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Grasslands in the northern Great Plains are important ecosystems that support local economies, tribal communities, livestock grazing, diverse plant and animal communities, and large-scale migrations of big game ungulates, grassland birds, and waterfowl. Climate change and variability impact how people and animals live on and interact with grasslands, and can bring more frequent droughts, fires, or new plant species that make managing these landscapes challenging. Understanding how climate change and variability will impact grassland ecosystems and their management in the 21st century first requires a synthesis of what is known across all of these scales and a gap analysis to identify key areas of focus for future...
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Prairies were once widespread across North America, but are now one of the most endangered and least protected ecosystems in the world. Agriculture and residential development have reduced once extensive prairies into a patchwork of remnant prairies and “surrogate” grasslands (e.g., hayfields, planted pastures). Grassland ecosystems and many grassland-dependent birds are also particularly vulnerable to rapid shifts in climate and associated changes in drought and extreme weather. The Central Flyway is a vast bird migration route that comprises more than half of the continental U.S., and extends from Central America to Canada, and harbors the greatest diversity of grassland birds in North America. Throughout this...
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...
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The sagebrush ecosystem is home to diverse wildlife, including big-game and Greater sage-grouse. Historic and contemporary land-uses, large wildfires, exotic plant invasion, and woodland expansion all represent threats to this multiple-use landscape. Efforts of federal and state agencies and private landowners across the landscape are focused on restoration and maintenance of conditions that support wildlife, livestock, energy development, and many other uses. However, this semi-arid landscape presents challenges for management due to highly variable patterns in growing conditions that lead to differences in plant composition, fuel accumulation, and vegetation recovery. Much of this variability is created by soil...
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...
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Pinyon pine woodlands are among the most widespread and iconic vegetation types in the western United States and support recreation, resource extraction, grazing, and cultural enrichment. However, severe drought conditions have recently caused dramatic mortality of pinyon pines, creating concern about the long-term impact of increasing aridity on the viability of pinyon woodlands. Ecological transformations, or regime shifts, are rapid reorganizations of an ecosystem’s species composition, governing processes, and functions. The goal of this project is to investigate ecological transformation across the Western U.S, characterize the environmental drivers of these changes in vegetation, and apply those insights...
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Big sagebrush plant communities are important and widespread in western North America and are crucial for meeting long-term conservation goals for greater sage-grouse and other wildlife of conservation concern. Yet wildfire is increasing in the West, turning biodiverse, shrub-based ecosystems dominated by sagebrush into grasslands containing invasive species such as cheatgrass and less overall plant and animal diversity. These transformations negatively impact people and ecosystems by reducing habitat quality for wildlife and the aesthetic value of the landscape. Understanding how sagebrush communities are already responding and will continue to respond to changes in wildfire, invasive species, and climate is...
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Forested areas in the Western U.S. that are impacted by disturbances such as fire and drought have increased in recent decades. This trend is likely to continue, with the increase in frequency and extent of wildfire activity being especially concerning. Resource managers need reliable scientific information to better understand wildfire occurrence, which can vary substantially across landscapes and throughout time. However, few scientific models capture this variability, and projections of future potential changes in fire occurrence can include some uncertainty. This uncertainty can limit our ability to anticipate potential wildfire impacts on society and ecological systems. Another method to help managers prepare...
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...
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...
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Over the last half-century, grassland bird populations have declined far more than any other bird group in North America. This is because native grasslands were largely replaced with croplands, and many remaining prairies are degraded. Land managers and conservation organizations are racing to preserve and restore these ecosystems to stem further loss of grassland birds. Given limited resources, bird habitat models are needed to help managers prioritize where conservation efforts will be most effective. In addition to habitat loss and degradation from land use change, altered fire regimes, and woody encroachment, increasing greenhouse gas emissions will likely change temperatures and rainfall patterns across North...
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Prescribed burning – planned, controlled fires conducted under weather and fuel conditions designed for safety and effectiveness – is a common practice used to maintain and restore native prairies in the Northern Great Plains. However, climate change will affect the number of days in a year, and when, suitable conditions for prescribed fires occur. For instance, warmer temperatures may shift these “good prescribed-fire days” earlier in the spring and later in the fall, but uncertainty about future climate makes it hard to predict how large shifts will be and if the number of good fire days each year will generally increase or decrease. Further, it’s hard to know whether prescribed fires will continue to achieve...
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Invasions of exotic annual grasses (EAGs like cheatgrass have caused major losses of native shrubs and grasses in western U.S. rangelands. They also decrease the productivity and carbon storage in these ecosystems, which is expected to create dryer soils that may cause further losses in plant productivity. This cycle is the hallmark of desertification – or, fertile lands turning into deserts. Management actions that target EAGs are one of the most widespread land management actions taken in Western U.S. rangelands, but it is unclear which specific actions can simultaneously enhance drought resilience of native plant communities and increase carbon sequestration and storage. This project aims to identify the restoration...
Scientists gathered at a workshop in Cambridge, Mass., last June to identify opportunities and challenges associated with integrating multiscale, multiplatform streams of data to produce higher-level phenological data products (e.g., models) and applications at a variety of spatial and temporal resolutions.
Vegetation phenology controls the seasonality of many ecosystem processes, as well as numerous biosphere-atmosphere feedbacks. Phenology is also highly sensitive to climate change and variability. Here we present a series of datasets, together consisting of almost 750 years of observations, characterizing vegetation phenology in diverse ecosystems across North America. Our data are derived from conventional, visible-wavelength, automated digital camera imagery collected through the PhenoCam network. For each archived image, we extracted RGB (red, green, blue) colour channel information, with means and other statistics calculated across a region-of-interest (ROI) delineating a specific vegetation type. From the high-frequency...
map background search result map search result map Big Sagebrush Response to Wildfire and Invasive Grasses in the 21st Century Mapping the Risk of Ecological Transformation Across Pinyon Woodlands and the U.S. West Understanding Local Resistance and Resilience to Future Habitat Change in the Sagebrush Ecosystem Synthesis of Climate Impacts and Adaptation on Grassland Ecosystems in the Northern Great Plains Strategies for Reducing the Vulnerability of Grassland Birds to Climate Change within the Central Flyway Drought and Disturbances as Drivers of Long-Term Ecological Transformation and Risk Climate Effects on Prescribed Fire Implementation and Efficacy in Northern Mixed-Grass Prairie What Will Grassland Bird Communities Look Like Under a Changing Climate? Assessing the Impacts of Rangeland Restoration on Carbon Sequestration and Co-Benefits for Drought Resilience in the Sagebrush Steppe and Mixed Grass Prairie Assessing the Impacts of Rangeland Restoration on Carbon Sequestration and Co-Benefits for Drought Resilience in the Sagebrush Steppe and Mixed Grass Prairie Climate Effects on Prescribed Fire Implementation and Efficacy in Northern Mixed-Grass Prairie Synthesis of Climate Impacts and Adaptation on Grassland Ecosystems in the Northern Great Plains Drought and Disturbances as Drivers of Long-Term Ecological Transformation and Risk What Will Grassland Bird Communities Look Like Under a Changing Climate? Big Sagebrush Response to Wildfire and Invasive Grasses in the 21st Century Understanding Local Resistance and Resilience to Future Habitat Change in the Sagebrush Ecosystem Strategies for Reducing the Vulnerability of Grassland Birds to Climate Change within the Central Flyway Mapping the Risk of Ecological Transformation Across Pinyon Woodlands and the U.S. West