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• 1. [Article] Mason’s Run brook trout (Salvelinus fontinalis): history, management challenges, and recommendations

  Graduation date: 2016

  Citation × Citation Citation Abstract Copy Title: Mason’s Run brook trout (Salvelinus fontinalis): history, management challenges, and recommendations Author: Russell, Joseph D. III Graduation date: 2016 Title: Mason’s Run brook trout (Salvelinus fontinalis): history, management challenges, and recommendations Author: Russell, Joseph D. III Graduation date: 2016 Close

• 2. [Article] Distribution of bats in Southeast Alaska and selection of day-roosts in trees by Keen’s myotis on Prince of Wales Island, Southeast Alaska

  We conducted capture and acoustic surveys for bats in six areas along a latitudinal gradient in Southeast Alaska from mid-May to September in 2005 and we continued surveys on Prince of Wales Island from ...

  Citation × Citation Citation Abstract Copy Title: Distribution of bats in Southeast Alaska and selection of day-roosts in trees by Keen’s myotis on Prince of Wales Island, Southeast Alaska Author: Boland, Julia L. We conducted capture and acoustic surveys for bats in six areas along a latitudinal gradient in Southeast Alaska from mid-May to September in 2005 and we continued surveys on Prince of Wales Island from mid-May to September in 2006. We determined the level of effort required to catch each species and documented ranges in morphology and periods of reproduction. We captured little brown myotis, Myotis lucifugus; California myotis, M. californicus; long-legged myotis, M. volans; and Keen’s myotis, M. keenii, and we acoustically detected and sighted the silver-haired bat, Lasionycteris noctivagans. Capture success varied by species, year, and type of capture site. Our surveys support prior research suggesting that the little brown myotis is the most abundant species in the region, although densities appear to be low relative to other parts of its range. California myotis and Keen’s myotis were captured as far north as Juneau. The long-legged myotis was captured on Wrangell and Prince of Wales Islands and the silver-haired bat was detected on Prince of Wales Island. Prince of Wales Island is the southernmost area we sampled and was the only area where all species were detected. Given low rates of detection, all species appear to occur in low densities in Southeast Alaska. Better understanding of population status and trends and examination of habitat ecology and response to forest management in the region is needed to prioritize conservation strategies. The Keen’s myotis is rare and has one of the most limited distributions of any bat species in North America. Understanding gender-specific roosting ecologies of bats at relevant spatial scales is necessary to effectively evaluate the impact of habitat alteration and prioritize conservation efforts for bats in temperate forests. We examined selection of day-roosts in trees by Keen’s myotis from mid-May to September, 2006 on Prince of Wales Island, Southeast Alaska. Our objectives were to 1) examine relationships between and determine relative importance of habitat characteristics on selection of day-roosts at three spatial scales and 2) determine if habitat associations for males and females differed at each scale. We tracked 13 females to 62 roosts in trees and 6 males to 24 roosts in trees. Features at each spatial scale appeared to influence selection of day-roosts by female Keen’s myotis, but associations were strongest at the tree scale and trees used as roosts were primarily large in diameter with structural defects and located in old-growth forests. Trees in plots around roosts of females had large mean diameters and these plots had a high abundance of roost-like trees. Roosts were generally located near to roads and streams and surrounded by landscapes with a high abundance of old-growth and riparian habitat. Associations were evident for male Keen’s myotis at each spatial scale, but associations at the landscape scale were strongest. Male Keen’s myotis exhibited flexibility with the types of roosts they chose, but tree roosts were primarily snags in early to intermediate decay surrounded by a high relative abundance of roost-like trees that were closer to roads and further from riparian habitat. Habitat