Pub Date : 2006-03-01DOI: 10.1127/0003-9136/2006/0165-0313
S. Malkin, O. Johannsson, W. Taylor
This investigation reports the community composition and biomass size-distribution of crustacean zooplankton communities in five small fishless lakes of the Precambrian Shield in Algonquin Provincial Park across one or two growing seasons. Contrary to predictions based on the size efficiency hypothesis and invertebrate predation models, zooplankton in these lakes were predominantly small. In most of the lakes surveyed, zooplankton communities were dominated by small calanoid copepods (mean adult body length 1.5 mm) make up more than 25 % of the zooplankton biomass. Chaoborus abundance among these fishless lakes was an order of magnitude greater than in other lakes in the region with fish. We suggest the relatively small biomass of large bodied zooplankton compared with other fishless lakes is due to heavy Chaoborus predation combined with slowed zooplankton productivity in low pH waters. Despite the absence of large Cladocera, the relationship between zooplankton and phytoplankton biomass indicates strong "top-down" effects on phytoplankton. Grazing experiments in one of the lakes, and in a nearby lake with fish, indicate high grazing on some phytoplankton species, especially small dinoflagellates, and on protozoa.
{"title":"Small-bodied zooplankton communities yet strong top-down effects on phytoplankton in the absence of fish","authors":"S. Malkin, O. Johannsson, W. Taylor","doi":"10.1127/0003-9136/2006/0165-0313","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0313","url":null,"abstract":"This investigation reports the community composition and biomass size-distribution of crustacean zooplankton communities in five small fishless lakes of the Precambrian Shield in Algonquin Provincial Park across one or two growing seasons. Contrary to predictions based on the size efficiency hypothesis and invertebrate predation models, zooplankton in these lakes were predominantly small. In most of the lakes surveyed, zooplankton communities were dominated by small calanoid copepods (mean adult body length 1.5 mm) make up more than 25 % of the zooplankton biomass. Chaoborus abundance among these fishless lakes was an order of magnitude greater than in other lakes in the region with fish. We suggest the relatively small biomass of large bodied zooplankton compared with other fishless lakes is due to heavy Chaoborus predation combined with slowed zooplankton productivity in low pH waters. Despite the absence of large Cladocera, the relationship between zooplankton and phytoplankton biomass indicates strong \"top-down\" effects on phytoplankton. Grazing experiments in one of the lakes, and in a nearby lake with fish, indicate high grazing on some phytoplankton species, especially small dinoflagellates, and on protozoa.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79269318","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}
Pub Date : 2006-02-01DOI: 10.1127/0003-9136/2006/0165-0209
A. Zhulidov, T. Nalepa, A. V. Kozhara, D. A. Zhulidov, T. Gurtovaya
We sampled sites in the lower Don River system, Russia between 1977 and 2004 (5 sites) or between 1999 and 2004 (10 sites) to determine relative trends in two dreissenid species, Dreissena bugensis and Dreissena polymorpha. The sites were located in the main river, in connecting reservoirs, and in a major tributary, the Man- ych River. For sites sampled beginning in 1977, D. bugensis was first found in the lower river in 1980 and then more upstream in 1991. The relative proportion of D. bugensis increased to reach a maximum of 30-50% of the dreissenid population by 1999. After 1999, this species decreased at 14 of the 15 sites. At sites in the Don River, the proportion that D. bugensis comprised of the total dreissenid population after 1999 declined from 25-50% to 10-18%, whereas at sites in the Manych River the propor- tion declined from 65-75 % to 33-43 %. The decline of D. bugensis relative to D. polymorpha is unique; in most other water bodies D. bugensis displaces D. poly- morpha over time because of its superior physiological attributes. Reasons for the rela- tive decline of D. bugensis are unclear, but we speculate that selective predation by fish may be a potential factor.
