Derrick Klimesh, Adrienne V. Gossman, Y. Jun Xu, M. Kaller
Abstract Forests are the most dominant land-use type in Louisiana, and timber harvesting is the most economically important of the state’s agricultural commodities. Louisiana has developed voluntary best management practices (BMPs) to minimize negative effects of forest operations on stream water quality, but little is known about how aquatic communities inhabiting low-gradient, headwater streams respond to timber harvesting, and if the current BMPs are effective in protecting community structure and function. In 2005, we initiated a multidisciplinary study in the Flat Creek watershed in central Louisiana to discern the effects of timber harvesting activities, with and without BMP implementation, on benthic aquatic macroinvertebrates. During fall 2007, trees were removed adjacent to two headwater streams in the watershed, and benthic macroinvertebrate samples were subsequently collected at seven stream locations seven times between 2006 and 2009. Our objectives were to describe the community structure of benthic macroinvertebrates in low-order, low-gradient streams, how macroinvertebrate communities responded to timber harvest operations, and whether significant changes in community structure were evident under different levels of BMP implementation. The community structure was predominantly generalist taxa including chironomids, sphaeriid bivalves and asellid isopods. Analyses of variance demonstrated significant increases in bivalve abundance and decreases in the abundance of malacostracan and shredding taxa at most of the sampling sites downstream of BMP-implemented harvest locations in the spring. Additionally, significant increases in bivalves were also found at two sites during late summer. Our results suggest that timber harvesting activities, regardless of BMP implementation, had limited shortterm impacts on resident macroinvertebrates in these lowgradient, subtropical streams. Continued monitoring at the study sites will allow us to better understand the longterm effects of timber harvesting in these stream systems, particularly the resilience of stream biota to harvestingrelated stream conditions.
{"title":"Responses of stream benthic macroinvertebrate communities to timber harvesting: Best management practices in a low-gradient watershed in Central Louisiana, USA","authors":"Derrick Klimesh, Adrienne V. Gossman, Y. Jun Xu, M. Kaller","doi":"10.1515/remc-2015-0003","DOIUrl":"https://doi.org/10.1515/remc-2015-0003","url":null,"abstract":"Abstract Forests are the most dominant land-use type in Louisiana, and timber harvesting is the most economically important of the state’s agricultural commodities. Louisiana has developed voluntary best management practices (BMPs) to minimize negative effects of forest operations on stream water quality, but little is known about how aquatic communities inhabiting low-gradient, headwater streams respond to timber harvesting, and if the current BMPs are effective in protecting community structure and function. In 2005, we initiated a multidisciplinary study in the Flat Creek watershed in central Louisiana to discern the effects of timber harvesting activities, with and without BMP implementation, on benthic aquatic macroinvertebrates. During fall 2007, trees were removed adjacent to two headwater streams in the watershed, and benthic macroinvertebrate samples were subsequently collected at seven stream locations seven times between 2006 and 2009. Our objectives were to describe the community structure of benthic macroinvertebrates in low-order, low-gradient streams, how macroinvertebrate communities responded to timber harvest operations, and whether significant changes in community structure were evident under different levels of BMP implementation. The community structure was predominantly generalist taxa including chironomids, sphaeriid bivalves and asellid isopods. Analyses of variance demonstrated significant increases in bivalve abundance and decreases in the abundance of malacostracan and shredding taxa at most of the sampling sites downstream of BMP-implemented harvest locations in the spring. Additionally, significant increases in bivalves were also found at two sites during late summer. Our results suggest that timber harvesting activities, regardless of BMP implementation, had limited shortterm impacts on resident macroinvertebrates in these lowgradient, subtropical streams. Continued monitoring at the study sites will allow us to better understand the longterm effects of timber harvesting in these stream systems, particularly the resilience of stream biota to harvestingrelated stream conditions.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117187008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Salicaceae are typical invaders of riparian ecosystems throughout the world and they have the potential to change much of the invaded habitats. Along Patagonian streams, riparian softwood forests composed of non-native Salicaceae are increasing in abundance, area and tree species diversity. Especially in the last decades, dense floodplain forests dominated by invasive willows and poplars and additionally Russian olive and tamarisk spread almost explosively e.g. along the Río Negro in northern Patagonia. This study focuses on the identification of ecological niches and niche overlaps of the native and invasive woody species in order to assess the impact on the native Salix humboldtiana Willd. Data on species (presence/ absence) and explanatory variables were gathered in the field using a grid-based, stratified-randomized sampling design. Different environmental variables were then related to species occurrence in different life stages (adult, juvenile, seedling) using habitat distribution models. In the final models, flood duration, the amount of gravel and the location (upper or middle river valley) were included to describe the probability of occurrence of native and invasive taxa. For all life stages, a strong niche overlap could be observed for S. humboldtiana and the invasive taxa with no remaining exclusive habitats indicating a potential threat to the native willow. The study contributes to a better understanding of Salicaceae invasion and its consequences for riparian ecosystems.
