P-46
Fish Species Assemblage in the High Elevation First and Second Order Neotropical Streams of the Las Cruces Biological Station, Costa Rica
Fish Species Assemblage in the High Elevation First and Second Order Neotropical Streams of the Las Cruces Biological Station, Costa Rica
Monday, August 18, 2014
Exhibit Hall 400AB (Centre des congrès de Québec // Québec City Convention Centre)
Given current and projected anthropogenic changes in Neotropical landscapes, it is important to collect accurate records of species distributions. Fish assemblages in Neotropical premontane streams are seldom surveyed and may be particularly vunerable to landscape-level changes due to dispersal limitations. Therefore, we conducted a fish survey in a premontane drainage basin during July 2013.
Fish were sampled from three habitat-types (i.e., pools, riffles, and backwater areas) within three streams of the Río Java drainage basin in southwestern Costa Rica. All habitat types were surveyed by seining in a three-step depletion. Collected fish were identified to species, and standard lengths of each individual were recorded.
Four species of fish were collected: Brachyrhaphis terrabensis, Bryconamericus terrabensis, Rhamdia laticauda, and Trichomycterus striatus. Bry. terrabensis and T. striatus were discovered 110 meters above previously established elevational maxiumums. Standard length of Bry. terrabensis decreased as elevation increased (P=0.0009).
These results suggest that there has been a significant change in fish assemblages in the streams of Las Cruces over the past 10 years. While a variety of factors could drive these changes (e.g. mean annual increase in temperature), longer-term population monitoring must occur to determine the causes of this shift in species composition.
Fish were sampled from three habitat-types (i.e., pools, riffles, and backwater areas) within three streams of the Río Java drainage basin in southwestern Costa Rica. All habitat types were surveyed by seining in a three-step depletion. Collected fish were identified to species, and standard lengths of each individual were recorded.
Four species of fish were collected: Brachyrhaphis terrabensis, Bryconamericus terrabensis, Rhamdia laticauda, and Trichomycterus striatus. Bry. terrabensis and T. striatus were discovered 110 meters above previously established elevational maxiumums. Standard length of Bry. terrabensis decreased as elevation increased (P=0.0009).
These results suggest that there has been a significant change in fish assemblages in the streams of Las Cruces over the past 10 years. While a variety of factors could drive these changes (e.g. mean annual increase in temperature), longer-term population monitoring must occur to determine the causes of this shift in species composition.