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The costs of mischoosing are not uniform across individuals


Matching habitat choice is a particular form of habitat selection based on self?assessment of local performance that offers individuals a means to optimize the match of phenotype to the environment. Despite the advantages of this mechanism in terms of increased local adaptation, examples from natural populations are extremely rare. One possible reason for the apparent rarity of matching habitat choice is that it might be manifest only in those segments of a population for which the cost of a phenotype–environment mismatch is high. To test this hypothesis, we used a breeding population of sockeye salmon (Oncorhynchus nerka) exposed to size-dependent predation risk by bears, and evaluated the costs of mischoosing in discrete groups (e.g. male versus females, and ocean?age 2 versus ocean?age 3) using reproductive life span as a measure of individual performance. Bear preference for larger fish, especially in shallow water, translates into a performance trade-off that sockeye salmon can potentially use to guide their settlement decisions. Consistent with matching habitat choice, we found that salmon of similar ocean?age and size tended to cluster together in sites of similar water depth. However, matching habitat choice was only favoured in 3?ocean females – the segment of the population most vulnerable to bear predation. This study illustrates the unequal relevance of matching habitat choice to different segments of a population, and suggests that ‘partial matching habitat choice' could have resulted in an underestimation of the actual prevalence of this mechanism in nature. informacion[at] Camacho & Hendry (2020) Matching habitat choice: it's not for everyone. Oikos DOI 10.1111/oik.06932
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Landscape change promotes the emergence of a rare predator-prey interaction

Landscape change promotes the emergence of a rare predator-prey interaction

Diet studies provide basic natural history information to understand food web dynamics. However, measuring the dietary breadth of rare, elusive species is extremely challenging due to their scarcity and/or cryptic behavior. Here, for the first time, an uncommon predatory interaction –nest predation– between two of the most elusive and rare species in Europe, the Iberian lynx and the red-necked nightjar is documented. Data on individually tagged nightjars and photo-traps were analysed together to investigate the underlying conditions that might have facilitated the fatal encounter. Human-induced changes in the landscape in 2014–2016 forced nightjars to travel relatively large distances (1–2 km) from the nest to find food, which translated into considerably longer nest absences compared with previous years (2011?2012). This fact, together with a drastic decline in wild rabbit populations, the main prey of lynx, might lead lynxes to search for alternative food resources, such as unconcealed –and easily detectable– bird nests. These results provide new data about the trophic ecology of this threatened predator and suggest that anthropogenic landscape changes may affect predator-prey relationships in unexpected ways. informacion[at] Sáez-Gómez et al (2018) Landscape change promotes the emergence of a rare predator-prey interaction. Food Webs