Tropical Streams
Tropical streams are generally considered heterotrophic systems that rely heavily on external inputs from the surrounding vegetation as the primary energy source. Despite receiving large amounts of this resource, consumer communities in many tropical headwaters are not consistent with predictions for detritus-based stream systems (e.g., shredders are not well represented). Recent evidence suggests that consumer communities in tropical headwaters may use internal sources of energy more than originally thought, particularly after disturbance events that increase light penetration and reduce storage of leaf litter through scouring. Much of our knowledge of tropical streams and their communities is based on short-term studies that generally focus on consumer diversity and abundance estimates and thus comprehensive investigations linking consumers to ecosystem processes are generally lacking. Consumers play an
important role in the functioning of ecosystems and can influence processes such as nutrient cycling, decomposition, and energy flow. In light of declining biodiversity, understanding the roles of consumers in ecosystems has become a central theme in ecological research.
important role in the functioning of ecosystems and can influence processes such as nutrient cycling, decomposition, and energy flow. In light of declining biodiversity, understanding the roles of consumers in ecosystems has become a central theme in ecological research.
Southeastern Coastal Plain Rivers and Wetlands
The ecological attributes of rivers and wetlands are highly diverse and provide important ecosystem services. Nonetheless, these habitats continue to face increasing threats from a rapidly growing human population, consequent land use changes, and habitat alterations (Brinson and Malvarez 2002, Dudgeon et al. 2006). Furthermore, the consequences of climate change will undoubtedly impact the status of freshwater ecosystems globally. Although assessment methods that target the physicochemical and biological components that help shape aquatic communities continue to be developed, modified, or improved, these rarely incorporate assessment tools that integrate both structural and functional metrics to evaluate ecosystem condition. In addition, the vast majority of assessments on the potential effects of a changing climate on freshwater ecosystems don’t often incorporate these changes in a natural setting or at larger levels of organization (ecosystem scale). Continued efforts at the national level are needed to establish a reference for the response of freshwater ecosystems to climate change scenarios at larger spatial and temporal scales. These efforts can also benefit from the inclusion of datasets generated from the development of complimentary programs that focus on particular freshwater ecosystems at regional scales. In the Southeastern Coastal Plain, blackwater rivers and inland wetlands are important targets to assess the effects of natural and anthropogenic disturbances as they are often understudied systems that can harvest high levels of diversity and productivity. They are also known to be important habitats for organic matter processing, decomposition and other ecosystem services (e.g., nutrient cycling, carbon sequestration) (Meyer 1990; Meyer et al. 1999). Despite their ecological importance, freshwater ecosystems in this region are continuously threatened by increased human demand for the resource.