and Mass Communications and the Lincoln Journal Star began collaborating to report on the Platte ... more and Mass Communications and the Lincoln Journal Star began collaborating to report on the Platte River. This unique project involved 19 students from the college's science-writing, graphics, editing and photography classes, as well as reporters, artists and a photographer from the Journal Star. Journal Star reporters covered water policy, while the students focused most of their work on science related to the Platte. About evenly divided between majors in science and journalism, the students learned about Platte River issues as they reported and wrote their stories. The team interviewed dozens of farmers, scientists and local, state and federal officials. Students watched the great spectacle of spring migration in the central Platte valley, walked through irrigated corn with farmers and sat through a session of the Nebraska Supreme Court as it considered a landmark case centered on the Platte. Two dozen stories published over a year's time in the Journal Star informed and educated readers about efforts to manage and protect water in the Platte River basin. This report collects and updates those stories and supplements them with vivid photography and graphics. It describes the resources of the basin and explores how the people and the wildlife who live there have used them. It explains the history and nature of conflicts over those resources and examines the troubled collaboration among science, policy and law in efforts to resolve those conflicts. This report will provide a lasting resource to help readers see the Platte River as more than an attractive feature in the landscape and in much more detail than is possible from the air or from an Interstate 80 bridge. "Platte River Odyssey" will provide solid background for a dynamic story that will continue to develop even after the drought is over.
Ants are highly influential organisms in terrestrial ecosystems, including the tallgrass prairie,... more Ants are highly influential organisms in terrestrial ecosystems, including the tallgrass prairie, one of the most endangered ecosystems in North America. Through their tunneling, ants affect soil properties and resource availability for animals and plants. Ants also have important ecological roles as consumers of plant tissue and seeds. In the last several decades, various organizations, agencies, and agricultural producers have attempted to create wildlife habitat or reduce soil erosion by seeding thousands of hectares of bare cropland in the central United States with tallgrass prairie seed mixes. Although initially, monitoring of these restorations and of unplowed prairie remnants focused on plants and birds, in recent years the response of invertebrates such as ants has increasingly been the subject of research. An understanding of tallgrass prairie ant communities can help land managers and scientists better monitor the ecological condition of tallgrass prairie and guide management and restoration efforts. Here I review our current knowledge of ant species found within tallgrass prairie, their ecological roles, and their response to management.
Although several frameworks for assessing the resilience of social-ecological systems (SESs) have... more Although several frameworks for assessing the resilience of social-ecological systems (SESs) have been developed, some practitioners may not have sufficient time and information to conduct extensive resilience assessments. We have presented a simplified approach to resilience assessment that reviews the scientific, historical, and social literature to rate the resilience of an SES with respect to nine resilience properties: ecological variability, diversity, modularity, acknowledgement of slow variables, tight feedbacks, social capital, innovation, overlap in governance, and ecosystem services. We evaluated the effects of two large-scale projects, the construction of a major dam and the implementation of an ecosystem recovery program, on the resilience of the central Platte River SES (Nebraska, United States). We used this case study to identify the strengths and weaknesses of applying a simplified approach to resilience assessment. Although social resilience has increased steadily since the predam period for the central Platte River SES, ecological resilience was greatly reduced in the postdam period as compared to the predam and ecosystem recovery program time periods.
In recent decades, agricultural producers and non-governmental organizations have restored thousa... more In recent decades, agricultural producers and non-governmental organizations have restored thousands of hectares of former cropland in the central United States with native grasses and forbs. However, the ability of these grassland restorations to attract predatory invertebrates has not been well documented, even though predators provide an important ecosystem service to agricultural producers by naturally regulating herbivores. This study assessed the effects of plant richness and seeding density on the richness and abundance of surface-dwelling (ants, ground beetles, and spiders) and aboveground (ladybird beetles) predatory invertebrates. In the spring of 2006, twenty-four 55 m × 55 m-plots were planted to six replicates in each of four treatments: high richness (97 species typically planted by The Nature Conservancy), at low and high seeding densities, and low richness (15 species representing a typical Natural Resources Conservation Service Conservation Reserve Program mix, CP25), at low and high seeding densities. Ants, ground beetles, and spiders were sampled using pitfall traps and ladybird beetles were sampled using sweep netting in 2007-2009. The abundance of ants, ground beetles, and spiders showed no response to seed mix richness or seeding density but there was a significant positive effect of richness on ladybird beetle abundance. Seeding density had a significant positive effect on ground beetle and spider species richness and Shannon-Weaver diversity. These results may be related to differences in the plant species composition and relative amount of grass basal cover among the treatments rather than richness.