associations differed between males and females at each spatial scale and differences are likely a reflection of higher energetic constraints associated with reproduction for females. Energetic benefits gained from optimal roosting habitat may be critical for successful reproduction by females. Females primarily roosted in old-growth habitat and we suggest that maintaining structural components characteristic of old growth will promote conservation of Keen’s myotis in Southeast Alaska. Title: Distribution of bats in Southeast Alaska and selection of day-roosts in trees by Keen’s myotis on Prince of Wales Island, Southeast Alaska Author: Boland, Julia L. We conducted capture and acoustic surveys for bats in six areas along a latitudinal gradient in Southeast Alaska from mid-May to September in 2005 and we continued surveys on Prince of Wales Island from mid-May to September in 2006. We determined the level of effort required to catch each species and documented ranges in morphology and periods of reproduction. We captured little brown myotis, Myotis lucifugus; California myotis, M. californicus; long-legged myotis, M. volans; and Keen’s myotis, M. keenii, and we acoustically detected and sighted the silver-haired bat, Lasionycteris noctivagans. Capture success varied by species, year, and type of capture site. Our surveys support prior research suggesting that the little brown myotis is the most abundant species in the region, although densities appear to be low relative to other parts of its range. California myotis and Keen’s myotis were captured as far north as Juneau. The long-legged myotis was captured on Wrangell and Prince of Wales Islands and the silver-haired bat was detected on Prince of Wales Island. Prince of Wales Island is the southernmost area we sampled and was the only area where all species were detected. Given low rates of detection, all species appear to occur in low densities in Southeast Alaska. Better understanding of population status and trends and examination of habitat ecology and response to forest management in the region is needed to prioritize conservation strategies. The Keen’s myotis is rare and has one of the most limited distributions of any bat species in North America. Understanding gender-specific roosting ecologies of bats at relevant spatial scales is necessary to effectively evaluate the impact of habitat alteration and prioritize conservation efforts for bats in temperate forests. We examined selection of day-roosts in trees by Keen’s myotis from mid-May to September, 2006 on Prince of Wales Island, Southeast Alaska. Our objectives were to 1) examine relationships between and determine relative importance of habitat characteristics on selection of day-roosts at three spatial scales and 2) determine if habitat associations for males and females differed at each scale. We tracked 13 females to 62 roosts in trees and 6 males to 24 roosts in trees. Features at each spatial scale appeared to influence selection of day-roosts by female Keen’s myotis, but associations were strongest at the tree scale and trees used as roosts were primarily large in diameter with structural defects and located in old-growth forests. Trees in plots around roosts of females had large mean diameters and these plots had a high abundance of roost-like trees. Roosts were generally located near to roads and streams and surrounded by landscapes with a high abundance of old-growth and riparian habitat. Associations were evident for male Keen’s myotis at each spatial scale, but associations at the landscape scale were strongest. Male Keen’s myotis exhibited flexibility with the types of roosts they chose, but tree roosts were primarily snags in early to intermediate decay surrounded by a high relative abundance of roost-like trees that were closer to roads and further from riparian habitat. Habitat associations differed between males and females at each spatial scale and differences are likely a reflection of higher energetic constraints associated with reproduction for females. Energetic benefits gained from optimal roosting habitat may be critical for successful reproduction by females. Females primarily roosted in old-growth habitat and we suggest that maintaining structural components characteristic of old growth will promote conservation of Keen’s myotis in Southeast Alaska. Close

