Diana Stralberg

Climate change refugia are areas that are relatively buffered from contemporary climate change and may be important safe havens for wildlife and plants under anthropogenic climate change. Topographic variation is an important driver of thermal heterogeneity, but it is limited in relatively flat landscapes, such as the boreal plain and prairie regions of western Canada. Topographic variation within this region is mostly restricted to river valleys and hill systems, and their effects on local climates are not well documented. We sought to quantify thermal heterogeneity as a function of topography and vegetation cover within major valleys and hill systems across the boreal–grassland transition zone.Using iButton data loggers, we monitored local temperature at four hills and 12 river valley systems that comprised a wide range of habitats and ecosystems in Alberta, Canada (N = 240), between 2014 and 2020. We then modeled monthly temperature by season as a function of topography and diffe...

Distributions of landbirds in Canadian northern forests are expected to be affected by climate change, but it remains unclear which pathways are responsible for projected climate effects. Determining whether climate change acts indirectly through changing fire regimes and/or vegetation dynamics, or directly through changes in climatic suitability may allow land managers to address negative trajectories via forest management. We used SpaDES, a novel toolkit built in R that facilitates the implementation of simulation models from different areas of knowledge to develop a simulation experiment for a study area comprising 50 million ha in the Northwest Territories, Canada. Our factorial experiment was designed to contrast climate effects pathways on 64 landbird species using climate-sensitive and non-climate sensitive models for tree growth and mortality, wildfire, and landbirds. Climate-change effects were predicted to increase suitable habitat for 73% of species, resulting in average ...

Conservation of migratory shorebirds and waterfowl presents unique challenges due to extensive historic loss of wetland habitats, and current reliance on managed landscapes for wintering and migratory passage. We developed a spatially-explicit approach to estimate potential shorebird and waterfowl densities in California by integrating mapped habitat layers and statewide bird survey data with expert-based habitat rankings. Using these density estimates

Quantifying the relative contributions of environmental conditions and spatial factors to species distribution can help improve our understanding of the processes that drive diversity patterns. In this study, based on tree inventory, topography and soil data from a 20-ha stem-mapped permanent forest plot in Guangdong Province, China, we evaluated the influence of different ecological processes at different spatial scales using canonical redundancy analysis (RDA) at the community level and multiple linear regression at the species level. At the community level, the proportion of explained variation in species distribution increased with grid-cell sizes, primarily due to a monotonic increase in the explanatory power of environmental variables. At the species level, neither environmental nor spatial factors were important determinants of overstory species ’ distributions at small cell sizes. However, purely spatial variables explained most of the variation in the distributions of under...

Estimating the population abundance of landbirds is a challenging task complicated by the amount, type, and quality of available data. Avian conservationists have relied on population estimates from Partners in Flight (PIF), which primarily uses roadside data from the North American Breeding Bird Survey (BBS). However, the BBS was not designed to estimate population sizes. Therefore, we set out to compare the PIF approach with spatially explicit models incorporating roadside and off-road point-count surveys. We calculated population estimates for 81 landbird species in Bird Conservation Region 6 in Alberta, Canada, using land cover and climate as predictors. We also developed a framework to evaluate how the differences between the detection distance, time-of-day, roadside count, and habitat representation adjustments explain discrepancies between the 2 estimators. We showed that the key assumptions of the PIF population estimator were commonly violated in this region, and that the 2...

More than 80 percent of San Francisco Bay's original tidal wetlands have been altered or displaced, reducing available habitat for a range of tidal marsh-dependent species, including the Federally listed California Clapper Rail (Rallus longirostris obsoletus) and three endemic Song Sparrow (Melospiza melodia) subspecies. In the South Bay, many tidal marshes were converted to commercial salt ponds, which have since become among the most important Pacific coast sites for shorebirds, waterfowl and other waterbirds. Recently, however, over 6,000 ha of commercial salt ponds were sold to wildlife management agencies for creation and restoration of tidal marsh systems, which will result in a significant change in the Bay's wetland landscape. This situation creates a need to evaluate the interrelated and potentially conflicting habitat needs of a wide range of species, in order to inform priorities for wetland restoration and management. Using a combination of standardized bird surv...

This study examines the effect of rural residential development and landscape composition on breeding birds in Placer County’s foothill oak woodlands. Point count survey data were used to construct generalized linear models for individual species’ abundance or probability of occurrence, based on two sets of variables: GIS-derived landscape characteristics, including development density, oak woodland proportion, and habitat diversity; and field-collected local habitat parameters. We found that many species examined were sensitive to either development density or landscape composition at some distance between 250 and 4,000 m. Of the 48 breeding species common enough to analyze statistically, the occurrence of 24 species was significantly associated with landscape characteristics. Species shown to be associated with development density and/or urban edge proximity included the lark sparrow (-), Rufouscrowned sparrow (-), western meadowlark (-), black Phoebe (+), house finch (+) and west...

