Taxonomic and Numerical Resolutions of Nepomorpha (Insecta: Heteroptera) in Cerrado Streams

Abstract

Transformations of natural landscapes and their biodiversity have become increasingly dramatic and intense, creating a demand for rapid and inexpensive methods to assess and monitor ecosystems, especially the most vulnerable ones, such as aquatic systems. The speed with which surveys can collect, identify, and describe ecological patterns is much slower than that of the loss of biodiversity. Thus, there is a tendency for higher-level taxonomic identification to be used, a practice that is justified by factors such as the cost-benefit ratio, and the lack of taxonomists and reliable information on species distributions and diversity. However, most of these studies do not evaluate the degree of representativeness obtained by different taxonomic resolutions. Given this demand, the present study aims to investigate the congruence between species-level and genus-level data for the infraorder Nepomorpha, based on taxonomic and numerical resolutions. We collected specimens of aquatic Nepomorpha from five streams of first to fourth order of magnitude in the Pindaíba River Basin in the Cerrado of the state of Mato Grosso, Brazil, totaling 20 sites. A principal coordinates analysis (PCoA) applied to the data indicated that species-level and genus-level abundances were relatively similar (>80% similarity), although this similarity was reduced when compared with the presence/absence of genera (R = 0.77). The presence/absence ordinations of species and genera were similar to those recorded for their abundances (R = 0.95 and R = 0.74, respectively). The results indicate that analyses at the genus level may be used instead of species, given a loss of information of 11 to 19%, although congruence is higher when using abundance data instead of presence/absence. This analysis confirms that the use of the genus level data is a safe shortcut for environmental monitoring studies, although this approach must be treated with caution when the objectives include conservation actions, and faunal complementarity and/or inventories.

Is it possible to simplify environmental monitoring? Approaches with zooplankton in a hydroelectric reservoir

“…Similar results were found for different groups (Giehl et al, 2014;Souza et al, 2016;Valente-Neto et al, 2016) including zooplankton (Carneiro et al, 2013). The concordance with higher taxonomic levels can be justified by the low number of species found by genus and family, which creates a higher similarity between the more and less specific data sets (Giehl et al, 2014). This approach is acceptable when there is not a major loss of information between the data sets (high concordance level), thus resulting in lower effort for taxonomic identification of taxa (Carneiro et al, 2010;Heino & Soininen, 2007;Khan, 2006).…”

“…Similar results were found for different groups (Giehl et al, 2014;Souza et al, 2016;Valente-Neto et al, 2016) including zooplankton (Carneiro et al, 2013). The concordance with higher taxonomic levels can be justified by the low number of species found by genus and family, which creates a higher similarity between the more and less specific data sets (Giehl et al, 2014).…”

“…Density (Dens), Mean and Standard Deviation (SD) of the zooplankton species density sampled in reservoir Serra da Mesa-GO (Brazil). (Bessa et al, 2011;Giehl et al, 2014;Heino, 2008;Valente-Neto et al, 2016). However, some studies indicate the use of numerical resolution for zooplanktonic community (Gomes et al, 2015) and other groups (Carneiro et al, 2010;Ribas & Padial, 2015).…”

Ecological studies of mayflies (Insecta, Ephemeroptera): Can sampling effort be reduced without losing essential taxonomic and ecological information?

“…ACTA AMAZONICA of taxonomic groups that have more congeneric species, we suggest that further studies are conducted. The high degree of consistency found in the present study between the species and genus level resolutions was similar to that found by Giehl et al (2014) in insects of the order Heteroptera. These authors concluded that this congruence may be accounted for the small number of species per genus, with more than half the genera being represented by only one or two species, a situation also observed for ephemeropterans in the current study.…”

Neotropical dragonflies (Insecta: Odonata) as indicators of ecological condition of small streams in the eastern Amazon

“…, ; Giehl et al . ). Our HII values varied from 0.28 to 0.96; hence, we classified the 50 streams into three arbitrary environmental condition categories (splitting the range equally into three): degraded (0.28–0.49; 19 sites), altered (0.50–0.75; 19 sites) and preserved (0.76–0.96; 12 sites).…”