Katie N. Bertrand

An evaluation of single-pass versus multiple-pass backpack electrofishing to estimate trends in species abundance and richness in prairie streams

Abstract Backpack electrofishing is a common method used to compare total species richness and relative abundance of stream fishes across space and time. However, as with any sampling method, it is important to evaluate the sampling effort necessary to capture patterns of variation in fish assemblage structure across samples. Thus, we evaluated the efficacy of single-pass versus multiple-pass backpack electrofishing for minnows and darters in intermittent prairie streams. We found that in 14 of 19 three-pass electrofishing samples, we detected all species during the first pass. The samples where we missed species on the first pass were in pools with six to nine species, suggesting a single-pass sample worked best for pools with lower species richness. We also found that both the raw abundance (i.e., catch rates) and rank abundance of four common species based on the first pass is highly concordant with the second and third passes. Nevertheless, differences in capture efficiency varied by species and density. In particular, our ability to deplete a species from a stream pool was highly variable when fish densities were low, and for Phoxinus erythrogaster, it was variable across all densities. Overall, our data suggest single-pass electrofishing can be used to detect spatial and temporal trends in abundance and species richness given standardized effort, but may not be representative of absolute population densities.

Comparing Ecosystem Goods and Services Provided by Restored and Native Lands

ABSTRACT We determined the relative benefits for eight categories of ecosystem goods and services associated with native and restored lands across the conterminous United States. Less than 10% of most native US ecosystems remain, and the proportion that is restored varies widely by biome. Restored lands offer 31% to 93% of native land benefits within a decade after restoration, with restored wetlands providing the most economic value and deserts providing the least. Restored ecosystems that recover rapidly and produce valuable commodities return a higher proportion of total value. The relative values of the benefits provided by restoration vary both by biome and by the ecosystem goods and services of interest. Our analysis confirms that conservation should be the first priority, but that restoration programs across broad geographic regions can have substantial value. “No net loss” policies should recognize that restored lands are not necessarily equivalent to native areas with regard to estimated ecosystem benefits.

Consumer return chronology alters recovery trajectory of stream ecosystem structure and function following drought

Consumers are increasingly being recognized as important drivers of ecological succession, yet it is still hard to predict the nature and direction of consumer effects in nonequilibrium environments. We used stream consumer exclosures and large outdoor mesocosms to study the impact of macroconsumers (i.e., fish and crayfish) on recovery of intermittent prairie streams after drying. In the stream, macroconsumers altered system recovery trajectory by decreasing algal and macroinvertebrate biomass, primary productivity, and benthic nutrient uptake rates. However, macroconsumer influence was transient, and differences between exclosures and controls disappeared after 35 days. Introducing and removing macroconsumers after 28 days resulted mainly in changes to macroinvertebrates. In mesocosms, a dominant consumer (the grazing minnow Phoxinus erythrogaster) reduced macroinvertebrate biomass but had little effect on algal assemblage structure and ecosystem rates during recovery. The weak effect of P. erythrogaster in mesocosms, in contrast to the strong consumer effect in the natural stream, suggests that both timing and diversity of returning consumers are important to their overall influence on stream recovery patterns. Although we found that consumers significantly altered ecosystem structure and function in a system experiencing rapid changes in abiotic and biotic factors following disturbance, consumer effects diminished over time and trajectories converged to similar states with respect to primary producers, in spite of differences in consumer colonization history. Thus, consumer impacts can be substantial in recovering ecosystems and are likely to be dependent on the disturbance regime and diversity of the consumer community.

