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Predicting a change in the order of spring phenology in temperate forests
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The rise in spring temperatures over the past half-century has led to advances in the phenology of many nontropical plants and animals. As species and populations differ in their phenological responses to temperature, an increase in temperatures has the potential to alter timing-dependent species interactions. One species-interaction that may be affected is the competition for light in deciduous forests, where early vernal species have a narrow window of opportunity for growth before late spring species cast shade. Here we consider the Marsham phenology time series of first leafing dates of thirteen tree species and flowering dates of one ground flora species, which spans two centuries. The exceptional length of this time series permits a rare comparison of the statistical support for parameter-rich regression and mechanistic thermal sensitivity phenology models. While mechanistic models perform best in the majority of cases, both they and the regression models provide remarkably consistent insights into the relative sensitivity of each species to forcing and chilling effects. All species are sensitive to spring forcing, but we also find that vernal and
northern European species are responsive to cold temperatures in the previous autumn. Whether this sensitivity reflects a chilling requirement or a delaying of dormancy remains to be tested. We then apply the models to projected future temperature data under a fossil fuel intensive emissions scenario and predict that while some species will advance substantially others will advance by less and may even be delayed due to a rise in autumn and winter temperatures. Considering the projected responses of all fourteen species, we anticipate a change in the order of spring events, which may lead to changes in competitive advantage for light with potential implications for the composition of temperate forests.
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Too late for two degrees? Low carbon economy index 2012
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Even doubling our current rate of decarbonisation would still lead to emissions consistent with 6 degrees of
warming by the end of the century. To give ourselves a more than 50% chance of avoiding 2 degrees will
require a six-fold improvement in our rate of decarbonisation.
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Historical legacies accumulate to shape future biodiversity in an era of rapid global change
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Main conclusions : The failure to give adequate consideration to widespread cumulative time-lags often masks the full extent of biodiversity changes that have already been triggered. Effects that are particularly relevant for human livelihoods (e.g. changes in the provision of ecosystem services) may emerge with the most pronounced delay. Accordingly, the consideration of appropriate temporal scales should become a key topic in future work at the science–policy interface.
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Conserving the Stage: Climate Change and the Geophysical Underpinnings of Species Diversity
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Conservationists have proposed methods for adapting to climate change that assume species distributions are primarily explained by climate variables. The key idea is to use the understanding of species-climate relationships to map corridors and to identify regions of faunal stability or high species turnover. An alternative approach is to adopt an evolutionary timescale and ask ultimately what factors control total diversity, so that over the long run the major drivers of total species richness can be protected. Within a single climatic region, the temperate area encompassing all of the Northeastern U.S. and Maritime Canada, we hypothesized that geologic factors may take precedence over climate in explaining diversity patterns.
If geophysical diversity does drive regional diversity, then conserving geophysical settings may offer an approach to conservation that protects diversity under both current and future climates. Here we tested how well geology predicts the species diversity of 14 US states and three Canadian provinces, using a comprehensive new spatial dataset. Results of linear regressions of species diversity on all possible combinations of 23 geophysical and climatic variables indicated that four geophysical factors; the number of geological classes, latitude, elevation range and the amount of calcareous bedrock, predicted species diversity with certainty (adj. R2 = 0.94). To confirm the species-geology relationships we ran an
independent test using 18,700 location points for 885 rare species and found that 40% of the species were restricted to a single geology. Moreover, each geology class supported 5–95 endemic species and chi-square tests confirmed that calcareous bedrock and extreme elevations had significantly more rare species than expected by chance (P,0.0001), strongly corroborating the regression model. Our results suggest that protecting geophysical settings will conserve the stage for current and future biodiversity and may be a robust alternative to species-level predictions.
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Insect herbivory alters impact of atmospheric change on northern temperate forests
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Stimulation of forest productivity by elevated concentrations of CO2 is expected to partially offset continued increases in anthropogenic CO2 emissions. However, multiple factors can impair the capacity of forests to act as carbon sinks; prominent among these are tropospheric O3 and nutrient limitations (1,2). Herbivorous insects also influence carbon and nutrient dynamics in forest ecosystems, yet are often ignored in ecosystem models of forest productivity. Here we assess the effects of elevated levels of CO2 and O3 on insect-mediated canopy damage and organic matter deposition in aspen and birch stands at the Aspen FACE facility in northern Wisconsin, United States. Canopy damage was markedly higher in the elevated CO2 stands, as was the deposition of organic substrates and nitrogen. The opposite trends were apparent in the elevated O3 stands. Using a light-use efficiency model, we show that the negative impacts of herbivorous insects on net primary production more than doubled under elevated concentrations of CO2, but decreased under elevated concentrations of O3. We conclude that herbivorous insects may limit the capacity of forests to function as sinks for anthropogenic carbon emissions in a high CO2 world.
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The State of Greenhouse Gases in the Atmosphere Based on Global Observations through 2013
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The WMO Global Atmosphere Watch (GAW) coordinates observations of the most important contributors to climate change: long-lived greenhouse gases(LLGHG). In the figure, their radiative forcing (RF) is plotted along with a simple illustration of the impacts on future RF of different emission reduction scenarios. Analysis of GAW observations shows that a reduction in RF from its current level (2.92 W·m–2 in
2013)[1] requires significant reductions in anthropogenic emissions of all major greenhouse gases (GHGs).
