parry 1992) but there are indications that the intensity and frequency of droughts will increase across south-east Britain (CCIRG 1996), most of western Europe (Arnell 1999) and other regions such as eastern Aus-tralia (Kothavala 1999) and Canada (Fleming & Candau 1998). So far, understanding of the likely ecological consequences is limited. ...
1. Information is lacking on how possible future changes in the seasonal occurrence and intensity of precipitation in Europe will affect the arthropod community of arable farmland.
2. We used a novel experimental approach to investigate the responses of farmland arthropods to spring precipitation in a spring-sown legume. Replicated plots were subjected to spring drought (plots shielded from rainfall), actual rainfall (reference) and spring irrigation. Shielding plots extended an existing drought to 58 days.
3. The response of epigeic arthropods was investigated using principal components analysis (PCA) and principal response curves (PRC). Temporal changes in treatment effects at the community level were more clearly displayed by PRC than by PCA, while PRC improved the interpretation of individual species' responses. PRC analysis has potential for wider application in ecological experiments and monitoring.
4. Short-term manipulation of precipitation in May affected the arthropod community for at least 97 days, despite exceptionally high rainfall in June. The effects of drought on the abundance of herbivores, mycophages, omnivores and predators were negative, while those of irrigation were positive. There were no differences in the responses of beneficial and pest taxa.
5. In addition to their intrinsic importance, these findings illustrate that spring weather might affect the availability of arthropod prey for insectivorous wildlife. Food availability has been implicated in the population declines of several insectivorous farmland birds.
6. The difficulty of manipulating rainfall in a temperate climate precludes realistic field studies of how farmland arthropods respond to precipitation. We suggest that automated rain shielding of experimental plots provides a technique for wider application in drought studies.
Entomopathogenic nematodes (EPNs) in the genera Steinernema and Heterorhabditis with their associated bacteria, Xenorhabdus spp. and Photorhabdus spp., are lethal parasites of different life stages of various insects, especially soil dwelling one. They inhabit most terrestrial habitats. From a historical perspective, studies on insect pathogenic nematodes in Iran were started in the late 1990s, when first attempts were done for isolation and identification of these entomopathogens. Herein, we provide a short overview of selected literature about the Iranian fauna of entomopathogenic and entomoparasitic nematodes and their application in laboratory, greenhouse and field. We discussed the possible contribution, challenges, and opportunity of these natural enemies for application in biological control of insect pest in IPM program.
The concept of Climate Smart Agriculture couples climate change and food security through the integration of adaptation and mitigation measures, mostly driven by smart-innovations. The paper is an attempt to present how climate smart agriculture concept could be driven by diffusion of the smart innovations in agriculture, and how these innovations could contribute to reduce vulnerability and hence increase resilience to climate change. The results of foresight studies shows that use of innovative technologies could provide benefits through reducing the asymmetry of information coming from natural production systems and through reducing its vulnerability, as well as reducing the environmental pressure and connected with this risk of increased production failures and negative external effects.
The results of the vulnerability assessments for Mongolia show that climate change could have a significant impact, in particular on the agricultural, forestry, and water resources sectors. These findings suggest that rising temperatures and reduced precipitation in some regions could increase the amount of arid and semi-arid areas, resulting in increased yields of forage crops and reduced or unchanged yields of grain and seed crops. The severity and frequency of drought may increase in the Gobi Desert area with climate change. This could lead to a greater use of drought-tolerant crops, increased irrigation, or changes in agricultural activity. A warmer climate may also lead to some expansion of agricultural lands, but the nation’s soil types would limit expansion. Mongolia’s natural zones (life zones) were established using a Holdridge Life Zone Classification Model simulation and the 2×CO2 climate change scenarios. According to these scenarios, the steppe zone’s characteristics will undergo significant change and the zone’s boundaries will be shifted. The water resources assessment showed that basin runoff is much more sensitive to temperature and precipitation for the rivers in the northwestern (desert) part of the country than other regions and relatively more sensitive in the steppe region than the mountainous region.
The potential water balance in the Valley of Niari (1974-1991) reveal an important seasonal loss of hydrous flow during the season of the rainy minimum. In the extreme cases, its duration can reach one year, thus underlining the character slightly wet of this enclave in the wet environment of central Africa.
The characteristics of the current tendency toward climate change in Mongolia and the doubling of carbon dioxide (CO2) levels (referred to as 2XCO2) scenario from the General Circulation Model (GCM) are briefly described. The effect of climate change on the production of spring wheat in Mongolia, given the nation’s geographic and climatic conditions, was assessed. In general, the yield decreased 19–67% under the GCM-based 2XCO2 scenario. This scenario assumed that growing season temperatures and precipitation would increase, but that potential evapotranspiration would be higher. However, wheat yields for the actual climate change trend (i.e., reduced temperature during the growing season and increased precipitation) increased 10.4–70.2% at six of seven locations. Simulated adaptive measures, such as changing planting dates, using different varieties of spring wheat, and applying the ideal amount of nitrogen fertilizer at the optimum time, are potential responses that could modify the effects of climate change on wheat production.
