Projected Range Contractions of European Protected Oceanic Montane Plant Communities: Focus on Climate Change Impacts Is Essential for Their Future Conservation

Global climate is rapidly changing and while many studies have investigated the potential impacts of this on the distribution of montane plant species and communities, few have focused on those with oceanic montane affinities. In Europe, highly sensitive bryophyte species reach their optimum occurrence, highest diversity and abundance in the northwest hyperoceanic regions, while a number of montane vascular plant species occur here at the edge of their range. This study evaluates the potential impact of climate change on the distribution of these species and assesses the implications for EU Habitats Directive-protected oceanic montane plant communities. We applied an ensemble of species distribution modelling techniques, using atlas data of 30 vascular plant and bryophyte species, to calculate range changes under projected future climate change. The future effectiveness of the protected area network to conserve these species was evaluated using gap analysis. We found that the majority of these montane species are projected to lose suitable climate space, primarily at lower altitudes, or that areas of suitable climate will principally shift northwards. In particular, rare oceanic montane bryophytes have poor dispersal capacity and are likely to be especially vulnerable to contractions in their current climate space. Significantly different projected range change responses were found between 1) oceanic montane bryophytes and vascular plants; 2) species belonging to different montane plant communities; 3) species categorised according to different biomes and eastern limit classifications. The inclusion of topographical variables in addition to climate, significantly improved the statistical and spatial performance of models. The current protected area network is projected to become less effective, especially for specialised arctic-montane species, posing a challenge to conserving oceanic montane plant communities. Conservation management plans need significantly greater focus on potential climate change impacts, including models with higher-resolution species distribution and environmental data, to aid these communities’ long-term survival

Projected range contractions of european protected oceanic montane plant communities: focus on climate change impacts is essential for their future conservation

Global climate is rapidly changing and while many studies have investigated the potential impacts of this on the distribution of montane plant species and communities, few have focused on those with oceanic montane affinities. In Europe, highly sensitive bryophyte species reach their optimum occurrence, highest diversity and abundance in the northwest hyperoceanic regions, while a number of montane vascular plant species occur here at the edge of their range. This study evaluates the potential impact of climate change on the distribution of these species and assesses the implications for EU Habitats Directive-protected oceanic montane plant communities. We applied an ensemble of species distribution modelling techniques, using atlas data of 30 vascular plant and bryophyte species, to calculate range changes under projected future climate change. The future effectiveness of the protected area network to conserve these species was evaluated using gap analysis. We found that the majority of these montane species are projected to lose suitable climate space, primarily at lower altitudes, or that areas of suitable climate will principally shift northwards. In particular, rare oceanic montane bryophytes have poor dispersal capacity and are likely to be especially vulnerable to contractions in their current climate space. Significantly different projected range change responses were found between 1) oceanic montane bryophytes and vascular plants; 2) species belonging to different montane plant communities; 3) species categorised according to different biomes and eastern limit classifications. The inclusion of topographical variables in addition to climate, significantly improved the statistical and spatial performance of models. The current protected area network is projected to become less effective, especially for specialised arctic-montane species, posing a challenge to conserving oceanic montane plant communities. Conservation management plans need significantly greater focus on potential climate change impacts, including models with higher-resolution species distribution and environmental data, to aid these communities\u27 long-term survival

Proportion of overlap between current and future distribution of species groups and protected areas.

<p>(A) Grouped by plant community; a different letter signifies a significant difference between categories (Wilcoxon ranked sum; p<0.05; capitals for present, lower case for future scenarios), categories that show a significant change in overlap between current and future (Wilcoxon signed rank; p<0.01) are denoted by **. (B) Grouped by biome; letters signify significant differences between categories (Wilcoxon ranked sum; p<0.05), categories that show a significant change in overlap between current and future (Wilcoxon signed rank; p<0.01) are denoted by **.</p

Box plots of the predictive performance of species distribution models for 30 montane species, comparing models with only climate variables to those containing both climate and ecologically relevant topographic variables.

<p>The methods of evaluation used were AUC, Kappa and TSS. The difference in performance between models created using climate variables only and climate and topographic variables was significant in all cases (p<0.001).</p

Species distribution maps, showing the projected change in spatial distribution of 6 montane species under predicted climate change scenarios for 2055, representative of the two primary patterns of range change displayed by the modelled species.

