Anouschka R. Hof

Future Climate Change Will Favour Non-Specialist Mammals in the (Sub)Arctics

Arctic and subarctic (i.e., [sub]arctic) ecosystems are predicted to be particularly susceptible to climate change. The area of tundra is expected to decrease and temperate climates will extend further north, affecting species inhabiting northern environments. Consequently, species at high latitudes should be especially susceptible to climate change, likely experiencing significant range contractions. Contrary to these expectations, our modelling of species distributions suggests that predicted climate change up to 2080 will favour most mammals presently inhabiting (sub)arctic Europe. Assuming full dispersal ability, most species will benefit from climate change, except for a few cold-climate specialists. However, most resident species will contract their ranges if they are not able to track their climatic niches, but no species is predicted to go extinct. If climate would change far beyond current predictions, however, species might disappear. The reason for the relative stability of mammalian presence might be that arctic regions have experienced large climatic shifts in the past, filtering out sensitive and range-restricted taxa. We also provide evidence that for most (sub)arctic mammals it is not climate change per se that will threaten them, but possible constraints on their dispersal ability and changes in community composition. Such impacts of future changes in species communities should receive more attention in literature.

Predicting the fate of biodiversity using species' distribution models: enhancing model comparability and repeatability.

Species distribution modeling (SDM) is an increasingly important tool to predict the geographic distribution of species. Even though many problems associated with this method have been highlighted and solutions have been proposed, little has been done to increase comparability among studies. We reviewed recent publications applying SDMs and found that seventy nine percent failed to report methods that ensure comparability among studies, such as disclosing the maximum probability range produced by the models and reporting on the number of species occurrences used. We modeled six species of Falco from northern Europe and demonstrate that model results are altered by (1) spatial bias in species’ occurrence data, (2) differences in the geographic extent of the environmental data, and (3) the effects of transformation of model output to presence/absence data when applying thresholds. Depending on the modeling decisions, forecasts of the future geographic distribution of Falco ranged from range contraction in 80% of the species to no net loss in any species, with the best model predicting no net loss of habitat in Northern Europe. The fact that predictions of range changes in response to climate change in published studies may be influenced by decisions in the modeling process seriously hampers the possibility of making sound management recommendations. Thus, each of the decisions made in generating SDMs should be reported and evaluated to ensure conclusions and policies are based on the biology and ecology of the species being modeled.

Food or fear? : Predation risk mediates edge refuging in an insectivorous mammal

Understanding space use by animals plays a key role in a wide array of behavioural and ecological fields of study. An insight into how and why species use the space available to them may aid their conservation. The West European hedgehog, Erinaceus europaeus, a species in decline in part of its range, is relatively mobile and adapted to a wide range of habitat types. However, it is frequently associated with edge habitats. This edge-refuging behaviour is not well understood and may be the result of fear of predators, food availability or other factors. We used radiotelemetry to investigate the movement of hedgehogs in comparable landscapes with high and low predator (badgers, Meles meles) abundance. Simultaneously, food availability was assessed in both landscapes. Our results suggest that agricultural habitats may be ‘landscapes of fear’ for hedgehogs in the presence of a high number of predators. On agricultural fields, hedgehogs were on average situated closer to edge cover in areas with predators present. It is thus likely to be beneficial for the conservation of hedgehogs in areas with a high number of predators to increase the complexity of the habitat structure by, among other measures, establishing more and denser hedgerows in rural areas. Our results suggest that enhancing the complexity of the habitat structure might lessen the effects of fear. Additionally, our results emphasize the importance of integrating data on predator abundance and food availability in studies that focus on habitat selection behaviour and species conservation.

The potential effect of climate change on the geographical distribution of insect pest species in the Swedish boreal forest

ABSTRACT With the expected rising temperatures, outbreaks of insect pests may be more frequent, which can have large consequences on forest ecosystems and may therefore negatively affect the forestry sector. In order to be better able to predict where, but not if, outbreaks may occur in future we investigated the potential future (2070) geographical distribution of 30 prospective insect pest species (Coleoptera and Lepidoptera) by applying species distribution modelling. We also assessed the geographical extent to which the boreal forest in Sweden may be affected. We found that numerous species may experience large increases in their potential distribution in future, which may result in outbreaks in “new” areas. It is therefore likely that more trees will be infested by pests in future, which may have large implications for the Swedish forestry sector.

Factors affecting hedgehog presence on farmland as assessed by a questionnaire survey

The West European hedgehog, (Erinaceus europaeus, Linnaeus 1758) is widely distributed in Western Europe. However, there is evidence of decline in parts of its range. Changes in agricultural management have partly been the driving force behind the loss of species diversity and abundance, and it has been argued that these changes play a role in the decline of hedgehogs as well. We used a questionnaire to investigate the current distribution of hedgehogs on farmland throughout Great Britain with a focus on different environmental zones. Additionally, we identified environmental correlates that related to the distribution of hedgehogs with the aim to get a better understanding of what is needed to design appropriate strategies targeted at the conservation of hedgehogs. Our study illustrates that, although the impact of several variables was rather ambiguous, displaying positive effects in some environmental zones and negative effects in other, major roads and Eurasian badgers (Meles meles, Linnaeus 1758) can have large scale negative effects on hedgehogs. Farm management related factors did not show a consistent impact on hedgehog presence. Conservation strategies should therefore be aimed at lessening the impacts of major roads and badger presence. Wildlife passages, for instance, may provide hedgehogs safe passages across roads. Additionally, increasing the habitat complexity in order to reduce the impact of predators can be beneficial for prey species, such as hedgehogs, and should be considered as a conservation strategy for them.