• 3. [Article] Reconnecting aquatic habitats : validating historical habitat use by anadromous fishes using telemetry and stable isotope analysis above barriers

  I conducted a study to identify potential spawning habitat for anadromous salmonids above a 60-year-old hydropower dam in the headwaters of the North Umpqua River in Oregon. Like many other historical ...

  Citation × Citation Citation Abstract Copy Title: Reconnecting aquatic habitats : validating historical habitat use by anadromous fishes using telemetry and stable isotope analysis above barriers Author: Lewis, Sierra Koch I conducted a study to identify potential spawning habitat for anadromous salmonids above a 60-year-old hydropower dam in the headwaters of the North Umpqua River in Oregon. Like many other historical salmonid-bearing rivers, little documentation exists for anadromous fish presence above potential natural obstacles upstream of Soda Springs Dam. My prediction was that if migratory salmonids are allowed to move upstream of the dam using a new fish ladder they would utilize available upstream spawning habitat. I captured, radio-tagged, and transplanted wild adult summer steelhead, O. mykiss, above Soda Springs Dam and tracked daily movements for 1 year to observe habitat preferences. I also investigated evidence of historical anadromy throughout the North Umpqua River basin using stable isotope analysis of salmon-derived nitrogen (¹⁵N) in foliar samples from Douglas fir trees, P. menziesii, (>100 years old). I tested the hypothesis that I could identify undocumented, historical salmon spawning reaches above natural and anthropogenic obstacles based solely upon δ¹⁵N foliar deposition patterns. While tracking radio-tagged steelhead, I documented holding locations, the timing of spawning activities, and the outmigration of kelts. Tagged fish did not show any extensive movement in the river or tributaries above the dam. Most of the tagged adults showed incremental daily movements near the release site or downstream into the hydropower reservoir but did not travel further than 1 kilometer upstream in the main river channel. I recorded movements and localized activities that suggested some of the fish spawned and subsequently moved downstream towards the Pacific Ocean. My observations indicated that spawning behavior of tagged fish above Soda Springs Dam was delayed several weeks relative to fish spawning below the dam. There was no evidence from telemetry that any fish moved upstream in Fish Creek, the newly accessible habitat of interest in this project. My data suggest that steelhead will use restored habitat above dams, but that re-colonization activities are variable and may be affected by altered flow regimes within the restored habitat upstream of the dam and intra-specific density dependence. My stable isotope data indicated that the foliar δ¹⁵N deposition patterns were confounded with elevation. I documented potential "salmon-derived" false positives on the Umpqua National Forest above impassable waterfalls. Overall I found that foliar δ¹⁵N deposition patterns were highly variable and unexpectedly indicated a statistically significant negative correlation of foliar δ¹⁵N values with historical salmon presence. My linear mixed-effects modeling suggests that the presence of salmon is the most important indicator of foliar δ¹⁵N values, rather than the proximity of a sampled tree to stream flow above or below migratory barriers. I was not able to use the mixed effects model to identify previously undocumented salmon spawning habitat. My results from the foliar technique suggest that the method may not be universally applicable as has been previously suggested in the literature. Title: Reconnecting aquatic habitats : validating historical habitat use by anadromous fishes using telemetry and stable isotope analysis above barriers Author: Lewis, Sierra Koch I conducted a study to identify potential spawning habitat for anadromous salmonids above a 60-year-old hydropower dam in the headwaters of the North Umpqua River in Oregon. Like many other historical salmonid-bearing rivers, little documentation exists for anadromous fish presence above potential natural obstacles upstream of Soda Springs Dam. My prediction was that if migratory salmonids are allowed to move upstream of the dam using a new fish ladder they would utilize available upstream spawning habitat. I captured, radio-tagged, and transplanted wild adult summer steelhead, O. mykiss, above Soda Springs Dam and tracked daily movements for 1 year to observe habitat preferences. I also investigated evidence of historical anadromy throughout the North Umpqua River basin using stable isotope analysis of salmon-derived nitrogen (¹⁵N) in foliar samples from Douglas fir trees, P. menziesii, (>100 years old). I tested the hypothesis that I could identify undocumented, historical salmon spawning reaches above natural and anthropogenic obstacles based solely upon δ¹⁵N foliar deposition patterns. While tracking radio-tagged steelhead, I documented holding locations, the timing of spawning activities, and the outmigration of kelts. Tagged fish did not show any extensive movement in the river or tributaries above the dam. Most of the tagged adults showed incremental daily movements near the release site or downstream into the hydropower reservoir but did not travel further than 1 kilometer upstream in the main river channel. I recorded movements and localized activities that suggested some of the fish spawned and subsequently moved downstream towards the Pacific Ocean. My observations indicated that spawning behavior of tagged fish above Soda Springs Dam was delayed several weeks relative to fish spawning below the dam. There was no evidence from telemetry that any fish moved upstream in Fish Creek, the newly accessible habitat of interest in this project. My data suggest that steelhead will use restored habitat above dams, but that re-colonization activities are variable and may be affected by altered flow regimes within the restored habitat upstream of the dam and intra-specific density dependence. My stable isotope data indicated that the foliar δ¹⁵N deposition patterns were confounded with elevation. I documented potential "salmon-derived" false positives on the Umpqua National Forest above impassable waterfalls. Overall I found that foliar δ¹⁵N deposition patterns were highly variable and unexpectedly indicated a statistically significant negative correlation of foliar δ¹⁵N values with historical salmon presence. My linear mixed-effects modeling suggests that the presence of salmon is the most important indicator of foliar δ¹⁵N values, rather than the proximity of a sampled tree to stream flow above or below migratory barriers. I was not able to use the mixed effects model to identify previously undocumented salmon spawning habitat. My results from the foliar technique suggest that the method may not be universally applicable as has been previously suggested in the literature. Close

• 4. [Article] Pacific lamprey Entosphenus tridentatus : integrating traditional ecological knowledge and contemporary values into conservation planning, and stream substrate associations with larval abundance in the Willamette River Basin, Oregon, U.S.A.

