Abstract Southern Florida's Everglades are at the front line of potential negative effects on aquatic ecosystems from climate change and associated sea-level rise. A diversity of aquatic habitats supports a rich assemblage of aquatic and terrestrial wildlife, including 36 vertebrates and 26 plant species federally listed as endangered, threatened, or candidate species. Anticipated climate-change trends for southern Florida include increased weather uncertainty with more droughts, higher temperatures, and an increased number of more intense storms. Hydrologic regimes, temperature, and CO2 have been strongly correlated with plant community structure, coral and fish abundance and diversity, and higher trophic-level responses. Higher levels of variability in extreme climatic events, such as droughts, have the potential to destabilize aquatic communities. Sea-level rise is expected to be 0.8 to 2 m over the next century, a serious problem in a landscape that rises only 5 cm/km from Florida Bay inland. Wading birds and other wildlife species dependent on fresh water are likely to decline because of salt-water overwash and inundation. In addition to causing habitat loss, saltwater inundation of the peat substrate of Everglades freshwater wetlands may increase C emissions from sequestered C released as peat is destroyed and freshwater plant communities die. Identification of those species and habitats most at risk and ways to increase habitat and landscape resilience to large-scale environmental change will be critical for maintaining a diverse and productive Everglades.
{"title":"A review of the ecological consequences and management implications of climate change for the Everglades","authors":"L. Pearlstine, E. V. Pearlstine, N. Aumen","doi":"10.1899/10-045.1","DOIUrl":"https://doi.org/10.1899/10-045.1","url":null,"abstract":"Abstract Southern Florida's Everglades are at the front line of potential negative effects on aquatic ecosystems from climate change and associated sea-level rise. A diversity of aquatic habitats supports a rich assemblage of aquatic and terrestrial wildlife, including 36 vertebrates and 26 plant species federally listed as endangered, threatened, or candidate species. Anticipated climate-change trends for southern Florida include increased weather uncertainty with more droughts, higher temperatures, and an increased number of more intense storms. Hydrologic regimes, temperature, and CO2 have been strongly correlated with plant community structure, coral and fish abundance and diversity, and higher trophic-level responses. Higher levels of variability in extreme climatic events, such as droughts, have the potential to destabilize aquatic communities. Sea-level rise is expected to be 0.8 to 2 m over the next century, a serious problem in a landscape that rises only 5 cm/km from Florida Bay inland. Wading birds and other wildlife species dependent on fresh water are likely to decline because of salt-water overwash and inundation. In addition to causing habitat loss, saltwater inundation of the peat substrate of Everglades freshwater wetlands may increase C emissions from sequestered C released as peat is destroyed and freshwater plant communities die. Identification of those species and habitats most at risk and ways to increase habitat and landscape resilience to large-scale environmental change will be critical for maintaining a diverse and productive Everglades.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"131 1","pages":"1510 - 1526"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90829555","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}
L. Poff, Matthew I. Pyne, Brian P. Bledsoe, Christopher C. Cuhaciyan, D. Carlisle
Abstract Forecasting responses of benthic community structure and function to anthropogenic climate change is an emerging scientific challenge. Characterizing benthic species by biological attributes (traits) that are responsive to temperature and streamflow conditions can support a mechanistic approach for assessing the potential ecological responses to climate change. However, nonclimatic environmental factors also structure benthic communities and may mitigate transient climatic conditions, and these must be considered in evaluating potential impacts of climate change. Here we used macroinvertebrate and environmental data for 279 reference-quality sites spanning 12 states in the western US. For each sampling location, we described 45 environmental variables that spanned reach to catchment scales and that represented contemporary climate drivers, hydrologic metrics, and nonclimatic habitat features, as well as purely spatial metrics. We described benthic community composition at each site in terms of 7 species traits, including those considered sensitive to temperature increases and streamflow changes. All combined environmental variables explained 67% of the total trait variation across the sites, and catchment-scale climatic and hydrologic variables independently accounted for 19%. Sites were clustered into 3 community types based on trait composition, and a classification-tree analysis confirmed that climatic and hydrologic variables were important in partitioning these groups. Sensitivity of benthic communities to projected climate change was assessed by quantifying the proportion of taxa at sites having the traits of either cold stenothermy or obligate rheophily. Regression-tree analysis showed that temperature and hydrologic variables mostly accounted for the differences in proportion of sensitivity traits across the sites. We examined the vulnerability of sites to climate change by superimposing regional-scale projections of late-21st-century temperature and runoff change on the spatial distribution of temperature- and runoff-sensitive assemblages. Sites with high proportions of cold stenotherms and obligate rheophiles occur throughout the western US, but the degree of temperature and runoff change is projected to be greatest for reference sites in the Upper Colorado River and Great Basin. Thus, our results suggest that traits-based sensitivity coupled with intraregional variation in projected changes in temperature and runoff will cause reference sites in the western US to be differentially vulnerable to future climate change.
