1. Cropland expansion in the United States produces marginal yields at high costs to wildlife
Recent expansion of croplands in the United States has caused widespread conversion of grasslands and other ecosystems with largely unknown consequences for agricultural production and the environment. Here we assess annual land use change 2008–16 and its impacts on crop yields and wildlife habitat. We find that croplands have expanded at a rate of over one million acres per year, and that 69.5% of new cropland areas produced yields below the national average, with a mean yield deficit of 6.5%. Observed conversion infringed upon high-quality habitat that, relative to unconverted land, had provided over three times higher milkweed stem densities in the Monarch butterfly Midwest summer breeding range and 37% more nesting opportunities per acre for waterfowl in the Prairie Pothole Region of the Northern Great Plains. Our findings demonstrate a pervasive pattern of encroachment into areas that are increasingly marginal for production, but highly significant for wildlife, and suggest that such tradeoffs may be further amplified by future cropland expansion.
Lark, T.J., S.A. Spawn, M. Bougie, and H.K. Gibbs. 2020. Cropland expansion in the United States produces marginal yields at high costs to wildlife. Nature Communications 11:4295. https://doi.org/10.1038/s41467-020-18045-z
2. Cattle, conservation, and carbon in the western Great Plains
Sanderson, J.S., C. Beutler, J.R. Brown, I. Burke, T. Chapman, R.T. Conant, J.D. Derner, M. Easter, S.D. Fuhlendorf, G. Grissom, J.E. Herrick, D. Liptzin, J.A. Morgan, R. Murph, C. Pague, I. Rangwala, D. Ray, R. Rondeau, T. Schulz, and T. Sullivan. 2020. Cattle, conservation, and carbon in the western Great Plains. Journal of Soil and Water Conservation 75:5-12. https://doi.org/10.2489/jswc.75.1.5A
3. Coproducing science to inform working lands: the next frontier in nature conservation
Conservationists are increasingly convinced that coproduction of science enhances its utility in policy, decision-making, and practice. Concomitant is a renewed reliance on privately owned working lands to sustain nature and people. We propose a coupling of these emerging trends as a better recipe for conservation. To illustrate this, we present five elements of coproduction, contrast how they differ from traditional approaches, and describe the role of scientists in successful partnerships. Readers will find coproduction more demanding than the loading dock approach to science delivery but will also find greater rewards, relevance, and impact. Because coproduction is novel and examples of it are rare, we draw on our roles as scientists within the US Department of Agriculture–led Sage Grouse Initiative, North America’s largest effort to conserve the sagebrush ecosystem. As coproduction and working lands evolve, traditional approaches will be replaced in order to more holistically meet the needs of nature and people.
Naugle, D.E., B.W. Allred, M.O. Jones, D. Twidwell, and J.D. Maestas. 2020. Coproducing science to inform working lands: the next frontier in nature conservation. BioScience 70:90-96. https://doi.org/10.1093/biosci/biz144
4. Outcomes in conservation Sage Grouse Initiative
Natural Resources Conservation Service. 2015. Outcomes in conservation Sage Grouse Initiative. U.S. Department of Agriculture. https://www.sagegrouseinitiative.com/wp-content/uploads/2015/08/SGI2.0_Final_Report.pdf
5. Endangered and threatened wildlife and plants; 12-month finding on a petition to list Greater Sage-Grouse (Centrocercus urophasianus) as an endangered or threatened species
US Fish and Wildlife Service (USFWS). 2015. Endangered and threatened wildlife and plants; 12-month finding on a petition to list Greater Sage-Grouse (Centrocercus urophasianus) as an endangered or threatened species. Federal Register 80, 59857–59942. https://www.federalregister.gov/d/2015-24292
6. The last grasslands on Earth.
Scholtz, R and D Twidwell. In Review. The last grasslands on Earth.
7. Natural climate solutions for the United States
Limiting climate warming to <2°C requires increased mitigation efforts, including land stewardship, whose potential in the United States is poorly understood. We quantified the potential of natural climate solutions (NCS)—21 conservation, restoration, and improved land management interventions on natural and agricultural lands—to increase carbon storage and avoid greenhouse gas emissions in the United States. We found a maximum potential of 1.2 (0.9 to 1.6) Pg CO2e year−1, the equivalent of 21% of current net annual emissions of the United States. At current carbon market prices (USD 10 per Mg CO2e), 299 Tg CO2e year−1 could be achieved. NCS would also provide air and water filtration, flood control, soil health, wildlife habitat, and climate resilience benefits.
Fargione, J.E., S. Bassett, T. Boucher, S.D. Bridgham, R.T. Conant, S.C. Cook-Patton, P.W. Ellis, A. Falcucci, J.W. Fourqurean, T. Gopalakrishna, H. Gu, B. Henderson, M.D. Hurteau, K.D. Kroeger, T. Kroeger, T.J. Lark, S.M. Leavitt, G. Lomax, R.I. McDonald, J.P. Megonigal, D.A. Miteva, C.J. Richardson, J. Sanderman, D. Shoch, S.A. Spawn, J.W. Veldman, C.A. Williams, P.B. Woodbury, C. Zganjar, M. Baranski, P. Elias, R.A. Houghton, E. Landis, E. McGlynn, W.H. Schlesinger, J.V. Siikamaki, A.E. Sutton-Grier, and B.W. Griscom. 2018. Natural climate solutions for the United States. Science Advances 4:eaat1869. http://dx.doi.org/10.1126/sciadv.aat1869
8. Great Plains ecosystems: past, present, and future
Little question exists that the main bodies of North American prairie (i.e., the tall-grass, mixed, and shortgrass) are among the most endangered resources on the continent. The purpose of this paper is to provide a past and present biological baseline by which to understand North American prairies and to provide a platform for future conservation. Events both immediate to the end of the Pleistocene and historic suggest that the present grassland conditions are different from those within which most of the grassland organisms evolved. Our analysis suggests that few grassland landscapes remain adequate in area and distribution to sustain diversity sufficient to include biota and ecological drivers native to the landscape. A robust and history-based scenario to conserve Great Plains grasslands is to 1) identify areas large enough to sustain an ecological system with all its biodiversity, 2) reverse significant losses in area of native grasslands, 3) ensure that restoration matches the grassland previously existing at that site, 4) refocus the profession of range management, and 5) establish a more meaningful agency design for grassland and natural resource management.
