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• 361. [Article] Life history variables of Dicamptodon salamanders

  It is good practice to fully understand components of an ecosystem if we hope to preserve its biodiversity. A problem is that we know very little about some organisms and nothing of others. Studies that ...

  Citation × Citation Citation Abstract Copy Title: Life history variables of Dicamptodon salamanders Author: Wagner, Lisa A. It is good practice to fully understand components of an ecosystem if we hope to preserve its biodiversity. A problem is that we know very little about some organisms and nothing of others. Studies that investigate an organism’s basic biological, ecological and physiological life history variables advance our knowledge of the species of interest and also offer insight about community structure and function. In this thesis I explore courtship behaviors, metamorphic tendencies and hematological parameters in two species of Dicamptodon salamanders (D. copei and D. tenebrosus). Ecologists examine blood to assess hematological responses to a plethora of factors including hormonal changes, parasites, reproductive status and environmental stressors. While hematologic principles are fairly conserved in vertebrates, blood tissue has evolved to match the organism with its environment and there is considerable diversity in hematological parameters across taxa. Therefore, it is necessary to collect species specific baseline data for comparison. In Chapter 2, I quantified relative white blood cells and erythrocyte dry volume measurements of both D. tenebrosus and D. copei in the wild and in captivity. No prior studies have evaluated the hematological parameters of Dicamptodon salamanders. My investigation revealed similar leukocyte ratios between species and between wild and captive D. tenebrosus, while leukocyte ratios of wild and captive D. copei were significantly different. Dicamptodon species and populations vary in metamorphic tendencies though the reasons for this variation are not known. In Chapter 3 I investigated the difference in metamorphic tendencies of D. copei and D. tenebrosus. First, I tested the hypotheses that high water inhibits and thermal stress induces metamorphosis. Neither lowered water, nor increased aquatic temperatures induced metamorphosis. Secondly, I compared thermal preferences of both species and found differences in the selection tendencies between species and between sizes of both species. Lastly, I stress responses of both species to 1.66º C, 21.11 º C and 25º C water using a hematological approach. This study revealed significant differences in hematological stress indices between the two species. In Chapter 4, I explored the courtship behaviors of D. copei and D. tenebrosus and characterized each behavior and temporal pattern, using a phyloethological approach. I then compared these courtship behaviors between species and to that of the nearest salamander family, Ambystomatidae. The courtship patterns and behaviors were similar in both species, but they did not resemble the courtship patterns or behaviors of their sister taxon, Ambystoma. Title: Life history variables of Dicamptodon salamanders Author: Wagner, Lisa A. It is good practice to fully understand components of an ecosystem if we hope to preserve its biodiversity. A problem is that we know very little about some organisms and nothing of others. Studies that investigate an organism’s basic biological, ecological and physiological life history variables advance our knowledge of the species of interest and also offer insight about community structure and function. In this thesis I explore courtship behaviors, metamorphic tendencies and hematological parameters in two species of Dicamptodon salamanders (D. copei and D. tenebrosus). Ecologists examine blood to assess hematological responses to a plethora of factors including hormonal changes, parasites, reproductive status and environmental stressors. While hematologic principles are fairly conserved in vertebrates, blood tissue has evolved to match the organism with its environment and there is considerable diversity in hematological parameters across taxa. Therefore, it is necessary to collect species specific baseline data for comparison. In Chapter 2, I quantified relative white blood cells and erythrocyte dry volume measurements of both D. tenebrosus and D. copei in the wild and in captivity. No prior studies have evaluated the hematological parameters of Dicamptodon salamanders. My investigation revealed similar leukocyte ratios between species and between wild and captive D. tenebrosus, while leukocyte ratios of wild and captive D. copei were significantly different. Dicamptodon species and populations vary in metamorphic tendencies though the reasons for this variation are not known. In Chapter 3 I investigated the difference in metamorphic tendencies of D. copei and D. tenebrosus. First, I tested the hypotheses that high water inhibits and thermal stress induces metamorphosis. Neither lowered water, nor increased aquatic temperatures induced metamorphosis. Secondly, I compared thermal preferences of both species and found differences in the selection tendencies between species and between sizes of both species. Lastly, I stress responses of both species to 1.66º C, 21.11 º C and 25º C water using a hematological approach. This study revealed significant differences in hematological stress indices between the two species. In Chapter 4, I explored the courtship behaviors of D. copei and D. tenebrosus and characterized each behavior and temporal pattern, using a phyloethological approach. I then compared these courtship behaviors between species and to that of the nearest salamander family, Ambystomatidae. The courtship patterns and behaviors were similar in both species, but they did not resemble the courtship patterns or behaviors of their sister taxon, Ambystoma. Close

• 362. [Article] Onset and Breakdown of Cnidarian-Dinoflagellate Symbiosis : A Survey of the Host Transcriptomic Response and Characterization of the Sphingosine Rheostat during Symbiont Colonization and Hyperthermal Stress

  The symbiosis between cnidarians, such as corals and sea anemones, and photosynthetic dinoflagellates belonging to the genus Symbiodinium spp. is one of the most productive in the marine environment. This ...