{"title":"Developing linkages between species traits and multiscaled environmental variation to explore vulnerability of stream benthic communities to climate change","authors":"L. Poff, Matthew I. Pyne, Brian P. Bledsoe, Christopher C. Cuhaciyan, D. Carlisle","doi":"10.1899/10-030.1","DOIUrl":"https://doi.org/10.1899/10-030.1","url":null,"abstract":"Abstract Forecasting responses of benthic community structure and function to anthropogenic climate change is an emerging scientific challenge. Characterizing benthic species by biological attributes (traits) that are responsive to temperature and streamflow conditions can support a mechanistic approach for assessing the potential ecological responses to climate change. However, nonclimatic environmental factors also structure benthic communities and may mitigate transient climatic conditions, and these must be considered in evaluating potential impacts of climate change. Here we used macroinvertebrate and environmental data for 279 reference-quality sites spanning 12 states in the western US. For each sampling location, we described 45 environmental variables that spanned reach to catchment scales and that represented contemporary climate drivers, hydrologic metrics, and nonclimatic habitat features, as well as purely spatial metrics. We described benthic community composition at each site in terms of 7 species traits, including those considered sensitive to temperature increases and streamflow changes. All combined environmental variables explained 67% of the total trait variation across the sites, and catchment-scale climatic and hydrologic variables independently accounted for 19%. Sites were clustered into 3 community types based on trait composition, and a classification-tree analysis confirmed that climatic and hydrologic variables were important in partitioning these groups. Sensitivity of benthic communities to projected climate change was assessed by quantifying the proportion of taxa at sites having the traits of either cold stenothermy or obligate rheophily. Regression-tree analysis showed that temperature and hydrologic variables mostly accounted for the differences in proportion of sensitivity traits across the sites. We examined the vulnerability of sites to climate change by superimposing regional-scale projections of late-21st-century temperature and runoff change on the spatial distribution of temperature- and runoff-sensitive assemblages. Sites with high proportions of cold stenotherms and obligate rheophiles occur throughout the western US, but the degree of temperature and runoff change is projected to be greatest for reference sites in the Upper Colorado River and Great Basin. Thus, our results suggest that traits-based sensitivity coupled with intraregional variation in projected changes in temperature and runoff will cause reference sites in the western US to be differentially vulnerable to future climate change.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"139-140 1","pages":"1441 - 1458"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73218741","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 Phytoplankton and littoral invertebrate assemblages in 4 boreal lakes recovering from acidification and 4 minimally disturbed reference lakes studied over 2 decades were used to determine the pathways and trajectories of change under the influence of climatic variability. Assemblage composition (species presence–absence data) but not dominance patterns (invertebrate abundance/phytoplankton biovolume) of acidified lakes became more similar to those of reference lakes (distance decreased with time), indicating that detection of recovery varies as a function of chosen metrics. Acidified lakes had more pronounced shifts in assemblage composition than did reference lakes. The most marked differences were noted for phytoplankton assemblages. Assemblages in acidified lakes had mean between-year Euclidean distances almost 2× greater than those of assemblages in reference lakes. Trends in water chemistry showed unequivocal recovery, but responses of phytoplankton and invertebrate assemblages, measured as between-year shifts in assemblage composition, were correlated with interannual variability in climate (e.g., North Atlantic Oscillation, water temperature) in addition to decreased acidity. The finding that recovery pathways and trajectories of individual acidified lakes and the environmental drivers explaining these changes differed among assemblages shows that biological recovery is complex and the influence of climatic variability is poorly understood.
