Although forested riparian zones have been shown to reduce sediment and nutrient inputs and impro... more Although forested riparian zones have been shown to reduce sediment and nutrient inputs and improve habitat conditions in agricultural streams, conflicting results from previous studies suggest biotic integrity may not be restored by the presence of riparian buffers in highly degraded watersheds. To determine if forest buffers can ameliorate cropland agricultural impacts on stream communities, we examined the effects of riparian forest and watershed agricultural land use on macroinvertebrate and fish assemblages in headwater streams. Study sites were equally divided into three land use groups that covered the range of riparian forest and agriculture in the watershed. Sampling was conducted seasonally over three years to explore temporal patterns in biotic assemblages related to land use, instream habitat, and water quality parameters. Streams with low percent forest buffer had significantly higher daily maximum temperature, nitrate-nitrogen levels, and primary productivity than the ...
ABSTRACT We examined nine headwater streams with a gradient of riparian forest buffer and watersh... more ABSTRACT We examined nine headwater streams with a gradient of riparian forest buffer and watershed agriculture to determine the extent to which riparian buffers can ameliorate the effects of agricultural activities on stream ecosystems. Sampling was conducted seasonally over three years to explore temporal patterns in macroinvertebrate and fish assemblages related to land use, in-stream habitat, and water quality parameters. Streams with low percent forest buffer had significantly higher daily maximum temperature, nitrate-nitrogen levels, and primary productivity than high forest buffer streams. Although there were greater abundances and biomass of macroinvertebrates and fish in streams with low forest buffer, assemblages were dominated by pollution tolerant taxa. Streams with high percent forest buffer and low watershed agriculture had the best biotic integrity and the most complex trophic structure. Ordinations based on fish assemblages indicated that streams sites grouped by land use category due to distinct differences in trophic patterns. Stable isotopes analyses were also performed to examine trophic interactions and energy flow within each stream to determine how land use changes affect in-stream food web interactions. Our results suggest that riparian forest buffers can reduce agricultural impacts on stream ecosystems and have implications for managing and restoring riparian areas in agricultural watersheds.
We examined nine headwater streams with a gradient of riparian forest and agricultural land use t... more We examined nine headwater streams with a gradient of riparian forest and agricultural land use to determine the effect of riparian and watershed land use on stream communities. Sampling was conducted seasonally over three years to explore temporal patterns in macroinvertebrate and fish assemblages related to land use, in-stream habitat, and water quality parameters. While there were significant seasonal and annual differences, relationships among streams with different land use types were relatively consistent. Macroinvertebrate and fish abundance and biomass were significantly higher in streams with low percent riparian forest compared to streams with high percent riparian forest. Macroinvertebrate HBI and fish IBI scores improved with increasing percent riparian forest suggesting better stream water quality with increasing forest buffer. Streams with the highest percent forest buffer and lowest percent watershed agriculture had the highest biotic integrity, greatest abundance of ...
We examined nine headwater streams with a gradient of riparian forest and watershed agriculture t... more We examined nine headwater streams with a gradient of riparian forest and watershed agriculture to determine the extent to which riparian buffers can mitigate the effects of agricultural activities on stream ecosystems. Sampling was conducted seasonally over two years to explore temporal patterns in fish assemblages related to land use, in-stream habitat, and water quality parameters. Stable isotopes analysis (δ13C and δ15N) was performed to determine how land use and seasonal changes affect energy flow and in-stream food web structure. Results suggest significant community-wide isotopic shifts occurred among streams and seasons. Agricultural streams with low percent forest buffer had compressed food webs based primarily on periphytic energy sources with shorter food chain length compared to forested streams. Streams with high percent riparian forest had higher variability in δ13C than low forest buffer streams, suggesting consumers utilized a greater variety of carbon sources and i...
We examined nine headwater streams with a gradient of riparian forest buffer and watershed agricu... more We examined nine headwater streams with a gradient of riparian forest buffer and watershed agriculture to determine the extent to which riparian buffers can ameliorate the effects of agricultural activities on stream ecosystems. Sampling was conducted seasonally over three years to explore temporal patterns in macroinvertebrate and fish assemblages related to land use, in-stream habitat, and water quality parameters. Streams with low percent forest buffer had significantly higher daily maximum temperature, nitrate-nitrogen levels, and primary productivity than high forest buffer streams. Although there were greater abundances and biomass of macroinvertebrates and fish in streams with low forest buffer, assemblages were dominated by pollution tolerant taxa. Streams with high percent forest buffer and low watershed agriculture had the best biotic integrity and the most complex trophic structure. Ordinations based on fish assemblages indicated that streams sites grouped by land use cat...
