Daniel Hornbach | Macalester College (original) (raw)

Papers by Daniel Hornbach

Hydrobiologia, 1984

The effects of particle concentration and season on the filtration rates of the freshwater clam S... more The effects of particle concentration and season on the filtration rates of the freshwater clam Sphaerium striatinum Lamarck were assessed by measuring clearance rates of small (2.02 µm) latex beads from dilute suspensions. Filtration rates decreased as particle ...

Water, May 20, 2020

Small ponds constitute a significant number of standing water bodies on earth and may contribute ... more Small ponds constitute a significant number of standing water bodies on earth and may contribute to CO 2 uptake or release into the atmosphere. Despite their importance, few studies have examined ecosystem metabolism in ponds, especially in ponds that may be dominated by floating-leaved macrophytes. In this study, we examined ecosystem metabolism by measuring changes in dissolved oxygen levels every 10 min from late May through late October for four shallow ponds (0.5-1.5 m) in east-central Minnesota, USA. Ponds had varying levels of floating-leaved macrophytes from sparse (<1% coverage) to abundant (61% coverage). We found significant differences in a number of physical/chemical factors including P, N, DOC, water temperature and light penetration. We also found significant difference in gross primary production (GPP-average ranged from 2.2 to 5.5 mg O 2 /L/day), respiration (R-average ranged from −6.8 to −3.6 mg O 2 /L/day) and net ecosystem production (NEP-average ranged from −1.5 to −0.1 mg O 2 /L/day) among the ponds. On average, all of the ponds were heterotrophic (R > GPP). While it appeared that floating-leaved macrophytes provided a significant impact on ecosystem metabolism, there was not a one-to-one correspondence between the amount of macrophytes and the level of ecosystem metabolism.

Journal of The North American Benthological Society, Sep 1, 1998

Page 1. JN Am. Benthol. Soc., 1998, 17(3):301-310 ? 1998 by The North American Benthological Soci... more Page 1. JN Am. Benthol. Soc., 1998, 17(3):301-310 ? 1998 by The North American Benthological Society Selective predation by muskrats on freshwater mussels in 2 Minnesota rivers MEGAN TYRRELL1 AND DANIEL J. HORNBACH2 ...

Malacological review, 1992

... Titre du document / Document title. Species composition of the mussel assemblages in the uppe... more ... Titre du document / Document title. Species composition of the mussel assemblages in the upper Mississippi River. Auteur(s) / Author(s). HORNBACH DJ ; MILLER AC ; PAYNE BS ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). Macalester coll., dep. biology, St. ...

Hydrobiologia, Feb 1, 1993

The temporal and spatial variability in the midge assemblage found in a backwater lake of the Mis... more The temporal and spatial variability in the midge assemblage found in a backwater lake of the Mississippi River was examined. Biweekly samples were taken during the summers of 1987 and 1988. Four taxa of chironomids were found. The population density and sizes of chironomids, and the proportion that each taxon comprised of the midge assemblage, varied significantly in time and space. In an attempt to examine whether the variability noted was related to sediment accretion in the lake, sedimentation rates were measured. There were few correlations among sedimentation rate or the organic matter content of the collected sediment and the structure of the midge assemblage. Those few correlations that were statistically significant were low and often paradoxical. For example negative relationships were found between the density and size of Chironomus spp., a detritivore, and the amount of sediment deposited or its organic matter content. Also no significant relationships were found between the density of the predator Cryptochironomus spp. and the density of other chironomids (potential prey). These negative findings indicate that factors other than food, such as sediment texture, may be more important than food availability in structuring chironomid assemblages in backwater areas. There was spatial variability in the densities and sizes of chironomids that may be explained by differences in sediment texture and organic matter. This suggests that short-term inputs of sediment (as ascertained by sediment traps) may not greatly influence midge assemblages while the long-term changes in sediment composition may have large influences.

Springer eBooks, 2001

Page 1. 12 Macrohabitat Factors Influencing the Distribution of Naiads in the St. Croix River, Mi... more Page 1. 12 Macrohabitat Factors Influencing the Distribution of Naiads in the St. Croix River, Minnesota and Wisconsin, USA DANIEL J. HORNBACH 12.1 Introduction Freshwater mussels (superfamily Unioniacea) are widely ...

