title: Coupled range dynamics of brood parasites and their hosts responding to climate and vegetation changes.
abstract: As populations shift their ranges in response to global change, local species assemblages can change, setting the stage for new ecological interactions, community equilibria and evolutionary responses. Here, we focus on the range dynamics of four avian brood parasite species and their hosts in southern Africa, in a context of bush encroachment (increase in woody vegetation density in places previously occupied by savanna-grassland mosaics) favouring some species at the expense of others. We first tested whether hosts and parasites constrained each other's ability to expand or maintain their ranges. Secondly, we investigated whether range shifts represented an opportunity for new host-parasite and parasite-parasite interactions. We used multispecies dynamic occupancy models with interactions, fitted to citizen science data, to estimate the contribution of interspecific interactions to range shifts and to quantify the change in species co-occurrence probability over a 25-year period. Parasites were able to track their hosts' range shifts. We detected no deleterious effect of the parasites' presence on either the local population viability of host species or the hosts' ability to colonize newly suitable areas. In the recently diversified indigobird radiation (Vidua spp.), following bush encroachment, the new assemblages presented more potential opportunities for speciation via host switch, but also more potential for hybridization between extant lineages, also via host switch. Multispecies dynamic occupancy models with interactions brought new insights into the feedbacks between range shifts, biotic interactions and local demography: brood parasitism had little detected impact on extinction or colonization processes, but inversely the latter processes affected biotic interactions via the modification of co-occurrence patterns.
authors.affiliation: Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Rondebosch, 7701, Cape Town, South Africa.|Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, VA, 22630, USA.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Péron
authors.affiliation: Statistics in Ecology, Environment and Conservation, Department of Statistical Sciences, University of Cape Town, Rondebosch, 7701, Cape Town, South Africa.|African Climate and Development Initiative, University of Cape Town, Rondebosch, 7701, South Africa.
authors.forename: Res
authors.initials: R
authors.lastname: Altwegg
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK.
authors.forename: Gabriel A
authors.initials: GA
authors.lastname: Jamie
authors.affiliation: Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK.|Department of Science and Technology-National Research Foundation Centre of Excellence, Percy FitzPatrick Institute, University of Cape Town, Rondebosch, 7701, South Africa.
authors.forename: Claire N
authors.initials: CN
authors.lastname: Spottiswoode
mesh_terms: D000349:Africa; D063147:Animal Distribution; D000818:Animals; D001717:Birds / Q000469:parasitology* / Q000502:physiology*; D057231:Climate Change; D017753:Ecosystem; D006790:Host-Parasite Interactions; D009425:Nesting Behavior
keywords: brood parasitism; bush encroachment; climate change; honeyguide; indigobird; range overlap; species distribution models