Olive culture is growing rapidly, and expanding all over the world outside traditional centres of olive growth and production. Olives are not only a significant food source, but also contribute to human health and are becoming popular in health-conscious diets far beyond their Mediterranean origins. Reviewing an extensive array of literature from both a theoretical and practical perspective, this comprehensive guide deals with all aspects of olive culture, from its history, origins and traditional techniques to the latest horticultural procedures and basic physiology. The book's accessible and broadly illustrated format makes it an indispensable text for students, interested individuals and both active and amateur horticulturists.
The 110 million people who live in the low-lying deltaic country of Bangladesh are highly dependent upon an agricultural system that is finely attuned to a tropical monsoon climate and associated water regime. Any significant change in the climate and water regimes of Bangladesh is likely to have profound effects on biological resources. This in turn could have serious effects on the socio-economic systems of the country (see Chapter 5). Here, the effects of climate and sea-level changes on the hydrological and biological resources of Bangladesh are explored through four main questions: What is the current resource setting of Bangladesh? How might the water resources be affected by climate warming? How might crop agriculture be affected? How might other bio-resources be affected by changing climate and water regimes? The final section of this chapter draws conclusions from this review and identifies follow-up actions that could be taken in response to the question: What needs to be done?
Farmer perceptions clearly influence the adoption of technology and adaptation to climate change, but may not be consistent with or captured by scientific measurements. There has been a significant research on how perceptions influence water resource management and adaptation to climate, but conclusions are unclear or contradictory. This research aimed to clarify what shapes perceptions and how this understanding can refine meteorological data collection and to make more relevant and useful tools for farmers to adapt to changes in the water cycle. A survey of 244 small‐scale maize farmers was conducted using a questionnaire and semi‐structured interviews in two districts in southern and western Kenya which differed in climate type and farming systems. Farmer perceptions of and adaptation to climate uncertainty were investigated and compared with meteorological data. Most farmers perceived changes in the patterns of rainfall and dry spells, including later onset of rains than in the past. They have already adjusted their management based on these perceptions, including later planting times. Despite this, analysis of meteorological data indicated no major trends in rainfall or dry spell patterns in the two regions. This research confirms that the perception that the water cycle is changing is based on a combination of climatic, economic, or social observations, and farmers are already changing their management to adapt to the perceived changes in climate. The article explores the reasons why these perceptions were inconsistent with the available meteorological data and suggests that research may improve the usefulness of meteorological data to farmers. WIREs Water 2016, 3:105–125. doi: 10.1002/wat2.1118
This article is categorized under: Human Water > Water as Imagined and Represented
In this study, we conducted growth chamber experiments using three types of soil (wetland, rice paddy, and forest) under the conditions of a severe increase in the temperature and N-deposition in order to investigate how extreme weather influences the characteristics of the dissolved organic matter (DOM) leaching from different soil types. This leachate controls the quantity and quality of DOM in surface water systems. After 5 months of incubation, the dissolved organic carbon (DOC) concentrations decreased in the range of 21.1 to 88.9 %, while the specific UV absorption (SUVA) values increased substantially in the range of 19.9 to 319.9 % for all of the samples. Higher increases in the SUVA values were observed at higher temperatures, whereas the opposite trend was observed for samples with N-addition. The parallel factor analysis (PARAFAC) results showed that four fluorescence components: terrestrial humic-like (component 1 (C1)), microbial humic-like (component 2 (C2)), protein-like (component 3 (C3)), and anthropogenic humic-like (component 4 (C4)) constituted the fluorescence matrices of soil samples. During the experiment, labile DOM from the soils was consumed and transformed into resistant aromatic carbon structures and less biodegradable components via microbial processes. The principle component analysis (PCA) results indicated that severe temperatures and N-deposition could enhance the contribution of the aromatic carbon compounds and humic-like components in the soil samples.
1. Simulated late frost was applied to five herbaceous plant communities in Derbyshire, UK. The results establish a clear positive relationship between the frost resistance of the above-ground biomass and independently published estimates of genome size. 2. Previous studies have established that in small genome species the dependence of growth upon current cell divisions dictates that development is delayed until warmer summer conditions. As a result of this, we suggest that selection pressures promoting frost tolerance will have been less pronounced in these species and that in temperate climates their potential responsiveness to global warming could be curtailed by the continued occurrence of late-frost events.
Cabbage, Brassica oleracea subsp. capitata (cv. Lennox and Rinda), and oilseed rape, Brassica
rapa subsp. oleifera (cv. Valo and Tuli), plants were grown under ambient CO2 (360 ppm) or elevated CO2 (720 ppm) at 23/18 °C and under a photoperiod of 22/2 h light (250 ímol m-2 s-1)/dark regime for up to 5 weeks. Afterward, the performance of the crucifer specialist Plutella xylostella (Lepidoptera: Plutellidae) and the generalist Spodoptera littoralis (Lepidoptera: Noctuidae) on those plants was studied. The mean relative growth rate (RGR) of P. xylostella larvae, feeding on both cultivars of oilseed rape or on the Lennox cultivar of cabbage leaves grown at an elevated CO2 concentration, was significantly reduced as compared to ambient CO2. A negative larval growth rate at elevated CO2 was observed for P. xylostella on both oilseed rape cultivars, but the growth rate was reduced but positive on cabbage. Conversely, the RGR of S. littoralis on either plant species was not affected by CO2 treatment but was lower on cabbage cv. Rinda than on cv. Lennox. The mortality of the larvae was not affected by CO2 treatment either. At the same time, elevated CO2 significantly decreased the concentrations of leaf phytochemical constituents in oilseed rape, i.e., total phenolics and total nitrogen, but not in cabbage. The effect of elevated CO2 on the leaf glucosinolate concentrations of both plant species was marginal. In addition, the observed significant changes in individual glucosinolate concentrations of oilseed rape leaves were not consistent among cultivars. However, our results demonstrate for the first time quite strong effects of CO2 enrichment on the larval performance of P. xylostella, which is an important pest of Brassica plants around the world. Further studies are still required to increase our understanding of why elevated CO2 differently affects the performance of specialist and generalist insect herbivores on Brassica plants.