In recent years, agricultural producers and non-governmental organizations and agencies have rest... more In recent years, agricultural producers and non-governmental organizations and agencies have restored thousands of hectares of cropland to grassland in the Great Plains of the United States. However, little is known about the relationships between richness and seeding density in these restorations and resistance to invasive plant species. We assessed the effects of richness and seeding density on resistance to invasive and other unseeded plant species in experimental taligrass prairie plots in central Nebraska. In 2006, twenty-four 55 m x 55 m plots were planted with six replicates in each of four treatments: high richness (97 species typically planted by The Nature Conservancy), at low and high seeding densities, and low richness (15 species representing a typical Conservation Reserve Program mix, CP25), at low and high seeding densities. There was a significant negative relationship between richness and basal cover of unseeded perennial forbs/legumes and unseeded perennial/annual grasses, abundance of bull thistle (Cirsium vulgäre), and the number of inflorescences removed from smooth brome (Bromus inermis) transplants. Invasion resistance may have been higher in the high richness treatments because of the characteristics of the dominant species in these plots or because of greater interspecific competition for limiting resources among forbs/legumes with neighboring plants belonging to the same functional group. Seeding density was not important in affecting invasion resistance, except in the cover of unseeded grasses. Increasing seed mix richness may be more effective than increasing the seeding density for decreasing invasion by unseeded perennial species, bull thistle, and smooth brome.
In recent years, geographic information systems (GIS) have become a powerful tool for mapping and... more In recent years, geographic information systems (GIS) have become a powerful tool for mapping and assessing the provision of ecosystem services within a landscape. GIS can help land managers and conservationists visualize spatial and temporal patterns and changes in ecosystem services and estimate the potential impact from projected changes in land use or management or climatic conditions on the provision of these services. The endgoal of ecosystem service assessment is usually to estimate marginal values of ecosystem services to inform decisions where trade-offs in ecosystem service provision will affect human well-being. Because our ability to estimate the provision of ecosystem services underlies our ability to estimate their societal values, the theoretical bases of GIS approaches and models for assessing ecosystem services need to be well understood before they are employed for decision-making purposes. This paper reviews GIS approaches and software developed for the assessment of ecosystem services and highlights their strengths and weaknesses in the context of different end uses.
The Chinese mystery snail (Bellamya chinensis) is an aquatic invasive species in North America. L... more The Chinese mystery snail (Bellamya chinensis) is an aquatic invasive species in North America. Little is known regarding this species' impacts on freshwater ecosystems. It is believed that population densities can be high, yet no population estimates have been reported. We utilized a mark-recapture approach to generate a population estimate for Chinese mystery snail in Wild Plum Lake, a 6.47-ha reservoir in southeast Nebraska. We calculated, using bias-adjusted Lincoln-Petersen estimation, that there were approximately 664 adult snails within a 127 m 2 transect (5.2 snails/m 2 ). If this density was consistent throughout the littoral zone (<3 m in depth) of the reservoir, then the total adult population in this impoundment is estimated to be 253,570 snails, and the total Chinese mystery snail wet biomass is estimated to be 3,119 kg (643 kg/ha). If this density is confined to the depth sampled in this study (1.46 m), then the adult population is estimated to be 169,400 snails, and wet biomass is estimated to be 2,084 kg (643 kg/ha). Additional research is warranted to further test the utility of mark-recapture methods for aquatic snails and to better understand Chinese mystery snail distributions within reservoirs.
Aboveground Hemiptera and Orthoptera communities were compared among three native and three resto... more Aboveground Hemiptera and Orthoptera communities were compared among three native and three restored mesic tallgrass prairies along the Platte River in central Nebraska to assess both the relative success of restored sites and the relationship between insect and plant communities. Hemiptera and Orthoptera were sampled using sweep nets in early June, mid-July, and mid-August 2000. Plant species composition was assessed in early June and mid-August. A total of 89 Auchenorrhyncha (71 Cicadellidae, 15 Fulgoroidea, and 3 Membracidae) and 23 orthopterans (15 Acrididae and 8 Tettigoniidae) were collected. Eighty-five plant species were observed in combined study sites. Shannon diversity was significantly higher at restored prairie for Cicadellidae (H9 ¼ 1.38), Fulgoroidea (H9 ¼ 0.796), and Membracidae (H9 ¼ 0.290), which comprised the majority of individual insects collected, but significantly higher at native prairie for Acrididae (H9 ¼ 0.560) and Tettigoniidae (H9 ¼ 0.480) (p • 0.05). Species richness was comparable except for Acrididae which were significantly higher in restored prairie. Density of insects generally followed species diversity but was only significantly higher in restored areas for Membracidae. The number of remnantdependent species collected was comparable for both native prairie (n ¼ 15) and restored prairie (n ¼ 15). These results suggest that, at least for Hemiptera, differences in insect communities between native and restored prairie may best be explained by the presence of insect host plants rather than by whether a site is native or restored.
