The border between Canada and the United States poses jurisdictional challenges when it comes to consistently implementing science-based conservation of forests and their biological communities. Through a partnership with the Sustainable Forestry Initiative, Boreal Avian Modelling Project, and American Bird Conservancy, we developed a co-production framework to conduct research that will inform forest management practices for bird conservation in the cross-border region of Bird Conservation Region 12. Our framework first responds to the needs of resource managers and other perceived stakeholders, while investing in relationship-building for long term trust as a foundation for future partnerships with Indigenous rights holders and landowners. Our central question was: How can sustainably managed forests create and/or maintain high quality breeding habitat to support forest bird populations that are resilient to climate change? Engaging with experts in Canada and the United States, we found that the main driver for addressing our central question was our limitation in connecting bird population responses to specific forest management practices. We describe how experts are contributing avian count and forest inventory data that researchers will use to produce a requested decision-support tool. We continue to engage with land managers to link forest resource inventory data to specific forest management practices and refine the components of products by including more diverse perspectives.
To recover species at risk, it is necessary to identify habitat critical to their recovery. Challenges for species with large ranges (thousands of square kilometres) include delineating management unit boundaries within which habitat use differs from other units, along with assessing any differences among units in amounts of and threats to habitat over time. We developed a reproducible framework to support identification of critical habitat for wide-ranging species at risk. The framework (i) reviews species distribution and life history; (ii) delineates management units across the range; (iii) evaluates and compares current and (iv) potential future habitat and population size and (v) prioritizes areas within management units based on current and future conditions under various scenarios of climate change and land-use. We used Canada Warbler ( Cardellina canadensis ) and Wood Thrush ( Hylocichla mustelina ) in Canada as case studies. Using geographically weighted regression models and cluster analysis to measure spatial variation in model coefficients, we found geographic differences in habitat association only for Canada Warbler. Using other models to predict current habitat amount for each species in different management units, then future habitat amount under land use and climate change, we projected that: (1) Canada Warbler populations would decrease in Alberta but increase in Nova Scotia and (2) Wood Thrush populations would increase under most scenarios run in Quebec, New Brunswick and Nova Scotia, but not in Ontario. By comparing results from future scenarios and spatial prioritization exercises, our framework supports identification of critical habitat in ways that incorporate climate and land-use projections.
Climate change presents a major threat to biodiversity globally. Northern ecosystems, such as Canada's boreal forest, are predicted to experience particularly severe climate-induced changes. These changes may reduce the carrying capacity and habitat suitability of the boreal forest for many wildlife species. Boreal birds are susceptible to both direct and indirect effects of climate change, and several studies have predicted northward shifts in species distributions as temperatures become warmer. We forecasted spatially-explicit changes in the densities of 72 boreal landbird species using integrated climate change projections and a forest dynamics model in the Taiga Plains ecozone of the Northwest Territories (NT), Canada, over the 2011–2091 horizon. We 1) identified ''winner,'' ''loser,'' and ''bellringer'' species over short (2031) and long-term (2091) forecasts, 2) mapped landbird range and density changes under three contrasting Global Circulation Models (GCMs), and 3) quantify differences in landbird density predictions across a latitudinal gradient. Species that showed a moderate increase or decrease in their predicted abundance were considered ''winners'' and ''losers,'' respectively. Species that showed a marked increase or decrease – a doubling or halving – of their predicted abundance in all three GCMs, were termed ''bellringers''. From 2011–2031, only 2/72 (2.8%) were considered winners, and 3/72 (4.2%) were losers. From 2011–2091, the abundance of more species was predicted to change: 26/72 (36.1%) were winners, and 10/72 species (13.9%) were losers. Four species were considered bellringers: Gray-cheeked Thrush, White-crowned Sparrow, Fox Sparrow, and American Tree Sparrow. Overall, projected range shifts were strongly oriented along a southeast-to-northwest axis. Shifts to the north and south were evenly distributed among all three GCMs. Our results suggest that future climate-mitigated distribution shifts and population declines of boreal landbirds will require targeted conservation actions. They also highlight the importance of the NT as a potential refugium for many boreal-breeding landbird species in Canada.
Context Industrial development in Canada’s boreal forest creates cumulative environmental effects on biodiversity. Some effects may be scale-dependent, creating uncertainty in understanding and hindering effective management. Objectives We estimated cumulative effects of energy sector development on distributions of sixteen migratory songbird species at multiple spatial scales within the boreal region of Alberta, Canada, and evaluated evidence for scale domains in species responses. Methods We used a hierarchical, multi-scale sampling and modelling framework to compare effects of oil and gas footprint on songbirds at five spatial scales. We used Bayesian Lasso to facilitate direct comparison of parameter estimates across scales, and tested for differences in grouped parameter estimates among species. Results We found consistent scale-dependent patterns across species, showing variable responses to development occurring at the smallest scale, little effect at intermediate scales, and stronger, mainly positive effects at the largest scales. Differences in grouped parameter estimates across scales showed strong evidence for scale domains in the response of songbirds to energy sector development. Conclusions We concluded that variable effects at the smallest scale represented individual habitat selection, while larger scale positive effects reflected expanding distributions of open habitat- and disturbance-associated species in areas of high oil and gas footprint. Our results show that single-scale analyses do not reflect population processes occurring at other scales. Future research on linking patterns at different scales is required to fully understand cumulative effects of land use change on wildlife populations.
