Stream sediment bacterial communities exhibit temporally-consistent and distinct thresholds to land use change in a mixed-use watershed

Abstract

Freshwater ecosystems are susceptible to biodiversity losses due to land conversion. This is particularly true for the conversion of land from forests for agriculture and urban development. Freshwater sediments harbor microorganisms that provide vital ecosystem services. In dynamic habitats like freshwater sediments, microbial communities can be shaped by many processes, although the relative contributions of environmental factors to microbial community dynamics remain unclear. Given the future projected increase in land use change, it is important to ascertain how associated changes in stream physico-chemistry will influence sediment microbiomes. Here, we characterized stream chemistry and sediment bacterial community composition along a mixed land-use gradient in West Virginia, USA across one growing season. Sediment bacterial community richness was unaffected by increasing anthropogenic land use, though microbial communities were compositionally distinct across sites. Community threshold analysis revealed greater community resilience to agricultural land use than urban land use. Further, predicted metagenomes suggest differences in potential microbial function across changes in land use. The results of this study suggest that low levels of urban land use change can alter sediment bacterial community composition and predicted functional capacity in a mixed-use watershed, which could impact stream ecosystem services in the face of global land use change.

Temporal and spatial variation in bacterial communities on uniform substrates in non‐wadeable rivers

“…During their study, Pingram et al (2020) showed a near‐linear relationship between cotton strips decomposition and gradients of both native vegetation cover (negative relationship) in the catchment and LUS. Multiple studies have demonstrated the influence of the surrounding landscape on stream bacterial community composition (Martin et al, 2020; Simonin et al, 2019) and have identified taxa that are abundant in streams impacted by urban and agricultural inputs (Laperriere et al, 2020). The indicator taxa in EHC‐D were also associated with increased temperature, possibly linked with less forested riparian margins, increased light, and warmer surface run‐off.…”

Tracking Sources and Dissemination of Indicator Antibiotic Resistance Genes at a Watershed Scale

“…30,32 Previous research also demonstrated that in-stream physiochemistry such as pH is correlated with E. coli concentrations and that chloride concentrations, likely resulting from road salts, are negatively correlated with E. coli. 30 Further, in-stream sediment microbial communities 33 and their correlation with land-use patterns have also been reported. 34 However, the impact of biotic factors (multiple fecal sources) and abiotic factors (landuse and in-stream physiochemical parameters) on the occurrence and persistence of ARGs has never been examined.…”

“…coli . Further, in-stream sediment microbial communities and their correlation with land-use patterns have also been reported . However, the impact of biotic factors (multiple fecal sources) and abiotic factors (land-use and in-stream physiochemical parameters) on the occurrence and persistence of ARGs has never been examined.…”

Land use influences stream bacterial communities in lowland tropical watersheds

“…Freshwater streams receive water from the adjacent land, making them especially vulnerable to the impacts of land-cover change, such as conversion of tropical forest to cattle pasture. Studies have shown that a range of stream properties can vary with a changing landscape, including water temperature, total dissolved solids, and water flow paths 10 – 12 . Further questions regard the extent to which stream microbial community diversity and structure is maintained or can recover as forests are allowed to regenerate on surrounding land and the tradeoffs made when managing land for livelihoods and other ecosystem services.…”