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Model Selection and Inference: A Practical Information-Theoretic Approach
... • M t×a (capture probability varies with sampling occasion, individual fish age-class, and the interaction between occasion and age-class) Models were fitted by using maximum likelihood estimation via the software package RMark (Laake 2013). For each year of the study, Akaike's information criterion corrected for small sample sizes (AIC c ) was calculated for all models to select the model with the best out-of-sample predictive performance for that year (Akaike 1973;Burnham and Anderson 2002). Final estimates of abundance and juvenile recruitment for the year of interest were taken from the one model with the highest Akaike weight for that year (Burnham and Anderson 2002). ...
... For each year of the study, Akaike's information criterion corrected for small sample sizes (AIC c ) was calculated for all models to select the model with the best out-of-sample predictive performance for that year (Akaike 1973;Burnham and Anderson 2002). Final estimates of abundance and juvenile recruitment for the year of interest were taken from the one model with the highest Akaike weight for that year (Burnham and Anderson 2002). We constructed lognormal 95% CIs around all abundance estimates within RMark (White and Burnham 1999;Laake 2013), and we visually compared the overlap of CIs between years to assess differences in abundance and recruitment over time. ...
... The ΔAIC c indicates the difference between the calculated AIC c value for the model in that row and the AIC c for the model with the lowest AIC c value for that year. Akaike weight was calculated according to Burnham and Anderson (2002). Bold text indicates the model with the highest Akaike weight for each year. ...
Objective
The objective of this study was to estimate the population size and annual recruitment of Shortnose Sturgeon Accipenser brevirostrum in the Altamaha River estuary in Georgia, United States, during an 11‐year period. The Shortnose Sturgeon is an endangered fish species that occupies rivers on the east coast of North America. Previous studies have suggested that the Altamaha River supports the largest population of Shortnose Sturgeon in the southern United States; however, the status of the population has not been assessed in 11 years.
Methods
We used entanglement gears to capture Shortnose Sturgeon in the Altamaha River estuary, marked them, and used an established statistical method (closed‐population capture–mark–recapture models) to annually estimate total population size and age‐1 recruitment from 2012 to 2022.
Result
We were able to estimate the size of age‐1 cohorts in 7 of the 11 years of data collection. Point estimates of annual age‐1 recruitment varied between 113 and 1021 individuals, and total population size varied between 452 (95% confidence interval [CI]: 116–2277) and 5054 individuals (95% CI: 2155–13,267).
Conclusion
Recruitment of age‐1 juveniles was variable, suggesting that reproduction success is inconsistent between years in the Altamaha River. The results of this study, in combination with previous work, do not show any clear trends in Altamaha River Shortnose Sturgeon population abundance or recruitment. The population seems to be stable, but in the absence of historical population numbers, it is unclear whether the population should be considered recovered or is stagnated in its recovery.
... To assess whether buffer land cover conditions were associated with water column nutrient transformation rates, we used an information criteria approach that compared linear regression models (parameterized using ordinary least squared regression) between K and different potential predictor variables (Burnham & Anderson, 1998. We looked at residual versus observation plots, quartile-quartile plots comparing residuals with a theoretical normal distribution, scale-location plots, and residuals versus leverage plots (all available in base R using the plot function) to assess whether highly supported models met assumptions of linearity, normally distributed residuals, homogeneity of variance and outliers. ...
... Given the small sample size, more complicated models were not appropriate (e.g., mixed-effects models with site as a random effect could not be reliably parameterized). For each model, the Akaike information criterion (corrected for small sample size; AIC c ) value was calculated and models were ranked according to the difference (Δ) in AIC c values (lower values indicate more support; Burnham & Anderson, 1998). Typically ΔAIC c is estimated relative to the best model, and models with a ΔAIC c < 2 have a fit equivalent to the best model, while models with ΔAIC c > 10 are usually considered to have worse fit than the best model, although these are rules of thumb rather than objective thresholds (Burnham & Anderson, 1998. ...
... For each model, the Akaike information criterion (corrected for small sample size; AIC c ) value was calculated and models were ranked according to the difference (Δ) in AIC c values (lower values indicate more support; Burnham & Anderson, 1998). Typically ΔAIC c is estimated relative to the best model, and models with a ΔAIC c < 2 have a fit equivalent to the best model, while models with ΔAIC c > 10 are usually considered to have worse fit than the best model, although these are rules of thumb rather than objective thresholds (Burnham & Anderson, 1998. If two models have ΔAIC c < 2, but one model has more parameters than the other, the model with fewer parameters is generally considered to have stronger support (Arnold, 2010). ...
Watershed nutrient management often focuses on actions that reduce the movement of nitrogen (N) and phosphorus (P) from agricultural lands into streams. One area of management focus is the buffer of land adjacent to streams. Wetlands and forests in this buffer can intercept and retain N and P from the landscape. In addition to directly intercepting agricultural nutrients, natural habitats in the buffer can alter stream geomorphology and influence the in‐stream processing and transformation of N and P to less labile and mobile forms. Here, we assess the influence of buffer land cover on in‐stream processing of N and P. We measured nutrient dynamics in the water column and sediments of agricultural streams in the Fox River and Duck Creek watersheds (WI, USA) during the growing season. In these streams, water column processing was low, possibly due to a lack of primary producers in the water column. Water column P processing was weakly associated with wetland land cover in the buffer, but buffer land cover had no clear effect on inorganic N processing. On the other hand, sediments were almost always a source of inorganic P and a sink for inorganic N. Sediment P release was higher in streams with more agricultural land cover in the buffer. Sediments in streams with agricultural land cover in the buffer also removed more nitrate, even after accounting for the greater availability of nitrate in those streams. The buffer land cover conditions we quantified occupy a very small portion of the overall watershed (100 m wide, for 1 km upstream of the study site) but nevertheless appear to influence in‐stream cycling of N and P. For P management, reducing agricultural land cover in buffers is already a priority due to the ability of wetlands and forests to intercept nutrients, but this study suggests there may be some additional benefit due to changes in in‐stream P processing.
... The model with the lowest value of AIC is the best-supported model. If the p-value of the likelihood ratio test is greater than 0.05, the model with the fewest predictors is the best model due to its parsimony/simplicity (Burnham and Anderson, 2002;Manly et al., 2002), i.e. the model that best explains the distribution of each species of LH. I computed delta AIC (ΔAIC) as the difference in AIC values between each candidate model and the best model. ...
... I computed delta AIC (ΔAIC) as the difference in AIC values between each candidate model and the best model. I used the difference as follows to determine the level of support for each candidate model (Burnham and Anderson, 2002;Fabozzi et al., 2014): If (i) ΔAIC < 2, this indicates there is substantial evidence to support the candidate model (i.e., the candidate model is almost as good as the best model), however, in the event of several models ...
... The Akaike weights are the probability that the candidate model is the best among a set of candidate models (Burnham and Anderson, 2002;Manly et al., 2002;Fabozzi et al., 2014). ...
The research aimed to contribute towards a better understanding of the historical and current distribution and movement patterns of LH in the Limpopo National Park (LNP), thereby creating a basis and providing evidence for the management and further development of the Greater Limpopo Transfrontier Park (GLTP). I combined historical and current LH occurrence data (1500-2021) based on a systematic literature search, census reports, online databases, dung count transects, and camera trap surveys to reconstruct the historical distribution and movement patterns of LH species using ArcGIS 10.8.1 in five different periods: (i) prehistoric period (around 1500), (ii) peak of the colonial period (1800-1975), (iii) post-colonial/civil war period (1976-2001), (iv) post-proclamation of GLTP (2002-2018), and (v) current period (2019-2021). I assessed the distribution patterns and the relative abundance of reintroduced LH (2019-2021) through camera traps in five habitat types and the wildlife reintroduced and not-reintroduced areas. I used aerial censuses (2001-2018), camera trap surveys, and dung count transects (2019-2021) to assess how ecological and anthropogenic factors influence the distribution of LH in 5 km x 5 km grid cells through a generalized linear model (GLM). found a dramatic collapse of LH populations between the peak of the colonial and the post-colonial periods (1800-2001), followed by a slight recovery from the post-proclamation of GLTP to the current period (2002-2021). Elephants, buffalos, and zebra appear to recover better than giraffes, eland, blue wildebeest, and white rhinos. There were LH movements in the past, which ceased in the Civil War period. Currently, there is evidence of the re-establishment of wildlife movements in the LNP. The distribution and abundance of LH were associated with habitat types rather than distance to the reintroduction site. Habitat types and rainfall were the most influential factors, while cattle grazing areas were the worst factors associated with the prevalence of LH. Some species tended to avoid human settlements, while others seemed attracted to human settlements. Overall, the LH distribution and movement patterns decreased over time, and currently, the restoration is in an early and vulnerable state. These findings suggest connectivity between different habitats within the LNP despite intense human presence in the core area and buffer zone. Therefore, further
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efforts are necessary to strengthen the slow recovery of LH in the LNP. The findings highlight the need for further research on connectivity in the larger GLTP through GPS tracking of LH species. It would also allow investigating/quantifying the potential risk of human-wildlife conflict at finer spatial scales to improve future management in the LNP and GLTP.
