Macroinvertebrate functional feeding groups and its relationship with environmental factors in the Jingui River of Shenzhen
Chen Suna, Lixian Xiaa, Min Zhangb, Qianyun Hea, Naiqi Yua, Hongyong Xianga, Haijun Yanga, *
a School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China
b Shenzhen Guanghuiyuan Environmental Water Co. Ltd., Shenzhen 518000, China
Abstract:The differences in the functional diversity and species diversity of macroinvertebrates can be based to evaluate the changes in local environment. However, there are little available analysis on the effect mechanism of seasons on the functional characteristics of macroinvertebrate communities in the subtropical region. This work compared the functional feeding groups (FFG) of macroinvertebrates in wet season, normal season, and dry season of 2021 in Jingui River in Shenzhen. This work mainly was aimed to comprehend the connection between the environmental driving elements in the Jingui River and the seasonal distribution of the FFG of macroinvertebrates. The highest species diversity and abundance were found among the collector-gatherers (GC), while the largest biomass was observed among the predators. Overall, the functional diversity of the Jingui River exhibited a significantly seasonal change. In particular, the functional diversity decreased in wet season, implying a stronger disturbance. A multiple regression analysis revealed that the species diversity and stream environmental parameters might account for 12.8% - 72.9% of the functional diversity of macroinvertebrates.
Keywords: Macroinvertebrate; Functional feeding groups; River ecosystem; Functional diversity
Introduction
The group of macroinvertebrates having the same ecological purpose is called the functional feeding groups (FFG) of macroinvertebrates (Liu et al., 2014). Traditional research on macroinvertebrates focuses more on community structure analysis and *Correspondence:
Corresponding Author: yanghaijun@ynu.edu.cn
species diversity instead of FFG and diversity(Brown et al., 2018). Applying FFG in the research on structure of the macroinvertebrate community helps to evaluate the ecosystem structure and function completely and to simplify the complicated internal relations(Mouton et al., 2020). In this case, differences in FFG of macroinvertebrates can be based to evaluate the mechanism of changes in the local environment(Zhong et al., 2020).
Functional diversity has recently received extensive attention to predict the connections among various ecological processes(Wang et al., 2019). The functional diversity is formed by fundamental variation among the interspecific functional features in clusters and the way those traits react to environmental stresses and interference(Baker et al., 2021). Evaluating the aquatic ecosystems is of high significance due to the variety of its forms and habits, which may respond to the environmental pressures in multiple ways(Ochieng et al., 2019). For examples, Talley used functional categories to examine the connection between macroinvertebrate habitats and communities in California Bay tidal flats(Talley et al., 2000), and Thrush investigated how macroinvertebrates contribute to the intertidal ecology(Thrush et al., 2006). The functional diversity is depended by the ability of biological communities to predict the rapidity and dependability of environmental processes(Mason et al., 2005). As a combination of many environmental factors, riverbed structure influences the community structure and functional diversity of macroinvertebrates directly or indirectly(Zhu et al., 2020). Meanwhile, the functional diversity displays greatly different functional features and can indicate how those traits react to environmental interference(Zhong et al., 2020). FFG and functional diversity indices demonstrate the responses to environmental stressors and reflect the changes in community organization(Li et al., 2022). In addition, functional diversity is generally handled by unique categories in the river benthic ecosystems(Wang et al., 2019). The environmental status depends on the biological traits that show how to respond to pressure from the external environment(Lavorel et al., 1997). Mason believed that the functional variety can’t be effectively represented by a single index(Mason et al., 2005). Electing correct indexes is the essential for creating a functional diversity biological assessment system(Jiang et al., 2021). Villeger presented three multidimensional indices of consecutive function features to investigate the three distinct aspects of the functional diversity(Villeger et al., 2008). Currently, the river benthic habitats are rarely mentioned, and the functional diversity indices are primarily selected to investigate the terrestrial plant ecosystems(Chen et al., 2018; Liu et al., 2019).
The Jingui River is the secondary tributary of the Pingshan River, which is included in the Dongjiang River system. The Jingui River Basin accounts for roughly 50% of the area of the Chi’ao Reservoir and is the primary source of the reservoir. The ecological environment of the Jingui River has been somewhat put in danger by year-round sediment deposition, mountain torrents, and haphazard human activity. The Shenzhen Municipal Bureau of Planning and Natural Resources, therefore, started a comprehensive renovation for the limited watershed of the Jingui River in September 2020, which primarily consisted of flood control and ecological restoration. This work evaluated the biological characteristics and FFGs of the macroinvertebrates in the Jingui River, and analyzed the connection between species diversity and functional diversity. Results in this work may offer some useful information for assessing the community structure and ecosystem stability of the macroinvertebrates.
Materials and methods
Study area and macroinvertebrate sampling
The Jingui River was situated in the Pingshan New District of Shenzhen, Guangdong Province, China (Fig. 1). The Pingshan River Basin is affected by a subtropical marine monsoon climate, and the average annual temperature and precipitation are 22°C and 1,984 mm, respectively. The river originates on the southern slope of Tianxin Mountain and flows from southeast to northwest before accessing the Chi’ao Reservoir.
Macroinvertebrates in the Jingui River were sampled in July (wet season), October (normal season), and December (dry season) in 2021 using a Surber sampler (30 × 30 cm, 500 μm mesh) from three quantitative replicates. The samples covered the most representative macroinvertebrate microhabitats of each site. The sampled macroinvertebrates were preserved in 75% ethanol and then recognized and categorized in the laboratory with a stereo microscope (Olympus SZX7). The FFGs were employed to further classify the macroinvertebrates into shredder (SH), collector-filterer (FC), collector-gatherer (GC), scraper (SC) and predator (PR)(Lin et al., 2022).