Introduction
Lake ecosystem is a typical spatial heterogeneous ecosystem formed by
the interaction between lake biological community and the lake
environment. The dynamic process can be shown by the four-dimensional
changes of its biological and environmental elements(Protasov, 2008;
Ward, 1989). If a lake is in a state of natural evolution and
undisturbed by human beings possess a reasonable structure and perfect
function, the lake is in a healthy state (Beck & Hatch, 2009; Cooke,
Welch, Peterson, & Nichols, 2016). Because of the increase in human
population, the speedy development of industrial production and domestic
life, the human demand for water resources has been increasing in the
recent decades. The problems such as the over-exploitation of water
resources, the pollution of water ecological environment have become
increasingly prominent. The structure and function of lake ecosystem had
been seriously destroyed, and the health of lake ecosystems is gradually
deteriorating (Likens, 2010; Tilzer & Serruya, 2012).
As important groups of lake ecosystems, macroinvertebrates play an
important role in lakes, altering the geochemical condition of
sediments, promoting nutrient cycling and facilitating the transfer of
energy among food webs (Cai, Gong, & Qin, 2012; Odountan, de Bisthoven,
Abou, & Eggermont, 2019; Vaughn & Hakenkamp, 2001). Macroinvertebrates
are also commonly used as indicators of aquatic ecosystem integrity
because of their wide range of sensitivity to pollution and relative
longevity (Du et al., 2021; Richman & Somers, 2010; Selvanayagam &
Abril, 2016).
The distribution of macroinvertebrate communities in aquatic systems is
mainly affected by both natural factors and human activities (Z. Yu et
al., 2020). The natural factors mainly include water temperature, water
depth, dissolved oxygen, pH and spatial heterogeneity of habitats
(Bazzanti, Della Bella, & Grezzi, 2009; Free et al., 2009; Shostell &
Williams, 2007). Human activities such as agricultural production
indirectly affect the community structure of macroinvertebrates by
altering the nutrient level of within-lake water bodies (Wijesiri,
Deilami, & Goonetilleke, 2018).
Previous studies have showed that there is a strong correlation between
macroinvertebrate community and environmental factors especially in
streams and rivers (Kłonowska-Olejnik & Skalski, 2014; S. Li et al.,
2018; Zhang, Yang, Wan, Wang, & Wang, 2021). However, little is known
about macroinvertebrate assemblages and the environmental factors
regulating their dynamics in lakes (Jiang et al., 2020; Song et al.,
2007; White & Irvine, 2003). Thus, analyzing the response relationship
between macroinvertebrates and environmental factors has important
guiding significance for improving lake ecological environment.
Lianhuan Lake which is located in Heilongjiang Province, is the largest
alkaline lake in northern China. Lianhuan Lake was formed by tectonic
slump and it consists of 18 small lakes around (Wen-hua, 2012). As an
important lake in northern China, Lianhuan Lake plays an important role
in climate regulation, replenishing groundwater, supporting biodiversity
habitat and economic resource development (Lianjiang & Shulan, 2011; Ma
et al., 2018). However, in the recent years, with the agricultural
reclaimed area in the lake catchment and tourism activities within the
lake, the biodiversity loss and degradation of habitat and other
problems have been more seriously (Jing, Shuying, Yanshan, Haifeng, &
Deqing, 2009; Sun, Zang, Xiao, & Sun, 2010). At present, most of the
studies which have been conducted in Lianhuan Lake are about assessment
of heavy metals and nutrient elements in core sediments (Haifeng et al.,
2010; Sun et al., 2010).
In this study, the community composition of macroinvertebrate
assemblages and their relationships with environmental variables in 13
small lakes within Linhuan Lake was investigated. The 13 small lakes
were chosen because they belong to the same watershed but differ in
natural condition (e.g., lake morphology and environmental
characteristics) which could result in different relationships between
macroinvertebrate assemblages and environment factors. The aims of the
study were as follows: (a) To determine the spatial and temporal
patterns of the macroinvertebrate communities and the community groups,
(b) To identify the indicator taxa’s characterizing of each community
group, and (c) To determine the important environmental variables
shaping the community structure of macroinvertebrates in Lianhuan Lake.
We expected that within-lake environmental variables would explain
substantial amounts of variation in macroinvertebrates, so as to provide
a scientific basis for protecting the health and biodiversity of the
ecosystem in Lianhuan Lake.