... Third, after establishing final base models, we used a stepwise procedure to simplify the base models (i.e., sequentially fit a series of a priori models with fewer parameters than the base model) to streamline the number of models fit. A more complex model (i.e., the model with greater number of parameters) was retained if the AIC of the model was > 2 AIC units lower than a simpler model, otherwise the simpler model was chosen (Akaike, 1973;Burnham and Anderson, 2002). AIC, rather than AICc or QAIC, was appropriate for our data because the ratio of observations N to parameters K in models was high for all datasets (N/K>>40, Burnham and Anderson, 2002) and our models were more complex than previously fit for these data where goodness-of-fit was judged adequate (Hastings et al., 2011;Fritz et al., 2014;Maniscalco, 2014). ...
... A more complex model (i.e., the model with greater number of parameters) was retained if the AIC of the model was > 2 AIC units lower than a simpler model, otherwise the simpler model was chosen (Akaike, 1973;Burnham and Anderson, 2002). AIC, rather than AICc or QAIC, was appropriate for our data because the ratio of observations N to parameters K in models was high for all datasets (N/K>>40, Burnham and Anderson, 2002) and our models were more complex than previously fit for these data where goodness-of-fit was judged adequate (Hastings et al., 2011;Fritz et al., 2014;Maniscalco, 2014). ...
The North Pacific marine heatwave of 2014–2016 (PMH), one of the most geographically-extensive and severe marine heatwaves on record, resulted in widespread and persistent perturbation of the Gulf of Alaska and California Current ecosystems. Negative effects of the PMH on marine mammals have been observed, but are not yet well understood. The endangered Steller sea lion Eumetopias jubatus is an important top predator in the Gulf of Alaska that is also particularly vulnerable to sudden or severe ecosystem shifts. We examined survival of 4,178 known-aged Steller sea lions marked from 2000 to 2016 from Kodiak Island through Southeast Alaska, using mark-recapture models and 12,811 resightings collected from 2001 to 2021. Survival of adult females aged 3–15 was reduced -0.05 to -0.23 during the PMH in the areas east, but not west, of Cook Inlet. Survival of Kodiak females was unaffected by the PMH, but survival of Sugarloaf females aged 5–8 was reduced -0.13 from summer 2015 to summer 2016. Lowest survival in Southeast Alaska occurred from summer 2016 to summer 2017, but was also reduced from summer 2014 to summer 2016. Reduced survival continued post-PMH in Kenai Peninsula/Prince William Sound, but not in Southeast Alaska. Survival of adult males was insensitive to the PMH, except in Southeast Alaska where male survival was reduced -0.25 from summer 2016 to summer 2017. Prolonged or intermittent high adult female mortality may reduce population growth and initiate regional declines. Survival response of Steller sea lions to the PMH varied regionally despite similar patterns of ocean warming throughout our study area, suggesting areas east versus west of Cook Inlet were affected differently by the PMH, perhaps due to habitat and oceanographic differences.
... To overcome this potential fitting issue, AICc was developed: AICc stands for AIC corrected for a short sample size. [12] Corrected Akaike's Information Criterions as follows: ...
... [3][4][5][6][7][8][9][10][11][12][13] for theAIC and BIC values that were used to make comparisons between different models Cox regression model and Competing risk regression in order to choose the model that best fits our data on leukemia cancer. The findings indicated that the competing risk regression model was better for our leukemia research data since its AIC, AICc, BIC values were the lowest when compared to the Competing Risk Model AIC and BIC values of 175.64, 176.383 and 192.37, respectively. ...
... The parameters used in the models to implement the nesting phenology (see section 2.3.2) and to estimate the annual number of nests for islets that were not monitored over a given season (see section 2.3.3) were fitted using the same statistical approach. First, the parameters are fitted using maximum likelihood, and then the models are selected using the Akaike Information Criterion (AIC) [33] and Akaike weight [34]. In short, AIC evaluates the quality of the fit that penalizes for overfitting too many parameters, while the Akaike weight gives the relative support of the different models, i.e. the probability for each model being the best one. ...
The loggerhead turtle Caretta caretta is a large marine turtle with a cosmopolitan repartition in warm and temperate waters of the planet. The South Pacific subpopulation is classified as ’Critically Endangered’ on the IUCN Red List, based on the estimated demographic decline. This precarious situation engages an urgent need to monitor nesting populations in order to highlight conservation priorities and to ensure their efficiency over time. New Caledonia encompasses a large number of micro and distant nesting sites, localized on coral islets widely distributed across its large lagoon. Adequately surveying nesting activities on those hard-to-reach beaches can prove to be challenging. As a result, important knowledge gaps prevail in those high-potential nesting habitats. For the first time, an innovative monitoring scheme was conducted to assess the intensity of nesting activities, considered as a proxy of the population size, on an exhaustive set of islets located in the ‘Grand Lagon Sud’ area. These data were analyzed using a set of statistical methods specially designed to produce phenology and nesting activity estimates using Bayesian methods. This analysis revealed that this rookery hosts a large nesting colony, with a mean annual estimate of 437 nests (95% Credible Interval = 328–582). These numbers exceed that of the previous estimated annual number of loggerhead turtle nests in New Caledonia, highlighting the exceptional nature of this area. Considering the fact that similar high-potential aggregations have been identified in other parts of New Caledonia, but failed to be comprehensively assessed to this day, we recommend carrying out this replicable monitoring scheme to other locations. It could allow a significant re-evaluation of the New Caledonian nesting population importance and, ultimately, of its prevailing responsibility for the protection of this patrimonial yet endangered species.
... By always keeping the same structure for random factors, the AR-1 correlation structure and the offset, we generated all possible competing models and employed the Akaike information criterion (AIC), using the values of DAIC <2 as the criterion for selecting the most parsimonious model (Burnham & Anderson, 2002). Following standard procedures, we calculated the Akaike weight for each candidate model (wi) as the relative strength of evidence, that is the probability of model i being the best-approximating model from the entire set of candidate models, and evidence ratios of the best models as the ratio of model weights. ...
Migration plays a central role in many ecological and evolutionary processes. Global patterns of climatic variation are having a profound influence upon animal migration patterns. Even though regular counts of bird migrations at bottleneck sites can certainly offer insights into how natural populations of different species at different scales are responding to changes in weather conditions, they have not yet been widely used. By analysing a time series of regular counts, collected during autumn, of 126 species migrating during the daytime through one of the most important migratory bottlenecks in Western Europe, we found that an increase in temperature at the regional scale, as well as a decrease in precipitation level during the breeding period, may result not only in a decrease in the migration rate during autumn but also in a delay in the timing of fall migration. Furthermore, adverse weather conditions at the local scale interrupted bird migration through the bottleneck until favourable weather conditions returned. Importantly, temporal variation in the number of migratory birds followed a nonlinear pattern, something which might be partially due to the idiosyncratic responses of migratory species with different life-history characteristics to changes in weather conditions. Our results highlight that migration is a nonlinear, multiscale and multi-faceted process, suggesting that it will be difficult to predict the responses of idiosyncratic migratory species to the unpredictable effects of climate change.
... In doing so, the analyses retained the subset of predictor parameters that were most important in explaining variation in catch, effort or CPUE [64]. Partial tests have been shown to be an insufficient measure of the appropriateness of alternatives to a model [see 68,71,72], so were only used to assess the influence of an independent parameter or interaction term once the final model had been chosen. For each final parsimonious GLMM, a partial Wald test (α = 0.01) was used to examine the null hypothesis that β i = 0 [55,64,73] for a retained parameter or the interaction term. ...
