Unique genetic variation at a species' rear edge is under threat from global climate change

Global climate change is having a significant effect on the distributions of a wide variety of species, causing both range shifts and population extinctions. To date, however, no consensus has emerged on how these processes will affect the range-wide genetic diversity of impacted species. It has been suggested that species that recolonized from low-latitude refugia might harbour high levels of genetic variation in rear-edge populations, and that loss of these populations could cause a disproportionately large reduction in overall genetic diversity in such taxa. In the present study, we have examined the distribution of genetic diversity across the range of the seaweed Chondrus crispus, a species that has exhibited a northward shift in its southern limit in Europe over the last 40 years. Analysis of 19 populations from both sides of the North Atlantic using mitochondrial single nucleotide polymorphisms (SNPs), sequence data from two singlecopy nuclear regions and allelic variation at eight microsatellite loci revealed unique genetic variation for all marker classes in the rear-edge populations in Iberia, but not in the rear-edge populations in North America. Palaeodistribution modelling and statistical testing of alternative phylogeographic scenarios indicate that the unique genetic diversity in Iberian populations is a result not only of persistence in the region during the last glacial maximum, but also because this refugium did not contribute substantially to the recolonization of Europe after the retreat of the ice. Consequently, loss of these rear-edge populations as a result of ongoing climate change will have a major effect on the overall genetic diversity of the species, particularly in Europe, and this could compromise the adaptive potential of the species as a whole in the face of future global warming.

Northern Ireland's Consent to the Climate Change Act 2008: An Illusion?

This is the first in a two-part analysis of Northern Ireland’s engagement with the climate governance regime created by the UK Climate Change Act 2008. It contends that UK devolution has shaped this national regime and may itself be shaped by the national low carbon transition, particularly in the case of the UK’s most devolved region. In essence, while Northern Ireland’s consent to the application of the Act appeared to represent a long-term commitment to share power in the interests of present and future generations and thus to devolution itself, this first article argues that it was also potentially illusory. The second article argues that making an effective commitment to climate governance will require its devolved administration to allow constitutional arrangements designed for conflict resolution to mature. Failure to do so will have important implications for the UK’s putative ‘national’ low carbon transition and the longer term viability of devolution in the region.

Climate change, Hans Jonas and indirect investors

This article considers how corporate behaviour in relation to climate change might be reconfigured and the role that indirect investors might play in this reconfiguring. The article suggests that the consequences of climate change are serious enough that indirect investors might be prevailed upon, using a model of behaviour suggested by the work of Hans Jonas, to pressure institutional investors into demanding changes in corporate policy towards climate change. Jonas' work represents a plea for the recognition and acceptance of responsibility in the face of nature's vulnerability and humanity's power over technology. The article suggests that this ethic can be operationalised in relation to corporate governance by building on the changes in the pattern of investment holdings that have taken place in large public companies in the preceding two decades or so. The idea is to appeal to individuals who may perceive themselves as currently being outsiders – or at least only distant stakeholders in relation to the corporation – to realise the responsibility vested in them as beneficiaries through their interest in pension funds, life assurance policies, annuities and other arm's-length financial arrangements with corporations. The hope is that these individuals may, through the influence of a model of responsibility, become active investors and beneficiaries interested in corporate practices that impact on climate change and, encourage others to do likewise.

Climate change and the cost of conserving species in Madagascar

We examined the cost of conserving species as climate changes using Madagascar as an example. We used a Maxent species distribution model to predict the ranges of 74 plant species endemic to the forests of Madagascar from 2000-2080 in three climate scenarios. We set a conservation target of achieving 10,000 hectares of forest cover for each species, and calculated the cost of achieving this target under each climate scenario. We interviewed natural forest restoration project managers and conducted a literature review to obtain the net present cost per hectare of management actions to maintain or establish forest cover. For each species we added hectares of land from lowest to highest cost per additional year of forest cover until the conservation target was achieved throughout the time period. Climate change was predicted to reduce the size of species’ ranges, the overlap between species’ ranges and existing or planned protected areas, and the overlap between species’ ranges and existing forest. As a result, climate change increased the cost of achieving the conservation target by necessitating successively more costly management actions: additional management within existing protected areas (US$0-60/ha), avoidance of forest degradation (loss of biomass) in community-managed areas ($160-576/ha), avoidance of deforestation in unprotected areas ($252-1069/ha), and establishment of forest on non-forested land within protected areas ($802-2710/ha), in community-managed areas ($962-3226/ha), and in unprotected areas ($1054-3719/ha). Our results suggest that though forest restoration may be required for the conservation of some species as climate changes, it is more cost-effective to maintain existing forest wherever possible.