Geology topics

Brett B. Roper

Publications and source records attributed to Brett B. Roper.

7 recordsLinked to original sources

USGS2025

The effects of unpaved roads on instream sediment: Patterns and challenges for monitoring

Despite > 700,000 km of unpaved roads in the western United States, our knowledge of how roads impact instream sediment is unclear. We combined two studies, including (1) a regional analysis linking stream habitat data from a large-scale monitoring program with road density data to identify generalizable relationships between roads and streambed sediment distributions and (2) a targeted field study to evaluate the responses of streambed and suspended sediment collected at locations above and below road–stream connection points to better understand the consistency of responses. Regional analyses indicated a significant positive relationship between road density and fine sediment in pool tails and a significant negative relationship between road density and median particle size. We also found significant relationships between landscape, climate, and local covariates and streambed sediment metrics, where most of the parameter estimates of the covariates were equal to or stronger than those for road density. Field studies suggested higher suspended sediment levels across the seasonal hydrologic regime where roads were open to travel year-round. However, sediment responses to road–stream connection points varied by metric and site. Together, our results indicated negative relationships between increasing road densities and sediment size distributions, but detecting road effects at site scales will be challenging given the effects of covariates that can overwhelm sediment signals.

Montana↗

USGS2023

Sharing FAIR monitoring program data improves discoverability and reuse

Data resulting from environmental monitoring programs are valuable assets for natural resource managers, decision-makers, and researchers. These data are often collected to inform specific reporting needs or decisions with a specific timeframe. While program-oriented data and related publications are effective for meeting program goals, sharing well-documented data and metadata allows users to research aspects outside initial program intentions. As part of an effort to integrate data from four long-term large-scale US aquatic monitoring programs, we evaluated the original datasets against the FAIR (Findable, Accessible, Interoperable, Reusable) data principles and offer recommendations and lessons learned. Differences in data governance across these programs resulted in considerable effort to access and reuse the original datasets. Requirements, guidance, and resources available to support data publishing and documentation are inconsistent across agencies and monitoring programs, resulting in various data formats and storage locations that are not easily found, accessed, or reused. Making monitoring data FAIR will reduce barriers to data discovery and reuse. Programs are continuously striving to improve data management, data products, and metadata; however, provision of related tools, consistent guidelines and standards, and more resources to do this work is needed. Given the value of these data and the significant effort required to access and reuse them, actions and steps intended on improving data documentation and accessibility are described.

Enviornmental Monitoring and Assessment↗

USGS2017

The NorWeST summer stream temperature model and scenarios for the western U.S.: A crowd-sourced database and new geospatial tools foster a user-community and predict broad climate warming of rivers and streams

Thermal regimes are fundamental determinants of aquatic ecosystems, which makes description and prediction of temperatures critical during a period of rapid global change. The advent of inexpensive temperature sensors dramatically increased monitoring in recent decades, and although most monitoring is done by individuals for agency‐specific purposes, collectively these efforts constitute a massive distributed sensing array that generates an untapped wealth of data. Using the framework provided by the National Hydrography Dataset, we organized temperature records from dozens of agencies in the western U.S. to create the NorWeST database that hosts >220,000,000 temperature recordings from >22,700 stream and river sites. Spatial‐stream‐network models were fit to a subset of those data that described mean August water temperatures (AugTw) during 63,641 monitoring site‐years to develop accurate temperature models ( r 2 = 0.91; RMSPE = 1.10°C; MAPE = 0.72°C), assess covariate effects, and make predictions at 1 km intervals to create summer climate scenarios. AugTw averaged 14.2°C (SD = 4.0°C) during the baseline period of 1993–2011 in 343,000 km of western perennial streams but trend reconstructions also indicated warming had occurred at the rate of 0.17°C/decade (SD = 0.067°C/decade) during the 40 year period of 1976–2015. Future scenarios suggest continued warming, although variation will occur within and among river networks due to differences in local climate forcing and stream responsiveness. NorWeST scenarios and data are available online in user‐friendly digital formats and are widely used to coordinate monitoring efforts among agencies, for new research, and for conservation planning.

Arizona, California, Colorado, Idaho, Montana, Nev↗

USGS2015

Empirical evaluation of the conceptual model underpinning a regional aquatic long-term monitoring program using causal modelling

Conceptual models are an integral facet of long-term monitoring programs. Proposed linkages between drivers, stressors, and ecological indicators are identified within the conceptual model of most mandated programs. We empirically evaluate a conceptual model developed for a regional aquatic and riparian monitoring program using causal models (i.e., Bayesian path analysis). We assess whether data gathered for regional status and trend estimation can also provide insights on why a stream may deviate from reference conditions. We target the hypothesized causal pathways for how anthropogenic drivers of road density, percent grazing, and percent forest within a catchment affect instream biological condition. We found instream temperature and fine sediments in arid sites and only fine sediments in mesic sites accounted for a significant portion of the maximum possible variation explainable in biological condition among managed sites. However, the biological significance of the direct effects of anthropogenic drivers on instream temperature and fine sediments were minimal or not detected. Consequently, there was weak to no biological support for causal pathways related to anthropogenic drivers’ impact on biological condition. With weak biological and statistical effect sizes, ignoring environmental contextual variables and covariates that explain natural heterogeneity would have resulted in no evidence of human impacts on biological integrity in some instances. For programs targeting the effects of anthropogenic activities, it is imperative to identify both land use practices and mechanisms that have led to degraded conditions (i.e., moving beyond simple status and trend estimation). Our empirical evaluation of the conceptual model underpinning the long-term monitoring program provided an opportunity for learning and, consequently, we discuss survey design elements that require modification to achieve question driven monitoring, a necessary step in the practice of adaptive monitoring. We suspect our situation is not unique and many programs may suffer from the same inferential disconnect. Commonly, the survey design is optimized for robust estimates of regional status and trend detection and not necessarily to provide statistical inferences on the causal mechanisms outlined in the conceptual model, even though these relationships are typically used to justify and promote the long-term monitoring of a chosen ecological indicator. Our application demonstrates a process for empirical evaluation of conceptual models and exemplifies the need for such interim assessments in order for programs to evolve and persist.