  Citation × Citation Citation Abstract Copy Title: Onset and Breakdown of Cnidarian-Dinoflagellate Symbiosis : A Survey of the Host Transcriptomic Response and Characterization of the Sphingosine Rheostat during Symbiont Colonization and Hyperthermal Stress Author: Kitchen, Sheila Ann The symbiosis between cnidarians, such as corals and sea anemones, and photosynthetic dinoflagellates belonging to the genus Symbiodinium spp. is one of the most productive in the marine environment. This mutualistic endosymbiosis allow reef-building corals to lay down the foundation of coral reef ecosystems, which supports a highly biodiverse community of marine organisms. The relationship between the cnidarian host and algal symbiont changes over time, from the initial contact through symbiont removal. The breakdown of the partnership can be brought on by numerous environmental stressors; most notably by elevated temperatures associated with climate change. The cellular and molecular mechanisms underlying these key events in cnidarian-dinoflagellate symbiosis are still poorly understood. Lipids play a central role in symbiosis by providing cellular structure, energy storage, signaling platforms. Specifically, the signaling lipids from the sphingosine rheostat, sphingosine and sphingosine-1-phosphate (S1P), play a pivotal role in determining cell fate. Increased sphingosine drives apoptotic activity within the cell while S1P promotes cell survival. The research presented in this dissertation addresses (1) the role of signaling sphingolipids at different stages of cnidarian-dinoflagellate symbiosis and (2) the transcriptional patterns of coral larvae undergoing onset of symbiosis while exposed to elevated seawater temperatures. In Chapter 2, the proposed cnidarian sphingosine rheostat model was functionally characterized in the sea anemone Aiptasia pallida. This study identified differential response of the sphingosine rheostat with symbiont recolonization and long-term symbiont maintenance, suggesting a role in host-symbiont interactions. In Chapter 3, a heat stress experiment revealed a biphasic sphingosine rheostat response in A. pallida where acute stress inhibits rheostat expression and activity that is recovered and shifted toward cell death with longer-term heat stress. This response was not linked to symbiont loss, but has implications for a more generalized heat stress response for long-term acclimation in cnidarians. In Chapter 4, coral Acropora digitifera larvae displayed different phenotypes and transcriptional profiles with the combined stress of elevated temperature and symbiont uptake. Larval survival, symbiont colonization and algal density were highly reduced from this treatment. These transcriptional patterns indicate immune suppression, membrane reorganization and oxidative stress. Furthermore, sphingolipid signaling differed at the onset of heat stress. Overall, the work presented here indicates that the sphingosine rheostat mediates host-symbiont interactions until symbiosis dysfunction and that the determinants of symbiosis can be altered with climate-induced stress. Title: Onset and Breakdown of Cnidarian-Dinoflagellate Symbiosis : A Survey of the Host Transcriptomic Response and Characterization of the Sphingosine Rheostat during Symbiont Colonization and Hyperthermal Stress Author: Kitchen, Sheila Ann The symbiosis between cnidarians, such as corals and sea anemones, and photosynthetic dinoflagellates belonging to the genus Symbiodinium spp. is one of the most productive in the marine environment. This mutualistic endosymbiosis allow reef-building corals to lay down the foundation of coral reef ecosystems, which supports a highly biodiverse community of marine organisms. The relationship between the cnidarian host and algal symbiont changes over time, from the initial contact through symbiont removal. The breakdown of the partnership can be brought on by numerous environmental stressors; most notably by elevated temperatures associated with climate change. The cellular and molecular mechanisms underlying these key events in cnidarian-dinoflagellate symbiosis are still poorly understood. Lipids play a central role in symbiosis by providing cellular structure, energy storage, signaling platforms. Specifically, the signaling lipids from the sphingosine rheostat, sphingosine and sphingosine-1-phosphate (S1P), play a pivotal role in determining cell fate. Increased sphingosine drives apoptotic activity within the cell while S1P promotes cell survival. The research presented in this dissertation addresses (1) the role of signaling sphingolipids at different stages of cnidarian-dinoflagellate symbiosis and (2) the transcriptional patterns of coral larvae undergoing onset of symbiosis while exposed to elevated seawater temperatures. In Chapter 2, the proposed cnidarian sphingosine rheostat model was functionally characterized in the sea anemone Aiptasia pallida. This study identified differential response of the sphingosine rheostat with symbiont recolonization and long-term symbiont maintenance, suggesting a role in host-symbiont interactions. In Chapter 3, a heat stress experiment revealed a biphasic sphingosine rheostat response in A. pallida where acute stress inhibits rheostat expression and activity that is recovered and shifted toward cell death with longer-term heat stress. This response was not linked to symbiont loss, but has implications for a more generalized heat stress response for long-term acclimation in cnidarians. In Chapter 4, coral Acropora digitifera larvae displayed different phenotypes and transcriptional profiles with the combined stress of elevated temperature and symbiont uptake. Larval survival, symbiont colonization and algal density were highly reduced from this treatment. These transcriptional patterns indicate immune suppression, membrane reorganization and oxidative stress. Furthermore, sphingolipid signaling differed at the onset of heat stress. Overall, the work presented here indicates that the sphingosine rheostat mediates host-symbiont interactions until symbiosis dysfunction and that the determinants of symbiosis can be altered with climate-induced stress. Close

