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(A) Estimated metapopulation carrying capacities of adult individuals for all management scenarios. Estimations were based on habitat suitability and population density. (B) Metapopulation dynamics-based estimations of minimum expected adults’ abundances for all scenarios.
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When data are limited it is difficult for conservation managers to assess alternative management scenarios and make decisions. The natterjack toad (Bufo calamita) is declining at the edges of its distribution range in Europe and little is known about its current distribution and abundance in Poland. Although different landscape management plans for...
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... W badaniu wykorzystane zostały cztery sformułowane wcześniej alternatywne scenariusze zagospodarowania doliny Wisły (regulacja rzeki, ochrona i odtworzenie użytków zielonych, zalesienie i renaturalizacja rzeki) opisujące potencjalne zagrożenia i strategie ochrony doliny Wisły w centralnej Polsce (szczegóły -patrz Romanowski, 2007;Van der Sluis et al., 2007;Franz et al., 2013). ...
... Dostępnych jest za to wiele danych demograficznych z innych lokalizacji w obrębie jej występowania w Europie. Zebrane informacje na temat ropuchy paskówki i sposób ich wykorzystania do oszacowania parametrów modelu zostały dokładnie opisane we Franz et al. (2013) oraz w materiałach on-line 1 . Ropucha paskówka w tej pracy służy jako przykład sytuacji relatywnie małej dostępności informacji na temat gatunku poddawanego analizie PVA, a zgodność użytych parametrów opisujących gatunek ze stanem rzeczywistym w tym konkretnym przypadku nie jest istotna dla porównania oprogramowania. ...
... Wybrano programy reprezentujące różne podejścia do analizy żywotności populacji: model siedliskowy (LARCH; Chardon et al., 2000), model dynamiki lokalnych populacji VORTEX (Lacy, 1993) i model metapopulacyjny META-X do porównania z wynikami modeli stworzonych w RAMAS GIS (Akçakaya, 2005). Stworzone przez Franz et al. (2013) przy użyciu RAMAS GIS modele to model siedliskowy, dalej nazywany RAMASh (habitat), oraz model metapopulacji ropuchy paskówki, dalej nazywany RAMASp (population). Modele te posłużyły w dalszej części badań jako "wirtualna" metapopulacja (sensu Zurell et al., 2009). ...
Because of the scale and speed of species extinctions conservationists require methods that facilitate decision making. Therefore, a wide range of habitat and population viability analysis (PVA) software has been developed. Given the diversity of available programs it is currently challenging to decide which program is the most appropriate for a particular problem and what has to be considered when interpreting and comparing results from different approaches. Previous comparisons of PVA software addressed more generic questions such as data requirements, assumptions and predictive accuracy. In contract, we focus on a more applied problem that is still unresolved: how do simple habitat models and PVA software packages affect the ranking of alternative management scenarios? We addressed this problem by comparing different packages (LARCH, META-X, VORTEX and RAMAS GIS). As a test case, we studied the impact of alternative landscape development scenarios (river regulation, grassland restoration, reforestation and renaturalisation) for the Vistula valley, Poland, on the natterjack toad (Bufo calamita). In this context we also aimed to assess whether the use of at least two different PVA packages can enable users to better understand the differences in model predictions, which would imply a greater awareness and critical use of the packages. Our model selection represents different approaches to population viability analysis, including habitat, local population and stochastic patch occupancy models. The models can be evaluated in regard to the complexity of parameters and to the way the landscape is handled. We used RAMAS GIS to create a habitat model (RAMASh) and a detailed spatially explicit stochastic metapopulation model (RAMASp) which combined served as a complete “virtual” dataset for parameterisation of other programs. As an example of a stochastic patch occupancy model, we selected the META-X software. For a more independent comparison we added VORTEX – another package that includes explicit population dynamics, similar to RAMAS. Additionally, we included the habitat model LARCH because this type of model is often used by policy makers. We compared the metapopulation structure produced by RAMASh and LARCH. Scenario ranking according to the predicted carrying capacity in both programs was exactly the same, because the quantitative results for each scenario were almost identical in both programs. However, the metapopulation structure showed big differences between the programs, especially in the number of small populations. The analyses of results of different PVA programs (RAMASp, VORTEX and META-X) showed that absolute values of viability measures partly differed among these programs. Slight differences in population growth rate in RAMASp and VORTEX were amplified by stochasticity and resulted in visibly lower values of final abundance in VORTEX than in RAMASp. Also the absolute values of intrinsic mean time to extinction showed some discrepancies in VORTEX and META-X. These results are in agreement with findings of previous PVA comparisons, which emphasizes that absolute values of viability measures produced by any single model should be treated with caution. Nevertheless, despite these differences the rankings of the scenarios were the same in all three programs. However the order of the scenarios was different than in habitat models. In addition, these rankings were robust to the choice of viability measure. Taken together, these results emphasize that scenario ranking delivered by PVA software is robust and thus very useful for conservation management. Furthermore, we recommend using at least two PVA software packages in parallel, as this forces user to scrutinize the simplifying assumptions of the underlying models and of the viability metrics used.