Samson, F.B., F.L. Knopf, and W.R. Ostlie. 2004. Great Plains ecosystems: past, present, and future. Wildlife Society Bulletin 32:6-15. http://dx.doi.org/10.2193/0091-7648(2004)32[6:gpeppa]2.0.co;2
9. Global effects of land use on local terrestrial biodiversity
Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear—a concern given their importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries’ socioeconomic status.
Newbold, T., L.N. Hudson, S.L.L. Hill, S. Contu, I. Lysenko, R.A. Senior, L. Börger, D.J. Bennett, A. Choimes, B. Collen, J. Day, A. De Palma, S. Díaz, S. Echeverria-Londoño, M.J. Edgar, A. Feldman, M. Garon, M.L.K. Harrison, T. Alhusseini, D.J. Ingram, Y. Itescu, J. Kattge, V. Kemp, L. Kirkpatrick, M. Kleyer, D.L.P. Correia, C.D. Martin, S. Meiri, M. Novosolov, Y. Pan, H.R.P. Phillips, D.W. Purves, A. Robinson, J. Simpson, S.L. Tuck, E. Weiher, H.J. White, R.M. Ewers, G.M. Mace, J.P.W. Scharlemann, and A. Purvis. 2015. Global effects of land use on local terrestrial biodiversity. Nature 520:45-50. http://dx.doi.org/10.1038/nature14324
10. The combined influence of grazing, fire, and herbaceous productivity on tree–grass interactions
Although Juniperus communities are native to most regions of North America, they have proliferated in many areas of the Great Basin and Great Plains that historically supported grasslands, shrublands, and savannas. Explanations for the observed increases in Juniperus dominance, as well as other woody plant communities, are the subject of ongoing debate. The balance between herbaceous and woody vegetation is regulated by complex interactions between climate (e.g., amount and seasonality of rainfall), soils (e.g., soil texture and depth), and disturbance regimes (e.g., fire, gazing, browsing) (Walker 1987; Scholes and Archer 1997; Higgins et al. 2000). Changes in one or more of these factors can potentially elicit a change in the ratio of woody to herbaceous plants. Accordingly, climate change, intensification of grazing, elimination of fire and browsing (Hastings and Turner 1965; Grover and Musick 1990; Archer 1994; Fuhlendorf et al. 1996), atmospheric CO2 enrichment (Idso 1992; Johnson et al. 1993), and nitrogen deposition (Köchy and Wilson 2001) have all been invoked as potential reasons for woody plant proliferation over the past century (see reviews by Archer 1994; Van Auken 2000). However, because these factors are correlative and interact across multiple spatiotemporal scales, it is neither feasible nor realistic to assess their relative importance using traditional, short-term factorial experiments. Field studies based on space-for-time substitutions and comparisons of landscapes with differing management histories have been used to assess long-term changes, but results from such studies are difficult to replicate, interpolate, or extrapolate and do not explicitly test causality. As a result, there is still considerable debate as to the relative importance of grazing, climate, and fire influences on community dynamics in drylands (O’Connor 1995; Fernandez-Gimenez and Allen-Diaz 1999; Illius and O’Connor 1999; Fuhlendorf et al. 2001). Dynamic simulation modeling is an underutilized tool that can be used to evaluate how climate or climate–disturbance interactions potentially affect tree– grass ratios and to test competing hypotheses attempting to account for woody plant increases over the past century.
Fuhlendorf, S.D., S.A. Archer, F. Smeins, D.M. Engle, and C.A. Taylor. 2008. The combined influence of grazing, fire, and herbaceous productivity on tree–grass interactions. Pages 219–238 in O. W. Van Auken, editor. Western North American Juniperus Communities: A Dynamic Vegetation Type. Springer New York, New York, NY. http://dx.doi.org/10.1007/978-0-387-34003-6_12
11. Lesser prairie-chicken avoidance of trees in a grassland landscape
Grasslands are among the most imperiled ecosystems in North America. Reasons that grasslands are threatened include conversion to row-crop agriculture, fragmentation, and changes in fire regimes. The reduction of fire processes in remaining prairies has resulted in tree encroachment and establishment in grasslands, further reducing grassland quantity and quality. Grassland birds have been experiencing precipitous population declines in recent decades, commensurate with landscape changes to grasslands. The lesser prairie-chicken (Tympanuchus pallidicinctus Ridgway) is a declining species of prairie grouse of conservation concern. We used second- and third-order habitat selection metrics to test if female lesser prairie-chickens avoid grasslands where trees were present. Our results indicated that female lesser prairie-chickens selected habitats avoiding the nearest trees by 283 m on average, nearly twice as far as would be expected at random. Lesser prairie-chickens were 40 times more likely to use habitats with tree densities of 0 trees ∙ ha−1 than habitats with 5 trees ∙ ha−1. Probability of use indicated that lesser prairie-chickens were 19 times more likely to use habitats 1000 m from the nearest tree when compared with using habitats 0 m from the nearest tree. Nest survival was not affected at densities < 2 trees ∙ ha−1; however, we could not test if nest survival was affected at greater tree densities as no nests were detected at densities > 2 trees ∙ ha−1. Avoidance of trees could be due to perceived increased predation risk, reduced habitat quality, or a combination of these potentially confounding factors. Preventing further establishment and expansion of trees in landscapes occupied by lesser prairie-chickens could contribute to the continued persistence of the species. Additionally, restoring grasslands through tree removal may facilitate conservation efforts for grassland species such as the lesser prairie-chicken by improving habitat quality and promoting expansion of occupied range.
