Abstract

REYES-MALDONADO, Roberto; SANCHEZ-RUIZ, José A.; RAMIREZ, Alonso  and  KELLY, Sean P.. Riparian spider communities as indicators of stream ecosystem condition in the Río Piedras watershed of Puerto Rico. Actu Biol [online]. 2017, vol.39, n.107, pp.58-65. ISSN 0304-3584.  https://doi.org/10.17533/udea.acbi.v39n107a07.

Human degradation of stream ecosystems has led to the creation of a number of methods to assess the severity of such anthropogenic impacts. Biomonitoring protocols that utilize aquatic organisms, in particular macroinvertebrates, are used worldwide as a way to evaluate stream ecosystems. Despite the various benefits these methods provide, they only take into account the stream channel, ignoring altogether the condition of the riparian zone. Other methods look at physical characteristics of both the riparian area and the stream, but ignore biota. Riparian consumers such as spiders have been proposed as potential bioindicators because they could provide a more holistic alternative for assessing stream impairment. Our aim was to determine whether changes in riparian spider communities could be used as indicators to separate sites with different levels of impact along an urban gradient. We conducted correlation analyses of riparian spider community metrics (abundance and species richness) and the percent of vegetation cover in subwatersheds with varying levels of urbanization, along with three other popular stream monitoring protocols. We found a clear difference in spider community composition among subwatersheds, with an overall trend for lower richness and abundances in more impacted sites. Spider abundance correlated significantly with percent vegetation coverage and spider family richness correlated significantly with two widely employed stream monitoring protocols. These findings support the utility of riparian spider communities as indicators for disturbances of stream ecosystems in Puerto Rico and should be incorporated into future biomonitoring protocols to ensure a more holistic view of the condition of stream ecosystems.

Keywords : aquatic macroinvertebrates; Araneae; bioindicators; biomonitoring; tropical urban streams.

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