title: Testing the relationship between human occupancy in the landscape and tadpole developmental stress.
abstract: Amphibian population declines are widespread; the main causal factors are human related and include habitat fragmentation due to agriculture, mining, fires, and urban development. Brazil is the richest country in species of amphibians, and the Brazilian regions with the greatest amphibian diversity are experiencing relatively high rates of habitat destruction, but there are presently relatively few reports of amphibian declines. It is thus important to develop research methods that will detect deterioration in population health before severe declines occur. We tested the use of measurements of fluctuating asymmetry (FA) taken on amphibian larvae to detect anthropogenic stress. We hypothesized that greater human occupancy in the landscape might result in more stressful conditions for amphibians. We conducted this study at the Espinhaço mountain range in southeastern Brazil, using as a model an endemic species (Bokermannohyla saxicola, Hylidae). We chose two tadpole denticle rows and eye-nostril distance as traits for FA measurement. We measured percent cover of human-altered habitats in the landscape around tadpole sampling points and measured FA levels in sampled tadpoles. We found FA levels to differ among localities but found no relationship between human modification of the landscape and tadpole FA levels. Levels of FA in the traits we examined may not be strongly affected by environmental conditions, or may be affected by local variables that were not captured by our landscape-scale measures. Alternatively, populations may be genetically differentiated, affecting how FA levels respond to stress and obscuring the effects of anthropogenic disturbance.
authors: Programa de Pós Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors: Paula C
authors: PC
authors: Eterovick
authors: Programa de Pós Graduação em Zoologia de Vertebrados, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors: Luís F F
authors: LF
authors: Bar
authors: Programa de Pós Graduação em Geografia-Tratamento da Informação Espacial, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors: Jorge B
authors: JB
authors: Souza
authors: Programa de Pós Graduação em Geografia-Tratamento da Informação Espacial, Pontifícia Universidade Católica de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors: José F M
authors: JF
authors: Castro
authors: Instituto de Ciências Biológicas e da Saúde, Universidade Federal de Viçosa, Campus Florestal, Florestal, Minas Gerais, Brazil.
authors: Felipe S F
authors: FS
authors: Leite
authors: College of Marine and Environmental Science, Centre for Tropical Biodiversity and Climate Change, James Cook University, Townsville, Queensland, Australia.
authors: Ross A
authors: RA
authors: Alford
mesh_terms: D000663:Amphibians / Q000254:growth & development / Q000502:physiology*; D000818:Animals; D017753:Ecosystem; D056727:Endangered Species; D006801:Humans; D007814:Larva / Q000254:growth & development; D011156:Population Density; D013312:Stress, Physiological