Angelo, Courtney , Daehler, Curtis .
Impacts of future climates on fire-promoting invasive grass distributions in the Hawaiian Islands.
Climate warming in the tropics has been documented during the past century. Warming has been predicted to increase invasions in tropical montane environments more so than in temperate montane environments, however, current research has primarily addressed the influence of climate change on plant distributions in temperate ecosystems. Invasive C4 and few C3 grasses are known to change fire-frequencies, alter ecosystem processes and displace native species in the tropics; these species are of particular concern. To predict changes in invasive C4 grass distributions in response to a warming climate in the Hawaiian Islands, climate niche models were developed for four fire-promoting invasive C4 grasses using Maxent. Average minimum temperature during January, annual precipitation, and driest quarter were the environmental variables used to build the models. For future projections, we increased the average minimum temperature for January by 1.35 degrees Celsius based on expected warming trends for the Hawaiian Islands for the year 2050. We found that Urochloa maxima and Schizachyrium condensatum ranges increased in area by 4% and 6%, respectively, while, Melinis minutiflora and Cenchrus ciliaris ranges decreased 7% and less than 1% respectively. Cenchrus ciliaris was primarily limited by rainfall rather than by temperature, thus its distribution was not projected to change with an increase in temperature. Although our study failed to find conclusive evidence for an overall expansion of C4 grasses, we did find that C4 grass distributions are likely to shift with a warming climate. Similar patterns are expected for ecosystems elsewhere in the tropics, where invasion by fire adapted grasses at lower elevations is already well documented.
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1 - University of Hawaii at Manoa, Department of Botany, 3190 Maile Way, St. John Rm 101, Honolulu, HI, 96822, USA
climate niche modeling.
Presentation Type: Oral Paper:Papers for Topics
Location: Lindell A/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 10:45 AM