Geology topics

Eric Arthur Scholl

Publications and source records attributed to Eric Arthur Scholl.

5 recordsLinked to original sources

USGS2026

Bridging ecology and geosciences in riverscapes: Implications for process-based restoration

There has been a growing interest in integrating geological and ecological processes for sustainable river management and restoration. Lotic systems are shaped by diverse physical processes, including geology, geomorphology, hydrology, and interactions with terrestrial processes. However, restoration practices often prioritize specific habitats or river forms without fully considering the underlying physical processes that support biological communities and ecosystem functions. In this paper, we synthesize studies that integrally examine geological and ecological processes across different scales and components of riverscapes, including geohydrological processes, which have been less investigated in riverscape studies. We begin by examining processes at broader spatial scales, including river–watershed and river–riparian interactions, and gradually narrow our focus to the dynamics that occur among habitats within river channels, through which we highlight the significance of conceptualizing rivers as dynamic “networks” rather than linear features. Finally, we identify both scientific and practical challenges that can be addressed to bridge the gap between basic-science implications and their implementation in riverscape restorations.

Ecological Research↗

USGS2025

Macroinvertebrate community responses to disturbance in a fragmented river with contrasting legacies of alteration

Flow is a critical factor determining the riverine ecosystem structure and function. Widespread hydrologic alteration, however, has impacted the ecological integrity of rivers in ways that are not well understood, including responses of biological communities to increasingly frequent and severe climatic disturbances. Our study compared the responses of invertebrate communities on woody debris to large flooding and extreme drought in two highly contrasting segments of an impaired low-gradient river. The upstream segment, which according to previous research has higher α -diversity and production of large-bodied and sensitive invertebrates, maintained higher flows and longitudinal connectivity throughout the 4-year study. Communities in this upper segment resembled one another among sites (lower spatial turnover) but experienced greater temporal shifts in composition associated with hydrological disturbances. Conversely, invertebrate communities in the highly altered downstream segment, which is impaired by reduced flow, sedimentation, and hypoxia, were composed of smaller-bodied and pollution-tolerant taxa with lower α -diversity. Unlike the upper segment, communities were patchily distributed among sites (higher spatial turnover), which made it more difficult to detect system-wide temporal variation in composition throughout the study. Our study underscores the benefit of including measures of connectivity and spatial heterogeneity when assessing the ecological integrity of lotic systems. Understanding the system-wide response to disturbances across longer time frames can help better predict and mitigate the impacts of climate change on ecosystem integrity in degraded rivers.

River Research and Applications↗

USGS2024

Multiple stressors mediate the effects of warming on leaf decomposition in a large regulated river

Predicting how increasing temperatures interact with other global change drivers to influence the structure and dynamics of Earth's ecosystems is a primary challenge in ecology. Our study made use of multiple simultaneous “natural experiments” to examine how rapid warming, declining nutrients, invasive consumers, and riparian invasive species management interact to influence leaf decomposition in a large and regulated river. Specifically, we compared the breakdown of cottonwood ( Populus fremontii ), willow ( Salix exigua ), and saltcedar ( Tamarix sp.) leaf litter in 2022 to a previous experiment from 1998 that occurred under much cooler water temperatures, and had higher water phosphorus concentrations, low numbers of invasive New Zealand mudsnails ( Potamopyrgus antipodarum ), and unaltered litter chemistry from the herbivory of saltcedar leaf beetles ( Diorhabda carinulata ). We found that the effects of up to 10°C warmer temperatures on leaf decomposition were mediated by the establishment and management of invasive species and declining water nutrient concentrations arising from upstream reservoir lowering. Such interactions led to accelerated breakdown of saltcedar, but relatively minor effects of warming on the rate of cottonwood and willow decomposition. Additionally, our results demonstrate the potential for favorable invasive species management outcomes in the terrestrial environment to produce unintended responses in adjacent freshwater ecosystems. As temperatures continue to rise, it is critical that future studies consider how warming interacts with multiple stressors and environmental factors to influence processes such as decomposition in freshwater ecosystems.

Arizona↗

USGS2024

Rising water temperature in rivers: Ecological impacts and future resilience

Rising water temperatures in rivers due to climate change are already having observable impacts on river ecosystems. Warming water has both direct and indirect impacts on aquatic life, and further aggravates pervasive issues such as eutrophication, pollution, and the spread of disease. Animals can survive higher temperatures through physiological and/or genetic acclimation, behavioral and phenological change, and range shifts to more suitable locations. As such, those animals that are adapted to cool-water regions typically found in high altitudes and latitudes where there are fewer dispersal opportunities are most at risk of future extinction. However, sub-lethal impacts on animal physiology and phenology, body-size, and trophic interactions could have significant population-level effects elsewhere. Rivers are vulnerable to warming because historic management has typically left them exposed to solar radiation through the removal of riparian shade, and hydrologically disconnected longitudinally, laterally, and vertically. The resilience of riverine ecosystems is also limited by anthropogenic simplification of habitats, with implications for the dispersal and resource use of resident organisms. Due to the complex indirect impacts of warming on ecosystems, and the species-specific physiological and behavioral response of organisms to warming, predicting how river ecosystems will change in the future is challenging. Restoring rivers to provide connectivity and heterogeneity of conditions would provide resilience to a range of expected co-occurring pressures, including warming, and should be considered a priority as part of global strategies for climate adaptation and mitigation.

WIREs Water↗

USGS2023

Landscape diversity promotes stable food-web architectures in large rivers

Uncovering relationships between landscape diversity and species interactions is crucial for predicting how ongoing land-use change and homogenization will impact the stability and persistence of communities. However, such connections have rarely been quantified in nature. We coupled high-resolution river sonar imaging with annualized energetic food webs to quantify relationships among habitat diversity, energy flux, and trophic interaction strengths in large-river food-web modules that support the endangered Pallid Sturgeon. Our results demonstrate a clear relationship between habitat diversity and species interaction strengths, with more diverse foraging landscapes containing higher production of prey and a greater proportion of weak and potentially stabilizing interactions. Additionally, rare patches of large and relatively stable river sediments intensified these effects and further reduced interaction strengths by increasing prey diversity. Our findings highlight the importance of landscape characteristics in promoting stabilizing food-web architectures and provide direct relevance for future management of imperilled species in a simplified and rapidly changing world.

Ecology Letters↗