{"title":"River dynamics and invasion: distribution patterns of native and invasive woody vegetation at the Río Negro, Argentina","authors":"L. K. Thomas, E. Mosner, Ilona Leyer","doi":"10.1515/remc-2015-0001","DOIUrl":"https://doi.org/10.1515/remc-2015-0001","url":null,"abstract":"Abstract Salicaceae are typical invaders of riparian ecosystems throughout the world and they have the potential to change much of the invaded habitats. Along Patagonian streams, riparian softwood forests composed of non-native Salicaceae are increasing in abundance, area and tree species diversity. Especially in the last decades, dense floodplain forests dominated by invasive willows and poplars and additionally Russian olive and tamarisk spread almost explosively e.g. along the Río Negro in northern Patagonia. This study focuses on the identification of ecological niches and niche overlaps of the native and invasive woody species in order to assess the impact on the native Salix humboldtiana Willd. Data on species (presence/ absence) and explanatory variables were gathered in the field using a grid-based, stratified-randomized sampling design. Different environmental variables were then related to species occurrence in different life stages (adult, juvenile, seedling) using habitat distribution models. In the final models, flood duration, the amount of gravel and the location (upper or middle river valley) were included to describe the probability of occurrence of native and invasive taxa. For all life stages, a strong niche overlap could be observed for S. humboldtiana and the invasive taxa with no remaining exclusive habitats indicating a potential threat to the native willow. The study contributes to a better understanding of Salicaceae invasion and its consequences for riparian ecosystems.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131006347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Grass filter strips are strips of cool or warm season grasses planted adjacent to agricultural streams to reduce nutrient, pesticide, and sediment input. This conservation practice is the most frequently planted riparian buffer type in the United States. Previous studies have not evaluated how grass filter strips alter the structure and function of riparian habitats of agricultural streams. Our objective was to examine the research hypothesis that planting grass filter strips will influence the structure and function of riparian habitats of channelized agricultural headwater streams. We sampled riparian vegetation, quantified coarse particulate organic matter input and nutrient input, and measured water temperature within two unplanted riparian habitat sites, two riparian habitat with grass filter strips sites, and two forested riparian habitat sites of agricultural headwater streams in central Ohio. Forested riparian habitats exhibited greater percent maximum frequency of woody vegetation and reduced water temperatures than unplanted riparian habitats and grass filter strips. Forested riparian habitats also exhibited greater canopy cover, woody vegetation taxa richness, and coarse particulate organic matter input than grass filter strips and greater riparian widths and woody vegetation abundance than unplanted riparian habitats. Grass filter strips did not differ in structure and function from unplanted riparian habitats. We conclude that planting grass filter strips does not influence the structure and function of riparian habitats of channelized agricultural headwater streams.
