Metapopulation Dynamics of Endangered Amphibians in Fragmented Wetland Networks
DOI::
https://doi.org/10.70102/AEJ.2025.17.2.45کلمات کلیدی:
Metapopulation dynamics, Habitat fragmentation, Amphibian conservation, Wetland connectivity, Patch occupancy, Colonization–Extinction Dynamics, Landscape ecology.چکیده
Habitat fragmentation is one of the major threats to global amphibian extinctions, particularly for low-dispersal wetland-dependent species. The research questions this study seeks to answer is the metapopulation dynamics of threatened amphibians in a fragmented wetland landscape, and to assess the effects of patch isolation, size, and patch connectivity on patch occupancy, colonization, and extinction. The surveys were conducted across 48 wetlands over 5 years (2019-2024), with mark-recapture and environmental DNA (eDNA) sampling used to estimate population parameters. Using a spatially explicit metapopulation model, a mean patch occupancy of 0.62 ± 0.08 (SE) across the study period was found, with annual colonization and extinction probabilities of 0.27 and 0.19, respectively. The wetland size was strongly positively correlated with occupancy (β = 0.41, p < 0.001), and the isolation distance negatively affected colonization rates (β = -0.36, p = 0.004). The occupancy patterns (R2) were explained by connectivity indices (R2 = 0.58). It is important to note that wetlands within 500m of neighboring patches had a 34% greater chance of persistence than those in more isolated regions. Simulation results suggested that a 20% improvement in linkage would decrease the likelihood of extinction by about 15% over 10 years. On the other hand, a further loss of habitat at the current rate of destruction (about 3%/year) is expected to reduce the overall metapopulation's viability by 40% in 15 years. Such results underscore the vital role of preserving functional connectivity and of focusing on larger habitat patches in conservation planning. Endangered amphibian species require strategic restoration of wetland corridors and mitigation of fragmentation effects to improve future persistence in evolving landscapes.