{"title":"Recent trends in relative abundance of two dreissenid species, Dreissena polymorpha and Dreissena bugensis in the Lower Don River system, Russia","authors":"A. Zhulidov, T. Nalepa, A. V. Kozhara, D. A. Zhulidov, T. Gurtovaya","doi":"10.1127/0003-9136/2006/0165-0209","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0209","url":null,"abstract":"We sampled sites in the lower Don River system, Russia between 1977 and 2004 (5 sites) or between 1999 and 2004 (10 sites) to determine relative trends in two dreissenid species, Dreissena bugensis and Dreissena polymorpha. The sites were located in the main river, in connecting reservoirs, and in a major tributary, the Man- ych River. For sites sampled beginning in 1977, D. bugensis was first found in the lower river in 1980 and then more upstream in 1991. The relative proportion of D. bugensis increased to reach a maximum of 30-50% of the dreissenid population by 1999. After 1999, this species decreased at 14 of the 15 sites. At sites in the Don River, the proportion that D. bugensis comprised of the total dreissenid population after 1999 declined from 25-50% to 10-18%, whereas at sites in the Manych River the propor- tion declined from 65-75 % to 33-43 %. The decline of D. bugensis relative to D. polymorpha is unique; in most other water bodies D. bugensis displaces D. poly- morpha over time because of its superior physiological attributes. Reasons for the rela- tive decline of D. bugensis are unclear, but we speculate that selective predation by fish may be a potential factor.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89402105","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}
Pub Date : 2006-02-01DOI: 10.1127/0003-9136/2006/0165-0167
A. Michels, G. Umaña, U. Raeder
Epilithic diatom assemblages from neotropical streams draining into Golfo Dulce (Costa Rica) were studied to determine how diatoms were related to measured environmental conditions. Twenty-three sites, affected by different land use practices, were selected and monitored for 21 months. Water chemistry was characterized by moderate specific conductivity (100 - 300 µS/cm), neutral to alkaline pH and moderate to high values of soluble reactive phosphorus (10-70 µg/L). Anthropogenic impact was reflected in lower oxygen saturation, elevated nitrogen compounds and measured sedi- ment load. A diverse diatom flora of 212 taxa was found. Patterns in the diatom distri- bution in relation to environmental variables, as revealed by canonical correspondence analysis, showed that riparian shading, pH, conductivity, current velocity and turbidity were the most important measured factors in determining species composition. The re- lationship between conductivity and pH was sufficiently strong to develop weighted- averaging regression and calibration models. Optima and tolerances of the most com- mon diatom taxa are presented.
{"title":"Epilithic diatom assemblages in rivers draining into Golfo Dulce (Costa Rica) and their relationship to water chemistry, habitat characteristics and land use","authors":"A. Michels, G. Umaña, U. Raeder","doi":"10.1127/0003-9136/2006/0165-0167","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0167","url":null,"abstract":"Epilithic diatom assemblages from neotropical streams draining into Golfo Dulce (Costa Rica) were studied to determine how diatoms were related to measured environmental conditions. Twenty-three sites, affected by different land use practices, were selected and monitored for 21 months. Water chemistry was characterized by moderate specific conductivity (100 - 300 µS/cm), neutral to alkaline pH and moderate to high values of soluble reactive phosphorus (10-70 µg/L). Anthropogenic impact was reflected in lower oxygen saturation, elevated nitrogen compounds and measured sedi- ment load. A diverse diatom flora of 212 taxa was found. Patterns in the diatom distri- bution in relation to environmental variables, as revealed by canonical correspondence analysis, showed that riparian shading, pH, conductivity, current velocity and turbidity were the most important measured factors in determining species composition. The re- lationship between conductivity and pH was sufficiently strong to develop weighted- averaging regression and calibration models. Optima and tolerances of the most com- mon diatom taxa are presented.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86747159","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}
Pub Date : 2006-02-01DOI: 10.1127/0003-9136/2006/0165-0269
Xiao-wei Zhao, M. Fox, D. Lasenby
To examine the interactive effects of prey density, prey mobility and habitat structure on prey selection by benthic feeding fish, feeding experiments were conducted with 95-105 mm (total length) pumpkinseed (Lepomis gibbosus), given four sizes ( 9 mm) of active or immobilized amphipods (Gammarus pseudolimnaeus) as prey. The experiments involved the assessment of prey size selectivity, total number of prey consumed and size-specific indicators of foraging efficiency such as capture success and handling time. Pumpkinseeds were size selective only at medium and high prey densities, preferring large Gammarus when selectivity occurred. The proportion of mobile and immobile prey consumed increased with prey size in unstructured habitat, whereas no selectivity occurred with mobile prey in structured habitat. Both habitat and prey density significantly affected prey consumption, with more prey eaten at higher densities and in unstructured habitat. Prey mobility did not affect the number of prey consumed when mobile or immobile prey were offered in separate trials, but the consumption rate of immobile prey increased in structured habitat when they were offered with mobile prey in the same trial. We conclude that prey density and habitat structure affect pumpkinseed size selectivity and consumption rates in a similar manner, whereas the effect of prey mobility on these factors is more dependent on the combination of density and habitat and on whether mobile and immobile prey are present at the same time.
