‘Chancing on a spectacle:’ co‐occurring animal migrations and interspecific interactions

Abstract

Migrations of diverse wildlife species often converge in space and time, with their journeys shaped by similar forces (i.e. geographic barriers and seasonal resources and conditions); we term this ‘co‐migration’. Recent studies have illuminated multi‐speciesmigrations by land and sea including the simultaneous movements of numerous insects, birds, bats and of fish invertebrates marine predators. Beyond their significance as natural wonders, species with overlapping migrations may interact ecologically, with potential effects on population and community dynamics. Direct and indirect ecological interactions (including predation and competition) between migrant species remain poorly understood, in part because migration is the least‐studied phase of animals’ annual cycles. To address this gap, we conducted a literature review to examine whether animal migration studies incorporate multiple species and to what extent they investigate interspecific interactions between co‐migrants. Following a key word search, we read all migration research papers in 23 relevant peer‐reviewed journals during 2008–2017. Thirty percent of animal migration papers reported two or more species with coinciding migrations, suggesting that co‐migrations are common, although few studies investigated or discussed these mixed‐species migrations further. Synthesizing these, we present examples and describe five types of ecological interactions between migrating species, including predator–prey, host–parasite and commensal relationships. Considering migratory animals as interacting with migrant communities will enhance understanding of the drivers of migration and could improve predictions about wildlife responses to global change. Further research focused on multi‐species migrations could also inform conservation efforts for migratory animal populations, many of which are declining or shifting, with unexplored consequences for other co‐migratory species.

A place to land: spatiotemporal drivers of stopover habitat use by migrating birds

“…Our results can serve as baselines for measurement of effectiveness of future management and conservation efforts on densities of migrating birds. As declines of most migratory bird species outpace current management interventions (Rosenberg et al ., 2019), we identify convergence at ‘migratory hotspots’ where targeted management efforts could uniquely benefit the declining abundance of migratory communities (Cohen and Satterfield, 2020).…”

Pollination by hoverflies in the Anthropocene

“…R. Soc. B 287: 20200508 in communities being dominated by more generalist species, mobile migratory species [108], or change overwintering dynamics [109,110] and as yet we have little appreciation for how this may influence the stability of pollinator communities and the pollination functions they provide. As such, there is a need for further research to determine the response of hoverfly communities to anthropogenic perturbation.…”

Modularity in temporal co-occurrence networks at a stopover site reveals strong co-migration fidelity in African-European migratory landbirds over time

“…The copyright holder for this preprint this version posted February 19, 2022. ; https://doi.org/10.1101/2022.02.17.480723 doi: bioRxiv preprint 6 Migrations involve the simultaneous movement of multiple species at once, connecting widely separated and diverse communities potentially having a strong impact on the dynamic and stability of ecosystems. Migratory routes of different species often converge both in space and time (i.e., co-migration, sensu Cohen & Satterfield, 2020), creating the conditions for the emergence of direct and indirect ecological interactions, including competition, predation, facilitation and even social interactions (Cohen & Satterfield, 2020). For instance, studies have shown how the dynamic and prevalence of parasites transmission, as well as transient dynamics in lake ecosystems, can be somehow related to migration timing (Brodersen et al, 2008;Peacock et al, 2020).…”

“…Investigating the causes and the effects of changing migration phenology from a community point of view entails inherent difficulties associated with the need to constantly track and monitor animals across oceans and continents (Cohen & Satterfield, 2020). A further source of uncertainty derives from the need to Furthermore, Montaño-Centellas (2020) used spatial data to build and explore co-occurrence networks of avian mixed-species flocks across elevation gradients, identifying changes in interactions as the main driver of species turnover of Andean flocking birds.…”