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• 31. [Article] Disequilibrium of Fire-prone Forests Sets the Stage for a Rapid Decline in Conifer Dominance during the 21st Century

  As trees are long-lived organisms, the impacts of climate change on forest communities may not be apparent on the time scale of years to decades. While lagged responses to environmental change are common ...

  Citation × Citation Citation Abstract Copy Title: Disequilibrium of Fire-prone Forests Sets the Stage for a Rapid Decline in Conifer Dominance during the 21st Century Author: Serra-Diaz, Josep M., Maxwell, Charles, Lucash, Melissa S., Scheller, Robert M., Laflower, Danelle M., Miller, Adam D., Tepley, Alan J., Epstein, Howard E., Anderson-Teixeira, Kristina J., Thompson, Jonathan R. Year: 2017 As trees are long-lived organisms, the impacts of climate change on forest communities may not be apparent on the time scale of years to decades. While lagged responses to environmental change are common in forested systems, potential for abrupt transitions under climate change may occur in environments where alternative vegetation states are influenced by disturbances, such as fire. The Klamath mountains (northern California and southwest Oregon, USA) are currently dominated by carbon rich and hyper-diverse temperate conifer forests, but climate change could disrupt the mechanisms promoting forest stability– regeneration and fire tolerance— via shifts in the fire regime in conjunction with lower fitness of conifers under a hotter climate. Understanding how this landscape will respond to near-term climate change (before 2100) is critical for predicting potential climate change feedbacks and to developing sound forest conservation and management plans. Using a landscape simulation model, we estimate that 1/3 of the Klamath could transition from conifer forest to shrub/hardwood chaparral, triggered by an enhanced fire activity coupled with lower post-fire conifer establishment. Such shifts were more prevalent under higher climate change forcing (RCP 8.5) but were also simulated under the climate of 1950-2000, reflecting the joint influences of early warming trends and historical forest legacies. Our results demonstrate that there is a large potential for loss of conifer forest dominance—and associated carbon stocks and biodiversity-- in the Klamath before the end of the century, and that some losses would likely occur even without the influence of climate change. Thus, in the Klamath and other forested landscapes subject to similar feedback dynamics, major ecosystem shifts should be expected when climate change disrupts key stabilizing feedbacks that maintain the dominance of long-lived, slowly regenerating trees. Title: Disequilibrium of Fire-prone Forests Sets the Stage for a Rapid Decline in Conifer Dominance during the 21st Century Author: Serra-Diaz, Josep M., Maxwell, Charles, Lucash, Melissa S., Scheller, Robert M., Laflower, Danelle M., Miller, Adam D., Tepley, Alan J., Epstein, Howard E., Anderson-Teixeira, Kristina J., Thompson, Jonathan R. Year: 2017 As trees are long-lived organisms, the impacts of climate change on forest communities may not be apparent on the time scale of years to decades. While lagged responses to environmental change are common in forested systems, potential for abrupt transitions under climate change may occur in environments where alternative vegetation states are influenced by disturbances, such as fire. The Klamath mountains (northern California and southwest Oregon, USA) are currently dominated by carbon rich and hyper-diverse temperate conifer forests, but climate change could disrupt the mechanisms promoting forest stability– regeneration and fire tolerance— via shifts in the fire regime in conjunction with lower fitness of conifers under a hotter climate. Understanding how this landscape will respond to near-term climate change (before 2100) is critical for predicting potential climate change feedbacks and to developing sound forest conservation and management plans. Using a landscape simulation model, we estimate that 1/3 of the Klamath could transition from conifer forest to shrub/hardwood chaparral, triggered by an enhanced fire activity coupled with lower post-fire conifer establishment. Such shifts were more prevalent under higher climate change forcing (RCP 8.5) but were also simulated under the climate of 1950-2000, reflecting the joint influences of early warming trends and historical forest legacies. Our results demonstrate that there is a large potential for loss of conifer forest dominance—and associated carbon stocks and biodiversity-- in the Klamath before the end of the century, and that some losses would likely occur even without the influence of climate change. Thus, in the Klamath and other forested landscapes subject to similar feedback dynamics, major ecosystem shifts should be expected when climate change disrupts key stabilizing feedbacks that maintain the dominance of long-lived, slowly regenerating trees. Close

• 32. [Article] Cephalopod Biodiversity in the Vicinity of Bear Seamount, Western North Atlantic Based on Exploratory Trawling From 2000 to 2014

  Bear Seamount (BSM) is the most inshore seamount in the New England Seamount chain. It is located within the U.S. Exclusive Economic Zone and is contained within the recently established Northeast Canyons ...

