title: Road networks predict human influence on Amazonian bird communities.
abstract: Road building can lead to significant deleterious impacts on biodiversity, varying from direct road-kill mortality and direct habitat loss associated with road construction, to more subtle indirect impacts from edge effects and fragmentation. However, little work has been done to evaluate the specific effects of road networks and biodiversity loss beyond the more generalized effects of habitat loss. Here, we compared forest bird species richness and composition in the municipalities of Santarém and Belterra in Pará state, eastern Brazilian Amazon, with a road network metric called 'roadless volume (RV)' at the scale of small hydrological catchments (averaging 3721 ha). We found a significant positive relationship between RV and both forest bird richness and the average number of unique species (species represented by a single record) recorded at each site. Forest bird community composition was also significantly affected by RV. Moreover, there was no significant correlation between RV and forest cover, suggesting that road networks may impact biodiversity independently of changes in forest cover. However, variance partitioning analysis indicated that RV has partially independent and therefore additive effects, suggesting that RV and forest cover are best used in a complementary manner to investigate changes in biodiversity. Road impacts on avian species richness and composition independent of habitat loss may result from road-dependent habitat disturbance and fragmentation effects that are not captured by total percentage habitat cover, such as selective logging, fire, hunting, traffic disturbance, edge effects and road-induced fragmentation.
authors.affiliation: Computational Science Laboratory, Microsoft Research, 21 Station Road, Cambridge CB1 2FB, UK Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK sadia@microsoft.com.
authors.forename: Sadia E
authors.initials: SE
authors.lastname: Ahmed
authors.affiliation: Coordenação de Zoologia Museu Paraense Emílio Goeldi, CP 399, Avenida Perimetral, 1901, Terra Firme, Belém, Pará 66077-530, Brazil.
authors.forename: Alexander C
authors.initials: AC
authors.lastname: Lees
authors.affiliation: Curso de Pós-Graduação de Zoologia, Universidade Federal do Pará/Museu Paraense Emílio Goeldi, Caixa Postal 399, Belém, Pará 66040-170, Brazil.
authors.forename: Nárgila G
authors.initials: NG
authors.lastname: Moura
authors.affiliation: Stockholm Environment Institute, 87D Linegatan, Stockholm, Sweden International Institute for Sustainability, Estrada Dona Castorina 124, Rio de Janeiro 22460-320, Brazil.
authors.forename: Toby A
authors.initials: TA
authors.lastname: Gardner
authors.affiliation: Coordenação de Zoologia Museu Paraense Emílio Goeldi, CP 399, Avenida Perimetral, 1901, Terra Firme, Belém, Pará 66077-530, Brazil Lancaster Environment Centre, Lancaster University, Lancaster LA1 3HE, UK.
authors.forename: Jos
authors.initials: J
authors.lastname: Barlow
authors.affiliation: Embrapa Amazônia Oriental, Travessa Dr. Enéas Pinheiro s/n, Caixa Postal 48, Belém, Pará 66095-100, Brazil.
authors.forename: Joice
authors.initials: J
authors.lastname: Ferreira
authors.affiliation: Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Ewers
mesh_terms: D000818:Animals; D044822:Biodiversity; D001717:Birds / Q000502:physiology*; D001938:Brazil; D003247:Conservation of Natural Resources / Q000379:methods*; D017753:Ecosystem; D014186:Transportation
keywords: Amazon; biodiversity; forest birds; infrastructure development; road density; road effects