Biology subjects

Michel, N. L.

Publications and source records attributed to Michel, N. L..

7 recordsLinked to original sources

bioRxiv2026

Operationalizing site-level conservation for migratory birds across the Americas flyways

Conserving migratory birds effectively requires full annual cycle strategies that identify where on-the-ground efforts can have the greatest impact. Here, we present a hemispheric spatial framework to identify priority areas for 112 migratory bird species across the Americas. Building on full annual cycle prioritizations, we defined finer-scale spatial planning units that reflect differences in migratory and congregational behaviors between shorebirds and landbirds. We compiled population data for each planning unit and focal species and applied conservation planning tools to design area-efficient portfolios of sites and landscapes that secure 10% of each species population within the Americas flyways. The resulting minimum area portfolios include 175 shorebird sites and 80 landbird landscapes optimized to meet the species-specific 10% representation targets across breeding, non-breeding, and passage seasons. We also identified a broader set of complementary solutions, ranked by an importance score, to provide decision-makers with flexible options for strategic resource allocation. This framework provides the scientific foundation for the Americas Flyways Initiative (AFI), which aims to catalyze investment in nature-based solutions and bird-friendly infrastructure to enhance the conservation of migratory birds and strengthen the resilience of the Americas flyways by 2050.

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bioRxiv2023

Assessment of Landbird Population Change in the Southeastern United States

Birds and their habitats are facing unprecedented threats from a multitude of threats. Threats to birds, and consequently their population trajectories, vary both across space and among species groups, and greater knowledge of these patterns will help inform bird conservation and management. Here, we adapt existing methods to estimate continental bird population loss to a regional scale. Our objectives were to (1) identify patterns in regional population change (abundance) for 141 species of landbirds breeding in the Southeast; (2) compare these with continental patterns for the same suites of species, and (3) examine whether population-level changes in the Southeast suggest immediate, regional conservation actions. We found that landbird population losses were overall similar in the Southeast and across North America (-21%). Shrikes, nightjars, and swifts experienced the largest proportional losses among families in both regions. Birds associated with early seral and emergent wetland habitats experienced the greatest losses as did partial migrants and species listed on the Birds of Conservation Concern list for southeastern Bird Conservation Regions. Facultative aerial insectivores experienced the greatest losses in both regions, while obligate aerial insectivores increased in the Southeast in contrast to continental declines, due to rapid population growth in Cliff Swallows (Petrochelidon pyrrhonota). Within the Southeast, the greatest bird losses were in Peninsular Florida and Gulf Coastal Prairie, while the Mississippi Alluvial Valley Bird Conservation Region - where extensive reforestation efforts have been undertaken - had the smallest losses. We found clear differences in patterns of landbird population loss between the Southeastern United States and North America, as well as within the Southeast region. Results from these analyses should provide conservation agencies and partnerships with additional information and new perspectives to guide landscape-level planning and on-the-ground bird conservation delivery efforts to help bring back the nearly three billion birds lost across North America since 1970. DisclaimerThe findings and conclusions in this article are those of the authors and do not necessarily represent the views of the U.S. Fish and Wildlife Service.

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bioRxiv2023

A framework for linking hemispheric, full annual cycle prioritizations to local conservation actions for migratory birds

The conservation of migratory birds poses a fundamental challenge: their conservation requires coordinated action across the hemisphere, but those actions must be designed and implemented locally. To address this challenge, we describe a multi-level framework for linking broad-scale, full annual cycle prioritizations to local conservation actions for migratory birds. We developed hemisphere-scale spatial prioritizations for the full annual cycle of migratory birds that breed in six different ecosystems in North America. The full annual cycle prioritizations provide a hemispheric context within which regional priorities can be identifieed. Finer resolution, regional prioritizations can then inform local conservation actions more effectively. We describe the importance of local conservation practitioner contributions at each level of the process and provide two examples of regional spatial prioritizations that were developed to guide local action. The fierst example focused on coastal North and South Carolina, USA, and used information on marsh birds, shorebirds, ecological integrity, and co-benefiets for people to identify Cape Romain, South Carolina as a high-priority site for conservation action. The second example in Colombia used information on migrant and resident birds to identify the Cauca Valley as a high priority site. The multi-level conceptual framework we describe is one pathway for identifying sites for implementation of local conservation actions that are guided by conservation priorities for migratory birds across their full annual cycle.

