Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields

Abstract

The objective of this study was to verify the richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides of the rice paddy fields. In the crop seasons of 2012/13 and 2013/14, field experiments were performed, which consisted of single-dose applications of the fungicides trifloxystrobin + tebuconazole and tricyclazole, and the insecticides lambda-cyhalothrin + thiamethoxam and diflubenzuron, in 10 m 2 experimental plots, over rice plants in the R3 stage. Control plots with and without rice plants were maintained in order to simulate a natural environment. Soil samples were collected during rice cultivation for assessment of the macroinvertebrate fauna. Chemical-physical parameters assessed in the experiments included temperature, pH and oxygen dissolved in the water and pesticide persistence in the water and in the soil. The application of a single dose of the pesticides and fungicides in the recommended period does not cause significant negative effects over the richness and density of the macroinvertebrates. Tebuconazole, tricyclazole and thiamethoxam showed high persistence in the irrigation water of rice paddy fields. Thus, the doses and number of applications of these products in crops should be carefully handled in order to avoid contamination of the environment.

Evaluation of ecological risk analysis for benthic macroinvertebrates in paddy fields in the Meriç–Ergene River Basin (Turkish Thrace)

“…As a result of the evaluation of hypothetical ecological risk factors that were identified based on the results of statistical analyses applied to the obtained data, it can be concluded that pesticides (S4) have a strong effect on benthic macroinvertebrates in paddy fields in the Meriç-Ergene Basin (Table 12), followed by the effects of heavy metals and nutrients, while the remaining physicochemical parameters can be interpreted as having the least effect (Table 12). The literature reports that species diversity is higher in organically farmed paddy fields where pesticides are not used (Kim et al 2009;Rizo-Patron et al 2013;Namwong et al 2013;Prasetyo et al 2016;Wandscheer et al 2017). Extending the hypothetical risk analysis further, the water quality and accumulation status of each risk factor and the degree of impact on aquatic birds and fish that feed on invertebrates can be assessed.…”

“…The effects of the pressure factors on organisms were scored on a relative scale of 0 to 3 to create the hypothesis effect matrix (0 -no effect; 1 -slight effect; 2 -considerable effect; 3 -severe effect; Table 4). Scoring was based on data available in the literature, including previous studies on the effect of these pressure elements on benthic macroinvertebrates (Kim et al 2009;Rizo-Patron et al 2013;Namwong et al 2013;Prasetyo et al 2016;Wandscheer et al 2017). The results were evaluated by replacing the data in the formula (Harris et al 1994):…”

Estructura De La Comunidad De Dípteros Acuáticos en Tramos De Los Cursos Altos De Los Ríos Fucha Y Bogotá

“…Teniendo en cuenta solamente el índice de Shannon, los puntos altos de los dos ríos, en los que la vegetación ribereña es abundante, tuvieron una calidad del agua moderada, aun estando en zonas protegidas. Al parecer, la función filtradora y retenedora de la vegetación riparia en estos tramos no impide los aportes de nutrientes y materia orgánica producida por otros organismos acuáticos y terrestres (Wandscheer et al, 2017;Da Silva et al, 2019).…”

Species richness and diversity of aquatic insects inhabiting rice fields in Bogor, West Java, Indonesia

“…Chironomus is an important component that connects different trophic levels and plays an important role in the recycling of organic matter. Chironomus spp has been reported as a dominant larval chironomid genus in rice fields in various states/countries e.g., in California (Hesler et al 1993), Mexico (Mercer et al 2016), and Brazil (Wandscheer et al 2017). A significant abundance of Chironomidae is associated with the fact that such insects are considered resistant to the environmental conditions of oxygen depletion and disturbances associated with rice crop management (Molozzi et al 2007).…”

“…A significant abundance of Chironomidae is associated with the fact that such insects are considered resistant to the environmental conditions of oxygen depletion and disturbances associated with rice crop management (Molozzi et al 2007). Moreover, they are detritivores that feed on organic matter deposited in the sediment, which favors their adaptation to several environments (Wandscheer et al 2017).…”