  Citation × Citation Citation Abstract Copy Title: Cephalopod Biodiversity in the Vicinity of Bear Seamount, Western North Atlantic Based on Exploratory Trawling From 2000 to 2014 Author: Shea, Elizabeth K., Judkins, Heather, Staudinger, Michelle D., Dimkovikj, Valerie H. Year: 2017 Bear Seamount (BSM) is the most inshore seamount in the New England Seamount chain. It is located within the U.S. Exclusive Economic Zone and is contained within the recently established Northeast Canyons and Seamounts Marine National Monument. In 2000, the National Oceanic and Atmospheric Administration’s (NOAA) National Systematics Laboratory began an exploratory trawling program to document nekton diversity at BSM and its vicinity. Here, we summarize eight exploratory sampling cruises conducted between 2000 and 2014, and describe the cephalopod biodiversity and assemblage structure around BSM. Over the course of 174 deep–midwater and 56 bottom tows, 5088 cephalopods were identified, measured, and documented. In total, 77 species were collected at BSM; 75 species were collected from midwater tows and 28 from benthic tows. Rarefaction curves did not reach an asymptote, suggesting that additional sampling will collect more species. Seventeen species accounted for 75% of the total midwater and bottom catch, including: Illex illecebrosus (n = 605), Magnoteuthis magna (n = 568), Abraliopsis morisii (n = 518), Abralia redfieldi (n = 358), Mastigoteuthis agassizii (n = 336), Histioteuthis reversa (n = 273), Taonius pavo (n = 239), Haliphron atlanticus (n = 195), Brachioteuthis beanii (n = 160), Ornithoteuthis antillarum (n = 153), Pterygioteuthis gemmata (n = 141), Pyroteuthis margaritifera (n = 120), Vampyroteuthis infernalis (n = 101), Chiroteuthis veranyi (n = 33), Bolitaena pygmaea (n = 30), Graneledone verrucosa (n = 11), and Stauroteuthis syrtensis (n = 29). Non-metric multidimensional scaling (NMDS) of significant analysis of similarity (ANOSIM) results showed that the 2000 cruise was different from other years, meteorological winter was different from other seasons, and that day and night shallow samples were different from each other and all other depths. Based on seasonal size variation in the most abundant taxa, we propose hypotheses of year-round, winter, and spring spawning for future critical assessment. This extensive description of the offshore cephalopod assemblage may be used to assess vulnerability to future environmental changes and human activities. Title: Cephalopod Biodiversity in the Vicinity of Bear Seamount, Western North Atlantic Based on Exploratory Trawling From 2000 to 2014 Author: Shea, Elizabeth K., Judkins, Heather, Staudinger, Michelle D., Dimkovikj, Valerie H. Year: 2017 Bear Seamount (BSM) is the most inshore seamount in the New England Seamount chain. It is located within the U.S. Exclusive Economic Zone and is contained within the recently established Northeast Canyons and Seamounts Marine National Monument. In 2000, the National Oceanic and Atmospheric Administration’s (NOAA) National Systematics Laboratory began an exploratory trawling program to document nekton diversity at BSM and its vicinity. Here, we summarize eight exploratory sampling cruises conducted between 2000 and 2014, and describe the cephalopod biodiversity and assemblage structure around BSM. Over the course of 174 deep–midwater and 56 bottom tows, 5088 cephalopods were identified, measured, and documented. In total, 77 species were collected at BSM; 75 species were collected from midwater tows and 28 from benthic tows. Rarefaction curves did not reach an asymptote, suggesting that additional sampling will collect more species. Seventeen species accounted for 75% of the total midwater and bottom catch, including: Illex illecebrosus (n = 605), Magnoteuthis magna (n = 568), Abraliopsis morisii (n = 518), Abralia redfieldi (n = 358), Mastigoteuthis agassizii (n = 336), Histioteuthis reversa (n = 273), Taonius pavo (n = 239), Haliphron atlanticus (n = 195), Brachioteuthis beanii (n = 160), Ornithoteuthis antillarum (n = 153), Pterygioteuthis gemmata (n = 141), Pyroteuthis margaritifera (n = 120), Vampyroteuthis infernalis (n = 101), Chiroteuthis veranyi (n = 33), Bolitaena pygmaea (n = 30), Graneledone verrucosa (n = 11), and Stauroteuthis syrtensis (n = 29). Non-metric multidimensional scaling (NMDS) of significant analysis of similarity (ANOSIM) results showed that the 2000 cruise was different from other years, meteorological winter was different from other seasons, and that day and night shallow samples were different from each other and all other depths. Based on seasonal size variation in the most abundant taxa, we propose hypotheses of year-round, winter, and spring spawning for future critical assessment. This extensive description of the offshore cephalopod assemblage may be used to assess vulnerability to future environmental changes and human activities. Close

• 33. [Article] International Perspectives on Sustainable Agriculture in Cuba

  Since the economic crisis following the collapse of the Soviet Union, Cuba has restructured their agriculture with a greater focus on domestic production of domestically consumed produce, and a dramatic ...