Lautenbach, J.M., R.T. Plumb, S.G. Robinson, C.A. Hagen, D.A. Haukos, and J.C. Pitman. 2017. Lesser prairie-chicken avoidance of trees in a grassland landscape. Rangeland Ecology and Management 70:78-86. http://dx.doi.org/10.1016/j.rama.2016.07.008
12. Land-use patterns surrounding greater prairie-chicken leks in northwestern minnesota
To better manage wildlife populations, managers must know which combination of land uses creates optimal habitat. We used spatial analysis at a landscape scale to describe land-use patterns and patch characteristics surrounding leks of greater prairie-chicken (Tympanuchus cupido pinnatus L.) in the Agassiz Beach Ridges (ABR) landscape (2,467 km2) in northwest Minnesota. We hypothesized that types and patterns of land use favorable to greater prairie-chickens would be associated positively with lek versus non-lek points, and particularly more stable (traditional) leks. Using a Geographic Information System (GIS), we analyzed land-use proportions and patch characteristics within an 810-ha area (1.6-km radius) surrounding traditional leks, temporary leks, and randomly located non-lek points. We found locations of greater prairie-chicken leks were strongly dependent on land use as revealed by a multivariate analysis of variance (MANOVA; P < 0.001). A discriminant function analysis and univariate analysis of variance (ANOVA) showed that several land-use characteristics were associated most strongly with leks: smaller amounts of residential-farmstead, smaller amounts and smaller patches of forest, and greater amounts of Conservation Reserve Program (CRP) lands. Comparisons between traditional and temporary leks revealed that traditional leks were surrounded by a lesser proportion of forest and cropland than were temporary leks (P < 0.001). Univariate ANOVAs showed that traditional leks also were associated with larger patches of grassland (P < 0.001), and grassland (P = 0.016) and forest patches (P = 0.017) having more irregular shapes. Our study suggests efforts to manage and conserve greater prairie-chicken populations in the Tallgrass Prairie Region should focus on landscape-scale land-use patterns in addition to local habitat characteristics. Landscape-scale efforts could include enlarging grasslands around traditional leks by completing prairie restorations and CRP plantings, while local-scale strategies should seek to improve the quality of habitat in existing and new grassland areas.
Merrill, M.D., K.A. Chapman, K.A. Poiani, and B. Winter. 1999. Land-use patterns surrounding greater prairie-chicken leks in northwestern Minnesota. Journal of Wildlife Management 63:189-198. http://dx.doi.org/10.2307/3802500
13. Tree invasion constrains the influence of herbaceous structure in grassland bird habitats
Trees and other woody plants threaten grassland obligate birds, as well as the biological integrity of grasslands around the world. Bird species associated with grasslands of southern mixed-grass prairie of North America have declined in abundance, whereas species associated with shrub-stage and woodland habitats have increased. Recent increases in the extent of eastern redcedar (Juniperus virginiana) in the southern Great Plains of North America explain some of the change in bird assemblages in landscapes composed of patches of grassland fragmented by cropland and stands of eastern redcedar. In this study, we determined the influence of eastern redcedar, relative to the influence of structural attributes of the herbaceous layer, on bird assemblages within individual patches of grassland habitat. We indexed bird abundance within the breeding season with point counts on grassland patches with varying levels of invasion of eastern redcedar. Canopy cover of eastern redcedar explained a greater proportion of the composition of bird communities in these grasslands than structure of herbaceous vegetation. Species associated with grassland habitats generally declined in abundance, whereas species associated with shrub and woodland habitats increased as cover of eastern redcedar increased. Perhaps more important to conservation ecology, our data indicate that as canopy cover of eastern redcedar increased, variation in abundance of grassland birds decreased, indicating that canopy cover of eastern redcedar may constrain the local influence of herbaceous habitat structure on bird assemblages.
Chapman, R.N., D.M. Engle, R.E. Masters, and D.M. Leslie. 2004. Tree invasion constrains the influence of herbaceous structure in grassland bird habitats. Écoscience 11:55-63. http://dx.doi.org/10.1080/11956860.2004.11682809
14. Eastern redcedar invasion threatens funding for nebraska’s public schools
Lally, D., C. Bielski, B. Schick, C. Westerhold, A. Zahn, C.R. Allen, B. Anderson, D. Twidwell. 2016. Eastern redcedar invasion threatens funding for Nebraska’s public schools. University of Nebraska Extension, BeefWatch. https://newsroom.unl.edu/announce/beef/5577/31325
15. Woody plant encroachment and the sustainability of priority conservation areas
Woody encroachment is a global driver of grassland loss and management to counteract encroachment represents one of the most expensive conservation practices implemented in grasslands. Yet, outcomes of these practices are often unknown at large scales and this constrains practitioner’s ability to advance conservation. Here, we use new monitoring data to evaluate outcomes of grassland conservation on woody encroachment for Nebraska’s State Wildlife Action Plan, a statewide effort that targets management in Biologically Unique Landscapes (BULs) to conserve the state’s natural communities. We tracked woody cover trajectories for BULs and compared BUL trajectories with those in non-priority landscapes (non-BULs) to evaluate statewide and BUL-scale conservation outcomes more than a decade after BUL establishment. Statewide, woody cover increased by 256,653 ha (2.3%) from 2000–2017. Most BULs (71%) experienced unsustainable trends of grassland loss to woody encroachment; however, management appeared to significantly reduce BUL encroachment rates compared to non-BULs. Most BULs with early signs of encroachment lacked control strategies, while only one BUL with moderate levels of encroachment (Loess Canyons) showed evidence of a management-driven stabilization of encroachment. These results identify strategic opportunities for proactive management in grassland conservation and demonstrate how new monitoring technology can support large-scale adaptive management pursuits.
Fogarty, D.T., C.P. Roberts, D.R. Uden, V.M. Donovan, C.R. Allen, D.E. Naugle, M.O. Jones, B.W. Allred, and D. Twidwell. 2020. Woody plant encroachment and the sustainability of priority conservation areas. Sustainability: Science Practice and Policy 12:8321. http://dx.doi.org/10.3390/su12208321
16. A synthesis of the effect of woody vegetation on grassland nesting birds
Sixty-nine articles with references to grassland nesting species associations with woody vegetation were annotated to summarize our current knowledge on the effect of woody vegetation on these species. Bird relationships to woody vegetation were summarized at 4 levels: amount within the grassland patch, perimeter comprised of woodland, distance of a nest or survey from woodland habitat, and the proportion of woodland habitat within the surrounding landscape. Overall, these studies indicate woody vegetation at all levels has a deleterious effect on occurrence, density and/or nesting success of both game and nongame grassland nesting birds. Only 2 grassland nesting species responded positively to a measure of woody vegetation in ≥ 2 studies. Edge effects associated with woody vegetation have been detected in pheasants, ducks, grouse and nongame birds in studies conducted over a broad geographical range (Montana, South Dakota, Minnesota, Missouri, Oklahoma, Wisconsin, Iowa, Manitoba).