ABSTRACT Crustacean zooplankton exhibit a variety of defenses which deter predation by gape-limit... more ABSTRACT Crustacean zooplankton exhibit a variety of defenses which deter predation by gape-limited (e.g., planktivorous fish) and size-dependent (e.g., invertebrate) predators. Cyclomorphic changes in morphology of a prey item, such as production of head and tail spines, presumably decrease the likelihood of capture and consumption by either class of predator. Daphnia lumholtzi exhibits extreme cyclomorphic features throughout its life history. We investigated the vulnerabilities of different size classes of D. lumholtzi and the non-spined Daphnia pulex to the invertebrate predator Leptodora kindti. In trials with single prey species, L. kindti consumed D. lumholtzi neonates at a higher rate than D. pulex neonates, medium D. pulex, and large D. pulex. When the daphnids were offered together in equal numbers, L. kindti selected D. lumholtzi at a faster rate than D. pulex in all size classes. Our results suggest that instead of providing protection, D. lumholzi's helmet and tail spine may increase likelihood of detection and capture by L. kindti, while decreasing the probability of escape.
It is critical for fisheries ecologists to evaluate physiological responses to understand how fis... more It is critical for fisheries ecologists to evaluate physiological responses to understand how fish cope with anthropogenic disturbances that have the potential to cause population declines. Few studies have quantified the underlying physiological mechanisms that dictate the ability of fish to cope with human disturbance. The purpose of this study was to quantify the influence of watershed and segment-scale land-use disturbance on the physiological responses of stream fish. To test this, Creek chub were collected from replicated agricultural (disturbed) and forested (control) streams and subjected to heat and hypoxia stressors to evaluate blood and whole animal physiological responses. No differences in baseline physiological parameters were found in fish sampled immediately from streams within forested or agricultural streams at either scale. However, when exposed to low oxygen conditions in the lab, creek chubs from forested watersheds had a higher stress response and greater ion l...
Although forested riparian zones have been shown to reduce sediment and nutrient inputs and impro... more Although forested riparian zones have been shown to reduce sediment and nutrient inputs and improve habitat conditions in agricultural streams, conflicting results from previous studies suggest biotic integrity may not be restored by the presence of riparian buffers in highly degraded watersheds. To determine if forest buffers can ameliorate cropland agricultural impacts on stream communities, we examined the effects of riparian forest and watershed agricultural land use on macroinvertebrate and fish assemblages in headwater streams. Study sites were equally divided into three land use groups that covered the range of riparian forest and agriculture in the watershed. Sampling was conducted seasonally over three years to explore temporal patterns in biotic assemblages related to land use, instream habitat, and water quality parameters. Streams with low percent forest buffer had significantly higher daily maximum temperature, nitrate-nitrogen levels, and primary productivity than the ...
ABSTRACT We examined nine headwater streams with a gradient of riparian forest buffer and watersh... more ABSTRACT We examined nine headwater streams with a gradient of riparian forest buffer and watershed agriculture to determine the extent to which riparian buffers can ameliorate the effects of agricultural activities on stream ecosystems. Sampling was conducted seasonally over three years to explore temporal patterns in macroinvertebrate and fish assemblages related to land use, in-stream habitat, and water quality parameters. Streams with low percent forest buffer had significantly higher daily maximum temperature, nitrate-nitrogen levels, and primary productivity than high forest buffer streams. Although there were greater abundances and biomass of macroinvertebrates and fish in streams with low forest buffer, assemblages were dominated by pollution tolerant taxa. Streams with high percent forest buffer and low watershed agriculture had the best biotic integrity and the most complex trophic structure. Ordinations based on fish assemblages indicated that streams sites grouped by land use category due to distinct differences in trophic patterns. Stable isotopes analyses were also performed to examine trophic interactions and energy flow within each stream to determine how land use changes affect in-stream food web interactions. Our results suggest that riparian forest buffers can reduce agricultural impacts on stream ecosystems and have implications for managing and restoring riparian areas in agricultural watersheds.
