Human activities' fingerprint on multitrophic biodiversity and ecosystem functions across a major river catchment in China

Abstract

Human-induced global change dramatically alters individual aspects of river biodiversity, such as taxonomic, phylogenetic or functional diversity, and is predicted to lead to losses of associated ecosystem functions. Understanding these losses and dependencies are critical to human well-being. Until now, however, most studies

Integration of DNA-Based Approaches in Aquatic Ecological Assessment Using Benthic Macroinvertebrates

“…Since the earliest study published in 2010 [58], there has been a steep growth during the following years in the number of papers published on the theme, with most studies published between 2016 and 2020 (Figure 1). An overview of the studies indicates that metabarcoding-targeting benthic macroinvertebrates have been widely used in ecological assessments in aquatic ecosystems, for example, to assess (1) the effects of contaminants in urbanized, industrialized, and agricultural stream and estuarine areas (e.g., [15,27,39,[58][59][60][61][62][63][64][65]), (2) the effects of stream fragmentation due to dams [66], (3) longterm effects of pesticides [67], oil spills [68], or offshore oil and gas drilling activities [40,69,70], or (4) the effects of invasive species (e.g., invasive algae [71] and crucian carp [72]). It has also proven to be a reliable tool to characterize archive collections of specimens [73], to estimate intraspecific genetic diversity [74], to early detect and monitor invasive species [42,[75][76][77], to be used in the biomonitoring of sea-based fish farms [78,79], and to identify large biogeographic patterns [80,81] and new molecular and cryptic metazoan diversity, in particular in marine ecosystems [55,[81][82][83][84].…”

“…25%, e.g., [42,56,76,77,82,83,96] and fresh; ca. 21%, e.g., [57,64,65,90,92,119]) (Figure 3). The eDNA, which is extracted directly from environmental matrices, such as water and sediment, tend to be made up of a mix of intra-organismal DNA (e.g., from small organisms) and extra-organismal DNA or trace eDNA shed from large organisms (e.g., body parts, secreted mucus, and feces, tissues, and cells) [30,33,34].…”

“…Homogenization of bulk samples with a kitchen blender (e.g., [71,84,88,96,106,114]), an ultra-turrax homogenizer (e.g., [63,112,113]), a fast-prep equipment with MP lysing matrix tubes (MP Biomedicals, Irvine, CA, USA) [24,54], or a mortar and pestle (e.g., [27,65,125]) has been widely employed before DNA extraction, in addition to sediment homogenization (e.g., [38,62,87,110]) (Table S2). These procedures ensure sample homogeneity, which may increase the recovered diversity, in particular of rare or low abundance taxa.…”

“…Regarding sediment preservation for eDNA analysis, most samples have been directly frozen (at −20 • C or −80 • C) (e.g., [38,60,61,94,95,110]), preserved in LifeGuard Soil preservation solution (MoBio, Carlsbad, CA, USA, later acquired by Qiagen, Hilden, Germany) [69,70,78,105], in ethanol at −20 • C [40,43,126], or freeze-dried [62] (Table S2). The filters' material used for water eDNA analysis (i.e., glass microfiber, cellulose nitrate, nylon, polycarbonate, or polyethersulfone), and their pore size (0.2 µm to 5 µm), have been highly variable among studies in both marine and fresh waters (e.g., [36,64,65,70,75,82,96,102,103,127]) (Table S2). Studies comparing the effects of filter material or the pore size on water eDNA recovery are practically absent, but in marine ecosystems, Deiner et al [128] found a significant effect of the filter material (glass microfiber versus cellulose nitrate), but not of the pore size (0.2 µm to 1.2 µm).…”

Analysis of the effectiveness of landscape protection in the Liancheng National Nature Reserve, Gansu, China

“…Natural habitat loss and fragmentation are important threats to global biodiversity conservation (Chase et al 2020;Sala et al 2000). Studies have shown that the establishment of protected areas (PAs) can effectively curb the destruction of natural ecosystems, and this approach is a major component of biodiversity conservation (Li et al 2020;Ma et al 2012;Tang et al 2011). In 2019, there were 261,200 PAs of various types in the world, covering 15.3% of the global terrestrial and freshwater environment (Maxwell et al 2020).…”