Alien species in a warming climate: a case study of the nutcracker and stone pines

Species are predicted to shift their geographic range with climate change, which increases the need for good conservation planning and management practices. Not only may climate change increase the number of invasive species in parts of the world, it may also lead to some species becoming invasive under new, more preferable, climatic conditions. This study investigates whether climate change may enhance the spread of alien species by another alien species. I use the interaction between the alien slender-billed nutcracker and alien, potentially invasive, stone pines as a case-study and specifically aim to quantify to which extent the potential spread of stone pine species in Sweden in a warming climate is augmented by its dispersal agent: the slender-billed nutcracker. I found that accounting for the future climatic niche of the slender-billed nutcracker, and therefore for its potential presence, significantly augmented the increase of the predicted future range of the stone pines under climate change. This result does not only stress the importance of accounting for species interactions when assessing the impact of climate change on species’ future geographic ranges, it also stresses the need for nature conservationists and managers to incorporate species interactions and climate change when designing appropriate plans with regard to invasive species. Although the implications of the predicted future spread of the slender-billed nutcracker might be limited, since the very similar thick-billed nutcracker is native to Sweden, the effects of the stone pines should not be neglected. They are currently classified as potentially invasive in parts of the Nordic region.

Future of biodiversity in the Barents Region

Climate change may affect biodiversity to a large extent. Its effects have already caused shifts in species distributions and even species extinctions. Since especially high latitude regions are ex ...

Paleodistribution modeling suggests glacial refugia in Scandinavia and out‐of‐Tibet range expansion of the Arctic fox

Abstract Quaternary glacial cycles have shaped the geographic distributions and evolution of numerous species in the Arctic. Ancient DNA suggests that the Arctic fox went extinct in Europe at the end of the Pleistocene and that Scandinavia was subsequently recolonized from Siberia, indicating inability to track its habitat through space as climate changed. Using ecological niche modeling, we found that climatically suitable conditions for Arctic fox were found in Scandinavia both during the last glacial maximum (LGM) and the mid‐Holocene. Our results are supported by fossil occurrences from the last glacial. Furthermore, the model projection for the LGM, validated with fossil records, suggested an approximate distance of 2000 km between suitable Arctic conditions and the Tibetan Plateau well within the dispersal distance of the species, supporting the recently proposed hypothesis of range expansion from an origin on the Tibetan Plateau to the rest of Eurasia. The fact that the Arctic fox disappeared from Scandinavia despite suitable conditions suggests that extant populations may be more sensitive to climate change than previously thought.

Future breeding and foraging sites of a southern edge population of the locally endangered Black Guillemot Cepphus grylle

ABSTRACT Capsule: One of the southernmost populations of the Black Guillemot Cepphus grylle is currently endangered, and the risk may be exacerbated by climate change. Aims: We evaluated the future vulnerability of the Black Guillemot by predicting the impact of climate change on the geographic distribution of its breeding and foraging range in the Baltic Sea. Methods: We used MaxEnt, a species distribution modelling technique, to predict the current and future breeding grounds and foraging sites. Results: We found that although the foraging range is expected to increase in the southern Baltic Sea in future, these areas will no longer be suitable as breeding grounds due to a changing climate, creating a spatial mismatch. Conclusion: Our predictions indicate where threats to the species may be most severe and can be used to guide conservation planning. We advocate conservation measures which integrate potential future threats and focus on breeding sites across the current and future potential geographic range of the Black Guillemot.

Not erroneous but cautious conclusions about the potential effect of climate change on the geographical distribution of insect pest species in the Swedish boreal forest. Response to Björklund et al. (2015)

ABSTRACT We argue that the conclusions drawn from the paper “The potential effect of climate change on the geographical distribution of insect pest species in the Swedish boreal forest”, published in the Scandinavian Journal of Forest Research were not erroneous as stated by a letter published in the same journal by Björklund et al. (2015. Erroneous conclusions about current geographical distribution and future expansion of forest insects in Northern Sweden: Comments on Hof and Svahlin (2015). Scand. J. Forest Res)”, but cautious. We regret possible underestimations caused by lack of occurrence records for some species for some areas. However, basing predictions of the impact of future climate change on the distribution of species on current range maps likely leads to grave overestimations of future range predictions since current range maps assume species are homogenously distributed throughout the landscape, which is often not the case. We argue that underestimating the distribution range of pest species rather than overestimating their distribution pinpoints areas that may need extra attention in future better, and therefore chose to be cautious rather than bold. We further like to stress that one should always be aware of possible insect outbreaks throughout the region, not only because predictions may underestimate the future distribution of species but also since the location and likelihood of insect pest outbreaks is not only determined by climatic factors.