{"title":"Planting grass filter strips: Does it influence the structure and function of riparian habitats of agricultural headwater streams?","authors":"Peter C. Smiley Jr., K. Rumora","doi":"10.1515/remc-2015-0002","DOIUrl":"https://doi.org/10.1515/remc-2015-0002","url":null,"abstract":"Abstract Grass filter strips are strips of cool or warm season grasses planted adjacent to agricultural streams to reduce nutrient, pesticide, and sediment input. This conservation practice is the most frequently planted riparian buffer type in the United States. Previous studies have not evaluated how grass filter strips alter the structure and function of riparian habitats of agricultural streams. Our objective was to examine the research hypothesis that planting grass filter strips will influence the structure and function of riparian habitats of channelized agricultural headwater streams. We sampled riparian vegetation, quantified coarse particulate organic matter input and nutrient input, and measured water temperature within two unplanted riparian habitat sites, two riparian habitat with grass filter strips sites, and two forested riparian habitat sites of agricultural headwater streams in central Ohio. Forested riparian habitats exhibited greater percent maximum frequency of woody vegetation and reduced water temperatures than unplanted riparian habitats and grass filter strips. Forested riparian habitats also exhibited greater canopy cover, woody vegetation taxa richness, and coarse particulate organic matter input than grass filter strips and greater riparian widths and woody vegetation abundance than unplanted riparian habitats. Grass filter strips did not differ in structure and function from unplanted riparian habitats. We conclude that planting grass filter strips does not influence the structure and function of riparian habitats of channelized agricultural headwater streams.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113956663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Close-range digital photography is a promising tool for monitoring plant communities, yet this technology has not been used to indicate changes to the compositional and functional characteristics of riparian vegetation buffers in agro-ecosystems. We tested a photographic protocol using image indices to monitor differences in the compositional (species diversity) and functional characteristics (plant height, flowering and leaf traits) of 28 herbaceous communities repeatedly surveyed over an entire growing season. Specifically, we used known vegetation properties to predict image texture and geometric patterns. Our results revealed that image texture decreased with increasing plant height, leaf polyphenol content and species diversity. Low texture values in close-range digital images were typically found in tall, flowering, and functionally diversified assemblages consisting mostly of forbs species. In contrast, species assemblages dominated by grasses or sedges presented more random geometric patterns and images with higher texture values. Further tests of this photographic protocol will have to explore other image indices and extend its application to other ecosystems.
{"title":"A digital photography protocol for the rapid assessment of herbaceous communities in riparian buffers","authors":"Laurianne Bonin, R. Proulx, G. Rheault","doi":"10.2478/remc-2014-0003","DOIUrl":"https://doi.org/10.2478/remc-2014-0003","url":null,"abstract":"Abstract Close-range digital photography is a promising tool for monitoring plant communities, yet this technology has not been used to indicate changes to the compositional and functional characteristics of riparian vegetation buffers in agro-ecosystems. We tested a photographic protocol using image indices to monitor differences in the compositional (species diversity) and functional characteristics (plant height, flowering and leaf traits) of 28 herbaceous communities repeatedly surveyed over an entire growing season. Specifically, we used known vegetation properties to predict image texture and geometric patterns. Our results revealed that image texture decreased with increasing plant height, leaf polyphenol content and species diversity. Low texture values in close-range digital images were typically found in tall, flowering, and functionally diversified assemblages consisting mostly of forbs species. In contrast, species assemblages dominated by grasses or sedges presented more random geometric patterns and images with higher texture values. Further tests of this photographic protocol will have to explore other image indices and extend its application to other ecosystems.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123184260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Karolina Stenroth, Trent M. Hoover, J. Herrmann, I. Bohman, J. Richardson
Abstract The food webs of forest streams are primarily based upon inputs of organic matter from adjacent terrestrial ecosystems. However, streams that run through open landscapes generally lack closed riparian canopies, and an increasing number of studies indicate that terrestrial organic matter may be an important resource in these systems as well. Combining key abiotically-controlled factors (stream discharge, water temperature, and litter input rate) with relevant biotic processes (e.g. macroinvertebrate CPOM consumption, microbial processing), we constructed a model to predict and contrast organic matter dynamics (including temporal variation in CPOM standing crop, CPOM processing rate, FPOM production, and detritivore biomass) in small riparian-forested and open-canopy streams. Our modeled results showed that the standing crop of CPOM was similar between riparian-forested and open-canopy streams, despite considerable differences in litter input rate. This unexpected result was partly due to linkages between CPOM supply and consumer abundance that produced higher detritivore biomass in the forest stream than the open-canopy stream. CPOM standing crop in the forest stream was mainly regulated by top-down consumer control, depressing it to a level similar to that of the open-canopy stream. In contrast, CPOM standing crop in the open-canopy stream was primarily controlled by physical factors (litter input rates and discharge), not consumption. This suggests that abiotic processes (e.g. discharge) may play a greater role in limiting detrital resource availability and consumer biomass in open-canopy streams than in forest streams. These model results give insight on functional differences that exists among streams and they can be used to predict effects of anthropogenic influences such as forestry, agriculture, urbanization, and climate change on streams and how riparian management and conservation tools can be employed to mitigate undesirable effects.