Extreme weather events across coastal environments are expected to increase in frequency under predicted climate change scenarios. These events can impact coastal recreational fisheries and their supporting ecosystems by influencing the productivity of fish stocks or altering behaviours and decision-making among fishers. Using off-site telephone/diary survey data on estuarine and oceanic recreational fishing activity in eastern Australia, we analyse interannual and geographic variability in bream (Acanthopagrus spp) and snapper (Chrysophrys auratus) catch, total effort and total catch per unit effort (CPUE) through a period (2013/2014, 2017/2018 and 2019/2020) that encompassed severe drought, bushfires and flooding. Interacting spatial and temporal differences were detected for bream and may reflect spatial variation in the intensity and extent of some of the extreme weather events. The catch of snapper did not change temporally, providing little evidence that this species’ catch may be influenced by the extreme weather events. Independent bioregional and temporal effects on effort were detected, while CPUE only showed significant bioregional differences. Although adverse conditions created by the extreme weather events may have dissuaded fisher participation and impacted effort, we propose that the observed temporal patterns in effort reflect the early influence of socio-economic changes brought on by the COVID-19 pandemic on coastal recreational fishing, over and above the impacts of extreme weather events. This study demonstrates how interrelated ecological, social and economic factors can shape coastal recreational fisheries and facilitates development of management strategies to address future threats to the sector.
... The corrected Akaike information criterion (AICc) was calculated to select the most accurate model (Burnham and Anderson, 2002). Models with AICc values that differ by less than 2 units do not present differences in terms of their plausibility. ...
Aspergillus flavus (A. flavus), a frequent contaminant in silage, is a significant producer of aflatoxins, notably the potent carcinogen aflatoxin B1. This contaminant poses a potential risk during the initial aerobic phase of ensiling. The present work studied the impact of temperature on A. flavus growth and aflatoxin B1 production in laboratory-scale sorghum silos during the initial aerobic phase. Growth curves of A. flavus were generated at various temperatures and modeled with the Gompertz model. Results indicated that the optimal temperature range for the maximum growth rate in sorghum mini-silos is between 25 and 30°C. Mold biomass and aflatoxin B1 levels were quantified using qPCR and HPLC, respectively. A predictive model for aflatoxin B1 synthesis in the initial ensiling phase was established, in function of grain moisture, external temperature, and time. Within the studied range, A. flavus’s initial concentration did not significantly influence aflatoxin B1 production. According to the model maximum aflatoxin production is expected at 30% moisture and 25°C temperature, after 6 days in the aerobic phase. Aflatoxin B1 production in such conditions was corroborated experimentally. Growth curves and aflatoxin B1 production highlighted that at 48 h of incubation under optimal conditions, aflatoxin B1 concentrations in mini-silos exceeded national legislation limits, reaching values close to 100 ppb. These results underscore the risk associated with A. flavus presence in ensiling material, emphasizing the importance of controlling its development in sorghum silos.
... Different combinations of predictor variables (fixed effects) were tested and compared using the Akaike information criterion (AIC). A model was considered prior if the difference in AIC value was >10, which represents a conservative interpretation of AIC 71 . As predictor variables, we used the variables listed in Supplementary Table 2. ...
Biological invasions are a growing challenge in a highly interconnected and globalized world, leading to the loss of native biodiversity. Indigenous peoples’ lands (IPLs) play a vital role in biodiversity conservation through activities such as land stewardship and management practices. Similar to protected areas, they are also often remote, with fewer connections to international trade networks. The extent to which IPLs are threatened by the spread of invasive species is still unknown. Here we provide a global study detailing the distribution and drivers of alien species on IPL. On average, IPLs host 30% (in absolute numbers: 11 ± 3.5) fewer alien species relative to other lands, after controlling for sampling intensities. Alien species numbers remained consistently lower on IPLs even after accounting for potentially confounding factors such as differences in accessibility and ecological integrity. The difference may result from land management practices of Indigenous peoples. In the relatively small number of cases where IPLs host disproportionately higher numbers of alien species than other lands, the most likely reason is high alien species propagule pressure arising from proximity to large urban areas. Overall, our results highlight the importance of IPLs in protecting nature in the face of increasing biological invasions.
... El mejor modelo será el que presente el menor AIC. Los modelos con una diferencia (ΔAIC) menor de 2 puntos respecto al modelo con menor AIC se considera que tienen un apoyo similar al del mejor modelo y permiten hacer inferencias respecto a la importancia de los factores físicos en la producción de brotes, hojas, raíces y la presencia de establecimiento (Burnham y Anderson, 2002). ...
The Ecological Park of Mexico City (PECM for its Spanish initials) plays an important role in the recharge of the aquifer in the southern area of Mexico City. Sedum oxypetalum is a dominant species in the preserved shrub of PECM and it probably plays an important role facilitating the establishment of late successional species. Given its poor germination, clonal propagation of S. oxypetalum has been used as a strategy to restore the disturbed areas in PECM. In this study I assessed the production of shoots, leaves, and adventitious roots, as well as the establishment of ramets of S. oxypetalum under the canopy of two potentially protective or nurse plants: Buddleia cordata and Opuntia spp. Furthermore, I evaluated the effects of the placement season (winter and summer), orientation, and physical factors (temperature, humidity, solar radiation and coverage of the nurse plant) in which the cuttings were placed. The results indicated that the presence of the protective plant is crucial for the production of shoots, leaves and roots, as it was observed that the stakes without protection presented very low values for these variables. The presence of a protective plant is also significant (p = 0.0147) for establishment, which showed a negative correlation with temperature. However, even under protective plants the total establishment was very low (2.86 %). The environmental factors that determined leaf production in ramets of S. oxypetalum were light and temperature, while moisture proved to have a strong effect on the production of the root tissue. Stakes placed in summer and below Opuntia presented higher values of production of shoots, leaves and roots, as well as the presence of establishment, but they did not last until the end of the annual cycle considered in this work, while the stakes placed in winter and below Buddleia did remain. Just as germination has massive establishment events, it is likely that there are events of mass establishment, with higher values than those observed in this experiment. I conclude that the presence of nurse plants is important for the clonal establishment of this species, but even under this protection a strategy based on the introduction of fragments of approximately 10 cm in length and 2 cm in diameter would be inefficient. Thus, it would be better as part of the strategies to restore the PECM, try to use stakes that are longer than 10 cm length and 3cm diameter, and to place them during winter under Buddleia´s canopy.
... We fitted models using maximum-likelihood methods in the nlme package (Pinheiro & Bates, 2000;Pinheiro, Bates, & R Core Team, 2023) in R (R Core Team, 2023). Given the relatively low sample sizes, we used a set of models with reduced parameters and the small sample size Akaike information criterion (AIC c ) for multi-model selection and inference (Burnham & Anderson, 2002). For a given set of models, we obtained Δ i as AIC ci ÀminAIC c , where minAIC c is the minimum AIC c from the model set, to calculate 'Akaike weights' for each model i. ...
Regular counts of walruses (Odobenus rosmarus) across their pan‐Arctic range are necessary to determine accurate population trends and in turn understand how current rapid changes in their habitat, such as sea ice loss, are impacting them. However, surveying a region as vast and remote as the Arctic with vessels or aircraft is a formidable logistical challenge, limiting the frequency and spatial coverage of field surveys. An alternative methodology involving very high‐resolution (VHR) satellite imagery has proven to be a useful tool to detect walruses, but the feasibility of accurately counting individuals has not been addressed. Here, we compare walrus counts obtained from a VHR WorldView‐3 satellite image, with a simultaneous ground count obtained using a remotely piloted aircraft system (RPAS). We estimated the accuracy of the walrus counts depending on (1) the spatial resolution of the VHR satellite imagery, providing the same WorldView‐3 image to assessors at three different spatial resolutions (i.e., 50, 30 and 15 cm per pixel) and (2) the level of expertise of the assessors (experts vs. a mixed level of experience – representative of citizen scientists). This latter aspect of the study is important to the efficiency and outcomes of the global assessment programme because there are citizen science campaigns inviting the public to count walruses in VHR satellite imagery. There were 73 walruses in our RPAS ‘control’ image. Our results show that walruses were under‐counted in VHR satellite imagery at all spatial resolutions and across all levels of assessor expertise. Counts from the VHR satellite imagery with 30 cm spatial resolution were the most accurate and least variable across levels of expertise. This was a successful first attempt at validating VHR counts with near‐simultaneous, in situ, data but further assessments are required for walrus aggregations with different densities and configurations, on different substrates.
... The parameter estimates from the best-scoring replicate (with the highest log-likelihood) were used to seed searches in the next round. The best model was selected based on the lowest Akaike information criterion (AIC), and we calculated Akaike weights (ωi) among the seven models tested per population pair to evaluate the relative likelihood of each model in a multimodel approach (Burnham & Anderson, 2002). We selected the model with the highest Akaike weight as the best model. ...
