Conservation and Ecology of Birds I

Contributed Paper
ROOM: Room 115 – Brazos
SESSION NUMBER: 20
 

1:10PM Protected Areas Facilitate Species Persistence by Reducing Extinction and Improving Colonization
Michelle Peach; Jonathan Cohen; Jacqueline Frair
Billions of dollars have been invested globally in land protection as a strategy to conserve biodiversity based on the assumption that protected areas buffer species from threats, such as habitat loss and invasive species, that drive extinctions elsewhere. Although it was not designed specifically to address the threat of climate change, the existing protected area network could become increasingly important not only for reducing extinction but also for providing colonization sites as species’ ranges shift in response to changing climatic conditions. Our goal was to evaluate whether protected areas have influenced species’ patterns of persistence over 20 years of climate and land use change. Specifically, our objectives were to 1) determine whether protected areas benefited species by increasing colonization probability and decreasing extinction probability; and 2) identify characteristics of species most likely to derive those benefits. We used breeding bird atlas data for 96 species from New York and Pennsylvania at two points in time to estimate the effect of protected areas on colonization and extinction probabilities using a single visit dynamic occupancy model to account for imperfect detection. We then compared those effects among groups of species based on habitat, range boundary location, conservation status and migratory habit. Protected areas became more important for increasing colonization and lowering extinction as forest cover and regional protection became rare. Both habitat preference and range boundary location led to significant differences in the effect of protected areas on colonization and extinction, but migratory habit and conservation status did not. Our results suggest that protected areas do facilitate species persistence in the face of changing habitat and climate by reducing the risk of extinction and providing attractive colonization sites. The benefits for individual species, however, depend on landscape context and species characteristics.
1:30PM Identifying Western Yellow-Billed Cuckoo Breeding Habitat with a Dual Modeling Approach
Matthew J. Johnson; Jennifer Holmes; James R. Hatten
The western population of the yellow-billed cuckoo (Coccyzus americanus) was recently listed as threatened under the federal Endangered Species Act. Yellow-billed cuckoo conservation efforts require the identification of features and area requirements associated with high quality, riparian forest habitat at spatial scales that range from nest microhabitat to landscape, as well as lower-suitability areas that can be enhanced or restored. Spatially explicit models inform conservation efforts by increasing ecological understanding of a target species, especially at landscape scales. Previous yellow-billed cuckoo modelling efforts derived plant-community maps from aerial photography, an expensive and oftentimes inconsistent approach. Satellite models can remotely map vegetation features (e.g., vegetation density, heterogeneity in vegetation density or structure) across large areas with near perfect repeatability, but they usually cannot identify plant communities. We used aerial photos and satellite imagery, logistic regression, and a hierarchical spatial scale approach, to identify yellow-billed cuckoo breeding habitat along the Lower Colorado River and its tributaries. Aerial-photo and satellite models identified several key features associated with yellow-billed cuckoo breeding locations: (1) a 4.5 ha core area of dense cottonwood-willow vegetation, (2) a large native, heterogeneously dense forest (72 ha) around the core area, and (3) moderately rough topography. The odds of yellow-billed cuckoo occurrence decreased rapidly as the amount of tamarisk cover increased or when cottonwood-willow vegetation was limited. We achieved model accuracies of 75 – 80% in the project area the following year after updating the imagery and location data. The two model types had very similar probability maps, largely predicting the same areas as high quality habitat. While each model provided unique information, a dual-modelling approach provided a more complete picture of yellow-billed cuckoo habitat requirements and will be useful for management and conservation activities.
1:50PM Evaluation of Methods Used to Improve Grasslands as Pheasant Brood Habitat
Mandy Orth; Kent C. Jensen; Travis Runia