{"title":"A model-based comparison of organic matter dynamics between riparian-forested and open-canopy streams","authors":"Karolina Stenroth, Trent M. Hoover, J. Herrmann, I. Bohman, J. Richardson","doi":"10.2478/remc-2014-0001","DOIUrl":"https://doi.org/10.2478/remc-2014-0001","url":null,"abstract":"Abstract The food webs of forest streams are primarily based upon inputs of organic matter from adjacent terrestrial ecosystems. However, streams that run through open landscapes generally lack closed riparian canopies, and an increasing number of studies indicate that terrestrial organic matter may be an important resource in these systems as well. Combining key abiotically-controlled factors (stream discharge, water temperature, and litter input rate) with relevant biotic processes (e.g. macroinvertebrate CPOM consumption, microbial processing), we constructed a model to predict and contrast organic matter dynamics (including temporal variation in CPOM standing crop, CPOM processing rate, FPOM production, and detritivore biomass) in small riparian-forested and open-canopy streams. Our modeled results showed that the standing crop of CPOM was similar between riparian-forested and open-canopy streams, despite considerable differences in litter input rate. This unexpected result was partly due to linkages between CPOM supply and consumer abundance that produced higher detritivore biomass in the forest stream than the open-canopy stream. CPOM standing crop in the forest stream was mainly regulated by top-down consumer control, depressing it to a level similar to that of the open-canopy stream. In contrast, CPOM standing crop in the open-canopy stream was primarily controlled by physical factors (litter input rates and discharge), not consumption. This suggests that abiotic processes (e.g. discharge) may play a greater role in limiting detrital resource availability and consumer biomass in open-canopy streams than in forest streams. These model results give insight on functional differences that exists among streams and they can be used to predict effects of anthropogenic influences such as forestry, agriculture, urbanization, and climate change on streams and how riparian management and conservation tools can be employed to mitigate undesirable effects.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127944190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nate Hough-Snee, A. Kasprak, B. Roper, C. Meredith
Abstract Instream wood is a driver of geomorphic change in low-order streams, frequently altering morphodynamic processes. Instream wood is a frequently measured component of streams, yet it is a complex metric, responding to ecological and geomorphic forcings at a variety of scales. Here we seek to disentangle the relative importance of physical and biological processes that drive wood growth and delivery to streams across broad spatial extents. In so doing, we ask two primary questions: (1) is riparian vegetation a composite variable that captures the indirect effects of climate and disturbance on instream wood dynamics? (2) What are the direct and indirect relationships between geomorphic setting, vegetation, climate, disturbance, and instream wood dynamics? We measured riparian vegetation composition and wood frequency and volume at 720 headwater reaches within the American interior Pacific Northwest. We used ordination to identify relationships between vegetation and environmental attributes, and subsequently built a structural equation model to identify how climate and disturbance directly affect vegetation composition and how vegetation and geomorphic setting directly affect instream wood volume and frequency. We found that large wood volume and frequency are directly driven by vegetation composition and positively correlated to wildfire, elevation, stream gradient, and channel bankfull width. Indicator species at reaches with high volumes of wood were generally long-lived, conifer trees that persist for extended durations once delivered to stream habitats. Wood dynamics were also indirectly mediated by factors that shape vegetation: wildfire, precipitation, elevation, and temperature. We conclude that wood volume and frequency are driven by multiple interrelated climatic, geomorphic, and ecological variables. Vegetation composition and geomorphic setting directly mediate indirect relationships between landscape environmental processes and instream large wood. Where climate or geomorphic setting preclude tree establishment, reaches may remain naturally depauperate of instream wood unless wood is transported from elsewhere in the stream network.
