Diversity of Benthic Biofilms Along a Land Use Gradient in Tropical Headwater Streams, Puerto Rico

TitleDiversity of Benthic Biofilms Along a Land Use Gradient in Tropical Headwater Streams, Puerto Rico
Publication TypeJournal Article
Year of Publication2014
AuthorsBurgos-Caraballo, S, Cantrell, SA, Ramírez, A
JournalMicrobial Ecology
Volume68
Issue1
Pagination47-59
Date Published2014/07/01
ISBN Number0095-3628
Accession NumberLUQ.1174
Other Numbers1174
Keywordsakaike weight, benthic bacterium, benthic biofilm, benthic microbial community, diversity index, interspecific competition, land cover, nitrate concentration, nms analysis, no3 concentration, pielous evenness index, species richness, stream water, urban land, urban stream
Abstract

The properties of freshwater ecosystems can be altered, directly or indirectly, by different land uses (e.g., urbanization and agriculture). Streams heavily influenced by high nutrient concentrations associated with agriculture or urbanization may present conditions that can be intolerable for many aquatic species such as macroinvertebrates and fishes. However, information with respect to how benthic microbial communities may respond to changes in stream ecosystem properties in relation to agricultural or urban land uses is limited, in particular for tropical ecosystems. In this study, diversity of benthic biofilms was evaluated in 16 streams along a gradient of land use at the Turabo watershed in Puerto Rico using terminal restriction fragment length polymorphism. Diversity indices and community structure descriptors (species richness, Shannon diversity, dominance and evenness) were calculated for both bacteria and eukaryotes for each stream. Diversity of both groups, bacteria and eukaryotes, did not show a consistent pattern with land use, since it could be high or low at streams dominated by different land uses. This suggests that diversity of biofilms may be more related to site-specific conditions rather than watershed scale factors. To assess this contention, the relationship between biofilm diversity and reach-scale parameters (i.e., nutrient concentrations, canopy cover, conductivity, and dissolved oxygen) was determined using the Akaike Information Criterion (AICc) for small sample size. Results indicated that nitrate was the variable that best explained variations in biofilm diversity. Since nitrate concentrations tend to increase with urban land use, our results suggest that urbanization may indeed increase microbial diversity indirectly by increasing nutrients in stream water.

URLhttp://link.springer.com/article/10.1007%2Fs00248-014-0401-x
DOI10.1007/s00248-014-0401-x
Short TitleDiversity of Benthic Biofilms Along a Land Use Gradient in Tropical Headwater Streams, Puerto Rico