{"title":"Effect of prey density, prey mobility and habitat structure on size selection and consumption of amphipods by a benthic feeding fish","authors":"Xiao-wei Zhao, M. Fox, D. Lasenby","doi":"10.1127/0003-9136/2006/0165-0269","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0269","url":null,"abstract":"To examine the interactive effects of prey density, prey mobility and habitat structure on prey selection by benthic feeding fish, feeding experiments were conducted with 95-105 mm (total length) pumpkinseed (Lepomis gibbosus), given four sizes ( 9 mm) of active or immobilized amphipods (Gammarus pseudolimnaeus) as prey. The experiments involved the assessment of prey size selectivity, total number of prey consumed and size-specific indicators of foraging efficiency such as capture success and handling time. Pumpkinseeds were size selective only at medium and high prey densities, preferring large Gammarus when selectivity occurred. The proportion of mobile and immobile prey consumed increased with prey size in unstructured habitat, whereas no selectivity occurred with mobile prey in structured habitat. Both habitat and prey density significantly affected prey consumption, with more prey eaten at higher densities and in unstructured habitat. Prey mobility did not affect the number of prey consumed when mobile or immobile prey were offered in separate trials, but the consumption rate of immobile prey increased in structured habitat when they were offered with mobile prey in the same trial. We conclude that prey density and habitat structure affect pumpkinseed size selectivity and consumption rates in a similar manner, whereas the effect of prey mobility on these factors is more dependent on the combination of density and habitat and on whether mobile and immobile prey are present at the same time.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86297469","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}
Pub Date : 2006-02-01DOI: 10.1127/0003-9136/2006/0165-0145
P. Fink, L. Peters, E. Elert
Abstract: Ecological stoichiometry is considered a key concept in understanding con-straints in energy transfer at the plant-herbivore interface. However, whether this con-cept is relevant for benthic freshwater ecosystems is not fully known. Therefore, afield survey was conducted in 2003 during the growing season in the littoral zone ofLake Constance, a large pre-alpine lake in central Europe. The aim was to assess tem-poral variation in the elemental stoichiometric composition in both herbivorous macro-invertebrates and their food resource, the periphyton in two different lakes. The peri-phyton showed large temporal and spatial variation in carbon, nitrogen, and phospho-rus content, with particularly high molar C:P ratios of up to 1225:1. Periphyton C:Pand C:N ratios were often high and constantly above the Redfield ratio that is consid-ered optimal for autotrophic growth. In contrast to the pronounced fluctuations in thenutrient ratios of their food resource, the herbivorous macroinvertebrates showed onlyvery little variation in their nutrient ratios, which indicated that they are homeostatic,i.e., physiologically restricted to a comparatively narrow range of C:P and C:N ratios.Distinct species-specific C : P and C : N ratios were found for different taxonomicgroups of macroinvertebrates, which indicated different requirements of optimal die-tary C:P and C:N ratios and which might influence the ability of the taxa to competefor limiting elemental nutrients. Considering the temporally very high C:P and C:Nratios of the periphytic resource and the very low ratios of the consumer body tissue,this stoichiometric mismatch is likely to constrain growth and reproduction of these lit-toral invertebrates. Therefore, the concept of stoichiometric food quality limitationmight also be applicable to the littoral food web in lakes.Key words: benthos, C:N:P ratio, ecological stoichiometry, herbivory, homeostasis,lake littoral, macroinvertebrates, mismatch, nutrient ratios, phosphorus.
