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Dynamic and diverse amphibian assemblages: Can we differentiate natural processes from human induced changes?
Nathália G S Lima1, Ubirajara Oliveira2, Rafael C C Souza3
1Programa de Pós-Graduação em Ecologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil.
Plos One
|March 27, 2019
Summary
Amphibian populations in Brazil are hard to track due to low detectability, making it difficult to distinguish natural fluctuations from declines caused by habitat changes. Further research is needed to improve amphibian monitoring techniques.
Area of Science:
- Ecology
- Herpetology
- Conservation Biology
Background:
- Amphibians are sensitive indicators of environmental change, affected by both natural and human-driven habitat alterations.
- Accurate field inventories are challenging due to the inherent difficulty in detecting amphibians, especially in diverse tropical ecosystems.
- Understanding drivers of amphibian assemblage dynamics requires a multiscale approach, considering microhabitat to landscape factors and imperfect detection.
Purpose of the Study:
- To investigate the effects of natural and anthropogenic habitat changes on anuran assemblages over a 16-year period.
- To differentiate the impacts of natural environmental drivers from landscape-level anthropogenic changes on amphibian species composition.
- To assess the influence of microhabitat, riparian vegetation, and land cover on anuran diversity and occupancy, while accounting for imperfect detection.
Main Methods:
- Conducted field inventories of tadpoles and adult frogs in 16 streams over two time periods 16 years apart.
- Quantified microhabitat availability, riparian vegetation changes, and land cover alterations within stream buffers.
- Analyzed species richness, diversity, nestedness, and turnover, incorporating models for imperfect detection and human occupancy.
Main Results:
- Microhabitat and riparian vegetation alterations partially explained changes in anuran species composition and detection between sampling periods.
- Landscape stability appeared to influence the nestedness component of species diversity.
- Low detectability limited robust occupancy estimates for most species, hindering direct association of observed occupancy changes with anthropogenic causes.
Conclusions:
- Natural changes in local habitats significantly influence anuran distribution in montane meadows.
- Observed changes in occupancy for some species over 16 years could not be directly attributed to anthropogenic factors.
- The low detectability of many amphibian species poses a significant challenge for monitoring population declines and distinguishing them from natural fluctuations, highlighting the need for improved detection techniques.
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