and Mass Communications and the Lincoln Journal Star began collaborating to report on the Platte ... more and Mass Communications and the Lincoln Journal Star began collaborating to report on the Platte River. This unique project involved 19 students from the college's science-writing, graphics, editing and photography classes, as well as reporters, artists and a photographer from the Journal Star. Journal Star reporters covered water policy, while the students focused most of their work on science related to the Platte. About evenly divided between majors in science and journalism, the students learned about Platte River issues as they reported and wrote their stories. The team interviewed dozens of farmers, scientists and local, state and federal officials. Students watched the great spectacle of spring migration in the central Platte valley, walked through irrigated corn with farmers and sat through a session of the Nebraska Supreme Court as it considered a landmark case centered on the Platte. Two dozen stories published over a year's time in the Journal Star informed and educated readers about efforts to manage and protect water in the Platte River basin. This report collects and updates those stories and supplements them with vivid photography and graphics. It describes the resources of the basin and explores how the people and the wildlife who live there have used them. It explains the history and nature of conflicts over those resources and examines the troubled collaboration among science, policy and law in efforts to resolve those conflicts. This report will provide a lasting resource to help readers see the Platte River as more than an attractive feature in the landscape and in much more detail than is possible from the air or from an Interstate 80 bridge. "Platte River Odyssey" will provide solid background for a dynamic story that will continue to develop even after the drought is over.
Ants are highly influential organisms in terrestrial ecosystems, including the tallgrass prairie,... more Ants are highly influential organisms in terrestrial ecosystems, including the tallgrass prairie, one of the most endangered ecosystems in North America. Through their tunneling, ants affect soil properties and resource availability for animals and plants. Ants also have important ecological roles as consumers of plant tissue and seeds. In the last several decades, various organizations, agencies, and agricultural producers have attempted to create wildlife habitat or reduce soil erosion by seeding thousands of hectares of bare cropland in the central United States with tallgrass prairie seed mixes. Although initially, monitoring of these restorations and of unplowed prairie remnants focused on plants and birds, in recent years the response of invertebrates such as ants has increasingly been the subject of research. An understanding of tallgrass prairie ant communities can help land managers and scientists better monitor the ecological condition of tallgrass prairie and guide management and restoration efforts. Here I review our current knowledge of ant species found within tallgrass prairie, their ecological roles, and their response to management.
Although several frameworks for assessing the resilience of social-ecological systems (SESs) have... more Although several frameworks for assessing the resilience of social-ecological systems (SESs) have been developed, some practitioners may not have sufficient time and information to conduct extensive resilience assessments. We have presented a simplified approach to resilience assessment that reviews the scientific, historical, and social literature to rate the resilience of an SES with respect to nine resilience properties: ecological variability, diversity, modularity, acknowledgement of slow variables, tight feedbacks, social capital, innovation, overlap in governance, and ecosystem services. We evaluated the effects of two large-scale projects, the construction of a major dam and the implementation of an ecosystem recovery program, on the resilience of the central Platte River SES (Nebraska, United States). We used this case study to identify the strengths and weaknesses of applying a simplified approach to resilience assessment. Although social resilience has increased steadily since the predam period for the central Platte River SES, ecological resilience was greatly reduced in the postdam period as compared to the predam and ecosystem recovery program time periods.
In recent decades, agricultural producers and non-governmental organizations have restored thousa... more In recent decades, agricultural producers and non-governmental organizations have restored thousands of hectares of former cropland in the central United States with native grasses and forbs. However, the ability of these grassland restorations to attract predatory invertebrates has not been well documented, even though predators provide an important ecosystem service to agricultural producers by naturally regulating herbivores. This study assessed the effects of plant richness and seeding density on the richness and abundance of surface-dwelling (ants, ground beetles, and spiders) and aboveground (ladybird beetles) predatory invertebrates. In the spring of 2006, twenty-four 55 m × 55 m-plots were planted to six replicates in each of four treatments: high richness (97 species typically planted by The Nature Conservancy), at low and high seeding densities, and low richness (15 species representing a typical Natural Resources Conservation Service Conservation Reserve Program mix, CP25), at low and high seeding densities. Ants, ground beetles, and spiders were sampled using pitfall traps and ladybird beetles were sampled using sweep netting in 2007-2009. The abundance of ants, ground beetles, and spiders showed no response to seed mix richness or seeding density but there was a significant positive effect of richness on ladybird beetle abundance. Seeding density had a significant positive effect on ground beetle and spider species richness and Shannon-Weaver diversity. These results may be related to differences in the plant species composition and relative amount of grass basal cover among the treatments rather than richness.
