The Condor 108:778–791 # The Cooper Ornithological Society 2006 CLIMATE CHANGE EFFECTS ON NEOTROPICAL MANAKIN DIVERSITY BASED ON ECOLOGICAL NICHE MODELING MARINA ANCIA˜ ES1 AND A. TOWNSEND PETERSON Natural History Museum and Biodiversity Research Center, 1345 Jayhawk Blvd., University of Kansas, Lawrence, KS 66045-7561 Abstract. Assessing the nature and magnitude of potential effects of climate change on populations is important to anticipating effects on species diversity for conservation planning. We used ecological niche modeling to predict present and future distributions of 49 species of manakins (Pipridae) and allies. Predictions for present-day distributions were highly coincident with independent test data, suggesting good predictive ability. Assuming no dispersal, projections of potential distributions under four scenarios of climate change predicted that 20% of manakin species would likely go extinct from their current ranges, and that distributions would in general be reduced and fragmented, regardless of the area of present-day potential distribution or rarity. Predicted changes in potential distributions, spatial configuration of suitable habitats, and geographic position of species ranges were more dramatic for species inhabiting flatlands than for montane species. These results are an example of how ecological niche modeling techniques can anticipate the nature and magnitude of changes in biodiversity in response to climate change. Key words: climate change, conservation, ecological niche, geographic distribution, manakin. Efeitos de Mudanc¸as Clima´ticas na Diversidade de Tangara´s Neotropicais Estimados Atrave´s da Modelagem de Nicho Ecolo´gico Resumo. Conhecer a natureza e magnitude dos efeitos potenciais das mudanc¸as clima´ticas em populac¸o˜ese´ importante em planos de conservac¸a˜o por antecipar os efeitos sobre a diversidade de espe´cies de uma regia˜o. Modelamos o nicho ecolo´gico de 49 espe´cies de tangara´s (Pipridae), e espe´cies aparentadas, para prever suas distribuic¸o˜es no presente e futuro. Estimativas para o presente foram altamente coincidentes com testes independentes, indicando boa previsibilidade dos modelos. As projec¸o˜es de distribuic¸o˜es potenciais em quatro cena´rios de mudanc¸as clima´ticas indicam que, na auseˆncia de dispersa˜o, 20% das espe´cies de tangara´s ira˜o se extinguir de suas localidades de ocorreˆncia atuais, e que suas distribuic¸o˜es se tornara˜o reduzidas e fragmentadas, independentemente da a´rea de distribuic¸a˜o potencial e raridade no presente. Mudanc¸as previstas na distribuic¸a˜o potencial, disposic¸a˜o espacial de habitats propı´cios, e posic¸a˜o geogra´fica da distribuic¸a˜o de espe´cies foram maiores para espe´cies habitantes de baixadas que de regio˜es montanhosas. Estes resultados exemplificam o uso de modelagem de nicho ecolo´gico para antecipar a natureza e magnitude de alterac¸o˜es na biodiversidade decorrentes de mudanc¸as clima´ticas. INTRODUCTION of precipitation for coming decades in Neo- Globally, climates are undergoing dramatic tropical regions has generated concern about changes (Karl et al. 1996, Magnuson 2001), consequences for biodiversity across the region (Houghton et al. 2001), where numerous bio- with demonstrable effects on the distribution of diversity hotspots are located (Myers et al. biodiversity, including both colonization of new 2000). Thus, as future climate changes will areas and local extinctions (Brown et al. 1997, likely affect the conservation status of many Parmesan et al. 1999, Xu and Yan 2001, species (Peters and Darling 1985, Dobson et al. Walther et al. 2002). Predictions of substantial 1989, Peters and Myers 1991–1992, Chapin et further warming and reorganization of patterns al. 2000, Thomas et al. 2004), studies that anticipate the pattern and magnitude of effects Manuscript received 17 November 2005; accepted of climate change on distributions of Neotrop- 6 June 2006. ical species are urgently needed. 1 Present address: Curadoria de Aves, Instituto Nacional de Pesquisas da Amazoˆnia, INPA. Av. The geographic distributions of species are Andre´ Arau´jo 2936 C.P. 478 Aleixo, Manaus, AM defined by autecological needs and tolerances, 69083 Brazil. E-mail: [email protected] biotic interactions, and historical effects (So- [778] MANAKIN DIVERSITY UNDER FUTURE CLIMATES 779 bero´n and Peterson 2005). As such, climate forests and other tropical forests. Additionally, change may affect the spatial manifestation of manakins are easily collected, and so are well- ecological niches (i.e., the set of environmental represented in collections. Ecological niches are conditions within which a species is able to generally conserved among sister manakin maintain populations without immigration; species, suggesting ecological