The potential effects of global warming on the occurrence of four types of Japanese pest insects were studied by developing a computer program. The number of generations of each insect under present thermal condition and after 2℃ warming at 960 locations in Japan where temperature data was measured by the AMeDAS system was estimated. Thermal summation and daylength models were used to describe insect development and deleterious effects of low and high temperatures on the insects. In most regions, a non-diapausing insect, Plutella xylostella would complete two additional generations compared to the present. In a winter diapausing insect, Chilo suppressalis, the northern boundaries of zones of two and three generations would shift north-ward by about 300 km. A cold weather susceptible insect, Tribolium confusum, would expand its distribution area northward, but the northern front of its distribution would not shift markedly, except for in the central mountainous regions of the Main Island. Ephestia kuhniella, which is susceptible to hot weather, would not be able to occur in the western part of the Main Island and Shikoku and Kyushu Islands due to high temperatures in summer, leading to a large shrinkage in its distribution area in Japan. Our results demonstrated that the effects of global warming on insect occurrence would be significant, but should vary depending on the biological characters of the insects.
The effects of elevated atmospheric CO2 concentration on the partitioning of dry matter and recent assimilate was investigated for three plant species (rye grass, wheat and Bermuda grass). This was evaluated in plant-soil microcosm systems maintained at specific growth conditions, under two CO2 regimes (450 and 720 μmol mol−1). The distribution of recent assimilate between plant, microbial and soil pools was determined by 14CO2 pulse chase, for each plant species at both CO2 concentrations. Growth of rye grass and wheat (both C3) was ca. doubled at the higher CO2 concentration. Dry matter partitioning was also significantly affected, with an increased root-to-shoot ratio for wheat (0.72–1.03), and a decreased root-to-shoot ratio for rye grass (0.68-0.47) at elevated CO2. For Bermuda grass (C4), growth and partitioning of dry matter and 14C were not affected by CO2 concentration. 14C-allocation to the rhizospheres of rye-grass and wheat was found to be increased by 62 and 19%, respectively, at the higher CO2 concentration. The partitioning of 14C within the rhizospheres of the two C3 species was also found to be affected by CO2 concentration. At the higher CO2 concentration, proportionately less 14C was present in the microbial fraction, relative to that in the soil. This indicates altered microbial utilisation of root-released compounds at the higher CO2 concentration, which may be a consequence of altered quantity or quality of rhizodeposits derived from recent assimilate.
Soil organic carbon (SOC) density and soil microbial biomass carbon (SMBC) were studied in 0–30 and 0–100 cm depths in arable and non-arable lands under four soil moisture and temperature regimes (SMTR) [i.e., cryic-ardic (wet period 22°C)] and four soil erosion regimes (slight, moderate, severe, and very severe) in cold arid to subtropical conditions of Western Himalayas, India. The study revealed that SOC density (1.2 ± 0.2 kg m−2) was the lowest in ustic-hyperthermic and highest in udic-mesic (4.2 ± 0.8 kg m−2) and udic-thermic (4.2 ± 0.7 kg m−2) conditions. SOC density in aridic-cryic was higher in arable than in nonarable lands, whereas the trend was reverse in other soil moisture and temperature regimes. Spatial variability of SOC was higher in nonarable than arable lands. Across SMTR and land uses, both SOC density and SMBC were significantly higher on slightly to moderately than severely to very severely eroded surfaces. In 0–30 cm depth, SOC density was highest in Dystrudepts (17.6 kg m−2) and lowest in Hapludalfs (1.9 kg m−2), whereas in 0–100 cm depth, Dystrudepts (32 kg m−2) and Haplustepts (4.2 kg m−2) hold the highest and lowest SOC density, respectively. SMBC moved parallel to SOC density. Study claims that agriculture with good soil and water conservation measures has potential to sequester SOC on the hills.
Organic farming has increased in popularity in recent years, primarily as a response to the perceived health and conservation benefits. While it is likely that conventional farming will be able to respond rapidly to variations in pest numbers and distribution resulting from climatic change, it is not clear if the same is true for organic farming. Few studies have looked at the responses of biological control organisms to climate change. Here, I review the direct and indirect effects of changes in temperature, atmospheric carbon dioxide and other climatic factors on the predators, parasitoids and pathogens of pest insects in temperate agriculture. Finally, I consider what research is needed to manage the anticipated change in pest insect dynamics and distributions.
