Should Species Distribution Models Account for Spatial Autocorrelation? A Test of Model Projections Across Eight Millennia of Climate Change

Aim: The distributions of many organisms are spatially autocorrelated, but it is unclear whether including spatial terms in species distribution models (SDMs) improves projections of species distributions under climate change. We provide one of the first comparative evaluations of the ability of a purely spatial SDM, a purely non-spatial SDM and a SDM that combines spatial and environmental information to project species distributions across eight millennia of climate change. Location: Eastern North America. Methods: To distinguish between the importance of climatic versus spatial explanatory variables we fit three Bayesian SDMs to modern occurrence data for Fagus and Tsuga, two tree genera whose distributions can be reliably inferred from fossil pollen: a spatially varying intercept model, a non-spatial model with climatic variables and a spatially varying intercept plus climate model. Using palaeoclimate data with a high temporal resolution, we hindcasted the SDMs in 1000-year time steps for 8000 years, and compared model projections with palynological data for the same periods. Results: For both genera, spatial SDMs provided better fits to the calibration data, more accurate predictions of a hold-out validation dataset of modern trees and higher variance in current predictions and hindcasted projections than non-spatial SDMs. Performance of non-spatial and spatial SDMs according to the area under the receiver operating curve varied by genus. For both genera, false negative rates between non-spatial and spatial models were similar, but spatial models had lower false positive rates than non-spatial models. Main conclusions: The inclusion of computationally demanding spatial random effects in SDMs may be warranted when ecological or evolutionary processes prevent taxa from shifting their distributions or when the cost of false positives is high.Organismic and Evolutionary Biolog

Global synthesis of conservation studies reveals the importance of small habitat patches for biodiversity

Island biogeography theory posits that species richness increases with island size and decreases with isolation. This logic underpins much conservation policy and regulation, with preference given to conserving large, highly connected areas, and relative ambivalence shown toward protecting small, isolated habitat patches. We undertook a global synthesis of the relationship between the conservation value of habitat patches and their size and isolation, based on 31 systematic conservation planning studies across four continents. We found that small, isolated patches are inordinately important for biodiversity conservation. Our results provide a powerful argument for redressing the neglect of small, isolated habitat patches, for urgently prioritizing their restoration, and for avoiding simplistic application of island biogeography theory in conservation decisions.Peer reviewe

Site covs GFDLB1b

Covariates file for future predictions of species abundances based on the CNRM climate projections. All covariates as described in "Site covs.Roberts et al. 2019 EcoApps.csv" file except that temperature (TMN, TMX, dDMN, dTMX) data are sampled from future predictions according to the GFDLB1 scenario

Trophic cascades in the western Ross Sea, Antarctica: revisited

We investigated mesopredator effects on prey availability in the Ross Sea, Antarctica, as - sessing the reasons why Adélie penguin Pygoscelis adeliae foraging trip duration (FTD) increases and diet changes from krill to fish as numbers of foraging penguins and competing cetaceans increase in the penguins’ foraging area. To investigate penguins’ seasonally changing FTD as a function of foraging-population size—previously investigated indirectly—we used bio-logging to determine the penguins’ 3-dimensional foraging volume, while an autonomous glider quantified the depth, abundance, and distribution of potential prey. As numbers of foraging penguins and cetaceans increased, penguins spent more time on foraging trips, traveling farther and deeper, and their diet included more fish, as average maximum depth of krill increased from 45 to 65 m, and that of small fish also deepened, but only from 51 to 57 m. With a need to forage at greater depths for in creasingly over lapping prey, the penguins consumed more of the energydense fish. Krill depth was negatively correlated with chlorophyll (a proxy for krill food), indi cating an uncoupling between the two and the overwhelming importance of predation avoidance by the krill relative to food acquisition. Results support the hypotheses that (1) predators remove the grazers from Ross Sea surface waters, controlling their ver - tical distributions; and (2) the food web has a ‘waspwaist’ structure, in which middle- and upper-trophic levels are controlled top-down, whereas phytoplank - ton production and accumulation are regulated bottom-up, largely independent of grazer control. Ross Sea models need revision to reflect this food web structure