Ohio Journal of Science, Sep 29, 1978

Hydrobiologia, Aug 29, 2019

Journal of Parasitology, Jun 1, 1979

In June, 6.7% of adult Succinea ovalis collected near Urbana, Ohio, were infected with the tremat... more In June, 6.7% of adult Succinea ovalis collected near Urbana, Ohio, were infected with the trematode, Leucochloridium variae. The effects of parasitism were assessed as total organic carbon (equivalent to calorific values) and as total nitrogen. The parasite represents 23.8% of total (parasite + snail tissue) dry tissue weight, 21.4% of total carbon and 19.8% of total nitrogen of infected snails. The higher C:N ratio for parasite tissue indicates a higher proportion of nonproteinaceous compounds (e.g., fats and/or carbohydrates) as compared to host tissue. There is less snail tissue in parasitized S. ovalis. The C:N ratios for parasitized and nonparasitized snail tissue suggest identical percentage compositions of proteins, fats, and carbohydrates.

Aquatic Conservation-marine and Freshwater Ecosystems, Jul 21, 2019

1. Intensive agricultural land use may have adverse impacts on freshwater mussel assemblages. 2. ... more 1. Intensive agricultural land use may have adverse impacts on freshwater mussel assemblages. 2. Before European settlement, the Minnesota River Basin (MRB) was home to dense and diverse assemblages of freshwater mussels. Of the 40 species that occurred there, 43% have been extirpated. the St. Croix Basin (SCB) in Minnesota/Wisconsin, in contrast, has maintained a dense and diverse mussel assemblage, probably owing to the maintenance of a higher-quality ecosystem. 3. Mussels were sampled in four rivers representing an agricultural land-use gradient.

Journal of Freshwater Ecology, Dec 1, 1989

Page 1. Benthic Macroinvertebrate Community Structure in a Backwater Lake of Pool 2, Upper Missis... more Page 1. Benthic Macroinvertebrate Community Structure in a Backwater Lake of Pool 2, Upper Mississlppl River Daniel J. Hornbach and Tony Deneka Department of Biology Macalester College St. Paul, MN 55105 and Barry ...

Hydrobiologia, Jul 31, 2019

Freshwater mussels face threats from climate change and changing land use that are dramatically a... more Freshwater mussels face threats from climate change and changing land use that are dramatically altering their habitat. The health of mussel populations and the state of current and past environmental conditions can be monitored by measuring mussel growth and glycogen levels. In this study, we measured growth and glycogen levels in mussels from two small river basins impacted by different land uses. The Snake River in the St. Croix Basin, Minnesota, had low levels of suspended sediments and was surrounded mostly by forest and some developed land. The Chippewa, Cottonwood, and Le Sueur rivers in the Minnesota River Basin had significantly higher annual suspended sediment loads and highly agricultural basins. Mussel growth was highest in the Le Sueur and Cottonwood rivers followed by the Chippewa and the Snake rivers. Mussels in the Minnesota Basin rivers all had higher mussel foot glycogen concentrations than the Snake River. These patterns were similar for two mussel species, suggesting that environmental conditions are likely determining levels of growth. Although agriculture had a negative effect on mussel population abundance and diversity, it had a positive effect on growth and glycogen levels.