... Our goal was to predict the impact of climate change on a range edge population regionally Red-Listed as Endangered to inform species conservation management. Franz et al., 2013), is scarce. Nevertheless, Poland was included in the species IUCN range ( Figure 1). ...
The global amphibian crisis is driven by a range of stressors including disease, habitat loss, and environmental contamination. The role of climate change remains poorly studied and is likely to influence environmental suitability, ranges, reproduction, and phenology. This study aimed to characterize the bioclimatic-habitat niche space of the Natterjack toad (Epidalea calamita) throughout its European range and to assess the impact of climate on the toad's environmental suitability and breeding behavior in Ireland, where declines in recent decades have resulted in it being regionally Red-Listed as Endangered. To address these questions, we first identified which climate variables best predict the current bioclimatic niche, fecundity (number of eggs deposit), and phenology. We then used future climate projections for two time periods (2041-2060 and 2061-2080) and two greenhouse gas emission scenarios (RCP 4.5 and RCP 8.5) to predict how the species range, fecundity, and phenology would change. The European range of the species was found to be limited by winter temperatures while its bioclimatic niche varied markedly throughout its range. Species distribution models suggested projected climate change will increase environmental suitability for the species throughout its range, including Ireland, but most notably in Scandinavia and the Baltic. Fecundity in Ireland was greatest during the cool temperatures of spring and after wet winters associated with ephemeral breeding pool availability. Warm, dry summers in the preceding year influenced fecundity the following spring indicative of carryover effects. Initiation of spawning was driven by spring temperatures, not rainfall. Projections suggested future climate change may increase fecundity in Ireland while spawning may commence earlier throughout the 21st century especially under a high greenhouse gas emission scenario (RCP 8.5). Despite recent range contraction and population declines due to habitat deterioration , the Natterjack toad, if subject to a suitable species conservation strategy, has the potential to be a climate change winner, notwithstanding unpredictable habitat and land-use change, sea-level rise inducing coastal erosion, changes in invertebrate prey abundance, and disease.
... The parameters were calibrated for species and ecosystems in the Netherlands (Foppen et al., 1999;Verboom et al., 2001;Verboom & Pouwels, 2004). The LARCH model was applied in many different countries and regions where case parameters were adjusted according to the local conditions, for example in North-West Europe, Poland, the Meuse Basin, the river Rhine, Abruzzo, Umbria and Emilia Romagna regions in Italy, Catalunya in Spain, Israel and Ukraine (Franz et al., 2013;Franz et al., 2011;Geilen et al., 2001;Groot Bruinderink et al., 2003;Pungetti & Van der Sluis, 2002;Van der Sluis et al., 2007;Van der Sluis & Van Eupen, 2013). ...
... These include Frank and Wissel's (2002) approximation for the mean time to extinction, which approximates a stochastic patch occupancy model and metapopulation capacity, a deterministic measure of metapopulation persistence (Hanski & Ovaskainen 2000). More complex still are metapopulation models that attempt to account for population processes including variation in individual mortality and fecundity, dispersal, and environmental and demographic stochasticity (Akcakaya et al. 2004;Wintle et al. 2005a;Franz et al. 2013). ...
Approaches to assess the impacts of landscape disturbance scenarios on species range from metrics based on patterns of occurrence or habitat to comprehensive models that explicitly include ecological processes. The choice of metrics and models affects how impacts are interpreted and conservation decisions. We explored the impacts of 3 realistic disturbance scenarios on 4 species with different ecological and taxonomic traits. We used progressively more complex models and metrics to evaluate relative impact and rank of scenarios on the species. Models ranged from species distribution models that relied on implicit assumptions about environmental factors and species presence to highly parameterized spatially explicit population models that explicitly included ecological processes and stochasticity. Metrics performed consistently in ranking different scenarios in order of severity primarily when variation in impact was driven by habitat amount. However, they differed in rank for cases where dispersal dynamics were critical in influencing metapopulation persistence. Impacts of scenarios on species with low dispersal ability were better characterized using models that explicitly captured these processes. Metapopulation capacity provided rank orders that most consistently correlated with those from highly parameterized and data‐rich models and incorporated information about dispersal with little additional computational and data cost. Our results highlight the importance of explicitly considering species’ ecology, spatial configuration of habitat, and disturbance when choosing indicators of species persistence. We suggest using hybrid approaches that are a mixture of simple and complex models to improve multispecies assessments.