Bakker, K.K. 2003. A synthesis of the effect of woody vegetation on grassland nesting birds. Proceedings of the South Dakota Academy of Science 82:119-141.https://sdaos.org/wp-content/uploads/pdfs/2003/2003Vol82.pdf#page=125
17. Multi-scale effects of habitat loss and fragmentation on lesser prairie-chicken populations of the US Southern Great Plains
Large-scale patterns of land use and fragmentation have been associatedwith the decline of many imperiled wildlife populations. Lesserprairie-chickens(Tympanuchus pallidicinctus) are restricted to thesouthernGreat Plains of North America, and their population and range have declined by> 90% over the past 100 years. Our objective was to examine scale-dependentrelationships between landscape structure and change and long-term populationtrends for lesser prairie-chicken populations in the southern Great Plains. Weused a geographic information system (GIS) to quantify landscape composition,pattern and change at multiple scales (extents) for fragmented agriculturallandscapes surrounding 10 lesser prairie-chicken leks. Trend analysis oflong-term population data was used to classify each population and landscape(declined, sustained). We analyzed metrics of landscape structure and changeusing a repeated measures analysis of variance to determine significant effects(α = 0.10) between declining and sustained landscapes across multiplescales. Four metrics of landscape structure and change (landscape change index,percent cropland, increases in tree-dominated cover types, and changes in edgedensity) contained significant interactions between population status andscale,indicating different scaling effects on landscapes with declining and stablepopulations. Any single spatial scale that was evaluated would not have givencomplete results of the influences of landscape structure and change on lesserprairie-chicken populations. The smallest spatial scales (452, 905, and 1,810ha) predicted that changes in edge density and largest patch sizewere the only important variables, while large-scale analysis (7,238ha) suggested that the amount of cropland, increase in trees(mostly Juniperus virginiana), and general landscapechanges were most important. Changes in landscape structure over the pastseveral decades had stronger relationships with dynamics of lesserprairie-chicken populations than current landscape structure. Observed changessuggest that these local populations may be appropriately viewed from ametapopulation perspective and future conservation efforts should evaluateeffects of fragmentation on dispersal, colonization, and extinction patterns.
Fuhlendorf, S.D., A.J.W. Woodward, and D.M. Leslie. 2002. Multi-scale effects of habitat loss and fragmentation on lesser prairie-chicken populations of the US southern Great Plains. Landscape Ecology 17:617-628. http://dx.doi.org/10.1023/A:1021592817039
18. Northern bobwhite response to habitat restoration in eastern Oklahoma
In response to the decline of northern bobwhite (Colinus virginianus; hereafter, bobwhite) in eastern Oklahoma, USA, a cost‐share incentive program for private landowners was initiated to restore early successional habitat. Our objectives were to determine whether the program had an effect on bobwhite occupancy in the restoration areas and evaluate how local‐ and landscape‐level habitat characteristics affect occupancy in both restoration and control areas. We surveyed 14 sample units that received treatment between 2009 and 2011, and 17 sample units that were controls. We used single‐season occupancy models, with year as a dummy variable, to test for an effect of restoration treatment and habitat variables on occupancy. We found no significant treatment effect. Model selection showed that occupancy was best explained by the combination of overstory canopy cover and habitat area at both the local and landscape scales. Moran’s I revealed positive spatial autocorrelation in the 1,000–3,000‐m distance band, indicating that the likelihood of bobwhite occupancy increased with proximity to other populations. We show that creating ≥20 ha of habitat within 1–3 km of existing bobwhite populations increases the chance of restoration being successful.
Crosby, A.D., R.D. Elmore, and D.M. Leslie. 2013. Northern bobwhite response to habitat restoration in eastern Oklahoma: bobwhite habitat restoration. Wildlife Society Bulletin 37:733-740. http://dx.doi.org/10.1002/wsb.351
19. Advancing fire ecology in 21st century rangelands
Fire ecology has a long history of empirical investigation in rangelands. However, the science is inconclusive and incomplete, sparking increasing interest on how to advance the discipline. Here, we introduce a new framework for qualitatively and quantitatively understanding the ranges of variability in fire regimes typical of experimental investigations in rangeland fire science compared with the range of conditions that actually occurred during contemporary social-ecological times. We implement this framework for one of rangelands’ most pyrogenic systems—the Great Plains of North America. We identify four social-ecological fire eras that have epitomized people’s relationship with wildland fire in the Great Plains since the last glacial maxima. These cultural fire eras include the now-extinct coexistence era (indigenous fire use), the suppression era (extermination of wildland fire occurrence), the shadow era (localized prescribed burning groups), and the emerging wildfire era (resulting from wildland fire management failures, continued decoupling of human-fire ignitions, and global change). Our synthesis demonstrates that experimental fire conditions have not explored the types and ranges of variation in fire regime components responsible for shaping rangeland vegetation—now, in the past, or into the future. Instead, scientific investigations have focused largely on controlling and minimizing sources of uncertainty and experimental variation, essentially eliminating ranges of variation that underpin the functioning of fire in modern social-ecological systems. Yet a series of scientific investigations exist that targeted a wider range of variability in fire regime components, leading to major advancements and the rejection of a number of long-standing rules of thumb in rangeland science and management. These include 1) the manipulation of fire return interval, 2) the pyric herbivory experiments, and 3) the extreme fire trials. We discuss the general philosophy shared among these studies, introduce scientific standards needed to avoid common pitfalls, and highlight opportunities to better understand how rangeland pattern and process correspond to critical ranges of variation in the human-fire relationship.
Twidwell, D., C.H. Bielski, R. Scholtz, and S.D. Fuhlendorf. In Press. Advancing fire ecology in 21st century rangelands. Rangeland Ecology and Management. https://doi.org/10.1016/j.rama.2020.01.008
20. Spatial imaging and screening for regime shifts
Screening is a strategy for detecting undesirable change prior to manifestation of symptoms or adverse effects. Although the well-recognized utility of screening makes it commonplace in medicine, it has yet to be implemented in ecosystem management. Ecosystem management is in an era of diagnosis and treatment of undesirable change, and as a result, remains more reactive than proactive and unable to effectively deal with today’s plethora of non-stationary conditions. In this paper, we introduce spatial imaging-based screening to ecology. We link advancements in spatial resilience theory, data, and technological and computational capabilities and power to detect regime shifts (i.e., vegetation state transitions) that are known to be detrimental to human well-being and ecosystem service delivery. With a state-of-the-art landcover dataset and freely available, cloud-based, geospatial computing platform, we screen for spatial signals of the three most iconic vegetation transitions studied in western USA rangelands: (1) erosion and desertification; (2) woody encroachment; and (3) annual exotic grass invasion. For a series of locations that differ in ecological complexity and geographic extent, we answer the following questions: (1) Which regime shift is expected or of greatest concern? (2) Can we detect a signal associated with the expected regime shift? (3) If detected, is the signal transient or persistent over time? (4) If detected and persistent, is the transition signal stationary or non-stationary over time? (5) What other signals do we detect? Our approach reveals a powerful and flexible methodology, whereby professionals can use spatial imaging to verify the occurrence of alternative vegetation regimes, image the spatial boundaries separating regimes, track the magnitude and direction of regime shift signals, differentiate persistent and stationary transition signals that warrant continued screening from more concerning persistent and non-stationary transition signals, and leverage disciplinary strength and resources for more targeted diagnostic testing (e.g., inventory and monitoring) and treatment (e.g., management) of regime shifts. While the rapid screening approach used here can continue to be implemented and refined for rangelands, it has broader implications and can be adapted to other ecological systems to revolutionize the information space needed to better manage critical transitions in nature.