{"title":"Tracing recovery under changing climate: response of phytoplankton and invertebrate assemblages to decreased acidification","authors":"Richard K. Johnson, D. Angeler","doi":"10.1899/09-171.1","DOIUrl":"https://doi.org/10.1899/09-171.1","url":null,"abstract":"Abstract Phytoplankton and littoral invertebrate assemblages in 4 boreal lakes recovering from acidification and 4 minimally disturbed reference lakes studied over 2 decades were used to determine the pathways and trajectories of change under the influence of climatic variability. Assemblage composition (species presence–absence data) but not dominance patterns (invertebrate abundance/phytoplankton biovolume) of acidified lakes became more similar to those of reference lakes (distance decreased with time), indicating that detection of recovery varies as a function of chosen metrics. Acidified lakes had more pronounced shifts in assemblage composition than did reference lakes. The most marked differences were noted for phytoplankton assemblages. Assemblages in acidified lakes had mean between-year Euclidean distances almost 2× greater than those of assemblages in reference lakes. Trends in water chemistry showed unequivocal recovery, but responses of phytoplankton and invertebrate assemblages, measured as between-year shifts in assemblage composition, were correlated with interannual variability in climate (e.g., North Atlantic Oscillation, water temperature) in addition to decreased acidity. The finding that recovery pathways and trajectories of individual acidified lakes and the environmental drivers explaining these changes differed among assemblages shows that biological recovery is complex and the influence of climatic variability is poorly understood.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"5 1","pages":"1472 - 1490"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78499793","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}
J. Lawrence, Kevin B. Lunde, R. Mazor, L. Bêche, E. P. McElravy, V. Resh
Abstract Climate change is expected to have strong effects on mediterranean-climate regions worldwide. In some areas, these effects will include increases in temperature and decreases in rainfall, which could have important implications for biological assessment programs of aquatic ecosystems. We used a consistently collected, 20-y benthic macroinvertebrate data set from 4 sites along 2 small northern California streams to examine potential climate-change effects on aquatic communities. The sites represented unique combinations of stream order and flow intermittency. The North Coast benthic macroinvertebrate index of biotic integrity (B-IBI) developed for northern California streams was not influenced by temperature extremes (cool and warm) or precipitation extremes (wet and dry). Other common indices and metrics used in biological monitoring studies, such as the ratio of observed to expected taxa (O/E), % Ephemeroptera, Plecoptera, and Trichoptera (EPT) individuals, and total richness were unaffected by temperature and precipitation variability. For future monitoring of climate-change effects on small streams, we developed a local climate-change indicator that is composed of the presence/absence of 9 macroinvertebrate taxa, identified to genus level. This indicator detected significant differences between years that were grouped based on temperature, precipitation, and a combination of temperature and precipitation. It also detected significant differences between groups in an external data set including 40 reference sites throughout the San Francisco Bay area, a result that suggests this indicator could be used at larger spatial scales in this region. Two biological trait categories found in large, long-lived organisms decreased with increasing temperature and decreasing precipitation at the most intermittent site. This result indicates that climate change might selectively affect taxa with certain traits. The robustness of the North Coast B-IBI and other common indices and metrics to temperature and precipitation variability demonstrates their continued applicability for examining water quality under future climate-change scenarios, but suggests that they probably will not be good indicators for detecting climate-change effects. The effects of climate change in mediterranean-climate streams can be monitored effectively within the framework of existing biological assessment programs by using regional indicators based on specific taxa identified to the generic level and information on their species traits.