• 363. [Article] The Distribution and Reproductive Success of the Western Snowy Plover along the Oregon Coast - 2016

  We monitored the distribution, abundance and productivity of the federally threatened Western SnowyPlover (Charadrius nivosus nivosus) along the Oregon coast from 5 April – 31 August 2016. From north to ...

  Citation × Citation Citation Abstract Copy Title: The Distribution and Reproductive Success of the Western Snowy Plover along the Oregon Coast - 2016 Author: Farrar, J. Daniel, Kotaich, Adam A., Gaines, Eleanor P., Krygsman, Erica, Castelein, Kathleen A., Lauten, David J. We monitored the distribution, abundance and productivity of the federally threatened Western SnowyPlover (Charadrius nivosus nivosus) along the Oregon coast from 5 April – 31 August 2016. From north to south, we surveyed and monitored plover activity at Sutton Beach, Siltcoos River estuary, the Dunes Overlook, North and South Tahkenitch Creek, Tenmile Creek, Coos Bay North Spit, Bandon Snowy Plover Management Area, New River HRA and adjacent lands, and Floras Lake. Our objectives in 2016 were to: 1) estimate the size of the adult Snowy Plover population, 2) locate plover nests, 3) determine nest success, 4) implement nest protection as appropriate (e.g. ropes, signs, exclosures), 5) develop and test a sampling technique to determine plover productivity, 6) monitor brood outcomes, and 7) collect general observational data about predators and use cameras to document predator activity at nests. We estimated the resident number of Snowy Plovers in Oregon at 518 individuals. The adult plover population was the highest estimate recorded since monitoring began in 1990. We monitored 694 nests in 2016. Overall apparent nest success was 25%. Nest failures were attributed to unknown depredation, unknown cause, harrier depredation, corvid depredation, mammalian depredation, gull depredation, one-egg nest, wind/weather, abandonment, overwashing and infertility. We monitored a sample of 150 of 192 known broods, and documented a minimum of 197 fledglings. Overall brood success was 71%, fledging success was 43%, but only 0.60 +/- 0.09 fledglings per male were produced. Title: The Distribution and Reproductive Success of the Western Snowy Plover along the Oregon Coast - 2016 Author: Farrar, J. Daniel, Kotaich, Adam A., Gaines, Eleanor P., Krygsman, Erica, Castelein, Kathleen A., Lauten, David J. We monitored the distribution, abundance and productivity of the federally threatened Western SnowyPlover (Charadrius nivosus nivosus) along the Oregon coast from 5 April – 31 August 2016. From north to south, we surveyed and monitored plover activity at Sutton Beach, Siltcoos River estuary, the Dunes Overlook, North and South Tahkenitch Creek, Tenmile Creek, Coos Bay North Spit, Bandon Snowy Plover Management Area, New River HRA and adjacent lands, and Floras Lake. Our objectives in 2016 were to: 1) estimate the size of the adult Snowy Plover population, 2) locate plover nests, 3) determine nest success, 4) implement nest protection as appropriate (e.g. ropes, signs, exclosures), 5) develop and test a sampling technique to determine plover productivity, 6) monitor brood outcomes, and 7) collect general observational data about predators and use cameras to document predator activity at nests. We estimated the resident number of Snowy Plovers in Oregon at 518 individuals. The adult plover population was the highest estimate recorded since monitoring began in 1990. We monitored 694 nests in 2016. Overall apparent nest success was 25%. Nest failures were attributed to unknown depredation, unknown cause, harrier depredation, corvid depredation, mammalian depredation, gull depredation, one-egg nest, wind/weather, abandonment, overwashing and infertility. We monitored a sample of 150 of 192 known broods, and documented a minimum of 197 fledglings. Overall brood success was 71%, fledging success was 43%, but only 0.60 +/- 0.09 fledglings per male were produced. Close

• 364. [Article] Mapping conservation opportunity areas for the Intertwine's Regional Conservation Strategy

  Draft report from the Institute for Natural Resources, Portland State University

  Citation × Citation Citation Abstract Copy Title: Mapping conservation opportunity areas for the Intertwine's Regional Conservation Strategy Author: Kagan, James S., Burcsu, Theresa Draft report from the Institute for Natural Resources, Portland State University Title: Mapping conservation opportunity areas for the Intertwine's Regional Conservation Strategy Author: Kagan, James S., Burcsu, Theresa Draft report from the Institute for Natural Resources, Portland State University Close