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bioRxiv2019

Metrics for conservation success: using the 'Bird-Friendliness Index' to evaluate grassland and aridland bird community resilience across the Northern Great Plains ecosystem

AimEvaluating conservation effectiveness is essential to protect at-risk species and to maximize the limited resources available to land managers. Over 60% of North American grassland and aridlands have been lost since the 1800s. Birds in these habitats are among the most imperiled in North America, yet most remaining habitats are unprotected. Despite the need to measure impact, conservation efforts on private and working lands are rarely evaluated, due in part to limited availability of suitable methods. LocationNorthern Great Plains MethodsWe developed a novel metric to evaluate grassland and aridland bird community response to habitat management practices, the Bird-Friendliness Index (BFI), consisting of density estimates of grassland and aridland birds weighted by conservation need and a functional diversity metric to incorporate resiliency. We used the BFI to inform three assessments: 1) a spatial prioritization to identify ecologically significant areas for grassland and aridland birds, 2) estimation of temporal trends in grassland and aridland bird community resilience, and 3) evaluation of the effects of land management practices on grassland and aridland bird communities. ResultsThe most resilient bird communities were found in the Prairie Potholes region of Alberta, Saskatchewan, northern Montana, and North Dakota, and the lowest BFI values in the southern and western regions of the Northern Great Plains. BFI values varied little over time on average, but trends varied regionally, largely in response to interannual relative variability in grassland and aridland bird densities. Main conclusionsBFI values increased in response to simulated habitat management, suggesting that practices recommended for use in bird-friendly grassland habitat management plans will increase the abundance and resilience of the grassland and aridland bird community, and will be detected using the BFI. The BFI is a tool by which conservationists and managers can carry out accountable conservation now and into the future.

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bioRxiv2019

Responses of global waterbird populations to climate change vary with latitude

While climate change continues to present a major threat to global biodiversity and ecosystems, most research on climate change impacts do not have the resolution to detect changes in species abundance and are often limited to temperate ecosystems. This limits our understanding of global responses in species abundance--a determinant of ecosystem function and services--to climate change including in the highly-biodiverse tropics. We address this knowledge gap by quantifying abundance responses to climate change in waterbirds, an indicator taxon of wetland biodiversity, at 6,822 sites between -55{degrees} and 64{degrees}. Using 1,303,651 count records since 1990 of 390 species, we show that with temperature increase, the abundance of species and populations decreased at lower latitudes, particularly in the tropics, but increased at higher latitudes. These contrasting responses to temperature increase according to latitude indicate potential global-scale poleward shifts of species abundance under climate change, providing empirical support for predictions by earlier studies. The negative responses to temperature increase in tropical species and populations are of conservation concern, as they are often also threatened by other anthropogenic factors. Our results suggest that existing biases in studies towards temperate regions could underestimate the impact of climate change on waterbirds and other species.

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bioRxiv2018

High-Resolution, Long-Term Trends in Relative Abundance from Spatial Modeling of Continent-Wide Bird Counts

Continent-wide bird counts by community volunteers provide valuable information about the conservation needs of many bird species. The statistical modeling techniques commonly used to analyze these counts provide robust long-term trend estimates from heterogeneous community science data at regional, national, and continental scales. Here we present a novel modeling framework that increases the spatial resolution of trend estimates, and reduces the computational burden of trend estimation, each by an order of magnitude. We demonstrate the approach with data for the American Robin (Turdus migratorius) from Audubon Christmas Bird Counts conducted between 1966 and 2017, and show that aggregate regional trend estimates from the proposed method align well with those from the current standard method. Thus, it appears that the proposed technique can provide reasonable large-scale trend estimates for users concerned with general patterns, while also providing higher resolution estimates for others examining correlates of abundance trends at finer spatial scales.

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bioRxiv2018

Recent trends in Tricolored Blackbird colony size: analysis of the 2008 through 2017 Triennial Statewide Surveys

Tricolored blackbird (Agelaius tricolor) is a colonial breeder, largely restricted to grasslands, wetlands, and agricultural habitats of California. Tricolored blackbird abundance declined considerably during the 20th century. Recent trends have been less clear, however, hindering efforts to evaluate the conservation needs of the species. We assessed trends in tricolored blackbird colony size using the 2008, 2011, 2014, and 2017 Triennial Tricolored Blackbird Statewide Survey, a community-science effort involving hundreds of volunteer observers. After accounting for variation in observer characteristics and survey effort, we found a clear, statistically significant decline in colony size of approximately -5% per year, which translated to a decrease in colony size of approximately -40% between 2008 and 2017. To the extent that colony size is proportional to total abundance, this decline translates to a species half-life of roughly 15 years. We conclude that tricolored blackbird is in considerable need of protection and recovery efforts.

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