The American Naturalist, Jul 1, 1981

Canadian Journal of Zoology, Dec 1, 1984

An annual energy budget was constructed for a stream population of Sphaerium striatinum. The annu... more An annual energy budget was constructed for a stream population of Sphaerium striatinum. The annual productivity (P) was 2.79 g C∙m−2∙year−1 and the average standing crop biomass (B) was 0.58 g C∙m−2; the resulting annual P:B ratio of 4.58 is below that expected for a bivoltine animal. The low value for reproductive effort (Re:P = 16.1%) may partially be attributed to the ovoviviparous, iteroparous nature of this population. A strategy of partitioning a large proportion of production to growth (G:P = 83.9%) may insure a high probability of attaining the minimum size necessary for reproduction. Production accounts for 44% of assimilation (A) with 56% of A lost through respiration. The net production efficiency (P:A = 44%) is high and indicates that this population is efficient in partitioning energy to growth and reproduction. The population must consume (C) 10.57 g C∙m−2∙year−1 to meet its energy needs. Only 35% of this could be accounted for by filter feeding; the remainder may have come from deposit feeding. Comparisons of P, P:B, Re:P and P:A with published values for corbiculacean clams indicates that this population of S. striatinum is one of the most productive and efficient in its energy partitioning of populations studied to date.

Journal of The North American Benthological Society, Dec 1, 1986

Page 1. JN Am. Benthol. Soc., 1986, 5(4):263-271 ? 1986 by The North American Benthological Socie... more Page 1. JN Am. Benthol. Soc., 1986, 5(4):263-271 ? 1986 by The North American Benthological Society Life-history variation in a stream population of Musculium partumeium (Bivalvia:Pisidiidae) DANIEL J. HORNBACH1 AND ...

Aquatic Conservation-marine and Freshwater Ecosystems, May 1, 2010

is a globally important centre of freshwater mussel biodiversity. Accurate population estimates a... more is a globally important centre of freshwater mussel biodiversity. Accurate population estimates and descriptions of critical habitat for endangered species of mussels are needed but are hindered by their patchy distribution and the dynamic nature of their habitat. Adaptive cluster sampling (ACS) was used to estimate population size and habitat associations of two federally endangered species, Higgins eye (Lampsilis higginsii) and winged mapleleaf (Quadrula fragosa), in the St. Croix River. 2. This river holds the largest known winged mapleleaf population in the upper Mississippi River and contains Essential Habitat Areas for Higgins eye. Winged mapleleaf density ranged from 0.008-0.020 individuals m À2 (coefficient of variation 5 50-66%), yielding an estimate of 13 000 winged mapleleaf in this reach of the river. Higgins eye density varied from 0.008-0.015 individuals m À2 (coefficient of variation 5 66-167%) giving an estimate of 14 400 individuals in this area. 3. Higgins eye and winged mapleleaf were associated with areas of the overall highest mussel density and species richness, suggesting these endangered species occur in 'premier' mussel habitat. There were no differences in many microhabitat factors for sites with and without either endangered species. Select hydraulic measures (such as shear velocity and shear stress) showed significant differences in areas with and without the winged mapleleaf but not for Higgins eye. Areas that are less depositional support dense and diverse mussel assemblages that include both endangered species, with winged mapleleaf having a narrower habitat range than Higgins eye. 4. This study suggests that ACS can provide statistically robust estimates of density with 2-3 times more efficiency than simple random sampling. ACS, however, was quite time consuming. This work confirmed that of others demonstrating that larger-scale hydraulic parameters might be better predictors of prime mussel habitat than fine-scaled microhabitat factors. Using hydraulic measures may allow improved identification of potentially critical mussel habitat.

Hydrobiologia, 1984

The effects of particle concentration and season on the filtration rates of the freshwater clam S... more The effects of particle concentration and season on the filtration rates of the freshwater clam Sphaerium striatinum Lamarck were assessed by measuring clearance rates of small (2.02 µm) latex beads from dilute suspensions. Filtration rates decreased as particle ...

Oecologia, 1980

Reproduction was studied in two populations ofMusculium partumeium from temporary and permanent p... more Reproduction was studied in two populations ofMusculium partumeium from temporary and permanent ponds. Adults of the single annual generation from the ephemeral pond have an annual selection ratio of 25:1 with 37.03 μgC per newborn, and an intrinsic rate of increase (r) of 0.0084 day(-1). Fall-born adults from the permanent pond have an annual selection ratio of 38:1, 21.82 μgC per newborn and anr of 0.0115 day(-1); springborn adults have an annual selection ratio of 136:1 (107:1 for their contribution to fall birth and 29:1 for the spring birth period) with newborns of 24.21 μgC and anr of 0.0304. The trade off between quantity and quality of young is discussed in terms of adaptive strategies.