{"title":"Long-term macroinvertebrate responses to climate change: implications for biological assessment in mediterranean-climate streams","authors":"J. Lawrence, Kevin B. Lunde, R. Mazor, L. Bêche, E. P. McElravy, V. Resh","doi":"10.1899/09-178.1","DOIUrl":"https://doi.org/10.1899/09-178.1","url":null,"abstract":"Abstract Climate change is expected to have strong effects on mediterranean-climate regions worldwide. In some areas, these effects will include increases in temperature and decreases in rainfall, which could have important implications for biological assessment programs of aquatic ecosystems. We used a consistently collected, 20-y benthic macroinvertebrate data set from 4 sites along 2 small northern California streams to examine potential climate-change effects on aquatic communities. The sites represented unique combinations of stream order and flow intermittency. The North Coast benthic macroinvertebrate index of biotic integrity (B-IBI) developed for northern California streams was not influenced by temperature extremes (cool and warm) or precipitation extremes (wet and dry). Other common indices and metrics used in biological monitoring studies, such as the ratio of observed to expected taxa (O/E), % Ephemeroptera, Plecoptera, and Trichoptera (EPT) individuals, and total richness were unaffected by temperature and precipitation variability. For future monitoring of climate-change effects on small streams, we developed a local climate-change indicator that is composed of the presence/absence of 9 macroinvertebrate taxa, identified to genus level. This indicator detected significant differences between years that were grouped based on temperature, precipitation, and a combination of temperature and precipitation. It also detected significant differences between groups in an external data set including 40 reference sites throughout the San Francisco Bay area, a result that suggests this indicator could be used at larger spatial scales in this region. Two biological trait categories found in large, long-lived organisms decreased with increasing temperature and decreasing precipitation at the most intermittent site. This result indicates that climate change might selectively affect taxa with certain traits. The robustness of the North Coast B-IBI and other common indices and metrics to temperature and precipitation variability demonstrates their continued applicability for examining water quality under future climate-change scenarios, but suggests that they probably will not be good indicators for detecting climate-change effects. The effects of climate change in mediterranean-climate streams can be monitored effectively within the framework of existing biological assessment programs by using regional indicators based on specific taxa identified to the generic level and information on their species traits.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"16 1","pages":"1424 - 1440"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81774679","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}
Jen Stamp, Anna T. Hamilton, Lei Zheng, B. Bierwagen
Abstract Analyses of long-term data are an important component of climate-change research because they can help further our understanding of the effects of climate change and can help establish expectations for biological responses to future climate changes. We used macroinvertebrate data to assess whether biological trends associated with directional climate change could be detected in routine biomonitoring data from Maine, North Carolina, and Utah. We analyzed data from 8 long-term biomonitoring sites that had 9 to 22 y of data, and focused on thermal-preference metrics based on cold- and warm-water-preference trait groups. The thermal-preference metrics were derived primarily from weighted-average or generalized-linear-model inferences based on data from each state database and are region specific. Long-term trends varied across sites and regions. At some sites, the thermal-preference metrics showed significant patterns that could be interpreted as being related to directional climate change, whereas at others, patterns were not as expected or were not evident. The strongest trends occurred at 2 Utah sites that had ≥14 y of data. At these sites, cold-water taxa were negatively correlated with air temperature, and, when years were grouped into hottest- and coldest-year samples, were strongly reduced in the hottest-year samples. Results suggest that thermal-preference metrics show promise for application in a biomonitoring context to differentiate climate-related responses from other stressors.
{"title":"Use of thermal preference metrics to examine state biomonitoring data for climate change effects","authors":"Jen Stamp, Anna T. Hamilton, Lei Zheng, B. Bierwagen","doi":"10.1899/10-003.1","DOIUrl":"https://doi.org/10.1899/10-003.1","url":null,"abstract":"Abstract Analyses of long-term data are an important component of climate-change research because they can help further our understanding of the effects of climate change and can help establish expectations for biological responses to future climate changes. We used macroinvertebrate data to assess whether biological trends associated with directional climate change could be detected in routine biomonitoring data from Maine, North Carolina, and Utah. We analyzed data from 8 long-term biomonitoring sites that had 9 to 22 y of data, and focused on thermal-preference metrics based on cold- and warm-water-preference trait groups. The thermal-preference metrics were derived primarily from weighted-average or generalized-linear-model inferences based on data from each state database and are region specific. Long-term trends varied across sites and regions. At some sites, the thermal-preference metrics showed significant patterns that could be interpreted as being related to directional climate change, whereas at others, patterns were not as expected or were not evident. The strongest trends occurred at 2 Utah sites that had ≥14 y of data. At these sites, cold-water taxa were negatively correlated with air temperature, and, when years were grouped into hottest- and coldest-year samples, were strongly reduced in the hottest-year samples. Results suggest that thermal-preference metrics show promise for application in a biomonitoring context to differentiate climate-related responses from other stressors.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"122 1","pages":"1410 - 1423"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74859158","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}