{"title":"Direct and indirect drivers of instream wood in the interior Pacific Northwest, USA: decoupling climate, vegetation, disturbance, and geomorphic setting","authors":"Nate Hough-Snee, A. Kasprak, B. Roper, C. Meredith","doi":"10.2478/remc-2014-0002","DOIUrl":"https://doi.org/10.2478/remc-2014-0002","url":null,"abstract":"Abstract Instream wood is a driver of geomorphic change in low-order streams, frequently altering morphodynamic processes. Instream wood is a frequently measured component of streams, yet it is a complex metric, responding to ecological and geomorphic forcings at a variety of scales. Here we seek to disentangle the relative importance of physical and biological processes that drive wood growth and delivery to streams across broad spatial extents. In so doing, we ask two primary questions: (1) is riparian vegetation a composite variable that captures the indirect effects of climate and disturbance on instream wood dynamics? (2) What are the direct and indirect relationships between geomorphic setting, vegetation, climate, disturbance, and instream wood dynamics? We measured riparian vegetation composition and wood frequency and volume at 720 headwater reaches within the American interior Pacific Northwest. We used ordination to identify relationships between vegetation and environmental attributes, and subsequently built a structural equation model to identify how climate and disturbance directly affect vegetation composition and how vegetation and geomorphic setting directly affect instream wood volume and frequency. We found that large wood volume and frequency are directly driven by vegetation composition and positively correlated to wildfire, elevation, stream gradient, and channel bankfull width. Indicator species at reaches with high volumes of wood were generally long-lived, conifer trees that persist for extended durations once delivered to stream habitats. Wood dynamics were also indirectly mediated by factors that shape vegetation: wildfire, precipitation, elevation, and temperature. We conclude that wood volume and frequency are driven by multiple interrelated climatic, geomorphic, and ecological variables. Vegetation composition and geomorphic setting directly mediate indirect relationships between landscape environmental processes and instream large wood. Where climate or geomorphic setting preclude tree establishment, reaches may remain naturally depauperate of instream wood unless wood is transported from elsewhere in the stream network.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115025758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The aim of this study was to determine the sources of water uptake for two common riparian tree species found in the southeastern United States, Acer negundo and Betula nigra. The study site was located within a riparian zone typical of this region and those of the temperate USA. Water sources were determined by analyzing signatures of stable isotopes found naturally in water, 2H and 18O. Samples from surface water, groundwater, and soil, plus woody tissue from mature individuals of each species, were taken once each month during the 2011 summer growth season. Both species relied strongly on an unidentified ground water source, although A. negundo also showed a strong correlation with deep soil moisture (r2 = 0.972). Sampling limitations did not permit an accurate determination of the fractional contribution of each source to plant water, limiting the strength of the results. The evidence collected leads to conclusions comparable to those of studies that have been conducted in arid parts of North America, corroborating that streamside species may rely heavily on groundwater sources, not surface streamwater. Further studies are needed in this region to confirm the evidence reported here to establish a baseline for vegetation in these systems.
{"title":"Water sources in riparian trees of the southern Appalachian foothills, USA: A preliminary study with stable isotope analysis","authors":"Joseph C. White, W. K. Smith","doi":"10.2478/remc-2013-0006","DOIUrl":"https://doi.org/10.2478/remc-2013-0006","url":null,"abstract":"Abstract The aim of this study was to determine the sources of water uptake for two common riparian tree species found in the southeastern United States, Acer negundo and Betula nigra. The study site was located within a riparian zone typical of this region and those of the temperate USA. Water sources were determined by analyzing signatures of stable isotopes found naturally in water, 2H and 18O. Samples from surface water, groundwater, and soil, plus woody tissue from mature individuals of each species, were taken once each month during the 2011 summer growth season. Both species relied strongly on an unidentified ground water source, although A. negundo also showed a strong correlation with deep soil moisture (r2 = 0.972). Sampling limitations did not permit an accurate determination of the fractional contribution of each source to plant water, limiting the strength of the results. The evidence collected leads to conclusions comparable to those of studies that have been conducted in arid parts of North America, corroborating that streamside species may rely heavily on groundwater sources, not surface streamwater. Further studies are needed in this region to confirm the evidence reported here to establish a baseline for vegetation in these systems.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127053217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The central reach of the Ebro River, one of the largest rivers in the Mediterranean region, is characterised by a meandering channel that develops into a wide floodplain. In the present study, we analysed the evolution of the landscape structure and function of riparian forests in the Middle Ebro River (~ 250 km long) in 1927, 1957 and 2003 in order to evaluate the forest dynamics in this river corridor. In the 20th century, the Ebro floodplain suffered a dramatic hydromorphological transformation as a result of urban and agricultural encroachment on the river territory and modifications to its flow regime. This study assesses the overall morphology and connectivity of riparian forest patches in the study area using a wide range of parameters. The influence of the hydromorphological changes of the river system on the general status of the riparian forests was then determined. The analysis revealed a profound trend toward the homogenisation and isolation of forest patches. Habitat loss and landscape fragmentation were the dominant processes in the study area and were especially intense in some river segments, where large forest patches and high connectivity once prevailed. Landscape modification and overall homogenisation intensified during the second half of the last century. The results for the entire set of parameters can be used to identify guidelines for the effective attenuation of these trends and for the progressive rehabilitation of the dynamics of the Middle Ebro landscape.