Bird monitoring in North America over several decades has generated many open databases, housing millions of structured and semi-structured bird observations. These provide the opportunity to estimate bird densities and population sizes, once variation in factors such as underlying field methods, timing, land cover, proximity to roads, and uneven spatial coverage are accounted for. To facilitate integration across databases, we introduce NA-POPS: Point Count Offsets for Population Sizes of North American Landbirds. NA-POPS is a large-scale, multi-agency project providing an open-source database of detectability functions for all North American landbirds. These detectability functions allow the integration of data from across disparate survey methods using the QPAD approach, which considers the probability of detection (q) and availability (p) of birds in relation to area (a) and density (d). To date, NA-POPS has compiled over 7.1 million data points spanning 292 projects from across North America, and produced detectability functions for 338 landbird species. Here, we describe the methods used to curate these data and generate these detectability functions, as well as the open-access nature of the resulting database.
Conservation approaches that efficiently protect multiple values, such as the umbrella species concept, have been widely promoted with expected dramatic ecosystem changes. Due to its social and cultural importance, and recent declining trends, boreal populations of woodland caribou have been suggested as potential umbrella species for other declining taxa, such as boreal landbirds. We propose a generic pixel-based umbrella index that focuses on fine-grained habitat overlaps. In light of ongoing conservation efforts worldwide implementing area-based targets (e.g., 30% by 2030), we used a random neutral model as baseline, as opposed to a no-conservation scenario, which has been used elsewhere. We found that the conservation efficiency of caribou as an umbrella for 71 co-occurring landbirds-three of which are priority species-in the Northwest Territories, Canada, is generally lower than our random model, as 53% of the species presented negative umbrella index medians with the interquartile range not overlapping zero. We conclude that in cases where area-based targets drive decision-making and the issue at stake involves identifying which areas to conserve-not whether to conserve-woodland caribou may be a leaky umbrella for most co-occurring landbird species and these might need complementary conservation actions to be brought in from the rain.
Context Oil and gas activity is increasing in the western boreal forest of North America. To manage cumulative effects of this industry, a better quantification of footprint effects on wildlife is needed. Objectives We used point-count surveys to evaluate how well footprint amounts within 150 m, and proximity to seismic lines, pipelines, well sites, roads, and energy facilities predicted the abundance of 48 bird species. Methods We developed models for each species, evaluating the best functional forms for different footprint effects, then predicted how different model structures influenced estimates of regional population size. Results Most species exhibited at least one nonlinear response to footprint amount (79% of species) or distance (88%). Species associated with older coniferous forests decreased more often with increased footprint amount and closer proximity to footprint, while species associated with open lands and young forests increased with greater footprint and closer proximity. In one-third of species, bird abundance versus distance changed from a positive to negative relationship (or reverse) at a threshold distance from at least one footprint. Models based on footprint proximity had better fit than those based on footprint amount for 29 of 48 species, but both model types produced similar population estimates. Conclusions Both footprint amount and proximity models were useful for assessing cumulative effects on wildlife and mechanisms causing change. Models of distance to footprint can provide evidence of positive or negative edge effects for developing management buffers. Models of footprint amount provide important information on functional changes in habitat.
Prescribed fire is used throughout fire-prone landscapes to conserve biodiversity. Current best practice in managing savanna systems advocates methods based on the assumption that increased fire-mediated landscape heterogeneity (pyrodiversity) will promote biodiversity. However, considerable knowledge gaps remain in our understanding of how savanna wildlife responds to the composition and configuration of pyrodiverse landscapes. The effects of pyrodiversity on functional diversity have rarely been quantified and assessing this relationship at a landscape scale that is commensurate with fire management is important for understanding mechanisms underlying ecosystem resilience. Here, we assess the impact of spatiotemporal variation in a long-term fire regime on avian diversity in North West Province, South Africa. We examined the relationship between (1) species richness, (2) three indices of functional diversity (i.e., functional richness, functional evenness, and functional dispersion) and four measures of pyrodiversity, the spatial extents of fire age classes, and habitat type at the landscape scale. We then used null models to assess differences between observed and expected functional diversity. We found that the proportion of newly burned (<1-yr post-fire), old, unburned (≥10 yr post-fire), and woodland habitat on the landscape predicted species and functional richness. Species richness also increased with the degree of edge contrast between patches of varying fire age, while functional dispersion increased with the degree of patch shape complexity. Lower than expected levels of functional richness suggest that habitat filtering is occurring, resulting in functional redundancy across our study sites. We demonstrate that evaluating functional diversity and redundancy is an important component of conservation planning as they may contribute to previously reported fire resilience. Our findings suggest that it is the type and configuration, rather than the diversity, of fire patches on the landscape that promote avian diversity and conserve ecological functions. A management approach is needed that includes significant coverage of adjacent newly burned and older, unburned savanna habitat; the latter, in particular, is inadequately represented under current burning practices.