• 365. [Article] Vascular Plant Inventory for Lewis and Clark National Historical Park - Public Version

  Natural Resource Technical Report NPS/LEWI/NRTR—2012/603.N Research was conducted under permit # FOCL-2009-SCI-0002 for study number FOCL-00005

  Citation × Citation Citation Abstract Copy Title: Vascular Plant Inventory for Lewis and Clark National Historical Park - Public Version Author: Kagan, Jimmy, Institute for Natural Resources, Wise, Lindsey Koepke, The Oregon Biodiversity Information Center Natural Resource Technical Report NPS/LEWI/NRTR—2012/603.N Research was conducted under permit # FOCL-2009-SCI-0002 for study number FOCL-00005 Title: Vascular Plant Inventory for Lewis and Clark National Historical Park - Public Version Author: Kagan, Jimmy, Institute for Natural Resources, Wise, Lindsey Koepke, The Oregon Biodiversity Information Center Natural Resource Technical Report NPS/LEWI/NRTR—2012/603.N Research was conducted under permit # FOCL-2009-SCI-0002 for study number FOCL-00005 Close

• 366. [Article] Precipitation and winter temperature predict long-term range-scale abundance changes in Western North American birds

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by John Wiley & Sons Ltd., and can be found at: http://onlinelibrary.wiley.com/jou...

  Citation × Citation Citation Abstract Copy Title: Precipitation and winter temperature predict long-term range-scale abundance changes in Western North American birds Author: Jones, Julia A., Illán, Javier Gutiérrez, Thomas, Chris D., Shirley, Susan M., Betts, Matthew G., Wong, Weng-Keen This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by John Wiley & Sons Ltd., and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-2486 Title: Precipitation and winter temperature predict long-term range-scale abundance changes in Western North American birds Author: Jones, Julia A., Illán, Javier Gutiérrez, Thomas, Chris D., Shirley, Susan M., Betts, Matthew G., Wong, Weng-Keen This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by John Wiley & Sons Ltd., and can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291365-2486 Close

• 367. [Article] The Distribution and Reproductive Success of the Western Snowy Plover along the Oregon Coast - 2011

  From 6 April – 19 September 2011 we monitored the distribution, abundance and productivity of the federally Threatened Western Snowy Plover (Charadrius nivosus nivosus) along the Oregon coast. From north ...

  Citation × Citation Citation Abstract Copy Title: The Distribution and Reproductive Success of the Western Snowy Plover along the Oregon Coast - 2011 Author: Institute for Natural Resources, Kotaich, Adam A., Portland State University/INR, Farrar, J. Daniel, The Oregon Biodiversity Information Center, Castelein, Kathleen A, Gaines, Eleanor P., Lauten, David J. From 6 April – 19 September 2011 we monitored the distribution, abundance and productivity of the federally Threatened Western Snowy Plover (Charadrius nivosus nivosus) along the Oregon coast. From north to south, we surveyed and monitored plover activity at Sutton Beach, Siltcoos River estuary, the Dunes Overlook, North Tahkenitch Creek, Tenmile Creek, Coos Bay North Spit, Bandon Beach, New River, and Floras Lake. Our objectives for the Oregon coastal population in 2011 were to: 1) estimate the size of the adult Snowy Plover population, 2) locate plover nests, 3) continue use of mini-exclosures (MEs) to protect nests from predators when and where needed, 4) determine nest success, 5) determine fledging success, 6) monitor brood movements, 7) collect general observational data about predators, and 8) evaluate the effectiveness of predator management. We observed an estimated 247-253 adult Snowy Plovers; a minimum of 214 individuals were known to have nested. The adult plover population was the highest estimate recorded since monitoring began in 1990. We monitored 289 nests in 2011, the highest number of nests since monitoring began in 1990. Overall apparent nest success was 50%. Exclosed nests (n = 48) had a 71% apparent nest success rate, and unexclosed nests (n = 241) had a 48% apparent nest success rate. Nest failures were attributed to unknown depredation (22%), corvid depredation (20%), unknown cause (18%), one-egg nests (16%), abandonment (15%), wind/weather (3%), mammalian depredation (2%), adult plover depredation (2%), infertility (1%), and rodent depredation (1%). We monitored 148 broods, including four from unknown nests, and documented a minimum of 168 fledglings. Overall brood success was 71%, fledging success was 46%, and 1.57 fledglings per male were produced. Continued predator management, habitat improvement and maintenance, and management of recreational activities at all sites are recommended to achieve recovery goals. Title: The Distribution and Reproductive Success of the Western Snowy Plover along the Oregon Coast - 2011 Author: Institute for Natural Resources, Kotaich, Adam A., Portland State University/INR, Farrar, J. Daniel, The Oregon Biodiversity Information Center, Castelein, Kathleen A, Gaines, Eleanor P., Lauten, David J. From 6 April – 19 September 2011 we monitored the distribution, abundance and productivity of the federally Threatened Western Snowy Plover (Charadrius nivosus nivosus) along the Oregon coast. From north to south, we surveyed and monitored plover activity at Sutton Beach, Siltcoos River estuary, the Dunes Overlook, North Tahkenitch Creek, Tenmile Creek, Coos Bay North Spit, Bandon Beach, New River, and Floras Lake. Our objectives for the Oregon coastal population in 2011 were to: 1) estimate the size of the adult Snowy Plover population, 2) locate plover nests, 3) continue use of mini-exclosures (MEs) to protect nests from predators when and where needed, 4) determine nest success, 5) determine fledging success, 6) monitor brood movements, 7) collect general observational data about predators, and 8) evaluate the effectiveness of predator management. We observed an estimated 247-253 adult Snowy Plovers; a minimum of 214 individuals were known to have nested. The adult plover population was the highest estimate recorded since monitoring began in 1990. We monitored 289 nests in 2011, the highest number of nests since monitoring began in 1990. Overall apparent nest success was 50%. Exclosed nests (n = 48) had a 71% apparent nest success rate, and unexclosed nests (n = 241) had a 48% apparent nest success rate. Nest failures were attributed to unknown depredation (22%), corvid depredation (20%), unknown cause (18%), one-egg nests (16%), abandonment (15%), wind/weather (3%), mammalian depredation (2%), adult plover depredation (2%), infertility (1%), and rodent depredation (1%). We monitored 148 broods, including four from unknown nests, and documented a minimum of 168 fledglings. Overall brood success was 71%, fledging success was 46%, and 1.57 fledglings per male were produced. Continued predator management, habitat improvement and maintenance, and management of recreational activities at all sites are recommended to achieve recovery goals. Close

