Conservation implications of a limited avian cross-habitat spillover in pasture lands. (January 2021)

• Record Type: Journal Article
• Authors: Boesing, Andrea Larissa; Marques, Thiago Simon; Martinelli, Luiz Antonio; Nichols, Elizabeth; Siqueira, Paulo Ricardo; Beier, Christian; de Camargo, Plinio Barbosa; Metzger, Jean Paul
• Is Part Of: Biological conservation. Volume 253(2021)
• Publication Date: 2021-01
• Subjects: Landscape complementation -- Landscape supplementation -- Stable isotopes -- Agricultural landscapes -- Brazilian Atlantic Forest -- Birds; Conservation of natural resources -- Periodicals; Nature conservation -- Periodicals; Ecology -- Periodicals; Environment -- Periodicals; Environmental Pollution -- Periodicals; Electronic journals; 333.9516
• DOI: 10.1016/j.biocon.2020.108898
• Languages: English
• ISSNs: 0006-3207

Abstract

Abstract: Increasing evidence demonstrates a role for the cross-habitat spillover process in the maintenance of biodiversity in managed agricultural landscapes. However, the mechanisms that drive this process are less well understood. In particular, it is critical to know how landscape structure modulates spillover movements, and whether species are moving through the matrix to acquire resources or simply to disperse between habitat fragments. We tested landscape effects and food resource use within cattle pasture matrices. We used mist-nets to collect data on avian communities across 51 sampling sites, spanning a forest cover gradient. We additionally integrated stable isotopic analysis (δ 13 C signature) to determine the provenance of resources used (either forest - dominated by C3 plants; or pasture, dominated by C4 ). Bird movement across pasture matrices was extremely reduced, and bird occupation was concentrated near forest edges. There was a clear distinction of resource use according to species' habitat preferences, with forest-species foraging predominantly in-forests, open-area species in pastures, and generalist species having more varied diets, but still relying on a large proportion of C3 sources. Forest cover was unrelated to avian spillover from forests into pastures, but positively related to C3 signatures for both forest and open-area associated species. Finally, we found that most birds moving from forests to pastures were habitat generalists (63%), and that pastures work as a barrier for forest-associated species movement. Landscapes dominated by pasture are very unfavorable to the conservation of forest species, but potentially can maintain ecosystem services from the spillover of generalist species. Highlights: Pasture matrices drastically reduces avian movement in fragmented landscapes Habitat cover and isolation influences avian resource use in fragmented landscapes Habitat-generalist bird species compose the majority of movement events across pastures Habitat-generalists are effective foraging-related ecosystem service agents in high-contrasting matrices Stable isotopes in landscape-level studies may improve our understanding of ecological processes in fragmented landscapes