Management and Conservation of Freshwater Systems III Posters
Presiding: E Marti, Centre d'Estudis Avancats de Blanes (CSIC); C Hoagstrom, South Dakota State University
NB33M-01 1330h
Variability in Response of Instream Habitat, and Fish and Macroinvertebrate Assemblages, to Riparian Forest Harvest in Northern Minnesota
We are evaluating the effects of high and low levels of riparian forest harvest, along eight, northern Minnesota streams, on fish and macroinvertebrate assemblages and instream habitat. The study is part of a larger project that includes water quality, vegetation and bird monitoring. Our design pairs streams with a high residual basal area (RBA) and a low RBA treatment. At each stream, control plots with no harvest and no riparian harvest were established and stream reaches were sampled downstream, within and upstream of all plots. Preharvest (2003) and postharvest (2004) data were collected from each stream and compared at the reach level. Fish were collected in one pass with a backpack electroshocker. Benthic macroinvertebrates were assessed following the US EPA family-level composited, multi-habitat rapid bioassessment protocol. Stream habitat was evaluated with a Quantitative Habitat Evaluation Index (QHEI) modified from the Minnesota Pollution Control Agency's habitat assessment protocol. Initial results indicate substantial variability in flow among sites, a significant variation (p<0.05) between years in QHEI and IBI scores, and differences within and between sites in macroinvertebrate species composition and abundance (species richness and %EPT). Continued monitoring will be required to assess the effects of riparian harvest.
NB33M-02 1330h
Response of Macroinvertebrate Assemblages to Experimental Additions of Coarse Woody Debri
Coarse woody debris (CWD) provides an important habitat for benthic macroinvertebrate assemblages in coastal plains streams, yet controlled experiments demonstrating the degree to which impaired (low-CWD) stream communities can be restored are lacking. We used field experiments to examine effects of CWD additions on benthic macroinvertebrates in 4 small sandy streams with contrasting bed stability from catchment disturbance at the Fort Benning Military Installation, Georgia, USA. We created debris dams by adding logs from pre-felled trees to 10 sites along 120-m reaches, and after 7 mo compared assemblages within debris dams (in underlying substrate) and outside of debris dams (~5 m from dams). As expected, mean macroinvertebrate density, biomass, and Shannon's H' were higher within vs outside of debris dams for 3 of the 4 streams. However, the stream with the most stable stream bed and highest amount of pre-addition CWD (which also drained the least disturbed catchment) showed opposite patterns with biomass, density, and H' being higher outside than inside the CWD additions. Our preliminary results suggest that additions of CWD in highly disturbed streams may increase benthic abundance, although similar additions to streams within relatively stable beds may have minor to no positive effects on benthos.
NB33M-03 1330h
Integrating Macroinvertebrate Community Analysis into the Management of Small Watersheds at the Township Level
Monitoring benthic communities in streams with small watersheds is useful for evaluating cumulative ecosystem impacts associated with changing land-use and can assist townships in managing for responsible development. Benthic sampling was conducted in the downstream reach of four Delaware River tributaries in Solebury Township, Bucks County, Pennsylvania, an area susceptible to increasing population density. The sampled streams originate in watersheds with varying land-use patterns and riparian areas, subjecting them to differing stressors. The macroinvertebrate communities sampled reflect variation in current land-uses and establish baseline conditions that can be utilized when implementing a water resources based approach that maintains natural resources and monitors the impacts of land-use changes on small watersheds. By combining benthic sampling with other measurements of biological, physical, and chemical components, this township is obtaining data that assists with protecting their water resources, consistent with water-based planning elements of its Comprehensive Plan. Comparisons are made to the existing baseline data on benthic communities in Delaware River tributaries located upstream and downstream of Solebury Township, where land is more and less developed. This analysis is being used to evaluate the priorities for more detailed assessments of the four sampled streams and determining a stream's ability to tolerate changing land-use.
NB33M-04 1330h
Gene Flow Patterns of the Mayfly Fallceon quilleri in San Diego County, California.