  Pacific lamprey Entosphenus tridentatus is a valuable icon and traditional food source for Indigenous people of western North America. Native Americans have utilized traditional ecological knowledge (TEK) ...

  Citation × Citation Citation Abstract Copy Title: Pacific lamprey Entosphenus tridentatus : integrating traditional ecological knowledge and contemporary values into conservation planning, and stream substrate associations with larval abundance in the Willamette River Basin, Oregon, U.S.A. Author: Sheoships, Gabe Pacific lamprey Entosphenus tridentatus is a valuable icon and traditional food source for Indigenous people of western North America. Native Americans have utilized traditional ecological knowledge (TEK) since time immemorial to guide their ways of life, transmitting cultural values and natural history to further generational knowledge. Pacific lamprey are in decline throughout their range, and have historically been disregarded in western science. The Willamette River Basin, Oregon, U.S.A currently supports a traditional harvest location, Willamette Falls, which continues to persist, despite great losses in adjacent basins and remains a harvest stronghold amongst Columbia River Basin Tribes. To further understand Pacific lamprey, we utilized both Indigenous knowledge and western science to gain information that would aid recovery. My first goal was to determine traditional ecological knowledge and the cultural values of Pacific lamprey to provide guidance for future conservation planning. My second goal was to evaluate the fine scale habitat characteristics of larval Pacific lamprey. To determine tribal values for the purpose of informing conservation planning of Pacific lamprey, I used: 1) oral history interviews of tribal elders, and 2) questionnaires distributed across entire adult (18 years and older) tribal populations. We conducted semi-structured interviews with tribal elders to gain insights into the biology, distribution, and cultural value of lamprey. I interviewed 32 tribal elders, 11 from the Grand Ronde, 10 from the Siletz, and 11 from the Umatilla. To understand modern fishing practices and current values of lamprey, I distributed a standardized questionnaire (n = 753) to a sample of each adult (18 years and older) tribal population, and received a total of 188 responses total: 38 from the Grand Ronde, 60 from the Siletz, and 90 from the Umatilla. From my interviews, I found that each tribe has noticed a decline in Pacific lamprey populations within their ceded areas, and has witnessed traditional harvest locations lost due to population declines and/or anthropogenic damage, leaving Willamette Falls as the sole harvest site for the three tribes. Questionnaire results showed that the strongest issues relating to the traditional usage of Pacific lamprey amongst each tribe are cultural awareness, harvest accessibility, and Pacific lamprey populations. I evaluated two fine scale habitat associations of larval Pacific lamprey in the Willamette River Basin to understand the association of stream sediment and larval abundance. Study objectives were to: 1) evaluate the substrate size most closely associated with larval abundance, and 2) to evaluate the influence of organic material upon larval abundance. We used a backpack electrofisher to enumerate larval lamprey in six wadeable Willamette River tributaries, using a nested two-pass sample design at a lower, middle, and upper reach (each reach composed of ten 1-m² quadrats). Stream sediment cores were collected for subsequent determination of particle size and organic composition content. I used particle size sieve analysis to estimate dominant substrate size class per sample, from the following size classes: silt (< 0.063 mm), very fine sand (0.063–0.125 mm), fine sand (0.125-0.25 mm), medium fine sand (0.25-0.50 mm), coarse sand (0.50-1.0 mm), very coarse sand (1.0-2.36 mm), and fine gravel (>2.36 mm). I analyzed organic content by loss of weight through combustion. Larvae were present in 17 of 18 reaches (94%) 18), but only detected in 37% of the quadrats. Larval Pacific lamprey abundance was highest in habitats with predominantly medium fine sand (0.25-0.50 mm) substrate. I fit negative binomial mixed models using parameters for sediment depth, percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. My top model consisted of percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. At the fine scale, substrate characteristics were associated with the abundance of larval Pacific lamprey. Appropriate conservation measures should be taken to address the restoration of Pacific lamprey, activities that promote natural river flow and distribution of sediment could be of benefit. Efforts that educate mainstream society should be implemented to reduce further species decline. With the continued decline of Pacific lamprey, there is potential for further degradation of tribal cultural values. Conservation work that promotes the restoration of Pacific lamprey is crucial to the tradition and culture of the Grand Ronde, Siletz, and Umatilla Tribes. Title: Pacific lamprey