Factors affecting the distribution of haemosporidian parasites within an oceanic island.
Understanding how different ecological and evolutionary processes influence the distribution of pathogens within the environment is important from many perspectives including wildlife epidemiology, evolutionary ecology and conservation. The simultaneous use of ecological and evolutionary frameworks can enhance our conceptual understanding of host-parasite interactions, however such studies are rare in the wild. Using samples from 12 bird species caught across all habitats existing on an oceanic island, we evaluated how environmental variables, parasite host specificity and parasite phylogenetic relationships determine the distribution and prevalence of haemosporidians (Haemoproteus, Plasmodium and Leucocytozoon) in the wild living avifauna. Differences were found in the prevalence of Plasmodium, but not Leucocytozoon, strains between habitats. The warmest temperature best predicted Plasmodium prevalence in the low altitude habitats, which had the highest incidence of Plasmodium. The prevalence of Leucocytozoon lineages was associated with natural factors, i.e. rainfall, temperature and habitat, but the two most important predictors (from model averaging) for models of Leucocytozoon were anthropogenic: poultry farms and distance to a water reservoir. We found no relationship between local (Tenerife, Canary Islands) versus global host range indices (which assess the diversity of hosts that a parasite is observed to infect), thus global generalist lineages do not behave in the same way on Tenerife (i.e. they infected less avian hosts than was expected). Phylogenetic analysis revealed that the most abundant haemosporidians on Tenerife grouped with lineages found in African host species. Our data indicate that climatic and anthropogenic factors, plus proximity to the African mainland, are the main factors influencing the presence and distribution of avian haemosporidians on Tenerife. Future climate projections for the archipelago foresee significant temperature increases which would, given our results, increase rates of Plasmodium infection in bird species in all habitats. Such patterns could be of concern if those increase mortality rates in the unique avifauna of these islands.
School of Biological Sciences, University of East Anglia, Norwich, UK; Island Ecology and Evolution Research Group, IPNA-CSIC, Tenerife, Canary Islands, Spain; Abeque Association, Tenerife, Canary Islands, Spain.
David P
DP
Padilla
Research Unit of Biodiversity, Oviedo University, Mieres, Asturias, Spain. Electronic address: illerajuan@uniovi.es.
Juan Carlos
JC
Illera
School of Biological Sciences, University of East Anglia, Norwich, UK; Grupo Ecología y Evolución de Vertebrados, Instituto de Biología, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia, Medellín, Colombia.
Catalina
C
Gonzalez-Quevedo
Abeque Association, Tenerife, Canary Islands, Spain.
Miry
M
Villalba
School of Biological Sciences, University of East Anglia, Norwich, UK.
David S
DS
Richardson
D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology / Q000469:parasitology; D001717:Birds; D017753:Ecosystem; D004781:Environmental Exposure; D016787:Haemosporida / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D058507:Host Specificity; D058974:Phylogeography; D015995:Prevalence; D011528:Protozoan Infections / Q000453:epidemiology / Q000469:parasitology; D013030:Spain / Q000453:epidemiology
Avian haemosporidian; Canary Islands; Community level; Environmental variables; Host specificity; Oceanic islands; Parasite biogeography