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• 1. [Article] Butterfly and flower community composition among prairie-oak ecosystem habitats in the Willamette Valley, Oregon

  Prairie-oak ecosystems in the Willamette Valley, Oregon have experienced habitat loss and degradation; most of these ecosystems are fragmented into smaller patches. Prairie-oak butterfly species, in the ...

  Citation × Citation Citation Abstract Copy Title: Butterfly and flower community composition among prairie-oak ecosystem habitats in the Willamette Valley, Oregon Author: Powers, Breanna F. Prairie-oak ecosystems in the Willamette Valley, Oregon have experienced habitat loss and degradation; most of these ecosystems are fragmented into smaller patches. Prairie-oak butterfly species, in the Willamette Valley, have decreased dramatically due to loss or degradation of habitat. More research is needed on sustaining the populations of butterflies in prairie-oak ecosystems. The purpose of my study was to examine the role prairie-oak habitats have in structuring butterfly communities in the Willamette Valley. My objectives were to: (1) assess how butterfly community structure and species composition (density, abundance, and species richness) varies along an oak canopy cover gradient in order to understand the role of habitat type in structuring butterfly communities in prairie-oak ecosystems; (2) characterize community composition of nectar resources and environmental variables known to be important for butterfly species. I also investigated temporal and structural relationships between butterfly and flower communities. I found that butterfly abundance and density were greater (p < 0.02) in prairies than in oak savannas or oak woodlands; however, species richness did not differ among habitats (p = 0.54). Ordination of prairie-oak habitats in butterfly species space with a joint plot overlay of environmental variables revealed several strong correlations; butterfly community structure was negatively correlated with litter and oak canopy cover and positively correlated to vegetation cover. The prairie, oak savanna, and oak woodland habitat types differed in nectar species community structure, though this difference was small. Non-native species were some of the most abundant flowers species found in all stands. Butterfly communities were positively related to flower communities. I detected significant seasonal patterns among the habitat types in butterfly and flower communities. Prairies appear to be the most important habitat for native butterfly populations compared to oak savanna and oak woodlands. Flowers were most prevalent in prairies and prairies had the highest percentage of native flower species; the prevalence of non-native flower species was greatest in oak woodlands. My study may represent a short-term community transition as a result of management or it may represent a more permanent community. Further study is needed to understand the effects of different management strategies for habitat restoration and the presence of non-native flower species on butterflies in prairie-oak ecosystems in the Willamette Valley. Title: Butterfly and flower community composition among prairie-oak ecosystem habitats in the Willamette Valley, Oregon Author: Powers, Breanna F. Prairie-oak ecosystems in the Willamette Valley, Oregon have experienced habitat loss and degradation; most of these ecosystems are fragmented into smaller patches. Prairie-oak butterfly species, in the Willamette Valley, have decreased dramatically due to loss or degradation of habitat. More research is needed on sustaining the populations of butterflies in prairie-oak ecosystems. The purpose of my study was to examine the role prairie-oak habitats have in structuring butterfly communities in the Willamette Valley. My objectives were to: (1) assess how butterfly community structure and species composition (density, abundance, and species richness) varies along an oak canopy cover gradient in order to understand the role of habitat type in structuring butterfly communities in prairie-oak ecosystems; (2) characterize community composition of nectar resources and environmental variables known to be important for butterfly species. I also investigated temporal and structural relationships between butterfly and flower communities. I found that butterfly abundance and density were greater (p < 0.02) in prairies than in oak savannas or oak woodlands; however, species richness did not differ among habitats (p = 0.54). Ordination of prairie-oak habitats in butterfly species space with a joint plot overlay of environmental variables revealed several strong correlations; butterfly community structure was negatively correlated with litter and oak canopy cover and positively correlated to vegetation cover. The prairie, oak savanna, and oak woodland habitat types differed in nectar species community structure, though this difference was small. Non-native species were some of the most abundant flowers species found in all stands. Butterfly communities were positively related to flower communities. I detected significant seasonal patterns among the habitat types in butterfly and flower communities. Prairies appear to be the most important habitat for native butterfly populations compared to oak savanna and oak woodlands. Flowers were most prevalent in prairies and prairies had the highest percentage of native flower species; the prevalence of non-native flower species was greatest in oak woodlands. My study may represent a short-term community transition as a result of management or it may represent a more permanent community. Further study is needed to understand the effects of different management strategies for habitat restoration and the presence of non-native flower species on butterflies in prairie-oak ecosystems in the Willamette Valley. Close

• 2. [Article] Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley

  Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native ...