Potential Impacts of Climate Change on Biodiversity and Ecosystem Services in the San Francisco Bay Area

The San Francisco Bay Area contains a rich array of plant and animal biodiversity and an extensive open space network, embedded within a major metropolitan area. Terrestrial habitats in the San Francisco Bay Area support a wide range of ecosystem services, including carbon storage, forage production, enhanced water supply and quality, crop pollination, and outdoor recreation. The distribution of habitats and plant and animal species is strongly influenced by spatial variation in climate, and is thus expected to change in response to changes in regional and global climate. Current research suggests that most vegetation types will shift toward the coast, especially under scenarios with warmer and drier conditions; range contractions and reduced diversity are projected for California endemic plants in the Bay Area. Bird communities are projected to undergo significant reorganization, leading to altered interactions and community structure. Improved modeling at fine spatial scales represents an important priority to reduce uncertainty in these projections. Climate change is expected to strongly affect ecosystem services. Carbon storage in soils and vegetation could contribute to California’s carbon emissions reduction strategy, but current models project reduced carbon storage in trees due to climate change. Altered agricultural management strategies, including conversion to perennial crops, have the potential to increase soil carbon storage. Climate change impacts on vegetation, hydrology and habitat integrity may negatively affect fire regimes, forage production, water supplies, crop pollination services, and outdoor recreation and quality of life in the San Francisco Bay Area, but few specific projections are available. Strategic conservation planning in the Bay Area is under way to enhance biodiversity conservation through continued open space acquisition. Conservation of heterogeneous landscapes will provide resilience in the face of climate change. Improved understanding of projected climate change impacts on natural habitats will contribute to the development of regional adaptation strategies

Potential Impacts of Climate Change on Biodiversity and Ecosystem Services in the San Francisco Bay Area

The San Francisco Bay Area contains a rich array of plant and animal biodiversity and an extensive open space network, embedded within a major metropolitan area. Terrestrial habitats in the San Francisco Bay Area support a wide range of ecosystem services, including carbon storage, forage production, enhanced water supply and quality, crop pollination, and outdoor recreation. The distribution of habitats and plant and animal species is strongly influenced by spatial variation in climate, and is thus expected to change in response to changes in regional and global climate. Current research suggests that most vegetation types will shift toward the coast, especially under scenarios with warmer and drier conditions; range contractions and reduced diversity are projected for California endemic plants in the Bay Area. Bird communities are projected to undergo significant reorganization, leading to altered interactions and community structure. Improved modeling at fine spatial scales represents an important priority to reduce uncertainty in these projections. Climate change is expected to strongly affect ecosystem services. Carbon storage in soils and vegetation could contribute to California’s carbon emissions reduction strategy, but current models project reduced carbon storage in trees due to climate change. Altered agricultural management strategies, including conversion to perennial crops, have the potential to increase soil carbon storage. Climate change impacts on vegetation, hydrology and habitat integrity may negatively affect fire regimes, forage production, water supplies, crop pollination services, and outdoor recreation and quality of life in the San Francisco Bay Area, but few specific projections are available. Strategic conservation planning in the Bay Area is under way to enhance biodiversity conservation through continued open space acquisition. Conservation of heterogeneous landscapes will provide resilience in the face of climate change. Improved understanding of projected climate change impacts on natural habitats will contribute to the development of regional adaptation strategies

Dynamic conservation for migratory species

In an era of unprecedented and rapid global change, dynamic conservation strategies that tailor the delivery of habitat to when and where it is most needed can be critical for the persistence of species, especially those with diverse and dispersed habitat requirements. We demonstrate the effectiveness of such a strategy for migratory waterbirds. We analyzed citizen science and satellite data to develop predictive models of bird populations and the availability of wetlands, which we used to determine temporal and spatial gaps in habitat during a vital stage of the annual migration. We then filled those gaps using a reverse auction marketplace to incent qualifying landowners to create temporary wetlands on their properties. This approach is a cost-effective way of adaptively meeting habitat needs for migratory species, optimizes conservation outcomes relative to investment, and can be applied broadly to other conservation challenges