-
A long-term perspective on a modern drought in the American Southeast
-
The depth of the 2006–9 drought in the humid, southeastern US left several metropolitan areas
with only a 60–120 day water supply. To put the region’s recent drought variability in a long-term
perspective, a dense and diverse tree-ring network—including the first records throughout the
Apalachicola–Chattahoochee–Flint river basin—is used to reconstruct drought from 1665 to 2010
CE. The network accounts for up to 58.1% of the annual variance in warm-season drought during
the 20th century and captures wet eras during the middle to late 20th century. The reconstruction
shows that the recent droughts are not unprecedented over the last 346 years. Indeed, droughts of
extended duration occurred more frequently between 1696 and 1820. Our results indicate that the
era in which local and state water supply decisions were developed and the period of instrumental
data upon which it is based are amongst the wettest since at least 1665. Given continued growth
and subsequent industrial, agricultural and metropolitan demand throughout the southeast, insights
from paleohydroclimate records suggest that the threat of water-related conflict in the region has
potential to grow more intense in the decades to come.
Located in
Resources
/
Climate Science Documents
-
Scenarios of future land use change around United States’ protected areas
-
Land use change around protected areas can diminish their conservation value, making it important to
predict future land use changes nearby. Our goal was to evaluate future land use changes around protected
areas of different types in the United States under different socioeconomic scenarios. We analyzed
econometric-based projections of future land use change to capture changes around 1260 protected
areas, including National Forests, Parks, Refuges, and Wilderness Areas, from 2001 to 2051, under different
land use policies and crop prices. Our results showed that urban expansion around protected areas
will continue to be a major threat, and expand by 67% under business-as-usual conditions.
Concomitantly, a substantial number of protected areas will lose natural vegetation in their surroundings.
National land-use policies or changes in crop prices are not likely to affect the overall pattern of land use,
but can have effects in certain regions. Discouraging urbanization through zoning, for example, can
reduce future urban pressures around National Forests and Refuges in the East, while the implementation
of an afforestation policy can increase the amount of natural vegetation around some Refuges throughout
the U.S. On the other hand, increases in crop prices can increase crop/pasture cover around some protected
areas, and limit the potential recovery of natural vegetation. Overall, our results highlight that future
land-use change around protected areas is likely to be substantial but variable among regions and
protected area types. Safeguarding the conservation value of protected areas may require serious consideration of threats and opportunities arising from future land use.
Located in
Resources
/
Climate Science Documents
-
Scaling up from gardens: biodiversity conservation in urban environments
-
As urbanisation increases globally and the natural environment becomes increasingly fragmented, the
importance of urban green spaces for biodiversity conservation grows. In many countries, private gardens area major component of urban green space and can provideconsiderable biodiversity benefits. Gardens and
adjacent habitats form interconnected networks and a landscape ecology framework is necessary to understand the relationship between the spatial configuration of garden patches and their constituent biodiversity. A scale-dependent tension is apparent in garden management, whereby the individual garden is much smaller than the unit of management needed to retain viable populations. To overcome this, here we suggest mechanisms for encouraging ‘wildlife-friendly’ management of collections of gardens across scales from the neighbourhood to the city.
Located in
Resources
/
Climate Science Documents
-
A global overview of drought and heat-induced tree mortality reveals emerging climate change risks for forests
-
Greenhouse gas emissions have significantly altered global climate, and will continue to do so in the
future. Increases in the frequency, duration, and/or severity of drought and heat stress associated with
climate change could fundamentally alter the composition, structure, and biogeography of forests in
many regions. Of particular concern are potential increases in tree mortality associated with climateinduced
physiological stress and interactions with other climate-mediated processes such as insect
outbreaks and wildfire. Despite this risk, existing projections of tree mortality are based on models that
lack functionally realistic mortality mechanisms, and there has been no attempt to track observations of
climate-driven tree mortality globally. Here we present the first global assessment of recent tree
mortality attributed to drought and heat stress. Although episodic mortality occurs in the absence of
climate change, studies compiled here suggest that at least some of the world’s forested ecosystems
already may be responding to climate change and raise concern that forests may become increasingly
vulnerable to higher background tree mortality rates and die-off in response to future warming and
drought, even in environments that are not normally considered water-limited. This further suggests
risks to ecosystem services, including the loss of sequestered forest carbon and associated atmospheric
feedbacks. Our review also identifies key information gaps and scientific uncertainties that currently
hinder our ability to predict tree mortality in response to climate change and emphasizes the need for a
globally coordinated observation system. Overall, our review reveals the potential for amplified tree
mortality due to drought and heat in forests worldwide.
Located in
Resources
/
Climate Science Documents
-
Are conservation organizations configured for effective adaptation to global change?
-
Conservation organizations must adapt to respond to the ecological impacts of global change. Numerous
changes to conservation actions (eg facilitated ecological transitions, managed relocations, or increased corridordevelopment) have been recommended, but some institutional restructuring within organizations may also be needed. Here we discuss the capacity of conservation organizations to adapt to changing environmental
conditions, focusing primarily on public agencies and nonprofits active in land protection and management
in the US. After first reviewing how these organizations anticipate and detect impacts affecting target
species and ecosystems, we then discuss whether they are sufficiently flexible to prepare and respond by reallocating funding, staff, or other resources. We raise new hypotheses about how the configuration of different
organizations enables them to protect particular conservation targets and manage for particular biophysical
changes that require coordinated management actions over different spatial and temporal scales. Finally, we
provide a discussion resource to help conservation organizations assess their capacity to adapt.