Effects of the herbivorous minnow, southern redbelly dace (Phoxinus erythrogaster), on stream productivity and ecosystem structure

We used field and mesocosm experiments to measure effects of southern redbelly dace (Phoxinus erythrogaster), a grazing minnow, on stream ecosystem structure and function. Ecosystem structure was quantified as algal filament length, algal biomass, size distribution of particulate organic matter (POM), algal assemblage structure, and invertebrate assemblage structure, whereas ecosystem function was based on gross and net primary productivity. Our experiments showed that moderate densities of Phoxinus temporarily reduced mean algal filament length and mean size of POM relative to fishless controls. However, there was no detectable effect on algal biomass or ecosystem primary productivity. Several factors could explain the lack of effect of Phoxinus on primary productivity including increased algal production efficiency in grazed treatments or increased grazing by other organisms in fishless treatments. The inability of Phoxinus to reduce algal biomass and system productivity contrasts with experimental results based on other grazing minnows, such as the central stoneroller (Campostoma anomalum), and questions the generality of grazer effects in stream ecosystems. However, environmental venue and the spatial and temporal scale of ecosystem measurements can greatly influence the outcome of these experiments.

Long Term Trends and Outlook for Mountain Sucker in the Black Hills of South Dakota

Abstract The extirpation of native fishes is a major concern in North America, and an understanding of population trends of imperiled fishes is critical to their management and conservation. Mountain sucker Catostomus platyrhynchus is a stream fish native to the Intermountain Region of western North America, and populations in the Black Hills of South Dakota represent the easternmost range of the species. Recently, stream surveys raised concerns about the status of mountain sucker populations in South Dakota. The purpose of this study was to document the current distribution of mountain sucker in the Black Hills of South Dakota for comparison with historic records. We analyzed stream fisheries survey data collected between 1960 and 2010 and found that mountain sucker density generally declined at three nested spatial scales: sample reach, stream, and watershed. At 14 sample reaches and two streams mountain sucker appear extirpated, whereas in remaining areas they persist in varying densities. In 2009–2010, populations exceeding densities of 0.01 fish·m−2 persisted only in Whitewood, Elk, Boxelder, and Bear Butte Creeks, and tributaries to Upper Rapid Creek. Our study documents the decline of a native fish in the Black Hills of South Dakota, and a comprehensive ecosystem management approach is needed to mitigate further loss of mountain sucker and co-occurring native species, while at the same time maintaining a highly valued non-native salmonid fishery.

AN ASSESSMENT OF THE LETHAL THERMAL MAXIMA FOR MOUNTAIN SUCKER

ABSTRACT. Temperature is a critical factor in the distribution of stream fishes. From laboratory studies of thermal tolerance, fish ecologists can assess whether species distributions are constrained by tolerable thermal habitat availability. The objective of this study was to use lethal thermal maxima (LTM) methodology to assess the upper thermal tolerance for mountain sucker Catostomus platyrhynchus, a species of greatest conservation need in the state of South Dakota. Adult fish were captured from wild populations in the Black Hills of South Dakota and acclimated to 20, 22.5, and 25 °C. Four endpoints (3 sublethal, 1 lethal) were recorded, with death being the most precise (lowest SE, easily discernible). The LTM for mountain sucker was 34.0 °C at 25 °C acclimation, 33.2 °C at 22.5 °C acclimation, and 32.9 °C at 20 °C acclimation. Compared to co-occurring species in the Black Hills, the LTM of mountain sucker is higher than that of salmonids but lower than that of 3 cypriniforms. Mountain sucker LTM is intermediate compared to other species in the family Catostomidae. These results suggest that the mountain sucker is not currently limited by water temperatures in the Black Hills but may be affected by stream warming as a result of climate change.

Size-Dependent Trophic Patterns of Pallid Sturgeon and Shovelnose Sturgeon in a Large River System

Abstract This study compared patterns of δ15N and δ13C enrichment of pallid sturgeon Scaphirhynchus albus and shovelnose sturgeon S. platorynchus in the Missouri River, United States, to infer their trophic position in a large river system. We examined enrichment and energy flow for pallid sturgeon in three segments of the Missouri River (Montana/North Dakota, Nebraska/South Dakota, and Nebraska/Iowa) and made comparisons between species in the two downstream segments (Nebraska/South Dakota and Nebraska/Iowa). Patterns in isotopic composition for pallid sturgeon were consistent with gut content analyses indicating an ontogenetic diet shift from invertebrates to fish prey at sizes of >500-mm fork length (FL) in all three segments of the Missouri River. Isotopic patterns revealed shovelnose sturgeon did not experience an ontogenetic shift in diet and used similar prey resources as small (<500-mm FL) pallid sturgeon in the two downstream segments. We found stable isotope analysis to be an effective tool for ...