The science of climate change has matured considerably during the past decade, both relative to the strength of the evidence documenting the ongoing anthropogenic climate change and in terms of the quality of climate models projecting future changes in climate. Concomitantly, modeling studies to project the likely impacts of climate change on agricultural production also have become more sophisticated. Nonetheless, agricultural impact assessments still do not account for all important factors; for example, potential changes in yield losses due to altered dynamics and intensity of pests (insects, plant pathogens, and weeds) under climate change are generally ignored — an important omission, given the significant role of plant pests in constraining the production of food and fiber worldwide. This paper highlights selected challenges that must be overcome before we can hope to quantify the impacts of a changing climate on plant disease intensity and yield loss. They pertain both to retrospective analyses seeking to identify fingerprints related to climate change in long-term plant-disease records, as well as to the use of mathematical models to predict likely impacts on plant pathosystems in the future. The use of climate-change fingerprints has been limited because time series containing disease variables collected in a standardized manner are unavailable for most plant pathogens; in cases where such long-term records do exist, trends are often confounded by changes in biological or management factors over time. As for the use of models for impact assessment, key challenges pertain to uncertainty in input variables, the difficulty in predicting biological responses in the presence of nonlinearities and thresholds, and the high likelihood of genetic adaptation to climate change.
Hydrologic modeling of the responses of two study watersheds to climate change is presented. The watersheds are the Upper Campbell and the Illecillewaet watersheds located in British Columbia. The first is a maritime watershed located on the eastern slopes of the Vancouver Island mountains; the second is located in the Selkirk Mountains in Eastern British Columbia. The Canadian Climate Centre General Circulation model has been used for the prediction of potential effects of climate change on meteorological parameters. In addition to the changes in the amounts of precipitation and temperature usually assumed in hydrologic climate change studies, other meteorological and climatic parameters also considered are the effect of climate on the spatial distribution of precipitation with elevation, as well as on cloud cover, glaciers, vegetation distribution, vegetation biomass production, and plant physiology. The results showed that the mean annual temperature in the two watersheds could increase by more than 3°C and the annual basinwide precipitation could increase by 7.5% in the Upper Campbell watershed and by about 17% in the Illecillewaet watershed. The higher temperatures changed some snowfall to rainfall and the extra precipitation was mainly in the form of rain. The increase of the CO2 concentration caused stomata closure that reduced evapotranspiration. This effect was compensated by increased biomass in the Upper Campbell watershed, but not in the Illecillewaet watershed. These changes produced higher flows in winter and smaller flows in summer. The largest change in the hydrograph shape was in the Illecillewaet watershed where the mean annual maximum daily flow decreased by about 13% and its frequency was reduced. On the other hand, the mean annual runoff increased by 21%. In contrast, although the shape of the simulated annual hydrograph of the Upper Campbell watershed was not affected, magnitude and frequency of the annual maximum precipitation increased. Also, the mean annual runoff in the Upper Campbell watershed increased by 7.5%. These results indicate that different management procedures may be needed to minimize the effects of climate change on the water resources of the two climatically different watersheds and the regions that they represent.
Is sea-level rise and (or) climate change responsible for current declines in important coastal bird populations in Great Britain, and how might these processes affect bird populations in future? We review the current status of coastal bird populations in Britain and identify two important species, Common Redshank (Tringa totanus) and Twite (Carduelis flavirostris), whose populations are currently declining. We then review the evidence relating to the causes of these declines. There is evidence that habitat loss, driven by sea-level rise and climate change (e.g., an increase in wind and wave energy reaching the coast due to an increase in the frequency of storms), could have contributed to the decline in Twite. Common Redshank numbers are declining because of changes in grazing management, not sea-level rise. Populations that are currently stable or increasing, such as wintering waders and wildfowl, might in future experience declines in abundance because there is a link between climate, food supply, and bird abundance. There are insufficient reliable data at present to allow us to predict future changes with any confidence. Sea-level rise and climate change are currently important issues facing coastal zone management in Great Britain, and these issues may become even more pressing in future. But, in addition to these environmental processes, coastal bird populations are affected by a range of other anthropogenic factors. Conservationists, therefore, need to identify important bird populations that are (or could be in future) detrimentally affected by any of these activities rather than focusing exclusively on single issues such as sea-level rise. Allowing the sea to breach existing sea defences, thereby creating new saltmarsh, provides a way forward but is not without its practical and political difficulties.Key words: coastal birds, sea-level rise, climate change, population decline, habitat loss, saltmarsh.
Under the background of global climate change, the climate in semiarid region of west Jilin Province changed greatly, producing a profound impact on the corn production in this region. In this study, the corn seeds were under three treatments (accelerating germination at 10 and 25 degrees C, and dry seeds), and a field experiment with early sowing and traditional sowing was conducted in 2008 to investigate the effects of early sowing these seeds on the seedling emergence, growth, and yield, and compare the effects of early sowing and traditional sowing dates on the corn production and yield. In 1961-2010, the first day of the growth season of corn in semiarid region of west Jilin Province was advanced, the air temperature increased significantly, and the precipitation displayed a decreasing trend. At present, the corn sowing date in this region could be advanced to 11th, April. Accelerating germination at 10 degrees C, directly sowing dry seeds, and bed-irrigation sowing all benefited the seedling emergence and cold resistance of early-sown seeds, and the corn plant height and leaf area under early sowing were significantly higher, with the yield increased by 35% - 48%, compared with those under traditional sowing.
1 Broad beans (Vicia faba L.) were grown at either ambient (350 μL/L) or elevated (700 μL/L) CO2. Elevated CO2 increased shoot weight by 14% and root weight by 24% compared to ambient, but did not affect flowering.
