Forested Riparian Buffers as Climate Adaptation Tools for Management of Riverine Flow and Thermal Regimes: A Case Study in the Meramec River Basin

Abstract

Ongoing and projected changes in climate are expected to alter discharge and water temperature in riverine systems, thus resulting in degraded habitat. Climate adaptation management strategies are proposed to serve as buffers to changes in air temperature and precipitation, with these strategies potentially providing relatively stable protection for flow and thermal regimes. Using a hydrologic and water temperature modeling approach in the Meramec River basin in eastern Missouri, U.S.A., we examined the ability of forested riparian buffers to serve as a useful climate adaptation strategy against ongoing and projected changes in climate. We developed a multi-scale approach using Soil and Water Assessment Tool (SWAT) hydrologic and water temperature models as well as a Stream Network Temperature Model (SNTEMP) with different amounts of simulated riparian vegetation to estimate streamflow and water temperature variation within the Meramec River basin under both contemporary and projected future climate conditions. Our results suggest that riparian buffers offer benefits to mitigating increases in water temperature due to shading effects; however, patterns in discharge did not vary substantially based on simulations. From an ecological perspective, the addition of riparian buffers is also projected to reduce the impacts of climate change on Smallmouth Bass (Micropterus dolomieu) by decreasing the number of days water temperatures exceed the thermal tolerance of this species.

Observations of reduced ET and persistent elevated water table beneath a riparian forest gap following emerald ash borer invasion and tree mortality

“…Impacts of persistent canopy gaps in riparian zones following EAB invasion include the loss of annual inputs of high quality ash leaf litter, effects on biogeochemical cycling, and changes in productivity in terrestrial and coupled aquatic systems (Baskerville et al, 2021; Cirmo & McDonnell, 1997; Kreutzweiser et al, 2020; Langenbruch et al, 2012; Larson et al, 2023; Melillo et al, 1982; Neilen et al, 2017; Ricker et al, 2014; Tolkkinen et al, 2020). Loss of shade and a pulse of coarse woody debris as dead ash trees fall in post‐invasion riparian zones will affect wildlife habitat, temperatures, and could potentially alter bacterial communities and invertebrates at the base of terrestrial and aquatic food webs (Burrell et al 2014; Halliday et al, 2016; Knouft et al, 2021; Kolka et al, 2018; Larson et al, 2023; Simmons et al, 2015; Youngquist et al, 2017). This is not a small or isolated issue; ash species are common in many North American forests, and green ash and black ash are frequently dominant species in riparian corridors in the Great Lake States, northeastern U.S., and eastern Canada (Engelken & McCullough, 2020;Kennedy, 1990; Wright & Rauscher, 1990).…”

The effect of temperature on fish swimming and schooling is context dependent

“…Temperature was a significant parameter in most of the models we fit to the data, however temperature explained only a modest percentage of the variance. This dampened response to temperature could be due to the large range of temperatures throughout the year that golden shiners experience in the Missouri region (Jones et al 2011, Knouft et al 2021). Despite this large range in temperature tolerance we still found a significant effect of temperature, suggesting that temperature could have a stronger effect on fish species with tolerance to a smaller range of temperature.…”

Evaluation of Riparian Tree Cover and Shading in the Chauga River Watershed Using LiDAR and Deep Learning Land Cover Classification

“…With improved bank stability, riparian buffers can also reduce sediment flow into rivers during rain events, thereby preventing spikes in turbidity that can harm aquatic life [52,55,56]. In addition, riparian buffers help preserve fish by maintaining food availability and decreasing the number of times water temperatures are greater than what can be tolerated by fish populations such as smallmouth bass and trout [57][58][59]. Riparian buffers can protect against the increased storm surge flooding that will occur with climate change, by reducing the velocity of flowing water and by storing water [5,49].…”