Uden, D.R., D. Twidwell, C.R. Allen, M.O. Jones, D.E. Naugle, J.D. Maestas, and B.W. Allred. 2019. Spatial imaging and screening for regime shifts. Frontiers in Ecology and Evolution 7:407. http://dx.doi.org/10.3389/fevo.2019.00407
21. Grass to grain: probabilistic modeling of agricultural conversion in the North American Great Plains
Conversion of temperate grasslands in the North American Great Plains has long been identified as a threat to native species and systems. Avoiding conversion, particularly to agricultural cover, has been modeled to show benefits for preserving species diversity and connectivity and maintaining ecosystem services provided by grasslands such as avoiding nutrient and sediment runoff. To identify areas of likely conversion, we employed a probabilistic ecoregion-wide model using soil, topography, and climate variables to simulate future conversion. Our results indicated that roughly 60% of the ecoregion is at moderate or higher risk of conversion or has previously been converted. These data can be used to direct grassland conservation efforts and as a metric to assess suitability of future crop expansion. Also, with added information on government subsidies, clean energy mandates, conservation incentives, and other economic data, our model can be used to assess the benefits and disadvantages of such programs and policies.
Olimb, S.K., and B. Robinson. 2019. Grass to grain: probabilistic modeling of agricultural conversion in the North American Great Plains. Ecological indicators 102:237-245. http://dx.doi.org/10.1016/j.ecolind.2019.02.042
22. Plowprint: tracking cumulative cropland expansion to target grassland conservation
Conversion of grassland to cropland has accelerated over the past decade due to high crop prices, government incentives, and a growing global human population. Conversion of grasslands leads to loss of habitat and threatens the ability of the land to provide ecosystem services, such as carbon sequestration, water filtration, and reduced erosion. We developed a method for identifying remaining intact habitat across the Mississippi River Basin–Great Plains area by stacking subsequent years of the Cropland Data Layer (United States) and Annual Crop Inventory (Canada). We call the resulting cumulative plowed lands the “plowprint.” The total size of the plowprint increased by 27,159,278 ha from 2009 to 2013. As of 2013, approximately one-third of the study area had been plowed. We conclude that developing the ability to monitor cumulative change over time will allow disparate agencies and organizations to align their goals, strategies, and activities, and to measure progress in a uniform way.
Gage, A.M., S.K. Olimb, and J. Nelson. 2016. Plowprint: tracking cumulative cropland expansion to target grassland conservation. Great Plains Research 26:107-116. http://dx.doi.org/10.1353/gpr.2016.0019
23. Recent land use change in the western corn belt threatens grasslands and wetlands
In the US Corn Belt, a recent doubling in commodity prices has created incentives for landowners to convert grassland to corn and soybean cropping. Here, we use land cover data from the National Agricultural Statistics Service Cropland Data Layer to assess grassland conversion from 2006 to 2011 in the Western Corn Belt (WCB): five states including North Dakota, South Dakota, Nebraska, Minnesota, and Iowa. Our analysis identifies areas with elevated rates of grass-to-corn/soy conversion (1.0–5.4% annually). Across the WCB, we found a net decline in grass-dominated land cover totaling nearly 530,000 ha. With respect to agronomic attributes of lands undergoing grassland conversion, corn/soy production is expanding onto marginal lands characterized by high erosion risk and vulnerability to drought. Grassland conversion is also concentrated in close proximity to wetlands, posing a threat to waterfowl breeding in the Prairie Pothole Region. Longer-term land cover trends from North Dakota and Iowa indicate that recent grassland conversion represents a persistent shift in land use rather than short-term variability in crop rotation patterns. Our results show that the WCB is rapidly moving down a pathway of increased corn and soybean cultivation. As a result, the window of opportunity for realizing the benefits of a biofuel industry based on perennial bioenergy crops, rather than corn ethanol and soy biodiesel, may be closing in the WCB.
Wright, C.K., and M.C. Wimberly. 2013. Recent land use change in the western corn belt threatens grasslands and wetlands. Proceedings of the National Academy of Sciences 110:4134-4139. https://doi.org/10.1073/pnas.1215404110
24. Decline of the North American avifauna
Species extinctions have defined the global biodiversity crisis, but extinction begins with loss in abundance of individuals that can result in compositional and functional changes of ecosystems. Using multiple and independent monitoring networks, we report population losses across much of the North American avifauna over 48 years, including once-common species and from most biomes. Integration of range-wide population trajectories and size estimates indicates a net loss approaching 3 billion birds, or 29% of 1970 abundance. A continent-wide weather radar network also reveals a similarly steep decline in biomass passage of migrating birds over a recent 10-year period. This loss of bird abundance signals an urgent need to address threats to avert future avifaunal collapse and associated loss of ecosystem integrity, function, and services.