Seed dispersal is crucial for plants to colonize new habitats and facilitate gene flow between populations. However, Pleistocene extinctions of large-bodied fruit-eating and seed-dispersing animals, known as 'megafrugivores', may have hindered the dispersal of plants with large fruits (> 4cm fruit length-'megafruits'). Plants with megafruits are common across the flora of Madagascar, especially within the palm (Arecaceae) family. This dissertation investigates the macro-ecological and micro-evolutionary consequences of dispersal limitation on palms with megafruits in Madagascar. Specifically, I investigated three key aspects: (i) turnover or beta-diversity of palms on Madagascar and the distribution of their dispersal-related traits, (ii) the genetic diversity and genetic structure of three palms with megafruits compared to one palm with small fruits, and (iii) population size and migration rates changes over time of several Malagasy palm species with different ecological characteristics. To address these questions, historical ranges of extinct megafrugivores were reconstructed based on fossil sites, and data on extant frugivores, human activities, and climate were collected. Fieldwork in Madagascar provided genetic data for 12 palm species across 46 populations, from which I generated double digest restriction-site associated DNA sequencing data. Various interdisciplinary methods were employed, including redundancy analyses, variation partitioning, linear mixed effect models, species distribution models, and demographic modelling. The findings indicate that the current turnover of palms in Madagascar is primarily influenced by extant frugivores and climate, with limited impact from extinct frugivores. Surprisingly, there is no evidence of decreased genetic diversity or increased genetic differentiation in megafruited palms due to the loss of their megafrugivore dispersers. Genetic diversity is positively associated with human population density but negatively influenced by road densities, possibly reflecting habitat fragmentation by humans. Connectivity between populations is linked to the number of shared extinct and extant (mega)frugivore species, for megafruited and small-fruited palm populations, respectively. This highlights the importance of past long-distance dispersal events by megafrugivores and human-mediated dispersal possibly maintaining connectivity for megafruited palms. Population declines are observed across palms since the Last Glacial Maximum, particularly in humid forest species rarely used by humans, while humid forest species with megafruits show recent migration disruption. In contrast, palm species with smaller fruits that are highly used by humans show less pronounced declines and more stable historical migration rates. Overall, this dissertation illustrates that while the role of megafrugivores as seed dispersers is still evident on the genome of megafruited palms, other factors such as human-mediated dispersal and climate have an influence over the distribution, genetics and demographic histories of palms in Madagascar. It further shows how integrating genetic data with ecological data on species distributions, climate, human activities, can provide novel insights into the drivers of different facets of biodiversity of such a diverse group of plants such as palms. 5
... By adding or removing predictors, it generated all possible combinations of candidate models. The model with the lowest AIC value and thus the highest Akaike weight was considered to be the best and the most parsimonious (Burnham and Anderson 2002). ...
Breeding success of birds depends on survival during two critical stages of the reproductive period: First, egg laying and incubation, and then nestling and fledgling. This essential element of avian life history mirrors an evolutionary adaptation of parents to existing environmental conditions. The main factors that determine nest survival involve weather, predation and sibling competition. Despite numerous studies documenting their impact on breeding success, only a few have analysed the issue with regard to ground-nesting birds and estimated their survival functions. Therefore, we decided to examine nest survival probability of the Crested Lark ( Galerida cristata ) in a population that occupies newly established roadside habitats in Central Poland. The analysis is based on 141 nests monitored between 2018 and 2022. We found that the mean survival probability of the whole nesting period was 0.376, and it was higher during the egg stage (0.836) than during the nestling period (0.392). The Cox proportional hazards model shows that nest survival in the nestling stage is mainly affected by the time of breeding and the distance from the road edge, and also by mean temperature of the whole nesting period. In other words, the probability of a brood failure in the nestling stage decreases as the breeding season advances, whereas it increases among nests located closer to the road edge. Furthermore, during the whole nesting period, nest failure decreases as the temperature rises. Our study suggests that the Crested Lark, being a multi-brood and thermophilic species inhabiting temperate regions, may benefit more if its nesting attempts begin later during the season when breeding conditions become more favourable. However, we also take into consideration a hypothesis that nesting in grassy habitats near road edges may prove to be an ecological trap, attracting high densities of nesting birds but leading to their low nest success.
... Given that the WAIC was unstable, we calculated the conditional deviance information criterion (DIC) proposed by Celeux et al. (2006), with DIC determined based on the conditional likelihood. Similarly, for other model selection procedures, the top model among the four models (developed from a priori hypotheses) with a DIC less than 4 was considered to be plausible, and the degree of evidence supporting one model over another was calculated from deviance weights (i.e., Akaike weights based on DIC statistics; Burnham and Anderson 2002). ...
Objective
In 2000, the Laguna Atascosa National Wildlife Refuge acquired the Bahia Grande (Texas) management unit, a space that had lain barren and arid for 70 years. A large cooperative partnership launched a restoration project to replenish the basin and recover its original tidal hydrology. In 2005, the construction of a pilot channel successfully restored water throughout the basin, and plans to eventually widen the channel were developed. Our study aims to evaluate an estuarine habitat restoration by assessing ecological drivers and the impacts on species diversity.
Methods
We evaluated species richness, detection/occupancy rates, and species–habitat relationships, and we estimated the sampling effort required to achieve a given level of relative precision if relative abundance was used instead of occupancy to inform future sampling. Sampling gear included bag seines for juvenile life stages and gill nets for capturing subadult and adult life stages. For analysis, we used a Bayesian negative binomial linear mixed‐effects model to evaluate richness–habitat relationships and a hierarchical Bayesian multispecies model to evaluate individual species–habitat relationships, and we calculated the total number of fish captured and relative standard error by gear and sample year to produce a precise estimate of relative abundance.
Result
Overall, 29 species were caught between 2018 and 2021. Salinity emerged as a clear driver in the Bahia Grande, as both species richness and individual‐level responses were negatively associated with high salinity values. We found that catch estimated as relative abundance had much variability, as is typical of most survey programs assuming constant detectability, and the number of net sets or seine hauls required to achieve a given level of relative precision varied considerably depending on the species, season, year, and gear type. The most collected species were found in the upper extremes of their salinity tolerances—potentially a unique adaptation to this hypersaline system.
Conclusion
Baseline data suggest that for the channel widening to be successful, there must be a noticeable increase in suitable habitat characteristics throughout the basin.
... Simpler models also allow for rapid processing times which allows the decision-making process to move forward without delay (Conroy and Peterson, 2013). Individual based models, such as the Rose/ Smith delta smelt model, are typically unwieldly (e.g., sensitivity analysis took more than 3 weeks on 4 computers) and often contain multiple uninfluential parameters and associated uncertainties that greatly inflate the variability of predictions (e.g., the bias-variance tradeoff; Burnham and Anderson, 2002). We do not mean to imply that complex models do not serve a useful purpose, but models for conservation decision-making should chiefly aim to help stakeholders think about and communicate hypotheses concerning conservation problems (Phillips, 1982, 1984, Starfield, 1997Peterson and Duarte, 2020). ...
A structured decision making (SDM) approach can help evaluate tradeoffs between conservation and human-benefit objectives by fostering communication and knowledge transfer among stakeholders, decision makers, and the public. However, the process is iterative and completing the full process may take years. It can be difficult to initiate an SDM effort when problems seem insurmountable. Occasionally, SDM may not even be the best or correct approach for addressing the conservation problem at hand. We describe the implementation of an SDM process to help inform difficult decisions related to competing objectives. We convened a diverse stake-holder group from the largest estuary in the western United States; the San Francisco Bay and Sacramento-San Joaquin Delta (Bay-Delta). The stakeholder group consisted of representatives from local, state, and federal agencies, non-profit organizations, and recreational fishers. The stakeholder group agreed on a problem statement and identified four priority objectives related to Chinook salmon, delta smelt, water availability and reliability, and agricultural water use. Furthermore, they proposed 14 candidate management actions to achieve their objectives. The group then used existing quantitative models and data to evaluate trade-offs in proposed management actions to identify areas of agreement of proposed candidate actions. The clear communication of the problem statement and objectives among the stakeholder group, along with evaluation of tradeoffs and uncertainty via decision-support models suggest that a full SDM approach may work in the Bay-Delta. We further communicate lessons learned during our implementation of SDM to help guide future SDM efforts in the region and elsewhere.
