Article

Projected distributions of novel and disappearing climates by 2100 AD

Department of Geography, 550 North Park Street, University of Wisconsin, Madison, WI 53706, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.81). 05/2007; 104(14):5738-42. DOI: 10.1073/pnas.0606292104
Source: PubMed

ABSTRACT Key risks associated with projected climate trends for the 21st century include the prospects of future climate states with no current analog and the disappearance of some extant climates. Because climate is a primary control on species distributions and ecosystem processes, novel 21st-century climates may promote formation of novel species associations and other ecological surprises, whereas the disappearance of some extant climates increases risk of extinction for species with narrow geographic or climatic distributions and disruption of existing communities. Here we analyze multimodel ensembles for the A2 and B1 emission scenarios produced for the fourth assessment report of the Intergovernmental Panel on Climate Change, with the goal of identifying regions projected to experience (i) high magnitudes of local climate change, (ii) development of novel 21st-century climates, and/or (iii) the disappearance of extant climates. Novel climates are projected to develop primarily in the tropics and subtropics, whereas disappearing climates are concentrated in tropical montane regions and the poleward portions of continents. Under the high-end A2 scenario, 12-39% and 10-48% of the Earth's terrestrial surface may respectively experience novel and disappearing climates by 2100 AD. Corresponding projections for the low-end B1 scenario are 4-20% and 4-20%. Dispersal limitations increase the risk that species will experience the loss of extant climates or the occurrence of novel climates. There is a close correspondence between regions with globally disappearing climates and previously identified biodiversity hotspots; for these regions, standard conservation solutions (e.g., assisted migration and networked reserves) may be insufficient to preserve biodiversity.

4 Followers
 · 
126 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Assisted migration (AM) is increasingly proposed to limit the impacts of climate change on vulnerable plant and animal populations. However, interpretations of AM as a purely precautionary action along with multiple definitions have hampered the development of precise policy frameworks. Here, our main objective is to identify what type of policy tools are needed for implementing AM programs as part of broader environmental policies. First, we argue that policy frameworks for translocations of endangered species that are subject to climatic stress are fundamentally different from translocations to reinforce climatically exposed ecosystems because the former are risky and stranded in strict regulations while the latter are open to merges with general landscape management. AM implementation can be based on a series of phases where policies should provide appropriate grounds closely related to extant environmental principles. During a “Triggering phase”, AM is clearly a prevention approach as considered by the Rio Declaration, if unambiguously based on evidence that population decline is mainly caused by climate change. During an “Operational phase”, we suggest that policies should enforce experimentation and be explicit on transparent coordination approaches for collating all available knowledge and ensure multi-actor participation prior to any large scale AM program. In addition, precautionary approaches are needed to minimize risks of translocation failures (maladaptation) that can be reduced through redundancy of multiple target sites. Lastly, monitoring and learning policies during an “Adaptive phase” would promote using flexible management rules to react and adjust to any early alerts, positive or negative, as hybridization with local individuals may represent an evolutionary chance. Our analysis of study cases indicates that except for two programs of productive forests in Canada, current AM programs are predominantly small-scale, experimental and applied to endangered species isolated from general environmental management. As the effects of climate change accumulate, policies could include AM as part of larger environmental programs like habitat restoration with common species seeking to provide stable ecosystems in the future.
    Environmental Science & Policy 08/2015; 51. DOI:10.1016/j.envsci.2015.04.005 · 3.51 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Climate change is strong in the Amazon basin. Climate models consistently predict widespread warmer and drier conditions by the end of the 21st century. As a consequence, water stress will increase throughout the region. We here review current understanding of the impact of climate change on forests' distribution patterns, species diversity and ecosystem functioning of lowland rainforests in the Amazon basin. We reviewed 192 studies that provide empirical evidence, historical information and theoretical models. Over millions of years rainforests expansions and contractions have been accompanied by changes in the diversity and productivity of forests. In the future, drought will produce forest contractions along the forest edges and the savanna ecotone, causing an extensive savannization, particularly in the east. In terms of diversity, warming will reduce plant species survival by decreasing their productivity, but extinctions may also occur as a result of vegetation disequilibrium, as many plants, dispersal and pollinator species will fail to track changing climate; mild drought kills understory trees and severe drought may eliminate canopy trees as well. Severe droughts will thus produce directional changes in species composition, although these shifts may vary among forests on different soil types. In terms of ecosystem functioning, droughts will reduce root growth and standing biomass and may shift the Amazonian forest from being CO2 sinks to become CO2 sources. Physiological and ecological responses to warming and the feedback between vegetation and climate are still not completely understood. In particular, experimental assays that allow direct conclusions on the response of Amazonian plants to the predicted climatic conditions are needed. Such studies could make possible more reliable estimates of future climatic and vegetation responses.
    The Botanical Review 02/2015; 81(1). DOI:10.1007/s12229-014-9149-8 · 2.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Assessing the future of biodiversity under changing climates is plagued by uncertainty. Drawing on data for sub-Saharan African vertebrates, I focus on some of the major sources of uncertainty surrounding bioclimatic envelope model projections and on possible ways to address them. I examine the uncertainty arising from alternative climate projections and model algorithms and I summarise it through consensus building. To examine ecological uncertainty, I present a framework for teasing apart projected gains, losses, and fragmentation of climatically suitable areas; each of these threats and opportunities can be examined with reference to relevant response-mediating biological traits, such as the species' climatic tolerance, reproductive output,

Preview

Download
8 Downloads
Available from