  Citation × Citation Citation Abstract Copy Title: Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley Author: Taylor, Sara M. Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native burning, Willamette Valley prairies have become highly fragmented and invaded by non-native species, leaving little room for native plant diversity. Even though wetland prairie conservation and restoration has been a priority for many government agencies there is a need for research on what restoration techniques and management are necessary for increasing native species richness and abundance in remnant and restored wet prairie sites. In this research project, two studies were conducted. In the first study, data were collected on species presence and abundance from three 100m² randomized plots within three remnant wet prairies (Green Mountain, Gotter Prairie South, Knez) and three restored wet prairies (Hutchinson, Gotter Prairie North, Lovejoy) to answer the following research question, 'Are there differences between remnant and restored prairie plant communities with respect to the diversity and abundance of native species?' Analysis of variance and multivariate ordination techniques were used to assess the ecological differences between uncultivated, minimally-managed remnant wet prairies and newly-restored, highly managed wet prairies. Data on soils collected from agricultural sites (Westbrook, Zurcher, Gotter Prairie Ag), as well as the remnant and restored wet prairies mentioned above, were also used to compare soil quality and processes with the remnant and restored wetlands. Restored wet prairie had 23% higher native species cover than remnant prairie (p-value=0.089, N=6). Remnant and restored sites did not differ in native species richness (p-value=0.949, N=6). The relatively high per cent cover of native species at restored sites, (significant at the 10% level), suggests that land managers have successfully restored agricultural properties with an abundance of native species. The lack of significant difference in native species richness between remnant and restored sites also suggests that land managers have also been able to restore native plant diversity into former agricultural properties equivalent to some of the best intact remnant prairies within the Northern Willamette Valley in a short period of time (8 years or less). However, a non-metric scaling (NMS) ordination of the species matrix separated the remnant sites from the restored sites, suggesting that community composition distinguishes restored sites from remnants. The NMS results, which include environmental data in the analysis, also suggest that there is a positive correlation of percent soil moisture and percent soil organic matter associated with the remnant prairies and a positive correlation of management practices such as yearly chemical use, mowing, and clean crops, associated with the restored prairies. The location of Gotter Prairie North restoration within the ordination, between the remnant and restored sites, suggests an intermediate plant composition and soil quality. This could be attributed to intensive weed suppression and soil organic matter build up over time (8 years) in comparison to younger restored sites (3 and 4 years). Indicator species analysis identified many species with high indicator values (IVs) in the remnant prairies; Holcus lanatus, Deschampsia cespitosa, Carex densa and Phalaris arundinacea being the highest. The use of fire as a management tool produced only one species with a high IV (Camassia quamash). In the second study, three seeding treatments (Grass first, Grass and Forb together, Forb first) were compared within a 4 hectare experimental wet prairie unit to answer the research question „Which of the three seeding treatments used leads to the highest native species abundance and species richness?‟ Results from an analysis of variance indicated significant differences between treatments in native species richness for 2009 and 2010 (p-values=0.002 & 0.004 respectively) at the 5% level and native species abundance in 2010 only (p-value=0.099) at the 10% level. The Grass and Forb and Forb first treatments were highest in native species richness for 2009 and 2010, whereas the Grass and Forb and Grass first treatments were highest in native species abundance in 2010. A NMS ordination suggests that Juncus tenuis is one of the dominant species, in all seeding treatments, after one year of growth. Title: Comparing vegetation and soils of remnant and restored prairie wetlands in the northern Willamette Valley Author: Taylor, Sara M. Native prairies of the Willamette Valley are considered among the rarest of Oregon's ecosystems (Clark and Wilson, 2001). As a result of agriculture conversion, urban development and cessation of native burning, Willamette Valley prairies have become highly fragmented and invaded by non-native species, leaving little room for native plant diversity. Even though wetland prairie conservation and restoration has been a priority for many government agencies there is a need for research on what restoration techniques and management are necessary for increasing native species richness and abundance in remnant and restored wet prairie sites. In this research project, two studies were conducted. In the first study, data were collected on species presence and abundance from three 100m² randomized plots within three remnant wet prairies (Green Mountain, Gotter Prairie South, Knez) and three restored wet prairies (Hutchinson, Gotter Prairie North, Lovejoy) to answer the following research question, 'Are there differences between remnant and restored prairie plant communities with respect to the diversity and abundance of native species?' Analysis of variance and multivariate ordination techniques were used to assess the ecological differences between uncultivated, minimally-managed remnant wet prairies and newly-restored, highly managed wet prairies. Data on soils collected from agricultural sites (Westbrook, Zurcher, Gotter Prairie Ag), as well as the remnant and restored wet prairies mentioned above, were also used to compare soil quality and processes with the remnant and restored wetlands. Restored wet prairie had 23% higher native species cover than remnant prairie (p-value=0.089, N=6). Remnant and restored sites did not differ in native species richness (p-value=0.949, N=6). The relatively high per cent cover of native species at restored sites, (significant at the 10% level), suggests that land managers have successfully restored agricultural properties with an abundance of native species. The lack of significant difference in native species richness between remnant and restored sites also suggests that land managers have also been able to restore native plant diversity into former agricultural properties equivalent to some of the best intact remnant prairies within the Northern Willamette Valley in a short period of time (8 years or less). However, a non-metric scaling (NMS) ordination of the species matrix separated the remnant sites from the restored sites, suggesting that community composition distinguishes restored sites from remnants. The NMS results, which include environmental data in the analysis, also suggest that there is a positive correlation of percent soil moisture and percent soil organic matter associated with the remnant prairies and a positive correlation of management practices such as yearly chemical use, mowing, and clean crops, associated with the restored prairies. The location of Gotter Prairie North restoration within the ordination, between the remnant and restored sites, suggests an intermediate plant composition and soil quality. This could be attributed to intensive weed suppression and soil organic matter build up over time (8 years) in comparison to younger restored sites (3 and 4 years). Indicator species analysis identified many species with high indicator values (IVs) in the remnant prairies; Holcus lanatus, Deschampsia cespitosa, Carex densa and Phalaris arundinacea being the highest. The use of fire as a management tool produced only one species with a high IV (Camassia quamash). In the second study, three seeding treatments (Grass first, Grass and Forb together, Forb first) were compared within a 4 hectare experimental wet prairie unit to answer the research question „Which of the three seeding treatments used leads to the highest native species abundance and species richness?‟ Results from an analysis of variance indicated significant differences between treatments in native species richness for 2009 and 2010 (p-values=0.002 & 0.004 respectively) at the 5% level and native species abundance in 2010 only (p-value=0.099) at the 10% level. The Grass and Forb and Forb first treatments were highest in native species richness for 2009 and 2010, whereas the Grass and Forb and Grass first treatments were highest in native species abundance in 2010. A NMS ordination suggests that Juncus tenuis is one of the dominant species, in all seeding treatments, after one year of growth. Close