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Conservation VALUE OF ROADLESS AREAS FOR VULNERABLE FISH AND Wildlife Species in the Crown of the Continent Ecosystem, Montana
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The Crown of the Continent Ecosystem is one of the most spectacular landscapes
in the world and most ecologically intact ecosystem remaining in the
contiguous United States. Straddling the Continental Divide in the heart of the
Rocky Mountains, the Crown of the Continent Ecosystem extends for >250
miles from the fabled Blackfoot River valley in northwest Montana north to Elk
Pass south of Banff and Kootenay National Parks in Canada. It reaches from
the short-grass plains along the eastern slopes of the Rockies westward nearly
100 miles to the Flathead and Kootenai River valleys. The Crown sparkles with
a variety of dramatic landscapes, clean sources of blue waters, and diversity of
plants and animals.Over the past century, citizens and government leaders have worked hard to
save the core of this splendid ecosystem in Montana by establishing world-class
parks and wildernesses – coupled with conservation of critical wildlife habitat
on state and private lands along the periphery. These include jewels such as
Glacier National Park, the Bob Marshall-Scapegoat-Great Bear Wilderness,
the first-ever Tribal Wilderness in the Mission Mountains, numerous State of
Montana Wildlife Management Areas (WMAs), and vital private lands through
land trusts such as The Nature Conservancy. Their combined efforts have
protected 3.3 million acres and constitute a truly impressive commitment to
conservation. It was a remarkable legacy and great gift …but, in the face of new
challenges, it may not have been enough.
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Projections of Future Drought in the Continental United States and Mexico
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Using the Palmer drought severity index, the ability of 19 state-of-the-art climate models to reproduce observed
statistics of drought over North America is examined. It is found that correction of substantial biases in
the models’ surface air temperature and precipitation fields is necessary. However, even after a bias correction,
there are significant differences in the models’ ability to reproduce observations. Using metrics based on the
ability to reproduce observed temporal and spatial patterns of drought, the relationship between model performance
in simulating present-day drought characteristics and their differences in projections of future drought
changes is investigated. It is found that all models project increases in future drought frequency and severity.
However, using the metrics presented here to increase confidence in the multimodel projection is complicated
by a correlation between models’ drought metric skill and climate sensitivity. The effect of this sampling error
can be removed by changing how the projection is presented, from a projection based on a specific time interval
to a projection based on a specified temperature change. This modified class of projections has reduced
intermodel uncertainty and could be suitable for a wide range of climate change impacts projections.
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When It Rains, It Pours Global Warming and the Increase in Extreme Precipitation from 1948 to 2011
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Global warming is happening now and
its effects are being felt in the United
States and around the world. Among
the expected consequences of global warming
is an increase in the heaviest rain and
snow storms, fueled by increased evaporation
and the ability of a warmer atmosphere
to hold more moisture.
An analysis of more than 80 million daily
precipitation records from across the contiguous
United States reveals that intense
rainstorms and snowstorms have already
become more frequent and more severe.
Extreme downpours are now happening
30 percent more often nationwide than
in 1948. In other words, large rain or
snowstorms that happened once every
12 months, on average, in the middle of
the 20th century now happen every nine
months. Moreover, the largest annual
storms now produce 10 percent more
precipitation, on average.
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‘As Earth’s testimonies tell’: wilderness conservation in a changing world
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Too often, wilderness conservation ignores a temporal perspective greater than the past
50 years, yet a long-term perspective (centuries to millennia) reveals the dynamic nature
of many ecosystems. Analysis of fossil pollen, charcoal and stable isotopes, combined
with historical analyses and archaeology can reveal how ongoing interactions between
climatic change, human activities and other disturbances have shaped today’s landscapes
over thousands of years. This interdisciplinary approach can inform wilderness
conservation and also contribute to interpreting current trends and predicting how
ecosystems might respond to future climate change. In this paper, we review literature
that reveals how increasing collaboration among palaeoecologists, archaeologists,
historians, anthropologists and ecologists is improving understanding of ecological
complexity. Drawing on case studies from forested and non-forested ecosystems in
Europe, the Americas, Africa and Australia, we discuss how this integrated approach can
inform wilderness conservation and ecosystem management.
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Wildfire and fuel treatment effects on forest carbon dynamics in the western United States
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Sequestration of carbon (C) in forests has the potential to mitigate the effects of climate change by offsetting
future emissions of greenhouse gases. However, in dry temperate forests, wildfire is a natural disturbance
agent with the potential to release large fluxes of C into the atmosphere. Climate-driven
increases in wildfire extent and severity are expected to increase the risks of reversal to C stores and
affect the potential of dry forests to sequester C. In the western United States, fuel treatments that
successfully reduce surface fuels in dry forests can mitigate the spread and severity of wildfire, while
reducing both tree mortality and emissions from wildfire. However, heterogeneous burn environments,
site-specific variability in post-fire ecosystem response, and uncertainty in future fire frequency and
extent complicate assessments of long-term (decades to centuries) C dynamics across large landscapes.
