Risk to North American birds from climate change‐related threats

Multispecies migratory connectivity indicates hemispheric-scale risk to bird populations from global change

Global agreements to reduce the extinction risk of migratory species depend critically on intersecting migratory connectivity-the linking of individuals between regions in different seasons-and spatial patterns of environmental change. Here we integrate movement data from >329,000 migratory birds of 112 species to develop a parameter representing exposure to global change: multispecies migratory connectivity. We then combine exposure with projected climate and land-cover changes as a measure of hazard and species conservation assessment scores as a metric of vulnerability to estimate the relative risk of migratory bird population declines across the Western Hemisphere. Multispecies migratory connectivity (exposure) is the strongest driver of risk relative to hazard and vulnerability, indicating the importance of synthesizing connectivity across species to comprehensively assess risk. Connections between breeding regions in Canada and non-breeding regions in South America are at the greatest risk, which underscores the particular susceptibility of long-distance migrants. Over half (54%) of the connections categorized as very high risk include breeding regions in the eastern United States. This three-part framework serves as an ecological risk assessment designed specifically for migratory species, providing both decision support for global biodiversity conservation and opportunities for intergovernmental collaboration to sustain migratory bird populations year-round.

A 19th Century Stormwrecked Black-Capped Petrel From Vermont Offers Insight Into Historical Vagrancy Processes

Specimens stored within museum collections are increasingly leveraged to reconstruct historical baselines to both decipher the legacies of past anthropogenic impacts and anticipate the consequences of future climate change on species distributions. However, the research significance of such collections can be severely constrained based on their curation histories, resulting in data being forgotten, if not lost entirely. In this Nature Note, we report the unexpected presence of a mislabeled Black-capped Petrel (Pterodroma hasitata) specimen in the historical Middlebury College Vertebrate Natural History collection, potentially representing the rediscovery of a lost specimen reported from Vermont following the 1893 New York City Hurricane. We conducted archival research at multiple institutions to substantiate the reporting of a Black-capped Petrel specimen that was "missing" from Vermont in 1893, as noted in the Vermont Breeding Bird Atlas. We further substantiated the 19th-century age of this specimen through X-ray fluorescence analysis of mercury and arsenic of more than 200 whole bird bodies and feathers across the majority of the Middlebury College collection as part of an environmental health and safety assessment. This record expands the known vagrant range of the Black-capped Petrel. This research likewise highlights the critical role of small museum collections play in piecing together historical datasets and informing modern conservation, emphasizing the importance of their preservation and digitization.

The effect of global warming on the Australian endemic orchid Cryptostylis leptochila and its pollinator

Ecological stability together with the suitability of abiotic conditions are crucial for long-term survival of any organism and the maintenance of biodiversity and self-sustainable ecosystems relies on species interactions. By influencing resource availability plants affect the composition of plant communities and ultimately ecosystem functioning. Plant-animal interactions are very complex and include a variety of exploitative and mutualistic relationships. One of the most important mutualistic interactions is that between plants and their pollinators. Coevolution generates clustered links between plants and their pollen vectors, but the pollination and reproductive success of plants is reduced by increase in the specialization of plant-animal interactions. One of the most specialized types of pollination is sexual deception, which occurs almost exclusively in Orchidaceae. In this form of mimicry, male insects are attracted to orchid flowers by chemical compounds that resemble insect female sex pheromones and pollinate the flowers during attempted copulations. These interactions are often species-specific with each species of orchid attracting only males of one or very few closely related species of insects. For sexually deceptive orchids the presence of a particular pollen vector is crucial for reproductive success and any reduction in pollinator availability constitutes a threat to the orchid. Because global warming is rapidly becoming the greatest threat to all organisms by re-shaping the geographical ranges of plants, animals and fungi, this paper focuses on predicting the effect of global warming on Cryptostylis leptochila, a terrestrial endemic in eastern Australia that is pollinated exclusively via pseudo copulation with Lissopimpla excelsa. As a species with a single pollinator this orchid is a perfect model for studies on the effect of global warming on plants and their pollen vectors. According to our predictions, global warming will cause a significant loss of suitable niches for C. leptochila. The potential range of this orchid will be 36%-75% smaller than currently and as a result the Eastern Highlands will become unsuitable for C. leptochila. On the other hand, some new niches will become available for this species in Tasmania. Simultaneously, climate change will result in a substantial expansion of niches suitable for the pollinator (44-82%). Currently ca. 71% of the geographical range of the orchid is also suitable for L. excelsa, therefore, almost 30% of the areas occupied by C. leptochila already lack the pollen vector. The predicted availability of the pollen vector increased under three of the climate change scenarios analysed. The predicted habitat loss is a serious threat to this orchid even with the potential colonization of Tasmania by this plant. In the reduced range of C. leptochila the pollen vector will also be present assuring fruit set in populations of this orchid. The genetic pool of the populations in New South Wales and Queensland will probably be lost.