• 368. [Article] Western juniper encroachment into aspen communities in the Northwest Great Basin

  In the Northwest Great Basin, aspen (Populus tremuloides) communities uniquely contribute to the biodiversity of a semi-arid, sagebrush-dominated landscape. In this same region, western juniper (Juniperus ...

  Citation × Citation Citation Abstract Copy Title: Western juniper encroachment into aspen communities in the Northwest Great Basin Author: Wall, Travis G. In the Northwest Great Basin, aspen (Populus tremuloides) communities uniquely contribute to the biodiversity of a semi-arid, sagebrush-dominated landscape. In this same region, western juniper (Juniperus occidentalis) is encroaching into aspen stands. This study determined the timing, extent, and some of the effects of this expansion. Aspen stands below 2,133 m elevation were sampled in northwest Nevada, northeast California, and southeast Oregon for density, canopy cover, age, stand structure, and recruitment of western juniper and aspen. Soils and tree litter from both species were collected to analyze the effects of western juniper in areas previously influenced by aspen. Additionally, two large aspen complexes in southeast Oregon were intensively aged to determine disturbance (fire) frequencies. Western juniper encroachment into aspen stands peaked from 1920 to 1939 with 77% of all juniper trees sampled establishing during this period. Five percent were greater than 100 years and none exceeded 145 years. Three-fourths of aspen stands sampled have established populations of western juniper. Twenty-three percent have a dominant canopy of western juniper. Twelve percent of aspen stands sampled were completely replaced by western juniper. Average density of western juniper was 1,573 trees per hectare of aspen. Seventy percent of aspen stands sampled had zero recruitment of new aspen. Within the study area aspen stands averaged 98 years old. Forty-eight percent of stands were greater than 100 years old. There was an inverse correlation between aspen canopy cover and western juniper canopy cover (r²=.80, p=.0001). Soils influenced by western juniper had a higher C:N ratio and pH; higher amounts of salts, lime, and sulfate; and lower amounts of magnesium, iron, copper, and manganese (p<.05). Aspen litter had a lower C:N ratio than western juniper litter (p<.05). Prior to 1870, the two major aspen complexes sampled had mean fire return intervals of 10 and 11 years. However, the most recent disturbance in either complex was 80 to 90 years ago. This lack of disturbance (fire) coupled with aspen stand decadence and low recruitment levels leaves aspen communities in the Northwest Great Basin vulnerable to western juniper encroachment and replacement. Title: Western juniper encroachment into aspen communities in the Northwest Great Basin Author: Wall, Travis G. In the Northwest Great Basin, aspen (Populus tremuloides) communities uniquely contribute to the biodiversity of a semi-arid, sagebrush-dominated landscape. In this same region, western juniper (Juniperus occidentalis) is encroaching into aspen stands. This study determined the timing, extent, and some of the effects of this expansion. Aspen stands below 2,133 m elevation were sampled in northwest Nevada, northeast California, and southeast Oregon for density, canopy cover, age, stand structure, and recruitment of western juniper and aspen. Soils and tree litter from both species were collected to analyze the effects of western juniper in areas previously influenced by aspen. Additionally, two large aspen complexes in southeast Oregon were intensively aged to determine disturbance (fire) frequencies. Western juniper encroachment into aspen stands peaked from 1920 to 1939 with 77% of all juniper trees sampled establishing during this period. Five percent were greater than 100 years and none exceeded 145 years. Three-fourths of aspen stands sampled have established populations of western juniper. Twenty-three percent have a dominant canopy of western juniper. Twelve percent of aspen stands sampled were completely replaced by western juniper. Average density of western juniper was 1,573 trees per hectare of aspen. Seventy percent of aspen stands sampled had zero recruitment of new aspen. Within the study area aspen stands averaged 98 years old. Forty-eight percent of stands were greater than 100 years old. There was an inverse correlation between aspen canopy cover and western juniper canopy cover (r²=.80, p=.0001). Soils influenced by western juniper had a higher C:N ratio and pH; higher amounts of salts, lime, and sulfate; and lower amounts of magnesium, iron, copper, and manganese (p<.05). Aspen litter had a lower C:N ratio than western juniper litter (p<.05). Prior to 1870, the two major aspen complexes sampled had mean fire return intervals of 10 and 11 years. However, the most recent disturbance in either complex was 80 to 90 years ago. This lack of disturbance (fire) coupled with aspen stand decadence and low recruitment levels leaves aspen communities in the Northwest Great Basin vulnerable to western juniper encroachment and replacement. Close