{"title":"Stoichiometric mismatch between littoral invertebrates and their periphyton food","authors":"P. Fink, L. Peters, E. Elert","doi":"10.1127/0003-9136/2006/0165-0145","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0145","url":null,"abstract":"Abstract: Ecological stoichiometry is considered a key concept in understanding con-straints in energy transfer at the plant-herbivore interface. However, whether this con-cept is relevant for benthic freshwater ecosystems is not fully known. Therefore, afield survey was conducted in 2003 during the growing season in the littoral zone ofLake Constance, a large pre-alpine lake in central Europe. The aim was to assess tem-poral variation in the elemental stoichiometric composition in both herbivorous macro-invertebrates and their food resource, the periphyton in two different lakes. The peri-phyton showed large temporal and spatial variation in carbon, nitrogen, and phospho-rus content, with particularly high molar C:P ratios of up to 1225:1. Periphyton C:Pand C:N ratios were often high and constantly above the Redfield ratio that is consid-ered optimal for autotrophic growth. In contrast to the pronounced fluctuations in thenutrient ratios of their food resource, the herbivorous macroinvertebrates showed onlyvery little variation in their nutrient ratios, which indicated that they are homeostatic,i.e., physiologically restricted to a comparatively narrow range of C:P and C:N ratios.Distinct species-specific C : P and C : N ratios were found for different taxonomicgroups of macroinvertebrates, which indicated different requirements of optimal die-tary C:P and C:N ratios and which might influence the ability of the taxa to competefor limiting elemental nutrients. Considering the temporally very high C:P and C:Nratios of the periphytic resource and the very low ratios of the consumer body tissue,this stoichiometric mismatch is likely to constrain growth and reproduction of these lit-toral invertebrates. Therefore, the concept of stoichiometric food quality limitationmight also be applicable to the littoral food web in lakes.Key words: benthos, C:N:P ratio, ecological stoichiometry, herbivory, homeostasis,lake littoral, macroinvertebrates, mismatch, nutrient ratios, phosphorus.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80727299","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}
Pub Date : 2006-02-01DOI: 10.1127/0003-9136/2006/0165-0191
M. Czarnoleski, J. Kozłowski, Przemysław Kubajak, K. Lewandowski, Tomasz Müller, A. Stańczykowska, K. Surówka
We examined the growth pattern and shell strength of zebra mussels Dreissena polymorpha in eight European locations characterised by different survival rates, pH levels and calcium availability, testing whether trait variability can be attributed to anti-predator responses and how their expression might depend on mussel size and water chemistry. Differences in chemical conditions were unrelated to the cross-population gradient in survivorship, suggesting other agents such as predators as determinants of mussel survival. Increased population mortality was associated with production of stronger shells by mussels 8, 10 and 12 mm long, and with slower growth of 12- and 14-mm individuals. Shell strengthening was unrelated to growth rate across populations. Mortality correlated positively with Bertalanffy's growth coefficient and negatively with asymptotic size. Chemical parameters were unrelated to growth patterns, but they had interactive effects with mortality on the crush resistance of 8- and 10-mm mussels. Under low-mortality conditions, higher calcium concentrations and lower pH stimulated production of stronger shells; the positive link between shell strength and population mortality was detectable across lower to medium calcium levels and medium to higher pH values. The results suggest adaptive responses to predation through increasing crush resistance and diversion of resources from growth to reproduction. They indicate that water chemistry can mediate induction of anti-predator responses, and that their efficacy changes over the mussel lifetime. We argue that a full consideration of the post-invasive polymorphism of zebra mussels must incorporate the interplay between environmental conditions and adaptive responses to mortality risk.
