1 Contrasting changes in the abundance and diversity ofNorth american bird assemblages from 1971 to 2010 AAFKE M. SCHIPPER1,2, JONATHAN BELMAKER3, MURILO DANTAS DE MIRANDA4,5,LAETITIA M. NAVARRO4,5,KATRINB OHNING-GAESE6,7, MARK J. COSTELLO8,MARIA DORNELAS9, RUUD FOPPEN10,11, JOAQU IN H O R T A L12, ,2, BERTA MART IN - L OP E Z13, NATHALIE PETTORELLI14, CIBELEQUEIROZ15, , LUCA SANTINI17, KATJA SCHIFFERS6, ZORAN J. ,PIEROVISCONTI18,CARLORONDININI17andHENR IQUE M. PEREIRA4,5,191 Institute for Water and Wetland Research, Department of Environmental Science, Radboud University, PO Box 9010, 6500 GLNijmegen, The Netherlands,2 Netherlands Environmental Assessment Agency (PBL), PO Box 303, 3720 AH Bilthoven, TheNetherlands,3 Department of Zoology and the Steinhardt Museum of Natural History, George S.
2 Wise Faculty of Life Sciences, TelAviv University, Tel Aviv 69978, Israel,4 German Centre for Integrative Biodiversity Research (iDiv), Deutscher Platz 5e, 04103 Leipzig, Germany,5 Institute of Biology, Martin Luther University Halle Wittenberg, Am Kirchtor 1, 06108 Halle (Saale),Germany,6 Senckenberg Biodiversity and Climate Research Centre (BiK-F), Senckenberganlage 25, 60325 Frankfurt (Main),Germany,7 Institute for Ecology, Evolution & diversity ,Goethe University Frankfurt, Max von Laue Str. 13, 60439 Frankfurt(Main), Germany,8 Institute of Marine Science, University of Auckland, Auckland 1142, New Zealand,9 Centre for BiologicalDiversity, University of St Andrews, St Andrews KY16 9TH, Scotland,10 SOVON Dutch Centre for Field Ornithology, POBox 6521, 6503 GA, Nijmegen, The Netherlands,11 Institute for Water and Wetland Research, Department of Animal Ecology andPhysiology, Radboud University, PO Box 9010, 6500 GL Nijmegen, The Netherlands,12 Department of Biogeography and GlobalChange, Museo Nacional de Ciencias Naturales (MNCN-CSIC)
3 , C/Jos e Guti errez Abascal 2, 28006 Madrid, Spain,13 Institute ofEthics and Transdisciplinary Sustainability Research, Faculty of Sustainability, Leuphana University of L uneburg,Scharnhorststrasse 1, 21335 L uneburg, Germany,14 Institute of Zoology, Zoological Society of London, Regent s Park, NW1 4 RYLondon, UK,15 Stockholm Resilience Centre, Stockholm University, Kr aftriket 2B, 10691 Stockholm, Sweden,16 School of Biologicaland Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK,17 Global Mammal AssessmentProgram, Department of Biology and Biotechnologies, Sapienza Universit a di Roma, Viale dell Universit a 32, 00185 Rome, Italy,18 UNEP World Conservation Monitoring Centre, 219 Huntingdon Road, Cambridge CB3 0DL, UK,19 Infraestruturas de PortugalBiodiversity Chair, CIBIO/InBIO, Universidado do Porto, Campus Agr ario de Vair~ao, Rua Padre Armando Quintas 7, 4485-661 Vair~ao, PortugalAbstractAlthough it is generally recognized that global biodiversity is declining, few studies have examined long-term changes inmultiple biodiversity dimensions simultaneously.
4 In thisstudy, we quantified and compared temporal changes in theabundance, taxonomic diversity , functional diversity , and phylogenetic diversity of bird assemblages , using roadsidemonitoring data of the north american Breeding bird Survey from 1971 to 2010. We calculated 12 abundance and diver-sity metrics based on 5-year average abundances of 519 species for each of 768 monitoring routes. We did this for all birdspecies together as well as for four subgroups based on breeding habitat affinity (grassland, woodland, wetland, andshrubland breeders). The majority of the biodiversity metrics increased or remained constant over the study period,whereas the overall abundance of birds showed a pronounceddecrease, primarily driven by declines of the most abun-dant species.