• 369. [Article] A ranunculalean liana stem from the cretaceous of British Columbia, Canada: Atli morinii gen. et sp nov.

  This is the publisher’s final pdf. The published article is copyrighted by The University of Chicago. and can be found at: http://www.jstor.org/action/showPublisher?publisherCode=ucpress&.

  Citation × Citation Citation Abstract Copy Title: A ranunculalean liana stem from the cretaceous of British Columbia, Canada: Atli morinii gen. et sp nov. Author: Burnham, Robyn J., Smith, Selena Y., Stockey, Ruth A., Little, Stefan A., Cooper, Ranessa L. This is the publisher’s final pdf. The published article is copyrighted by The University of Chicago. and can be found at: http://www.jstor.org/action/showPublisher?publisherCode=ucpress&. Title: A ranunculalean liana stem from the cretaceous of British Columbia, Canada: Atli morinii gen. et sp nov. Author: Burnham, Robyn J., Smith, Selena Y., Stockey, Ruth A., Little, Stefan A., Cooper, Ranessa L. This is the publisher’s final pdf. The published article is copyrighted by The University of Chicago. and can be found at: http://www.jstor.org/action/showPublisher?publisherCode=ucpress&. Close

• 370. [Article] Identifying factors driving sensitivity to fragmentation in forest breeding songbirds

  Habitat loss and fragmentation are the greatest threats to biodiversity worldwide. Fragmentation impacts landscape configuration, resulting in a larger number of patches that are smaller in size and further ...