{"title":"Cross-habitat differences in crush resistance and growth pattern of zebra mussels ( Dreissena polymorpha ): effects of calcium availability and predator pressure","authors":"M. Czarnoleski, J. Kozłowski, Przemysław Kubajak, K. Lewandowski, Tomasz Müller, A. Stańczykowska, K. Surówka","doi":"10.1127/0003-9136/2006/0165-0191","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0191","url":null,"abstract":"We examined the growth pattern and shell strength of zebra mussels Dreissena polymorpha in eight European locations characterised by different survival rates, pH levels and calcium availability, testing whether trait variability can be attributed to anti-predator responses and how their expression might depend on mussel size and water chemistry. Differences in chemical conditions were unrelated to the cross-population gradient in survivorship, suggesting other agents such as predators as determinants of mussel survival. Increased population mortality was associated with production of stronger shells by mussels 8, 10 and 12 mm long, and with slower growth of 12- and 14-mm individuals. Shell strengthening was unrelated to growth rate across populations. Mortality correlated positively with Bertalanffy's growth coefficient and negatively with asymptotic size. Chemical parameters were unrelated to growth patterns, but they had interactive effects with mortality on the crush resistance of 8- and 10-mm mussels. Under low-mortality conditions, higher calcium concentrations and lower pH stimulated production of stronger shells; the positive link between shell strength and population mortality was detectable across lower to medium calcium levels and medium to higher pH values. The results suggest adaptive responses to predation through increasing crush resistance and diversion of resources from growth to reproduction. They indicate that water chemistry can mediate induction of anti-predator responses, and that their efficacy changes over the mussel lifetime. We argue that a full consideration of the post-invasive polymorphism of zebra mussels must incorporate the interplay between environmental conditions and adaptive responses to mortality risk.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77140424","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}
Pub Date : 2006-02-01DOI: 10.1127/0003-9136/2006/0165-0241
D. Wooster, S. Debano
Woody riparian vegetation plays important roles in stream ecosystems and its presence can have strong impacts on stream fauna. Agricultural practices have led to the removal and fragmentation of woody riparian vegetation in many watersheds. It is unclear whether small, isolated patches of woody riparian vegetation continue to exert important influences on stream fauna. The impact of these types of patches and the influence of the size of the patches on stream macroinvertebrates was examined in a watershed in northeastern Oregon that is dominated by dryland wheat production. Half of the study reaches flowed through patches of woody riparian vegetation and half flowed through areas in which there was no woody vegetation and wheat fields were found within 3 m of the stream. Stream reaches flowing through patches of woody riparian vegetation had higher taxa richness than those flowing through areas lacking woody vegetation. Size of woody patches, as measured by patch length, was positively correlated with shredder abundance, scraper abundance and diversity, and was also correlated with overall community composition as defined by ordination scores. An analysis of individual taxa revealed that patch length was positively associated with nine taxa that are known to be sensitive to human disturbances and negatively associated with one taxon which is considered tolerant of human disturbances. Patch length was also negatively associated with the proportion of sediment on the substrate and it appears that this environmental factor might drive the relationships between patch length and the abundance of the ten taxa. Woody riparian patch width was also examined as a measure of size. In contrast to length, patch width was not correlated with any metric of macroinvertebrate community structure. The results of this study also revealed that macroinvertebrate community structure was influenced by the drainage the study sites were found in. This was unexpected because the study was conducted in a small watershed and the sites within each drainage were specifically chosen to be similar in land use and geology. These results indicate that patch length may be as important, if not more important, than patch width in influencing stream ecosystems. However, the "buffer" literature generally considers only buffer width when examining the relationship between patch size and stream systems. This study highlights the need to consider patch length, as well as width, in studies examining the effect of patches of riparian vegetation on stream fauna, in the design of buffer projects, and in the monitoring of existing project effectiveness.