  Citation × Citation Citation Abstract Copy Title: International Perspectives on Sustainable Agriculture in Cuba Author: Smith, B. Danielle Year: 2014 Since the economic crisis following the collapse of the Soviet Union, Cuba has restructured their agriculture with a greater focus on domestic production of domestically consumed produce, and a dramatic reduction of petroleum products in all aspects of food production. This overhaul has included the broad application of what is termed agroecology – agricultural practices which focus on principles of biodiversity and sustainability – and inter-farm cooperation facilitated by the National Association of Small Farmers (ANAP) and Campesino a Campesino. Academics and journalists from within and abroad have critically examined aspects of the novel reforms developed in the country in starkly contrasting terms, as either an impressive example of sustainability in farming meeting human needs, or as an inefficient, bureaucratically bloated attempt to cope with an enduring food crisis in the country. This author speculates that both perspectives have political agendas unrelated to the observable successes or failures of food production in Cuba. The challenge is in finding the common ground between these poles of argument to clarify how Cuba’s agricultural system has shown remarkable success in recovery from crisis, and in modeling sustainable agriculture; and how it is impeded from further success by circumstances such as governmental bureaucracy, social prejudice, and insufficient profit for farmers with which to motivate ingenuity. While both perspectives can provide insight into food production in Cuba, the context of the broader political debate is present in the data and arguments of both critics and proponents of sustainable agriculture in Cuba. Title: International Perspectives on Sustainable Agriculture in Cuba Author: Smith, B. Danielle Year: 2014 Since the economic crisis following the collapse of the Soviet Union, Cuba has restructured their agriculture with a greater focus on domestic production of domestically consumed produce, and a dramatic reduction of petroleum products in all aspects of food production. This overhaul has included the broad application of what is termed agroecology – agricultural practices which focus on principles of biodiversity and sustainability – and inter-farm cooperation facilitated by the National Association of Small Farmers (ANAP) and Campesino a Campesino. Academics and journalists from within and abroad have critically examined aspects of the novel reforms developed in the country in starkly contrasting terms, as either an impressive example of sustainability in farming meeting human needs, or as an inefficient, bureaucratically bloated attempt to cope with an enduring food crisis in the country. This author speculates that both perspectives have political agendas unrelated to the observable successes or failures of food production in Cuba. The challenge is in finding the common ground between these poles of argument to clarify how Cuba’s agricultural system has shown remarkable success in recovery from crisis, and in modeling sustainable agriculture; and how it is impeded from further success by circumstances such as governmental bureaucracy, social prejudice, and insufficient profit for farmers with which to motivate ingenuity. While both perspectives can provide insight into food production in Cuba, the context of the broader political debate is present in the data and arguments of both critics and proponents of sustainable agriculture in Cuba. Close

• 34. [Article] Rapid Change in Shallow Water Fish Species Composition in an Historically Stable Antarctic Environment

  McMurdo Sound, Antarctica, is home to a unique marine biota with an ecology that has evolved in this frigid environment over millions of years. The region is one of the least disturbed, and possibly the ...

  Citation × Citation Citation Abstract Copy Title: Rapid Change in Shallow Water Fish Species Composition in an Historically Stable Antarctic Environment Author: Buckley, Bradley A. Year: 2013 McMurdo Sound, Antarctica, is home to a unique marine biota with an ecology that has evolved in this frigid environment over millions of years. The region is one of the least disturbed, and possibly the last pristine, marine ecosystem on Earth. Here, the results of three seasons of fishing in the shallow nearshore waters of McMurdo Sound are reported. A shift in the composition of small fish species at one site, Inaccessible Island, has been observed in just five years. The shift in shallow water species composition occurred during a period that followed the maturation of a commercial fishery for the Antarctic toothfish, Dissostichus mawsoni Norman, a predator of smaller fish, and the presence of a large iceberg, termed B-15, at the mouth of McMurdo Sound during the early 2000s that trapped the annual sea ice in the area leading to the unusual accrual of multi-year sea ice. The data presented here provide a current record of species composition and physiological condition of small, shallow water fishes at three sites in McMurdo Sound, providing a current baseline for the assessment of future changes wrought by environmental changes and unprecedented fishery pressures in the Ross Sea. Title: Rapid Change in Shallow Water Fish Species Composition in an Historically Stable Antarctic Environment Author: Buckley, Bradley A. Year: 2013 McMurdo Sound, Antarctica, is home to a unique marine biota with an ecology that has evolved in this frigid environment over millions of years. The region is one of the least disturbed, and possibly the last pristine, marine ecosystem on Earth. Here, the results of three seasons of fishing in the shallow nearshore waters of McMurdo Sound are reported. A shift in the composition of small fish species at one site, Inaccessible Island, has been observed in just five years. The shift in shallow water species composition occurred during a period that followed the maturation of a commercial fishery for the Antarctic toothfish, Dissostichus mawsoni Norman, a predator of smaller fish, and the presence of a large iceberg, termed B-15, at the mouth of McMurdo Sound during the early 2000s that trapped the annual sea ice in the area leading to the unusual accrual of multi-year sea ice. The data presented here provide a current record of species composition and physiological condition of small, shallow water fishes at three sites in McMurdo Sound, providing a current baseline for the assessment of future changes wrought by environmental changes and unprecedented fishery pressures in the Ross Sea. Close

• 35. [Article] Rapid and Repeatable Shifts in Life-History Timing of <i>Rhagoletis pomonella</i> (Diptera: Tephritidae) Following Colonization of Novel Host Plants in the Pacific Northwestern United States

  Host shifts of phytophagous insect specialists to novel plants can result in divergent ecological adaptation, generating reproductive isolation and potentially new species. Rhagoletis pomonellafruit flies ...