Management decisions and conservation strategies for freshwater invertebrates critically depend on an understanding of gene flow and genetic structure. We collected the mayfly Fallceon quilleri (Ephemeroptera: Baetidae) from 15 streams across three geographically distinct watersheds in San Diego County, California (San Dieguito, Santa Margarita, and Tijuana) and one site in Anza-Borrego desert. We sequenced a 667 base pair region of the mitochondrial DNA (COI) to assess genetic structure and gene flow. We found eight haplotypes across all populations. San Dieguito and Santa Margarita each contained six haplotypes. Tijuana and Anza Borrego each contained four haplotypes. The expected heterozygosity for San Dieguito, Santa Margarita, Tijuana, and Anza Borrego was 0.81, 0.83, 0.75, and 1.0, respectively. A hierarchical AMOVA analysis indicated restricted gene flow and a pairwise comparison indicated that Tijuana watershed differs significantly from San Dieguito and Anza Borrego. A haplotype cladogram revealed two internal ancestral haplotypes and six derived tip haplotypes that are unique to particular watersheds. These results suggest that Tijuana (the southernmost and the most impacted watershed) is more genetically distinct and isolated than the other watersheds sampled.
NB33M-05 1330h
Large Woody Debris in Forest Streams of the Canadian Boreal Shield: Implications for Riparian Management Strategies
The inputs, characteristics and function of large woody debris (LWD) were measured in 16 mid-order (3-7 m wide), moderate-gradient (1-5% slope) streams in mixedwood forests of the Boreal Shield in Ontario. Wood pieces in these streams were less abundant, smaller, less stable and, consequently, less functional than in streams of most other forest regions. The average frequency (19.9 pieces/100m), size (16.7 cm diameter), and aggregation (2.4 debris dams/100m) of LWD were less than in most previous studies. Fewer than 15% of the pools in these streams were influenced by LWD. The relatively-low LWD loading and influence on pool formation reflected the boulder-dominated substrates, where bed scouring or aggregation around LWD to influence channel morphology was limited. The dominance of coarse bed materials conferred a high degree of instability on many LWD pieces and increased the likelihood of fluvial transport. Given the limited functional role that LWD seems to have on channel morphology in these types of streams, selection-based logging in riparian zones of Boreal Shield streams may be a viable option to enhance riparian stand quality while maintaining stream channel integrity. Companion studies to examine other potential impacts of selection logging in riparian reserves of boreal streams are ongoing.
NB33M-06 1330h
Bear Valley Creek, Idaho Mining Enhancement: Fifteen Years Later
In 1988-89 an enhancement effort was initiated by the Shoshone-Bannock Tribes and Bonneville Power Administration in a mined section of Bear Valley Creek, Idaho. Monitoring and evaluation conducted between 1984 and 2004 above, within, and below the enhancement area included; changes in densities of non-anadromous salmonids, natural production of Chinook salmon Oncorhynchus tshawytscha, recovery of the macroinvertebrates, changes in surface and benthic sediment, and visual vegetation progression. Mean densities of non-anadromous salmonids in pools showed a significant increase from pre to post enhancement within and below the enhancement area. Chinook salmon parr numbers were significantly related to the number of redds the previous year. Preliminary results indicate that the macroinvertebrate community within the enhancement area may be recovering. Percent surface fine sediment decreased significantly from pre to post enhancement within and below the enhancement area. Trends in cumulative percent benthic fine sediment were similar above within and below the enhancement area indicating no new additional incorporation of fine sediment to the benthos. Photo point monitoring in 1989 and 2004 shows progression of vegetation development within the enhancement area with good cover achieved. Long term monitoring of Bear Valley Creek indicates recovery from the mining impact and successful enhancement effort.
NB33M-07 1330h
Comparison of the Reach Scale Habitat Characteristics of Historic and Current Ozark Hellbender (Cryptobranchus alleganiensis bishopi) Localities Using Standardized Assessment Protocols
Habitat degradation is typically cited as a reason for declines in Ozark hellbender populations. While habitat degradation is evident, many sites appear to contain suitable microhabitat, but do not support hellbender populations. We used three standardized protocols, US EPA Rapid Bioassessment Protocol (RBP), Ohio Qualitative Habitat Evaluation Index (QHEI), and Basin Area Stream Survey (BASS), to compare reach-scale habitat at nine locations within each of the Eleven Point (EP) and Spring (SR) rivers in the eastern Ozark Mountains. Sites were divided into Historically Present (HP), Currently Present (CP), and Reference Reaches (RR). Although EP sites scored consistently higher than SR sites for the RBP and QHEI, all sites scored close to the optimal levels. The BASS data were analyzed using PCA, and three resulting axes explained 52.8% of the variation. ANOVA of the PCA loading scores indicated significant differences between the rivers and between SRCP sites and both EPCP and EPHP sites. Parameters most associated with SR sites were rooted vegetation and embeddedness, whereas woody debris and bank cover were associated with EP stations. Our results suggest the Spring River is suffering from loss of riparian zones, thus, resulting in the degradation of in-stream habitat.