California, Colorado, Idaho, Montana, Nevada, Oreg↗

USGS2014

Annual variation of spawning Cutthroat Trout in a small Western USA stream: A case study with implications for the conservation of potamodromous trout life history diversity

Little is known about the variability in the spatial and temporal distribution of spawning potamodromous trout despite decades of research directed at salmonid spawning ecology and the increased awareness that conserving life history diversity should be a focus of management. We monitored a population of fluvial–resident Bonneville Cutthroat Trout Oncorhynchus clarkii utah in a tributary to the Logan River, Utah, from 2006 to 2012 to gain insight into the distribution and timing of spawning and what factors may influence these spawning activities. We monitored Bonneville Cutthroat Trout using redd surveys with multiple observers and georeferenced redd locations. We documented an extended spawning period that lasted from late April to mid‐July. The onset, median, and end of spawning was best predicted by the mean maximum water temperature during the first 13 weeks of the year ( F = 130. 4, df = 5, R 2 = 0.96, P < 0.0001) with spawning beginning and ending earlier in years that had warmer water temperatures prior to spawning. The distribution of redds was clumped each year and the relative density of redds was greater in a reach dominated by dams constructed by beavers Castor canadensis . Both dam failure and construction appeared to be responsible for creating new spawning habitat that was quickly occupied, demonstrating rapid temporal response to local habitat changes. Bonneville Cutthroat Trout appeared to establish and defend a redd for up to 2 d, and spawning most often occurred between similar‐sized individuals. Spawning surveys for potamodromous trout are an underutilized tool that could be used to better understand the distribution and timing of spawning as well as determine the size and trends of the reproducing portion of populations of management concern. Without efforts to document the diversity of this important aspect of potamodromous trout life history, prioritization of conservation will be problematic.

Utah↗

USGS2013

Exotic plant colonization and occupancy within riparian areas of the Interior Columbia River and Upper Missouri River basins, USA

Exotic plant invasions into riparia often result in shifts in vegetative composition, altered stream function, and cascading effects to biota at multiple scales. Characterizing the distribution patterns of exotic plants is an important step in directing targeted research to identify mechanisms of invasion and potential management strategies. In this study, we employed occupancy models to examine the associations of landscape, climate, and disturbance attributes with the colonization and occupancy patterns for spotted knapweed ( Centaurea stoebe L.), Canada thistle ( Cirsium arvense L., Scop.), and cheatgrass ( Bromus tectorum L.) in the riparia of headwater streams ( n  = 1,091) in the Interior Columbia River and Upper Missouri River Basins. We found relatively low occupancy rates for cheatgrass (0.06, SE = 0.02) and spotted knapweed (0.04, SE = 0.01), but moderate occupancy of Canada thistle (0.28, SE = 0.05); colonization rates were low across all species (<0.01). We found the distributions of spotted knapweed, Canada thistle, and cheatgrass to exhibit significant associations with both ambient climate conditions and anthropogenic and natural disturbances. We attribute the low to moderate occupancy and colonization rates to the relatively remote locations of our sample sites within headwater streams and urge consideration of means to prevent further invasions.

Interior Columbia River and Upper Missouri River b↗

USGS2012

A study of the spawning ecology and early life history survival of Bonneville Cutthroat Trout

We completed a large‐scale field experiment in four tributaries of the Logan River, Utah, where the largest metapopulation of imperiled Bonneville cutthroat trout Oncorhynchus clarkii utah persists. We documented the spatial and temporal distributions of spawners, quantified substrate use versus substrate availability, and evaluated differences in hatch and emergence fry success between and among sites in relation to habitat characteristics. We observed considerable variability in the timing, magnitude, and duration of spawning among study areas (streams), in part as a function of a variable, multipeaked hydrograph. Nevertheless, across study areas, >70% of redds were constructed on the final descending limb of the hydrograph. Despite large differences in the amount of spawning substrate available, Bonneville cutthroat trout utilized a narrow range of substrate and sizes (3–80 mm) similar to that utilized by other subspecies of cutthroat trout, albeit biased towards larger sizes. Water temperatures generally remained below the recommended range (6–17°C) for spawning; however, the viability of this metapopulation of cutthroat trout suggests that the recommended temperature range for spawning is overestimated for this subspecies and (or) does not account for local thermal adaptation. Hatch varied from 43% to 77% and emergence survival from 39% to 65% among streams, and within‐stream variability was substantial; both survival rates declined significantly as a function of increased fine sediment concentrations. Egg development rates were nearly 50% greater in a high‐elevation tributary where redd counts were also lowest. In high, mountain systems with short growing seasons, this incubation delay likely presents a significant growth disadvantage for age‐0 trout. Our research enhances our understanding of Bonneville cutthroat trout spawning ecology and early survival and provides critical information for aiding in the development of benchmarks for their recovery. Effective conservation efforts should be directed towards minimizing anthropogenic activities that result in excess sedimentation in their critical spawning tributaries.

Utah↗