... Collisions with automobiles are particularly acute during the spring breeding season (Orłowski et al. 2008) but may also be high during autumnal migrations (Gryz and Krauze 2008;Wojdan 2010). Mortality of adults on roads was identified as a key parameter governing the metapopulation dynamics of natterjack toads and their long-term conservation in central Poland (Franz et al. 2013). Amphibians' mortality on roads has been well-documented in suburban areas (Najbar et al. 2006;Hetmański et al. 2007;Elzanowski et al. 2009;Błażuk 2010), agricultural landscapes (Orłowski 2007), and in relatively natural areas such as national parks or other forms of protected landscape (Figure 56.1) (Wołk 1978;Rybacki 1995;Zamachowski and Plewa 1996;Bartoszewicz 1997;Baldy 2002;Rybacki and Krupa 2002;Rybacki and Domańska 2004;Gryz and Krauze 2008;Ogielska et al. 2008;Elzanowski et al. 2009;Wojdan 2010;Brzeziński et al. 2012;Arciszewski 2015). ...
... The species is uncommon throughout most of its range, and, while it has been the subject of considerable conservation efforts in North-west Europe (Banks, Beebee, and Cooke 1994;Becart, Aubry, and Emmerson 2007), information from most of the eastern part of its range is extremely sparse (e.g. Franze et al. 2013). The population groups in Latvia are essential for long-term persistence of this species in the East Baltic Region, since it connects with the endangered northernmost E. calamita population from the coastal areas and islands of Western Estonia, which has lost two thirds of its previously documented localities between the 1930s and 2000s (Rannap, Lohmus, and Jakobson 2007), and a less studied population in Lithuania which is considered to inhabit the whole territory of that State (Gruodis, Caune, and Vilnītis 1986;Rašomavičius 2007). ...
Historical data indicate the presence of two Epidalea calamita population groups in Latvia in the past, one in western Latvia and another connecting populations from Estonia and Lithuania – in central Latvia. Both groups have experienced local extinctions that started after the Second World War in the coastal habitats around developing cities, where there were possible bottlenecks limiting population connectivity. Presently E. calamita’s range in Latvia has become split into four small- to medium-sized population groups with only two of them having connections with populations in neighbouring states, and this has produced major range gaps in Latvia dividing the once variably connected East Baltic E. calamita populations. The process of E. calamita range shrinkage continues, and we suggest that the main risk for population sustainability in the region is a combination of adverse local factors or occasional climate events with poor population connectivity and dispersal barriers.
... Compared to some other toads in which mass mortality is prevalent (Franz et al. 2013;Santos et al. 2007), we witnessed only two females who seem to have died in association with breeding activities; both these bore the swimming scar made by the male during amplexed swimming. However, it is possible that some may have died and been washed away by the current. ...
Endemic to Sri Lanka, genus Adenomus contains two torrent-associated toad species whose ecology and natural history in the wild is virtually unknown. Adenomus kelaartii is relatively common, with a wide geographic distribution. Its sister species, A. kandianus, however, is restricted to two isolated populations in fast-disappearing montane and sub-montane forests. Formally declared extinct after not being recorded for over a century, following several years of surveying, a few A. kandianus were found in 2012 and referred to as "the world's rarest toad." However, tadpoles of A. kandianus bearing unique ventral suckers were soon discovered, but the rarity of the adult and the profusion of tadpoles were never explained. Here, using ecological methods, niche modeling and DNA-barcoding, we aim to understand the ecology, natural history and distribution of this rare toad. Following a two-year study of occurrence, habits and habitat associations of adults and larvae, we show this to be a secretive species with a patchy distribution. During non-mating periods female toads (N = 23) were found in primary forests habitat up to 650 m away from the breeding streams, and predominantly males in the riparian zone (12 males, 2 females). Following heavy rain they form large (N = 388) but patchy mating congregations in torrential streams (six sites; range 0−95 mating pairs; mean = 25, SD = 38.16, CV = 152%). Amplexed pairs swim synchronously, enabling them to traverse fast currents. Egg-laying sites remain unknown, but ability to dive, vocalize underwater, and characteristics of the eggs, suggests that they lay eggs in dark recesses of the stream. Quadrat sampling of tadpoles show microhabitat partitioning (in depth, flow-rate and substrate conditions) within the stream: the greatest diversity of larval developmental stages (25-42) in slow-flowing (depth, 0.75−1.5 m) rocky areas; more robust stages (31−39) bearing sucker discs utilize rocky-rapids (depth, 0.25−0.75 m); metamorphic stages (43-45) use stream margins (depth, <0.25 m); slow flowing silt covered areas of the stream were unoccupied, irrespective of the depth. DNA barcoding of the 16S rRNA gene fragment from the two known localities confirms the identity of the Pedro population also as A. kandianus. The uncorrected pairwise genetic distance of 0.1−0.7% suggests historical gene flow between the two populations. Distribution modeling (using MaxEnt), with forest-cover layers added, predicts a very small remaining area of suitable habitats (an area of occupancy of 16 km2 and an extent of occurrence of 128 km2) isolated by habitats that are not conducive to these toads. While the healthy population recorded at one site gives hope for the survival of the species, long-term conservation of this climatically and ecologically restricted species hinges largely on the preservation of cloud and riparian forests and the unpolluted high-flow torrents.