M. Feio, C. Coimbra, M. Graça, S. Nichols, R. Norris
Abstract We analyzed long-term changes in macroinvertebrate communities in a Mediterranean temporary stream in southern Portugal over 15 y (1993–2008) at 10 locations with 3 degrees of physicochemical disturbance (reference, high disturbance, and mild disturbance). We related year-to-year variation of macroinvertebrate communities to long-term (59 y) information on precipitation and temperature. Our goals were to: 1) determine the stability of macroinvertebrate communities in the stream, 2) establish the influence of physicochemical disturbance on community stability, 3) assess the influence of climate change on the macroinvertebrate communities, and 4) assess the interactive effects of climate change and disturbance level on macroinvertebrate communities. Community structure varied naturally from year to year, but changes in taxon richness and evenness were much stronger and more unpredictable in disturbed than in other sites. In the long term, the more diverse (reference) and the poorest (disturbed) communities were stable, whereas communities affected by mild disturbance slowly decreased in taxon richness (slope = −0.07, r2 = 0.38). This decrease could be a response to the continuous stress or to climate change. The multivariate patterns over time of invertebrate communities at mildly disturbed sites were the only patterns significantly correlated with climatic patterns. In the past 59 y in this Mediterranean area (southeastern Europe), winter temperature has increased 1°C and precipitation has decreased 1.5 mm/d. Marked changes in community composition (70–80% Bray–Curtis dissimilarity) occurred only in years of extremely low precipitation or temperature. In years of climatic extremes and at chemically disturbed sites, Orthocladiinae and Simuliidae became dominant. In this stream, a shift in community equity occurs before species elimination. This shift might be useful as an early warning for biodiversity loss because of disturbance or climate change. We recommend continued sampling of reference sites for monitoring purposes so that effects of climate change can be established and so that contemporary human disturbance can be assessed relative to an adjusted reference condition.
{"title":"The influence of extreme climatic events and human disturbance on macroinvertebrate community patterns of a Mediterranean stream over 15 y","authors":"M. Feio, C. Coimbra, M. Graça, S. Nichols, R. Norris","doi":"10.1899/09-158.1","DOIUrl":"https://doi.org/10.1899/09-158.1","url":null,"abstract":"Abstract We analyzed long-term changes in macroinvertebrate communities in a Mediterranean temporary stream in southern Portugal over 15 y (1993–2008) at 10 locations with 3 degrees of physicochemical disturbance (reference, high disturbance, and mild disturbance). We related year-to-year variation of macroinvertebrate communities to long-term (59 y) information on precipitation and temperature. Our goals were to: 1) determine the stability of macroinvertebrate communities in the stream, 2) establish the influence of physicochemical disturbance on community stability, 3) assess the influence of climate change on the macroinvertebrate communities, and 4) assess the interactive effects of climate change and disturbance level on macroinvertebrate communities. Community structure varied naturally from year to year, but changes in taxon richness and evenness were much stronger and more unpredictable in disturbed than in other sites. In the long term, the more diverse (reference) and the poorest (disturbed) communities were stable, whereas communities affected by mild disturbance slowly decreased in taxon richness (slope = −0.07, r2 = 0.38). This decrease could be a response to the continuous stress or to climate change. The multivariate patterns over time of invertebrate communities at mildly disturbed sites were the only patterns significantly correlated with climatic patterns. In the past 59 y in this Mediterranean area (southeastern Europe), winter temperature has increased 1°C and precipitation has decreased 1.5 mm/d. Marked changes in community composition (70–80% Bray–Curtis dissimilarity) occurred only in years of extremely low precipitation or temperature. In years of climatic extremes and at chemically disturbed sites, Orthocladiinae and Simuliidae became dominant. In this stream, a shift in community equity occurs before species elimination. This shift might be useful as an early warning for biodiversity loss because of disturbance or climate change. We recommend continued sampling of reference sites for monitoring purposes so that effects of climate change can be established and so that contemporary human disturbance can be assessed relative to an adjusted reference condition.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"24 1","pages":"1397 - 1409"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72703411","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 Climate change is expected to alter freshwater communities and accelerate extinction, but the exact processes are poorly known. Here, we appraise interannual variation between 2 sympatric planarians (Crenobia alpina and Phagocata vitta) in upland Welsh streams over 25 y during which 1 of this pair (C. alpina) disappeared. We tested 3 nonexclusive hypotheses involving: 1) long-term changes in stream chemistry, 2) interspecific competition, and 3) climatic variation or directional change to explain this apparent local extinction. Several lines of evidence revealed potential exploitation competition between C. alpina and P. vitta. Coexistence was confined to conditions with high prey abundance (recorded as the abundance of Ephemeroptera, Plecoptera, and Trichoptera) and summer temperatures <12.5°C, whereas P. vitta dominated at sites with higher temperature, greater discharge, and lower prey abundance. The loss of C. alpina in the Llyn Brianne experimental catchments coincided with the largest-ever positive amplification of the North Atlantic Oscillation (NAO) in 1989 to 1994, accompanied by increased stream temperature, increased winter discharge, 2 summer droughts, and markedly reduced prey abundance. We suggest that interspecific competition and this prolonged climatic event acted in concert to favor P. vitta over C. alpina. Since its local loss, summer stream temperatures have generally exceeded the favorable range for C. alpina and, coupled with weak dispersal ability, probably explain its continued absence. Our data are consistent with the prediction that extreme climatic events will affect small, fluctuating populations. Nevertheless, this case study demonstrates clear difficulties in identifying unequivocally the exact climatic processes causing extinction where: 1) evidence is confined to weak inference, 2) responses to complex climatic events are nonlinear, 3) interactions occur among species or between climate and ecological processes, and 4) assessments are made retrospectively following extinctions.
{"title":"Evidence for the role of climate in the local extinction of a cool-water triclad","authors":"I. Durance, S. Ormerod","doi":"10.1899/09-159.1","DOIUrl":"https://doi.org/10.1899/09-159.1","url":null,"abstract":"Abstract Climate change is expected to alter freshwater communities and accelerate extinction, but the exact processes are poorly known. Here, we appraise interannual variation between 2 sympatric planarians (Crenobia alpina and Phagocata vitta) in upland Welsh streams over 25 y during which 1 of this pair (C. alpina) disappeared. We tested 3 nonexclusive hypotheses involving: 1) long-term changes in stream chemistry, 2) interspecific competition, and 3) climatic variation or directional change to explain this apparent local extinction. Several lines of evidence revealed potential exploitation competition between C. alpina and P. vitta. Coexistence was confined to conditions with high prey abundance (recorded as the abundance of Ephemeroptera, Plecoptera, and Trichoptera) and summer temperatures <12.5°C, whereas P. vitta dominated at sites with higher temperature, greater discharge, and lower prey abundance. The loss of C. alpina in the Llyn Brianne experimental catchments coincided with the largest-ever positive amplification of the North Atlantic Oscillation (NAO) in 1989 to 1994, accompanied by increased stream temperature, increased winter discharge, 2 summer droughts, and markedly reduced prey abundance. We suggest that interspecific competition and this prolonged climatic event acted in concert to favor P. vitta over C. alpina. Since its local loss, summer stream temperatures have generally exceeded the favorable range for C. alpina and, coupled with weak dispersal ability, probably explain its continued absence. Our data are consistent with the prediction that extreme climatic events will affect small, fluctuating populations. Nevertheless, this case study demonstrates clear difficulties in identifying unequivocally the exact climatic processes causing extinction where: 1) evidence is confined to weak inference, 2) responses to complex climatic events are nonlinear, 3) interactions occur among species or between climate and ecological processes, and 4) assessments are made retrospectively following extinctions.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"130 1","pages":"1367 - 1378"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89704031","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 Climate change is gradual and long-term, consistently collected data are required to detect resulting biological responses and to separate such responses from local effects of human activities that monitoring programs usually are designed to assess. The reference-condition approach is commonly used in freshwater assessments that use predictive modeling, but a consistent reference condition is required to maintain the relevance and integrity of results over the long term. We investigated whether external influences, such as climate change, inhibited clear interpretation of bioassessment results in a study design using reference vs test sites. Macroinvertebrates were collected from 16 sites (11 sites affected by ski resorts and 5 reference sites) on 5 streams in 4 seasons each year from 1994 to 2008 within Kosciuszko National Park, Australia. We analyzed trends over 15 y to address questions regarding climate-change and macroinvertebrate bioindicators of stream condition (observed/expected [O/E] taxa; Stream Invertebrate Grade Number Average Level [SIGNAL] 2 scores; Simpson's Diversity; Ephemeroptera, Plecoptera, Trichoptera [EPT] richness ratio; and Oligochaeta abundance). Climate became slightly warmer and less humid (p < 0.0001), but no significant relationships between climate variables and bioindicators were evident. All bioindicators consistently distinguished between test and reference sites in all seasons. All bioindicators except for O/E taxa scores differed among streams (regardless of site type). O/E taxa are inherently adjusted for specific stream characteristics, and, thus, were robust to differences in stream type while remaining sensitive to reference and test site variation. Generally, reference and test sites did not respond differently to any gradual climate changes. Furthermore, the reference sites sampled through time remained in a condition equivalent to the previously defined reference condition and provided a valid comparison for current test sites of unknown condition. The bioindicators used here were insensitive to the small but significant changes in climate detected over the 15-y study. However, extreme climate-related events (such as severe drought and extensive bushfire) were detected by the chosen bioindicators at both reference and test sites. Ecological outcomes of climate change can be accounted for only by an appropriate study design that includes standardized sampling of fixed sites (both test and reference) over long periods.