  Citation × Citation Citation Abstract Copy Title: Rapid and Repeatable Shifts in Life-History Timing of <i>Rhagoletis pomonella</i> (Diptera: Tephritidae) Following Colonization of Novel Host Plants in the Pacific Northwestern United States Author: Mattsson, Monte, Hood, Glen R., Feder, Jeffery L., Ruedas, Luis A. Year: 2015 Host shifts of phytophagous insect specialists to novel plants can result in divergent ecological adaptation, generating reproductive isolation and potentially new species. Rhagoletis pomonellafruit flies in eastern North America underwent a host shift ~160 ya from native downy hawthorn (Crataegus mollis) to introduced, domesticated apple (Malus domestica). Divergent selection on diapause phenology related to the earlier fruiting time of apples versus downy hawthorns resulted in partial allochronic reproductive isolation between the fly races. Here, we test for how rapid and repeatable shifts in life-history timing are driving ecological divergence of R. pomonella in the Pacific Northwestern USA. The fly was introduced into the region via larval-infested apples 40–65 ya and now attacks native black hawthorn (Crataegus douglasii) and introduced ornamental hawthorn (Crataegus monogyna), in addition to early- and late-maturing apple varieties in the region. To investigate the life-history timing hypothesis, we used a field-based experiment to characterize the host-associated eclosion and flight activity patterns of adults, and the feeding times of larvae at a field site in Vancouver, Washington. We also assessed the degree to which differences in host-fruiting time generate allochronic isolation among apple-, black hawthorn-, and ornamental hawthorn-associated fly populations. We conclude that host-associated fly populations are temporally offset 24.4% to 92.6% in their seasonal distributions. Our results imply that R. pomonella possesses the capacity for rapid and repeatable shifts in diapause life history to match host-fruiting phenology, which can generate ecologically based reproductive isolation, and potentially biodiversity in the process. Title: Rapid and Repeatable Shifts in Life-History Timing of <i>Rhagoletis pomonella</i> (Diptera: Tephritidae) Following Colonization of Novel Host Plants in the Pacific Northwestern United States Author: Mattsson, Monte, Hood, Glen R., Feder, Jeffery L., Ruedas, Luis A. Year: 2015 Host shifts of phytophagous insect specialists to novel plants can result in divergent ecological adaptation, generating reproductive isolation and potentially new species. Rhagoletis pomonellafruit flies in eastern North America underwent a host shift ~160 ya from native downy hawthorn (Crataegus mollis) to introduced, domesticated apple (Malus domestica). Divergent selection on diapause phenology related to the earlier fruiting time of apples versus downy hawthorns resulted in partial allochronic reproductive isolation between the fly races. Here, we test for how rapid and repeatable shifts in life-history timing are driving ecological divergence of R. pomonella in the Pacific Northwestern USA. The fly was introduced into the region via larval-infested apples 40–65 ya and now attacks native black hawthorn (Crataegus douglasii) and introduced ornamental hawthorn (Crataegus monogyna), in addition to early- and late-maturing apple varieties in the region. To investigate the life-history timing hypothesis, we used a field-based experiment to characterize the host-associated eclosion and flight activity patterns of adults, and the feeding times of larvae at a field site in Vancouver, Washington. We also assessed the degree to which differences in host-fruiting time generate allochronic isolation among apple-, black hawthorn-, and ornamental hawthorn-associated fly populations. We conclude that host-associated fly populations are temporally offset 24.4% to 92.6% in their seasonal distributions. Our results imply that R. pomonella possesses the capacity for rapid and repeatable shifts in diapause life history to match host-fruiting phenology, which can generate ecologically based reproductive isolation, and potentially biodiversity in the process. Close

• 36. [Article] The Impeccable Timing of the Apple Maggot Fly, <i>Rhagoletis pomonella</i> (Dipetera: Tephritidae), and its Implications for Ecological Speciation

  Speciation is the process by which life diversifies into discrete forms, and understanding its underlying mechanisms remains a primary focus for biologists. Increasingly, empirical studies are helping ...