Rosenberg, K.V., A.M. Dokter, P.J. Blancher, J.R. Sauer, A.C. Smith, P.A. Smith, J.C. Stanton, A. Panjabi, L. Helft, M. Parr, and P.P. Marra. 2019. Decline of the North American avifauna. Science:eaaw1313. http://dx.doi.org/10.1126/science.aaw1313
25. The Conservation Reserve Program: 49th Signup Results
Farm Service Agency. 2016. The Conservation Reserve Program: 49th Signup Results. USDA, Washington, DC. https://www.fsa.usda.gov/Assets/USDA-FSA-Public/usdafiles/Conservation/PDF/SU49Book_State_final1.pdf
26. The farm bill and duck production in the prairie pothole region: increasing the benefits
The Food Security Act of 1985 contained provisions that affected wildlife conservation nationwide. Two provisions that most benefited waterfowl populations in the Prairie Pothole Region (PPR) were the Conservation Reserve Program (CRP) and “Swampbuster” (wetland conservation). Permanent cover established under the CRP provides attractive nesting habitat for upland‐nesting ducks that is more secure than other major habitats. Swampbuster has prevented drainage of wetlands vital to breeding duck pairs. In 2007 many CRP contracts will expire. Deliberations will begin in late 2006 regarding the next Farm Bill. The United States Department of Agriculture needs sound biological information and scientific analyses to help establish wildlife priorities in the Farm Bill. We used data from breeding duck population and wetland habitat surveys to develop models for 5 species of upland‐nesting ducks and applied these models to >2.6 million wetlands in a digital database for the PPR in North and South Dakota, USA. We used geographic information systems techniques to identify locations in the PPR where CRP cover would be accessible to the greatest number of nesting hens. We then summarized distribution of current CRP contracts relative to distribution of upland‐breeding ducks. We also used our models to predict change in the breeding duck population (landscape carrying capacity) that might occur if certain wetlands were exempt from the Swampbuster provision. Our analyses showed that 75% of CRP contracts as of July 2005 were in areas accessible to high or medium numbers of breeding ducks and 25% were in areas of low populations. We suggest a method to prioritize CRP extensions and reenrollment of current contracts or target new contracts to maintain or increase duck production. Additionally, our models suggested that if the Swampbuster provision were removed from future Farm Bills and protected wetland were drained, this area of the PPR could experience a 37% decline in the waterfowl populations we studied.
Reynolds, R.E., T.L. Shaffer, C.R. Loesch, and R.R. Cox, Jr. 2006. The farm bill and duck production in the prairie pothole region: increasing the benefits. Wildlife Society Bulletin 34:963-974. http://dx.doi.org/10.2193/0091-7648(2006)34[963:tfbadp]2.0.co;2
27. Conservation Reserve Program (CRP) lands provide ecosystem service benefits that exceed land rental payment costs
Global demand for commodities prompted the expansion of row crop agriculture in the Upper Midwest, USA with unknown consequences for multiple ecosystem services. The Conservation Reserve Program (CRP) was designed to protect these services by paying farmers to retire environmentally sensitive land. Here we assessed whether the benefits provided by CRP’s targeted retirement of agricultural land are equal to or greater in value than the cost of rental payments to farmers. We quantified the benefits of CRP lands for reducing flood damages, improving water quality and air-quality, and contributing to greenhouse gas mitigation in the Indian Creek watershed in Iowa. We found that for all assessed scenarios of CRP implementation, the ecosystem service benefits provided by CRP lands exceed the cost of payments to farmers. Expanding CRP implementation under one of three potential scenarios would require an average per-acre payment of $1311 over the life of a 10-year contract but would generate benefits with a net present value of between $1710 and $6401. This analysis suggests that investment in CRP in Indian Creek, and likely in other watersheds in the Upper Midwest, is justified based upon the value of public and private benefits provided by CRP lands.
Johnson, K.A., B.J. Dalzell, M. Donahue, J. Gourevitch, D.L. Johnson, G.S. Karlovits, B. Keeler, and J.T. Smith. 2016. Conservation Reserve Program (CRP) lands provide ecosystem service benefits that exceed land rental payment costs. Ecosystem Services 18:175-185. https://doi.org/10.1016/j.ecoser.2016.03.004
28. Soil health recovery after grassland reestablishment on cropland: The effects of time and topographic position
The Conservation Reserve Program (CRP) is a U.S. federal land conservation program that incentivizes grassland reestablishment on marginal lands. Although this program has many environmental benefits, two critical questions remain: does reestablishing grasslands via CRP also result in soil health recovery, and what parts of restored fields (i.e., topographic positions) recover the fastest? We hypothesized that soil health will recover over time after converting cropland to CRP grassland and that recovery will be greatest at higher topographic positions. To test this, we sampled 241 midwestern U.S. soils along a grassland chronosequence (0–40 yr, including native grasslands) and at four topographic positions (i.e., a chronotoposequence). Soils were measured for bulk density, maximum water holding capacity (MWHC), soil organic C (SOC), extractable inorganic N, potentially mineralizable C (PMC), and N. Native grasslands had superior soil health compared with cropland and most CRP soils, and even 40 yr since grassland reestablishment was not adequate for full soil health recovery. Topographic position strongly influenced soil health indicators and often masked any CRP effect, especially with MWHC and SOC. However, PMC (a measure of active C) responded most rapidly to CRP and consistently across the landscape and was 26–34% greater 19–40 yr after grassland reestablishment. Reestablishing grasslands through CRP can improve soil health, although topographic position regulates the recovery, with greatest improvements at shoulder slope positions. Patience is needed to observe changes in soil health, even in response to a drastic management change like conversion of cropland to CRP grassland.
De, M., J.A. Riopel, L. J. Cihacek, M. Lawrinenko, R. Baldwin‐Kordick, S.J. Hall, and M.D. McDaniel. 2020. Soil health recovery after grassland reestablishment on cropland: the effects of time and topographic position. Soil Science Society of America Journal 84:568-586. http://dx.doi.org/10.1002/saj2.20007
29. Private land conservation programs scale-up to meet population recovery goals for the most vulnerable grassland birds
Pavlacky D.C., Jr., C.A. Hagen, A.M. Bartuszevige, R. Iovanna, T.L. George, and D.E. Naugle. 2021. Private land conservation programs scale-up to meet population recovery goals for the most vulnerable grassland birds. Conservation Biology
30. Land use decisions after the Conservation Reserve Program: re‐enrollment, reversion, and persistence in the southern Great Plains
The temperate grasslands of North America remain one of the most modified and threatened ecosystems on the planet. In the United States, the conservation of grassland‐dependent wildlife continues to be challenged by the widespread conversion of privately owned grasslands to cropland. Recent analyses indicate that land exiting the Conservation Reserve Program (CRP), the country’s largest private lands conservation program, is a primary source of grassland conversion. In this mixed‐methods study, we employed focus groups and mail surveys to understand the decisions made by landowners in the southern Great Plains as their CRP contracts near expiration and up to 7 years following expiration. We explored both the post‐contract intentions of landowners with fields currently enrolled in CRP and the self‐reported, post‐contract decisions of landowners whose CRP contracts expired between 2011 and 2017. Interest in re‐enrolling in CRP upon contract expiration was high among landowners with current fields; however, over half of landowners with former CRP fields reported being unable to re‐enroll when they tried. We found higher rates of grassland persistence than have been previously reported, but also detected temporal patterns that suggest that cropland reversion is increasingly likely as the time since contract expiration increases. This study highlights the need for increased attention to the barriers that preclude transition into other conservation programs following CRP and more detailed understanding of what drives landowner decision‐making about re‐enrollment and post‐CRP land use. These insights will be critical for increasing the effectiveness of programs for enduring grassland conservation on private lands.