Hydrobiologia, 1984

The effects of particle concentration and season on the filtration rates of the freshwater clam S... more The effects of particle concentration and season on the filtration rates of the freshwater clam Sphaerium striatinum Lamarck were assessed by measuring clearance rates of small (2.02 µm) latex beads from dilute suspensions. Filtration rates decreased as particle ...

Water, May 20, 2020

Small ponds constitute a significant number of standing water bodies on earth and may contribute ... more Small ponds constitute a significant number of standing water bodies on earth and may contribute to CO 2 uptake or release into the atmosphere. Despite their importance, few studies have examined ecosystem metabolism in ponds, especially in ponds that may be dominated by floating-leaved macrophytes. In this study, we examined ecosystem metabolism by measuring changes in dissolved oxygen levels every 10 min from late May through late October for four shallow ponds (0.5-1.5 m) in east-central Minnesota, USA. Ponds had varying levels of floating-leaved macrophytes from sparse (<1% coverage) to abundant (61% coverage). We found significant differences in a number of physical/chemical factors including P, N, DOC, water temperature and light penetration. We also found significant difference in gross primary production (GPP-average ranged from 2.2 to 5.5 mg O 2 /L/day), respiration (R-average ranged from −6.8 to −3.6 mg O 2 /L/day) and net ecosystem production (NEP-average ranged from −1.5 to −0.1 mg O 2 /L/day) among the ponds. On average, all of the ponds were heterotrophic (R > GPP). While it appeared that floating-leaved macrophytes provided a significant impact on ecosystem metabolism, there was not a one-to-one correspondence between the amount of macrophytes and the level of ecosystem metabolism.

Journal of The North American Benthological Society, Sep 1, 1998

Page 1. JN Am. Benthol. Soc., 1998, 17(3):301-310 ? 1998 by The North American Benthological Soci... more Page 1. JN Am. Benthol. Soc., 1998, 17(3):301-310 ? 1998 by The North American Benthological Society Selective predation by muskrats on freshwater mussels in 2 Minnesota rivers MEGAN TYRRELL1 AND DANIEL J. HORNBACH2 ...

Malacological review, 1992

... Titre du document / Document title. Species composition of the mussel assemblages in the uppe... more ... Titre du document / Document title. Species composition of the mussel assemblages in the upper Mississippi River. Auteur(s) / Author(s). HORNBACH DJ ; MILLER AC ; PAYNE BS ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). Macalester coll., dep. biology, St. ...

Hydrobiologia, Feb 1, 1993

The temporal and spatial variability in the midge assemblage found in a backwater lake of the Mis... more The temporal and spatial variability in the midge assemblage found in a backwater lake of the Mississippi River was examined. Biweekly samples were taken during the summers of 1987 and 1988. Four taxa of chironomids were found. The population density and sizes of chironomids, and the proportion that each taxon comprised of the midge assemblage, varied significantly in time and space. In an attempt to examine whether the variability noted was related to sediment accretion in the lake, sedimentation rates were measured. There were few correlations among sedimentation rate or the organic matter content of the collected sediment and the structure of the midge assemblage. Those few correlations that were statistically significant were low and often paradoxical. For example negative relationships were found between the density and size of Chironomus spp., a detritivore, and the amount of sediment deposited or its organic matter content. Also no significant relationships were found between the density of the predator Cryptochironomus spp. and the density of other chironomids (potential prey). These negative findings indicate that factors other than food, such as sediment texture, may be more important than food availability in structuring chironomid assemblages in backwater areas. There was spatial variability in the densities and sizes of chironomids that may be explained by differences in sediment texture and organic matter. This suggests that short-term inputs of sediment (as ascertained by sediment traps) may not greatly influence midge assemblages while the long-term changes in sediment composition may have large influences.

Springer eBooks, 2001

Page 1. 12 Macrohabitat Factors Influencing the Distribution of Naiads in the St. Croix River, Mi... more Page 1. 12 Macrohabitat Factors Influencing the Distribution of Naiads in the St. Croix River, Minnesota and Wisconsin, USA DANIEL J. HORNBACH 12.1 Introduction Freshwater mussels (superfamily Unioniacea) are widely ...