  Citation × Citation Citation Abstract Copy Title: Identifying factors driving sensitivity to fragmentation in forest breeding songbirds Author: Valente, Jonathon J. Habitat loss and fragmentation are the greatest threats to biodiversity worldwide. Fragmentation impacts landscape configuration, resulting in a larger number of patches that are smaller in size and further apart from one another. Island biogeography and metapopulation theory predict populations in these remnant patches should be smaller, have higher extinction rates, and be less likely to receive immigrants from other populations. However, empirical data frequently do not conform with these theoretical predictions, leading to assertions that this model is too simplistic to describe distributions and dynamics of fragmented populations. However, others believe that landscape configuration effects have been poorly tested and modeled to date. In this dissertation, I use breeding bird data collected in a fragmented forest landscape to explore this lack of congruence between theory and reality. I first test the hypothesis that heterogeneity in the detectability of mobile species due to temporary emigration from sample sites can produce biased estimates of metapopulation rates. Next, I test for idiosyncrasies in the effects of forest loss and fragmentation on species belonging to different ecological trait groups. Lastly, I examine whether fragmentation actually reduces the functional connectivity of landscapes for species identified as fragmentation-sensitive. Dynamic occupancy models are popular for estimating metapopulation dynamic rates (colonization and extinction) from repeated presence/absence surveys of unmarked animals. This approach assumes closure among repeated samples within primary periods, allowing estimation of dynamic rates between these periods. However, the impact of temporary emigration (reversible changes in sampling availability) on dynamic rate estimates has not been tested. In Chapter 2, I use simulated data to investigate the degree to which temporary emigration could mislead researchers interested in quantifying metapopulation rates. I then compared results from three avian point count datasets to evaluate the likelihood that temporary emigration confounds estimates of dynamics for 19 species under a popular sampling protocol. Simulated experiments indicated that when secondary periods were open to temporary emigration, presence of dynamics was identified ≥ 95.1% of the time, and dynamic rate estimates were accurate. However, dynamic rates were biased when secondary periods were closed to temporary emigration. In empirical datasets, dynamic occupancy models had greater support than closed models for all species when secondary sampling periods occurred in immediate succession (i.e., 3 samples within 10 minutes); however, my results suggest that this is because these estimates were heavily influenced by temporary emigration. When counts within a primary period were separated by 24-48 hours, I found evidence of dynamics for less than half of these species. I recommend an alternative sampling approach that allows accurate estimation of dynamic rates when temporary emigration is of no interest, and introduce a novel model for estimating both processes simultaneously in rare cases where they are both of biological interest. Concern for violating the occupancy modeling closure assumption has led to widespread recommendations that samples within primary periods be conducted extremely close in time. However, these results indicate this is not the best approach when interest is in quantifying dynamic rates. While dynamic occupancy models provide estimates of ‘colonization’ and ‘extinction,’ these values do not inherently represent dynamics unless temporary emigration has been explicitly modeled or accounted for with sampling design. Naivete to this fact can result in incorrect conclusions about biological processes. While theory predicts that fragmentation should negatively influence biodiversity, empirical support of this idea is weak in terrestrial systems. However, tests of fragmentation effects are typically confounded with landscape composition and potentially obscured by imperfect detection. In Chapter 3, I used multi-species occupancy models and a mensurative experimental design to test competing hypotheses about how forest fragmentation influences distributions of breeding forest bird species and communities. During the breeding seasons of 2011-2013, we recorded over 80,000 bird detections in 202 forest fragments using a sampling design that isolated the effects of patch size per se from the effects of forest amount (2 km), edge, local vegetation, and sample area. I modeled the effects of these covariates on distributions of individual species categorized by ecological trait groups (i.e., forest, forest interior, or forest edge). Though my results indicated little effect of patch size on total species richness, increasing patch size tended to have a positive effect on interior species, and a negative effect on edge species. The effects of total forest amount were much more variable, and actually had a negative influence on many species, particularly cavity nesters. My results do not support theoretical predictions that forest patch size should positively influence bird species richness. However, composition of bird communities does shift toward edge species from interior species with decreasing patch size. Maintaining large forest patches is thus critical for supporting forest interior species, which tend to be of greater conservation concern. Maintenance of metapopulations requires movement of dispersers among resource patches. The degree to which a landscape facilitates or impedes such movements is defined as functional connectivity. Habitat fragmentation may reduce the functional connectivity of a landscape, but empirical linkages between distribution patterns and movement ability are lacking. In Chapter 4, I use experimental translocations to test whether forest fragmentation impedes movement of two species identified as fragmentation-sensitive in Chapter 3: Wood Thrush (Hylocichla mustelina) and Ovenbirds (Seiurus aurocapilla). I also tested for behavioral changes in translocated birds and evaluated whether fragmentation effects differed between behavioral modes. Over two breeding seasons, we translocated 35 Wood Thrush and 19 Ovenbirds (1-1.2 km) across landscapes spanning a fragmentation gradient and recorded their movement paths using VHF transmitters and receivers. Eighty-seven percent of individuals returned successfully, taking as long as 72.2 hours. Movement patterns of 96% of successful birds indicated two distinct behavioral modes: exploring, characterized by short, undirected movements and course reversals; and homing, characterized by large, fast steps towards their home territories. Forest composition and configuration had no effect on homing time or path straightness for either species. However, at a finer scale, I found that both preferred to take steps that minimized their exposure to non-forested gaps. My results demonstrate that movement limitation could drive or exacerbate fragmentation sensitivity for these birds. Further, while fragmentation effects did not differ between behavioral modes, my results highlight the need to link the dichotomous behaviors of translocated animals with natural movement processes. Despite this knowledge gap, results from our study suggest that maintaining contiguous habitat or corridors may improve functional connectivity for