Abstract Setting conservation priorities is an important step when resources are finite. In devel... more Abstract Setting conservation priorities is an important step when resources are finite. In developing countries such as Iraq, information about aquatic habitats is quite limited and prioritizing such habitats for conservation requires a multidisciplinary approach to utilize available types of data efficiently. We divided aquatic ecosystems of the Kurdistan Region of northern Iraq into 76 planning units. Next, we compiled mayfly, stonefly, and caddisfly (Insecta: Ephemeroptera-Plecoptera-Trichoptera (EPT)) data for 33 of them; these units were ranked for EPT conservation using a combination of conservation indices. We selected the subset of units with the highest priority for EPT conservation and considered them to represent samples of healthy aquatic habitats in the region; we used these units, along with various landscape predictor variables, in correlative distribution modeling for healthy aquatic habitats across the entire region. Our approach resulted in identifying one lake and 23 riverine units as healthy aquatic habitats of conservation priority in the region. Our research shows that in developing countries where knowledge about aquatic habitats and species is minimal, conservation studies can still be conducted using water quality bioindicators along with a combination of conservation indices and spatial modeling.
Comparative Biochemistry and Physiology Part A: Physiology, 1989
ABSTRACT 1.1. Thais haemastoma were transferred from 30 to 15‰ and 15 to 30‰ S and ammonia excret... more ABSTRACT 1.1. Thais haemastoma were transferred from 30 to 15‰ and 15 to 30‰ S and ammonia excretion was measured for 72 hr.2.2. Increased ammonia excretion following transfer from high to low salinity was significantly greater in snails with the rare Lap allele, Lap94.3.3. Increased rates of nitrogen loss induced by salinity reductions could be responsible for maintaining the Lap94 allele at low frequency in estuarine populations of T. haemastoma.
Aquatic Conservation: Marine and Freshwater Ecosystems
1. Desert springs are highly threatened ecosystems inhabited by a substantial number of endemic s... more 1. Desert springs are highly threatened ecosystems inhabited by a substantial number of endemic species. 2. Macroinvertebrate communities of five springs in the northern Chihuahuan Desert of west Texas and south‐eastern New Mexico were sampled seasonally. Rather than focusing on individual taxa, this study examined the community structure of springs to identify patterns that are likely to reflect both local conditions and potential dispersal barriers. 3. In total, 46 774 individuals representing 109 taxa were collected with high relative abundances of gastropods, amphipods, and oligochaetes. Spatial variation in community composition was greater than temporal variation. 4. Although there were differences in the salinity content and concentrations of several major anions and cations among sites, these were not significant predictors of difference in community structure. Two springs sharing the same groundwater source contained similar macroin-vertebrate communities and had similar physicochemical conditions. Results from this study suggest that springs in the northern Chihuahuan Desert contain unique communities and endemic species owing to historical processes such as isolation and dispersal limitation, rather than contemporary processes such as environmental filtering and species sorting. 5. Springs located in the northern Chihuahuan Desert, like those located in other arid regions of the world, are valuable for their biodiversity because of their distinct invertebrate communities and high rates of endemism. Thus, they should be conserved individually to ensure the preservation of unique species and communities.
In the face of global climate change, organisms may respond to temperature increases by shifting ... more In the face of global climate change, organisms may respond to temperature increases by shifting their ranges poleward or to higher altitudes. However, the direction of range shifts in riverine systems is less clear. Because rivers are dendritic networks, there is only one dispersal route from any given location to another. Thus, range shifts are only possible if branches are connected by suitable habitat, and stream-dwelling organisms can disperse through these branches. We used Cumberlandia monodonta (Bivalvia: Unionoida: Margaritiferidae) as a model species to investigate the effects of climate change on population connectivity because a majority of contemporary populations are panmictic. We combined ecological niche models (ENMs) with population genetic simulations to investigate the effects of climate change on population connectivity and genetic diversity of C. monodonta. The ENMs were constructed using bioclimatic and landscape data to project shifts in suitable habitat under...