Ohio Journal of Science, Sep 29, 1978

Hydrobiologia, Aug 29, 2019

Journal of Parasitology, Jun 1, 1979

In June, 6.7% of adult Succinea ovalis collected near Urbana, Ohio, were infected with the tremat... more In June, 6.7% of adult Succinea ovalis collected near Urbana, Ohio, were infected with the trematode, Leucochloridium variae. The effects of parasitism were assessed as total organic carbon (equivalent to calorific values) and as total nitrogen. The parasite represents 23.8% of total (parasite + snail tissue) dry tissue weight, 21.4% of total carbon and 19.8% of total nitrogen of infected snails. The higher C:N ratio for parasite tissue indicates a higher proportion of nonproteinaceous compounds (e.g., fats and/or carbohydrates) as compared to host tissue. There is less snail tissue in parasitized S. ovalis. The C:N ratios for parasitized and nonparasitized snail tissue suggest identical percentage compositions of proteins, fats, and carbohydrates.

Aquatic Conservation-marine and Freshwater Ecosystems, Jul 21, 2019

1. Intensive agricultural land use may have adverse impacts on freshwater mussel assemblages. 2. ... more 1. Intensive agricultural land use may have adverse impacts on freshwater mussel assemblages. 2. Before European settlement, the Minnesota River Basin (MRB) was home to dense and diverse assemblages of freshwater mussels. Of the 40 species that occurred there, 43% have been extirpated. the St. Croix Basin (SCB) in Minnesota/Wisconsin, in contrast, has maintained a dense and diverse mussel assemblage, probably owing to the maintenance of a higher-quality ecosystem. 3. Mussels were sampled in four rivers representing an agricultural land-use gradient.

Journal of Freshwater Ecology, Dec 1, 1989

Page 1. Benthic Macroinvertebrate Community Structure in a Backwater Lake of Pool 2, Upper Missis... more Page 1. Benthic Macroinvertebrate Community Structure in a Backwater Lake of Pool 2, Upper Mississlppl River Daniel J. Hornbach and Tony Deneka Department of Biology Macalester College St. Paul, MN 55105 and Barry ...

Hydrobiologia, Jul 31, 2019

Freshwater mussels face threats from climate change and changing land use that are dramatically a... more Freshwater mussels face threats from climate change and changing land use that are dramatically altering their habitat. The health of mussel populations and the state of current and past environmental conditions can be monitored by measuring mussel growth and glycogen levels. In this study, we measured growth and glycogen levels in mussels from two small river basins impacted by different land uses. The Snake River in the St. Croix Basin, Minnesota, had low levels of suspended sediments and was surrounded mostly by forest and some developed land. The Chippewa, Cottonwood, and Le Sueur rivers in the Minnesota River Basin had significantly higher annual suspended sediment loads and highly agricultural basins. Mussel growth was highest in the Le Sueur and Cottonwood rivers followed by the Chippewa and the Snake rivers. Mussels in the Minnesota Basin rivers all had higher mussel foot glycogen concentrations than the Snake River. These patterns were similar for two mussel species, suggesting that environmental conditions are likely determining levels of growth. Although agriculture had a negative effect on mussel population abundance and diversity, it had a positive effect on growth and glycogen levels.

The American Naturalist, Jul 1, 1981

Canadian Journal of Zoology, Dec 1, 1984

An annual energy budget was constructed for a stream population of Sphaerium striatinum. The annu... more An annual energy budget was constructed for a stream population of Sphaerium striatinum. The annual productivity (P) was 2.79 g C∙m−2∙year−1 and the average standing crop biomass (B) was 0.58 g C∙m−2; the resulting annual P:B ratio of 4.58 is below that expected for a bivoltine animal. The low value for reproductive effort (Re:P = 16.1%) may partially be attributed to the ovoviviparous, iteroparous nature of this population. A strategy of partitioning a large proportion of production to growth (G:P = 83.9%) may insure a high probability of attaining the minimum size necessary for reproduction. Production accounts for 44% of assimilation (A) with 56% of A lost through respiration. The net production efficiency (P:A = 44%) is high and indicates that this population is efficient in partitioning energy to growth and reproduction. The population must consume (C) 10.57 g C∙m−2∙year−1 to meet its energy needs. Only 35% of this could be accounted for by filter feeding; the remainder may have come from deposit feeding. Comparisons of P, P:B, Re:P and P:A with published values for corbiculacean clams indicates that this population of S. striatinum is one of the most productive and efficient in its energy partitioning of populations studied to date.