<p>Species (A) <i>Anastrepta orcadensis</i>, (B) <i>Herbertus aduncus</i> subsp. <i>hutchinsiae</i> ((i) photograph of <i>H. aduncus</i> subsp. <i>hutchinsiae</i> from Co. Donegal, Ireland; (ii) distribution map) and (C) <i>Scapania ornithopodioides</i> are oceanic bryophytes, and show a potential northward shift in range. Species (D) <i>Salix herbacea</i> ((i) photograph of <i>S. herbacea</i> from Co. Donegal, Ireland; (ii) distribution map), (E) <i>Sedum rosea</i> and (F) <i>Saussurea alpina</i> ((i) photograph of <i>S. alpina</i> from Co. Kerry, Ireland; (ii) distribution map) are of arctic montane distribution, and will potentially contract in range to grid cells of higher altitude. Green grid cells  =  Gain; Blue grid cells  =  Stable; Red grid cells  =  Loss.</p

Projected percentage change in overlap with protected areas from current to future distribution, for all species modelled.

<p>Projected percentage change in overlap with protected areas from current to future distribution, for all species modelled.</p

Boxplots of the change in range (%) of species under conditions of unlimited and limited dispersal, grouped by a number of categories.

<p>(A)–(B) are grouped by plant type (bryophyte (n = 14) or vascular plant (n = 16)); (C)–(D) are grouped by community (1: montane heath (n = 10), 2: montane cliff (n = 9), 3: hepatic mat (n = 5), 4: oceanic montane bryophyte (n = 6)); (E)–(F) are grouped by biome <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095147#pone.0095147-Hill1" target="_blank">[53]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095147#pone.0095147-Hill2" target="_blank">[54]</a> (1: Arctic-montane (n = 10), 2: Boreo-arctic-montane (n = 5), 3: Boreal montane (n = 12), 4: Temperate and Southern Temperate (n = 3)); (G)–(H) are grouped by eastern limit category <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095147#pone.0095147-Hill1" target="_blank">[53]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095147#pone.0095147-Hill2" target="_blank">[54]</a> (1: hyperoceanic and oceanic (n = 8), 2: suboceanic (n = 3), 3: European, Eurosiberian and Eurasian (n = 5), 4: circumpolar (n = 14)). Range changes calculated using an ensemble of models produced by BIOMOD2.</p

Current mean, minimum, maximum and range values for climatic and topographic variables and projected climate variables for 2055.

<p>Which variable is used for oceanic bryophyte, montane heath, cliff, or all species is also indicated.</p

Maps showing the distribution of oceanic montane vegetation in Europe and Ireland.

<p>(A) Distribution range (red line) of temperate oceanic montane vegetation in Europe. (B) Main areas (red lines) where conditions are currently optimal for the occurrence of oceanic montane vegetation in Ireland, i.e. areas of altitude over 500 m, that are within the area defined as hyperoceanic by <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0095147#pone.0095147-Averis2" target="_blank">[94]</a>; shaded areas are sites designated as the Natura 2000 network of protected areas (including marine sites) on the island of Ireland.</p

A miniature world in decline: European Red List of Mosses, Liverworts and Hornworts

This publication has been prepared by IUCN (International Union for Conservation of Nature) as a deliverable of the LIFE European Red Lists project (LIFE14 PRE BE 001). A miniature world in decline: The European Red List of Mosses, Liverworts and Hornworts is, therefore, a part of a series of publications released since 2015, when the project began, that also include: • European Red List of Lycopods and Ferns, 2017 • European Red List of Saproxylic Beetles, 2018 • European Red list of Terrestrial Molluscs: slugs, snails, and semi-slugs, 2019 • European Red list of Trees, 2019 • European Red list of Selected Endemic Shrubs, 2019 Based on other European Red List assessments, 59% of freshwater molluscs, 40% of freshwater fishes, 28% of grasshoppers, crickets and bush-crickets, 23% of amphibians, 20% of reptiles, 20% of ferns and lycopods, 17% of mammals, 16% of dragonflies, 13% of birds, 9% of butterflies and bees, 8% of aquatic plants and 2% of medicinal plants are threatened at the European level (Allen et al., 2014; IUCN, 2015; Hochkirch et al., 2016; García Criado et al., 2017). Additional European Red Lists assessing a selection of species showed that 22% of terrestrial molluscs, 16% of crop wild relatives and 18% of saproxylic beetles are also threatened (Cuttelod et al., 2011; Bilz et al., 2011; Cálix et al., 2018). The findings of this work suggest that 23% of bryophytes are threatened species in Europe, representing the fifth most threatened group of plants assessed so far