Influence of macroconsumers, stream position, and nutrient gradients on invertebrate assemblage development following flooding in intermittent prairie streams

Climate change in the US Great Plains is expected to result in less frequent but more severe floods. This will affect hydrologic cycles, stream organisms, and ultimately ecosystem structure and function. We examined factors influencing invertebrate assemblages following flooding in 3 reaches (20 pools) of Kings Creek, an intermittent prairie stream on the Konza Prairie Biological Station, using replicated macroconsumer enclosures (fishless, dace, shiners, ambient). Invertebrate densities and biomass increased rapidly following scouring, including rapid colonizing taxa and relatively long-lived taxa, but macroconsumers had no significant effects. Rather, distance, which was negatively correlated with the concentration of dissolved inorganic nitrogen, from the downstream confluence with a larger stream significantly influenced assemblage structure, with higher richness and greater nutrient concentrations closer to the confluence. Results support previous findings that recovery patterns following flooding in this grassland stream are strongly influenced by proximity to refuges. Furthermore, physical rather than biological factors appear more influential in structuring invertebrate assemblages in these frequently disturbed systems. Predicted increases in the intensity and duration of hydrologic disturbances will increase direct impacts on stream communities, relative to indirect effects through potential changes in macroconsumer communities. Human activities that alter refuges may further impede recovery following hydrologic disturbances.

Effects of Common Carp on Trophic Dynamics of Sport Fishes in Shallow South Dakota Water Bodies

AbstractThe Common Carp Cyprinus carpio is one of the most common freshwater fish invaders worldwide, creating adverse effects on water quality and impacting ecosystem structure and function. To assess how Common Carp impact food web dynamics, we compared the trophic dynamics of Bluegills Lepomis macrochirus and Largemouth Bass Micropterus salmoides in three lakes containing Common Carp populations with the trophic dynamics in three lakes without Common Carp. All six lakes were located in eastern South Dakota. Stable isotope analysis was used to estimate trophic positions and indicate energy sources utilized by adult and age-0 fish. Additionally, diets of age-0 Bluegills were analyzed to assess whether Common Carp were inhibiting ontogenetic diet shifts, and bomb calorimetry was used to evaluate differences in energy density of age-0 fish prior to winter. Age-0 fish and adult Bluegills derived significantly more energy from pelagic sources in the systems populated with Common Carp. Adult Bluegills in Comm...

Motivations for enrollment into the Conservation Reserve Enhancement Program in the James River Basin of South Dakota

ABSTRACT The Conservation Reserve Enhancement Program (CREP) targets high-priority conservation needs (e.g., water quality, wildlife habitat) by paying landowners an annual rental rate to remove environmentally sensitive or agriculturally unproductive lands from rowcrop production, and then implement conservation practices on these lands. This study examined motivations of South Dakota landowners for enrolling in the James River Basin CREP. All 517 newly enrolled landowners were mailed a questionnaire in 2014 measuring demographics, behaviors, opinions, and motivations (60% response rate). Cluster analysis of 10 motivations for enrolling identified three motivation groups (wildlife = 40%, financial = 35%, environmental = 25%). The financial group had the youngest mean age (62 years), followed by the wildlife (65) and environmental groups (68). Among respondents, 43% favored the public access requirement of this CREP with the environmental group most in favor. Understanding landowner enrollment motivations and decision criteria will assist in strategies (e.g., financial incentives, increasing yield via habitat restoration) for increasing future participation.