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America’s remaining grassland in the Prairie Pothole Region (PPR) is at risk of being lost to crop production. When crop prices are high, like the historically high corn prices that the U.S. experienced between 2008 and 2014, the risk of grassland conversion is even higher. Changing climate will add uncertainties to any efforts toward conservation of grassland in the PPR. Grassland conversion to cropland in the region would imperil nesting waterfowl among other species and further impair water quality in the Mississippi watershed. In this project, we sought to contribute to the understanding of land conversion in the PPR with the aim to better target the use of public and private funds allocated toward incentivizing...
Greater sage-grouse (Centrocercus urophasianus) is a candidate for listing under the Endangered Species Act because of population and habitat fragmentation coupled with inadequate regulatory mechanisms to control development in critical areas. In addition to the current threats to habitat, each 1 degree celsius increase due to climate change is expected to result in an additional 87,000 km2 of sagebrush (Artemisia spp.) that will be converted to unsuitable habitat for sage-grouse. Thus, the future distribution and composition of sagebrush landscapes is likely to differ greatly from today’s configuration. We conducted a large, multi-objective project to identify: (1) characteristics of habitats required by sage-grouse,...
Monitoring vegetation phenology is critical for quantifying climate change impacts on ecosystems. We present an extensive dataset of 1783 site-years of phenological data derived from PhenoCam network imagery from 393 digital cameras, situated from tropics to tundra across a wide range of plant functional types, biomes, and climates. Most cameras are located in North America. Every half hour, cameras upload images to the PhenoCam server. Images are displayed in near-real time and provisional data products, including timeseries of the Green Chromatic Coordinate (Gcc), are made publicly available through the project web page (https://phenocam.sr.unh.edu/webcam/gallery/). Processing is conducted separately for each...
Abstract (from Remote Sensing in Ecology and Conservation): The use of unmanned aerial vehicles (UAVs) to map and monitor the environment has increased sharply in the last few years. Many individuals and organizations have purchased consumer‐grade UAVs, and commonly acquire aerial photographs to map land cover. The resulting ultra‐high‐resolution (sub‐decimeter‐resolution) imagery has high information content, but automating the extraction of this information to create accurate, wall‐to‐wall land‐cover maps is quite difficult. We introduce image‐processing workflows that are based on open‐source software and can be used to create land‐cover maps from ultra‐high‐resolution aerial imagery. We compared four machine‐learning...
Cheatgrass (Bromus tectorum) has increased the extent and frequency of fire and negatively affected native plant and animal species across the Intermountain West (USA). However, the strengths of association between cheatgrass occurrence or abundance and fire, livestock grazing, and precipitation are not well understood. We used 14 years of data from 417 sites across 10,000 km(2) in the central Great Basin to assess the effects of the foregoing predictors on cheatgrass occurrence and prevalence (i.e., given occurrence, the proportion of measurements in which the species was detected). We implemented hierarchical Bayesian models and considered covariates for which > 0.90 or < 0.10 of the posterior predictive mass...
Abstract (from IOP Science): Global agriculture is challenged to increase soil carbon sequestration and reduce greenhouse gas emissions while providing products for an increasing population. Growing crop production could be achieved through higher yield per hectare (i.e. intensive farming) or more hectares (extensive farming), which however, have different ecological and environmental consequences. Multiple lines of evidence indicate that expanding cropland for additional production may lead to loss of vegetation and soil carbon, and threaten the survival of wildlife. New concerns about the impacts of extensive farming have been raised for the US Corn Belt, one of the world's most productive regions, as cropland...
Abstract (from http://econpapers.repec.org/paper/agsaaea16/235895.htm): We evaluate the regional-level agricultural impacts of climate change in the Northern Great Plains. We first estimate a non-linear yield-weather relationship for all major commodities in the area: corn, soybeans, spring wheat and alfalfa. We separately identify benevolent and harmful temperature thresholds for each commodity, and control for severe-to-extreme dry/wet conditions in our yield models. Analyzing all major commodities in a region extends the existing literature beyond just one crop, most typically corn yields. Alfalfa is particularly interesting since it is a legume-crop that is substitutable with grasses as animal feed and rotated...
Abstract (from http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0099604): Across the globe, species distributions are changing in response to climate change and land use change. In parts of the southeastern United States, climate change is expected to result in the poleward range expansion of black mangroves ( Avicennia germinans) at the expense of some salt marsh vegetation. The morphology of A. germinans at its northern range limit is more shrub-like than in tropical climes in part due to the aboveground structural damage and vigorous multi-stem regrowth triggered by extreme winter temperatures. In this study, we developed aboveground allometric equations for freeze-affected black mangroves which...
