Human activities have caused massive losses of natural populations across the globe. Like many groups, amphibians have experienced substantial declines worldwide, driven by environmental changes such as habitat conversion, pollution, and disease emergence. Each of these drivers is often found in close association with the presence of roads. Here we report a novel consequence of roads affecting an amphibian native to much of North America, the wood frog ( Interestingly, northern populations experience more intense winters, which tends to result in more de‐icing salt runoff and increased energetic demands associated with overwintering cryoprotection needs. Thus, this emerging consequence of roads appears to impose potential fitness costs associated with locomotion, and these effects might be most impactful on populations living in regions where de‐icing is most intense. Together, our findings reveal a novel set of impacts of roads and runoff pollution on wood frog physiology and performance, which seem likely to contribute to population decline. Given the global prevalence of roads and increasing salinisation of freshwater habitats, oedema and related impacts could be widespread consequences faced by amphibian populations across much of the planet's temperate zones.
Global tropical forests have been modified and fragmented by commodity agroforests, leading to significant alterations in ecological communities. Nevertheless, these production landscapes offer secondary habitats that support and sustain local biodiversity. In this study, we assess community level and species‐specific responses of amphibians to land management in areca, coffee and rubber, three of the largest commodity agroforests in the Western Ghats. A total of 106 agroforests across a 30,000‐km2landscape were surveyed for amphibians using a combination of visual and auditory encounter surveys. We used a Bayesian multi‐species occupancy modelling framework to examine patterns of species richness, beta diversity, dominance structure and individual species occupancies. The influence of biogeographic variables such as elevation and latitude as well as microhabitat availability of streams, ponds and unpaved plantation roads was tested on amphibian species occupancy. Coffee agroforests had the highest species richness and lowest dominance when compared to areca and rubber. Beta diversity was highest in areca for within agroforest measures. Compared across agroforests, coffee had highest beta diversity with areca and rubber. Both elevation and latitude showed an overall positive association with amphibian occupancy, although species‐specific responses varied considerably. Microhabitat availability was one of the strongest predictors of amphibian occupancy, with mean community response being positive with presence of water bodies and roads. Pond presence increased species richness per site by 34.7% (species‐specific responses in occupancy ranged from –2.7% to 327%). Stream presence alone did not change species richness but species‐specific response ranged from –59% to 273%. Presence of plantation roads also increased species richness by 21.5% (species‐specific response ranged from –82% to 656%). Being unpaved with little vehicular traffic, plantation roads seem to provide additional habitats for amphibians. Presence of all three microhabitats at a site increased species richness by 75%. Our study highlights the importance of land management strategies that maintain diverse native canopy and freshwater bodies and other microhabitats in sustaining amphibian fauna. Market‐driven land‐use change from coffee to other agroforest types will have detrimental effects on amphibian communities and their long‐term sustainability in the Western Ghats.
- PAR ID:
- 10448398
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Ecological Solutions and Evidence
- Volume:
- 2
- Issue:
- 4
- ISSN:
- 2688-8319
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Rana sylvatica ). Across 38 populations distributed from southern to central New England, we found that adult wood frogs living adjacent to roads had higher incidence and severity of oedema (indicated by obvious bloating caused by subcutaneous fluid accumulation) during the breeding season than frogs living away from the influence of roads. This effect was best explained by increased conductivity of breeding ponds, probably caused by runoff pollution from road salt used for de‐icing. Oedema severity was negatively correlated with locomotor performance in more northerly populations. -
Abstract Understanding the drivers of ant diversity and co‐occurrence in agroecosystems is fundamental because ants participate in interactions that influence agroecosystem processes. Multiple local and regional factors influence ant community assembly.
We examined local factors that influence the structure of a twig‐nesting ant community in a coffee system in Mexico using an experimental approach. We investigated whether twig characteristics (nest entrance size and diversity of nest entrance sizes) and nest strata (canopy shade tree or coffee shrub) affected occupation, species richness, and community composition of twig‐nesting ants and whether frequency of occupation of ant species varied with particular nest entrance sizes or strata.
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We found 33 ant species occupying 73% of nests placed. Nest colonization did not differ with nest strata or size. Mean species richness of colonizing ants was significantly higher in the diverse nest size entrance treatment, but did not differ with nest strata. Community composition differed between strata and also between the diverse and uniform size treatments on coffee shrubs, but not on shade trees. Some individual ant species were more frequently found in certain nest strata and in nests with certain entrance sizes.
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Summary Plant associated mutualists can mediate invasion success by affecting the ecological niche of nonnative plant species. Anthropogenic disturbance is also key in facilitating invasion success through changes in biotic and abiotic conditions, but the combined effect of these two factors in natural environments is understudied.
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We conclude that roadside disturbance has a positive effect on AM fungal colonisation and richness, possibly supporting the spread of nonnative plants, but that there is no absolute limitation of belowground mutualists, even at high elevation.