title: The malagarasi river does not form an absolute barrier to chimpanzee movement in Western Tanzania.
abstract: The Malagarasi River has long been thought to be a barrier to chimpanzee movements in western Tanzania. This potential geographic boundary could affect chimpanzee ranging behavior, population connectivity and pathogen transmission, and thus has implications for conservation strategies and government policy. Indeed, based on mitochondrial DNA sequence comparisons it was recently argued that chimpanzees from communities to the north and to the south of the Malagarasi are surprisingly distantly related, suggesting that the river prevents gene flow. To investigate this, we conducted a survey along the Malagarasi River. We found a ford comprised of rocks that researchers could cross on foot. On a trail leading to this ford, we collected 13 fresh fecal samples containing chimpanzee DNA, two of which tested positive for SIVcpz. We also found chimpanzee feces within the riverbed. Taken together, this evidence suggests that the Malagarasi River is not an absolute barrier to chimpanzee movements and communities from the areas to the north and south should be considered a single population. These results have important consequences for our understanding of gene flow, disease dynamics and conservation management.
authors.affiliation: Department of Anthropology, University of California San Diego, San Diego, California, United States of America. akp34@cam.ac.uk
authors.forename: Alex K
authors.initials: AK
authors.lastname: Piel
authors.forename: Fiona A
authors.initials: FA
authors.lastname: Stewart
authors.forename: Lilian
authors.initials: L
authors.lastname: Pintea
authors.forename: Yingying
authors.initials: Y
authors.lastname: Li
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Ramirez
authors.forename: Dorothy E
authors.initials: DE
authors.lastname: Loy
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Crystal
authors.forename: Gerald H
authors.initials: GH
authors.lastname: Learn
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Knapp
authors.forename: Paul M
authors.initials: PM
authors.lastname: Sharp
authors.forename: Beatrice H
authors.initials: BH
authors.lastname: Hahn
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial; D005260:Female; D005843:Geography; D008297:Male; D002679:Pan troglodytes / Q000145:classification / Q000235:genetics / Q000821:virology; D010802:Phylogeny; D011157:Population Dynamics; D045483:Rivers; D016097:Simian Acquired Immunodeficiency Syndrome / Q000635:transmission / Q000821:virology; D015302:Simian Immunodeficiency Virus; D013636:Tanzania
chemical_list: D004272:DNA, Mitochondrial
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