A test of the substitution–habitat hypothesis in amphibians

Abstract

Most examples that support the substitution-habitat hypothesis (human-made habitats act as substitutes of original habitat) deal with birds and mammals. We tested this hypothesis in 14 amphibians by using percentage occupancy as a proxy of habitat quality (i.e., higher occupancy percentages indicate higher quality). We classified water body types as original habitat (no or little human influence) depending on anatomical, behavioral, or physiological adaptations of each amphibian species. Ten species had relatively high probabilities (0.16-0.28) of occurrence in original habitat, moderate probability of occurrence in substitution habitats (0.11-0.14), and low probability of occurrence in refuge habitats (0.05-0.08). Thus, the substitution-habitat hypothesis only partially applies to amphibians because the low occupancy of refuges could be due to the negligible human persecution of this group (indicating good conservation status). However, low occupancy of refuges could also be due to low tolerance of refuge conditions, which could have led to selective extinction or colonization problems due to poor dispersal capabilities. That original habitats had the highest probabilities of occupancy suggests amphibians have a good conservation status in the region. They also appeared highly adaptable to anthropogenic substitution habitats.

Ecological consequences of human depopulation of rural areas on wildlife: A unifying perspective

“…Amphibians and reptiles with low vagility are particularly influenced by the abandonment of farming and livestock growing (Cushman, 2006). In northern Spain, scrubland expansion in abandoned croplands negatively affects various reptile species, such as the Iberian green lizard (Lacerta schreiberi) and Seoane's viper (Vipera seoanei), as well as some amphibians such as the goldenstriped salamander (Chioglossa lusitanica) and common frogs (Rana temporaria) (Galán, 1999;Martínez-Abraín and Galán, 2017). Amphibians are also negatively affected by the widespread reliance of many populations on the existence of ponds for reproduction in agricultural areas, many of which disappear when traditional agricultural and livestock practices are discontinued (Curado et al, 2011).…”

Repensando la conservación

“…Roughly speaking, we have reached the conclusion that we can classify species into three large groups, depending on the extent of human influence over their habitat choice. A species might be found in its original habitat (equivalent to the habitat where they evolved), in a refuge (in suboptimal natural environments), or in substitution habitats -i.e., in environments created by humans which end up replacing the original habitats (Martínez-Abraín & Galán, 2018;Martínez-Abraín & Jiménez, 2016). Seagulls who breed in salt pans are an example of the latter, as are herons feeding on rice fields or urban birds that find the replacement for a cliff in a house front or a viaduct.…”

Genetic diversity, gene flow, and landscape resistance in a pond‐breeding amphibian in agricultural and natural forested landscapes in Norway

“…For some species, such large‐scale ecological factors may co‐vary positively with human impact. For example, there are several pond‐breeding amphibian species that seemingly thrive in agricultural landscapes, where they often utilize artificial ponds for reproduction (Martínez‐Abraín & Galán, 2018 ; Valdez et al., 2021 ). These agricultural areas are suitable for crop production due to rich soils and suitable climatic conditions.…”

“…In otherwise colder parts of the world, a warmer climate may also be important for both crop production and the development of amphibians from egg to metamorphosis (Newman, 1998 ). Species that have found substitutional habitats within agricultural areas are also often still present within their original, natural habitats, such as forests (Martínez‐Abraín & Galán, 2018 ). In managed forests, the level of human impact is often related to the level of site productivity (Beach et al., 2005 ), leaving areas with nutrient‐poor or climatically harsher conditions less or unimpacted by forestry activities (Farrelly et al., 2011 ).…”