5 These results highlight how stable or even increasing metrics of taxonomic,functional, or phylogeneticdiversity may occur in parallel with substantial losses of individuals. We further found that patterns of change differedamong the species subgroups, with both abundance and diversity increasing for woodland birds and decreasing forgrassland breeders. The Contrasting changes between abundance and diversity and among the breeding habitat groupsunderscore the relevance of a multifaceted approach to measuring biodiversity change . Our findings further stress theimportance of monitoring the overall abundance of individuals in addition to metrics of taxonomic, functional, or phylo-genetic diversity , thus confirming the importance of population abundance as an essential biodiversity : Aafke M.
6 Schipper, Institute for Water andWetland Research, Department of Environmental Science,Radboud University, PO Box 9010, 6500 GL Nijmegen, The Nether-lands, tel. +31 55461524, fax +31 703288799, e-mails: 2016 The change BiologyPublished by John Wiley & Sons is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use,distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial change Biology (2016), doi: :biodiversity change , biodiversity metrics, functional diversity (FD), phylogenetic diversity (PD), taxonomic diversity (TD), species abundanceReceived 13 October 2015 and accepted 5 March 2016 IntroductionIt is generally acknowledged that global biodiversity iscurrently declining at an unusually high rate (Barnoskyet al.)
7 , 2011; Pereiraet al., 2012; Tittensoret al., 2014).This decline includes local extirpations as well as com-plete extinctions of species and is so substantial that ithas been referred to as defaunation (Dirzoet al., 2014;McCauleyet al., 2015; Newboldet al., 2015). Nationaland international agreements to counteract this decline,like the Convention on Biological diversity (CBD), callfor biodiversity changes to be accurately quantified(Walpoleet al., 2009; Dornelaset al., 2013). So far, biodi-versity has typically been quantified based on taxo-nomic composition, using the number of species andtheir relative abundances to derive metrics like speciesrichness or Shannon s diversity index. However, as it isincreasingly recognized that taxonomic diversity repre-sents only one of the multiple dimensions of biodiver-sity, aspects of functional and phylogenetic diversityare increasingly included in biodiversity research andassessments (Purvis & Hector, 2000; Devictoret al.
8 ,2010; Wahlet al., 2011; Purschkeet al., 2013; Calbaet al.,2014; Monnetet al., 2014). Functional diversity repre-sents the distribution of the functional traits of theorganisms present in an assemblage (Vill egeret al.,2008). Functional traits are the morphological, physio-logical, or phenological characteristics of an organismthat strongly influence its performance (McGillet al.,2006; Lucket al., 2012). Hence, metrics of functionaldiversity are considered relevant particularly in thecontext of ecosystem functioning (Diaz & Cabido, 2001;Cardinaleet al., 2012). Phylogenetic diversity repre-sents the degree of evolutionary divergence of theorganisms within an assemblage (Faith, 1992). Metricsof phylogenetic diversity have been used as proxies forfunctional diversity as well as measures of conservationinterest on their own, representing the evolutionaryheritage and potential of species assemblages (Diazet al.
9 , 2013; Winteret al., 2013; Maceet al., 2014).Although no single metric can be expected to ade-quately describe the multidimensionality of biodiver-sity, at least some redundancy among the large varietyof metrics is likely, either for formal mathematical rea-sons or because different metrics may respond similarlyto environmental change . Hence, there is a clear needto identify a nonredundant yet representative set ofmetrics to adequately capture biodiversity change (Bucklandet al., 2005; Lyashevska & Farnsworth, 2012;Pereiraet al., 2013; Stevens & Tello, 2014). Yet, compar-ative assessments of temporal trends in multiple biodi-versity metrics have hardly been made (Magurranet al., 2010; Monnetet al., 2014). The few studiesconducted so far are inconclusive, as they show thattemporal changes may or may not be congruent amongtaxonomic, functional, and phylogenetic diversity (Petcheyet al.
10 , 2007; Winteret al., 2009; Vill egeret al.,2010; Monnetet al., 2014). Moreover, these studies allfocused on metrics reflecting species composition andignored the overall abundance of individuals, whichinfluences the organisms contribution to ecosystemfunctioning (McIntyreet al., 2007; Dirzoet al., 2014;Ingeret al., 2015). Hence, there is a clear need for com-parative studies of temporal changes in both the diver-sity of species assemblages and the overall abundanceof this study, we used large-scale and long-term birdmonitoring data in, to our knowledge, the largest com-parative assessment to date of temporal changes inabundance, taxonomic diversity , functional diversity ,and phylogenetic diversity . Birds provide an excellentcase to investigate biodiversity changes : They havebeen documented and studied more intensively thanmost other taxa, resulting in a relatively large availabil-ity of monitoring data as well as information on func-tional traits and phylogeny (Gregoryet al.