  Citation × Citation Citation Abstract Copy Title: The Impeccable Timing of the Apple Maggot Fly, <i>Rhagoletis pomonella</i> (Dipetera: Tephritidae), and its Implications for Ecological Speciation Author: Mattsson, Monte Arthur Year: 2015 Speciation is the process by which life diversifies into discrete forms, and understanding its underlying mechanisms remains a primary focus for biologists. Increasingly, empirical studies are helping explain the role of ecology in generating biodiversity. Adaptive radiations are often propelled by selective fitness tradeoffs experienced by individuals that invade new habitats, resulting in reproductive isolation from ancestral conspecifics and potentially cladogenesis. Host specialist insects are among the most speciose organisms known and serve as highly useful models for studying adaptive radiations. We are just beginning to understand the pace and degree with which these insects diversify. The apple maggot, Rhagoletis pomonella, is a well-studied insect whose eastern and southern populations are models for ecological speciation. Recently (40–65 ya), the fly has invaded the Pacific Northwestern United States through human-transported apples infested with larvae. There, populations of R. pomonella have rapidly colonized two novel hawthorn hosts whose fruiting times bracket apple’s (early-season native Crataegus douglasii and introduced C. monogyna, which fruits late in the season). The recent introduction might initiate host shifts, providing opportunities to examine the pace and mechanistic means with which host races (an evolutionary stage preceding speciation) become established. Here, I demonstrate that host-associated populations at a site in southwest Washington are partially allochronically isolated from one another, and life cycles temporally match with natal host fruit ripening times in sympatry. If spatially widespread, these temporal barriers could result in reproductive isolation and possibly cladogenesis. Implications of these findings reach beyond academic import, as R. pomonella is expanding not only its host range, but its geographic range is encroaching upon central Washington, the site of a multi-billion dollar per year apple-growing industry. Title: The Impeccable Timing of the Apple Maggot Fly, <i>Rhagoletis pomonella</i> (Dipetera: Tephritidae), and its Implications for Ecological Speciation Author: Mattsson, Monte Arthur Year: 2015 Speciation is the process by which life diversifies into discrete forms, and understanding its underlying mechanisms remains a primary focus for biologists. Increasingly, empirical studies are helping explain the role of ecology in generating biodiversity. Adaptive radiations are often propelled by selective fitness tradeoffs experienced by individuals that invade new habitats, resulting in reproductive isolation from ancestral conspecifics and potentially cladogenesis. Host specialist insects are among the most speciose organisms known and serve as highly useful models for studying adaptive radiations. We are just beginning to understand the pace and degree with which these insects diversify. The apple maggot, Rhagoletis pomonella, is a well-studied insect whose eastern and southern populations are models for ecological speciation. Recently (40–65 ya), the fly has invaded the Pacific Northwestern United States through human-transported apples infested with larvae. There, populations of R. pomonella have rapidly colonized two novel hawthorn hosts whose fruiting times bracket apple’s (early-season native Crataegus douglasii and introduced C. monogyna, which fruits late in the season). The recent introduction might initiate host shifts, providing opportunities to examine the pace and mechanistic means with which host races (an evolutionary stage preceding speciation) become established. Here, I demonstrate that host-associated populations at a site in southwest Washington are partially allochronically isolated from one another, and life cycles temporally match with natal host fruit ripening times in sympatry. If spatially widespread, these temporal barriers could result in reproductive isolation and possibly cladogenesis. Implications of these findings reach beyond academic import, as R. pomonella is expanding not only its host range, but its geographic range is encroaching upon central Washington, the site of a multi-billion dollar per year apple-growing industry. Close

• 37. [Article] Community level impacts associated with the invasion of English ivy (Hedera spp.) in Forest Park: a look at the impacts of ivy on community composition and soil moisture.

  Invasive species degrade ecosystems by altering natural processes and decreasing the abundance and diversity of native flora. Communities with major fluctuations in resource supply allow invasive species ...