We examined nine headwater streams with a gradient of riparian forest and agricultural land use t... more We examined nine headwater streams with a gradient of riparian forest and agricultural land use to determine the effect of riparian and watershed land use on stream communities. Sampling was conducted seasonally over three years to explore temporal patterns in macroinvertebrate and fish assemblages related to land use, in-stream habitat, and water quality parameters. While there were significant seasonal and annual differences, relationships among streams with different land use types were relatively consistent. Macroinvertebrate and fish abundance and biomass were significantly higher in streams with low percent riparian forest compared to streams with high percent riparian forest. Macroinvertebrate HBI and fish IBI scores improved with increasing percent riparian forest suggesting better stream water quality with increasing forest buffer. Streams with the highest percent forest buffer and lowest percent watershed agriculture had the highest biotic integrity, greatest abundance of ...
We examined nine headwater streams with a gradient of riparian forest and watershed agriculture t... more We examined nine headwater streams with a gradient of riparian forest and watershed agriculture to determine the extent to which riparian buffers can mitigate the effects of agricultural activities on stream ecosystems. Sampling was conducted seasonally over two years to explore temporal patterns in fish assemblages related to land use, in-stream habitat, and water quality parameters. Stable isotopes analysis (δ13C and δ15N) was performed to determine how land use and seasonal changes affect energy flow and in-stream food web structure. Results suggest significant community-wide isotopic shifts occurred among streams and seasons. Agricultural streams with low percent forest buffer had compressed food webs based primarily on periphytic energy sources with shorter food chain length compared to forested streams. Streams with high percent riparian forest had higher variability in δ13C than low forest buffer streams, suggesting consumers utilized a greater variety of carbon sources and i...
We examined nine headwater streams with a gradient of riparian forest buffer and watershed agricu... more We examined nine headwater streams with a gradient of riparian forest buffer and watershed agriculture to determine the extent to which riparian buffers can ameliorate the effects of agricultural activities on stream ecosystems. Sampling was conducted seasonally over three years to explore temporal patterns in macroinvertebrate and fish assemblages related to land use, in-stream habitat, and water quality parameters. Streams with low percent forest buffer had significantly higher daily maximum temperature, nitrate-nitrogen levels, and primary productivity than high forest buffer streams. Although there were greater abundances and biomass of macroinvertebrates and fish in streams with low forest buffer, assemblages were dominated by pollution tolerant taxa. Streams with high percent forest buffer and low watershed agriculture had the best biotic integrity and the most complex trophic structure. Ordinations based on fish assemblages indicated that streams sites grouped by land use cat...
ABSTRACT Crustacean zooplankton exhibit a variety of defenses which deter predation by gape-limit... more ABSTRACT Crustacean zooplankton exhibit a variety of defenses which deter predation by gape-limited (e.g., planktivorous fish) and size-dependent (e.g., invertebrate) predators. Cyclomorphic changes in morphology of a prey item, such as production of head and tail spines, presumably decrease the likelihood of capture and consumption by either class of predator. Daphnia lumholtzi exhibits extreme cyclomorphic features throughout its life history. We investigated the vulnerabilities of different size classes of D. lumholtzi and the non-spined Daphnia pulex to the invertebrate predator Leptodora kindti. In trials with single prey species, L. kindti consumed D. lumholtzi neonates at a higher rate than D. pulex neonates, medium D. pulex, and large D. pulex. When the daphnids were offered together in equal numbers, L. kindti selected D. lumholtzi at a faster rate than D. pulex in all size classes. Our results suggest that instead of providing protection, D. lumholzi's helmet and tail spine may increase likelihood of detection and capture by L. kindti, while decreasing the probability of escape.
It is critical for fisheries ecologists to evaluate physiological responses to understand how fis... more It is critical for fisheries ecologists to evaluate physiological responses to understand how fish cope with anthropogenic disturbances that have the potential to cause population declines. Few studies have quantified the underlying physiological mechanisms that dictate the ability of fish to cope with human disturbance. The purpose of this study was to quantify the influence of watershed and segment-scale land-use disturbance on the physiological responses of stream fish. To test this, Creek chub were collected from replicated agricultural (disturbed) and forested (control) streams and subjected to heat and hypoxia stressors to evaluate blood and whole animal physiological responses. No differences in baseline physiological parameters were found in fish sampled immediately from streams within forested or agricultural streams at either scale. However, when exposed to low oxygen conditions in the lab, creek chubs from forested watersheds had a higher stress response and greater ion l...
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