Results of studies on the effects of fuel treatments and wildfires on long-term C retention across large
landscapes are limited and equivocal. Stand-scale studies, empirical and modeled, describe a wide range
of total treatment costs (12–116 Mg C ha1
) and reductions in wildfire emissions between treated and
untreated stands (1–40 Mg C ha1
). Conclusions suggest the direction (source, sink) and magnitude of
net C effects from fuel treatments are similarly variable (33 Mg C ha1 to +3 Mg C ha1
). Studies at large
spatial and temporal scales suggest that there is a low likelihood of high-severity wildfire events interacting
with treated forests, negating any expected C benefit from fuels reduction. The frequency, extent,
and severity of wildfire are expected to increase as a result of changing climate, and additional information
on C response to management and disturbance scenarios is needed improve the accuracy and usefulness
of assessments of fuel treatment and wildfire effects on C dynamics.
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The anatomy of predator–prey dynamics in a changing climate
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1. Humans are increasingly influencing global climate and regional predator assemblages,
yet a mechanistic understanding of how climate and predation interact to affect
fluctuations in prey populations is currently lacking.
2. Here we develop a modelling framework to explore the effects of different predation
strategies on the response of age-structured prey populations to a changing climate.
3. We show that predation acts in opposition to temporal correlation in climatic
conditions to suppress prey population fluctuations.
4. Ambush predators such as lions are shown to be more effective at suppressing
fluctuations in their prey than cursorial predators such as wolves, which chase down
prey over long distances, because they are more effective predators on prime-aged adults.
5. We model climate as a Markov process and explore the consequences of future
changes in climatic autocorrelation for population dynamics. We show that the presence
of healthy predator populations will be particularly important in dampening prey
population fluctuations if temporal correlation in climatic conditions increases in the
future.
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Animal Versus Wind Dispersal and the Robustness of Tree Species to Deforestation
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Studies suggest that populations of different species do not decline equally after habitat loss. However, empirical tests have been confined to fine spatiotemporal scales and have rarely included plants. Using data from 89,365 forest survey plots covering peninsular Spain, we explored, for each of 34 common tree species, the relationship between probability of occurrence and the local cover of remaining forest. Twenty-four species showed a significant negative response to forest loss, so that decreased forest cover had
a negative effect on tree diversity, but the responses of individual species were highly variable. Animal-dispersed species were less vulnerable to forest loss, with six showing positive responses to decreased forest cover. The results imply that plant-animal interactions help prevent the collapse of forest communities that suffer habitat destruction.
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Large in-stream wood studies: a call for common metrics
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During the past decade, research on large in-stream wood has expanded beyond North America’s Pacifi c Northwest
to diverse environments and has shifted toward increasingly holistic perspectives that incorporate processes of wood recruitment,
retention, and loss at scales from channel segments to entire watersheds. Syntheses of this rapidly expanding literature can be
facilitated by agreement on primary variables and methods of measurement. In this paper we address these issues by listing the
variables that we consider fundamental to studies of in-stream wood, discussing the sources of variability in their measurement,
and suggesting more consistency in future studies. We recommend 23 variables for all studies of in-stream wood, as well as
another 12 variables that we suggest for studies with more specifi c objectives. Each of these variables relates either to the size
and characteristics of in-stream wood, to the geomorphic features of the channel and valley, or to the ecological characteristics
of the riparian zone adjacent to the study reach. The variables were derived from an overview of those cited in the literature and
from our collective fi eld experiences.
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Landscape-scale carbon storage associated with beaver dams
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Beaver meadows form when beaver dams promote
prolonged overbank flooding and floodplain retention of
sediment and organic matter. Extensive beaver meadows form
in broad, low-gradient valley segments upstream from glacial
terminal moraines. Surveyed sediment volume and total
organic carbon content in beaver meadows on the eastern side
of Rocky Mountain National Park are extrapolated to create a
first-order approximation of landscape-scale carbon storage in
these meadows relative to adjacent uplands. Differences in
total organic carbon between abandoned and active beaver
meadows suggest that valley-bottom carbon storage has
declined substantially as beaver have disappeared and
meadows have dried. Relict beaver meadows represent ~8%
of total carbon storage within the landscape, but the value was
closer to 23% when beaver actively maintained wet meadows.
These changes reflect the general magnitude of cumulative
effects in heterotrophic respiration and organic matter
oxidation associated with historical declines in beaver
populations across the continent
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Carbon sequestration in the U.S. forest sector from 1990 to 2010
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From 1990 through 2005, the forest sector (including forests and wood products) sequestered an average 162 Tg C year1 . In 2005, 49% of the total forest sector sequestration was in live and dead trees, 27% was
in wood products in landfills, with the remainder in down dead wood, wood products in use, and forest floor and soil. The pools with the largest carbon stocks were not the same as those with the largest sequestration rates, except for the tree pool. For example, landfilled wood products comprise only 3% of total stocks but account for 27% of carbon sequestration. Conversely, forest soils comprise 48% of total stocks but account for only 2% of carbon sequestration. For the tree pool, the spatial pattern of carbon stocks was dissimilar to that of carbon flux. On an area basis, tree carbon stocks were highest in the Pacific Northwest, while changes were generally greatest in the upper Midwest and the Northeast. Net carbon sequestration in the forest sector in 2005 offset 10% of U.S. CO2 emissions. In the near future, we project that U.S. forests will continue to sequester carbon at a rate similar to that in recent years. Based on a comparison of our estimates to a compilation of land-based estimates of non-forest carbon sinks from the literature, we estimate that the conterminous U.S. annually sequesters 149–330 Tg C year1. Forests, urban trees, and wood products are responsible for 65–91% of this sink.
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