1
|
de Zwaan DR, Hannah KC, Alavi N, Mitchell GW, Lapen DR, Duffe J, Wilson S. Local and regional-scale effects of hedgerows on grassland- and forest-associated bird populations within agroecosystems. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2024; 34:e2959. [PMID: 38421094 DOI: 10.1002/eap.2959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/07/2023] [Accepted: 01/10/2024] [Indexed: 03/02/2024]
Abstract
Linear woody features (LWFs), like hedgerows along field edges, provide wildlife habitat and support biodiversity in agroecosystems. Assessments of LWFs usually focus on community-level indices, such as species richness. However, effective conservation actions need to balance the contrasting habitat preferences of different wildlife species, necessitating a focus on population-level effects in working landscapes. We assessed associations between LWFs and abundance for 45 bird species within an intensive agroecosystem in eastern Ontario, Canada. We used distance- and removal-sampling methods across 4 years (2016-2019) to estimate local bird abundance in habitats representing a range of LWF densities. We also predicted abundance across a subset of the study region with and without LWFs to understand their contribution to regional population density. Associations between local bird abundance and LWFs were variable among species, but overall community effects were clearly positive, particularly for forest and shrubland species. At the site level, 20/45 species (44%) had higher densities associated with greater LWF presence on average, compared to 5/45 (11%) with negative associations. At the regional scale, LWFs had predicted benefits on total abundance for 31 species (69%), contributing to an estimated 20% increase on average. Positive effects were most pronounced in areas with greater agricultural land use (primarily field crops), suggesting LWFs may provide crucial habitat in heavily modified landscapes but have little to no additional benefit for the avian community in areas with greater existing heterogeneity and habitat retention. Species that responded negatively tended to be at risk with strong habitat preferences for intact forests or large, open grasslands and, thus, greater sensitivity to potential edge effects. With rapidly declining songbird populations and a global need for food security, conservation strategies that amplify biodiversity and enhance agricultural productivity through ecosystem services such as pest control, pollination, and water regulation are vital. We demonstrate the benefits of habitat heterogeneity in agroecosystems on songbird densities and highlight the need to integrate local and landscape-level assessments in conservation planning. An effective, balanced strategy includes concentrating LWFs in areas of extensive arable crops, with habitat retention patches where possible, while maintaining heterogeneity through mixtures of natural habitats and pastoral farming in less intensive regions.
Collapse
Affiliation(s)
- Devin R de Zwaan
- Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada
- Department of Biology, Acadia University, Wolfville, Nova Scotia, Canada
| | - Kevin C Hannah
- Canadian Wildlife Service, Environment & Climate Change Canada, Ottawa, Ontario, Canada
| | - Niloofar Alavi
- Landscape Science and Technology, Environment & Climate Change Canada, Ottawa, Ontario, Canada
| | - Greg W Mitchell
- Wildlife Research Division, Environment & Climate Change Canada, Ottawa, Ontario, Canada
- Department of Biology, Carleton University, Ottawa, Ontario, Canada
| | - David R Lapen
- Agriculture and Agri-Food Canada, Science and Technology Branch, Ottawa, Ontario, Canada
| | - Jason Duffe
- Landscape Science and Technology, Environment & Climate Change Canada, Ottawa, Ontario, Canada
| | - Scott Wilson
- Department of Forest & Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Wildlife Research Division, Environment & Climate Change Canada, Delta, British Columbia, Canada
| |
Collapse
|
2
|
Rurangwa ML, Niyigaba P, Tobias JA, Whittaker RJ. Functional and phylogenetic diversity of an agricultural matrix avifauna: The role of habitat heterogeneity in Afrotropical farmland. Ecol Evol 2022; 12:e9024. [PMID: 35822114 PMCID: PMC9259849 DOI: 10.1002/ece3.9024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/12/2022] [Accepted: 05/18/2022] [Indexed: 11/08/2022] Open
Abstract
Varied strategies to alleviate the loss of farmland biodiversity have been tested, yet there is still insufficient evidence supporting their effectiveness, especially when considering phylogenetic and functional diversity alongside traditional taxonomic diversity metrics. This conservation challenge is accentuated in the Afrotropics by the rapid agricultural expansion and intensification for the production of cash crops and by a comparative lack of research. In this study, we assessed how farming practices influence avian phylogenetic and functional diversity. We conducted point-count surveys to assess avian diversity in monocultures of tea and mixed crop farming systems surrounding the Nyungwe rainforest in south-west Rwanda, allowing us to investigate the drivers of avian diversity at farm level. Species composition was found to be moderately different between farm types, with mixed crop farms supporting higher phylogenetic diversity than tea plantations. There were no significant seasonal differences in species composition, functional or phylogenetic diversity. Overall, functional diversity did not differ between farm types, but the dispersion of trophic-related traits was significantly higher in mixed crop farms. Both functional and phylogenetic diversity were influenced by floristic diversity, vegetation height, tree number, and elevation to varying degrees. Our results also (i) highlight the role of farmland heterogeneity (e.g., crop species composition, height, and tree cover extent) in encouraging avian functional and phylogenetic diversity in the Afrotropics and (ii) indicate that the generally negative biodiversity impacts of monoculture agriculture can be partially alleviated by extensive agroforestry with an emphasis on indigenous tree species.
Collapse
Affiliation(s)
| | | | - Joseph A. Tobias
- Faculty of Natural Sciences, Department of Life SciencesImperial College LondonBerksUK
| | - Robert J. Whittaker
- School of Geography and the EnvironmentUniversity of OxfordOxfordUK
- Center for Macroecology, Evolution and Climate, GLOBE InstituteUniversity of CopenhagenCopenhagenDenmark
| |
Collapse
|
3
|
Hordley LA, Gillings S, Petchey OL, Tobias JA, Oliver TH. Diversity of response and effect traits provides complementary information about avian community dynamics linked to ecological function. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Owen L. Petchey
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Joseph A. Tobias
- Department of Life Sciences Imperial College London Berkshire UK
| | | |
Collapse
|