  Citation × Citation Citation Abstract Copy Title: Community level impacts associated with the invasion of English ivy (Hedera spp.) in Forest Park: a look at the impacts of ivy on community composition and soil moisture. Author: Copp, Sara Rose Year: 2014 Invasive species degrade ecosystems by altering natural processes and decreasing the abundance and diversity of native flora. Communities with major fluctuations in resource supply allow invasive species to exploit limiting resources making the community prone to invasion. In the Pacific Northwest, urban forests characterized with limited light and seasonally limited soil moisture are being dominated by nonnative English ivy (Hedera spp). Three observational studies were conducted in the Southern end of Forest Park within the Balch Creek Subwatershed in Portland, Oregon in order to understand 1) how English ivy changes over three growing seasons, 2) how the native understory composition responds to English ivy, 3) if the dominance of English ivy reduces soil moisture to neighboring plants, 4) how English ivy and two co-occurring native herbs (Hydrophyllum tenuipes and Vancouveria hexandra) physiologically respond to seasonal changes in soil moisture. Percent cover of the understory community was collected in both 2010 and 2013 growing seasons in 54 plots in order to understand the change in cover over time. Community response and the relationship with soil moisture was analyzed using percent cover of the understory community and associated environmental variables including soil moisture collected in 128 plots during the 2013 field season. Finally, 15 plots with co-occurring Hedera spp, H. tenuipes and V. hexandra were sampled for stomatal conductance, leaf water potential, and associated environmental variables. Results show ivy cover increases on average 14% between 2010 and 2013 while native understory cover increased on average < 1%. Once ivy forms dense cover over 44% there is a reduction of native richness, diversity and herb cover while also an increase in available soil moisture and deciduous canopy cover. There were disparate impacts to different functional groups and between species. As functional group, the herbaceous community was the most impacted by ivy invasion. The shrubs and fern community had a variable response to ivy invasion. Many of the fern and shrub species least impacted by ivy also had associations with high soil moisture and deciduous canopy cover. Finally, data suggests that ivy does not take advantage of seasonally limiting soil moisture to invade the understory community. This study indicates that English ivy is both efficient at water use and may have the ability to obtain water from distant locations throughout the forest. Once established, ivy has the ability to alter the community composition. Ivy removal and habitat restoration are essential in order to maintain and enhance biodiversity in Forest Park. Title: Community level impacts associated with the invasion of English ivy (Hedera spp.) in Forest Park: a look at the impacts of ivy on community composition and soil moisture. Author: Copp, Sara Rose Year: 2014 Invasive species degrade ecosystems by altering natural processes and decreasing the abundance and diversity of native flora. Communities with major fluctuations in resource supply allow invasive species to exploit limiting resources making the community prone to invasion. In the Pacific Northwest, urban forests characterized with limited light and seasonally limited soil moisture are being dominated by nonnative English ivy (Hedera spp). Three observational studies were conducted in the Southern end of Forest Park within the Balch Creek Subwatershed in Portland, Oregon in order to understand 1) how English ivy changes over three growing seasons, 2) how the native understory composition responds to English ivy, 3) if the dominance of English ivy reduces soil moisture to neighboring plants, 4) how English ivy and two co-occurring native herbs (Hydrophyllum tenuipes and Vancouveria hexandra) physiologically respond to seasonal changes in soil moisture. Percent cover of the understory community was collected in both 2010 and 2013 growing seasons in 54 plots in order to understand the change in cover over time. Community response and the relationship with soil moisture was analyzed using percent cover of the understory community and associated environmental variables including soil moisture collected in 128 plots during the 2013 field season. Finally, 15 plots with co-occurring Hedera spp, H. tenuipes and V. hexandra were sampled for stomatal conductance, leaf water potential, and associated environmental variables. Results show ivy cover increases on average 14% between 2010 and 2013 while native understory cover increased on average < 1%. Once ivy forms dense cover over 44% there is a reduction of native richness, diversity and herb cover while also an increase in available soil moisture and deciduous canopy cover. There were disparate impacts to different functional groups and between species. As functional group, the herbaceous community was the most impacted by ivy invasion. The shrubs and fern community had a variable response to ivy invasion. Many of the fern and shrub species least impacted by ivy also had associations with high soil moisture and deciduous canopy cover. Finally, data suggests that ivy does not take advantage of seasonally limiting soil moisture to invade the understory community. This study indicates that English ivy is both efficient at water use and may have the ability to obtain water from distant locations throughout the forest. Once established, ivy has the ability to alter the community composition. Ivy removal and habitat restoration are essential in order to maintain and enhance biodiversity in Forest Park. Close

• 38. [Article] Understory Diversity and Succession on Coarse Woody Debris in a Coastal, Old-growth Forest, Oregon

  This research examines the relationship between understory plant diversity and logs in a Pacific Northwest (PNW) Sitka spruce (Picea sitchensis)-western hemlock (Tsuga heterophylla) old-growth, coastal ...

