|Progress and Results
The valued native fish communities that inhabit Kansas streams and rivers are threatened by human impacts, such as dams. Dam impacts on biodiversity can be mediated by natural habitat heterogeneity and implemented through dam-related habitat alterations. In order to help managers make science-based decisions on the impact of dams on native fish communities, the Neosho River research team (Jane Fencl, M.S. student; Sean Hitchman, Ph.D.; Dr. Joseph Smith, post-doctoral fellow; and Dr. Martha Mather, Principal Investigator) are sampling fish communities and instream habitat at dammed and undammed sites within the upper Neosho River, KS. Ultimately, this research can be used to develop and test a spatially-explicit, science-based decision support tool for managing fish and dams in Great Plains stream and river networks.
In consultation with our project liaisons at Kansas Department of Wildlife, Fisheries, and Parks (KDWPT), our research efforts have focused on the collection of fish and habitat data at sites with dams as well as at paired undammed reference sites. As a team, we have identified the best gear to use to sample fish upstream and downstream of dammed and undammed sites. Our gear test showed that the mini-Missouri trawl, the gear we chose to use for all stream sampling, caught as many species as other common stream sampling gears and more individuals than other gears. Once we determined that the mini-Missouri trawl performed as well as other gears, we conducted a trawl length experiment to determine the optimal trawl length (30 m). These results have been incorporated into our standardized sampling protocols.
In 2012, we sampled three dams and one undammed site. Fish and habitat were sampled at 20 transects above and below all dams (or the site centerline of the undammed location) resulting in 90 fish samples at transects around dams. To assess microhabitat (width, depth, velocity, substrate), we sampled 42 habitat transects at four sites (168 microhabitat samples). In addition, we categorized mesohabitat (pool, riffle, run, glide) across 16.1 km of stream for a total of 65, 100-m long mesohabitat samples. Within these mesohabitats, we sampled fish with an additional 44 trawls.
In 2013, we expanded the number of sample sites from 4 to 11 and extended the distances we sampled at each site to include 22 transects that extended 3 km above and below each dam or undammed site centerline. We sampled habitat and native fish communities using standardized methods at 22 transects (13 transects downstream and 9 transects upstream of each dam or centerline at undammed sites) at 11 sites. At these 11 sites, in 2013, collectively we sampled fish and habitat at 52 upstream transects, 70 downstream transects, 70 transects at undammed sites, 73 additional transects to address temporal variation, for a total of 265 fish and habitat transect samples. At these same 11 sites, in 2013, we also collected samples to identify the relationship between fish communities and specific habitat types. Specifically, at 11 locations, we sampled five replicates of four mesohabitat types (pool, riffle, run, and glide) during 64 days of field sampling. This sampling resulted in 220 habitat-specific fish samples (42 total species), 220 stream width measurements, 1,100 depth, flow velocity, substrate measurements, and mesohabitat data for patch mosaics across 51 km of stream. At the six dam sites, we quantified the geomorphic dam footprint to identify the spatial extent of the dam effect. This helped us interpret dam impacts on fish communities.
This research will advance riverscape-scale understanding of the structure and function of aquatic ecosystems. In addition, managers will be able to place conservation actions in a synthetic, landscape-scale, multiple-stressor context. As such, our research will benefit management. Jane Fencl's M.S. research (defended April 2015) focused on how dams alter fish communities. Jane has one paper published and a second paper in review. Sean Hitchman's Ph.D. research examines patterns, drivers, and consequences of habitat heterogeneity in stream networks. His dissertation will include three chapters of which one is almost ready for review. These research products are described in more detail below.
Jane Fencl Thesis: How Big of an Effect Do Small Dams Have?: Using Ecology and Geomorphology to Quantify Impacts of Low-Head Dams on Fish Biodiversity.
In contrast to well documented adverse impacts of large dams, little is known about how smaller low-head dams affect fish biodiversity. Over 2,000,000 low-head dams fragment United States streams and rivers and can alter biodiversity. The spatial impacts of these common low-head dams on geomorphology and ecology are largely untested. A select review of how intact low-head dams affect fish species identified four methodological inconsistencies that impede our ability to generalize about the ecological impacts of low-head dams on fish biodiversity. This project tested the effect of low-head dams on fish biodiversity (1) upstream vs. downstream at dams and (2) downstream of dammed vs. undammed sites. Fish assemblages for both approaches were evaluated using three community summary metrics and seven habitat guilds (based on empirically based species occurrence in pools, riffles, and runs). Downstream of dams vs. undammed sites, this project tested if (a) spatial extent of dam disturbance, (b) reference site choice, and (c) site variability altered fish biodiversity at dams. Based on information from geomorphic literature, this research quantified the spatial extent of low-head dam impacts using width, depth, and substrate. Sites up- and downstream of dams had different fish assemblages regardless of the measure of fish biodiversity. Richness, abundance and Shannon's index were significantly lower upstream compared to downstream of dams. In addition, only three of seven habitat guilds were present upstream of dams. Methodological decisions about spatial extent and reference choice affected observed fish assemblage responses between dammed and undammed sites. For example, species richness was significantly different when comparing transects within the spatial extent of dam impact but not when transects outside the dam footprint were included. Site variability did not significantly influence fish response. Furthermore, these small but ubiquitous disturbances may have large ecological impacts because of their potential cumulative effects. Therefore, low-head dams need to be examined using a contextual riverscape approach. How low-head dam studies are designed has important ecological insights for scientific generalization and methodological consequences for interpretations about low-head dam effects. This research provides a template on which to build this approach that will benefit both ecology and conservation.