Climate responses of sagebrush are needed to inform land managers of the stability and restoration of sagebrush ecosystems, which are an important but threatened habitat type. We evaluated climate responses of sagebrush using two approaches: (1) experimental manipulations of temperature and precipitation for natural plants in the field, and (2) assessment of how climate adaptation and weather have affected sagebrush seeding efforts on nearly 25 large-scale sagebrush seeding projects done over the past several decades. Experimental warming increased growth of sagebrush in high-elevation meadows in the Teton Mountains, but had marginal or no effect at lower elevations sites (near Twin Falls and Boise, Idaho, respectively)....
Abstract (from SpringerLink): Foundation plant species play a critical role in coastal wetlands, often modifying abiotic conditions that are too stressful for most organisms and providing the primary habitat features that support entire ecological communities. Here, we consider the influence of climatic drivers on the distribution of foundation plant species within coastal wetlands of the conterminous USA. Using region-level syntheses, we identified 24 dominant foundation plant species within 12 biogeographic regions, and we categorized species and biogeographic regions into four groups: graminoids, mangroves, succulents, and unvegetated. Literature searches were used to characterize the level of research directed...
Ground validation of satellite-based vegetation phenology has been challenging because ground phenology data are sparsely distributed and mostly observed from limited numbers of plant species at discrete phenophases. The recently developed PhenoCam network has measured continuous growth of vegetation canopy greenness that can be used to validate satellite-based vegetation phenology across a variety of plant functional types. In this study, we used PhenoCam green chromatic coordinate (GCC) in North America to evaluate grassland phenology derived from three types of MODIS vegetation indices: the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and a per-pixel GCC (GCCpp) which was computed...
Abstract From: (The growth and distribution of plant species in water limited environments is often limited by the atmospheric evaporative demands which us measured in terms of potential evaporation (PET). While PET estimated by different methods have been widely used to assess vegetation response to climate change, species distribution models offer unique opportunity to compare their efficiency in predicting habitat suitability of plant species. In this study, we perform the first multi-species comparison of two widely used metrics of PET i.e., Penman-Monteith and Thornthwaite, and show how they result in similar or different on projected distribution of water limited species and potential consequences on their...
Observations of vegetation phenology at regional-to-global scales provide important information regarding seasonal variation in the fluxes of energy, carbon, and water between the biosphere and the atmosphere. Numerous algorithms have been developed to estimate phenological transition dates using time series of remotely sensed spectral vegetation indices. A key challenge, however, is that different algorithms provide inconsistent results. This study provides a comprehensive comparison of start of season (SOS) and end of season (EOS) phenological transition dates estimated from 500 m MODIS data based on two widely used sources of such data: the TIMESAT program and the MODIS Global Land Cover Dynamics (MLCD) product....
Near surface (i.e., camera) and satellite remote sensing metrics have become widely used indicators of plant growing seasons. While robust linkages have been established between field metrics and ecosystem exchange in many land cover types, assessment of how well remotely-derived season start and end dates depict field conditions in arid ecosystems remain unknown. We evaluated the correspondence between field measures of start (SOS; leaves unfolded and canopy greenness >0) and end of season (EOS) and canopy greenness for two widespread species in southwestern U.S. ecosystems with those metrics estimated from near-surface cameras and MODIS NDVI for five years (2012–2016). Using Timesat software to estimate SOS and...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/9781119011705.ch10/summary): This chapter discusses an approach that uses MC1 results to create climate-informed state-and-transition simulation model (cSTSMs) in two contrasting landscapes: dry forests in central Oregon and wet forests in western Washington. The studies presented here examine trends in different socioecological values under different climate and management assumptions using a dynamic global vegetation model/STSM approach. The authors found that simulated management actions did not prevent climate-induced vegetation change. Simulated management did in some cases promote desired forest structures and increase resilience to climate change....
Land managers in the Pacific Northwest have reported a need for updated scientific information on the ecology and management of mixed-conifer forests east of the Cascade Range in Oregon and Washington. Of particular concern are the moist mixed-conifer forests, which have become drought-stressed and vulnerable to high-severity fire after decades of human disturbances and climate warming. This synthesis responds to this need. We present a compilation of existing research across multiple natural resource issues, including disturbance regimes, the legacy effects of past management actions, wildlife habitat, watershed health, restoration concepts from a landscape perspective, and social and policy concerns. We provide...