Land use change causes environmental homogeneity and low beta-diversity in Heteroptera of streams

Abstract

Although species distribution pattern is a widely discussed topic, understanding the mechanisms that drive it in time and space is still one of the central goals of ecology. Moreover, it is of the most importance to discuss the maintenance of this biodiversity and the services it provides. Therefore, our aim is to test the following hypotheses: 1) Preserved environments have higher beta-diversity than environments with lower preservation values, since beta-diversity is determined by environmental variations between habitats; 2) Beta-diversity will be better than species richness to detect changes in community regarding environmental integrity gradients. This will occur because richness is not sensitive to changes in composition and this might mask results when sensitive species are lost and generalist species are introduced into the altered environments. In order to test these hypotheses, 20 points were sampled in five streams of the Brazilian Cerrado with different integrity conditions. Environmental change did not affect Heteroptera richness; however, it affected the beta-diversity of the group as a whole and of Nepomorpha, also negatively affecting both Gerromorpha beta-diversity and richness. Moreover, there was difference in variation of Gerromorpha composition in altered and degraded sites, but there was no effect on Nepomorpha. These results show that Gerromorpha is more sensitive to physical changes in streams caused by the loss of environmental integrity. Therefore, environmental changes with no regard to riparian vegetation boundaries causes shifts in stream conditions and changes aquatic communities, which places at risk the ecosystems services provided by these communities.

Hidden diversity – DNA metabarcoding reveals hyper-diverse benthic invertebrate communities

“…The above studies of stream invertebrate beta diversity patterns are performed at large spatial scales (e.g., comparing beta diversity between major watersheds or geographic regions), and there are few stream studies that explore spatial resolution at small scales (e.g., microhabitat level, but see Costa &Melo, 2008 andHeino et al, 2013). In addition to this, many of these studies are performed at variable taxonomic resolution using morphological identification (a mix of family, genus, and rarely species), focus on specific taxonomic groups (e.g., Heteroptera only; Dias-Silva et al, 2020), or exclude diverse insect groups such as chironomids (e.g, Astorga et al, 2014;Costa & Melo, 2008;Petsch et al, 2021). Next-generation sequencing methods have been extremely effective at revealing incredibly diverse communities of terrestrial invertebrates (D'Souza and Hebert, 2018;Maggia et al, 2021;Steinke et al, 2021aSteinke et al, , 2021b, and it is likely that using molecular identification to explore similar patterns in streams will provide greater insight into both alpha and beta diversity patterns.…”

Dams Change Beta Diversity of Aquatic Communities in the Veredas of the Brazilian Cerrado

“…There are already indications that small dams can change Odonata and Heteroptera assemblages (Brasil et al, 2014a;De Marco et al, 2014) in Cerrado streams. Additionally, Odonata (Carvalho et al, 2013;Calvão et al, 2018) and Heteroptera (Vieira et al, 2015;Dias-Silva et al, 2020) assemblages can be affected by changes in land use when they are embedded in areas used for cattle raising, even in streams without dams. It happens mostly because cattle change the riparian vegetation by trampling on it when they drink water.…”

“…We tested the hypothesis that beta diversity would be negatively affected by environmental changes caused by dam construction. Because both Odonata (Oliveira-Junior and Juen, 2019) and Heteroptera (Dias-Silva et al, 2020) orders harbor taxa sensitivity and taxa are tolerant to environmental change, we expect that dam construction will promote species turnover, where tolerant species will replace sensitive ones.…”

Capítulo 3: Diversidad Biológica y Redes Ecológicas en la Amazonía

“…Varios taxones se consideran bioindicadores acuáticos debido a su dependencia del medio acuático durante al menos alguna etapa de su vida. El mantenimiento de los bosques de ribera previene la pérdida de especies y servicios ecosistémicos proporcionados por las comunidades de insectos acuáticos (Dala'Corte et al 2020, Dias-Silva et al 2020. Al actualizar la lista de Trichoptera, Paprocki y França (2014) encontraron un aumento de más del 65% en el número de especies, de las cuales el 90% fueron especies nuevas para la ciencia, además de nuevos registros para Brasil.…”