Journal of The North American Benthological Society, Dec 1, 1986

Page 1. JN Am. Benthol. Soc., 1986, 5(4):263-271 ? 1986 by The North American Benthological Socie... more Page 1. JN Am. Benthol. Soc., 1986, 5(4):263-271 ? 1986 by The North American Benthological Society Life-history variation in a stream population of Musculium partumeium (Bivalvia:Pisidiidae) DANIEL J. HORNBACH1 AND ...

Aquatic Conservation-marine and Freshwater Ecosystems, May 1, 2010

is a globally important centre of freshwater mussel biodiversity. Accurate population estimates a... more is a globally important centre of freshwater mussel biodiversity. Accurate population estimates and descriptions of critical habitat for endangered species of mussels are needed but are hindered by their patchy distribution and the dynamic nature of their habitat. Adaptive cluster sampling (ACS) was used to estimate population size and habitat associations of two federally endangered species, Higgins eye (Lampsilis higginsii) and winged mapleleaf (Quadrula fragosa), in the St. Croix River. 2. This river holds the largest known winged mapleleaf population in the upper Mississippi River and contains Essential Habitat Areas for Higgins eye. Winged mapleleaf density ranged from 0.008-0.020 individuals m À2 (coefficient of variation 5 50-66%), yielding an estimate of 13 000 winged mapleleaf in this reach of the river. Higgins eye density varied from 0.008-0.015 individuals m À2 (coefficient of variation 5 66-167%) giving an estimate of 14 400 individuals in this area. 3. Higgins eye and winged mapleleaf were associated with areas of the overall highest mussel density and species richness, suggesting these endangered species occur in 'premier' mussel habitat. There were no differences in many microhabitat factors for sites with and without either endangered species. Select hydraulic measures (such as shear velocity and shear stress) showed significant differences in areas with and without the winged mapleleaf but not for Higgins eye. Areas that are less depositional support dense and diverse mussel assemblages that include both endangered species, with winged mapleleaf having a narrower habitat range than Higgins eye. 4. This study suggests that ACS can provide statistically robust estimates of density with 2-3 times more efficiency than simple random sampling. ACS, however, was quite time consuming. This work confirmed that of others demonstrating that larger-scale hydraulic parameters might be better predictors of prime mussel habitat than fine-scaled microhabitat factors. Using hydraulic measures may allow improved identification of potentially critical mussel habitat.

Hydrobiologia, 1984

The effects of particle concentration and season on the filtration rates of the freshwater clam S... more The effects of particle concentration and season on the filtration rates of the freshwater clam Sphaerium striatinum Lamarck were assessed by measuring clearance rates of small (2.02 µm) latex beads from dilute suspensions. Filtration rates decreased as particle ...

Oecologia, 1980

Reproduction was studied in two populations ofMusculium partumeium from temporary and permanent p... more Reproduction was studied in two populations ofMusculium partumeium from temporary and permanent ponds. Adults of the single annual generation from the ephemeral pond have an annual selection ratio of 25:1 with 37.03 μgC per newborn, and an intrinsic rate of increase (r) of 0.0084 day(-1). Fall-born adults from the permanent pond have an annual selection ratio of 38:1, 21.82 μgC per newborn and anr of 0.0115 day(-1); springborn adults have an annual selection ratio of 136:1 (107:1 for their contribution to fall birth and 29:1 for the spring birth period) with newborns of 24.21 μgC and anr of 0.0304. The trade off between quantity and quality of young is discussed in terms of adaptive strategies.