Divergence in sink contributions to population persistence. Issue 6 (30th May 2015)

• Record Type: Journal Article
• Authors: Heinrichs, Julie A.; Lawler, Joshua J.; Schumaker, Nathan H.; Wilsey, Chad B.; Bender, Darren J.
• Is Part Of: Conservation biology. Volume 29:Issue 6(2015)
• Page Start: 1674
• Page End: 1683
• Publication Date: 2015-05-30
• Subjects: Dipodomys ordii -- ecological traps -- population persistence -- sink contributions -- source–sink dynamics -- spatially explicit individual‐based model -- Strix occidentalis caurina -- Vireo atricapilla -- contribuciones de vertedero -- dinámicas de fuente‐vertedero -- modelo espacialmente explícito basado en individuos -- persistencia poblacional -- trampas ecológicas -- Dipodomys ordii -- Strix occidentalis caurina -- Vireo atricapilla; Conservation biology -- Periodicals; 333.9516
• DOI: 10.1111/cobi.12540
• Languages: English
• ISSNs: 0888-8892

Abstract

Abstract: Population sinks present unique conservation challenges. The loss of individuals in sinks can compromise persistence; but conversely, sinks can improve viability by improving connectivity and facilitating the recolonization of vacant sources. To assess the contribution of sinks to regional population persistence of declining populations, we simulated source–sink dynamics for 3 very different endangered species: Black‐capped Vireos (Vireo atricapilla) at Fort Hood, Texas, Ord's kangaroo rats (Dipodomys ordii) in Alberta, and Northern Spotted Owls (Strix occidentalis caurina) in the northwestern United States. We used empirical data from these case studies to parameterize spatially explicit individual‐based models. We then used the models to quantify population abundance and persistence with and without long‐term sinks. The contributions of sink habitats varied widely. Sinks were detrimental, particularly when they functioned as strong sinks with few emigrants in declining populations (e.g., Alberta's Ord's kangaroo rat) and benign in robust populations (e.g., Black‐capped Vireos) when Brown‐headed Cowbird (Molothrus ater) parasitism was controlled. Sinks, including ecological traps, were also crucial in delaying declines when there were few sources (e.g., in Black‐capped Vireo populations with no Cowbird control). Sink contributions were also nuanced. For example, sinks that supported large, variable populations were subject to greater extinction risk (e.g., Northern Spotted Owls). In each of our case studies, new context‐dependent sinks emerged, underscoring the dynamic nature of sources and sinks and the need for frequent re‐assessment. Our results imply that management actions based on assumptions that sink habitats are generally harmful or helpful risk undermining conservation efforts for declining populations.