ABSTRACT Climate change and human population growth threaten the supply of fresh water for human ... more ABSTRACT Climate change and human population growth threaten the supply of fresh water for human use and freshwater biodiversity. Long-term studies are necessary to identify the effects of such temporal trends on biological and ecological phenomena; however, the collection of long-term data can be costly and time-consuming. We investigated the effect of hydrological variation over time on population dynamics in a perennial river of the northern Chihuahuan Desert, using an imperilled freshwater mussel (Popenaias popeii) as a model. We conducted a 15-year mark-and-recapture study, and distance sampling, to estimate demographic parameters while accounting for habitat heterogeneity and changes in river discharge. Recapture probability varied between microhabitats, and survival was positively correlated with river discharge. Survival and the finite rate of population growth were relatively stable over time. Over 60% of individuals were found at relatively high density in riffle habitats, which compose c. 16% of the total study area. Mean monthly temperature in the region increased over the past 100 years, and mean monthly discharge of the Black River declined over the past 65 years. With no significant trends in total monthly precipitation, declines in discharge suggest that reduction of stream flow is likely due to lowering of the water table and decreased groundwater recharge. Significant changes in climate and hydrological regimes, and increases in anthropogenic threats (increased water demand, degraded water quality) in the region, may induce significant declines in population size of this imperilled mussel. We demonstrated the importance of considering habitat heterogeneity and hydrological cycles over time to examine population dynamics. Survival of benthic invertebrates in desert streams is sensitive to hydrological cycles, which are expected to be altered via climate change and extensive water use. Species recovery plans need to incorporate knowledge of spatial distributions when designing strategies for habitat assessment and making conservation decisions.
Historical-to-recent climate change and anthropogenic disturbance affect species distributions an... more Historical-to-recent climate change and anthropogenic disturbance affect species distributions and genetic structure. The Rio Grande watershed of the United States and Mexico encompasses ecosystems that are intensively exploited, resulting in substantial degradation of aquatic habitats. While significant anthropogenic disturbances in the Rio Grande are recent, inhospitable conditions for freshwater organisms likely existed prior to such disturbances. A combination of anthropogenic and past climate factors may contribute to current distributions of aquatic fauna in the Rio Grande basin. We used mitochondrial DNA and 18 microsatellite loci to infer evolutionary history and genetic structure of an endangered freshwater mussel, Popenaias popeii, throughout the Rio Grande drainage. We estimated spatial connectivity and gene flow across extant populations of P. popeii and used ecological niche models (ENMs) and approximate Bayesian computation (ABC) to infer its evolutionary history durin...
The predaceous cladoceran, Bythotrephes cederstroemi (Schoedler 1877), was first noted in the Gre... more The predaceous cladoceran, Bythotrephes cederstroemi (Schoedler 1877), was first noted in the Great Lakes in late 1984, and had spread to Lakes Huron, Erie, Ontario, and Michigan by late summer of 1986. Zooplankton samples collected from Batchawana Bay, Lake Superior on 15 September 1988 contained large numbers of B. cederstroemi (122.8 individuals/m 2 ). Geographic variation in Great Lakes B.
Abstract Setting conservation priorities is an important step when resources are finite. In devel... more Abstract Setting conservation priorities is an important step when resources are finite. In developing countries such as Iraq, information about aquatic habitats is quite limited and prioritizing such habitats for conservation requires a multidisciplinary approach to utilize available types of data efficiently. We divided aquatic ecosystems of the Kurdistan Region of northern Iraq into 76 planning units. Next, we compiled mayfly, stonefly, and caddisfly (Insecta: Ephemeroptera-Plecoptera-Trichoptera (EPT)) data for 33 of them; these units were ranked for EPT conservation using a combination of conservation indices. We selected the subset of units with the highest priority for EPT conservation and considered them to represent samples of healthy aquatic habitats in the region; we used these units, along with various landscape predictor variables, in correlative distribution modeling for healthy aquatic habitats across the entire region. Our approach resulted in identifying one lake and 23 riverine units as healthy aquatic habitats of conservation priority in the region. Our research shows that in developing countries where knowledge about aquatic habitats and species is minimal, conservation studies can still be conducted using water quality bioindicators along with a combination of conservation indices and spatial modeling.
Comparative Biochemistry and Physiology Part A: Physiology, 1989
ABSTRACT 1.1. Thais haemastoma were transferred from 30 to 15‰ and 15 to 30‰ S and ammonia excret... more ABSTRACT 1.1. Thais haemastoma were transferred from 30 to 15‰ and 15 to 30‰ S and ammonia excretion was measured for 72 hr.2.2. Increased ammonia excretion following transfer from high to low salinity was significantly greater in snails with the rare Lap allele, Lap94.3.3. Increased rates of nitrogen loss induced by salinity reductions could be responsible for maintaining the Lap94 allele at low frequency in estuarine populations of T. haemastoma.
