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Petit 1978.pdf
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PEK-RIC
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Petit 1979.pdf
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Pheasants Forever, Quail Forever, and WLFW East Region Webinar Series
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Pheasants Forever & Quail Forever, in partnership with USDA-NRCS’s Working Lands for Wildlife, has reformed the WLFW Pollinator Conservation webinar series to include broader topics and changed platforms to Zoom. This series aims to enhance understanding, confidence, and knowledge of conservation concepts. It is designed for conservation professionals working in the WLFW East Region. NRCS staff and partner organizations are welcome to attend (click image for more details), so please feel free to share it with your field staff.
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Phenology Feedbacks on Climate Change
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A longer growing season as a result of climate
change will in turn affect climate through
biogeochemical and biophysical effects.
SCIENCE VOL 324
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PHENOLOGY OF MIXED WOODY–HERBACEOUS ECOSYSTEMS FOLLOWING EXTREME EVENTS: NET AND DIFFERENTIAL RESPONSES
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We present responses of a mixed woody–herbaceous ecosystem type to an extreme event: regional-scale pinon pine mortality following an extended drought and the subsequent herbaceous green-up following the first wet period after the drought. This example highlights how reductions in greenness of the slower, more stable evergreen woody component can rapidly be offset by increases associated with resources made available to the relatively more responsive herbaceous component. We hypothesize that such two-phase phenological responses to extreme events are characteristic of many mixed woody– herbaceous ecosystems.
Key words: die-off; disturbance; drought; extreme events; fire; Mesita del Buey; mortality; normalized difference vegetation index; phenology; pin ̃on; semiarid woodlands; woody and herbaceous plants.
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Philadelphia Record 1902.pdf
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Phillips, Randall
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Photoperiodic regulation of the seasonal pattern of photosynthetic capacity and the implications for carbon cycling
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Although temperature is an important driver of seasonal changes in photosynthetic physiology, photoperiod also regulates leaf activity. Climate change will extend growing seasons if temperature cues predominate, but photoperiod-controlled species will show limited responsiveness to warming. We show that photoperiod explains more seasonal variation in photosynthetic activity across 23 tree species than temperature. Although leaves remain green, photosynthetic capacity peaks just after summer solstice and declines with decreasing photoperiod, before air temperatures peak. In support of these findings, saplings grown at constant temperature but exposed to an extended photoperiod maintained high photosynthetic capacity, but photosynthetic activity declined in saplings experiencing a naturally shortening photoperiod; leaves remained equally green in both treatments. Incorporating a photo- periodic correction of photosynthetic physiology into a global-scale terrestrial carbon-cycle model significantly improves predictions of seasonal atmospheric CO2 cycling, demonstrating the benefit of such a function in coupled climate system models. Accounting for photo- period-induced seasonality in photosynthetic parameters reduces modeled global gross primary production 2.5% (∼4 PgC y−1), result- ing in a >3% (∼2 PgC y−1) decrease of net primary production. Such a correction is also needed in models estimating current carbon up- take based on remotely sensed greenness. Photoperiod-associated declines in photosynthetic capacity could limit autumn carbon gain in forests, even if warming delays leaf senescence.
day length | gross primary productivity | carbon sequestration | leaf area index | evapotranspiration
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Phylogenetic and functional diversity in large carnivore assemblages
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Large terrestrial carnivores are important ecological components and promi- nent flagship species, but are often extinction prone owing to a combination of biological traits and high levels of human persecution. This study com- bines phylogenetic and functional diversity evaluations of global and continental large carnivore assemblages to provide a framework for conser- vation prioritization both between and within assemblages. Species-rich assemblages of large carnivores simultaneously had high phylogenetic and functional diversity, but species contributions to phylogenetic and func- tional diversity components were not positively correlated. The results further provide ecological justification for the largest carnivore species as a focus for conservation action, and suggests that range contraction is a likely cause of diminishing carnivore ecosystem function. This study high- lights that preserving species-rich carnivore assemblages will capture both high phylogenetic and functional diversity, but that prioritizing species within assemblages will involve trade-offs between optimizing contempor- ary ecosystem function versus the evolutionary potential for future ecosystem performance. Carnivora, predation, ecosystem function, conservation priorities, biodiversity
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Phylogenetic patterns of species loss in Thoreau’s woods are driven by climate change
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Climate change has led to major changes in the phenology (the
timing of seasonal activities, such as flowering) of some species but
not others. The extent to which flowering-time response to temperature
is shared among closely related species might have
important consequences for community-wide patterns of species
loss under rapid climate change. Henry David Thoreau initiated a
dataset of the Concord, Massachusetts, flora that spans !150 years
and provides information on changes in species abundance and
flowering time. When these data are analyzed in a phylogenetic
context, they indicate that change in abundance is strongly correlated
with flowering-time response. Species that do not respond to
temperature have decreased greatly in abundance, and include
among others anemones and buttercups [Ranunculaceae pro parte
(p.p.)], asters and campanulas (Asterales), bluets (Rubiaceae p.p.),
bladderworts (Lentibulariaceae), dogwoods (Cornaceae), lilies (Liliales),
mints (Lamiaceae p.p.), orchids (Orchidaceae), roses (Rosaceae
p.p.), saxifrages (Saxifragales), and violets (Malpighiales).
Because flowering-time response traits are shared among closely
related species, our findings suggest that climate change has
affected and will likely continue to shape the phylogenetically
biased pattern of species loss in Thoreau’s woods
PNAS ! November 4, 2008 ! vol. 105 ! no. 44 ! 17029–17033
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