Amount of bird suitable areas under climate change is modulated by morphological, ecological and geographical traits

Biodiversity is already experiencing the effects of climate change through range expansion, retraction, or relocation, potentializing negative effects of other threats. Future projections already indicate richness reduction and composition modifications of bird communities due to global warming, which may disrupt the provision of key ecological services to ecosystem maintenance. Here, we systematically review the effect of morphological, ecological, and geographical traits on the amount of future suitable area for birds worldwide. Specifically, we tested whether body mass, diet, habitat type, movement pattern, range size, and biogeographic realm affect birds' suitable area. Our search returned 75 studies that modeled the effects of climate change on 1,991 bird species. Our analyses included 1,661 species belonging to 128 families, representing 83% of the total, for which we were able to acquire all the six traits. The proportion of birds' suitable area was affected by range size, body mass, habitat type, and biogeographic realm, while diet and movement pattern showed lower relative importance and were not included in our final model. Contrary to expectations, the proportion of birds' suitable area was negatively related to range size, which may be explained by higher climatic stability predicted in certain areas that harbor species with restricted distribution. In contrast, we observed that birds presenting higher body mass will show an increase of the proportion of suitable area in the future. This is expected due to the high exposure of smaller birds to environmental changes and their difficulty to keep thermoregulation. Our results also indicated a low proportion of suitable area to forest-dependent birds, which is in accordance with their higher vulnerability due to specific requirements for reproduction and feeding. Finally, the proportion of suitable area was low for birds from Oceania, which is expected since the region encompasses small islands isolated from continents, preventing their species from reaching new suitable areas. Our study highlights that different traits should be considered when assessing extinction risk of species based on future projections, helping to improve bird conservation, especially the most vulnerable to climate change.

Mapping breeding bird species richness at management-relevant resolutions across the United States

Human activities alter ecosystems everywhere, causing rapid biodiversity loss and biotic homogenization. These losses necessitate coordinated conservation actions guided by biodiversity and species distribution spatial data that cover large areas yet have fine-enough resolution to be management-relevant (i.e., ≤5 km). However, most biodiversity products are too coarse for management or are only available for small areas. Furthermore, many maps generated for biodiversity assessment and conservation do not explicitly quantify the inherent tradeoff between resolution and accuracy when predicting biodiversity patterns. Our goals were to generate predictive models of overall breeding bird species richness and species richness of different guilds based on nine functional or life-history-based traits across the conterminous United States at three resolutions (0.5, 2.5, and 5 km) and quantify the tradeoff between resolution and accuracy and, hence, relevance for management of the resulting biodiversity maps. We summarized 18 years of North American Breeding Bird Survey data (1992-2019) and modeled species richness using random forests, including 66 predictor variables (describing climate, vegetation, geomorphology, and anthropogenic conditions), 20 of which we newly derived. Among the three spatial resolutions, the percentage variance explained ranged from 27% to 60% (median = 54%; mean = 57%) for overall species richness and 12% to 87% (median = 61%; mean = 58%) for our different guilds. Overall species richness and guild-specific species richness were best explained at 5-km resolution using ~24 predictor variables based on percentage variance explained, symmetric mean absolute percentage error, and root mean square error values. However, our 2.5-km-resolution maps were almost as accurate and provided more spatially detailed information, which is why we recommend them for most management applications. Our results represent the first consistent, occurrence-based, and nationwide maps of breeding bird richness with a thorough accuracy assessment that are also spatially detailed enough to inform local management decisions. More broadly, our findings highlight the importance of explicitly considering tradeoffs between resolution and accuracy to create management-relevant biodiversity products for large areas.

Assessing Pathways of Climate Change Effects in SpaDES: An Application to Boreal Landbirds of Northwest Territories Canada

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 net gain of 7.49 million ha across species. We observed higher species turnover in the northeastern, south-central (species loss), and western regions (species gain). Importantly, we found that most of the predicted differences in net area of occupancy across models were attributed to direct climate effects rather than simulated vegetation change, despite a similar relative importance of vegetation and climate variables in landbird models. Even with close to a doubling of annual area burned by 2100, and a 600 kg/ha increase in aboveground tree biomass predicted in this region, differences in landbird net occupancy across models attributed to climate-driven forest growth were very small, likely resulting from differences in the pace of vegetation and climate changes, or vegetation lags. The effect of vegetation lags (i.e., differences from climatic equilibrium) varied across species, resulting in a wide range of changes in landbird distribution, and consequently predicted occupancy, due to climate effects. These findings suggest that hybrid approaches using statistical models and landscape simulation tools could improve wildlife forecasts when future uncoupling of vegetation and climate is anticipated. This study lays some of the methodological groundwork for ecological adaptive management using the new platform SpaDES, which allows for iterative forecasting, mixing of modeling paradigms, and tightening connections between data, parameterization, and simulation.