Barnes, J.C., M. Sketch, A.R. Gramza, M.G. Sorice, R. Iovanna, and A.A. Dayer. 2020. Land use decisions after the Conservation Reserve Program: re‐enrollment, reversion, and persistence in the southern Great Plains. Conservation Science and Practice 2. http://dx.doi.org/10.1111/csp2.254
31. Changes in cropland area in the United States and the role of CRP
An understanding of the main drivers of land-use change is critical for policy recommendations that aim to meet the challenge of food and environmental security over the coming decades. Here we show that agricultural policy exerts substantial influence on cropland area in the United States through administration of the Conservation Reserve Program (CRP). Looking at changes in the CRP over time and an understanding of how the program is managed suggest that the government adjusts enrolled acres in response to changing market conditions to achieve supply management objectives and due to budgetary reasons. The projected decrease of 12.8 million acres of CRP from 2007 to 2017 is estimated to decrease corn and soybean prices by 8.9% and 5.4%, while a hypothetical return to 2007 CRP acreage is estimated to increase corn and soybean prices by 12.0% and 7.3%.
Hendricks, N.P., and E. Er. 2018. Changes in cropland area in the United States and the role of CRP. Food policy 75:15-23. http://dx.doi.org/10.1016/j.foodpol.2018.02.001
32. Cropland expansion outpaces agricultural and biofuel policies in the United States
Cultivation of corn and soybeans in the United States reached record high levels following the biofuels boom of the late 2000s. Debate exists about whether the expansion of these crops caused conversion of grasslands and other carbon-rich ecosystems to cropland or instead replaced other crops on existing agricultural land. We tracked crop-specific expansion pathways across the conterminous US and identified the types, amount, and locations of all land converted to and from cropland, 2008–2012. We found that crop expansion resulted in substantial transformation of the landscape, including conversion of long-term unimproved grasslands and land that had not been previously used for agriculture (cropland or pasture) dating back to at least the early 1970s. Corn was the most common crop planted directly on new land, as well as the largest indirect contributor to change through its displacement of other crops. Cropland expansion occurred most rapidly on land that is less suitable for cultivation, raising concerns about adverse environmental and economic costs of conversion. Our results reveal opportunities to increase the efficacy of current federal policy conservation measures by modifying coverage of the 2014 US Farm Bill Sodsaver provision and improving enforcement of the US Renewable Fuels Standard.
Lark, T.J., J.M. Salmon, and H.K. Gibbs. 2015. Cropland expansion outpaces agricultural and biofuel policies in the United States. Environmental Research Letters 10:044003. http://dx.doi.org/10.1088/1748-9326/10/4/044003
33. Increasing durability of voluntary conservation through strategic implementation of the Conservation Reserve Program
Sullins, D.S., M. Bogaerts, B.H.F. Verheijen, D.E. Naugle, T. Griffiths, and C.A. Hagen. In Review. Increasing durability of voluntary conservation through strategic implementation of the Conservation Reserve Program.
34. Thinking like a grassland: challenges and opportunities for biodiversity conservation in the great plains of north america
Fauna of North America’s Great Plains evolved strategies to contend with the region’s extreme spatiotemporal variability in weather and low annual primary productivity. The capacity for large-scale movement (migration and/or nomadism) enables many species, from bison to lark buntings, to track pulses of productivity at broad spatial scales (> 1 000 km2). Furthermore, even sedentary species often rely on metapopulation dynamics over extensive landscapes for long-term population viability. The current complex pattern of land ownership and use of Great Plains grasslands challenges native species conservation. Approaches to managing both public and private grasslands, frequently focused at the scale of individual pastures or ranches, limit opportunities to conserve landscape-scale processes such as fire, animal movement, and metapopulation dynamics. Using the US National Land Cover Database and Cropland Data Layers for 2011−2017, we analyzed land cover patterns for 12 historical grassland and savanna communities (regions) within the US Great Plains. On the basis of the results of these analyses, we highlight the critical contribution of restored grasslands to the future conservation of Great Plains biodiversity, such as those enrolled in the Conservation Reserve Program. Managing disturbance regimes at larger spatial scales will require acknowledging that, where native large herbivores are absent, domestic livestock grazing can function as a central component of Great Plains disturbance regimes if they are able move at large spatial scales and coexist with a diverse array of native flora and fauna. Opportunities to increase the scale of grassland management include 1) spatial prioritization of grassland restoration and reintroduction of grazing and fire, 2) finding creative approaches to increase the spatial scale at which fire and grazing can be applied to address watershed to landscape-scale objectives, and 3) developing partnerships among government agencies, landowners, businesses, and conservation organizations that enhance cross-jurisdiction management and address biodiversity conservation in grassland landscapes, rather than pastures.