... To examine whether the urbanization score correlates with lapwing BTs even when assessed under controlled conditions (H2, our main hypothesis), we used general linear mixed models (GLMMs) in a model comparison framework (Beier et al., 2002). The dependent variables were the binomial LTE and the PC values during the OFT and CST assays (PC1 and PC2 for each assay: calmness, mobility, conspecific calm level and conspecific tolerance), modelled with a Gaussian link function. ...
Urbanization imposes significant challenges upon wildlife worldwide, highlighting the need to understand how species and individuals respond to urban environments. Because animal behaviour is not fully plastic, these behavioural responses may also reflect consistent differences between individuals (behavioural types, BTs), or affect the covariation of different BTs in the population (behavioural syndromes , BSs). Here, we focused on the spur-winged lapwing, Vanellus spinosus, a common resident occupying diverse habitats. We caught breeding lapwings from sites throughout central and northern Israel and calculated their urbanization scores (built-up area around the nest). In an aviary, we subsequently performed three commonly used behavioural assays: (1) 'latency to emerge', (2) 'open-field' test and (3) respond to conspecific model. We repeated the sequence three times at weekly intervals. After determining that behaviours were indeed repeatable (i.e. they establish BTs), and reducing dimensions through principle component analyses, we found that the behaviours observed during both the 'open-field' and the 'response to conspecific' assays were affected by the interaction between an individual's sex, body condition and urbanization score. Lapwings from more urban areas displayed stronger sex-dependent behaviours (with urban males being calmer in the 'open-field' test and more tolerant of the conspecific threat compared to urban females). Finally, urban lapwings showed stronger BSs than nonurban ones, with stronger covariation between their latency to emerge and calmness BTs during the two subsequent assays. Overall, our study sheds light on the patterns of behavioural changes associated with urbanization, demonstrating how both the behaviours themselves (BTs) and their dependencies (BSs) may be influenced, while also highlighting the potential interaction of behavioural changes with individuals' physiological condition and sex. Such detailed knowledge can inform mitigation strategies of the issues encountered by wild animals inhabiting urban areas, and to understand why some species are more resilient to urbanization than others.
... We tested model goodness of ft via the χ 2 method, comparing the χ 2 statistic for model deviance to that of the null model [30]. We compared models by change in Akaike Information Criterion scores (Δ AIC) [31] for selection of the individually best-ftted model by timeframe. We interpreted selected model slopes by odds ratio, with probability of consumption reported for each of the size classes. ...
Black carp Mylopharyngodon piceus (Richardson, 1846) have been widely used as biological control of snails in aquaculture and were imported to the United States in the 1970s and 1980s for this purpose. Prior research emphasizes the species’ propensity to control gastropods, but since subsequent escape and establishment of black carp in portions of the Mississippi River Basin, concerns now focus on the numerous endangered and endemic bivalve species upon which black carp may predate. Black carp mouth gape may limit predation on larger bivalves, but bite force is also a factor. We used regression of fish length to mouth gape of wild-caught black carp and compared these results to tank forage size preference trials with bivalve prey Corbicula fluminea clams. Wild-caught black carp ranged from 429 to 1580 mm total length, a size range larger than measured in previous studies. Regression of fish length and mouth gape indicated greater variability among sizes, as expected from wild versus cultured populations. Clam consumption was size-dependent. Black carp commonly engulfed but did not consume the largest clams in tank feeding trials. Shell width was a better predictor of successful consumption than length or height. Predation was restricted at sizes less than the mouth gape of test black carp as observed by individuals engulfing but failing to consume prey. This result indicates that either bite force or the pharyngeal apparatus gape (i.e., the distance between the pharyngeal teeth and keratinous pad) limited successful crushing of engulfed shells. Bivalve predation by black carp is limited by both a fish’s ability to engulf prey and the ability to fracture the shell of larger prey items that cannot be broken or swallowed whole. The results of this research may be used to assess potential prey sizes of wild black carp and anticipated effects of predation on bivalve communities.
... In the final component of our analysis, we compared a series of candidate models containing territorial and social information, as informed by the previous two steps, to test our predictions (see Table 1) on pack resource selection and movement behavior relative to territorial and social contexts of conspecifics. Our step-wise approach avoids having to use model selection on one very large model that could lead to spurious results (Burnham & Anderson, 1998), and has been successful in other studies which (1) compare several spatiotemporal resolutions of landcover data (Nisi et al., 2022;Zeller et al., 2017) and/or (2) want to control for expected habitat use (e.g. finding a "base" model) while testing other ecological hypotheses (Davies et al., 2021). ...
While territoriality is one of the key mechanisms influencing carnivore space use, most studies quantify resource selection and movement in the absence of conspecific influence or territorial structure. Our analysis incorporated social information in a resource selection framework to investigate mechanisms of territoriality and intra‐specific competition on the habitat selection of a large, social carnivore. We fit integrated step selection functions to 3‐h GPS data from 12 collared African wild dog packs in the Okavango Delta and estimated selection coefficients using a conditional Poisson likelihood with random effects. Packs selected for their neighbors' 30‐day boundary (defined as their 95% kernel density estimate) and for their own 90‐day core (defined as their 50% kernel density estimate). Neighbors' 30‐day boundary had a greater influence on resource selection than any habitat feature. Habitat selection differed when they were within versus beyond their neighbors' 30‐day boundary. Pack size, pack tenure, pup presence, and seasonality all mediated how packs responded to neighbors' space use, and seasonal dynamics altered the strength of residency. While newly‐formed packs and packs with pups avoided their neighbors' boundary, older packs and those without pups selected for it. Packs also selected for the boundary of larger neighboring packs more strongly than that of smaller ones. Social structure within packs has implications for how they interact with conspecifics, and therefore how they are distributed across the landscape. Future research should continue to investigate how territorial processes are mediated by social dynamics and, in turn, how territorial structure mediates resource selection and movement. These results could inform the development of a human–wildlife conflict (HWC) mitigation tool by co‐opting the mechanisms of conspecific interactions to manage space use of endangered carnivores.
... In a second step, the probability of nest detection was estimated using seven models combining probability density function with adjustments. The model with the lowest Akaike's Information Criterion (AIC) was selected for each sampling zone unit [7]. ...
The distribution of Orangutans has not been accurately mapped, as forest habitat is extensive and there is limited access to remote forests such as upland and swamp forest. The main objective of this study is to map the distribution density of Orangutans in seven key habitats using spatial modeling, which includes (i) investigating the relative abundance of Orangutans in different habitat types and terrain altitude, and (ii) investigating the factors that could influence an estimation of the Orangutans population. Based on these findings, potential conservation strategies are determined and discussed in this paper. In this study, distribution and density patterns for forest areas were determined, along with abundance of different forest types and altitude. Observations of nest production rates and nest decay rates were carried out. A series of aerial surveys, covering seven key Orangutans forest habitats, were conducted between 2007 and 2010 to map the spatial distribution. A ground survey followed in each forest habitat. Based on the aerial survey, it was demonstrated that the Orangutans distribution is not evenly spread. A line-transect nest-count methodology was also used to calculate the Orangutans population based on each spatial digital distribution zone. In short, this study provides an estimation of the conservative population size of Orangutans in each forest habitat.
... The fit of each model was checked by using the Akaike Information Criterion corrected for small sample size (AICc; Burnham and Anderson 2002 ). A difference of more than two points from the model with the lowest (best) score is considered to show that the model with the highest (poorest) score is a considerably poorer fit to the data (Akaike 1971 , Cavanaugh andNeath 2019 ). ...
With a biomass of ∼4 million tonnes, and annual catches of 900 000 tonnes, the northeast Atlantic (NEA) cod stock in the Barents Sea is the world’s largest. Scientists have been trying to explain the variability in recruitment of this stock for over 100 years, in particular connecting it to spawning stock biomass and environmental factors such as temperature. It has been suggested that the combination of ocean acidification and global warming will lead to a significant decrease in the spawning stock biomass and an eventual (end of this century) collapse of the NEA cod stock in the Barents Sea. We show that a temperature- and OA-driven decline in recruits will likely lead to a smaller cod stock, but not to a collapse. Instead, the level of fishing pressure and, not least, the choice of the recruitment function applied in simulations and how it relates to temperature, is extremely important when making such forecasts. Applying a non-linear relationship between temperature and spawning stock biomass—as has been done in studies that predict a collapse of the NEA cod stock—does not improve accuracy and, in addition, adds a large decrease in number of recruits that is not biologically supported.
... To interpret the coefficient, we have used the Parsimony principle (The parsimony principle is the simplest scientific explanation for the data. For details, refer to Ref. [67]) and considered it to represent "high volatility" compared to the average. It is worth noting that none of the existing literature has been able to define a specific range for this coefficient. ...