Effects of logging on species composition in tropical rainforests are well known but may fail to reveal key changes in species interactions. We used nitrogen stable-isotope analysis of 73 species of understory birds to quantify trophic responses to repeated intensive logging of rainforest in northern Borneo and to test 4 hypotheses: logging has significant effects on trophic positions and trophic-niche widths of species, and the persistence of species in degraded forest is related to their trophic positions and trophic-niche widths in primary forest. Species fed from higher up the food chain and had narrower trophic-niche widths in degraded forest. Species with narrow trophic-niche widths in primary forest were less likely to persist after logging, a result that indicates a higher vulnerability of dietary specialists to local extinction following habitat disturbance. Persistence of species in degraded forest was not related to a species' trophic position. These results indicate changes in trophic organization that were not apparent from changes in species composition and highlight the importance of focusing on trophic flexibility over the prevailing emphasis on membership of static feeding guilds. Our results thus support the notion that alterations to trophic organization and interactions within tropical forests may be a pervasive and functionally important hidden effect of forest degradation. Flexibilidad Trofica y la Persistencia de Aves de Sotobosque en un Bosque Lluvioso Talado IntensivamenteResumen Los efectos de la tala sobre la composicion de especies en bosques lluviosos tropicales son bien conocidos pero pueden fallar en la revelacion de cambios clave en las interacciones de especies. Utilizamos analisis de isotopos estables de nitrogeno de 73 especies de aves de sotobosque para cuantificar las respuestas troficas a la tala intensiva del bosque lluvioso en el norte de Borneo y para probar 4 hipotesis: la tala tiene efectos significativos sobre posiciones troficas y la amplitud de nicho de las especies, y la persistencia de especies en el bosque degradado esta relacionado con sus posiciones troficas y amplitud de nicho trofico en el bosque primario. Las especies se alimentaron mas arriba en la cadena trofica y tuvieron nichos mas angostos en el bosque degradado. Las especies con nichos angostos en bosques primarios tuvieron menor probabilidad de persistir despues de la tala, resultado que indica que especies con dietas especializadas tienen mayor vulnerabilidad a la extincion local despues de una perturbacion de habitat. La persistencia de especies en bosque degradado no se relaciono con la posicion trofica. Este resultado indica cambios en la organizacion trofica que no fueron aparentes con los cambios en la composicion de especies y resaltan la importancia de concentrase en la flexibilidad trofica en vez del enfasis prevaleciente en la membresia de gremios alimenticios estaticos. Por lo tanto, nuestros resultados soportan la nocion de que las alteraciones de la organizacion trofica y las interacciones en los bosques tropicales pueden ser un efecto oculto, dominante e importante funcionalmente, de la degradacion de bosques.
Selective logging is a major driver of rainforest degradation across the tropics. Two competing logging strategies are proposed to meet timber demands with the least impact on biodiversity: land sharing, which combines timber extraction with biodiversity protection across the concession; and land sparing, in which higher intensity logging is combined with the protection of intact primary forest reserves. We evaluate these strategies by comparing the abundances and species richness of birds, dung beetles and ants in Borneo, using a protocol that allows us to control for both timber yield and net profit across strategies. Within each taxonomic group, more species had higher abundances with land-sparing than land-sharing logging, and this translated into significantly higher species richness within land-sparing concessions. Our results are similar when focusing only on species found in primary forest and restricted in range to Sundaland, and they are independent of the scale of sampling. For each taxonomic group, land-sparing logging was the most promising strategy for maximizing the biological value of logging operations.
Southeast Asia is a hotspot of imperilled biodiversity, owing to extensive logging and forest conversion to oil palm agriculture. The degraded forests that remain after multiple rounds of intensive logging are often assumed to be of little conservation value; consequently, there has been no concerted effort to prevent them from being converted to oil palm. However, no study has quantified the biodiversity of repeatedly logged forests. We compare the species richness and composition of birds and dung beetles within unlogged (primary), once-logged and twice-logged forests in Sabah, Borneo. Logging had little effect on the overall richness of birds. Dung beetle richness declined following once-logging but did not decline further after twice-logging. The species composition of bird and dung beetle communities was altered, particularly after the second logging rotation, but globally imperilled bird species (IUCN Red List) did not decline further after twice-logging. Remarkably, over 75 per cent of bird and dung beetle species found in unlogged forest persisted within twice-logged forest. Although twice-logged forests have less biological value than primary and once-logged forests, they clearly provide important habitat for numerous bird and dung beetle species. Preventing these degraded forests from being converted to oil palm should be a priority of policy-makers and conservationists.