{"title":"Effect of woody riparian patches in croplands on stream macroinvertebrates","authors":"D. Wooster, S. Debano","doi":"10.1127/0003-9136/2006/0165-0241","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0241","url":null,"abstract":"Woody riparian vegetation plays important roles in stream ecosystems and its presence can have strong impacts on stream fauna. Agricultural practices have led to the removal and fragmentation of woody riparian vegetation in many watersheds. It is unclear whether small, isolated patches of woody riparian vegetation continue to exert important influences on stream fauna. The impact of these types of patches and the influence of the size of the patches on stream macroinvertebrates was examined in a watershed in northeastern Oregon that is dominated by dryland wheat production. Half of the study reaches flowed through patches of woody riparian vegetation and half flowed through areas in which there was no woody vegetation and wheat fields were found within 3 m of the stream. Stream reaches flowing through patches of woody riparian vegetation had higher taxa richness than those flowing through areas lacking woody vegetation. Size of woody patches, as measured by patch length, was positively correlated with shredder abundance, scraper abundance and diversity, and was also correlated with overall community composition as defined by ordination scores. An analysis of individual taxa revealed that patch length was positively associated with nine taxa that are known to be sensitive to human disturbances and negatively associated with one taxon which is considered tolerant of human disturbances. Patch length was also negatively associated with the proportion of sediment on the substrate and it appears that this environmental factor might drive the relationships between patch length and the abundance of the ten taxa. Woody riparian patch width was also examined as a measure of size. In contrast to length, patch width was not correlated with any metric of macroinvertebrate community structure. The results of this study also revealed that macroinvertebrate community structure was influenced by the drainage the study sites were found in. This was unexpected because the study was conducted in a small watershed and the sites within each drainage were specifically chosen to be similar in land use and geology. These results indicate that patch length may be as important, if not more important, than patch width in influencing stream ecosystems. However, the \"buffer\" literature generally considers only buffer width when examining the relationship between patch size and stream systems. This study highlights the need to consider patch length, as well as width, in studies examining the effect of patches of riparian vegetation on stream fauna, in the design of buffer projects, and in the monitoring of existing project effectiveness.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90882731","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}
Pub Date : 2006-02-01DOI: 10.1127/0003-9136/2006/0165-0221
O. Olapade, M. Crissman, L. Leff
The ecological significance of microbial communities in aquatic systems has been documented to varying degrees in marine and lentic systems; however much less is known about their relative abundance and distribution among streams with different environmental conditions. In this study, the relative abundance and distribution of different bacterial taxa, virus-like-particles (VLP) and protozoa in planktonic communities from nine streams in different regions of the USA were examined. There were clear differences in the abundance and distribution of the microorganisms examined among sites within a stream and among the streams. Also, there were strong relationships between the abundance of some of the microbiological variables measured and the environmental conditions of the streams. Most of the bacterial taxa examined were correlated with chlorophyll-a concentrations, while no significant relationships were observed between VLP numbers and any of the environmental or microbiological variables measured in the streams. In contrast, protozoa numbers were correlated with nitrate and dissolved organic carbon (DOC) concentrations. Our results suggest that differences in environmental conditions influence microbial numbers and distribution among the streams examined.
