Agricultural land use and black fly (Diptera, Simuliidae) species richness and species assemblages in tropical streams, Northeastern Thailand

Abstract

Habitat degradation through agricultural land use is the major factor threatening lotic ecosystems. Although black flies are major components of these ecosystems, the impact of agricultural land use on species diversity and species assemblages has been largely ignored in tropical streams of the Oriental region. The objectives of this study are to examine patterns of species distribution and species richness and to compare black fly species richness and species assemblages in forest and agricultural streams in Thailand. A total of 143 collections were made from 70 stream sites between June 2007 and May 2008. Whereas 19 black fly species found in these collections were all found in forest sites, only 13 species were found in agricultural sites. High species richness was associated with larger, faster, and cooler streams with larger streambed particles and the presence of riparian trees. Logistic regression analyses revealed that stream size, velocity, and riparian vegetation are among the most important factors determining patterns of spatial distribution. The results are largely consistent with studies in other zoogeographic regions, suggesting the existence of general rules for black fly species distributions. Comparisons of the physicochemical conditions between forest and agricultural streams indicated that streams in agricultural areas are warmer, with higher conductivity and fewer riparian trees. Species richness was significantly higher in forest than in agricultural streams (t = 3.61, P \ 0.001). Streams in forest areas were predominantly occupied by S. siamense (73%) but other species were also found at a relatively high frequency ([20%) of the sampling sites. In contrast, streams in agricultural areas were predominantly occupied by S. aureohirtum ([80%) among the sole black fly species at 27% of the sites. The results indicate that agricultural land use has a significantly detrimental impact on black fly diversity and species assemblages.

DNA barcoding as an aid for species identification in austral black flies (Insecta: Diptera: Simuliidae)

“…Day et al, 2008;Kúdela et al, 2014;Ilmonen et al, 2009), and the Oriental Region (e.g. Pramual and Adler, 2014;Pramual and Kuvangkadilok, 2009;Pramual et al, 2011). It has also been demonstrated that the COI barcoding region is a useful tool in revealing levels of genetic diversity in poorly known taxa, for example C. dissimilis, G.…”

“…Simuliid larvae consume dissolved organic matter in the water making it subsequently available to the food chain (Currie and Adler 2008;Malmquivist et al 2001Malmquivist et al 2004, and they are also an important food source for fishes and invertebrates (Currie and Adler 2008). In addition, black flies are important as indicators of freshwater contamination and stream degradation, because their immature stages are susceptible to both organic and inorganic pollution (e.g., Feld et al 2002;Pramual and Kuvangkadilok 2009 …”

Are sugarcane leaf-detritus well colonized by aquatic macroinvertebrates?

“…of allochthonous matter and, consequently, the communities and functional processes in lotic systems (Graça, 2001;Corbi and Trivinho-Strixino, 2008;Beltrão et al 2009;Casatti et al 2009;Pramual andKuvangkadilok, 2009, Zhang et al, 2010).…”

Effects of land use on black fly assemblages (Diptera: Simuliidae) in submontane rivers (West Carpathians, Slovakia)

“…Habitat degradation as a result of anthropogenic disturbance is a major impact threatening biodiversity worldwide (Pramual & Kuvangkadilok 2009); these authors examined black fly species richness and species assemblages in forest and agricultural streams in Thailand. Comparisons of the physicochemical conditions between forest and agricultural streams indicated that streams in agricultural areas are warmer with higher conductivity and fewer riparian trees.…”