2 A single pea aphid (Acyrthosiphon pisum (Harris)) and its progeny decreased shoot and root weights by 20 and 24%, respectively, at ambient CO2 after 20 days, but did not affect flower number. At elevated CO2A. pisum decreased shoot and root weights by 27 and 34% and flower number decreased by 73%.
3 A single glasshouse and potato aphid (Aulacorthum solani (Kaltenbach)) and its progeny had no effect on the growth of bean plants after 20 days at ambient CO2. At elevated CO2, A. solani decreased shoot and root weights by 20 and 18%, and flower number by 60%.
4 The large reduction in flowering caused by aphids at elevated CO2 suggests a change in resource allocation within the plants to compensate for aphid infestation.
5 Aphid density was unaffected by elevated CO2, although there were significant effects of CO2 on the resulting population structure of both A. pisum and A solani. We suggest that at elevated CO2, aphids appear not to achieve their maximum reproductive potential and their populations are limited by the lower carrying capacity of their host plants.
Clonal plants of three genotypes of Lotus corniculatus (cv Leo) were grown in eight controlled environments under combinations of two temperature regimes, two CO2 concentrations and two watering regimes. Condensed tannins (proanthocyanidins), in-vitro digestibility, initial rates of gas evolution (as an indicator of the initial rates of fermentation of the substrate), volatile fatty acid evolution, and non-structural carbohydrate (NSC) levels were determined in leaves, stems and roots at full flowering. Under control conditions (average midsummer conditions in the United Kingdom) the total condensed tannin content of leaves varied six-fold between genotypes but condensed tannin contents in stems and roots were similar. Condensed tannin levels were significantly increased in leaves and stems of all three genotypes by doubling the CO2 concentration while raising the temperature towards the optimum for growth significantly reduced condensed tannin levels. Drought stress significantly reduced condensed tannin levels in leaves and, particularly, in roots. Nutritive value was inversely related to condensed tannin levels in leaves and a negative relationship was observed between condensed tannin concentrations of more than 25–30 g kg−1 dry matter and the initial rates of gas evolution when subjected to in-vitro fermentation with rumen micro-organisms. In leaves, digestibility was significantly increased by drought and by increasing temperature but reduced by high CO2. In stems, digestibility was significantly increased by drought, but not significantly affected by increasing temperature, or by high CO2 alone. In roots, digestibility was significantly increased by drought, and decreased by increasing temperature or CO2. Increasing the growth temperature towards optimum growth reduced the content of NSC in all tissues with the greatest changes occurring in root tissue. Doubling the CO2 concentration increased NSC levels in leaves and stems with starch content more than doubled under high CO2 while, in roots, increased levels were only observed in combination with drought stress. There was a linear correlation between condensed tannin concentration and total NSC that was positive for leaves, neutral for stems and negative for roots. The relationship between carbohydrate levels and rates of gas production was negative for leaves and positive for stem and roots.© 1999 Society of Chemical Industry
Recent estimates for global warming predict increases in global mean surface air temperatures (relative to 1990) of between 1 and 3.5 °C, by 2100. The impact of such changes on agricultural systems in mid- to high-latitude regions are predicted to be less severe than in low-latitude regions, and possibly even beneficial, although the influence of pests and diseases is rarely taken into account. Most studies have concluded that insect pests will generally become more abundant as temperatures increase, through a number of inter-related processes, including range extensions and phenological changes, as well as increased rates of population development, growth, migration and over-wintering. A gradual, continuing rise in atmospheric CO2 will affect pest species directly (i.e. the CO2 fertilization effect) and indirectly (via interactions with other environmental variables). However, individual species responses to elevated CO2 vary: consumption rates of insect herbivores generally increase, but this does not necessarily compensate fully for reduced leaf nitrogen. The consequent effects on performance are strongly mediated via the host species. Some recent experiments under elevated CO2 have suggested that aphids may become more serious pests, although other studies have discerned no significant effects on sap-feeding homopterans. However, few, if any of these experiments have fully considered the effects on pest population dynamics. Climate change is also considered from the perspective of changes in the distribution and abundance of species and communities. Marked changes in the distribution of well-documented species – including Odonata, Orthoptera and Lepidoptera – in north-western Europe, in response to unusually hot summers, provide useful indications of the potential effects of climate change. Migrant pests are expected to respond more quickly to climate change than plants, and may be able to colonize newly available crops/habitats. Range expansions, and the removal of edge effects, could result in the increased abundance of species presently near the northern limits of their ranges in the UK. However, barriers to range expansions, or shifts, may include biotic (competition, predation, parasitism and disease), as well as abiotic, factors. Climatic phenomena, ecosystem processes and human activities are interactive and interdependent, making long-term predictions extremely tenuous. Nevertheless, it appears prudent to prepare for the possibility of increases in the diversity and abundance of pest species in the UK, in the context of climate change.
A model that described the summer population dynamics of the cereal aphid Sitobion avenae (Carter et al., 1982) was modified and extended to include the population dynamics of the aphidophagous predator Coccinella septempunctata. New equations were formulated to describe the dependence of aphid development and reproduction on temperature. The predation interaction between the aphid and coccinellid was formulated with a modified form of the temperature-mediated functional response equation proposed by Mack et al. (1981) and Mack and Smilowitz (1982). The output obtained from the model provided a reasonably good fit to field data. Recommendations for further research are made based on these results and on a sensitivity analysis reported elsewhere (Skirvin et al., 1996).