Entosphenus tridentatus : integrating traditional ecological knowledge and contemporary values into conservation planning, and stream substrate associations with larval abundance in the Willamette River Basin, Oregon, U.S.A. Author: Sheoships, Gabe Pacific lamprey Entosphenus tridentatus is a valuable icon and traditional food source for Indigenous people of western North America. Native Americans have utilized traditional ecological knowledge (TEK) since time immemorial to guide their ways of life, transmitting cultural values and natural history to further generational knowledge. Pacific lamprey are in decline throughout their range, and have historically been disregarded in western science. The Willamette River Basin, Oregon, U.S.A currently supports a traditional harvest location, Willamette Falls, which continues to persist, despite great losses in adjacent basins and remains a harvest stronghold amongst Columbia River Basin Tribes. To further understand Pacific lamprey, we utilized both Indigenous knowledge and western science to gain information that would aid recovery. My first goal was to determine traditional ecological knowledge and the cultural values of Pacific lamprey to provide guidance for future conservation planning. My second goal was to evaluate the fine scale habitat characteristics of larval Pacific lamprey. To determine tribal values for the purpose of informing conservation planning of Pacific lamprey, I used: 1) oral history interviews of tribal elders, and 2) questionnaires distributed across entire adult (18 years and older) tribal populations. We conducted semi-structured interviews with tribal elders to gain insights into the biology, distribution, and cultural value of lamprey. I interviewed 32 tribal elders, 11 from the Grand Ronde, 10 from the Siletz, and 11 from the Umatilla. To understand modern fishing practices and current values of lamprey, I distributed a standardized questionnaire (n = 753) to a sample of each adult (18 years and older) tribal population, and received a total of 188 responses total: 38 from the Grand Ronde, 60 from the Siletz, and 90 from the Umatilla. From my interviews, I found that each tribe has noticed a decline in Pacific lamprey populations within their ceded areas, and has witnessed traditional harvest locations lost due to population declines and/or anthropogenic damage, leaving Willamette Falls as the sole harvest site for the three tribes. Questionnaire results showed that the strongest issues relating to the traditional usage of Pacific lamprey amongst each tribe are cultural awareness, harvest accessibility, and Pacific lamprey populations. I evaluated two fine scale habitat associations of larval Pacific lamprey in the Willamette River Basin to understand the association of stream sediment and larval abundance. Study objectives were to: 1) evaluate the substrate size most closely associated with larval abundance, and 2) to evaluate the influence of organic material upon larval abundance. We used a backpack electrofisher to enumerate larval lamprey in six wadeable Willamette River tributaries, using a nested two-pass sample design at a lower, middle, and upper reach (each reach composed of ten 1-m² quadrats). Stream sediment cores were collected for subsequent determination of particle size and organic composition content. I used particle size sieve analysis to estimate dominant substrate size class per sample, from the following size classes: silt (< 0.063 mm), very fine sand (0.063–0.125 mm), fine sand (0.125-0.25 mm), medium fine sand (0.25-0.50 mm), coarse sand (0.50-1.0 mm), very coarse sand (1.0-2.36 mm), and fine gravel (>2.36 mm). I analyzed organic content by loss of weight through combustion. Larvae were present in 17 of 18 reaches (94%) 18), but only detected in 37% of the quadrats. Larval Pacific lamprey abundance was highest in habitats with predominantly medium fine sand (0.25-0.50 mm) substrate. I fit negative binomial mixed models using parameters for sediment depth, percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. My top model consisted of percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. At the fine scale, substrate characteristics were associated with the abundance of larval Pacific lamprey. Appropriate conservation measures should be taken to address the restoration of Pacific lamprey, activities that promote natural river flow and distribution of sediment could be of benefit. Efforts that educate mainstream society should be implemented to reduce further species decline. With the continued decline of Pacific lamprey, there is potential for further degradation of tribal cultural values. Conservation work that promotes the restoration of Pacific lamprey is crucial to the tradition and culture of the Grand Ronde, Siletz, and Umatilla Tribes. Close

• 5. [Article] Twenty-year changes in riparian bird communities of east-central Oregon

  Over the last 50 years, riparian zones in the semi-arid West have gained recognition as disproportionately important habitats for both breeding bird communities and agricultural operations. Despite growing ...