Aquatic Conservation: Marine and Freshwater Ecosystems
1. Desert springs are highly threatened ecosystems inhabited by a substantial number of endemic s... more 1. Desert springs are highly threatened ecosystems inhabited by a substantial number of endemic species. 2. Macroinvertebrate communities of five springs in the northern Chihuahuan Desert of west Texas and south‐eastern New Mexico were sampled seasonally. Rather than focusing on individual taxa, this study examined the community structure of springs to identify patterns that are likely to reflect both local conditions and potential dispersal barriers. 3. In total, 46 774 individuals representing 109 taxa were collected with high relative abundances of gastropods, amphipods, and oligochaetes. Spatial variation in community composition was greater than temporal variation. 4. Although there were differences in the salinity content and concentrations of several major anions and cations among sites, these were not significant predictors of difference in community structure. Two springs sharing the same groundwater source contained similar macroin-vertebrate communities and had similar physicochemical conditions. Results from this study suggest that springs in the northern Chihuahuan Desert contain unique communities and endemic species owing to historical processes such as isolation and dispersal limitation, rather than contemporary processes such as environmental filtering and species sorting. 5. Springs located in the northern Chihuahuan Desert, like those located in other arid regions of the world, are valuable for their biodiversity because of their distinct invertebrate communities and high rates of endemism. Thus, they should be conserved individually to ensure the preservation of unique species and communities.
In the face of global climate change, organisms may respond to temperature increases by shifting ... more In the face of global climate change, organisms may respond to temperature increases by shifting their ranges poleward or to higher altitudes. However, the direction of range shifts in riverine systems is less clear. Because rivers are dendritic networks, there is only one dispersal route from any given location to another. Thus, range shifts are only possible if branches are connected by suitable habitat, and stream-dwelling organisms can disperse through these branches. We used Cumberlandia monodonta (Bivalvia: Unionoida: Margaritiferidae) as a model species to investigate the effects of climate change on population connectivity because a majority of contemporary populations are panmictic. We combined ecological niche models (ENMs) with population genetic simulations to investigate the effects of climate change on population connectivity and genetic diversity of C. monodonta. The ENMs were constructed using bioclimatic and landscape data to project shifts in suitable habitat under...
ABSTRACT Climate change and human population growth threaten the supply of fresh water for human ... more ABSTRACT Climate change and human population growth threaten the supply of fresh water for human use and freshwater biodiversity. Long-term studies are necessary to identify the effects of such temporal trends on biological and ecological phenomena; however, the collection of long-term data can be costly and time-consuming. We investigated the effect of hydrological variation over time on population dynamics in a perennial river of the northern Chihuahuan Desert, using an imperilled freshwater mussel (Popenaias popeii) as a model. We conducted a 15-year mark-and-recapture study, and distance sampling, to estimate demographic parameters while accounting for habitat heterogeneity and changes in river discharge. Recapture probability varied between microhabitats, and survival was positively correlated with river discharge. Survival and the finite rate of population growth were relatively stable over time. Over 60% of individuals were found at relatively high density in riffle habitats, which compose c. 16% of the total study area. Mean monthly temperature in the region increased over the past 100 years, and mean monthly discharge of the Black River declined over the past 65 years. With no significant trends in total monthly precipitation, declines in discharge suggest that reduction of stream flow is likely due to lowering of the water table and decreased groundwater recharge. Significant changes in climate and hydrological regimes, and increases in anthropogenic threats (increased water demand, degraded water quality) in the region, may induce significant declines in population size of this imperilled mussel. We demonstrated the importance of considering habitat heterogeneity and hydrological cycles over time to examine population dynamics. Survival of benthic invertebrates in desert streams is sensitive to hydrological cycles, which are expected to be altered via climate change and extensive water use. Species recovery plans need to incorporate knowledge of spatial distributions when designing strategies for habitat assessment and making conservation decisions.
Historical-to-recent climate change and anthropogenic disturbance affect species distributions an... more Historical-to-recent climate change and anthropogenic disturbance affect species distributions and genetic structure. The Rio Grande watershed of the United States and Mexico encompasses ecosystems that are intensively exploited, resulting in substantial degradation of aquatic habitats. While significant anthropogenic disturbances in the Rio Grande are recent, inhospitable conditions for freshwater organisms likely existed prior to such disturbances. A combination of anthropogenic and past climate factors may contribute to current distributions of aquatic fauna in the Rio Grande basin. We used mitochondrial DNA and 18 microsatellite loci to infer evolutionary history and genetic structure of an endangered freshwater mussel, Popenaias popeii, throughout the Rio Grande drainage. We estimated spatial connectivity and gene flow across extant populations of P. popeii and used ecological niche models (ENMs) and approximate Bayesian computation (ABC) to infer its evolutionary history durin...
The predaceous cladoceran, Bythotrephes cederstroemi (Schoedler 1877), was first noted in the Gre... more The predaceous cladoceran, Bythotrephes cederstroemi (Schoedler 1877), was first noted in the Great Lakes in late 1984, and had spread to Lakes Huron, Erie, Ontario, and Michigan by late summer of 1986. Zooplankton samples collected from Batchawana Bay, Lake Superior on 15 September 1988 contained large numbers of B. cederstroemi (122.8 individuals/m 2 ). Geographic variation in Great Lakes B.
Uploads