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Coral Gables, FL, United States

Pemberton R.W.,Fairchild Tropical Botanic Garden
Botanical Review | Year: 2010

Orchid pollinators have highly varied life histories with complex biotic resource requirements, about which we have limited knowledge. Among the specialist orchid pollinators are insect predators and parasitoids with specific prey types such as aphids and subterranean scarab larvae; oligolectic bees that collect pollen from limited sources such as bellflowers; euglossine bees and butterflies that collect particular plant chemicals for reproduction and self defense; oil-collecting bees that provision their brood cells with floral oils from a few plants; bees that collect rare floral resins to construct their nest and brood cells; moths and butterflies that require specific larval host plants; mosquitos and horse flies that need blood; and fungus gnats and carrion flies tied to fungi and dead animals. Loss of critical biotic resources and relationships can reduce the abundance of orchid pollinators and/or their effectiveness. Protection of large, plant rich, pesticide-free orchid habitats is key to conserving essential pollinator resources. © The New York Botanical Garden 2010. Source

Feeley K.J.,Fairchild Tropical Botanic Garden
Global Change Biology | Year: 2012

Species are predicted to respond to global warming through 'cold-ward' shifts in their geographic distributions due to encroachment into newly suitable habitats and/or dieback in areas that become climatically unsuitable. I conduct one of the first-ever tests of this hypothesis for tropical plant species. I test for changes in the thermal distributions of 239 South American tropical plant species using dated herbarium records for specimens collected between 1970 and 2009. Supporting a priori predictions, many species (59%) exhibit some evidence of significant cold-ward range shifts even after correcting for collection biases. Over 1/3 of species (35%) show significant cold-ward movement in their hot thermal limits (mean rate of change = 0.022 °C yr -1). Most of these species (85%; 30% of all study species) show no corresponding shift in their cold thermal limits. These unbalanced changes in the species' thermal range limits may indicate species that are experiencing dieback due to their intolerance of rising temperatures coupled with an inability to expand into newly climatically suitable habitats. On the other hand, 25% of species show significant cold-ward shifts in their cold thermal range limits (mean rate of change = 0.003 °C yr -1), but 80% of these species (20% of all study species) show no corresponding shift in their hot thermal range limits. In these cases, the unbalanced shifts may indicate species that are able to 'benefit' under global warming, at least temporally, by both tolerating rising temperatures and expanding into new suitable habitat. An important ancillary result of this study is that the number of species exhibiting significant range shifts was greatly influenced by shifting collector biases. This highlights the need to account for biases when analyzing natural history records or other long-term records. © 2011 Blackwell Publishing Ltd. Source

Duque A.,National University of Colombia | Stevenson P.R.,University Los Andesbogota Dc | Feeley K.J.,Florida International University | Feeley K.J.,Fairchild Tropical Botanic Garden
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Climate change is expected to cause shifts in the composition of tropical montane forests towards increased relative abundances of species whose ranges were previously centered at lower, hotter elevations. To investigate this process of "thermophilization," we analyzed patterns of compositional change over the last decade using recensus data from a network of 16 adult and juvenile tree plots in the tropical forests of northern Andes Mountains and adjacent lowlands in northwestern Colombia. Analyses show evidence that tree species composition is strongly linked to temperature and that composition is changing directionally through time, potentially in response to climate change and increasing temperatures. Mean rates of thermophilization [thermal migration rate (TMR), °C·y-1] across all censuses were 0.011 °C·y-1 (95% confidence interval = 0.002-0.022 °C·y-1) for adult trees and 0.027 °C·y-1 (95% confidence interval = 0.009-0.050 °C·y-1) for juvenile trees. The fact that thermophilization is occurring in both the adult and juvenile trees and at rates consistent with concurrent warming supports the hypothesis that the observed compositional changes are part of a long-term process, such as global warming, and are not a response to any single episodic event. The observed changes in composition were driven primarily by patterns of tree mortality, indicating that the changes in composition are mostly via range retractions, rather than range shifts or expansions. These results all indicate that tropical forests are being strongly affected by climate change and suggest that many species will be at elevated risk for extinction as warming continues. Source

Feeley K.J.,Wake forest University | Feeley K.J.,Florida International University | Feeley K.J.,Fairchild Tropical Botanic Garden | Silman M.R.,Fairchild Tropical Botanic Garden
Global Change Biology | Year: 2010

Andean plant species are predicted to shift their distributions, or 'migrate,' upslope in response to future warming. The impacts of these shifts on species' population sizes and their abilities to persist in the face of climate change will depend on many factors including the distribution of individuals within species' ranges, the ability of species to migrate and remain at equilibrium with climate, and patterns of human land-use. Human land-use may be especially important in the Andes where anthropogenic activities above tree line may create a hard barrier to upward migrations, imperiling high-elevation Andean biodiversity. In order to better understand how climate change may impact the Andean biodiversity hotspot, we predict the distributional responses of hundreds of plant species to changes in temperature incorporating population density distributions, migration rates, and patterns of human land-use. We show that plant species from high Andean forests may increase their population sizes if able to migrate onto the expansive land areas above current tree line. However, if the pace of climate change exceeds species' abilities to migrate, all species will experience large population losses and consequently may face high risk of extinction. Using intermediate migration rates consistent with those observed for the region, most species are still predicted to experience population declines. Under a business-as-usual land-use scenario, we find that all species will experience large population losses regardless of migration rate. The effect of human land-use is most pronounced for high-elevation species that switch from predicted increases in population sizes to predicted decreases. The overriding influence of land-use on the predicted responses of Andean species to climate change can be viewed as encouraging since there is still time to initiate conservation programs that limit disturbances and/or facilitate the upward migration and persistence of Andean plant species. © 2010 Blackwell Publishing Ltd. Source

Machovina B.,Florida International University | Feeley K.J.,Fairchild Tropical Botanic Garden
Ecological Economics | Year: 2013

Species distribution modeling (SDM) is used to map areas predicted to be suitable for commercial banana production in Central and northwestern South America. Using the downscaled climate projections for 2060 from seven leading global climate models we then predict the geographical shifts in areas suitable for banana production. We repeat this process for conventional and organic banana production. Approximately half of the existing conventional plantations included in the analysis are located in areas predicted to become unsuitable for banana production by 2060. The overall extent of areas suitable for conventional banana cultivation is predicted to decrease by 19%, but all countries are predicted to maintain some suitable areas. The extent of areas suitable for organic banana cultivation is predicted to nearly double due primarily to climatic drying. Several countries (e.g., Colombia and Honduras) are predicted to experience large net decreases in the extent of areas suitable for banana cultivation. Some countries (e.g., Mexico) are predicted to experience large net increases in the extent of suitable areas. The shifts in the location of areas that will be suitable for banana cultivation are predicted to occur mainly within areas outside of protected areas and that are already under agricultural production. © 2013 Elsevier B.V. Source

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