fragmentation-sensitive birds. Title: Identifying factors driving sensitivity to fragmentation in forest breeding songbirds Author: Valente, Jonathon J. Habitat loss and fragmentation are the greatest threats to biodiversity worldwide. Fragmentation impacts landscape configuration, resulting in a larger number of patches that are smaller in size and further apart from one another. Island biogeography and metapopulation theory predict populations in these remnant patches should be smaller, have higher extinction rates, and be less likely to receive immigrants from other populations. However, empirical data frequently do not conform with these theoretical predictions, leading to assertions that this model is too simplistic to describe distributions and dynamics of fragmented populations. However, others believe that landscape configuration effects have been poorly tested and modeled to date. In this dissertation, I use breeding bird data collected in a fragmented forest landscape to explore this lack of congruence between theory and reality. I first test the hypothesis that heterogeneity in the detectability of mobile species due to temporary emigration from sample sites can produce biased estimates of metapopulation rates. Next, I test for idiosyncrasies in the effects of forest loss and fragmentation on species belonging to different ecological trait groups. Lastly, I examine whether fragmentation actually reduces the functional connectivity of landscapes for species identified as fragmentation-sensitive. Dynamic occupancy models are popular for estimating metapopulation dynamic rates (colonization and extinction) from repeated presence/absence surveys of unmarked animals. This approach assumes closure among repeated samples within primary periods, allowing estimation of dynamic rates between these periods. However, the impact of temporary emigration (reversible changes in sampling availability) on dynamic rate estimates has not been tested. In Chapter 2, I use simulated data to investigate the degree to which temporary emigration could mislead researchers interested in quantifying metapopulation rates. I then compared results from three avian point count datasets to evaluate the likelihood that temporary emigration confounds estimates of dynamics for 19 species under a popular sampling protocol. Simulated experiments indicated that when secondary periods were open to temporary emigration, presence of dynamics was identified ≥ 95.1% of the time, and dynamic rate estimates were accurate. However, dynamic rates were biased when secondary periods were closed to temporary emigration. In empirical datasets, dynamic occupancy models had greater support than closed models for all species when secondary sampling periods occurred in immediate succession (i.e., 3 samples within 10 minutes); however, my results suggest that this is because these estimates were heavily influenced by temporary emigration. When counts within a primary period were separated by 24-48 hours, I found evidence of dynamics for less than half of these species. I recommend an alternative sampling approach that allows accurate estimation of dynamic rates when temporary emigration is of no interest, and introduce a novel model for estimating both processes simultaneously in rare cases where they are both of biological interest. Concern for violating the occupancy modeling closure assumption has led to widespread recommendations that samples within primary periods be conducted extremely close in time. However, these results indicate this is not the best approach when interest is in quantifying dynamic rates. While dynamic occupancy models provide estimates of ‘colonization’ and ‘extinction,’ these values do not inherently represent dynamics unless temporary emigration has been explicitly modeled or accounted for with sampling design. Naivete to this fact can result in incorrect conclusions about biological processes. While theory predicts that fragmentation should negatively influence biodiversity, empirical support of this idea is weak in terrestrial systems. However, tests of fragmentation effects are typically confounded with landscape composition and potentially obscured by imperfect detection. In Chapter 3, I used multi-species occupancy models and a mensurative experimental design to test competing hypotheses about how forest fragmentation influences distributions of breeding forest bird species and communities. During the breeding seasons of 2011-2013, we recorded over 80,000 bird detections in 202 forest fragments using a sampling design that isolated the effects of patch size per se from the effects of forest amount (2 km), edge, local vegetation, and sample area. I modeled the effects of these covariates on distributions of individual species categorized by ecological trait groups (i.e., forest, forest interior, or forest edge). Though my results indicated little effect of patch size on total species richness, increasing patch size tended to have a positive effect on interior species, and a negative effect on edge species. The effects of total forest amount were much more variable, and actually had a negative influence on many species, particularly cavity nesters. My results do not support theoretical predictions that forest patch size should positively influence bird species richness. However, composition of bird communities does shift toward edge species from interior species with decreasing patch size. Maintaining large forest patches is thus critical for supporting forest interior species, which tend to be of greater conservation concern. Maintenance of metapopulations requires movement of dispersers among resource patches. The degree to which a landscape facilitates or impedes such movements is defined as functional connectivity. Habitat fragmentation may reduce the functional connectivity of a landscape, but empirical linkages between distribution patterns and movement ability are lacking. In Chapter 4, I use experimental translocations to test whether forest fragmentation impedes movement of two species identified as fragmentation-sensitive in Chapter 3: Wood Thrush (Hylocichla mustelina) and Ovenbirds (Seiurus aurocapilla). I also tested for behavioral changes in translocated birds and evaluated whether fragmentation effects differed between behavioral modes. Over two breeding seasons, we translocated 35 Wood Thrush and 19 Ovenbirds (1-1.2 km) across landscapes spanning a fragmentation gradient and recorded their movement paths using VHF transmitters and receivers. Eighty-seven percent of individuals returned successfully, taking as long as 72.2 hours. Movement patterns of 96% of successful birds indicated two distinct behavioral modes: exploring, characterized by short, undirected movements and course reversals; and homing, characterized by large, fast steps towards their home territories. Forest composition and configuration had no effect on homing time or path straightness for either species. However, at a finer scale, I found that both preferred to take steps that minimized their exposure to non-forested gaps. My results demonstrate that movement limitation could drive or exacerbate fragmentation sensitivity for these birds. Further, while fragmentation effects did not differ between behavioral modes, my results highlight the need to link the dichotomous behaviors of translocated animals with natural movement processes. Despite this knowledge gap, results from our study suggest that maintaining contiguous habitat or corridors may improve functional connectivity for fragmentation-sensitive birds. Close