... We constructed a candidate model set for each response variable (see Table A4). We compared the relative strength of support for the inclusion of each environmental factor using Akaike's Information Criterion and Akaike weights (w i ) to rank models (Burnham and Anderson, 2002;Carreira et al., 2023). Our predictor variables included the number of oil wells within 10 km of the PMD deployment site, burn percentage in the previous year, and snow water equivalent (referred to as snowmelt from this point forward). ...
... With the resulting set of variables, we evaluated different Maxent models by using four regularization numbers ranging from 0.5 to 2 with steps of 0.5 (Elith et al., 2011). The model with the highest performance was selected based on the Akaike Information Criterion (AICc) (Burnham and Anderson, 2002). We ran MaxEnt with the best set of predictor variables selected through this procedure and computed ten replicates to average the results using the cross-validation method (He et al., 2022). ...
Our study focused on analysing the distribution factors of the Asiatic Cheetah's main prey species, including the Wild Goat (Capra aegagrus), Urial (Ovis vignei), Goitered Gazelle (Gazella subgutturosa), Jebeer Gazelle (Gazella bennettii), and Cape Hare (Lepus capensis) in the Turan Biosphere Reserve (TBR), a critical Cheetah habitat in Iran
... Among the 8 independent variables, those identified as having a significant effect (q-value: p < 0.05) by the factor detector of the Geo-Detector model were further analyzed to assess the driving patterns of differences in the distribution of ARGs. Linear were chosen to fit two-variable on the R 2 (Burnham, 2002). The Analysis of Similarities (ANOSIM) was utilized to assess whether there are disparities in ARG distribution caused by environmental media types (water vs sediment) with "vegan" package in R software. ...
... This operation only occurred in the three best models (Temp in BWL when predicting k , Temp and TempV in TMS when predicting S , and TempV and Cover in EMS when predictingS ). As the extent of the significance matched well with the value of the weight (Table S2), we used the latter to represent the relative importance because full model averaging optimizes the uncertainties and biases from threshold-selected models (Burnham and Anderson 2002). Since the data of Tree, edaphic factors, Mois, and MoisV were unavailable in EMS, we removed EMS and focused on 9 mountains when comparing the relative importance of each factor in decomposition. ...
Forest litter decomposition is considered as an essential ecosystem process affecting carbon and nutrient cycling in mountains. However, there exists high uncertainty in accurately estimating the contribution of litter decomposition to terrestrial ecosystems, largely due to the incomparability of different studies and the data limitation in microclimate and non-climatic factors at spatially matched scales. Here we used the tea bag index (TBI) as a standardized protocol to evaluate spatial variations in forest litter decomposition rate (k) and stabilization factor (S) across 10 mountains spanning a wide range of subtropical and tropical forests. Based on the coordinated experiment of 6,864 teabags in 568 sampling sites along elevations, we evaluated the importance of 10 environmental factors covering soil microclimate, edaphic properties, plant diversity, and topography on k and S by using model averaging and linear-mixed effects models. Of the 10 mountains, we found a consistently decreasing pattern of k and an increasing pattern for S along elevations. And the significant effect of k with elevation was mainly found in the western and northmost mountains, while the effect of S occurred in the western and southernmost mountains. For microclimate, there was a general importance of soil temperature (coef. = 0.48) and temperature variation in the growing season (coef. = 0.36) in k, and soil temperature (coef. = -0.46) and moisture variation on S (coef. = -0.36). The dominant role of soil microclimate was mainly found in western mountains with relatively cold environments. For non-climatic drivers, a significant effect of tree diversity on k and a negative correlation of edaphic and topography with S in the western and southern mountains were detected. These findings provide a general understanding of spatial variations of driving factors in forest litter decomposition and highlight a dominant control of soil microclimate in cold forests in high elevations and latitudes.
... for all outcomes when tested in both Models 1 and 2 (Hu & Bentler, 1999). The Akaike information criterion and Bayesian information criterion values were lower for Model 1 than Model 2 for all outcomes (Burnham & Anderson, 1998). As such, then, Model 1 provided a better fit of the data, meaning maternal competitiveness fit better as a predictor WAGSTAFF, WOLF, AND SMITH of social comparison and social media use, than as an outcome of these. ...
Maternal competitiveness requires that mothers engage in a process of social comparison, and social media may facilitate this competition. However, social media may also perpetuate an unrealistic ideology about motherhood, which can have negative effects on well-being when mothers inevitably fail to stack up. To date, however, these relationships have not been explored. To test these relationships, participants consisting of 252 mothers (Mage = 31.50, primarily from Australia) completed an online survey. We found maternal competitiveness increased social comparison tendencies which subsequently increased investment in Instagram as well as internalization of intensive mothering ideology. Social comparison had both direct and indirect effects on well-being. Internalization of an intensive mothering ideology does not appear to be dependent on investment in social media, specifically. Overall, these results have theoretical implications for our understanding of the role of maternal competitiveness in social comparison, social media use, and maternal well-being.
... Models with smaller AIC and CV1 values typically fit the data better than models with larger values. Burnham and Anderson (2002) recommend investigating all models that have AIC values less than minimum AIC + 2. ...
... The capture rate (captures/net meters-hour) was modeled using negative binomial models for each species. A set of two candidate models was designed for model selection based on AICc (Burnham and Anderson 2002) to quantify the effect of EMC on capture rate. The first model only included the effect of dispersal intensity (observed transient individuals divided by the visual count effort in time) on capture rate (H 0 ), while the second model included both the dispersal intensity and the enhanced capture effort (H 1 ). ...
... Therefore, we constructed a set of candidate models excluding those models which contained both variables simultaneously. Models were compared using Akaike's information criterion correcting for small sample size (AIC c ) (Burnham and Anderson 2002). Hierarchically, ...
Birds often have to choose their nest site location along a food safety axis, balancing nest predation danger with the food requirements of themselves and their offspring. This is probably most important for precocial species, such as most shorebirds, in which both chicks and parents need access to food resources in the surroundings of the nest, at least during the first days of life of the chicks. In many Arctic ecosystems, shorebird nests are typically prone to predation by both avian and terrestrial predators, especially in lemming-poor years. Among other factors, the strength of the trophic interactions between shorebirds, their prey, and their predators depend on how all of these are distributed across space. During two breeding seasons in northern Taimyr, North-Central Russia, we investigated how the spatial distribution of red knot Calidris canutus and little stint Calidris minuta nests and broods overlaps with the local food landscape and also with the distribution of avian predators and their main prey, lemmings. We found that the two shorebird species use different habitats that vary in arthropod community structure in accordance with the birds’ diet: while little stints selected lower elevations where chironomid midges Chironomidae are more abundant, red knots selected higher elevations where crane flies Tipulidae are more abundant. Furthermore, little stints share low-elevation habitats with lemmings and predators, while red knots inhabit higher elevations averted by both lemmings and avian predators. We found higher nest predation for little stint nests than for red knots nests, especially in a low-lemming year. Our results thus support the idea that food web interactions are driven by landscape and community aspects.
... As response variables, we considered: sampled taxonomic richness and the three Fric values mentioned above. Data from all the variables were transformed (log10 + 1), and we utilized the lowest Akaike Information Criterion, AIC (Akaike 1974) value to determine which model best explained the behavior of the response variable (Burnham and Anderson 1998). We used JMP Pro 14 software (www. ...
We characterize the taxonomic and functional diversity of waterbird communities in mangrove forests of 23 coastal lagoons in the southern Mexican Pacific coast, to evaluate the hypothesis of decline of taxonomic and functional richness of waterbird communities in the face of loss of natural habitat cover and increased fragmentation. We quantified patterns of land use cover, considering the heterogeneity of natural and anthropized vegetation cover as a proxy for human-caused fragmentation, and used generalized linear models to explore the relationship between these two covers with the taxo- nomic richness and functional richness of bird communities. Results show that both aspects of biodiversity positively relate to larger natural habitat areas, while higher fragmentation values have a negative effect on them. Our results sug- gest that habitat loss and fragmentation of vegetation cover negatively affect the diversity of waterbird communities and can compromise their link to ecosystem functioning processes in coastal lagoons, by decreasing their functional diversity.