The effect of weather on the size of British butterfly populations was studied using national weather records and the Butterfly Monitoring Scheme (BMS), a national database that has measured butterfly abundance since 1976.
Strong associations between weather and population fluctuations and trends were found in 28 of 31 species studied . The main positive associations were with warm summer (especially June) temperature during the current and previous year, low rainfall in the current year and high rainfall in the previous year . Most bivoltine species benefited from warm June weather in the current year, three spring species and two that overwinter as adults benefited from warm weather in the previous summer, and most species with moist or semi‐shaded habitats increased following high rainfall and cooler weather in the previous year.
Simple models incorporating weather variables and density effects were constructed for each species using the first 15 years’ population data (1976–90) . These fitted the observed data for that period well (median R ² = 70%). Models were less good at predicting changes in abundance over the next 7 years (1991–97), although significant predictive success was obtained.
Parameter values of models were then adjusted to incorporate the full 22‐year data‐run . For the eight species whose models had best predicted population changes or fitted the data well ( R ² > 85%), models were run from 1767 to 1997, using historical weather records, to ‘predict’ trends in abundance over the past two centuries . For three species it was possible to compare predicted past trends with contemporary accounts of abundance since 1800 . In each case, the match between predictions and these qualitative assessments was good.
Models were also used to predict future changes in abundance, using three published scenarios for climate change . Most, but not all, species are predicted to increase in the UK under warmer climates, a few species stayed stable, and only one species – the agricultural pest Pieris brassicae (Cabbage White) – is predicted to decline.
In order to assess the influence of water stress on the development of Sphaeropsis sapinea cankers in Pings halepensis, the stems of 4- to 5-year-old potted seedlings were artificially inoculated with the fungus before and after being kept at controlled water regimes from April 1997 to March 1998. In the pre-water-stress inoculation experiment, the canker length, measured 5 months after inoculation (September 1997), was greater in seedlings predisposed to extreme water deficit (midday needle water potential between -4.5 and -5.5 MPa). In the post-water-stress inoculation experiment, the fungus was inoculated in April 1998, after irrigation had enabled the seedlings to resume normal needle water potential. In this case also, at 5 months after inoculation, longer cankers were visible in seedlings that had been subjected to extreme water deficit. These findings suggest that the occurrence of marked water stress, although apparently tolerated by Aleppo pine, can enhance the development of S. sapinea cankers in this species, regardless of whether the stress occurs before or after infection by the fungus.
AimSpatial models generated in a geographical information system (GIS) are utilized to predict shifts in the distribution and diversity of tropical forests in Costa Rica in response to climate change.LocationAnalyses were conducted using the Holdridge life zone classification system for the Central American country of Costa Rica.Methods
Mean annual precipitation and temperature ranges were varied to reflect different magnitudes of climate change and then used to predict the distributions of nineteen forest types (life zones). Holdridge et al.'s (1971) field survey data of species richness and endemism for ten Costa Rican life zones were also analysed and considered in view of the climate change scenarios.ResultsThe scenarios indicated that shifts in the distribution of tropical forest life zones are likely to occur as a result of climatic changes. High elevation life zones were shown to be more sensitive to changes in temperature, while lower elevation life zones tended to be more sensitive to changes in precipitation. Regional life zone diversity was greatly reduced in an extreme wet and warm climate scenario. Three elevation-associated life zones (lower montane rain forest, montane rain forest, and premontane rain forest) ranked in the top four in percentage number of endemic species. The lowland seasonally dry forest life zone ranked second in this group, suggesting that this life zone has a unique species composition in comparison with other lowland Holdridge life zones. Of the nineteen life zones, these four life zones displayed particular sensitivity to the climate changes modelled here.Main conclusionsElevation-associated life zones may be particularly vulnerable to future climatic changes. This is also true of lowland seasonally dry forest. Geographical regions in Costa Rica that contain these life zones are likely to warrant special management and conservation attention in the event of predicted climate change.