  Citation × Citation Citation Abstract Copy Title: Twenty-year changes in riparian bird communities of east-central Oregon Author: Ellis, Michael S. Over the last 50 years, riparian zones in the semi-arid West have gained recognition as disproportionately important habitats for both breeding bird communities and agricultural operations. Despite growing interest in exploring avian-habitat relationships in these systems to better inform land management, few studies have attempted to describe temporal changes in the region's riparian bird communities. To provide a frame of reference for these changes, we compared indices of avian abundance and diversity from three streamside vegetation associations in east-central Oregon during the 2014 breeding season with baseline data collected by TA Sanders and WD Edge in 1993 and 1994 (Sanders and Edge 1998). Our objectives were to identify patterns of change in the avian community with a focus on riparian shrub-dependent species, to re-examine previously reported relationships between avian abundance and vegetation volume, and to identify possible causes of declines in abundance and diversity with the goal of providing land managers in the semi-arid region information to be used in the guidance and adaptation of management practices. We combined field protocols used by Sanders and Edge to survey birds along point count transects and to measure riparian vegetation with modern analytical techniques. We found few major differences in overall diversity between study periods, but documented precipitous declines in detections for two of three riparian shrub-dependent focal species - Yellow Warbler (Setophaga petechia) and Willow Flycatcher (Empidonax trailii). Song Sparrow (Melospiza melodia) detections declined by a smaller margin. Changes in number of detections for these species did not reflect trends in mesic shrub volume, which had been identified as a likely driver of obligate species abundance by Sanders and Edge but remained relatively unchanged between study periods. Declines of all three focal species reflected regional Breeding Bird Survey trends, corroborating our finding that their declines may not be a result of changes in local site conditions. Compositional similarity between avian communities was significantly higher in 2014 than in 1993-1994, exhibiting a shift toward greater homogenization between structurally distinct riparian habitats. Our results suggest managing working lands for riparian shrub cover or volume, an important metric of grazing intensity and riparian system health, may not be enough to conserve diversity and abundance of riparian-shrub dependent birds, and more work should be done to identify and alleviate factors contributing to these species' declines. Title: Twenty-year changes in riparian bird communities of east-central Oregon Author: Ellis, Michael S. Over the last 50 years, riparian zones in the semi-arid West have gained recognition as disproportionately important habitats for both breeding bird communities and agricultural operations. Despite growing interest in exploring avian-habitat relationships in these systems to better inform land management, few studies have attempted to describe temporal changes in the region's riparian bird communities. To provide a frame of reference for these changes, we compared indices of avian abundance and diversity from three streamside vegetation associations in east-central Oregon during the 2014 breeding season with baseline data collected by TA Sanders and WD Edge in 1993 and 1994 (Sanders and Edge 1998). Our objectives were to identify patterns of change in the avian community with a focus on riparian shrub-dependent species, to re-examine previously reported relationships between avian abundance and vegetation volume, and to identify possible causes of declines in abundance and diversity with the goal of providing land managers in the semi-arid region information to be used in the guidance and adaptation of management practices. We combined field protocols used by Sanders and Edge to survey birds along point count transects and to measure riparian vegetation with modern analytical techniques. We found few major differences in overall diversity between study periods, but documented precipitous declines in detections for two of three riparian shrub-dependent focal species - Yellow Warbler (Setophaga petechia) and Willow Flycatcher (Empidonax trailii). Song Sparrow (Melospiza melodia) detections declined by a smaller margin. Changes in number of detections for these species did not reflect trends in mesic shrub volume, which had been identified as a likely driver of obligate species abundance by Sanders and Edge but remained relatively unchanged between study periods. Declines of all three focal species reflected regional Breeding Bird Survey trends, corroborating our finding that their declines may not be a result of changes in local site conditions. Compositional similarity between avian communities was significantly higher in 2014 than in 1993-1994, exhibiting a shift toward greater homogenization between structurally distinct riparian habitats. Our results suggest managing working lands for riparian shrub cover or volume, an important metric of grazing intensity and riparian system health, may not be enough to conserve diversity and abundance of riparian-shrub dependent birds, and more work should be done to identify and alleviate factors contributing to these species' declines. Close