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Fitness consequences of different migratory strategies in partially migratory populations: a multi-taxa meta-analysis
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Orientador(es)
Resumo(s)
1. Partial migration—wherein migratory and non-migratory individuals exist within
the same population—represents a behavioural dimorphism; for it to persist over
time, both strategies should yield equal individual fitness. This balance may be
maintained through trade-offs where migrants gain survival benefits by avoiding
unfavourable conditions, while residents gain breeding benefits from early access
to resources.
2. There has been little overarching quantitative analysis of the evidence for this
fitness balance. As migrants—especially long-distance migrants—may be particularly
vulnerable to environmental change, it is possible that recent anthropogenic
impacts could drive shifts in fitness balances within these populations.
3. We tested these predictions using a multi-taxa meta-analysis. Of 2,939 reviewed
studies, 23 contained suitable information for meta-analysis, yielding 129 effect
sizes.
4. Of these, 73% (n = 94) r eported h igher r esident f itness, 2 2% (n = 28) reported
higher migrant fitness, and 5% (n = 7) reported equal fitness. Once weighted for
precision, we found balanced fitness benefits across the entire dataset, but a consistently
higher fitness of residents over migrants in birds and herpetofauna (the
best-sampled groups). Residency benefits were generally associated with survival,
not breeding success, and increased with the number of years of data over which
effect sizes were calculated, suggesting deviations from fitness parity are not due
to sampling artefacts.
5. A pervasive survival benefit to residency documented in recent literature could
indicate that increased exposure to threats associated with anthropogenic change
faced by migrating individuals may be shifting the relative fitness balance between
strategies
Descrição
Review
Palavras-chave
behavioural dimorfism climate change evolution of migration migratory strategy movement ecology partial migration
Contexto Educativo
Citação
J Anim Ecol. 2019;00:1–13
Editora
British Ecological Society