{"title":"Using the reference condition maintains the integrity of a bioassessment program in a changing climate","authors":"S. Nichols, W. Robinson, R. Norris","doi":"10.1899/09-165.1","DOIUrl":"https://doi.org/10.1899/09-165.1","url":null,"abstract":"Abstract Climate change is gradual and long-term, consistently collected data are required to detect resulting biological responses and to separate such responses from local effects of human activities that monitoring programs usually are designed to assess. The reference-condition approach is commonly used in freshwater assessments that use predictive modeling, but a consistent reference condition is required to maintain the relevance and integrity of results over the long term. We investigated whether external influences, such as climate change, inhibited clear interpretation of bioassessment results in a study design using reference vs test sites. Macroinvertebrates were collected from 16 sites (11 sites affected by ski resorts and 5 reference sites) on 5 streams in 4 seasons each year from 1994 to 2008 within Kosciuszko National Park, Australia. We analyzed trends over 15 y to address questions regarding climate-change and macroinvertebrate bioindicators of stream condition (observed/expected [O/E] taxa; Stream Invertebrate Grade Number Average Level [SIGNAL] 2 scores; Simpson's Diversity; Ephemeroptera, Plecoptera, Trichoptera [EPT] richness ratio; and Oligochaeta abundance). Climate became slightly warmer and less humid (p < 0.0001), but no significant relationships between climate variables and bioindicators were evident. All bioindicators consistently distinguished between test and reference sites in all seasons. All bioindicators except for O/E taxa scores differed among streams (regardless of site type). O/E taxa are inherently adjusted for specific stream characteristics, and, thus, were robust to differences in stream type while remaining sensitive to reference and test site variation. Generally, reference and test sites did not respond differently to any gradual climate changes. Furthermore, the reference sites sampled through time remained in a condition equivalent to the previously defined reference condition and provided a valid comparison for current test sites of unknown condition. The bioindicators used here were insensitive to the small but significant changes in climate detected over the 15-y study. However, extreme climate-related events (such as severe drought and extensive bushfire) were detected by the chosen bioindicators at both reference and test sites. Ecological outcomes of climate change can be accounted for only by an appropriate study design that includes standardized sampling of fixed sites (both test and reference) over long periods.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"29 1","pages":"1459 - 1471"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89882844","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 Despite the uncertainties in the rate of climate change, the Atlantic zone of northwestern Europe is expected to experience warmer, wetter winters and wetter summers than at present. Summer precipitation probably will depend on short, heavy rain showers between dry periods. Changes in the amount, frequency, and intensity of precipitation are expected to change stream discharge patterns, especially in rainwater-fed lowland streams, which will shift toward more dynamic flow regimes. Indices of discharge dynamics were used to assess the effect of changes in climate through changes in hydrology and land and water use on natural lowland stream macroinvertebrate communities. Discharge dynamics were significantly correlated with macroinvertebrate community structure, current velocity, and organic material preference. Our results demonstrate important influences of dynamic discharge regimes and extreme flows on macroinvertebrate community structure. Predictions of the ecological effects of climate change and of changes in land and water use indicate impaired ecological conditions in lowland streams of the Atlantic zone of northwestern Europe. Scenario tests involving different climate and landuse options suggest that current restoration practices and planned restoration activities can positively interact to reduce negative effects of climate change on lowland stream ecosystems.