{"title":"Evolution of the Riparian Forest Corridor in a Large Mediterranean River System","authors":"F. Magdaleno, J. A. Fernández-Yuste","doi":"10.2478/remc-2013-0005","DOIUrl":"https://doi.org/10.2478/remc-2013-0005","url":null,"abstract":"Abstract The central reach of the Ebro River, one of the largest rivers in the Mediterranean region, is characterised by a meandering channel that develops into a wide floodplain. In the present study, we analysed the evolution of the landscape structure and function of riparian forests in the Middle Ebro River (~ 250 km long) in 1927, 1957 and 2003 in order to evaluate the forest dynamics in this river corridor. In the 20th century, the Ebro floodplain suffered a dramatic hydromorphological transformation as a result of urban and agricultural encroachment on the river territory and modifications to its flow regime. This study assesses the overall morphology and connectivity of riparian forest patches in the study area using a wide range of parameters. The influence of the hydromorphological changes of the river system on the general status of the riparian forests was then determined. The analysis revealed a profound trend toward the homogenisation and isolation of forest patches. Habitat loss and landscape fragmentation were the dominant processes in the study area and were especially intense in some river segments, where large forest patches and high connectivity once prevailed. Landscape modification and overall homogenisation intensified during the second half of the last century. The results for the entire set of parameters can be used to identify guidelines for the effective attenuation of these trends and for the progressive rehabilitation of the dynamics of the Middle Ebro landscape.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"278 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125854345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Van Looy, Cyril Cavillon, T. Tormos, J. Piffady, P. Landry, Y. Souchon
Abstract The well-documented re-colonisation of the French large river basins of Loire and Rhone by European otter and beaver allowed the analysis of explanatory factors and threats to species movement in the river corridor. To what extent anthropogenic disturbance of the riparian zone influences the corridor functioning is a central question in the understanding of ecological networks and the definition of restoration goals for river networks. The generalist or specialist nature of target species might be determining for the responses to habitat quality and barriers in the riparian corridor. Detailed datasets of land use, human stressors and hydro-morphological characteristics of river segments for the entire river basins allowed identifying the habitat requirements of the two species for the riparian zone. The identified critical factors were entered in a network analysis based on the ecological niche factor approach. Significant responses to riparian corridor quality for forest cover, alterations of channel straightening and urbanisation and infrastructure in the riparian zone are observed for both species, so they may well serve as indicators for corridor functioning. The hypothesis for generalists being less sensitive to human disturbance was withdrawn, since the otter as generalist species responded strongest to hydro-morphological alterations and human presence in general. The beaver responded the strongest to the physical environment as expected for this specialist species. The difference in responses for generalist and specialist species is clearly present and the two species have a strong complementary indicator value. The interpretation of the network analysis outcomes stresses the need for an estimation of ecological requirements of more species in the evaluation of riparian corridor functioning and in conservation planning.
