Browsing by Author "Buehler, David A."

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    Bald eagle distribution, abundance, roost use and response to human activity on the northern Chesapeake Bay, Maryland
    Buehler, David A. (Virginia Tech, 1990-01-11)
    I studied bald eagle (Haliaeetus leucocephalus) distribution, abundance, roost use and response to human activity on the northern Chesapeake Bay from 1984-89. The eagle population consisted of Chesapeake breeding eagles, Chesapeake nonbreeding eagles, northern-origin eagles and southern-origin eagles; changes in overall eagle distribution and abundance reflected the net changes in these 4 groups. Breeding territories on the northern Chesapeake increased from 12 to 28 from 1984 to 1988. Breeding eagles were resident all year, always ~7 km from the nest. Chesapeake nonbreeding eagles moved throughout most of the bay, but rarely left it (~5% of the radio-tagged eagles were off the bay during any month). Northern eagles migrated into the bay in late fall (x = 21 December! n = 7! range = 61 days) and departed in early spring (x = 27 March, n = 14, range = 43 days). Southern eagles arrived on the northern bay throughout April-August (x = 6 June, n = 11, range = 94 days) and departed from June - October (x = 3 September, n = 22, range = 119 days). Northern Chesapeake eagle abundance peaked twice annually; in winter (261 eagles, December 1987), driven by the presence of northern eagles, and in summer (604 eagles, August 1988), driven by the presence of southern birds. Of 1,117 radio-tagged eagle locations, only 55 (4.90/0) occurred in human-developed habitat, which composed 27.7% of 1,442 km2 of potential eagle habitat on the northern Chesapeake Bay (P < 0.001). During 36 aerial shoreline surveys, eagles were observed on only 111 of 700 (15.9%) 250-m shoreline segments that had development within 100 m, whereas eagles were observed on 312 of 859 (36.30/0) segments when development was absent (P < 0.001). On average, eagles were observed on 1.0 segment/survey that had coincident pedestrian use within 500 m, compared to 3.6 segments/survey expected if eagles and pedestrians were distributed along the shoreline independently (n = 34 surveys, P < 0.001).
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    The Birds and the Bees: Producing Beef and Conservation Benefits on Working Grasslands
    Keyser, Patrick D.; Buehler, David A.; Fike, John H.; Finke, Deborah L.; Fuhlendorf, Samuel D.; Martin, James A.; Naumann, Harley D.; Smith, S. Ray (MDPI, 2022-08-17)
    Globally, grasslands have been heavily degraded, more so than any other biome. Grasslands of the eastern U.S. are no exception to this trend and, consequently, native biota associated with the region’s >20 million ha of agricultural grasslands are under considerable stress. For example, grassland associated breeding bird populations have declined precipitously in recent decades as have numerous species of pollinators. Although there is increasing awareness of the role grasslands can play in global carbon cycles and in providing high quality dietary proteins needed by an increasing global population, there is a lack of awareness of the alarming trends in the sustainability of the native biota of these ecosystems. Here, we present the status of this conservation challenge and offer prospective solutions through a working lands conservation approach. Such a strategy entails maintaining appropriate disturbances (i.e., grazing, fire, and their combination), improved grazing management, an increased reliance on native grasses and forbs, and improved plant diversity within pastures. Furthermore, we note some examples of opportunities to achieve these goals, offer suggestions for agricultural and conservation policy, and provide a framework for evaluating tradeoffs that are inevitably required when pursuing a multi-purpose grassland management framework.