http://www.ozarkhellbender.com
NB33M-08 1330h
National Clusters of Lotic Macroinvertebrate Assemblages in the United States and Their Relationship to Existing Spatial Classification Schemes
Conducting biological assessments at a national scale requires a classification scheme to report results, define reference conditions, and interpret data. Analyzing stream biological assemblage data across the conterminous 48 United States is difficult due to the lack of synoptic assemblage data. In the last 10 years, however, the number and scope of bioassessments has increased dramatically. We compiled a national-scale database of lotic macroinvertebrate assemblages containing 4,950 sample sites from available national and state agency data. Cluster analysis (Bray-Curtis distance) and indicator species analysis were used to cluster the data, identify clusters, and describe them. We developed national clusters of macroinvertebrate assemblage groups that were well-described by indicator species and predicted using both discriminant function analysis and classification tree analysis. We also examined the relationship of existing spatial classification schemes to assemblage similarity. Existing schemes did not capture the majority of the within-group similarity expressed in biologically derived clusters. Schemes based on ecoregion, physiography, hydrologic units, and geopolitical boundaries had very similar mean within-group assemblage similarities.
NB33M-09 1330h
Characterizing the Invasion Front of the Rusty Crayfish, Orconectes Rusticus, in a Pennsylvania Stream
The rusty crayfish, Orconectes rusticus, was an unknown species in Pennsylvania during the last major assessment of crayfish as documented in a 1906 survey. An intensive survey of Lancaster County, Pennsylvania in 2000 revealed that O. rusticus had successfully invaded many streams. Orconectes rusticus are also sold in local bait shops suggesting its introduction was likely due to its use as bait. Orconectes rusticus has the potential to cause serious ecological harm to aquatic systems by displacing native crayfish species via competition and hybridization leading to alteration of food web dynamics. In order to predict the extent of invasions, identification of the physical and chemical parameters predisposing stream habitats to invasion is needed. Our objectives were to determine how a suite of physical and chemical parameters might influence the distribution of crayfish species along a stream continuum, with particular emphasis on characterizing the invasion front of Orconectes rusticus. Rather than an invasion front, we encountered a distinct invasion boundary created by a natural series of small waterfalls. Our data suggest that parameters such as water velocity, depth, pH, and temperature have little effect on the distribution and invasion of Orconectes rusticus along a stream continuum when natural barriers are present.
NB33M-10 1330h
Comparing ANNs, EAs, and Trees: a basic machine-learning approach to predictive environmental models.
Machine learning techniques for ecological applications or "eco-informatics" are becoming increasingly useful and accessible for ecologists. We evaluated the predictive ability of three commercially available (i.e. user-friendly) software packages for artificial neural networks (ANNs), evolutionary algorithms (EAs), and classification/regression trees (Trees). We analyzed fish and habitat data for streams in the mid-Atlantic region of the U.S., which was collected by the U.S. Environmental Protection Agency (EPA). The data includes over 200 environmental descriptors summarizing watershed, stream, and water chemistry characteristics in addition to derived fish community metrics (i.e. richness, IBI scores, % exotics). In our analysis we predicted individual species presence/absence and fish community metrics as a function of these local and regional scale habitat variables. Predictive ability is evaluated with independent validation data. These approaches could prove especially useful for conservation or management applications where ecologists seek to utilize the most comprehensive data to make predictions at various scales. By employing "user-friendly" software we hope to show that ecologists, without extensive knowledge of computational science, can benefit from these techniques by extracting more information about complex ecosystems. Relative strengths and weaknesses of these three approaches are compared and recommendations for their use in conservation applications are presented.