{"title":"Are generalist and specialist species influenced differently by anthropogenic stressors and physical environment of riparian corridors?","authors":"K. Van Looy, Cyril Cavillon, T. Tormos, J. Piffady, P. Landry, Y. Souchon","doi":"10.2478/remc-2013-0004","DOIUrl":"https://doi.org/10.2478/remc-2013-0004","url":null,"abstract":"Abstract The well-documented re-colonisation of the French large river basins of Loire and Rhone by European otter and beaver allowed the analysis of explanatory factors and threats to species movement in the river corridor. To what extent anthropogenic disturbance of the riparian zone influences the corridor functioning is a central question in the understanding of ecological networks and the definition of restoration goals for river networks. The generalist or specialist nature of target species might be determining for the responses to habitat quality and barriers in the riparian corridor. Detailed datasets of land use, human stressors and hydro-morphological characteristics of river segments for the entire river basins allowed identifying the habitat requirements of the two species for the riparian zone. The identified critical factors were entered in a network analysis based on the ecological niche factor approach. Significant responses to riparian corridor quality for forest cover, alterations of channel straightening and urbanisation and infrastructure in the riparian zone are observed for both species, so they may well serve as indicators for corridor functioning. The hypothesis for generalists being less sensitive to human disturbance was withdrawn, since the otter as generalist species responded strongest to hydro-morphological alterations and human presence in general. The beaver responded the strongest to the physical environment as expected for this specialist species. The difference in responses for generalist and specialist species is clearly present and the two species have a strong complementary indicator value. The interpretation of the network analysis outcomes stresses the need for an estimation of ecological requirements of more species in the evaluation of riparian corridor functioning and in conservation planning.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"93 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113954371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lizhu Wang, Travis O. Brenden, J. Lyons, D. Infante
Abstract Quantifying spatial patterns of physical and biological features is essential for managing aquatic systems. To meet broad-scale habitat assessment and monitoring needs, we evaluated the feasibility of predicting 25 instream physical habitat measures for wadeable stream reaches in Wisconsin and northern Michigan using geographic information system (GIS) derived stream network and landscape data. Using general additive modeling and boosting variable selection, predictions of reasonable accuracy were obtained for 10 widely used in-stream habitat measures, including bankfull depth and width, conductivity, substrate size, sand substrate, thalweg water depth, wetted width, water depth, and widthto- depth ratio. Biased predictions were obtained for habitat measures such as bank erosion, large woody debris, fish cover, canopy shading, and substrate embeddedness. Model predictions for many commonlyused habitat variables were judged acceptable based on several criteria, including correspondence between prediction errors and observed interannual and inter-site variability in habitat measures and agreement in correlation analyses of fish assemblage metric data with both predicted and observed values. Prediction of physical habitat variables from widely available GIS datasets represents a potentially powerful and cost-effective approach for broad-scale (e.g., multi-state, national) assessment and monitoring of in-stream conditions, for which direct measurement is largely impractical because of resource limitations.
{"title":"Predictability of In-Stream Physical Habitat for Wisconsin and Northern Michigan Wadeable Streams Using GIS-Derived Landscape Data","authors":"Lizhu Wang, Travis O. Brenden, J. Lyons, D. Infante","doi":"10.2478/remc-2013-0003","DOIUrl":"https://doi.org/10.2478/remc-2013-0003","url":null,"abstract":"Abstract Quantifying spatial patterns of physical and biological features is essential for managing aquatic systems. To meet broad-scale habitat assessment and monitoring needs, we evaluated the feasibility of predicting 25 instream physical habitat measures for wadeable stream reaches in Wisconsin and northern Michigan using geographic information system (GIS) derived stream network and landscape data. Using general additive modeling and boosting variable selection, predictions of reasonable accuracy were obtained for 10 widely used in-stream habitat measures, including bankfull depth and width, conductivity, substrate size, sand substrate, thalweg water depth, wetted width, water depth, and widthto- depth ratio. Biased predictions were obtained for habitat measures such as bank erosion, large woody debris, fish cover, canopy shading, and substrate embeddedness. Model predictions for many commonlyused habitat variables were judged acceptable based on several criteria, including correspondence between prediction errors and observed interannual and inter-site variability in habitat measures and agreement in correlation analyses of fish assemblage metric data with both predicted and observed values. Prediction of physical habitat variables from widely available GIS datasets represents a potentially powerful and cost-effective approach for broad-scale (e.g., multi-state, national) assessment and monitoring of in-stream conditions, for which direct measurement is largely impractical because of resource limitations.","PeriodicalId":347139,"journal":{"name":"Riparian Ecology and Conservation","volume":"12 1-4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120962607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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