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Protected areas in Borneo may fail to conserve tropical forest biodiversity under climate change
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Protected areas (PAs) are key for conserving rainforest species, but many PAs are becoming increasingly
isolated within agricultural landscapes, which may have detrimental consequences for the forest biota
they contain. We examined the vulnerability of PA networks to climate change by examining connectivity
of PAs along elevation gradients. We used the PA network on Borneo as a model system, and examined
changes in the spatial distribution of climate conditions in future. A large proportion of PAs will not
contain analogous climates in future (based on temperature projections for 2061–2080), potentially
requiring organisms to move to cooler PAs at higher elevation, if they are to track climate changes. For
the highest warming scenario (RCP8.5), few (11–12.5%; 27–30/240) PAs were sufficiently topographically
diverse for analogous climate conditions (present-day equivalent or cooler) to remain in situ. For the
remaining 87.5–89% (210–213/240) of PAs, which were often situated at low elevation, analogous climate
will only be available in higher elevation PAs. However, over half (60–82%) of all PAs on Borneo are too
isolated for poor dispersers (<1 km per generation) to reach cooler PAs, because there is a lack of connecting
forest habitat. Even under the lowest warming scenario (RCP2.6), analogous climate conditions will
disappear from 61% (146/240) of PAs, and a large proportion of these are too isolated for poor dispersers
to reach cooler PAs. Our results suggest that low elevation PAs are particularly vulnerable to climate
change, and management to improve linkage of PAs along elevation gradients should be a conservation
priority
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Fear of failure in conservation: The problem and potential solutions to aid conservation of extremely small populations
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The potential for extirpation of extremely small populations (ESPs) is high due to their vulnerability to
demographic and environmental stochasticity and negative impacts of human activity. We argue that
conservation actions that could aid ESPs are sometimes delayed because of a fear of failure. In human
psychology, the fear of failure is composed of several distinct cognitive elements, including ‘‘uncertainty
about the future’’ and ‘‘upsetting important others.’’ Uncertainty about the future is often driven by information obstacles in conservation: information is either not easily shared among practitioners or information is lacking. Whereas, fear of upsetting important others can be due to apprehension about angering constituents, peers, funders, and other stakeholders. We present several ways to address these fears in hopes of improving the conservation process. We describe methods for increased information sharing and improved decision-making in the face of uncertainty, and recommend a shift in focus to cooperative actions and improving methods for evaluating success. Our hope is that by tackling stumbling blocks due to the apprehension of failure, conservation and management organizations can take steps to move from fear to action.
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Reconciling nature conservation and traditional farming practices: a spatially explicit framework to assess the extent of High Nature Value farmlands in the European countryside
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Over past centuries, European landscapes have been shaped by human management. Traditional, low intensity agricultural practices, adapted to local climatic, geographic, and environmental conditions, led to a rich, diverse cultural and natural heritage, reflected in a wide range of rural landscapes, most of which were preserved until the advent of industrialized agriculture (Bignal & McCracken 2000; Paracchini et al. 2010; Oppermann et al. 2012). Agricultural landscapes currently account for half of Europe’s territory (Overmars et al. 2013), with ca. 50% of all species relying on agricultural habitats at least to some extent (Kristensen 2003; Moreira et al. 2005; Halada et al. 2011). Due to their acknowledged role in the maintenance of high levels of biodiversity, low-intensity farming systems have been highlighted as critical to nature conservation and protection of the rural environment (Beaufoy et al. 1994; Paracchini et al. 2010; Halada et al.2011; Egan & Mortensen 2012).
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Invited Review: Quantifying surface albedo and other direct biogeophysical climate forcings of forestry activities
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By altering fluxes of heat, momentum, and moisture exchanges between the land surface and atmosphere, forestry and other land-use activities affect climate. Although long recognized scientifically as being important, these so-called biogeophysical forcings are rarely included in climate policies for forestry and other land management projects due to the many challenges associated with their quantification. Here, we review the scientific literature in the fields of atmospheric science and terrestrial ecology in light of three main objectives: (i) to elucidate the challenges associated with quantifying biogeophysical climate forcings connected to land use and land management, with a focus on the forestry sector; (ii) to identify and describe scientific approaches and/or metrics facilitating the quantification and interpretation of direct biogeophysical climate forcings; and (iii) to identify and recommend research priorities that can help overcome the challenges of their attribution to specific land-use activities, bridging the knowledge gap between the climate modeling, forest ecology, and resource management communities. We find that ignoring surface
biogeophysics may mislead climate mitigation policies, yet existing metrics are unlikely to be sufficient. Successful metrics ought to (i) include both radiative and nonradiative climate forcings; (ii) reconcile disparities between biogeophysical and biogeochemical forcings, and (iii) acknowledge trade-offs between global and local climate benefits. We call for more coordinated research among terrestrial ecologists, resource managers, and coupled climate modelers to harmonize datasets, refine analytical techniques, and corroborate and validate metrics that are more amenable to analyses at the scale of an individual site or region.
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