Populations of Canada Warbler (Cardellina canadensis) are declining in Canada’s Atlantic Northern Forest. Land conservancies and government agencies are interested in identifying areas to protect populations, while some timber companies wish to manage forests to minimize impacts on Canada Warbler and potentially create future habitat. We developed seven conservation planning scenarios using Zonation software to prioritize candidate areas for permanent land conservation (4 scenarios) or responsible forest management (minimizing species removal during forest harvesting while promoting colonization of regenerated forest; 3 scenarios). Factors used to prioritize areas included Canada Warbler population density, connectivity to protected areas, future climate suitability, anthropogenic disturbance, and recent Canada Warbler observations. We analyzed each scenario for three estimates of natal dispersal distance (5, 10, and 50 km). We found that scenarios assuming large dispersal distances...

The arrangement of habitat features via historical or contemporary events can strongly influence genomic and demographic connectivity, and in turn affect levels of genetic diversity and resilience of populations to environmental perturbation. The rusty blackbird (Euphagus carolinus) is a forested wetland habitat specialist whose population size has declined sharply (78%) over recent decades. The species breeds across the expansive North American boreal forest region, which contains a mosaic of habitat conditions resulting from active natural disturbance regimes and glacial history. We used landscape genomics to evaluate how past and present landscape features have shaped patterns of genetic diversity and connectivity across the species’ breeding range. Based on reduced-representation genomic and mitochondrial DNA, genetic structure followed four broad patterns influenced by both historical and contemporary forces: (1) an east–west partition consistent with vicariance during the last...

We used conventional and finite mixture removal models with and without time-varying covariates to evaluate availability given presence for 152 bird species using data from point counts in boreal North America. We found that the choice of model had an impact on the estimability of unknown model parameters and affected the bias and variance of corrected counts. Finite mixture models provided better fit than conventional removal models and better adjusted for count duration. However, reliably estimating parameters and minimizing variance using mixture models required at least 200–1,000 detections. Mixture models with time-varying proportions of infrequent singers were best supported across species, indicating that accounting for date- and time-related heterogeneity is important when combining data across studies over large spatial scales, multiple sampling time frames, or variable survey protocols. Our flexible and continuous time-removal modeling framework can be used to account for ...

The objectives of this study were to describe and evaluate potential drivers of genetic structure in Canadian breeding populations of the Ovenbird, Seiurus aurocapilla. We performed genetic analyses on feather samples of individuals from six study sites using nuclear microsatellites. We also assessed species identity and population genetic structure of quill mites (Acariformes, Syringophilidae). For male Ovenbirds breeding in three study sites, we collected light-level geolocator data to document migratory paths and identify the wintering grounds. We also generated paleohindcast projections from bioclimatic models of Ovenbird distribution to identify potential refugia during the last glacial maximum (LGM, 21,000 years before present) as a factor explaining population genetic structure. Birds breeding in the Cypress Hills (Alberta/Saskatchewan) may be considered a distinct genetic unit, but there was no evidence for genetic differentiation among any other populations. We found relati...

As most regions of the earth transition to altered climatic conditions, new methods are needed to identify refugia and other areas whose conservation would facilitate persistence of biodiversity under climate change. We compared several common approaches to conservation planning focused on climate resilience over a broad range of ecological settings across North America and evaluated how commonalities in the priority areas identified by different methods varied with regional context and spatial scale. Our results indicate that priority areas based on different environmental diversity metrics differed substantially from each other and from priorities based on spatiotemporal metrics such as climatic velocity. Refugia identified by diversity or velocity metrics were not strongly associated with the current protected area system, suggesting the need for additional conservation measures including protection of refugia. Despite the inherent uncertainties in predicting future climate, we f...

... OF TIDAL-MARSH BREEDING BIRDS IN THE SAN FRANCISCO BAY ESTUARY HILDIE SPAUTZ, NADAV NUR, DIANA STRALBERG, AND ... Mientras que los mejores modelos con-tenían tanto variables locales como de paisaje, las cuatro especies fueron también bien ...

Geoffrey R. Geupel, W. David Shuford, Diana Stralberg, Grant Ballard, Dennis Jongsomjit, Chris J. Rintoul, Mark Herzog, Douglas Moody, Catherine Hickey PRBO Conservation Science 3820 Cypress Drive #11 Petaluma, CA 94954 ggeupel@prbo.org ... Chapter 1. California Bird ...

