title: Environmental controls on the distribution and diversity of lentic Chironomidae (Insecta: Diptera) across an altitudinal gradient in tropical South America.
abstract: To predict the response of aquatic ecosystems to future global climate change, data on the ecology and distribution of keystone groups in freshwater ecosystems are needed. In contrast to mid- and high-latitude zones, such data are scarce across tropical South America (Neotropics). We present the distribution and diversity of chironomid species using surface sediments of 59 lakes from the Andes to the Amazon (0.1-17°S and 64-78°W) within the Neotropics. We assess the spatial variation in community assemblages and identify the key variables influencing the distributional patterns. The relationships between environmental variables (pH, conductivity, depth, and sediment organic content), climatic data, and chironomid assemblages were assessed using multivariate statistics (detrended correspondence analysis and canonical correspondence analysis). Climatic parameters (temperature and precipitation) were most significant in describing the variance in chironomid assemblages. Temperature and precipitation are both predicted to change under future climate change scenarios in the tropical Andes. Our findings suggest taxa of Orthocladiinae, which show a preference to cold high-elevation oligotrophic lakes, will likely see range contraction under future anthropogenic-induced climate change. Taxa abundant in areas of high precipitation, such as Micropsectra and Phaenopsectra, will likely become restricted to the inner tropical Andes, as the outer tropical Andes become drier. The sensitivity of chironomids to climate parameters makes them important bio-indicators of regional climate change in the Neotropics. Furthermore, the distribution of chironomid taxa presented here is a vital first step toward providing urgently needed autecological data for interpreting fossil chironomid records of past ecological and climate change from the tropical Andes.
authors.affiliation: Environment, Earth & Ecosystems The Open University Walton Hall Milton Keynes MK76AA UK.
authors.forename: Frazer
authors.initials: F
authors.lastname: Matthews-Bird
authors.affiliation: Environment, Earth & Ecosystems The Open University Walton Hall Milton Keynes MK76AA UK; Palaeoecology & Landscape Ecology Institute of Biodiversity & Ecosystem Dynamics (IBED) University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands.
authors.forename: William D
authors.initials: WD
authors.lastname: Gosling
authors.affiliation: Environment, Earth & Ecosystems The Open University Walton Hall Milton Keynes MK76AA UK.
authors.forename: Angela L
authors.initials: AL
authors.lastname: Coe
authors.affiliation: Biological Sciences Florida Institute of Technology 150 West University Boulevard Melbourne Florida 32901.
authors.forename: Mark
authors.initials: M
authors.lastname: Bush
authors.affiliation: Department of Geography and Environmental Science (SAGES) Centre for Past Climate Change University of Reading Reading RG6 6AB UK.
authors.forename: Francis E
authors.initials: FE
authors.lastname: Mayle
authors.affiliation: Department of Earth and Planetary Sciences Northwestern University 2145, Sheridan Road Evanston Illinois 60201.
authors.forename: Yarrow
authors.initials: Y
authors.lastname: Axford
authors.affiliation: Department of Life Sciences Natural History Museum Cromwell Road London SW7 5BD UK.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Brooks
keywords: Andes; chironomids; climate change; diversity; lakes
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