Jane S. Fencl, Martha E. Mather, Katie H. Costigan, Melinda D. Daniels. How Big of an Effect Do Small Dams Have?; Using Geomorphological Footprints to Quantify Spatial Impact of Low-Head Dams and Identify Patterns of Across-Dam Variation.
Longitudinal connectivity is a fundamental characteristic of rivers that can be disrupted by natural and anthropogenic processes. Dams are significant disruptions to streams. Over 2,000,000 low-head dams (<7.6 m high) fragment United States rivers. Despite potential adverse impacts of these ubiquitous disturbances, the spatial impacts of low-head dams on geomorphology and ecology are largely untested. Progress for research and conservation is impaired by not knowing the magnitude of low-head dam impacts. Based on the geomorphic literature, we refined a methodology that allowed us to quantify the spatial extent of low-head dam impacts (herein dam footprint), assessed variation in dam footprints across low-head dams within a river network, and identified select aspects of the context of this variation. Wetted width, depth, and substrate size distributions upstream and downstream of six low-head dams within the Upper Neosho River, Kansas, United States of America were measured. Total dam footprints averaged 7.9 km (3.0-15.3 km) or 287 wetted widths (136-437 wetted widths). Estimates included both upstream (mean: 6.7 km or 243 wetted widths) and downstream footprints (mean: 1.2 km or 44 wetted widths). Altogether the six low-head dams impacted 47.3 km (about 17%) of the mainstem in the river network. Despite differences in age, size, location, and primary function, the sizes of geomorphic footprints of individual low-head dams in the Upper Neosho river network were relatively similar. The number of upstream dams and distance to upstream dams, but not dam height, affected the spatial extent of dam footprints. In summary, ubiquitous low-head dams individually and cumulatively altered lotic ecosystems. Both characteristics of individual dams and the context of neighboring dams affected low-head dam impacts within the river network. For these reasons, low-head dams require a different, more integrative, approach for research and management than the individualistic approach that has been applied to larger dams.
Jane S. Fencl, Martha E. Mather, Joseph M. Smith, Sean M. Hitchman. The Blind Men Meet The Elephant at the Dam: Alternative Perspectives Obscure Low-Head Dam -- Biodiversity Relationships.
Dams are ubiquitous environmental impacts. The ability to provide science-based generalizations across dam sites and research studies is critical for sustainable management of these disturbances because empirical data can only be collected at a few of the existing 2 million U.S. low-head dams that will require future repair or removal. Just as individual blind men disagree about the structure of an elephant based on an examination of isolated body parts, uncoordinated, individualized dam research can lead to conflicting results and unnecessary disagreements about ecological dam impacts unless alternative research perspectives are explicitly integrated. To initiate this essential synthesis of how dams impact biodiversity, we concurrently quantified two categories of dam effects (spatial and taxonomic) using two spatial components (1-above vs below dams, 2-undammed vs dammed comparisons) and 11 taxonomic components (3 assemblage summaries, 8 guild metrics for fish biodiversity). At six low-head dams and five undammed sites in the Upper Neosho subbasin, KS, USA, sites below dams had dramatically more diverse fish assemblages than sites above dams for all taxonomic components. These upstream biodiversity deserts link low-head dams to environmental degradation. Sites below dams were subtly different from undammed sites. When dam impacts were strong (above vs below dams), all taxonomic metrics detected differences. When the dam impacts were subtle (undammed vs dammed sites), guild metrics were needed to evaluate ecological function. Because research perspective influenced conclusions about strength and type of ecological dam effects, here we propose a framework to integrate the entire elephant (e.g., multiple ecological research perspectives about dam-biodiversity relationships) that can provide scientifically sound generalizations across dam sites and research studies when placed within a broader interdisciplinary (ecological, physical, social science) context.
Sean M. Hitchman, Martha E. Mather, Joseph M. Smith, Jane S. Fencl. A Mosaic-Based Approach to Biodiversity in Freshwater Ecosystems.
