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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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The European trade ban on wild birds reduced invasion risks

The European trade ban on wild birds reduced invasion risks

International wildlife trade is a major source of current biological invasions. However, the power of trade regulations to reduce invasion risks at large, continental scales has not been empirically assessed. Although international policy responses to combat biological invasions have increased over the last several decades, responsibility for protection against invaders lies mostly on national governments. This has led to important differences in legislation among countries, reducing the invasion likelihood in countries or regions of implementation, but not tackling the problem of invasive species as a global issue, as risky species can still be exported to other countries. The European wild bird trade ban was implemented in 2005 to counter the spread of the avian flu. If the ban reduced invasion risk was tested in two European countries, where 398 nonnative bird species were introduced into the wild from 1912 to 2015. The number of newly introduced species per year increased exponentially until 2005 (in parallel with the volume of wild bird importations), and then sharply decreased in subsequent years. Interestingly, a rapid trade shift from wild?caught birds to captive?bred birds, which have lower invasive potential than wild?caught birds, allowed the maintenance of bird availability in markets. Results demonstrate the effectiveness of a trade ban for preventing biological invasions without impacting the ability to meet societal demands. informacion[at] Cardador et al (2019) The European trade ban on wild birds reduced invasion risks. Conserv Lett