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Data from the North American Breeding Bird Survey were used to estimate continental and regional changes in bird populations for the 2-year periods of 1993-1994 and 1994-1995. These 2-year changes were placed in the context of population trends estimated over the 1966-1995 interval. The 2-year changes were more positive during the 1993-1994 period, when 54.2% of all species exhibited positive continental trend estimates. This percentage was reduced to 47.7% during 1994-1995, as compared with 50.5% of all species having positive continental trend estimates over then entire survey period. In general, the percentage of increasing species in the Central and Western BBS regions was highest during 1993-1994, with a very...
Categories: Publication; Types: Citation; Tags: Bird Populations
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Data from the North American Breeding Bird Survey were used to estimate continental and regional changes in bird populations for the 6-yr period 2003-2008 and the 2-yr period 2007-2008. These short-term changes were placed in the context of population trends estimated over the 1966-2008 interval. Across the entire survey area, a higher proportion of species exhibited positive growth during 2003-2008 (64%) than during the long-term (46%) or the more recent 2-yr-term (39%). The 2003-2008 growth occurred relatively evenly across the Western, Central, and Eastern BBS regions, with 59%, 66%, and 61% of all species increasing, respectively. We additionally evaluated the proportion of species with positive trend estimates...
Categories: Publication; Types: Citation; Tags: Bird Populations
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The project will utilize a 4.5 million acre study area on the Montana Glaciated Plains. The objectives are to (1) identify environmental conditions and management practices that will maintain habitat for grassland birds but not impact ranching sustainability, and (2) identify areas on the landscape that have the greatest conservation potential for grassland birds. This spatial analysis will provide the framework for a rigorous assessment of management actions on the Montana Glaciated Plains.
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Rapid expansion of cropland threatens grassland ecosystems across western North America and broad-scaleplanning can be a catalyst motivating individuals and agencies to accelerate conservation. Sprague’s Pipit(Anthus spragueii) is an imperiled grassland songbird whose population has been declining rapidly in recent decades.Here, we present a strategic framework for conservation of pipits and their habitat in the northern GreatPlains.We modeled pipit distribution across its million-km2 breeding range in Canada and the U.S.We describefactors shaping distribution, delineate population cores and assess vulnerability to future grassland losses. Pipitsselected landscapes with a high proportion of continuous grassland...
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The Matador Ranch Grassbank is the most successful grassbank in the country, annually incentivizing conservation actions on over 200,000 acres of participating ranches. Incentives for management actions are in the form of discounts, which reduce the cost of leased grazing at the Matador Ranch. One of the required discounts for participating in the grassbank is a ranch management plan that guides grazing and benefits natural communities and the wildlife dependent upon them. This report details the results of our work to assess resource conditions and craft management plans with eight ranches on over 113,000 acres. Our analysis found that overall ranches implemented grazing management practices that maintained ecological...
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Temperate grasslands are among earth’s most imperiled ecosystems. In North America,steep declines of endemic songbird populations indicate that grassland loss and degradation may be approaching critical levels. Grasslands are agricultural landscapes largely (~85%) under private ownership with little formal protection status. Remaining bird populations depend on grazing lands that have not been converted to cropland. We combine regional data from a hotspot for grassland bird diversity (northeast Montana,USA; 26,500-km2) with continental data spanning the northern Great Plains (1,000,000- km2) to evaluate how land use and management influence bird distribution and abundance. Regionally, habitat used by seven grassland...
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Climate change has been implicated in the range shifts and population declines of many species, but the confounding of climate change with other variables, particularly landscape change, hampers inference about causation. Climate envelope models have been used to predict population trends and future distributions, but the reliability of such predictions remains relatively unknown; without tests of model accuracy, policy development will be based on highly uncertain ground. Our team assembled recent developments in change detection mapping and species modeling. Specifically, our objectives were to: (1) use 32-year data on bird distributions to test the reliability of climate envelope models, (2) test whether changes...
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Using data from the North American Breeding Bird Survey (BBS), continental and regional changes in bird populations were estimated for the 2-year periods of 1991-1992 and 1992-1993. These 2-year changes were placed in the context of population trends since 1966. During 1991-1992, 62% of all species exhibited positive continental trend estimates. For species showing significant population trends, 68 increased while 30 decreased. The percentage of species with positive continental trends was reduced to 45% during 1992-1993, when 39 species exhibited significant increases and 60 experienced significant decreases. Over the entire survey period of 1966-1993, 48% of all species showed positive trend estimates, with the...
Categories: Publication; Types: Citation; Tags: Bird Populations
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Data from the North American Breeding Bird Survey were used to estimate continental and regional changes in bird populations for the 5-yr period 1995-1999 and the 2-yr period 1998-1999. These short-term changes were placed in the context of population trends estimated over the 1966-1999 interval. During 1995-1999, 44% of all species exhibited positive trends over the entire survey area, while 44% of all species exhibited positive trends during 1998-1999; neither of these percentages differed significantly from 50%. The continental and regional percentages of species with positive trends were also analyzed for 12 species groups having shared life-history traits. Survey-wide for the entire survey period, grassland...
