scholarly journals Community‐level responses to climate change in forests of the eastern United States

2020 ◽  
Vol 29 (8) ◽  
pp. 1299-1314 ◽  
Author(s):  
Jonathan A. Knott ◽  
Michael A. Jenkins ◽  
Christopher M. Oswalt ◽  
Songlin Fei
2020 ◽  
Vol 262 ◽  
pp. 114351 ◽  
Author(s):  
T.C. McDonnell ◽  
G.J. Reinds ◽  
G.W.W. Wamelink ◽  
P.W. Goedhart ◽  
M. Posch ◽  
...  

2016 ◽  
Author(s):  
Lu Shen ◽  
Loretta J. Mickley ◽  
Lee T. Murray

Abstract. We use a statistical model to investigate the effect of 2000–2050 climate change on fine particulate matter (PM2.5) air quality across the contiguous United States. By applying observed relationships of PM2.5 and meteorology to the IPCC Coupled Model Intercomparision Project Phase 5 (CMIP5) archives, we bypass many of the uncertainties inherent in chemistry-climate models. Our approach uses both the relationships between PM2.5 and local meteorology as well as the synoptic circulation patterns, defined as the Singular Value Decomposition (SVD) pattern of the spatial correlations between PM2.5 and meteorological variables in the surrounding region. Using an ensemble of 17 GCMs under the RCP4.5 scenario, we project an increase of ~ 1 μg m−3 in annual mean PM2.5 in the eastern US and a decrease of 0.3–1.2 μg m−3 in the Intermountain West by the 2050s, assuming present-day anthropogenic sources of PM2.5. Mean summertime PM2.5 increases as much as 2–3 μg m−3 in the eastern United States due to faster oxidation rates and greater mass of organic carbon from biogenic emissions. Mean wintertime PM2.5 decreases by 0.3–3 μg m−3 over most regions in United States, likely due to the volatilization of ammonium nitrate. Our approach provides an efficient method to calculate the climate penalty or benefit on air quality across a range of models and scenarios. We find that current atmospheric chemistry models may underestimate or even fail to capture the strongly positive sensitivity of monthly mean PM2.5 to temperature in the eastern United States in summer, and may underestimate future changes in PM2.5 in a warmer climate. In GEOS-Chem, the underestimate in monthly mean PM2.5-temperature relationship in the East in summer is likely caused by overly strong negative sensitivity of monthly mean low cloud fraction to temperature in the assimilated meteorology (~ −0.04 K−1), compared to the weak sensitivity implied by satellite observations (±0.01 K−1). The strong negative dependence of low cloud cover on temperature, in turn, causes the modeled rates of sulfate aqueous oxidation to diminish too rapidly as temperatures rise, leading to the underestimate of sulfate-temperature slopes, especially in the South. Our work underscores the importance of evaluating the sensitivity of PM2.5 to its key controlling meteorological variables in climate-chemistry models on multiple timescales before they are applied to project future air quality.


2019 ◽  
Vol 118 (1) ◽  
pp. 14-27
Author(s):  
Anna O Conrad ◽  
Ellen V Crocker ◽  
Xiaoshu Li ◽  
William R Thomas ◽  
Thomas O Ochuodho ◽  
...  

Abstract Oaks (Quercus spp.) are keystone species in many ecosystems and are ecologically as well as economically valuable. The objective of this study was to gather and evaluate information from a diverse group of oak experts on current and future biotic and abiotic threats to oaks in the eastern United States. Using a Delphi survey method with three iterative surveys, we found that oak decline and climate change were identified as critical current and future threats, respectively, in this region. Focusing on climate change, experts were asked a series of questions to assess its potential future temporal and spatial impact on oaks. With respect to climate change, the majority of experts surveyed believe climate change will manifest gradually, although they were generally uncertain about the geographical distribution of climate change in the future, i.e., the areas where oaks are likely to be impacted by climate change in the future. New/emerging pests and pathogens were seen as the most critical future threat by the third survey round. Results from this study can be used to better inform management practices and research priorities for ensuring resilient oak resources for the future.


1994 ◽  
Vol 9 (1) ◽  
pp. 15-30 ◽  
Author(s):  
J.C. Randolph ◽  
Jae K. Lee

2014 ◽  
Vol 487 ◽  
pp. 299-312 ◽  
Author(s):  
Athanasios G. Megaritis ◽  
Benjamin N. Murphy ◽  
Pavan N. Racherla ◽  
Peter J. Adams ◽  
Spyros N. Pandis

2019 ◽  
Vol 5 (4) ◽  
pp. eaav6358 ◽  
Author(s):  
Insu Jo ◽  
Songlin Fei ◽  
Christopher M. Oswalt ◽  
Grant M. Domke ◽  
Richard P. Phillips

Plant-fungal symbioses play critical roles in vegetation dynamics and nutrient cycling, modulating the impacts of global changes on ecosystem functioning. Here, we used forest inventory data consisting of more than 3 million trees to develop a spatially resolved “mycorrhizal tree map” of the contiguous United States. We show that abundances of the two dominant mycorrhizal tree groups—arbuscular mycorrhizal (AM) and ectomycorrhizal trees—are associated primarily with climate. Further, we show that anthropogenic influences, primarily nitrogen (N) deposition and fire suppression, in concert with climate change, have increased AM tree dominance during the past three decades in the eastern United States. Given that most AM-dominated forests in this region are underlain by soils with high N availability, our results suggest that the increasing abundance of AM trees has the potential to induce nutrient acceleration, with critical consequences for forest productivity, ecosystem carbon and nutrient retention, and feedbacks to climate change.


Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 230-238 ◽  
Author(s):  
Graeme W. Bourdôt ◽  
Shona L. Lamoureaux ◽  
Michael S. Watt ◽  
Darren J. Kriticos

Tall buttercup, a native of central and northern Europe, has become naturalized in the United States and Canada, and in South Africa, Tasmania and New Zealand. In Canada and New Zealand it has become an economically significant weed in cattle-grazed pastures. In this study we develop a CLIMEX model for tall buttercup and use it to project the weed's potential distribution under current and future climates and in the presence and absence of irrigation. There was close concordance between the model's projection of suitable climate and recorded observations of the species. The projection was highly sensitive to irrigation; the area of potentially suitable land globally increasing by 30% (from 34 to 45 million km2) under current climate when a “top-up” irrigation regime (rainfall topped up 4 mm d−1 on irrigable land), was included in the model. Most of the area that becomes suitable under irrigation is located in central Asia and central North America. By contrast, climate change is projected to have the opposite effect; the potential global distribution diminishing by 18% (from 34 to 28 million km2). This range contraction was the net result of a northward expansion in the northern limit for the species in Canada and the Russian Federation, and a relatively larger increase in the land area becoming unsuitable mainly in central Asia and south eastern United States.


Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 989 ◽  
Author(s):  
Louis R. Iverson ◽  
Anantha M. Prasad ◽  
Matthew P. Peters ◽  
Stephen N. Matthews

We modeled and combined outputs for 125 tree species for the eastern United States, using habitat suitability and colonization potential models along with an evaluation of adaptation traits. These outputs allowed, for the first time, the compilation of tree species’ current and future potential for each unit of 55 national forests and grasslands and 469 1 × 1 degree grids across the eastern United States. A habitat suitability model, a migration simulation model, and an assessment based on biological and disturbance factors were used with United States Forest Service Forest Inventory and Analysis data to evaluate species potential to migrate or infill naturally into suitable habitats over the next 100 years. We describe a suite of variables, by species, for each unique geographic unit, packaged as summary tables describing current abundance, potential future change in suitable habitat, adaptability, and capability to cope with the changing climate, and colonization likelihood over 100 years. This resulting synthesis and summation effort, culminating over two decades of work, provides a detailed data set that incorporates habitat quality, land cover, and dispersal potential, spatially constrained, for nearly all the tree species of the eastern United States. These tables and maps provide an estimate of potential species trends out 100 years, intended to deliver managers and publics with practical tools to reduce the vast set of decisions before them as they proactively manage tree species in the face of climate change.


2007 ◽  
Vol 7 (4) ◽  
pp. 9867-9897 ◽  
Author(s):  
P. N. Racherla ◽  
P. J. Adams

Abstract. We examined the response of surface ozone to future climate change over the eastern United States by performing simulations corresponding to present (1990s) and future (2050s) climates using an integrated model of global climate, tropospheric gas-phase chemistry, and aerosols. A future climate has been imposed using ocean boundary conditions corresponding to the IPCC SRES A2 scenario for the 2050 s decade, resulting in an increase in the global annual-average surface air temperature by 1.7°C, with a 1.4°C increase over the surface layer of the eastern United States. Present-day anthropogenic emissions and CO2/CH4 mixing ratios have been used in both simulations while climate-sensitive natural emissions were allowed to vary with the simulated climate. There is practically zero change in the spatiotemporally averaged ozone mixing ratios predicted over the eastern United States. However, the severity and frequency of ozone episodes over the eastern United States increased due to future climate change, primarily as a result of increased ozone chemical production due to increased natural isoprene emissions. The 95th percentile ozone mixing ratio increased by 5 ppbv and the largest frequency increase occured in the 80–90 ppbv range. The most substantial and statistically significant (p-value <0.05) increases in episode frequency occurred over the southeast and midatlantic United States, largely as a result of 20% higher annual-average natural isoprene emissions. Increased chemical production and shorter average lifetime are consistent features of the predicted seasonal surface ozone response, with the former's magnitude for a location largely a function of increased natural isoprene emissions, and the latter largely due to faster dry deposition removal rates. Future climate change is also predicted to lengthen the ozone season over the eastern United States to include late spring and early fall. Significant interannual variability is observed in the frequency of ozone episodes and we find that it is necessary to utilize 5 years or more of simulation data in order to separate the effects of interannual variability and climate change on ozone episodes.


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