{"title":"Using discharge dynamics characteristics to predict the effects of climate change on macroinvertebrates in lowland streams","authors":"P. Verdonschot, M. W. van den Hoorn","doi":"10.1899/09-154.1","DOIUrl":"https://doi.org/10.1899/09-154.1","url":null,"abstract":"Abstract Despite the uncertainties in the rate of climate change, the Atlantic zone of northwestern Europe is expected to experience warmer, wetter winters and wetter summers than at present. Summer precipitation probably will depend on short, heavy rain showers between dry periods. Changes in the amount, frequency, and intensity of precipitation are expected to change stream discharge patterns, especially in rainwater-fed lowland streams, which will shift toward more dynamic flow regimes. Indices of discharge dynamics were used to assess the effect of changes in climate through changes in hydrology and land and water use on natural lowland stream macroinvertebrate communities. Discharge dynamics were significantly correlated with macroinvertebrate community structure, current velocity, and organic material preference. Our results demonstrate important influences of dynamic discharge regimes and extreme flows on macroinvertebrate community structure. Predictions of the ecological effects of climate change and of changes in land and water use indicate impaired ecological conditions in lowland streams of the Atlantic zone of northwestern Europe. Scenario tests involving different climate and landuse options suggest that current restoration practices and planned restoration activities can positively interact to reduce negative effects of climate change on lowland stream ecosystems.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"37 1","pages":"1491 - 1509"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86144394","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 Aquatic ecosystems and their fauna are vulnerable to a variety of climate-related changes. Benthic macroinvertebrates are used frequently by water-quality agencies to monitor the status of aquatic resources. We used several regionally distributed state bioassessment data sets to analyze how climate change might influence metrics used to define ecological condition of streams. Many widely used, taxonomically based metrics were composed of both cold- and warm-water-preference taxa, and differing responses of these temperature-preference groups to climate-induced changes in stream temperatures could undermine assessment of stream condition. Climate responsiveness of these trait groups varied among states and ecoregions, but the groups generally were sensitive to changing temperature conditions. Temperature sensitivity of taxa and their sensitivity to organic pollution were moderately but significantly correlated. Therefore, metrics selected for condition assessments because taxa are sensitive to disturbance or to conventional pollutants also were sensitive to changes in temperature. We explored the feasibility of modifying metrics by partitioning components based on temperature sensitivity to reduce the likelihood that responses to climate change would confound responses to impairment from other causes and to facilitate tracking of climate-change-related taxon losses and replacements.
{"title":"Vulnerability of biological metrics and multimetric indices to effects of climate change","authors":"Anna T. Hamilton, Jen Stamp, B. Bierwagen","doi":"10.1899/10-053.1","DOIUrl":"https://doi.org/10.1899/10-053.1","url":null,"abstract":"Abstract Aquatic ecosystems and their fauna are vulnerable to a variety of climate-related changes. Benthic macroinvertebrates are used frequently by water-quality agencies to monitor the status of aquatic resources. We used several regionally distributed state bioassessment data sets to analyze how climate change might influence metrics used to define ecological condition of streams. Many widely used, taxonomically based metrics were composed of both cold- and warm-water-preference taxa, and differing responses of these temperature-preference groups to climate-induced changes in stream temperatures could undermine assessment of stream condition. Climate responsiveness of these trait groups varied among states and ecoregions, but the groups generally were sensitive to changing temperature conditions. Temperature sensitivity of taxa and their sensitivity to organic pollution were moderately but significantly correlated. Therefore, metrics selected for condition assessments because taxa are sensitive to disturbance or to conventional pollutants also were sensitive to changes in temperature. We explored the feasibility of modifying metrics by partitioning components based on temperature sensitivity to reduce the likelihood that responses to climate change would confound responses to impairment from other causes and to facilitate tracking of climate-change-related taxon losses and replacements.","PeriodicalId":49987,"journal":{"name":"Journal of the North American Benthological Society","volume":"63 1","pages":"1379 - 1396"},"PeriodicalIF":0.0,"publicationDate":"2010-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84874269","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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