Augustine, D., A. Davidson, K. Dickinson, and B. Van Pelt. In Press. Thinking like a grassland: challenges and opportunities for biodiversity conservation in the Great Plains of North America. Rangeland Ecology and Management http://dx.doi.org/10.1016/j.rama.2019.09.001
35. The Lesser Prairie-Chicken range-wide conservation plan
Van Pelt, W.E., S. Kyle, J. Pitman, D. Klute, G. Beauprez, D. Schoeling, A. Janus, and J. B. Haufler. 2013. The lesser prairie-chicken range-wide conservation plan. Western Association of Fish and Wildlife Agencies, Cheyenne, Wyoming, USA. https://wafwa.org/wpdm-package/the-lesser-prairie-chicken-range-wide-conservation-plan/?ind=1611177370571&filename=LPCRWP_finalfor4drule_12092013.pdf&wpdmdl=14683&refresh=60105dea529b51611685354
36. Multiscale occupancy of the Lesser Prairie-Chicken: the role of private lands in conservation of an imperiled bird
Grasslands are one of the most imperiled ecosystems globally, and the Lesser Prairie-Chicken (Tympanuchus pallidicinctus) is an iconic grassland-obligate species with high conservation priority in the USA. Lesser Prairie-Chicken conservation is compounded by its requirement for a spatial hierarchy of heterogeneous habitats, coupled with nearly all (> 95%) of its range being privately owned. The U.S. Department of Agriculture currently offers technical and financial resources that facilitate prairie restoration, e.g., Conservation Reserve Program (CRP), and improve habitat quality and ecosystem services, e.g., Environmental Quality Improvement Program, on private lands. We modeled Lesser Prairie-Chicken occupancy at two scales relative to covariates that described landscape composition and configuration, anthropogenic development, drought-related climatic conditions, and conservation efforts from 2012 to 2016. Large-scale (225 km²) occupancy was most associated with shrubland, grassland patch size, and CRP range-wide. Patterns of small-scale (56.25 km²) occupancy varied regionally, but key covariates included shrubland, grassland, and CRP landcover. These covariate relationships may be useful for identifying conservation practices at different spatial scales and habitat factors that influence Lesser Prairie-Chicken distributions ecoregionally. Notably, CRP-enrolled lands appear to serve as a surrogate for prairie habitat in some ecoregions, especially in conjunction with larger extant patches of native habitat. Although not as influential as CRP at large scales, every 2.25 km² of prescribed grazing increased the odds of site occupancy by 11%. In addition to supported covariates, we found that for every 0.56 km² of industrial development at small scales and 2.25 km² of woodland cover (10%-canopy) at large scales, odds of occupancy decreased by 22% and 13%, respectively. Our results suggest that increased amounts of native grassland and shrubland, and in particular higher levels of CRP enrollment could expand LEPC distribution by as much as 17% (1418–1744 km²). Moreover, our findings illustrate the potential for federal conservation policies to benefit the distribution of an imperiled species.
Hagen, C.A., J.D. Carlisle, F.E. Hornsby, M.E. Houts, L.L. McDonald, and D.C. Pavlacky Jr. 2020. Multiscale occupancy of the lesser prairie-chicken: the role of private lands in conservation of an imperiled bird. Avian Conservation and Ecology 15. http://dx.doi.org/10.5751/ace-01672-150217
37. Effects of emergency haying on duck nesting in conservation reserve program fields, South Dakota
Luttschwager, K.A., K.F. Higgins, and J.A. Jenks. 1994. Effects of emergency haying on duck nesting in Conservation Reserve Program fields, South Dakota. Wildlife Society Bulletin 22:403-408. http://www.jstor.org/stable/3783381
38. Effects of haying on breeding birds in CRP grasslands
The Conservation Reserve Program (CRP) is a voluntary program that is available to agricultural producers to help protect environmentally sensitive or highly erodible land. Management disturbances of CRP grasslands generally are not allowed unless authorized to provide relief to livestock producers during severe drought or a similar natural disaster (i.e., emergency haying and grazing) or to improve the quality and performance of the CRP cover (i.e., managed haying and grazing). Although CRP grasslands may not be hayed or grazed during the primary bird‐nesting season, these disturbances may have short‐term (1 yr after disturbance) and long‐term (≥2 yr after disturbance) effects on grassland bird populations. We assessed the effects of haying on 20 grassland bird species in 483 CRP grasslands in 9 counties of 4 states in the northern Great Plains, USA between 1993 and 2008. We compared breeding bird densities (as determined by total‐area counts) in idle and hayed fields to evaluate changes 1, 2, 3, and 4 years after haying. Haying of CRP grasslands had either positive or negative effects on grassland birds, depending on the species, the county, and the number of years after the initial disturbance. Some species (e.g., horned lark [Eremophila alpestris], bobolink [Dolichonyx oryzivorus]) responded positively after haying, and others (e.g., song sparrow [Melospiza melodia]) responded negatively. The responses of some species changed direction as the fields recovered from haying. For example, densities for common yellowthroat (Geothlypis trichas), sedge wren (Cistothorus platensis), and clay‐colored sparrow (Spizella pallida) declined the first year after haying but increased in the subsequent 3 years. Ten species showed treatment × county interactions, indicating that the effects of haying varied geographically. This long‐term evaluation on the effects of haying on breeding birds provides important information on the strength and direction of changes in bird populations following a disturbance. Results from this study can help guide management of CRP and other grasslands and inform future agricultural programs that address biomass energy production.
Igl, L.D., and D.H. Johnson. 2016. Effects of haying on breeding birds in CRP grasslands: haying effects on grassland birds. Journal of Wildlife Management 80:1189-1204. http://dx.doi.org/10.1002/jwmg.21119
39. Potential carbon dioxide emission reductions from avoided grassland conversion in the northern Great Plains
Protection of lands threatened with conversion to agriculture can reduce carbon emissions. Until recently, most climate change mitigation incentive programs for avoided conversion have focused on forested ecosystems. We applied the Avoided Conversion of Grasslands and Shrublands v.1.0 (ACoGS) methodology now available through the American Carbon Registry to a threatened region of grasslands in the northern Great Plains. For all soil types across 14 counties in North and South Dakota, we used the DAYCENT model calibrated to the study area to quantify the difference in CO2 and N2O emissions under a cropping and a protection scenario, and we used formulas in the ACoGS methodology to calculate CH4 emissions from enteric fermentation under the protection scenario. We mapped the resulting GHG emissions across the entire project area. Emissions averaged 51.6 tCO2e/ha over 20 years, and with a 31% reduction for leakage and uncertainty from the ACoGS methodology, carbon offsets averaged 35.6 tCO2e/ha over 20 years. Protection of 10% of the 2.1 million unprotected ha in the project area with the highest emissions would reduce emissions by 11.7 million tCO2e over 20 years (11% of the total emissions from all unprotected grassland) and avoid a social cost of $430 million worth of CO2 emissions. These results suggest that carbon offsets generated from avoided conversion of grasslands can meaningfully contribute to climate mitigation and grassland conservation objectives.
Ahlering, M., J. Fargione, and W. Parton. 2016. Potential carbon dioxide emission reductions from avoided grassland conversion in the northern Great Plains. Ecosphere 7:e01625. http://dx.doi.org/10.1002/ecs2.1625