Gives a case study of the advantages and disadvantages of linking biophysical and economic models in attempts to assess the effects of climatic change. Here, the effects of changes in temperature induced by a doubling of present-day atmospheric carbon dioxide concentration (2 x CO2) on the productivity of northern hemisphere boreal forests are assessed using a simple forest growth model. Results indicate that the location of the boreal zone under the GISS 2 x CO2 scenario would be shifted northwards by 500-1000 km, and forest growth would increase in all parts of the study area with the greatest increases occurring in northern maritime regions. The results reported here are used in Part 1, Section 6, of this book as inputs to a further set of experiments to assess the economic implications of productivity changes on the world's forest sector. -from Editors
Five types of climate (scenarios) are simulated: 1) A baseline climate, representing present-day (1951-1980) climatic conditions. 2) An anomalously cool decade taken from the historical instrumental record. 3) An ensemble of the 10 coolest years since 1930, selected from the climatic record. 4) An ensemble of the 10 warmest years since 1930 (also selected from the climatic record). 5) The climate derived from the estimates of the Goddard Institute for Space Studies (GISS) general circulation model, for doubled concentrations of atmospheric carbon dioxide. These scenarios have been based on the long temperature record at Stykkisholmur, which is a representative station for the whole country. The contrast in effects between a cooler-than-average and a warmer-than-average climate in Iceland is indicated clearly by the results. A temperature increase of 4.0°C at Stykkisholmur, estimated for the 2 X CO2 scenario, would increase the potential farming area in Iceland and open up new farming options similar to those presently available in Scotland. However, it is clear that farmers should always be prepared for cold years, even if the mean climate is warming, especially if the warmer conditions encourage farmers to cultivate new crops with an equivalent degree of risk as formerly. Finally, it is recommended that research into climate impacts on Icelandic agriculture should focus on the present marginal areas, in the northern upland regions (where grass production has been uncertain in cool years) and in the more favorable areas (where barley and vegetable cultivation has succeeded in warmer years). -from Editors
This case study seeks to evaluate the present-day sensitivity of agriculture, particularly crop yields, to climatic variations in the northern European USSR, and to assess the likely impacts of future climatic change. Studies that consider three different aspects of this issue are reported, each conducted in a different region: effects of climate on spring wheat yields in the Cherdyn region; on winter rye yields in relation to the wider natural environment in the Leningrad region; and on regional production and crop allocation for a range of crops in the Central region (around Moscow). Each utilizes mathematical models to convert climatic anomalies to estimates of impact. Four types of model are employed: a regression model and two dynamic crop-weather models to estimate crop yields, a global ecological model for evaluating environmental impacts, and a regional agricultural planning model for assessing the costs of adjusting crop allocation strategies to optimize production. -from Editors
This case study evaluates the effects of specified climatic changes on plant productivity, on rice production and on the national rice market in Japan, and considers possible technological or policy responses to these changes. The focus of the study is on the coolest regions of Japan (in the northernmost districts of Hokkaido and Tohoku, and at higher elevations) which are the areas where rice crops are most susceptible to cool temperature damage (particularly in the summer months). Three types of "impact model' have been employed to assess the effects of climate on production. In line with the four other case studies in cool temperate and cold regions considered in the IIASA/UNEP project and reported in this volume (in Saskatchewan, Iceland, Finland and the northern European USSR), experiments have been conducted to estimate the impacts of several different climatic scenarios. The implications of the modeled impacts on rice point to several adjustments in government pricing and subsidization policies that would be necessary to stabilize the domestic rice balance, including a longer-term movement towards minimized government intervention and a liberalized rice market. Finally, the results of this assessment indicate that research into methods of coping with climatic change should be a high priority in government planning. -from Editors
This case study attempts to quantify the effect of climate on Finnish agriculture and, in particular, to study how variations in climate influence yields, production and the farm economy. Three studies of yield responses to climatic variations are reported. Each utilizes regression models to estimate yield for a particular climate (represented by a set of meteorological data). Results indicate that changes in temperature and precipitation implied in the climatic scenarios can have a marked effect on crop yields. A cooler climate generally leads to below-average yields both in northern and in southern Finland, but this effect may be compensated, to some extent, in southern Finland by increases in precipitation that would remove the risk of summer drought. In the north of Finland precipitation excess, rather than deficit, depresses yields so that for climatic warming to be beneficial for yields in this region, precipitation totals should not be too high. In general, however, warmer conditions would raise crop yields (particularly those implied in the 2 X CO2 scenario), and increase farm incomes if prices and costs do not change. However, an increase in yields would worsen the over-supply problem and the government might be forced to take further actions to cut production. Nonetheless, for farmers the effects of an increase in temperature would be more tangible. Cultivation boundaries of certain crops will move northwards, crop selection will be less difficult and new, later developing varieties could be introduced into southern regions, with implications for plant breeding and agriculture extension services in Finland. -from Editors
Higher atmospheric CO2 concentrations are potentially beneficial to agriculture because they usually stimulate plant growth. The typical magnitude of the "CO2 fertilizing effect' is a 30-40% increase in yield for a doubling of CO2 concentration to 700 ppmv. The main mechanisms of the "CO2-fertilizing effect' involve several physiological phenomena, some that are certainly primary (stimulation of photosynthesis, suppression of photorespiration, reduction in stomatal aperture) and others that seem so far to be primary but may turn out not to be (greater leaf area development and branching, reduced stomatal frequency, reduced dark respiration, changes to reproductive development). It is often assumed that the reduction in stomatal conductance at high CO2 concentration will lead to reduced evapotranspiration from vegetated regions, all else being equal. For annual crops like cereals, a warmer climate will tend to reduce yield owing to the faster attainment of physiological maturity, but the size of the CO2-fertilizing effect on yield for a currently adapted variety is similar to that of the associated temperature-dependent reduction of yield. So the net effect on cereal yield in a region will depend on the success at introducing slower maturing and CO2-responsive varieties to compensate for faster development in warm conditions, and on whether the climate change involves more or less rainfall in the region. -from Author
Tropical cyclones rank with earthquakes as the major geophysical causes of loss of life and property. It is therefore of practical as well as scientific interest to estimate the changes in tropical cyclone frequency and intensity that might result from short term human-induced alterations of the climate. In this spirit a simple Carnot cycle model is used to estimate the maximum intensity of tropical cyclones under the somewhat warmer conditions expected to result from increased atmospheric CO2 content. Estimates based on August mean conditions over the tropical oceans predicted by a general circulation model with twice the present CO2 content yield a 40-50% increase in the destructive potential of hurricanes.