The study aimed at evaluating the effects of student-centered teaching methods on teachers' self-efficacy in ten selected Senior High School in the Accra Metropolis of Ghana. To accomplish the main objective, the study specifically sought; identify the teacher's favorite student-centered teaching technique at Accra Senior High School; eachers' perceptions of the considerable advantages of using student-centered teaching approaches; the relationship between teacher demographics and self-efficacy and the impact of student-centered teaching on teacher self-efficacy. The study adopted the quantitative research approach for the study. A total of 200 teachers were purposively chosen for the study. The study found that that teacher preferred to use student-centered teaching methods such as Role-playing, brainstorming and discussion, demonstrations, and simulations, activity-based teaching, cooperative and collaborative learning, debates, field trips and projects in teaching students. The study found that the use of student-centered teaching method helps students to have a higher and longer retention level, helps students to have in-depth understanding of subject matter, helps students to acquire inventive problem-solving skills, helps students to acquire increased opportunities to demonstrate mastery of subject matter, helps to involve students to use their higher imaginative skills to solve problem and also, enables students become further self-determining and independent self-leaners in their learning. The study found no significant difference between teachers' gender and their self-efficacy. However, there exist a significant difference between teachers' working experience and their self-efficacy belief in the use of student-centered teaching methods in teaching students in the Accra metropolis of Ghana. The study found significant effect of teachers' student-centered teaching method on teacher' efficacy in students' engagement, classroom management and instructional strategies.
This study's general objective is to investigate the effect of classroom management on students' stress level in Ghana: a case of senior high schools in the Kumasi Metropolis, Ghana Four research questions were designed for study, first, determining the perceived amount of stress experienced by high school students, reasons of high school pupils' stress levels as perceived by teacher, whether teachers' classroom management has a substantial and beneficial effect on high school pupils' stress levels and the stress coping tactics used by instructors to help high school pupils in Ghana's Kumasi Metropolis cope with stress. The study adopted the quantitative research approach for the study. The researchers collected data quantitatively via the use of the descriptive research approach. Therefore 365 teachers and 314 students were sampled from the six senior high schools. The study adopted the proportionate random sampling was employed to proportionately distribute the total sample size among the six senior high school used. The study found a statistically significant between teachers' classroom management dimensions in terms of personal management, teaching and learning and discipline. The study asserted that teaching and learning significantly contributes to students' stress level by almost 67%. There is a need for teachers to reconsider the kind of teaching and learning environment they create for students and hence, reduce students' workload if possible or establish good rapport with them so as to reduce their stress level. The study further revealed a need for stress coping strategies to be implemented by students to reduce their high stress levels in the classroom. It was recommended to teachers and students benefit from induction and mentorship programs. Programmes aimed to improve student behavior and social and emotional learning (SEL) benefit instructors and boost classroom learning. Stress and mindfulness-based professional development workshops should be organized for both teachers and students to help them maintain and increase their attention.
Education is the key agent of sustainable growth change. It enhances the ability of people to turn their social dreams into reality. In their sustainable development every country strives for high quality education. The value of digital game based learning for shaping children's success in schools worldwide has been highlighted. This research therefore examined the impact on the academic performance of students from digital game-based learning in Low School Divisions to High School Division in Some Selected Schools in Kumasi Metropolis. A descriptive survey was used in the study. The target population in the Kumasi metropolis was 2,000 students. The study included a number of 200 students in Kumasi Metropolis who were chosen using a multi-stage sampling process, from low school to high school. The student survey was used to collect data. The data was then analyzed statistically and reported in terms of frequency, mean, and standard deviation. SPSS, a statistical package for social sciences, was used to aid in the creation of a table summarizing the findings. Students' academic progress is influenced by a combination of digital game-based learning, parents' schooling, and parents' professions. The findings, however, show that a student's academic achievement is not significantly influenced by his or her parents' financial level. Students' academic achievement was shown to be significantly impacted by game-based learning's digital elements.
Aims
The artificial cultivation of cyanobacterial crusts represents a novel technique for sand stabilization. Herbaceous plants are the main components of desert biodiversity and are important for ecological restoration efforts in dryland areas. However, there is a lack of research on the interaction between artificially-cultivated cyanobacterial crusts and herbaceous plant diversity.
Methods
Artificially-cultivated cyanobacterial crusts were monitored for three years after inoculation, as well as the composition, growth and diversity of associated herbaceous plant communities.
Results
(1) The percent cover, thickness, and chlorophyll a content of the artificially-cultivated cyanobacterial crusts gradually increased over time, with the chlorophyll a and exopolysaccharide content eventually matching that of eleven-year-old naturally-developed biological soil crusts. (2) Ten herbaceous species belonging to five families and ten genera were identified in association with the artificial cyanobacterial crusts, and herb cover, biomass, richness and abundance generally increased over time with significant differences among years(P < 0.05). (3) Correlation analyses revealed that the relationship between the artificial cyanobacterial crust and herbaceous plant communities shifted from positive to negative over time.
Conclusion
Artificial cyanobacterial inoculation fostered the co-development of biocrusts and herbaceous plants, potentially accelerating the recovery of desert ecosystem functions. This study provides a theoretical basis for the further promotion and large-scale application of artificially-cultivated cyanobacterial crusts.
Urban areas form a complex, heterogeneous, fragmented mosaic of habitats, including ecosystems in different degrees of alteration. Nevertheless, some species of birds of prey can thrive in cities. But, there is a knowledge gap regarding the species of birds of prey that who inhabit the cities in Chile, especially those that reproduce in it. Hence, we work in Valdivia, a city that preserves an important natural matrix. The object of this study was to characterize the diversity, abundance, and nest sites of diurnal and nocturnal raptors in the urban area of a city in southern Chile. Twelve species of raptor were recorded, seven diurnal and five nocturnal, 63.1% of the species expected for neighboring rural areas. Twenty-seven nesting sites were recorded two of diurnal raptors and four nocturnal raptors. The availability of nesting sites close to feeding sites, distance to houses, and grassland-shrub cover are essential factors for the success of raptor populations. Cities like Valdivia could offer suitable nesting sites for reproduction, helping to restore habitats for birds of prey.
Discerning assimilated diets of wild animals using stable isotopes is well established where potential dietary items in food webs are isotopically distinct. With the advent of mixing models, and Bayesian extensions of such models (Bayesian Stable Isotope Mixing Models, BSIMMs), statistical techniques available for these efforts have been rapidly increasing. The accuracy with which BSIMMs quantify diet, however, depends on several factors including uncertainty in tissue discrimination factors (TDFs; Δ) and identification of appropriate error structures. Whereas performance of BSIMMs has mostly been evaluated with simulations, here we test the efficacy of BSIMMs by raising domestic broiler chicks (Gallus gallus domesticus) on four isotopically distinct diets under controlled environmental conditions, ideal for evaluating factors that affect TDFs and testing how BSIMMs allocate individual birds to diets that vary in isotopic similarity. For both liver and feather tissues, δ¹³C and δ ¹⁵N values differed among dietary groups. Δ¹³C of liver, but not feather, was negatively related to the rate at which individuals gained body mass. For Δ¹⁵N, we identified effects of dietary group, sex, and tissue type, as well as an interaction between sex and tissue type, with females having higher liver Δ¹⁵N relative to males. For both tissues, BSIMMs allocated most chicks to correct dietary groups, especially for models using combined TDFs rather than diet-specific TDFs, and those applying a multiplicative error structure. These findings provide new information on how biological processes affect TDFs and confirm that adequately accounting for variability in consumer isotopes is necessary to optimize performance of BSIMMs. Moreover, results demonstrate experimentally that these models reliably characterize consumed diets when appropriately parameterized.
Bottomland hardwood (BLH) forest ecosystems within the Lower Mississippi Alluvial Valley exist in narrow corridors composed of frequently flooded mature forests and complemented by afforested younger forest patches due to BLH afforestation efforts. Sylvilagus aquaticus (Swamp Rabbit), a BLH forest-specialist species, require a diversity of habitat conditions, but little information exists on fine-scale Swamp Rabbit use of mature and young forest habitats and the conditions that may influence Swamp Rabbit habitat use. We addressed this literature gap by assessing use of habitat by Swamp Rabbits in af-forested and mature BLH stands in southern Illinois during March 2014-March 2016. At 746 plots (area = 3.15 m², 60 m x 60 m spacing), we used Swamp Rabbit fecal pellets to quantify Swamp Rabbit habitat use and identified 9 habitat variables known to be important to Swamp Rabbits. We then created 18 a priori generalized linear models to evaluate variation in Swamp Rabbit habitat use relative to habitat variables each study year. Individual forest stands strongly influenced Swamp Rabbit habitat use in all 3 study years in addition to macro-habitat variables (i.e., distance to water, distance to afforested-mature stand interface) and micro-habitat variables (i.e., woody stem density, herbaceous ground cover) in some years. We found that both mature and afforested stands were used by Swamp Rabbits but that edaphic conditions specific to stands likely affected flooding and water inundation in localized areas impacting habitat conditions and thus Swamp Rabbit use. While we found increased ground vegetation and woody stem density had positive impacts on habitat use by Swamp Rabbits in 2014, these variables were no longer significant predictors of Swamp Rabbit occupancy when flooding was severe in 2015 and the following year, 2016. These results point towards water inundation from flooding as the main driver of Swamp Rabbit habitat use when it limits terrestrial habitat and the availability of vegetation resources important for food and hiding cover. Because Swamp Rabbit habitat use is driven by habitat at the stand scale, habitat management can focus on managing stands with more consistently dry conditions to provide all necessary habitat elements when lower elevations are unavailable due to inundation. This research underscores the annual variability of these forest ecosystems and the importance of incorporating forest vegetation dynamics, hydrogeomorphology and flooding incidence and severity into management plans for Swamp Rabbits.