{"title":"Comparison of Planktonic Microbial Communities among Nine North American Streams","authors":"O. Olapade, M. Crissman, L. Leff","doi":"10.1127/0003-9136/2006/0165-0221","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0221","url":null,"abstract":"The ecological significance of microbial communities in aquatic systems has been documented to varying degrees in marine and lentic systems; however much less is known about their relative abundance and distribution among streams with different environmental conditions. In this study, the relative abundance and distribution of different bacterial taxa, virus-like-particles (VLP) and protozoa in planktonic communities from nine streams in different regions of the USA were examined. There were clear differences in the abundance and distribution of the microorganisms examined among sites within a stream and among the streams. Also, there were strong relationships between the abundance of some of the microbiological variables measured and the environmental conditions of the streams. Most of the bacterial taxa examined were correlated with chlorophyll-a concentrations, while no significant relationships were observed between VLP numbers and any of the environmental or microbiological variables measured in the streams. In contrast, protozoa numbers were correlated with nitrate and dissolved organic carbon (DOC) concentrations. Our results suggest that differences in environmental conditions influence microbial numbers and distribution among the streams examined.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88501491","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}
Pub Date : 2006-01-01DOI: 10.1127/0003-9136/2006/0165-0037
A. Boggero, V. Lencioni
The invertebrate fauna of 21 high altitude lakes on the southern side of the Alps (Italy and Switzerland) were sampled once in the 1990 s. A total of 193 taxa was identified in 48 samples: 66 taxa were exclusive to the littoral zone, 17 to the outlets and 23 to the inlets. Chironomids prevailed in all environments with few exceptions. Inlets and littoral zones proved to be the richest habitats in number of taxa, while the littoral zones were richest in number of individuals. In all, 17,778 individuals were found in the Pennine-Lepontine Alps and 1966 in the Rhaetian ones. The number of taxa was 108 and 122, respectively. 69 taxa were exclusive to the former and 83 to the latter. Four groups of lakes have been distinguished by DCCA analysis applied to the littoral chironomid community. Water temperature, altitude, hydrochemistry, and lake area were the abiotic variables mostly related to chironomid distribution. Many steno-thermal species, typical of oligotrophic waters and high mountain streams were found, such as Zavrelimyia punctatissima, Diamesa latitarsis gr., Orthocladius frigidus, Prosimulium latimucro, Dictyogenus fontium, Baetis alpinus and Crenobia alpina. Only a few taxa such as D. fontium, Halesus radiatus, Plectrocnemia conspersa, Heterotris-socladius marcidus, Ablabesmyia sp., and Procladius sp. appeared to be tolerant to acidic conditions. These findings, as well as the rarity of molluscs, indicated that these environments are slightly acidic or at risk of acidification. Further studies on macroinvertebrates are required if they are to be used as possible indicators of local and global changes (e.g. acid deposition) in remote regions.
{"title":"Macroinvertebrates assemblages of high altitude lakes, inlets and outlets in the southern Alps","authors":"A. Boggero, V. Lencioni","doi":"10.1127/0003-9136/2006/0165-0037","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0037","url":null,"abstract":"The invertebrate fauna of 21 high altitude lakes on the southern side of the Alps (Italy and Switzerland) were sampled once in the 1990 s. A total of 193 taxa was identified in 48 samples: 66 taxa were exclusive to the littoral zone, 17 to the outlets and 23 to the inlets. Chironomids prevailed in all environments with few exceptions. Inlets and littoral zones proved to be the richest habitats in number of taxa, while the littoral zones were richest in number of individuals. In all, 17,778 individuals were found in the Pennine-Lepontine Alps and 1966 in the Rhaetian ones. The number of taxa was 108 and 122, respectively. 69 taxa were exclusive to the former and 83 to the latter. Four groups of lakes have been distinguished by DCCA analysis applied to the littoral chironomid community. Water temperature, altitude, hydrochemistry, and lake area were the abiotic variables mostly related to chironomid distribution. Many steno-thermal species, typical of oligotrophic waters and high mountain streams were found, such as Zavrelimyia punctatissima, Diamesa latitarsis gr., Orthocladius frigidus, Prosimulium latimucro, Dictyogenus fontium, Baetis alpinus and Crenobia alpina. Only a few taxa such as D. fontium, Halesus radiatus, Plectrocnemia conspersa, Heterotris-socladius marcidus, Ablabesmyia sp., and Procladius sp. appeared to be tolerant to acidic conditions. These findings, as well as the rarity of molluscs, indicated that these environments are slightly acidic or at risk of acidification. Further studies on macroinvertebrates are required if they are to be used as possible indicators of local and global changes (e.g. acid deposition) in remote regions.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84093206","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}