Geoffrey R. Geupel, W. David Shuford, Diana Stralberg, Grant Ballard, Dennis Jongsomjit, Chris J. Rintoul, Mark Herzog, Douglas Moody, Catherine Hickey PRBO Conservation Science 3820 Cypress Drive #11 Petaluma, CA 94954 ggeupel@prbo.org ... Chapter 1. California Bird ...

Species distribution models (SDMs) based on climate variables are often used to quantify and describe the spatial distributions of species under current and projected future climate conditions. While such models are generally developed at the continental level for the purpose of projecting broad-scale range shifts, there is an increasing demand for projections at scales fine enough to inform land-management decisions and conservation priorities. In a state as topographically complex as California, significant downscaling is required to adapt general circulation model (GCM) projections to conservation planning applications. We used 30-km regional climate model projections for 2038-2070 with boundary conditions taken from two GCMs under the SRES A2 (high CO2 emissions) scenario and downscaled them to an 800-m resolution based on PRISM climate normals for 1970-2000. Bioclimatic variables derived from temperature and precipitation normals were used to model the distributions of 203 California landbird taxa and to identify the species whose distributions are most likely to be affected by climate change. To synthesize the geographic implications of these individual SDM projections, we used the systematic conservation planning software Zonation to identify priority areas for avian conservation based on current and projected future distributions of all taxa. We used the California Bird Species of Special Concern framework to weight species according to conservation status, compared two prioritization algorithms, and incorporated SDM and climate model uncertainty into the prioritization exercise. The resulting areas of high conservation value were intersected with current protected areas to identify conservation gaps. Portions of the north and central coast were identified as consistent yet largely unprotected “hotspots” for current and future bird distributions. This approach illustrates how species distribution modeling, coupled with planning tools such as Zonation, can help to frame geographical priorities for current and future conservation action.

ABSTRACT Background/Question/Methods The large uncertainty surrounding the effects of sea-level rise and climate change on tidal marsh habitats and the species that depend on them exacerbates the difficulty in planning effective conservation and restoration efforts. To help conservation practitioners address these effects, we modeled the distribution and abundance of tidal marsh bird species in the San Francisco Estuary every twenty years between 2010 and 2110 in relation to projected changes in sea-level rise, salinity, and sediment availability. These distributions were projected for four future scenarios with assumptions of low or high suspended sediment concentrations and low or high rates of sea-level rise (0.52 m or 1.65 m/100 yr) to assess the sensitivity of models to uncertainty in future conditions. We used the projections of bird populations to develop spatial priorities for conservation and restoration using Zonation conservation planning software. We explicitly incorporated between-scenario uncertainties into our future prioritization and tested whether spatial priorities changed when we included just current or both current and future tidal marsh bird distribution projections. Results/Conclusions We project overall tidal marsh bird population declines from current levels due to the conversion of high and mid-marsh habitat to low-marsh and mudflats and changes in spring and summer salinity. High sea-level rise scenarios had the biggest impact on bird populations, although the effects were muted under high sediment availability scenarios. There was considerable variation in bird population projections among the four future scenarios we tested and the uncertainty tended to increase from 2030 to 2110. We found substantial differences in our spatial prioritization depending on whether future distributions were included, indicating that effective conservation and restoration management will need to consider the effects of climate change. Our results demonstrate how uncertainty due to future climate change can be explicitly incorporated into conservation planning efforts by prioritizing sites with high quality habitat and low uncertainty in future projections. To demonstrate how our results can be used to support management decisions, we identified important locations in which restoration by breaching levees would most effectively provide long term benefits to tidal marsh bird populations. We used the results from our study to develop a decision support tool where interactive maps of the results can be viewed, queried and downloaded at www.prbo.org/sfbayslr.

Background/Question/Methods Using comprehensive avian survey data (1996-2005) and data layers derived primarily from a National Park Service vegetation map, we developed spatial models of species distribution and diversity within areas managed by the Golden Gate National Recreation Area (GOGA) and the Point Reyes National Seashore. Our objective was to assist GOGA and the Golden Gate National Parks Conservancy (GGNPC) with resource planning and management using landbirds as indicators. We used a focal species approach to select appropriate avian metrics, including the occurrence of disturbance-sensitive species, and species richness of focal species by habitat. Generalized additive models were used to represent non-linear relationships between vegetation and landscape characteristics and the distribution of avian species. Models were used to develop spatial predictions of species occurrence and diversity within the parks. Combining models for different management-sensitive species r...