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Abstract Marine resource subsidies alter consumer dynamics of recipient populations in coastal systems. The response to these subsidies by generalist consumers is often not uniform, creating inter- and intrapopulation diet variation and niche diversification that may be intensified across heterogeneous landscapes. We sampled western fence lizards,Sceloporus occidentalis, from Puget Sound beaches and coastal and inland forest habitats, in addition to the lizards’ marine and terrestrial prey items to quantify marine and terrestrial resource use with stable isotope analysis and mixing models. Beach lizards had higher average δ13C and δ15N values compared to coastal and inland forest lizards, exhibiting a strong mixing line between marine and terrestrial prey items. Across five beach sites, lizard populations received 20–51% of their diet from marine resources, on average, with individual lizards ranging between 7 and 86% marine diet. The hillslope of the transition zone between marine and terrestrial environments at beach sites was positively associated with marine-based diets, as the steepest sloped beach sites had the highest percent marine diets. Within-beach variation in transition zone slope was positively correlated with the isotopic niche space of beach lizard populations. These results demonstrate that physiography of transitional landscapes can mediate resource flow between environments, and variable habitat topography promotes niche diversification within lizard populations. Marine resource subsidization of Puget Sound beachS. occidentalispopulations may facilitate occupation of the northwesternmost edge of the species range. Shoreline restoration and driftwood beach habitat conservation are important to support the unique ecology of Puget SoundS. occidentalis.
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Using mangrove and field observation data to identify fine-scale species distributions: a case study in bockadams (Serpentes: Homalopsidae: Cerberus )
Characterization of species distributions is a fundamental challenge in biodiversity science, with particular significance for downstream evolutionary studies, conservation efforts, field-based faunal studies and estimates of species diversity. Checklists and phylogenetic studies often focus on poorly known, rare taxa with limited ranges. However, studies of widely distributed, ecologically important species that are abundant in their preferred microhabitats are also important for systematics and local conservation efforts, but less often studied. We collected novel natural history data during fieldwork (2019–2023) for Philippine populations of bockadams (Homalopsidae:Cerberus), one of the most abundant vertebrates in Southeast Asian aquatic systems. Considered a coastal snake, many studies reportCerberusinland. We report the frequency of encounters ofCerberus schneiderii, and the IUCN data-deficient, Philippine-endemicCerberus microlepisduring six expeditions (62 days; 1041 person-hours). We report new occurrence data for 69C. schneideriiand6 C. microlepisfor coastal and inland populations, water measurements and dietary observations. Regression analyses and ecological niche models show the importance of coastal and mangrove habitats forCerberus. Our study is the most comprehensive assessment of PhilippineCerberuspopulations to date and provides critical baseline natural history data for downstream research on widespread and range-restricted species of Southeast Asian snakes.
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- PAR ID:
- 10566808
- Publisher / Repository:
- Royal Society Open Science
- Date Published:
- Journal Name:
- Royal Society Open Science
- Volume:
- 11
- Issue:
- 10
- ISSN:
- 2054-5703
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1098/rsos.240483