... Compared to some other toads in which mass mortality is prevalent (Franz et al. 2013;Santos et al. 2007), we witnessed only two females who seem to have died in association with breeding activities; both these bore the swimming scar made by the male during amplexed swimming. However, it is possible that some may have died and been washed away by the current. ...
Endemic to Sri Lanka, genus Adenomus contains two torrent-associated toad species whose ecology and natural history in the wild is virtually unknown. Adenomus kelaartii is relatively common, with a wide geographic distribution. Its sister species, A. kandianus , however, is restricted to two isolated populations in fast-disappearing montane and sub-montane forests. Formally declared extinct after not being recorded for over a century, following several years of surveying, a few A. kandianus were found in 2012 and referred to as "the world's rarest toad." However, tadpoles of A. kandianus bearing unique ventral suckers were soon discovered, but the rarity of the adult and the profusion of tadpoles were never explained. Here, using ecological methods, niche modeling and DNA-barcoding, we aim to understand the ecology, natural history and distribution of this rare toad. Following a two-year study of occurrence, habits and habitat associations of adults and larvae, we show this to be a secretive species with a patchy distribution. During non-mating periods female toads ( N = 23) were found in primary forests habitat up to 650 m away from the breeding streams, and predominantly males in the riparian zone (12 males, 2 females). Following heavy rain they form large ( N = 388) but patchy mating congregations in torrential streams (six sites; range 0−95 mating pairs; mean = 25, SD = 38.16, CV = 152%). Amplexed pairs swim synchronously, enabling them to traverse fast currents. Egg-laying sites remain unknown, but ability to dive, vocalize underwater, and characteristics of the eggs, suggests that they lay eggs in dark recesses of the stream. Quadrat sampling of tadpoles show microhabitat partitioning (in depth, flow-rate and substrate conditions) within the stream: the greatest diversity of larval developmental stages (25-42) in slow-flowing (depth, 0.75−1.5 m) rocky areas; more robust stages (31−39) bearing sucker discs utilise rocky-rapids (depth, 0.25−0.75 m); metamorphic stages (43-45) use stream margins (depth, <0.25 m); slow flowing silt covered areas of the stream were unoccupied, irrespective of the depth. DNA barcoding of the 16S rRNA gene fragment from the two known localities confirms the identity of the Pedro population also as A. kandianus . The uncorrected pairwise genetic distance of 0.1−0.7% suggests historical gene flow between the two populations. Distribution modeling (using MaxEnt), with forest-cover layers added, predicts a very small remaining area of suitable habitats (an area of occupancy of 16 km ² and an extent of occurrence of 128 km ² ) isolated by habitats that are not conducive to these toads. While the healthy population recorded at one site gives hope for the survival of the species, long-term conservation of this climatically and ecologically restricted species hinges largely on the preservation of cloud and riparian forests and the unpolluted high-flow torrents.
... Goede jaren met hoge N b kunnen de slechte jaren met lage N b bufferen (Schmeller & Merilä, 2007 (Stevens et al., 2006b). Hoewel wegen tot de verkozen landschapsoppervlaktes behoren voor dispersie, kan toenemende mortaliteit langs deze verkeersassen een rem betekenen voor migratie (Beebee, 2013;Franz et al., 2013;Frei, 2014;Garriga et al., 2012). Er is een duidelijke positieve relatie tussen de effectieve populatiegrootte en de genetische variatie van subpopulaties. ...
... An important question to consider, therefore, is how much complexity is needed in order to address a conservation question (see Box 2). Once carefully designed and applied, it is then important to ensure valid interpretation, e.g., by ranking alternative solutions ( Franz et al. 2013). ...
