OOS 2-7
Decapod communities under the effects of hurricanes, droughts and humans in neotropical streams
Tropical and temperate streams differ ecologically in diversity, seasonal variation, and productivity. In contrast to temperate streams, Neotropical streams are frequently dominated by a diverse and very specialized group of decapods that have important roles in recycling nutrients and in processing organic matter in both headwater forested ecosystems and in coastal urban streams. Long-term research on streams of the Luquillo Mountains of Puerto Rico have documented the negative effect of hurricanes, droughts, and people on the species richness and abundance of freshwater decapods. New comparative studies among forested (Luquillo Experimental Forest) and urban (Rio Piedras) watersheds are part of the Luquillo Long Term Ecological Research Program that has previously focused on effects of different types of natural disturbances, human impacts, and Caribbean climate change.
Results/Conclusions
The decapod species were less abundant in upstream pools immediately after hurricanes and species dominance changed after intensive droughts as a result of variations in the water discharge, predation, and changes in the habitat heterogeneity. In urban streams the diversity and abundance of shrimps and crabs were associated with additional stressors that degraded decapod habitat. Nonetheless, although the urban streams had fewer species than the forested streams the urban ecosystems still functioned effectively. Resilient responses by a combination of native and non-native species characteried the urban river. Effects of climatological events, alterations of the environment, and the impact of urban land uses altered the interactions among species resulting in some relatively small changes in the organizational composition of the community and the ecosystem processes.