In recent years, agricultural producers and non-governmental organizations and agencies have rest... more In recent years, agricultural producers and non-governmental organizations and agencies have restored thousands of hectares of cropland to grassland in the Great Plains of the United States. However, little is known about the relationships between richness and seeding density in these restorations and resistance to invasive plant species. We assessed the effects of richness and seeding density on resistance to invasive and other unseeded plant species in experimental taligrass prairie plots in central Nebraska. In 2006, twenty-four 55 m x 55 m plots were planted with six replicates in each of four treatments: high richness (97 species typically planted by The Nature Conservancy), at low and high seeding densities, and low richness (15 species representing a typical Conservation Reserve Program mix, CP25), at low and high seeding densities. There was a significant negative relationship between richness and basal cover of unseeded perennial forbs/legumes and unseeded perennial/annual grasses, abundance of bull thistle (Cirsium vulgäre), and the number of inflorescences removed from smooth brome (Bromus inermis) transplants. Invasion resistance may have been higher in the high richness treatments because of the characteristics of the dominant species in these plots or because of greater interspecific competition for limiting resources among forbs/legumes with neighboring plants belonging to the same functional group. Seeding density was not important in affecting invasion resistance, except in the cover of unseeded grasses. Increasing seed mix richness may be more effective than increasing the seeding density for decreasing invasion by unseeded perennial species, bull thistle, and smooth brome.
In recent years, geographic information systems (GIS) have become a powerful tool for mapping and... more In recent years, geographic information systems (GIS) have become a powerful tool for mapping and assessing the provision of ecosystem services within a landscape. GIS can help land managers and conservationists visualize spatial and temporal patterns and changes in ecosystem services and estimate the potential impact from projected changes in land use or management or climatic conditions on the provision of these services. The endgoal of ecosystem service assessment is usually to estimate marginal values of ecosystem services to inform decisions where trade-offs in ecosystem service provision will affect human well-being. Because our ability to estimate the provision of ecosystem services underlies our ability to estimate their societal values, the theoretical bases of GIS approaches and models for assessing ecosystem services need to be well understood before they are employed for decision-making purposes. This paper reviews GIS approaches and software developed for the assessment of ecosystem services and highlights their strengths and weaknesses in the context of different end uses.
The Chinese mystery snail (Bellamya chinensis) is an aquatic invasive species in North America. L... more The Chinese mystery snail (Bellamya chinensis) is an aquatic invasive species in North America. Little is known regarding this species' impacts on freshwater ecosystems. It is believed that population densities can be high, yet no population estimates have been reported. We utilized a mark-recapture approach to generate a population estimate for Chinese mystery snail in Wild Plum Lake, a 6.47-ha reservoir in southeast Nebraska. We calculated, using bias-adjusted Lincoln-Petersen estimation, that there were approximately 664 adult snails within a 127 m 2 transect (5.2 snails/m 2 ). If this density was consistent throughout the littoral zone (<3 m in depth) of the reservoir, then the total adult population in this impoundment is estimated to be 253,570 snails, and the total Chinese mystery snail wet biomass is estimated to be 3,119 kg (643 kg/ha). If this density is confined to the depth sampled in this study (1.46 m), then the adult population is estimated to be 169,400 snails, and wet biomass is estimated to be 2,084 kg (643 kg/ha). Additional research is warranted to further test the utility of mark-recapture methods for aquatic snails and to better understand Chinese mystery snail distributions within reservoirs.
Aboveground Hemiptera and Orthoptera communities were compared among three native and three resto... more Aboveground Hemiptera and Orthoptera communities were compared among three native and three restored mesic tallgrass prairies along the Platte River in central Nebraska to assess both the relative success of restored sites and the relationship between insect and plant communities. Hemiptera and Orthoptera were sampled using sweep nets in early June, mid-July, and mid-August 2000. Plant species composition was assessed in early June and mid-August. A total of 89 Auchenorrhyncha (71 Cicadellidae, 15 Fulgoroidea, and 3 Membracidae) and 23 orthopterans (15 Acrididae and 8 Tettigoniidae) were collected. Eighty-five plant species were observed in combined study sites. Shannon diversity was significantly higher at restored prairie for Cicadellidae (H9 ¼ 1.38), Fulgoroidea (H9 ¼ 0.796), and Membracidae (H9 ¼ 0.290), which comprised the majority of individual insects collected, but significantly higher at native prairie for Acrididae (H9 ¼ 0.560) and Tettigoniidae (H9 ¼ 0.480) (p • 0.05). Species richness was comparable except for Acrididae which were significantly higher in restored prairie. Density of insects generally followed species diversity but was only significantly higher in restored areas for Membracidae. The number of remnantdependent species collected was comparable for both native prairie (n ¼ 15) and restored prairie (n ¼ 15). These results suggest that, at least for Hemiptera, differences in insect communities between native and restored prairie may best be explained by the presence of insect host plants rather than by whether a site is native or restored.
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Papers by Kristine Nemec