  Citation × Citation Citation Abstract Copy Title: Understory Diversity and Succession on Coarse Woody Debris in a Coastal, Old-growth Forest, Oregon Author: Mcdonald, Shannon Lee Year: 2013 This research examines the relationship between understory plant diversity and logs in a Pacific Northwest (PNW) Sitka spruce (Picea sitchensis)-western hemlock (Tsuga heterophylla) old-growth, coastal forest. These forests are renowned for their high forest productivity, frequent wind storms, and slow log decomposition rates that produce unmatched accumulations of coarse woody debris (CWD) yet few studies have examined the relationship between CWD and understory vegetation ecology. My research addressed this topic by comparing understory plant census data between paired fallen log and forest floor sites (n=20 pairs). My objectives were to: 1) determine the influence of substrate type on community composition and diversity, and 2) examine successional pathways and species assemblage patterns on CWD in various stages of decomposition. To meet these objectives I employed non-metric multidimensional scaling (NMDS) ordinations and unsupervised cluster analyses to identify and compare community assemblages on both substrates. These methods revealed similar species diversity and evenness between log and forest floor sites with compositional differences within and between substrates corresponding to habitat availability for colonization and light and moisture gradients. My results also suggest understory successional pathways related to decay class and characterized by an initial abundance of bryophytes, forbs, and seedlings followed by woody shrubs. Understory communities developing on logs also experienced increasing diversity, evenness, and divergence from forest floor communities consistent with log decomposition. These results differ from findings for boreal forests that reveal increasing similarity between substrate communities with increasing decay class. Recommendations for future research include the employment of a more robust sample size and direct measurements of environmental variables. Additional comparator studies are also needed to confirm the effects of forest type and decomposition on the relationship between CWD and forest understory communities. This study demonstrates how fine-scale wind disturbance fosters biodiversity through the creation of CWD substrate. My results and future research are essential for the development of silvicultural models designed to promote biodiversity in PNW coastal forests. Title: Understory Diversity and Succession on Coarse Woody Debris in a Coastal, Old-growth Forest, Oregon Author: Mcdonald, Shannon Lee Year: 2013 This research examines the relationship between understory plant diversity and logs in a Pacific Northwest (PNW) Sitka spruce (Picea sitchensis)-western hemlock (Tsuga heterophylla) old-growth, coastal forest. These forests are renowned for their high forest productivity, frequent wind storms, and slow log decomposition rates that produce unmatched accumulations of coarse woody debris (CWD) yet few studies have examined the relationship between CWD and understory vegetation ecology. My research addressed this topic by comparing understory plant census data between paired fallen log and forest floor sites (n=20 pairs). My objectives were to: 1) determine the influence of substrate type on community composition and diversity, and 2) examine successional pathways and species assemblage patterns on CWD in various stages of decomposition. To meet these objectives I employed non-metric multidimensional scaling (NMDS) ordinations and unsupervised cluster analyses to identify and compare community assemblages on both substrates. These methods revealed similar species diversity and evenness between log and forest floor sites with compositional differences within and between substrates corresponding to habitat availability for colonization and light and moisture gradients. My results also suggest understory successional pathways related to decay class and characterized by an initial abundance of bryophytes, forbs, and seedlings followed by woody shrubs. Understory communities developing on logs also experienced increasing diversity, evenness, and divergence from forest floor communities consistent with log decomposition. These results differ from findings for boreal forests that reveal increasing similarity between substrate communities with increasing decay class. Recommendations for future research include the employment of a more robust sample size and direct measurements of environmental variables. Additional comparator studies are also needed to confirm the effects of forest type and decomposition on the relationship between CWD and forest understory communities. This study demonstrates how fine-scale wind disturbance fosters biodiversity through the creation of CWD substrate. My results and future research are essential for the development of silvicultural models designed to promote biodiversity in PNW coastal forests. Close

• 39. [Article] Social-Ecological Dynamics of Coral Reef Resource Use and Management

  This dissertation investigates social and ecological factors that facilitate effective management of coral reefs as social-ecological systems. Meta-analytical and field-based methods were employed to examine ...

  Citation × Citation Citation Abstract Copy Title: Social-Ecological Dynamics of Coral Reef Resource Use and Management Author: Freed, Sarah J. Year: 2013 This dissertation investigates social and ecological factors that facilitate effective management of coral reefs as social-ecological systems. Meta-analytical and field-based methods were employed to examine current management challenges and identify strategies that improve management effectiveness and coral reef health. A meta-analysis was used to evaluate biological indicators of reef health in relation to the types of fishing regulations in place (no-take areas, gear restriction areas, and periodic closures) and the actor groups (community-based, co-management, state, private) involved in management efforts for coral reef fisheries throughout the world. Other than enhancement of fish biomass within no-take areas that was significantly greater than in gear restriction areas, most biological indicators benefitted similarly from management techniques of no-take areas and gear restriction areas. Community-based and co-management were the best performing management arrangements for some biological outcomes but require further case studies to verify findings. Investigation of management effects by region indicated that previously degraded reefs received fewer benefits from management implementation than did relatively healthier reefs. For field investigations, the Comoros islands in the Western Indian Ocean served as a model for tropical coral reefs with challenging socioeconomic contexts, high biodiversity, and high vulnerability to coral reef degradation. Empirical study at 21 sites was used to identify the relative effects of natural and anthropogenic threats to coral reefs of the Comoros. Most previous studies of reef health focus on primarily natural factors or a single anthropogenic threat. This study examined suites of natural factors and human activities to identify the relative importance of each on reef health. Human activities including fishing, sand extraction, and beachfront housing and development were the best predictors of reef health status. Most notably, human population and fishing predicted fish richness, abundance, and biomass with seasonal variation in the effects, while site orientation strongly predicted benthic cover. Field studies in the Comoros were also used to investigate the roles of community and state actors in co-management and compare effectiveness of comanagement across sites with varying levels of actor participation. Effective management was found to occur with community or `meta-community' (in this case, a Marine Protected Area in which the efforts of several communities were organized) participation in governance and support of state or external agents, while resilient management that overcame considerable challenges was found to occur only with strong community participation and leadership in governance. External agents were found to contribute to development of meta-community governance structure and initiation of community participation through education and capacity building. The findings from these studies reveal that coral reef management can be improved through context appropriate regulations that address detrimental human activities and through wide acceptance and participation in governance with cooperation among states, communities, and external agents. Title: Social-Ecological Dynamics of Coral Reef Resource Use and Management Author: Freed, Sarah J. Year: 2013 This dissertation investigates social and ecological factors that facilitate effective management of coral reefs as social-ecological systems. Meta-analytical and field-based methods were employed to examine current management challenges and identify strategies that improve management effectiveness and coral reef health. A meta-analysis was used to evaluate biological indicators of reef health in relation to the types of fishing regulations in place (no-take areas, gear restriction areas, and periodic closures) and the actor groups (community-based, co-management, state, private) involved in management efforts for coral reef fisheries throughout the world. Other than enhancement of fish biomass within no-take areas that was significantly greater than in gear restriction areas, most biological indicators benefitted similarly from management techniques of no-take areas and gear restriction areas. Community-based and co-management were the best performing management arrangements for some biological outcomes but require further case studies to verify findings. Investigation of management effects by region indicated that previously degraded reefs received fewer benefits from management implementation than did relatively healthier reefs. For field investigations, the Comoros islands in the Western Indian Ocean served as a model for tropical coral reefs with challenging socioeconomic contexts, high biodiversity, and high vulnerability to coral reef degradation. Empirical study at 21 sites was used to identify the relative effects of natural and anthropogenic threats to coral reefs of the Comoros. Most previous studies of reef health focus on primarily natural factors or a single anthropogenic threat. This study examined suites of natural factors and human activities to identify the relative importance of each on reef health. Human activities including fishing, sand extraction, and beachfront housing and development were the best predictors of reef health status. Most notably, human population and fishing predicted fish richness, abundance, and biomass with seasonal variation in the effects, while site orientation strongly predicted benthic cover. Field studies in the Comoros were also used to investigate the roles of community and state actors in co-management and compare effectiveness of comanagement across sites with varying levels of actor participation. Effective management was found to occur with community or `meta-community' (in this case, a Marine Protected Area in which the efforts of several communities were organized) participation in governance and support of state or external agents, while resilient management that overcame considerable challenges was found to occur only with strong community participation and leadership in governance. External agents were found to contribute to development of meta-community governance structure and initiation of community participation through education and capacity building. The findings from these studies reveal that coral reef management can be improved through context appropriate regulations that address detrimental human activities and through wide acceptance and participation in governance with cooperation among states, communities, and external agents. Close