A mosaic-based approach can identify keystone habitats, increase scientific understanding of organismal-habitat relationships, and facilitate conservation of native biodiversity in disturbed freshwater ecosystems. Rivers and streams provide valuable goods and services to society. Freshwater biodiversity is a key attribute of streams and rivers. Organisms that comprise biodiversity are influenced by habitat. A suite of anthropogenic impacts, exacerbated by climate change, threaten aquatic habitats and freshwater biodiversity. Because many ecological processes require spatially-connected data, a mosaic approach offers a scientific foundation for understanding and managing a range of disturbance-related conservation problems. Here, we ask if patterns of aquatic biodiversity differ for habitat mosaics (i.e., connected series of individual juxtaposed habitats) compared to isolated, individual habitats. Traditional approaches to conserving native biodiversity will be inadequate if mosaics create different patterns of biodiversity than isolated mesohabitats. Our sampling of fish and habitat along 10 3-km sites within the Upper Neosho subdrainage, KS, from June-August 2013, yielded four important insights. First, mesohabitats (pool, riffle, run, and glide) formed discrete habitat categories based on three physical characteristics. Together juxtaposed mesohabitats formed diverse mosaics. Second, multivariate, community analysis on three fish biodiversity data sets confirmed guild-based organism-habitat associations identified from type and strength of species-mesohabitat associations. Third, patterns of biodiversity were different in mosaics than for isolated mesohabitats. Fourth, riffles acted as keystone habitats in that mosaics with more riffle mesohabitat (<5% of sampled area) had higher native species diversity. Links among human impacts, water use, land use change, climate change predictions, precipitation, discharge, aquatic habitat, and biodiversity make a suite of diverse and often complex spatial and temporal impacts inevitable in disturbed aquatic ecosystems. Thus, developing a new approach for quantifying connected biodiversity-habitat relationships is essential for biodiversity baselines to which future human impacts and climate disturbances can be compared. A mosaic approach can provide this framework for examining ecological processes in both reference and disturbed ecosystems.
Fencl, Jane (M.S. 2015; advisor Mather). How big of an effect do small dams have?: using ecology and geomorphology to quantify impacts of low-head dams on fish biodiversity. M.S. Thesis, Kansas State University.
Fencl J. S., M. E. Mather, K. B. Costigan, and M. D. Daniels. 2015. How big of an effect do small dams have?; Using geomorphological footprints to quantify spatial impact of low-head dams and identify patterns of across-dam variation. PLoS ONE 10(11): e0141210. doi:10.1371/journal.pone.0141210
Hitchman, S.M., M.E. Mather, J.M. Smith and J.S. Fencl. 2016. Viewing streams as a habitat mosaic; implications for riverscape ecology and stream conservation. Part of the symposium entitled "Fish Research and Conservation in the 'Scapes: Needs, Progress, Challenges and Opportunities" at the American Fisheries Society. Kansas City, MO.
Fencl J.S., Mather M.E., Smith J.M., and S.M. Hitchman. 2015. Quantifying river fragmentation: impacts of low-head dams on geomorphology and fish biodiversity in the Neosho River, Kansas. 75th Midwest Fish and Wildlife Conference; Indianapolis, Indiana.
Hitchman, S.M., M.E. Mather, J.M. Smith and J.S. Fencl. 2015. Are riffles keystone habitats in a low-gradient prairie stream?; implications for riverscape ecology and stream conservation. American Fisheries Society. Portland, Oregon.
Fencl, J.S., M.E. Mather, S.M. Hitchman and J.M. Smith. 2014. Quantifying impacts of river fragmentation: How low-head dams alter geomorphology, fish biodiversity, and habitat in the Neosho River, Kansas, American Fisheries Society Meeting, Quebec, Canada.
Hitchman, S.M., M.E. Mather, J.M. Smith and J.S. Fencl. 2014. Does heterogeneity in habitat type, size, and arrangement influence patterns of fish biodiversity in the Neosho River, Kansas? American Fisheries Society. Quebec City, Quebec, Canada.
Jane Fencl, Martha Mather, Sean Hitchman and Joseph Smith. 2014. Quantifying impacts of river fragmentation: how low-head dams affect distributions of fish biodiversity and habitat in the Neosho River, Kansas. Graduate Student Research Forum, Division of Biology, Kansas State University.
Sean Hitchman, Martha Mather, Jane Fencl and Joseph Smith. 2014. Heterogeneity influences patters of fish biodiversity at multiple scales. Graduate Student Research Forum, Division of Biology, Kansas State University.
Fencl, J. S., K. H. Costigan, M. E. Mather and S. M. Hitchman. 2014. How long is the dam footprint?: Applying methodology that quantifies the geomorphic extent of low-head dams in the Neosho River basin, KS. Kansas Natural Resources Conference, Wichita, KS.
Hitchman, S.M., M.E. Mather, J.M. Smith, and J.S. Fencl. 2014. Do Fragstats sink or swim?; calculating metrics of heterogeneity for aquatic macrohabitat within the Neosho River, KS. Kansas Natural Resources Conference, Wichita, KS.
Smith, J. M., M. E. Mather, J. Fencl, and S, M. Hitchman. 2012. Stopping biodiversity loss: An evaluation of metrics that quantify the composition of fish communities in aquatic ecosystems. Midwest American Fisheries Society Meeting, Wichita, KS.