Global distribution of a key trophic guild contrasts with common latitudinal diversity patterns

Authors

  • Luz Boyero,

    1. Wetland Ecology Department, Doñna Biological Station-CSIC, Avda Americo Vespucio sn/n, E-41092 Sevilla, Spain
    2. School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811 Australia
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  • Richard G Pearson,

    1. School of Marine and Tropical Biology, James Cook University, Townsville, Queensland 4811 Australia
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  • David Dudgeon,

    1. School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
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  • Manuel A. S Graça,

    1. IMAR-CMA and Department Life Sciences, University of Coimbra, 3001 401 Coimbra, Portugal
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  • Mark O Gessner,

    1. Department of Aquatic Ecology, Eawag: Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland
    2. Institute of Integrative Biology (IBZ), ETH Zurich, 8092 Zurich, Switzerland
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    • Present address: Department of Stratified Lakes, Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, 16775 Stechlin, Germany, and Department of Ecology, Berlin Institute of Technology (TU Berlin), Ernst-Reuter-Platz 1, 10587 Berlin, Germany.

  • Ricardo J Albariño,

    1. Laboratorio de Limnología, INIBIOMA, Universidad Nacional del Comahue-CONICET, Bariloche, Argentina
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  • Verónica Ferreira,

    1. IMAR-CMA and Department Life Sciences, University of Coimbra, 3001 401 Coimbra, Portugal
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  • Catherine M Yule,

    1. School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, 46150, Selangor, Malaysia
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  • Andrew J Boulton,

    1. Ecosystem Management, School of Environmental and Rural Science, University of New England, Armidale, NSW 2350, Australia
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  • Muthukumarasamy Arunachalam,

    1. Sri Paramakalyani Centre for Environmental Sciences, Manonmainam Sundaranar University, Alwarkuruchi, Tamil Nadu, India
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  • Marcos Callisto,

    1. Laboratório de Ecologia de Bentos, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, CP 486, CEP 30.161-970, Belo Horizonte MG, Brazil
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  • Eric Chauvet,

    1. Université de Toulouse, INP, UPS, EcoLab (Laboratoire Écologie Fonctionnelle et Environnement), 118 Route de Narbonne, 31062 Toulouse, France
    2. CNRS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 Route de Narbonne, 31062 Toulouse, France
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  • Alonso Ramírez,

    1. Institute for Tropical Ecosystem Studies, University of Puerto Rico, P.O. Box 70377, San Juan, Puerto Rico 00936 USA
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  • Julián Chará,

    1. Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria, CIPAV, Carrera 25 No. 6-62, Cali, Colombia
    2. Centro de Investigaciones y Estudios en Biodiversidad y Recursos Genéticos, CIEBREG, POB 97, Pereira, Colombia
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  • Marcelo S Moretti,

    1. Laboratório de Ecologia de Bentos, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, CP 486, CEP 30.161-970, Belo Horizonte MG, Brazil
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    • Present address: Centro Universitário Vila Velha, Programa de Pós Graduação em Ecologia de Ecossistemas, 29102 770, Vila Velha, ES, Brazil.

  • José F Gonçalves Jr,

    1. Laboratório de Ecologia de Bentos, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, CP 486, CEP 30.161-970, Belo Horizonte MG, Brazil
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    • Present address: Laboratório de Limnologia, Departamento de Ecologia, IB, Universidade de Brasília, 70910 900, Brasília, DF, Brazil.

  • Julie E Helson,

    1. Surface and Groundwater Ecology Research Group, Department of Biological Sciences, University of Toronto at Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4 Canada
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  • Ana M Chará-Serna,

    1. Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria, CIPAV, Carrera 25 No. 6-62, Cali, Colombia
    2. Departamento de Biología, Grupo de Investigaciones Entomológicas, Universidad del Valle, Apartado Aéreo 25360, Cali, Colombia
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  • Andrea C Encalada,

    1. IMAR-CMA and Department Life Sciences, University of Coimbra, 3001 401 Coimbra, Portugal
    2. Colegio de Ciencias Biológicas y Ambientales, Universidad San Francisco de Quito, Campus Cumbayá, P.O. Box 17 1200 841, Quito, Ecuador
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  • Judy N Davies,

    1. Ecosystem Management, School of Environmental and Rural Science, University of New England, Armidale, NSW 2350, Australia
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  • Sylvain Lamothe,

    1. Université de Toulouse, INP, UPS, EcoLab (Laboratoire Écologie Fonctionnelle et Environnement), 118 Route de Narbonne, 31062 Toulouse, France
    2. CNRS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 Route de Narbonne, 31062 Toulouse, France
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  • Aydeè Cornejo,

    1. Sección de Entomología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Avenida Justo Arosemena y Calle 35, 0816 02593, Panama City, Panama
    2. Programa Centroamericano de Maestría en Entomología, Universidad de Panamá, Panama City, Panama
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  • Aggie O. Y Li,

    1. School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
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  • Leonardo M Buria,

    1. Laboratorio de Limnología, INIBIOMA, Universidad Nacional del Comahue-CONICET, Bariloche, Argentina
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  • Verónica D Villanueva,

    1. Laboratorio de Limnología, INIBIOMA, Universidad Nacional del Comahue-CONICET, Bariloche, Argentina
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  • María C Zúñiga,

    1. Centro para la Investigación en Sistemas Sostenibles de Producción Agropecuaria, CIPAV, Carrera 25 No. 6-62, Cali, Colombia
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  • Catherine M Pringle

    1. Odum School of Ecology, The University of Georgia, Athens, Georgia 30602-2602 USA
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Abstract

Most hypotheses explaining the general gradient of higher diversity toward the equator are implicit or explicit about greater species packing in the tropics. However, global patterns of diversity within guilds, including trophic guilds (i.e., groups of organisms that use similar food resources), are poorly known. We explored global diversity patterns of a key trophic guild in stream ecosystems, the detritivore shredders. This was motivated by the fundamental ecological role of shredders as decomposers of leaf litter and by some records pointing to low shredder diversity and abundance in the tropics, which contrasts with diversity patterns of most major taxa for which broad-scale latitudinal patterns haven been examined. Given this evidence, we hypothesized that shredders are more abundant and diverse in temperate than in tropical streams, and that this pattern is related to the higher temperatures and lower availability of high-quality leaf litter in the tropics. Our comprehensive global survey (129 stream sites from 14 regions on six continents) corroborated the expected latitudinal pattern and showed that shredder distribution (abundance, diversity and assemblage composition) was explained by a combination of factors, including water temperature (some taxa were restricted to cool waters) and biogeography (some taxa were more diverse in particular biogeographic realms). In contrast to our hypothesis, shredder diversity was unrelated to leaf toughness, but it was inversely related to litter diversity. Our findings markedly contrast with global trends of diversity for most taxa, and with the general rule of higher consumer diversity at higher levels of resource diversity. Moreover, they highlight the emerging role of temperature in understanding global patterns of diversity, which is of great relevance in the face of projected global warming.

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