-
Early Warnings of Regime Shifts: A Whole-Ecosystem Experiment
-
Catastrophic ecological regime shifts may be announced in advance by statistical early warning signals such as slowing return rates from perturbation and rising variance. The theoretical background for these indicators is rich, but real-world tests are rare, especially for whole ecosystems. We tested the hypothesis that these statistics would be early warning signals for an experimentally induced regime shift in an aquatic food web. We gradually added top predators to a lake over 3 years to destabilize its food web. An adjacent lake was monitored simultaneously as a reference ecosystem. Warning signals of a regime shift were evident in the manipulated lake during reorganization of the food web more than a year before the food web transition was complete, corroborating theory for leading indicators of ecological regime shifts.
Critical slowing down
Located in
Resources
/
Climate Science Documents
-
Education for a Sustainable Future
-
Sustainability is being integrated into higher-education institutions’ mission and planning, curricula, research, student life, and operations.
Located in
Resources
/
Climate Science Documents
-
Biodiversity in a Warmer World
-
A new framework helps to understand how species ranges change under global warming.
Located in
Resources
/
Climate Science Documents
-
Complexity of Coupled Human and Natural Systems
-
Integrated studies of coupled human and natural systems reveal new and complex patterns and processes not evident when studied by social or natural scientists separately. Synthesis of six case studies from around the world shows that couplings between human and natural systems vary across space, time, and organizational units. They also exhibit nonlinear dynamics with thresholds, reciprocal feedback loops, time lags, resilience, heterogeneity, and surprises. Furthermore, past couplings have legacy effects on present conditions and future possibilities.
Located in
Resources
/
Climate Science Documents
-
Biodiversity Under Global Change
-
Many common plant species, such as prairie grasses, have evolved traits for the efficient capture and use of two key resources that limit terrestrial productivity: nitrogen (N) and carbon dioxide (CO2). Over the past 60 years, human activity has vastly increased the availability of these resources. Atmospheric CO2 concentration has increased by 40%, and N availability has more than doubled. These changes are likely to have important consequences for species interactions, community structure, and ecosystem functioning. On
page 1399 of this issue, Reich investigates one important consequence, biodiversity loss, based on a long-term elevated CO2 and nitrogen fertilization experiment.
Located in
Resources
/
Climate Science Documents
-
Amid Worrisome Signs of Warming, ‘Climate Fatigue’ Sets In
-
As scientists debate whether climate is changing faster than anticipated, some worry that a
drumbeat of dire warnings may be helping to erode U.S. public concerns about global warming
Located in
Resources
/
Climate Science Documents
-
Biodiversity and Climate Change
-
Efforts to elucidate the effect of climate change on biodiversity with detailed data sets and refined models reach novel conclusions.
Located in
Resources
/
Climate Science Documents
-
Drought Sensitivity of the Amazon Rainforest
-
Amazon forests are a key but poorly understood component of the global carbon cycle. If, as
anticipated, they dry this century, they might accelerate climate change through carbon losses and
changed surface energy balances. We used records from multiple long-term monitoring plots across
Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events.
Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts
observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected
to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per
hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 × 1015 to
1.6 × 1015 grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the
potential for large carbon losses to exert feedback on climate change.
Located in
Resources
/
Climate Science Documents
-
A-maize-ing Diversity
-
Analysis of a new maize resource reveals that a large number of genetic loci with small effects may underlie the wide variation seen in traits such as flowering time.
Located in
Resources
/
Climate Science Documents
-
Ecological Restoration in the Light of Ecological History
-
Ecological history plays many roles in ecological restoration, most notably as a tool to identify and
characterize appropriate targets for restoration efforts. However, ecological history also reveals deep human
imprints on many ecological systems and indicates that secular climate change has kept many targets
moving at centennial to millennial time scales. Past and ongoing environmental changes ensure that many
historical restoration targets will be unsustainable in the coming decades. Ecological restoration efforts
should aim to conserve and restore historical ecosystems where viable, while simultaneously preparing to
design or steer emerging novel ecosystems to ensure maintenance of ecological goods and services.
Located in
Resources
/
Climate Science Documents