Categories: Publication; Types: Citation; Tags: Bird Populations
Abstract (from http://onlinelibrary.wiley.com/doi/10.1111/gcb.12642/abstract): Predicting biodiversity responses to climate change remains a difficult challenge, especially in climatically complex regions where precipitation is a limiting factor. Though statistical climatic envelope models are frequently used to project future scenarios for species distributions under climate change, these models are rarely tested using empirical data. We used long-term data on bird distributions and abundance covering five states in the western US and in the Canadian province of British Columbia to test the capacity of statistical models to predict temporal changes in bird populations over a 32-year period. Using boosted regression...
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We estimated statewide, regional, and national trends in counts of Bald Eagles (Haliaeetus leucocephalus) along selected routes in the contiguous United States during midwinter, 1986-2000. Each January, several hundred observers collected data as part of a survey initiated by the National Wildlife Federation in 1979. To analyze these data, we used only those routes surveyed consistently in at least four years and on which at least four eagles were counted in a single year. We included surveys conducted during fog or precipitaion after determining that changes in weather conditions probably did not affect trend estimates. Our final analysis, using a hierarchical mixed model, was based on 101,777 eagle sightings during...
Categories: Publication; Types: Citation; Tags: Bird Populations
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The North American Breeding Bird Survey (BBS) was used to estimate continental and regional changes in bird populations during 1989-1990 and 1990-1991, placing these short-term changes within the context of population trends since 1966. For the entire survey area, 51.7% of the species exhibited increases in population size during 1989-1990, reversing the decreasing tendency exhibited by the majority of species during 1988-1989. A similar percentage (51.4%) of species with increasing populations was noted during 1990-1991. These percentages were also analyzed for 12 guilds of North American birds and 3 broad geographical regions. Many regional patterns exist in these population changes, reflecting the variability...
Categories: Publication; Types: Citation; Tags: Bird Populations
The consequences of climate change for ecosystem structure and function remain largely unknown. Here, I examine the ability of climate variation to explain long-term changes in bird and plant populations, as well as trophic interactions in a high-elevation riparian system in central Arizona, USA, based on 20 years of study. Abundances of dominant deciduous trees have declined dramatically over the 20 years, correlated with a decline in overwinter snowfall. Snowfall can affect overwinter presence of elk, whose browsing can significantly impact deciduous tree abundance. Thus, climate may affect the plant community indirectly through effects on herbivores, but may also act directly by influencing water availability...
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The North American Breeding Bird Survey monitors changes in bird populations through time using annual counts at fixed survey sites. The usual method of estimating trends has been to use the logarithm of the counts in a regression analysis. It is contended that this procedure is reasonably satisfactory for more abundant species, but produces biased estimates for less abundant species. An alternative estimation procedure based on estimating equations is presented.
Categories: Publication; Types: Citation; Tags: Bird Populations
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Data from the North American Breeding Bird Survey were used to estimate continental and regional changes in bird populations for the 5-yr period 1999-2003 and the 2-yr period 2002-2003. These short-term changes were placed in the context of population trends estimated over the 1966-2003 interval. During 1999-2003, 41% of all species exhibited positive trends over the entire survey area, while 64% of all species exhibited positive change between 2002-2003. The continental and regional percentages of species with positive trends were also analyzed for 12 species groups having shared life-history traits. Survey-wide for the entire survey period, grassland birds exhibited the lowest percentage of increasing species...
Categories: Publication; Types: Citation; Tags: Bird Populations
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Temperate grassland ecosystems are imperiled globally, and habitat loss in North America has resulted in steepdeclines of endemic songbirds. Commercial livestock grazing is the primary land use in rangelands that supportremaining bird populations. Some conservationists suggest using livestock as “ecosystem engineers” to increasehabitat heterogeneity in rangelands because birds require a spectrum of sparse to dense vegetation cover.However, grazing effects remain poorly understood because local studies have not incorporated broad-scaleenvironmental constraints on herbaceous growth. We surveyed grassland birds across a region spanning26 500 km2 in northeast Montana, United States to assess how distribution and abundance...


    map background search result map search result map Disentangling the Effects of Climate and Landscape Change on Bird Population Trends in the Western U.S. and Canada Grassland Bird Conservation on Working Landscapes: Spatial analysis linking populations to habitat Assessing and Implementing Ranch Management Planning at Scale through the Matador Ranch Grassbank Cows and Plows:  Science-based Conservation for Grassland Songbirds in Agricultural Landscapes Precipitation and Soil Productivity Explain Effects of Grazing on Grassland Songbirds One step ahead of the plow: Using cropland conversion risk to guide Sprague's Pipit conservation in the northern Great Plains Grassland Bird Conservation on Working Landscapes: Spatial analysis linking populations to habitat Assessing and Implementing Ranch Management Planning at Scale through the Matador Ranch Grassbank Cows and Plows:  Science-based Conservation for Grassland Songbirds in Agricultural Landscapes Precipitation and Soil Productivity Explain Effects of Grazing on Grassland Songbirds One step ahead of the plow: Using cropland conversion risk to guide Sprague's Pipit conservation in the northern Great Plains Disentangling the Effects of Climate and Landscape Change on Bird Population Trends in the Western U.S. and Canada