• 40. [Article] Countering Structural Violence: Cultivating an Experience of Positive Peace

  This thesis considers some conflicts involving indigenous peoples that arise from the universal standardization of Intellectual Property Rights (IPRs) over Plant Genetic Resources (PGR). My study presents ...

  Citation × Citation Citation Abstract Copy Title: Countering Structural Violence: Cultivating an Experience of Positive Peace Author: Stiles, Carrie E. Year: 2011 This thesis considers some conflicts involving indigenous peoples that arise from the universal standardization of Intellectual Property Rights (IPRs) over Plant Genetic Resources (PGR). My study presents the research problem of how to include indigenous peoples in dialogue as a prerequisite for conflict transformation. To better understand this problem, and potential solutions, I conducted participatory action research (PAR) through an ethnographic case study of Himalayan farmers working with the grassroots network Navdanya. The study explores the research question: how do Garhwali farmers experience grassroots mobilization for biodiversity and indigenous knowledge (IK) conservation? This question is intended to generate data for conflict resolution analysis on how to engage indigenous peoples in dialogue on the subject of IPRs over PGR. I discuss five themes that emerge from the data collected including: experiences and strategies in grassroots mobilization, culture and sharing, the seed, climate change and women. My research is divided into three separate, but interrelated elements. Firstly, I discuss my methodological choices and experiences. Secondly, I present the ethnographic research, thematic data analysis and draw conclusions. Finally, I frame the literature in the context of the theory of structural violence to explain the significance of conflicts arising from IPRs over PGR in the context of the erosion of IK systems and biodiversity. Title: Countering Structural Violence: Cultivating an Experience of Positive Peace Author: Stiles, Carrie E. Year: 2011 This thesis considers some conflicts involving indigenous peoples that arise from the universal standardization of Intellectual Property Rights (IPRs) over Plant Genetic Resources (PGR). My study presents the research problem of how to include indigenous peoples in dialogue as a prerequisite for conflict transformation. To better understand this problem, and potential solutions, I conducted participatory action research (PAR) through an ethnographic case study of Himalayan farmers working with the grassroots network Navdanya. The study explores the research question: how do Garhwali farmers experience grassroots mobilization for biodiversity and indigenous knowledge (IK) conservation? This question is intended to generate data for conflict resolution analysis on how to engage indigenous peoples in dialogue on the subject of IPRs over PGR. I discuss five themes that emerge from the data collected including: experiences and strategies in grassroots mobilization, culture and sharing, the seed, climate change and women. My research is divided into three separate, but interrelated elements. Firstly, I discuss my methodological choices and experiences. Secondly, I present the ethnographic research, thematic data analysis and draw conclusions. Finally, I frame the literature in the context of the theory of structural violence to explain the significance of conflicts arising from IPRs over PGR in the context of the erosion of IK systems and biodiversity. Close