Algal assemblages and their relationship with water quality in tropical Mexican streams with different land uses

Abstract

This study analyzes the relationship between physical and chemical factors and the algal communities in tropical streams in micro-watersheds where [70% of their area has different land uses, specifically, cloud mountain forest, coffee plantations, and livestock pastures. Physical, chemical, and biological variables were measured monthly in each stream over a 1-year period. The concentrations of nitrates ? nitrites, total suspended solids (TSS), and silica in the streams were found to differ during the dry and rainy seasons. Coffee-plantation streams showed the highest levels of suspended solids, nitrates ? nitrites, and sulfates. Based on chlorophyll a concentration, the forest and coffee-plantation streams are oligo-mesotrophic, while pasture streams are meso-eutrophic. Forest streams displayed the lowest levels of richness and algal diversity, followed by coffee-plantation streams, whereas pasture streams were the most diverse. Chlorophyll a concentration and species richness depended on land use and season. Forest coverage was positively correlated with acidophilous and oligo-eutraphentic diatom species. Coffee coverage displayed a significant positive correlation with motile species and a significant negative correlation with pollution-sensitive diatom taxa. The results show that diatom assemblages responded to micro-watershed conditions and can be used to monitor the effects of land use on streams in tropical regions.

Structure of potamoplankton along a gradient of preservation of riparian vegetation in subtropical streams

“…Opposite to that, few variables showed clear patterns, among which stands out the highest concentration of total dissolved solids, temperature and electrical conductivity in points with less vegetation preserved. Similar condition was obtained by other authors (Johnson et al 1997, Carpenter and Waite 2000, Vázquez et al 2011). Regardless of this fact, the highest values of total nitrogen and total phosphorus loads contrary to the riparian vegetation gradient showed the significant impact of the vegetation absence on water quality.…”

“…lineata, Nitzschia amphibia are classified as indicator species of eutrophic environments, while Surirella splendida meso-eutrophic environments and Ulnaria ulna are indifferent to environment trophic status. Closterium moniliferum is regarded as a typical specie of river (Descy et al 2012) and has also been associated to stream ecosystems near pastures (Vázquez et al 2011). The descriptive species of group Euglenophyceae (Euglena sp., Phacus pleuronectes e P. longicauda) are generally found in ecosystems with high organic pollution (Safonova andShaulo 2009, Reynolds et al 2002).…”

“…Several studies have reported on the influence of riparian vegetation on the water quality and on the response of the phytoplankton community (Naiman et al 2005, Dudgeon 2008 on the community of diatoms in tropical and temperate rivers (Vázquez et al 2011, Gabel et al 2012) has been observed, and an increase in the proportion of N and P when compared to silicate (Si), may result in a decline of diatoms (Conley andMalone 1992, Cugier et al 2005). Moreover, changes in the nutrient loadings caused by deforestation of up to 50% of riparian forests may enhance eutrophication and probably increase the frequency of algal blooms (Perry et al 1999).…”

Impacts of Habitat Degradation on Tropical Montane Biodiversity and Ecosystem Services: A Systematic Map for Identifying Future Research Priorities

“…A myriad of habitat degradation effects on biodiversity and ecosystem services in TMFs were reported (Figure 7). Equivocal or inverse responses in species richness may be due to sampling in habitats with intermediate levels of degradation, which often show higher species richness than pristine environments (e.g., Deloya et al, 2007;Vazquez et al, 2011;Mendez-Castro and Rao, 2014;Abella-Medrano et al, 2015;Badillo-Saldana et al, 2016;Gomez-Diaz et al, 2017). The main cause cited was higher resource availability (e.g., food abundance, breeding habitat or light availability) that attract resource-generalist species (Vazquez et al, 2011;Mendez-Castro and Rao, 2014;Abella-Medrano et al, 2015;Badillo-Saldana et al, 2016).…”

“…Equivocal or inverse responses in species richness may be due to sampling in habitats with intermediate levels of degradation, which often show higher species richness than pristine environments (e.g., Deloya et al, 2007;Vazquez et al, 2011;Mendez-Castro and Rao, 2014;Abella-Medrano et al, 2015;Badillo-Saldana et al, 2016;Gomez-Diaz et al, 2017). The main cause cited was higher resource availability (e.g., food abundance, breeding habitat or light availability) that attract resource-generalist species (Vazquez et al, 2011;Mendez-Castro and Rao, 2014;Abella-Medrano et al, 2015;Badillo-Saldana et al, 2016). Changes in species composition across a disturbance gradient were often reported, with resilient species more likely to be generalists (e.g., Pattanavibool and Dearden, 2002;Gove et al, 2013;Diaz-Garcia et al, 2017;Gomez-Diaz et al, 2017), not threatened (Basham et al, 2016), have broad elevational distributions (Escobar and de Ulloa, 2000), introduced (Gomez-Diaz et al, 2017), and adaptable to climatic change (Ariyanti et al, 2008).…”