Responses of water mite assemblages (Acari) to environmental parameters at irrigated rice cultivation fields and native lakes

ABSTRACT Many studies have revealed that water mite communities can be affected by the physical and chemical parameters of the water. The similarity between the water ‘mite assemblages in local water bodies and in irrigated rice areas can be a way to measure the water conditions, enabling an assessment of the anthropic impact in the environment. The aim of this study was to evaluate the distribution of water mites in lakes and irrigated rice fields in south Brazil. To accomplish that we characterized the distinctive environments using physical and chemical variables such as pH, turbidity (NTU), water temperature (°C) and dissolved oxygen (mg/L), in order to verify the influence of these abiotic factors on the species composition of water mite communities; and to compare water mite abundance, richness and composition among different habitats. We assessed three native lakes and four sites with irrigated rice cultivation. Our results showed, for the first time in Brazil, strong correlations between the water mite fauna and turbidity. In addition, native lakes were richer and had greater mite abundance when compared with the irrigated rice areas.

摘要 诸多研究表明，水螨（water mite）群落会受到水体理化参数的影响。本地水体与灌溉稻田中的水螨集合群落之间的相似性，可作为评估水体状况的手段，进而实现对环境中人为影响的评价。本研究旨在探究巴西南部地区湖泊与灌溉稻田内水螨的分布情况。为此，本研究通过pH、浊度（NTU）、水温（℃）及溶解氧（mg/L）等理化指标对两类特色生境进行表征，以明确这些非生物因子对水螨群落物种组成的影响；同时对比不同生境下水螨的丰度、物种丰富度及群落组成。本研究共调查了3个原生湖泊与4处灌溉稻田样点。本研究结果在巴西尚属首次揭示了水螨类群与浊度之间存在显著相关性。此外，相较于灌溉稻田区域，原生湖泊的水螨物种丰富度更高、丰度更大。