Located in
Resources
/
Climate Science Documents
-
Impacts of mountaintop mining on terrestrial ecosystem integrity: identifying landscape thresholds for avian species in the central Appalachians, United States
-
Reclaimed mine-dominated landscapes (less forest and more grassland/shrubland cover) elicited more negative (57 %) than positive (39 %) species responses. Negative thresholds for each landscape metric generally occurred at lower values than positive thresholds, thus negatively responding species were
detrimentally affected before positively responding species benefitted. Forest interior birds generally
responded negatively to landscape metric thresholds, interior edge species responses were mixed, and early
successional birds responded positively. The forest interior guild declined most at 4 % forest loss, while
the shrubland guild increased greatest after 52 % loss
Located in
Resources
/
Climate Science Documents
-
Temporal dynamics of a commensal network of cavity-nesting vertebrates: increased diversity during an insect outbreak
-
Network analysis offers insight into the structure and function of ecological
communities, but little is known about how empirical networks change over time during
perturbations. ‘‘Nest webs’’ are commensal networks that link secondary cavity-nesting
vertebrates (e.g., bluebirds, ducks, and squirrels, which depend on tree cavities for nesting)
with the excavators (e.g., woodpeckers) that produce cavities. In central British Columbia,
Canada, Northern Flicker (Colaptes auratus) is considered a keystone excavator, providing
most cavities for secondary cavity-nesters. However, roles of species in the network, and
overall network architecture, are expected to vary with population fluctuations. Many
excavator species increased in abundance in association with a pulse of food (adult and larval
beetles) during an outbreak of mountain pine beetle (Dendroctonus ponderosae), which peaked
in 2003–2004. We studied nest-web dynamics from 1998 to 2011 to determine how network
architecture changed during this resource pulse.Cavity availability increased at the onset of the beetle outbreak and peaked in 2005. During and after the outbreak, secondary cavity-nesters increased their use of cavities made by five species of beetle-eating excavators, and decreased their use of flicker cavities. We found low link turnover, with 74% of links conserved from year to year. Nevertheless, the network
increased in evenness and diversity of interactions, and declined slightly in nestedness and
niche overlap. These patterns remained evident seven years after the beetle outbreak,
suggesting a legacy effect. In contrast to previous snapshot studies of nest webs, our dynamic approach reveals how the role of each cavity producer, and thus quantitative network architecture, can vary over
time. The increase in interaction diversity with the beetle outbreak adds to growing evidence
that insect outbreaks can increase components of biodiversity in forest ecosystems at various
temporal scales. The observed changes in (quantitative) network architecture contrast with the
relatively stable (qualitative) architecture of empirical mutualistic networks that have been
studied to date. However, they are consistent with recent theory on the importance of
population fluctuations in driving network architecture. Our results support the view that
models should allow for the possibility of rewiring (species switching partners) to avoid
overestimation of secondary extinction risk.
Located in
Resources
/
Climate Science Documents
-
Growing feedback from ocean carbon to climate
-
The finding that feedbacks between the ocean’s carbon cycle and climate may
become larger than terrestrial carbon–climate feedbacks has implications for the
socio-economic effects of today’s fossil-fuel emissions.
Located in
Resources
/
Climate Science Documents
-
Climate: Sawyer predicted rate of warming in 1972
-
Excerpt: "In four pages Sawyer summarized what was known about the role of carbon dioxide in enhancing the natural greenhouse effect, and made a remarkable prediction of the warming expected at the end of the twentieth century.He concluded that the 25% increase in atmospheric carbon dioxide predicted to occur by 2000 corresponded to an increase of 0.6 °C in world temperature..... In fact the global surface temperature rose about 0.5 °C between the early 1970s and2000. Considering that global temperatures had, if anything, been falling in the decades leading up to the early 1970s, Sawyer’s prediction of a reversal of this trend, and of the correct magnitude of the warming, is perhaps the most remarkable long-range forecast ever made.
Despite huge efforts, and advances in the science, the scientific consensus on the amount of global warming
expected from increasing atmospheric carbon dioxide concentrations has changed little from that in Sawyer’s time.
Located in
Resources
/
Climate Science Documents
-
Biodiversity gains from efficient use of private sponsorship for flagship species conservation
-
To address the global extinction crisis, both efficient use of existing conservation funding and new sources of funding are vital. Private sponsorship of charismatic ‘flagship’ species conservation represents an important source of new funding, but has been criticized as being inefficient. However, the ancillary benefits of privately sponsored flagship species conservation via actions benefiting other species have not been quantified, nor havethe benefits of incorporating such sponsorship into objective prioritization protocols. Here, we use a comprehensive dataset of conservation actions for the 700 most threatened species in New Zealand to examine the potential biodiversity gains from national private flagship species sponsorship programmes. We find that private funding for flagship species can clearly result in additional species and phylogenetic diversity conserved, via conservation actions shared with other species. When private flagship species funding is incorporated into a prioritization protocol to preferentially sponsor shared actions, expected gains can be more than doubled. However, these gains are consistently smaller than expected gains in a hypothetical scenario where private funding could be optimally allocated among all threatened species. We recommend integrating private sponsorship of flagship species into objective prioritization protocols to sponsor efficient actions that maximize biodiversity gains, or wherever possible, encouraging
private donations for broader biodiversity goals.
Located in
Resources
/
Climate Science Documents
