• Energy Research

Madagascar’s recently elected president ran on a platform of improving the economy and raising people out of poverty. We suggest that addressing the precipitous decline of biodiversity will help to deliver this commitment, and we lay out ways in which President Rajoelina could firmly put the country on a trajectory towards sustainable growth.

Climate change is affecting biodiversity worldwide, but conservation responses are constrained by considerable uncertainty regarding the magnitude, rate and ecological consequences of expected climate change. Here we propose a framework to account for several sources of uncertainty in conservation prioritization. Within this framework we account for uncertainties arising from (i) species distributions that shift following climate change, (ii) basic connectivity requirements of species, (iii) alternative climate change scenarios and their impacts, (iv) in the modelling of species distributions, and (v) different levels of confidence about present and future. When future impacts of climate change are uncertain, robustness of decision-making can be improved by quantifying the risks and trade-offs associated with climate scenarios. Sensible prioritization that accounts simultaneously for the present and potential future distributions of species is achievable without overly jeopardising present-day conservation values. Doing so requires systematic treatment of uncertainties and testing of the sensitivity of results to assumptions about climate. We illustrate the proposed framework by identifying priority areas for amphibians and reptiles in Europe.

The role of bioenergy in climate change mitigation is a topic of heated debate, as the demand for land may result in social and ecological conflicts. Biodiversity impacts are a key controversy, given that biodiversity conservation is a globally agreed goal under pressure due to both climate change and land use. Impact assessment of bioenergy in various socio-economic and policy scenarios is a crucial basis for planning sound climate mitigation policy. Empirical studies have identified positive and negative local impacts of different bioenergy types on biodiversity, but ignored indirect impacts caused by displacement of other human activities. Integrated assessment models (IAMs) provide land-use scenarios based on socio-economic and policy storylines. Global scenarios capture both direct and indirect land-use change, and are therefore an appealing tool for assessing the impacts of bioenergy on biodiversity. However, IAMs have been originally designed to address questions of a different nature. Here, we illustrate the properties of IAMs from the biodiversity conservation perspective and discuss the set of questions they could answer. We find IAMs are a useful starting point for more detailed regional planning and assessment. However, they have important limitations that should not be overlooked. Global scenarios may not capture all impacts, such as changes in forest habitat quality or small-scale landscape structure, identified as key factors in empirical studies. We recommend increasing spatial accuracy of IAMs through region-specific, complementary modelling, including climate change into predictive assessments, and considering future biodiversity conservation needs in assessments of impacts and sustainable potentials of bioenergy.

Stochastic upwelling of seawater in the Baltic Sea from the deep, anoxic bottoms may bring low-pH water rich in CO2 close to the surface. Such events may become more frequent with climate change and ongoing ocean acidification (OA). Photoautotrophs, such as macroalgae, which are important foundation species, have been proposed to benefit from increased carbon availability due to reduced energetic cost in carbon acquisition. However, the exact effects of CO2 fertilization may depend on the ambient light environment, as photosynthesis rates depend on available irradiance. In this experimental study, interacting effects of CO2 addition and irradiance on the habitat-forming macroalga Fucus vesiculosus were investigated during two seasons ��� winter and summer ��� in the northern Baltic Sea. Growth rates remained unaffected by CO2 or irradiance during both seasons, suggesting that direct effects of elevated CO2 on mature F. vesiculosus are small. Increases in CO2 affected algal elemental ratios by increasing carbon and decreasing nitrogen content, with resulting changes in the C:N ratio, but only in winter. In summer, chlorophyll a content increased under low irradiance. Increases in CO2 caused a decline in light-harvesting efficiency (decrease in Fv/Fm and ��) under high irradiance in summer, and conversely increased �� under low irradiance. High irradiance caused increases in the maximum relative electron transport rate (rETRmax) in summer, but not in winter. Differences between winter and summer indicate that F. vesiculosus responses to CO2 and irradiance are season-specific. Increases in carbon content during winter could indicate slightly positive effects of CO2 addition in the long run if the extra carbon gained may be capitalized in growth. The results of this study suggest that increases in CO2, either through upwelling or OA, may have positive effects on F. vesiculosus, but these effects are probably small.

AbstractAimBioclimatic envelope models are widely used to describe changes in climatically suitable areas for species under future climate scenarios. Climate change metrics are applied independently of species data to characterize the spatio‐temporal dynamics of climate, and have also been used as indicators of the exposure of species to climate change. Here, we investigate whether these two approaches provide qualitatively similar indications about where biodiversity is potentially most exposed to climate change.LocationSub‐Saharan Africa.MethodsWe compared a range of climate change metrics for sub‐Saharan Africa with ensembles of bioclimatic envelope models for 2723 species of amphibians, snakes, mammals and birds. For each taxonomic group, we performed three comparisons between the two approaches: (1) is projected change in local climatic suitability (models) greater in grid cells with larger temporal differences in local climate (metrics); (2) are projected losses or gains of climatically suitable areas (models) greater for species in grid cells with climates that are projected to be less or more available in the future, respectively (metrics); and (3) are projected shifts in the position of climatically suitable areas (models) greater for species in grid cells with climates projected to move farther in space (metrics)?ResultsThe changes in climatic suitability projected by the bioclimatic envelope models covaried with the climatic changes measured with the metrics. Agreement between the two approaches was found for all taxonomic groups, although it was stronger for species with a narrower climatic envelope breadth.Main conclusionsFor sub‐Saharan African vertebrates, projected patterns of exposure to climate change given by climate change metrics alone were qualitatively comparable to bioclimatic model projections of changes in areas of suitable climate for species. Assessments based on climate change metrics can thus be useful for making first‐cut inferences about the potential effects of climate change on regions with poorly known biodiversity.

AbstractAlthough many studies predict extensive future biodiversity loss and redistribution in the terrestrial realm, future changes in marine biodiversity remain relatively unexplored. In this work, we model global shifts in one of the most important marine functional groups—ecosystem-structuring macrophytes—and predict substantial end-of-century change. By modelling the future distribution of 207 brown macroalgae and seagrass species at high temporal and spatial resolution under different climate-change projections, we estimate that by 2100, local macrophyte diversity will decline by 3–4% on average, with 17 to 22% of localities losing at least 10% of their macrophyte species. The current range of macrophytes will be eroded by 5–6%, and highly suitable macrophyte habitat will be substantially reduced globally (78–96%). Global macrophyte habitat will shift among marine regions, with a high potential for expansion in polar regions.