Vulnerability of mires under climate change: implications for nature conservation and climate change adaptation

Wetlands in general and mires in particular belong to the most important terrestrial carbon stocks globally. Mires (i.e. bogs, transition bogs and fens) are assumed to be especially vulnerable to climate change because they depend on specific, namely cool and humid, climatic conditions. In this paper, we use distribution data of the nine mire types to be found in Austria and habitat distribution models for four IPCC scenarios to evaluate climate change induced risks for mire ecosystems within the 21st century. We found that climatic factors substantially contribute to explain the current distribution of all nine Austrian mire ecosystem types. Summer temperature proved to be the most important predictor for the majority of mire ecosystems. Precipitation—mostly spring and summer precipitation sums—was influential for some mire ecosystem types which depend partly or entirely on ground water supply (e.g. fens). We found severe climate change induced risks for all mire ecosystems, with rain-fed bog ecosystems being most threatened. Differences between scenarios are moderate for the mid-21st century, but become more pronounced towards the end of the 21st century, with near total loss of climate space projected for some ecosystem types (bogs, quagmires) under severe climate change. Our results imply that even under minimum expected, i.e. inevitable climate change, climatic risks for mires in Austria will be considerable. Nevertheless, the pronounced differences in projected habitat loss between moderate and severe climate change scenarios indicate that limiting future warming will likely contribute to enhance long-term survival of mire ecosystems, and to reduce future greenhouse gas emissions from decomposing peat. Effectively stopping and reversing the deterioration of mire ecosystems caused by conventional threats can be regarded as a contribution to climate change mitigation. Because hydrologically intact mires are more resilient to climatic changes, this would also maintain the nature conservation value of mires, and help to reduce the severe climatic risks to which most Austrian mire ecosystems may be exposed in the 2nd half of the 21st century according to IPCC scenarios.     

Palms tracking climate change

Aim  Many species are currently expanding their ranges in response to climate change, but the mechanisms underlying these range expansions are in many cases poorly understood. In this paper we explore potential climatic factors governing the recent establishment of new palm populations far to the north of any other viable palm population in the world.
Location  Southern Switzerland, Europe, Asia and the world.
Methods  We identified ecological threshold values for the target species, Trachycarpus fortunei , based on gridded climate data, altitude and distributional records from the native range and applied them to the introduced range using local field monitoring and measured meteorological data as well as a bioclimatic model.
Results  We identified a strong relationship between minimum winter temperatures, influenced by growing season length and the distribution of the palm in its native range. Recent climate change strongly coincides with the palm's recent spread into southern Switzerland, which is in concert with the expansion of the global range of palms across various continents.
Main conclusions  Our results strongly suggest that the expansion of palms into (semi-)natural forests is driven by changes in winter temperature and growing season length and not by delayed population expansion. This implies that this rapid expansion is likely to continue in the future under a warming climate. Palms in general, and T. fortunei in particular, are significant bioindicators across continents for present-day climate change and reflect a global signal towards warmer conditions.     

European Policy Review: Biodiversity and climate change

Climate change and its impacts on biodiversity have gained much political and scientific interest over the past decade. In order for the right policy measures to be taken on adaptation and mitigation, research and stakeholder involvement has a strong role to play to support decision makers. This paper provides an overview of recent developments and research needs in Europe.     

Plants and climate change: complexities and surprises

Background Anthropogenic climate change (ACC) will influence all aspects of plant biology over coming decades. Many changes in wild species have already been well-documented as a result of increased atmospheric CO₂ concentrations, warming climate and changing precipitation regimes. A wealth of available data has allowed the use of meta-analyses to examine plant–climate interactions on more sophisticated levels than before. These analyses have revealed major differences in plant response among groups, e.g. with respect to functional traits, taxonomy, life-history and provenance. Interestingly, these meta-analyses have also exposed unexpected mismatches between theory, experimental, and observational studies.Scope We reviewed the literature on species’ responses to ACC, finding ∼42 % of 4000 species studied globally are plants (primarily terrestrial). We review impacts on phenology, distributions, ecophysiology, regeneration biology, plant–plant and plant–herbivore interactions, and the roles of plasticity and evolution. We focused on apparent deviations from expectation, and highlighted cases where more sophisticated analyses revealed that unexpected changes were, in fact, responses to ACC.Conclusions We found that conventionally expected responses are generally well-understood, and that it is the aberrant responses that are now yielding greater insight into current and possible future impacts of ACC. We argue that inconclusive, unexpected, or counter-intuitive results should be embraced in order to understand apparent disconnects between theory, prediction, and observation. We highlight prime examples from the collection of papers in this Special Issue, as well as general literature. We found use of plant functional groupings/traits had mixed success, but that some underutilized approaches, such as Grime''s C/S/R strategies, when incorporated, have improved understanding of observed responses. Despite inherent difficulties, we highlight the need for ecologists to conduct community-level experiments in systems that replicate multiple aspects of ACC. Specifically, we call for development of coordinating experiments across networks of field sites, both natural and man-made.     

Horizontal cliffs: mountaintop mining and climate change

Poleward and upward shifts in ranges in plant and animal species are amongst the most confident impacts of climate change on terrestrial ecosystems. While mountain tops have long been recognised as an important limit in this regard, the implications of the practice of mountaintop removal mining, i.e., acting counter to the upward shift of species, have yet to be considered. In regions where climate warming and mountaintop mining occur together, species face increased risk of range contraction and local extinction.     

Ecology: pollinator-plant synchrony tested by climate change

Flowering plants could lose their pollination service if climate warming potentially uncouples timing of flowering from pollinator availability. Recent evidence might suggest this effect may be less than feared.     

Tropical reforestation and climate change: beyond carbon

Tropical reforestation (TR) has been highlighted as an important intervention for climate change mitigation because of its carbon storage potential. TR can also play other frequently overlooked, but significant, roles in helping society and ecosystems adapt to climate variability and change. For example, reforestation can ameliorate climate‐associated impacts of altered hydrological cycles in watersheds, protect coastal areas from increased storms, and provide habitat to reduce the probability of species' extinctions under a changing climate. Consequently, reforestation should be managed with both adaptation and mitigation objectives in mind, so as to maximize synergies among these diverse roles, and to avoid trade‐offs in which the achievement of one goal is detrimental to another. Management of increased forest cover must also incorporate measures for reducing the direct and indirect impacts of changing climate on reforestation itself. Here we advocate a focus on “climate‐smart reforestation,” defined as reforesting for climate change mitigation and adaptation, while ensuring that the direct and indirect impacts of climate change on reforestation are anticipated and minimized.