Pub Date : 2006-01-01DOI: 10.1127/0003-9136/2006/0165-0127
T. East, B. Sharfstein
Conducting long-term algal bioassays in large, complex systems such as Lake Okeechobee is an expensive and time-intensive undertaking, especially in comparison with physical and chemical monitoring. This paper describes a water quality-based decision tree model for predicting whether the phytoplankton in Lake Okeechobee is limited by light or nutrients. The model was developed and validated using the results of algal bioassays coupled with routinely monitored water quality data. Algal bioassays indicated that the factor most commonly limiting phytoplankton production in Lake Okeechobee for the period of October 1997 to November 2000 was light (59 %) followed by nitrogen (41 %). Limitation status of the phytoplankton was positively correlated with irradiance (in terms of Secchi depth/total depth) and phytoplankton biomass (in terms of chlorophyll-a) and negatively related to dissolved inorganic nitrogen and soluble reactive phosphorus concentrations. A cross-tabulation procedure was used to examine how the frequency of occurrence of light limitation and nutrient limitation varied as a function of these variables. The cross-tabulation procedure was also used to derive the empirical threshold values used to construct the model. This result supports both the accuracy of the derived critical threshold values and the validity of using chemical measurements in predicting whether light is limiting or nutrients are limiting in Lake Okeechobee. The model successfully predicted light limitation versus nutrient limitation in three independent validation data sets 70 % to 85 % of the time. When nutrient limiting conditions prevailed, the model did not successfully predict which nutrient (nitrogen, phosphorus, or a combination of nitrogen and phosphorus) was limiting. Our results suggest that the predictive abilities of the model could be enhanced by using time-specific data rather than averaged monthly data.
{"title":"Development of a decision tree model for the prediction of the limitation potential of phytoplankton in Lake Okeechobee, Florida, USA","authors":"T. East, B. Sharfstein","doi":"10.1127/0003-9136/2006/0165-0127","DOIUrl":"https://doi.org/10.1127/0003-9136/2006/0165-0127","url":null,"abstract":"Conducting long-term algal bioassays in large, complex systems such as Lake Okeechobee is an expensive and time-intensive undertaking, especially in comparison with physical and chemical monitoring. This paper describes a water quality-based decision tree model for predicting whether the phytoplankton in Lake Okeechobee is limited by light or nutrients. The model was developed and validated using the results of algal bioassays coupled with routinely monitored water quality data. Algal bioassays indicated that the factor most commonly limiting phytoplankton production in Lake Okeechobee for the period of October 1997 to November 2000 was light (59 %) followed by nitrogen (41 %). Limitation status of the phytoplankton was positively correlated with irradiance (in terms of Secchi depth/total depth) and phytoplankton biomass (in terms of chlorophyll-a) and negatively related to dissolved inorganic nitrogen and soluble reactive phosphorus concentrations. A cross-tabulation procedure was used to examine how the frequency of occurrence of light limitation and nutrient limitation varied as a function of these variables. The cross-tabulation procedure was also used to derive the empirical threshold values used to construct the model. This result supports both the accuracy of the derived critical threshold values and the validity of using chemical measurements in predicting whether light is limiting or nutrients are limiting in Lake Okeechobee. The model successfully predicted light limitation versus nutrient limitation in three independent validation data sets 70 % to 85 % of the time. When nutrient limiting conditions prevailed, the model did not successfully predict which nutrient (nitrogen, phosphorus, or a combination of nitrogen and phosphorus) was limiting. Our results suggest that the predictive abilities of the model could be enhanced by using time-specific data rather than averaged monthly data.","PeriodicalId":8118,"journal":{"name":"Archiv Fur Hydrobiologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2006-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89647657","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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