Most climate impact studies rely on changes in means of meteorological variables, such as temperature, to estimate potential climate impacts, including effects on agricultural production. However, extreme meteorological events, say, a short period of abnormally high temperatures, can have a significant harmful effect on crop growth and final yield. The characteristics of daily temperature time series, specifically mean, variance and autocorrelation, are analyzed to determine possible ranges of probabilities of certain extreme temperature events with changes in mean temperature of the time series. -from Authors
The environmental requirements for growth of winter, spring, and fallsown spring wheats in North America are specified and compared to temperature results from the control run of the Goddard Institute for Space Studies general circulation model (GISS GCM) and observed precipitation in order to generate a simulated map of current wheat production regions. The simulation agrees substantially with the actual map of wheat-growing regions in North America. Results from a doubled CO2 run of the climate model are then used to generate wheat regions under the new climatic conditions. In the simulation, areas of production increase in North America, particularly in Canada, due to increased growing degree units (GDU). Although wheat classifications may change, major wheat regions in the United States remain the same under simulated doubled CO2 conditions. The wheat-growing region of Mexico is identified as vulnerable due to high temperature stress. Higher mean temperatures during wheat growth, particularly during the reproductive stages, may increase the need for earlier-maturing, more heat-tolerant cultivars throughout North, America. The soil moisture diagnostic of the climate model is used to analyze potential water availability in the major wheat region of the Southern Great Plains.
As climate changes due to the increase of greenhouse gases, there is the potential for climate variability to change as well. The change in variability of temperature and precipitation in a transient climate simulation, where trace gases are allowed to increase gradually, and in the doubled CO2 climate is investigated using the GISS general circulation model. The current climate control run is compared with observations and with the climate change simulations for variability on three time-scales: interannual variability, daily variability, and the amplitude of the diurnal cycle. The results show that the modeled variability is often larger than observed, especially in late summer, possibly due to the crude ground hydrology. In the warmer climates, temperature variability and the diurnal cycle amplitude usually decrease, in conjunction with a decrease in the latitudinal temperature gradient and the increased greenhouse inhibition of radiative cooling. Precipitation variability generally changes with the same sign as the mean precipitation itself, usually increasing in the warmer climate. Changes at a particular grid box are often not significant, with the prevailing tendency determined from a broader sampling. Little change is seen in daily persistence. The results are relevant to the continuing assessments of climate change impacts on society, though their use should be tempered by appreciation of the model deficiencies for the current climate.
Atmospheric carbon dioxide (CO2) concentration will probably double by the middle of the next century. Since this is widely expected to increase crop yields, the Department of Energy has established a research program to gather data on the effects of CO2 on plants and to develop models that can be used to predict how plants will behave in a future high-CO2 world.This paper identifies strengths and weaknesses in the knowledge base for modelling plant responses to CO2. It is based on an extensive tabulation of published information on responses of ten leading crop species to elevated CO2. The response variables selected for examination were: (a) net carbon exchange rate, (b) net assimilation rate, (c) biomass accumulation, (d) root:shoot ratio, (e) harvest index, (f) conductance, (g) transpiration rate and (h) yield. The results were expressed as a predicted percentage change of the variable in response to a doubled CO2 concentration. In most instances, a linear model was used to fit the response data.Overall, the net CO2 exchange rate of crops increased 52% on first exposure to a doubled CO2 concentration, but was only 29% higher after the plants had acclimatized to the new concentration. For net assimilation rate, the increases were smaller, but fell with time in a similar way. The C4 crops responded very much less than C3 crops. The responses of biomass accumulation and yield were similar to that for carbon fixation rate. Yield increased on average 41% for a doubling of CO2 concentration. The variation in harvest index was small and erratic except for soybean, where it decreased with a doubling of CO2 concentration. Conductance and transpiration were both inversely related to CO2 concentration. Transpiration decreased 23% on average for a doubling of CO2.Crop responses to CO2 during water stress were variable probably because high CO2 both increased leaf area (which increases water use) and reduced stomatal conductance (which decreases water use). However, low nutrient concentrations limited the responses of most crops to CO2. The absolute increase in photosynthetic rate in response to high CO2 concentration was always greater in high light than in low light, but this was not necessarily true of the relative increase. In all except one study, responses to CO2 were larger at high temperature than at low. Most of these studies were done in high light intensity. In low light intensity, the effect of temperature on the CO2 response was smaller.
The possibility that the greenhouse warming predicted by the GISS general-circulation model and other GCMs could lead to severe droughts is investigated by means of numerical simulations, with a focus on the role of potential evapotranspiration E(P). The relationships between precipitation (P), E(P), soil moisture, and vegetation changes in GCMs are discussed; the empirically derived Palmer drought-intensity index and a new supply-demand index (SDDI) based on changes in P - E(P) are described; and simulation results for the period 1960-2060 are presented in extensive tables, graphs, and computer-generated color maps. Simulations with both drought indices predict increasing drought frequency for the U.S., with effects already apparent in the 1990s and a 50-percent frequency of severe droughts by the 2050s. Analyses of arid periods during the Mesozoic and Cenozoic are shown to support the use of the SDDI in GCM drought prediction.