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The costs of mischoosing are not uniform across individuals

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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]ebd.csic.es: Camacho & Hendry (2020) Matching habitat choice: it's not for everyone. Oikos DOI 10.1111/oik.06932


https://onlinelibrary.wiley.com/doi/full/10.1111/oik.06932
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Firebreaks constrain butterfly movements

Firebreaks constrain butterfly movements

Firebreaks are linear strips that dissect the landscape and prevent or mitigate the spread of wildfires in Mediterranean landscapes. However, few studies have addressed their potential effect on insect behavior. The lack of traffic and other human activities in firebreaks makes them suitable for testing the sole effect of physical habitat disruption on animal movement. Main objective was to evaluate whether the pattern of movement by a butterfly species was affected by this landscape element. Flight trajectories of the lycaenid butterfly Plebejus argus were reconstructed within and around one firebreak using visual and GPS tracking in Doñana National Park (southern Spain). Butterflies that were active at the firebreak boundary often refused to enter the firebreak and, when they did, most individuals returned before reaching the opposite side. Inside the firebreak faster and straighter trajectories were recorded than in adjacent scrubland areas. Butterflies that crossed the firebreak headed the most favorable direction to minimize the time spent within the habitat discontinuity. At the landscape scale, firebreak density increased in areas where P. argus habitat was more fragmented and had lower quality. In other studies, when firebreaks are mowed instead of ploughed, they appeared to be beneficial for butterflies. In contrast, in Doñana, barren firebreaks do not provide any valuable resource for P. argus and its environmental conditions probably entail considerable physiological stress. In sum, a narrow, open linear element lacking any human activity induces a marked change in the movement behavior of a butterfly species, with potential consequences on population dynamics at the landscape scale. Therefore, firebreaks used for protecting Mediterranean landscapes could have side effects on animal populations other than localized habitat loss due to mere vegetation removal. informacion[at]ebd.csic.es: Fernández et al (2019) Firebreaks as a barrier to movement: the case of a butterfly in a Mediterranean landscape. J Insect Conserv DOI 10.1007/s10841-019-00175-5


https://link.springer.com/article/10.1007%2Fs10841-019-00175-5#Abs1