Management practices designed for upland game species in the past have focused on nest survival and hen winter survival due to the importance of these life history stages on population vital rates. However, chick survival is an important component of gallinaceous bird population dynamics, it is poorly understood and often tends to be overlooked. Recent population modeling studies have found that pheasant (Phasianus colchicus) populations are more sensitive to chick survival than nesting success, which is consistent with similar models for other gallinaceous birds. Ideal brood habitat not only provides open understory for easy movement and canopy cover for protection, but also provides an abundance of arthropod foods for chicks. Our research investigated the efficacy of various methods of Conservation Reserve Program (CRP) mid-contract management to improve brood rearing habitat for upland game birds, specifically ring-necked pheasants. The objectives of this study were to (1) determine and compare relative arthropod abundance among CRP grasslands subject to several management techniques for three consecutive years post-management by using sweep nets, vacuum sampling and pitfall traps, (2) determine and compare relative arthropod availability among grasslands subject to several management techniques for three consecutive years post-management using human-imprinted chicks as models, and (3) determine and compare vegetation composition and structural characteristics among grasslands subject to several management techniques for three consecutive years post-management. Treatments that promoted vegetative diversity, such as interseeding of forbs and native wildflowers, led to increased abundance and diversity of the arthropod community and mass gain during chick foraging trials.
2:10PM Wintering Avian Occupancy on West Virginia Agricultural Conservation Easement Program Wetlands
Katharine Lewis; Christopher Rota; James T. Anderson
Wetlands on private land created through the Agricultural Conservation Easement Program are an important source of wildlife habitat, however little has been done to evaluate the ability of these wetlands to support functioning ecosystems and wildlife communities. In West Virginia, there are 24 such wetland easements established through the Agricultural Conservation Easement Program. Avian species are known indicators of habitat quality and health, therefore, a comprehensive study of the diversity, abundance, and richness of winter avian use of these wetlands is a necessary component of determining the effectiveness of conservation practices. Our objectives were to study the habitat characteristics affecting occupancy, abundance and richness of wintering Anatidae waterfowl and Emberizidae sparrows on easement wetlands during the winter of 2016-2017 by conducting point counts and transects through wetlands and taking habitat and landscape scale measurements on each wetland. We compared our results from the easement program wetlands to reference wetlands throughout West Virginia to evaluate how the easement wetlands compare to wetlands not protected under the Agricultural Conservation Easement Program. Song sparrows (Melospiza melodia), swamp sparrows (Melospiza georgiana), white-throated sparrows (Zonotrichia albicollis), and dark-eyed juncos (Junco hyemalis) were the most abundant species on both reference and easement wetlands. Waterfowl were not frequently present on wetlands owing to the small size of the wetland sites and the lack of standing open water on all of the sites. These results indicate that wetlands established under the Agricultural Conservation Easement Program are functioning similarly to other West Virginia Wetlands in terms of wintering bird habitat.
2:30PM Climate Change and Long-Term Trends in Bald Eagle Winter Habitat Use
Madeleine A. Rubenstein; Roger Christophersen; Tanya Kitterman; Jason Ransom
The Skagit River in the Pacific Northwest is a key wintering site for bald eagles (Haliaeetus leucocephalus), where they feed on the carcasses of chum (Oncorhynchus keta) and coho (Oncorhynchus kisutch) salmon after spawning. The availability of salmon carcasses is affected by flood events, which wash carcasses downstream and thereby reduce resource availability for bald eagles. Climate change is expected to alter the timing and intensity of flood events in this region, along with projected shifts in eagle phenology and distribution, reduced salmon abundance, and earlier peaks in salmon runs. Collectively, climate impacts in this system could lead to reduced resources for bald eagles. However, flows along parts of the Skagit are moderated by the management activities of a hydroelectric dam, which could serve to mitigate the most severe impacts of flood events. We use several long-term datasets on eagle detections, salmon escapement, and flow levels to examine the relationship between bald eagle habitat use, salmon abundance, and flood events along the Skagit since the late 1970s. In particular, we measure phenological shifts in eagles and salmon, changes in the timing of flood events, and the collective impacts of these changes on salmon carcass availability for bald eagles. Finally, we assess the effects of dam management on flood events, the resulting impacts on salmon carcass availability, and the potential for adaptive management to mitigate flood impacts on bald eagles. This analysis contributes to an improved understanding of complex climate change impacts to bald eagles in a dynamic ecosystem, and provides fine-scale analysis to inform river management and restoration efforts.

 

Contributed Paper
Location: Albuquerque Convention Center Date: September 24, 2017 Time: 1:10 pm - 2:50 pm