conservativism Grinnell 1917, 1924). When faced with chang- across lineages (MA and ATP, unpubl. data). ing ecological conditions, species may track The Neotropical manakins are therefore an appropriate conditions or adapt to the new ideal group for examining the consequences of conditions; failing both, populations will be predicted future climate changes on the distri- extirpated (Holt 1990, Brown and Lomolino bution of Neotropical biodiversity. Here, we 1998). As both theoretical expectations and model ecological niches and predict future empirical studies suggest that ecological niches potential geography of Neotropical manakins remain relatively constant over long time scales in the face of changing climates over coming (Huntley et al. 1989, Kawecki and Stearns 1993, decades. We evaluate likely effects of regional Holt 1996, Holt and Golmukiewicz 1996, topography on changes in predicted distribu- Peterson et al. 1999, Rice et al. 2003, Martı´- tional area, geographic position of distribu- nez-Meyer et al. 2004), these ecological char- tions, and fragmentation of species’ ranges. acteristics likely present long-term stable con- straints on the geographic potential of species METHODS (Peterson 2003). As such, we make the pro- Our approach to modeling future geographic visional assumption in this analysis that evolu- distributions of manakin species consisted of tion in ecological characteristics will be nil, and two steps: (1) modeling ecological niches based focus on anticipating spatial shifts in the on known occurrences and datasets summariz- position of appropriate conditions for species. ing present-day environmental features (climate Ecological niche models can be based on and topography), and (2) projecting models present-day distributions with respect to envi- onto environmental datasets summarizing cli- ronmental conditions (Sobero´n and Peterson mates predicted for future time periods (here, 2005). Once models are built and validated in mid-21st century). The general methodology for present-day conditions, their rule sets can be modeling ecological niches and projecting projected onto scenarios of change for antici- effects of climate change on distributions is pating potential distributional shifts and con- described in detail in Peterson et al. (2001). sequent changes in diversity (Pounds et al. 1999, Peterson et al. 2001, 2004, Root et al. 2003, INPUT DATA Roura-Pascual et al. 2005). Although many Creation of an ecological niche model for pro- studies modeling effects of climate change on jection across scenarios of change requires potential species distributions have shown information on the occurrence of species of idiosyncratic and individualistic aspects of the interest in the present day, digital raster GIS likely responses of different species (Perry et al. coverages summarizing climates for both time 1990, Johnston and Schmitz 1997, Kadmon and periods, and digital raster GIS coverages sum- Heller 1998, Price 2000, Peterson et al. 2001), marizing constant features of the landscape (e.g., some generalities are now emerging. For topographic features, soil type). Occurrence example, Peterson et al. (2001, 2002) and information, in the form of unique geographic Peterson (2003) showed that species in flatlands localities at which specimens of a particular regions experienced higher predicted distribu- species have been collected, was accumulated tional shifts and loss in habitable area than from data associated with natural history species in montane areas. Studies examining museum specimens for all manakin species and sufficient numbers of species to permit testing 10 species in closely related families (genera these predictions, however, are quite scarce. Neopelma, Neopipo, Piprites, and Tyranneutes). The manakins (Aves: Pipridae) are a diverse Specimen records were supplemented with data clade of small frugivorous birds distributed from the literature and field observations; across the Neotropics. The family includes complete lists of sources are available on request about 45 species and is broadly distributed in from the senior author. Sample sizes for eight Neotropical forests, inhabiting lowland rain species (five manakins and three from other 780 MARINA ANCIA˜ ES AND A. TOWNSEND PETERSON families) were insufficient for generating models; interpolation of expected changes in each these species were omitted from analysis. climatic layer under each scenario. Although We used seven electronic map layers summa- the scenarios are the same for both circulation rizing aspects of topography (slope, aspect, and models, implementing simulations under con- topographic index, from the U.S. Geological trasting assumptions regarding emissions of Survey’s Hydro 1k elevation derivation data- greenhouse