Document Type

Article

Publication Date

2023

DOI

10.1007/s10980-023-01668-0

Publication Title

Landscape Ecology

Volume

38

Issue

8

Pages

1955-1970

Abstract

Context Spatial occupancy and local abundance of species often positively covary, but the mechanisms driving this widespread relationship are poorly understood. Resource dynamics and habitat changes have been suggested as potential drivers, but long-term studies relating them to abundance and occupancy are rare. In this 34-year study of acorn woodpeckers (Melanerpes formicivorus), a cooperatively breeding species, we observed a paradoxical response to changes in habitat composition: despite a reduction in the availability of high-quality breeding habitat, the population increased considerably.

Objectives We investigated the role of annual variation in food availability and long-term changes in habitat composition as predictors of population dynamics.

Methods Using model selection, we contrasted competing hypotheses on the effects of changing resource availability on occupancy and social group size across three spatial scales: territory, neighborhood, and landscape.

Results The increase in abundance was largely determined by the formation of new social groups, driven by a landscape-level expansion of canopy cover and its interaction with neighborhood-level acorn abundance, indicative of long-term increases in overall acorn productivity. Group size increased with neighborhood acorn crop two years earlier but groups were smaller in territories with more canopy cover.

Conclusions Our results indicate that scale-dependent processes can result in paradoxical relationships in systems with spatial and temporal resource heterogeneity. Moreover, the findings support the role of resources in driving changes in abundance and occupancy at a landscape scale, suggesting that colonization of marginal habitat drives the positive occupancy-abundance relationship in this cooperatively breeding species.

Rights

This article is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original authors and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

© The Author(s) 2023

Data Availability

Article states: The data used in the analysis are available in Data Dryad. Citizen science data from the Audubon Christmas Bird Count can be downloaded at https://netapp.audubon.org/cbcobservation/

Original Publication Citation

Hagemeyer, N. D. G., Pesendorfer, M. B., Koenig, W. D., & Walters, E. L. (2023). Unraveling a paradox of habitat relationships: Scale-dependent drivers of temporal occupancy-abundance relationships in a cooperatively breeding bird. Landscape Ecology, 38(8),1955-1970. https://doi.org/10.1007/s10980-023-01668-0

ORCID

0000-0001-5368-4598 (Hagemeyer), 0000-0002-9414-5758 (Waters)

 
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