Examining the distribution patterns and spatiotemporal niche overlap of sympatric species is crucial for understanding core concepts in community ecology and for the effective management of multi-species habitats within shared landscapes. Using data from 26 camera-traps, recorded over two years (December 2020–November 2022), in Sidi Toui National Park (STNP), Tunisia, we investigate habitat use and activity patterns of the scimitar-horned oryx (n = 1865 captures) and dorcas gazelle (n = 1208 captures). Using information theory and multi-model inference methods, along with the Pianka index, we evaluated the habitat characteristics influencing species distribution and their spatial niche overlap. To delineate daily activity patterns, we applied kernel density estimation. Our findings indicate minimal spatial overlap and distinct environmental factors determining suitable habitats for each species. Furthermore, we found significant temporal niche overlaps, indicative of synchrony in daily activity patterns, with both species showing peak activity at dawn and dusk. Our results indicated that oryx and gazelle differ in at least one dimension of their ecological niche at the current density levels, which contributes to their long-term and stable coexistence in STNP.
The title of this article is (essentially) the same as the famous paper Basu (2011b). Basu often opined that counterexamples were the best way to learn limitations of theories or methods and I have followed his directive in my own teaching. A number of counterexamples I use extensively in teaching are collected here.
The Gran Canaria Blue Chaffinch is the rarest forest passerine in the western Palaearctic with a population reduced to a single locality, Inagua, in the west of the island. After a forest fire, some birds were established in another location and a reinforcement programme was launched with the aim of consolidating this new population. Between 2010 and 2019, 194 Blue Chaffinches were released in the pine forest of La Cumbre, in the centre of the island and at a higher altitude than the previous one. Birds of two origins were used for this action: captive-bred birds were released using “soft” release methods, and wild-caught birds from the Inagua source population were released using “hard” release methods. Survival of radio-tagged birds (20–42 days of battery life) was high and similar between the two groups. Wild-caught birds occupied 12–15 times more surface area than captive-bred birds that remained close to supplementary feeding sites. All translocated birds displayed breeding behaviour in the following breeding season, although the rate of contribution to the new population was significantly lower for wild-caught birds (21% compared to 54% for captive-bred birds). This disparity can be partly attributed to nearly one-fifth of the wild-caught birds returning to Inagua. We conclude that the establishment phase of the Blue Chaffinch reinforced program in Gran Canaria has been successful. To retain wild-caught birds and deter their return to the source population, we recommend employing methods akin to the soft-release techniques utilized for captive-bred birds. Ongoing monitoring of the enhanced population, collecting data on survival and breeding success, will enable the evaluation of the long-term success of the translocation program.
Soybean (Glycine max) is among the most important field crops in the world, and the USA is a top global producer, but USA soybean losses have increased because of multitude of factors, including wildlife damage. Although small, terrestrial rodents (Order: Rodentia) are capable of causing substantial damage to soybean and other field crops. Consequently, methods need to be developed that can provide agricultural producers and wildlife managers with accurate information about rodent populations at the field-level. We conducted a multi-site, before-after-intervention study in the midwestern USA to evaluate the effectiveness of varying treatment timings for cover crop reduction/removal prior to soybean planting, which was previously posited as an effective non-lethal approach for reducing rodents in soybean fields and mitigating crop damage. We chemically treated cover crops immediately (control), at two-weeks, and at four-weeks in four fields prior to soybean planting and used hierarchical, spatially explicit models to examine the effects of treatment timing on rodent density from pre-treatment through post-emergence. The control, two-weeks, and four-weeks treatment timings resulted in 81%, 125%, and 189% average increases in rodent densities post-treatment. The number of unique individuals of each detected species also increased post-treatment for all three treatment timings. Thus, varying chemical treatment timing for reducing/removing cover crops prior to soybean planting may be an ineffective non-lethal approach for rodent population management in agroecosystems. Nonetheless, our study provides an illustrative example of an effective, multi-site methodlogy that could be used to reliably evaluate the status of rodent populations and the potential effectiveness of other rodent management methods.
Nutrient resorption from senescing leaves can significantly affect ecosystem nutrient cycling, making it an essential process to better understand long-term plant productivity under environmental change that affects the balance between nutrient availability and demand. Although it is known that nutrient resorption rates vary strongly between different species and across environmental gradients, the underlying driving factors are insufficiently quantified. Here, we present an analysis of globally distributed observations of leaf nutrient resorption to investigate the factors driving resorption efficiencies for nitrogen (NRE) and phosphorus (PRE). Our results show that leaf structure and habit, together with indicators of nutrient availability, are the two most important factors driving spatial variation in NRE. Overall, we found higher NRE in deciduous plants (65.2 % ± 12.4 % , n=400) than in evergreen plants (57.9 % ± 11.4 %, n=551) , likely associated with a higher share of metabolic N in leaves of deciduous plants. Tropical regions show the lowest resorption for N (NRE: 52.4 % ± 12.1 % ) and tundra ecosystems in polar regions show the highest (NRE: 69.6 % ± 12.8 %), while the minimum PRE is in temperate regions (57.8 % ± 13.6 %) increasing to boreal regions (67.3 % ± 13.6 %). Soil clay content, N and P atmospheric deposition – a globally available proxy for soil fertility – and MAP played an important role in this pattern, where we found higher NRE and PRE in high latitudes. The statistical relationships developed in this analysis indicate an important role of leaf habit and type for nutrient cycling and guide improved representations of plant-internal nutrient re-cycling and nutrient conservation strategies in vegetation models.
In 2015-2019, young bluethroats were caught in order to determine the parameters of their migration stop in the taiga zone in the east of the Russian Plain. A total of 272 birds were analyzed, of which 186 were males and 86 were females. The average duration of the migration stop for young bluethroats was 1.45 days. Transient individuals have fat reserves that allow them to make migratory jumps lasting an average of 4.39 ± 0.20 h. Bluethroats with an average stopping time have a mass deposition rate of 0.04 ± 0.36 g per day and, by the time of departure, are able to make nonstop flights lasting an average of 3.89 ± 0.58 h. Individuals that make the decision to stop lose a little of their fat reserves, reducing their ability to fly nonstop until the next stop. The significance of the river valleys in the east of the Russian Plain for a successful stopover remains an open question, and it has not been fully clarified whether these places have the necessary ecological conditions for the successful stopover of small birds.
Seabirds, considered key indicators of the oceanic environment, are avian species that are highly threatened by human activities. Because many colonial breeding seabirds rely on a single breeding site for their lifetime, understanding the population dynamics and philopatry of these breeding populations is vital for conservation efforts. This study tracked 102 adult Black-tailed Gulls (Larus crassirostris) in Korea using Global Positioning System (GPS) telemetry devices for two years to ascertain survival and breeding site return rates. Using the tracking data, a known-fate survival model estimated an annual survival rate of approximately 78.85% for females and 88.90% for males. Both sexes exhibited relatively low survival rates during the migration season, potentially linked to energy expenditure during migration and differing survival capacities. The breeding site return rate was evaluated by observing the returns to breeding sites over three breeding seasons spanning from 2021 to 2023. Among the surviving individuals successfully tracked across the consecutive years, 100% returned to their original breeding sites in the second year, and 94.29% returned in the third year. This study employed robust and statistically testable methods, contributing essential information for conservation efforts. Given the limited understanding of survival and philopatry among seabird breeding populations in Korea, this study provides crucial insights into the population dynamics of Black-tailed Gulls, a representative seabird species in Korean seas.
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