A model of road effect using line integrals and a test of the performance of two new road indices using the distribution of small mammals in an Atlantic Forest landscape

Autor(es)

Freitas, Simone R. ^[1] ; Alexandrino, Marcos M. ^[2] ; Pardini, Renata ^[3] ; Metzger, Jean Paul ^[4]

Afiliação do(s) autor(es)

^[1] Univ Fed ABC, BR-09210170 Santo Andre, SP - Brazil

^[2] Univ Sao Paulo, Dept Math, Inst Math & Stat, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Dept Zool, Inst Biosci, Sao Paulo - Brazil

^[4] Univ Sao Paulo, Dept Ecol, Inst Biosci, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: ECOLOGICAL MODELLING; v. 247, p. 64-70, 2012.
• Citações Web of Science: 7

Resumo

Effects of roads on wildlife and its habitat have been measured using metrics, such as the nearest road distance, road density, and effective mesh size. In this work we introduce two new indices: (1) Integral Road Effect (IRE), which measured the sum effects of points in a road at a fixed point in the forest; and (2) Average Value of the Infinitesimal Road Effect (AVIRE), which measured the average of the effects of roads at this point. IRE is formally defined as the line integral of a special function (the infinitesimal road effect) along the curves that model the roads, whereas AVIRE is the quotient of IRE by the length of the roads. Combining tools of ArcGIS software with a numerical algorithm, we calculated these and other road and habitat cover indices in a sample of points in a human-modified landscape in the Brazilian Atlantic Forest, where data on the abundance of two groups of small mammals (forest specialists and habitat generalists) were collected in the field. We then compared through the Akaike Information Criterion (AIC) a set of candidate regression models to explain the variation in small mammal abundance, including models with our two new road indices (AVIRE and IRE) or models with other road effect indices (nearest road distance, mesh size, and road density), and reference models (containing only habitat indices, or only the intercept without the effect of any variable). Compared to other road effect indices, AVIRE showed the best performance to explain abundance of forest specialist species, whereas the nearest road distance obtained the best performance to generalist species. AVIRE and habitat together were included in the best model for both small mammal groups, that is, higher abundance of specialist and generalist small mammals occurred where there is lower average road effect (less AVIRE) and more habitat. Moreover, AVIRE was not significantly correlated with habitat cover of specialists and generalists differing from the other road effect indices, except mesh size, which allows for separating the effect of roads from the effect of habitat on small mammal communities. We suggest that the proposed indices and GIS procedures could also be useful to describe other spatial ecological phenomena, such as edge effect in habitat fragments. (C) 2012 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 00/01587-5 - Relações entre o padrão do relevo e a diversidade de espécies arbóreas em fragmentos de Mata Atlântica na região de Caucaia, SP
• Beneficiário: William Goulart da Silva
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 99/05123-4 - Conservação da biodiversidade em paisagens fragmentadas no Planalto Atlântico de São Paulo (Brasil)
• Beneficiário: Jean Paul Walter Metzger
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático
• Processo FAPESP: 06/02673-9 - Relações entre as estradas e a fragmentação florestal na região do planalto de Ibiúna (SP)
• Beneficiário: Simone Rodrigues de Freitas
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado