Factors Affecting Nest Success and Predator Assemblage of Breeding Birds in Semiarid Grasslands

Woody encroachment has influenced wildlife distributions and, thus, predator-prey dynamics, for many taxa in North American grasslands. In 2015 and 2016, we examined how vegetative characteristics influenced avian nest predator assemblages and nest predation rates in semiarid grasslands of south Texas, where encroachment of woody plant species is common. We monitored 253 nests of 17 bird species and deployed infrared cameras at 107 nest sites within four vegetation types at our study sites. We also used data from a concurrent, multispecies monitoring project within our study area to assess predator activity within these same vegetation types. We divided bird species into four nest types based on nest shape and size (i.e., small, medium, and large cup-shaped nests and exposed nests with little structure). We then used logistic regression to examine relationships between shrub cover, concealment, and distance to edge and the probability of nest success and predation by snakes. We observed a significant decrease in nest success of our medium-sized, cup-shaped nest type when shrub cover increased at the nest site, indicating small increases in shrub cover (≈ 10%) could have substantial impacts on birds using this nest type. Snakes were our primary predator at camera-monitored nests (59%), and snake activity increased by 6.7% with every 10% increase in shrub cover at the nest site. Mesomammalian and large mammalian predators were most active in vegetation types predominated by herbaceous cover, small mammals were most active in vegetation types predominated by woody cover, and snake activity was highly variable. Predator activity did not reflect predator identity at camera-monitored nests, suggesting that potential nest predator activity may not accurately reflect the risk of nest predation. Results of our study will help inform management of bird species using semiarid grasslands affected by woody encroachment and offer recommendations for improved nest success.     

干旱半干旱区草原灌丛化研究进展

干旱半干旱区草原生态系统中原生灌木/木本植物的植株密度、盖度和生物量增加的现象称为草原灌丛化,是全球干旱半干旱区草原面临的重要生态问题,灌丛化研究正成为陆地生态系统全球变化研究的重要领域。引起灌丛化的因素包括过度放牧、草原火、气候变化、大气CO₂浓度升高及生物和非生物环境因子的变化等,灌丛化是多种因素共同作用的结果。灌丛化过程表现为地表景观由草本植物占优势转向灌木植物占优势的植被转变过程,此过程改变了原有植物群落的物种组成和结构,增强了地表景观异质性,打破了原生态系统的光照、热量、水分、养分等的分配格局,灌丛斑块成为了灌丛化草地中水分、养分等相对富集的“肥岛”。目前灌丛化研究主要集中在具有强烈地域性和限制性的定点研究和因子控制实验等方面,未来应更多关注气候变化与灌丛化的相互联系和影响、草地生态系统对灌丛化过程的反馈以及与灌丛化的监测、缓解措施等方面的研究,模型模拟将是今后研究灌丛化发生、发展及灌丛化生态系统演替的重要方法和途径。     

Cattle Grazing Fails to Control Shrub Encroachment in Mediterranean Landscapes

The Common Agricultural Policy supports the use of free-ranging cattle herds to control woody encroachment and fire hazards in Europe. There is, however, little empirical evidence about the effectiveness of extensive grazing to preserve open landscapes in the Mediterranean Basin. In this work, we evaluated the effects of extensive beef cattle grazing on the vegetation structure in a Mediterranean ecosystem using a twofold framework: 1) analyzing temporal changes in the forest, shrub, and grassland cover in areas under different grazing pressures for 16 yr (1993 ? 2009) and 2) studying diet selection to assess the impact of cattle on the local Mediterranean vegetation. Our landscape structure analyses revealed a remarkable change in land cover over the study period. However, woody community dynamics seemed to be more related to natural vegetation succession than to cattle effects. Extensive grazing seemed to preserve grasslands but only at high stocking rates. On the other hand, the diet analyses supported the lack of a role for cattle in encroachment control. Beef cattle diets were based on herbaceous plants (59%) with lower contribution of woody ones (41%). Cattle only showed a significant preference (P < 0.05) for few woody species (Erica multiflora, Olea europaea, Quercus ilex, and Rosmarinus officinalis), mostly at high-density stocking rates. Hence, our results support the idea that extensive cattle grazing alone exerts a negligible effect on shrub encroachment and thus on the risk of fire in the studied Mediterranean area. We urge a redesign of current research to truly integrate extensive cattle grazing as High Nature Value farming in European policies to successfully meet its putative goals, such as shrub encroachment control and wildfire risk prevention.     

Effect of Climoedaphic Heterogeneity on Woody Plant Dominance in the Argentine Caldenal Region

Woody plant encroachment is widespread throughout drylands of the world, but rates and patterns of encroachment at the regional scale can be mediated by soil and climate. Climoedaphic properties may therefore help to explain patterns of woody plant dominance. In the Caldenal region of central Argentina, which is experiencing widespread woody plant encroachment, we used stratified and targeted inventory of vegetation and soils alongside climate data to classify vegetation states and then identify factors indicating resistance to woody plant encroachment. We found that three climoedaphic contexts differed in the degree of woody plant dominance. Sandsheet landforms had the lowest likelihood of a shrub thicket state. Within loamy soils, sites with deep soil carbonates in warmer and wetter climates were less likely to feature a shrub thicket state than sites with shallow carbonates in cooler and drier climates. These contexts serve as a basis for recognizing different ecological sites to assist mapping and prioritization of management interventions in the Caldenal region. Simple inventory-based approaches can be helpful for designing land management recommendations in other ecosystems.     

Coastal Prairie Recovery in Response to Shrub Removal Method and Degree of Shrub Encroachment

Shrub encroachment into grasslands is a worldwide phenomenon with no signs of abating and numerous ecological consequences. In South Texas, honey mesquite (Prosopis glandulosa Torr.) and huisache (Vachellia farnesiana [L.] Wight & Arn.) are two shrubs encroaching into coastal prairies, reducing cover of the dominant native grass, gulf cordgrass (Spartina spartinae [Trin.] Merr. ex Hitchc.), and decreasing habitat for the endangered Aplomado Falcon (Falco femoralis), which requires grasslands or savannas for survival. To determine the best management approach for deterring shrub encroachment and restoring native grasslands, the US Fish and Wildlife Service used several shrub removal techniques within coastal prairies of the Bahía Grande Wetland Complex of the Laguna Atascosa National Wildlife Refuge, a core site for Aplomado Falcon reintroductions. Here, we assess native grass recovery over a 2-yr period in response to these shrub removal methods (mechanical plus prescribed fire and/or herbicide treatments) and degree of shrub encroachment before treatment. In general, areas with high levels of shrub encroachment before treatment had the highest amount of bare ground and lowest grass cover immediately following an initial mechanical treatment; this legacy effect persisted throughout the study irrespective of shrub removal treatment. Regardless of degree of shrub encroachment before treatment, grasses in areas treated with either mechanical or mechanical followed by herbicide methods recovered the slowest, likely due to residual woody material that hindered seed germination. Herbicide treatment following mechanical removal or mechanical removal plus fire effectively hindered shrub regrowth. Overall, mechanical treatment followed by prescribed fire and then herbicide application most effectively promoted grass recovery while hindering shrub regrowth. These findings suggest that grassland recovery following shrub encroachment into South Texas coastal prairies may be promoted through the application of shrub removal methods that combine mechanical, fire, and herbicide treatments.     

Impacts of Mesquite Distribution on Seasonal Space Use of Lesser Prairie-Chickens

Loss of native grasslands by anthropogenic disturbances has reduced availability and connectivity of habitat for many grassland species. A primary threat to contiguous grasslands is the encroachment of woody vegetation, which is spurred by disturbances that take on many forms from energy development, fire suppression, and grazing. These disturbances are exacerbated by natural- and human-driven cycles of changes in climate punctuated by drought and desertification conditions. Encroachment of honey mesquite (Prosopis glandulosa) into the prairies of southeastern New Mexico has potentially limited habitat for numerous grassland species, including lesser prairie-chickens (Tympanuchus pallidicinctus). To determine the magnitude of impacts of distribution of mesquite and how lesser prairie-chickens respond to mesquite presence on the landscape in southeastern New Mexico, we evaluated seasonal space use of lesser prairie-chickens in the breeding and nonbreeding seasons. We derived several remotely sensed spatial metrics to characterize the distribution of mesquite. We then used these data to create population-level resource utilization functions and predict intensity of use of lesser prairie-chickens across our study area. Home ranges were smaller in the breeding season compared with the nonbreeding season; however, habitat use was similar across seasons. During both seasons, lesser prairie-chickens used areas closer to leks and largely avoided areas with mesquite. Relative to the breeding season, during the nonbreeding season habitat use suggested a marginal increase in mesquite within areas of low intensity of use, yet aversion to mesquite was strong in areas of medium to high intensity of use. To our knowledge, our study is the first to demonstrate a negative behavioral response by lesser prairie-chickens to woody encroachment in native grasslands. To mitigate one of the possible limiting factors for lesser prairie-chickens, we suggest future conservation strategies be employed by land managers to reduce mesquite abundance in the southern portion of their current range.     

草地灌丛化成因及其对生态系统的影响研究进展

由于气候变化和人类活动的影响,草地生态系统正经历着剧烈变化,全球草地广泛发生了原生灌木或乔木的密度、盖度和生物量增加的现象。从草地灌丛化的特征及分布、形成机制和对草地生态系统的影响等三方面进行了阐述。放牧、气候变化等诸多因素驱动了草地灌丛化的发生,草地灌丛化过程不但改变了草地生态系统的生物多样性和外貌,而且改变了其结构和功能。灌丛营造了小气候环境,改变了种间关系,调节了土壤营养和物质循环。未来应结合遥感技术对灌丛化发生的面积进行估算,确定灌丛化驱动因素,并准确评价灌丛化草地的结构、功能和服务。     

Determinants of the occurrence of a native encroacher species,Pechuelloeschea leubnitziae (wild sage), in the eastern Okavango Delta,Botswana

Although indigenous to southern Africa, Pechuel-loeschea leubnitziae is considered a problematic weed as it forms dense monotypic stands in the grasslands and woodlands of the Okavango Delta, Botswana, and is associated with veld degradation and a dominance of shade-tolerant, poor-quality grass species. Generalised linear modelling was used to determine the effect of the following environmental conditions on the likelihood of occurrence of P. leubnitziae: type of land use, vegetation type, burning history, total woody species density, soil pH and soil texture. There was no difference in P. leubnitziae presence under wildlife, large livestock and small livestock land use (p = 0.227). Only vegetation type (p<0.001) and total woody species density (p<0.001) significantly affected P. leubnitziae occurrence, with the species being rare in dense mopane woodlands and most likely to occur in mixed thornveld and mixed broadleaf woodland, although this likelihood decreased with increasing total woody species density. A single burn had no effect on P. leubnitziae occurrence, but repeated burning should be investigated as a means to reduce the vigour and recoppicing success of P. leubnitziae.     

Livestock Grazing Impacts on Herbage and Shrub Dynamics in a Mediterranean Natural Park

Shrub encroachment can be explained by the abandonment of extensive livestock farming and changes to land use, and it is a common problem in the Mediterranean mountain pastures of Europe, with direct effects on biodiversity and landscape quality. In this paper, the effects of livestock exclusion vs. grazing on the dynamics of shrub and herbaceous vegetation were analyzed in a Spanish natural park located in a dry Mediterranean mountain area over a 5-yr period. Twelve 10 × 10 m exclosures were set up in six representative pasture areas of the park (with two replicates per location). Each year, the shrub number, volume, and biomass were measured in April, and the herbage height, biomass, and quality were measured in April and December (which represent the start and end of the vegetative growth season). A sustained increase of the shrub population and individual biomass was observed throughout the study, which was reflected in total shrub biomass per ha. Growth was greater in nongrazed exclosures (2 563 kg dry matter [DM] · ha^?1 · yr^?1), but it also happened in the grazed control areas (1 173 kg DM · ha^?1 · yr^?1), with different patterns depending on the location and shrub species. Herbage biomass did not change when grazing was maintained, but it did increase in places where grazing was excluded (291 kg DM · ha^?1 · yr^?1), mostly as a consequence of the accumulation of dead material, with a concomitant reduction in herbage quality. It was concluded that at the current stocking rates and management regimes, grazing alone is not enough to prevent the intense dynamics of shrub encroachment, and further reductions in grazing pressure should be avoided.     

贵州威宁喀斯特山区野生饲用植物资源构成分析

通过资料查阅、野外调查、农户访谈及专家咨询,建立贵州威宁喀斯特山区野生饲用植物数据库,分析该区野生饲用植物的科、属和种构成;依据家畜对不同饲用植物的采食性差异,将该区野生饲用植物划分为优、良、中和劣4级,并对其饲用特性及家畜配置进行分析。结果表明,威宁喀斯特山区有野生饲用植物55科227属384种,草本和木本分别占总饲用植物种类的76%和24%;优势科为禾本科、豆科、菊科、蔷薇科和莎草科等10科,其中,禾本科、豆科和莎草科中的优良饲用植物多,具较高饲用价值;木本饲用植物主要为豆科（26种）和蔷薇科（23种）。综合分析认为,威宁喀斯特山区具有特殊生物活性物质的饲用灌木,可作为家畜冬季补饲料组分和生物保健药添加剂,该区草山草坡宜不同类型家畜混合放牧利用,中等饲用价值饲草可作冬季补饲料、天然草地利用与栽培草地建设并重。     

Root Biomass and Distribution Patterns in a Semi-Arid Mesquite Savanna: Responses to Long-Term Rainfall Manipulation

Expansion of woody plants in North American grasslands and savannas is facilitated in part by root system adaptation to climatic extremes. Climatic extremes are predicted to become more common with global climate change and, as such, may accelerate woody expansion and/or infilling rates. We quantified root biomass and distribution patterns of the invasive woody legume, honey mesquite (Prosopis glandulosa), and associated grasses following a long-term rainfall manipulation experiment in a mixed grass savanna in the southern Great Plains (United States). Root systems of mature trees were containerized with vertical barriers installed to a depth of 270 cm, and soil moisture was manipulated with irrigation (Irrigated) or rainout shelters (Rainout). Other treatments included containerized, precipitation-only (Control) and noncontainerized, precipitation-only (Natural) trees. After 4 yr of treatment, soil cores to 270 cm depth were obtained, and mesquite root length density (RLD) and root mass, and grass root mass were quantified. Mesquite in the Rainout treatment increased coarse-root ( &spigt; 2 mm diameter) RLD and root mass at soil depths between 90 cm and 270 cm. In contrast, mesquite in the Irrigated treatment increased fine-root ( &spilt; 2 mm diameter) RLD and root mass between 30 cm and 270 cm depths, but did not increase total root mass (fine + coarse) compared to the Control. Mesquite root-to-shoot mass ratio was 2.8 to 4.6 times greater in Rainout than the other treatments. Leaf water stress was greatest in the Rainout treatment in the first year, but not in subsequent years, possibly the result of increased root growth. Leaf water use efficiency was lowest in the Irrigated treatment. The increase in coarse root growth during extended drought substantially increased mesquite belowground biomass and suggests an important mechanism by which woody plant encroachment into grasslands may alter below ground carbon stocks under climate change scenarios predicted for this region.     

Tallgrass Prairie Plant Community Dynamics Along a Canopy Cover Gradient of Eastern Redcedar (Juniperus virginiana L.)

North American grasslands make up less than 75% of their historic pre-European settlement area, and they continue to be converted to woodlands by woody plant encroachment. Conversion of grassland to woodland alters nutrient cycling, water use, and light penetration, which drives herbaceous plant community dynamics. Because studies examining this relationship among Juniperus species are limited largely to individual trees, we designed a study to examine the relationship between stand-level canopy cover of eastern redcedar (Juniperus virginiana L.) and the herbaceous plant community. We documented herbaceous plant species composition, abundance, and biomass within a North American tallgrass prairie invaded by eastern redcedar in which canopy cover of eastern redcedar ranged from 0% to 80%. Herbaceous species richness declined as a function of increased canopy cover of eastern redcedar and subsequent loss of open space, but this decrease in species richness closely followed a species–area model. Moreover, composition of C₃ and C₄ grasses and forbs did not change with increasing canopy cover. Herbaceous biomass, which declined with increasing canopy cover, varied most within those plots with intermediate canopy cover. While we found that species richness and biomass declined as canopy cover increased, the decline followed a species–area relationship and was without abrupt change typical of ecological thresholds. We recommend additional research with removal of eastern redcedar trees over a range of canopy cover to assess restoration potential along the encroachment gradient.     

Assessment of Juniper Encroachment With The Use of Satellite Imagery and Geospatial Data

Juniper encroachment into otherwise treeless shrub lands and grasslands is one of the most pronounced environmental changes observed in rangelands of western North America in recent decades. Most studies on juniper change are conducted over small areas, although encroachment is occurring throughout regions. Whether changes in juniper cover can be assessed over large areas with the use of long-term satellite data is an important methodological question. A fundamental challenge in using satellite imagery to determine tree abundance in rangelands is that a mix of trees, sagebrush, and herbaceous cover types can occur within a given image pixel. Our objective was to determine if spectral mixture analysis could be used to estimate changes in Rocky Mountain juniper (Juniperus scopulorum Sarg) and Utah juniper (Juniperus osteosperma [Torr.] Little) cover over 20 yr and 20000 ha in southeast Idaho with the use of Landsat imagery. We also examined the spatial patterns and variation of encroachment within our study area using Geographic Information Systems–based data sets of grazing use, land-cover types, and topography. Juniper cover determined from 15-cm-resolution digital aerial orthophotography was used to train and validate juniper presence/absence classification in 1985 and 2005 Landsat images. The two classified images were then compared to detect changes in juniper cover. The estimated rate of juniper encroachment over our study area was 22–30% between 1985 and 2005, consistent with previous ground-based studies. Moran’s I analysis indicated that juniper encroachment pattern was spatially random rather than clustered or uniform. Juniper encroachment was significantly greater in grazed areas (P = 0.02), and in particular in grazed shrub land cover type (P = 0.06), compared to ungrazed areas. Juniper encroachment was also greater on intermediate slopes (10–35% slopes) compared to steeper or flatter terrain, and encroachment was somewhat less on north-facing (P = 0.03) and more on west-facing (P = 0.02) slopes compared to other aspects.     

The livestock revolution--a global veterinary mission

Increasing population, urbanisation and disposable incomes in developing countries are fuelling a strong growth in demand for animal food products, which in turn will have a strong impact on the location and organisation of global livestock production. Changes in the latter will in turn strongly impinge on animal and human health, the livelihoods of the poor and the environment. The consequences of these trends, termed the 'livestock revolution', are expected to dramatically change the face of animal agriculture in coming decades, including a major increase in the developing countries' share in world livestock production and consumption; a gradual substitution of cereals and other basic foods with meat and milk in the developing countries' diets; a change from multiple production objectives to more specialised intensive meat, milk and egg production within an integrated global food and feed market; a shift to more industrial production and processing; rising use of cereal-based animal feeds; and greater stress on fragile extensive pastoral areas and more pressure on land in areas with very high population densities and close to urban centres. Henning Steinfeld, an agricultural economist from the Food and Agriculture Organization of the United Nations, reviews here trends associated with the 'Livestock Revolution' and predicted implications for animal health. The presentation was given in a plenary session at the 19th International Conference of the World Association for the Advancement of Veterinary Parasitology (WAAVP) held in New Orleans, Louisiana, USA during 10-14 August 2003.     

当前国际草田耕作面临的威胁及采取对策

草田是人类和动物等的食物资源和栖息环境,具有涵养水源、保护生态多样性、减缓气候变化和维持地区可持续发展等作用。目前气候变化、人口增加、水资源和能源资源短缺等对国际草田资源带来严重威胁。为了提高土地生产力,养活不断增加的人口,近几十年大部分国家将半自然状态草地转变农耕地,农耕地管理引起动生物多样性降低和植物群落栖息环境碎片化、退化和消失等。如果国际草田实施粮草轮作、粮草畜协同发展、科学放牧和饲养管理、粮草同等种植优惠政策等,不仅可以提高土地生产力,而且有利于保护生态环境和人类生存可持续发展。     

Plant Community Response Following Removal of Juniperus virginiana from Tallgrass Prairie: Testing for Restoration Limitations

Woody plant encroachment in natural grasslands is a widely documented global phenomenon that alters ecosystem dynamics by altering historic vegetation composition and suppressing herbaceous productivity. Abundant woody plants often suppress native plants sufficiently to establish successional thresholds difficult to reverse without species augmentation. Juniper (Juniperus virginiana L.) is expanding in North American tallgrass prairie, but it is currently unknown if encroachment creates successional restrictions that limit restoration potential. We selected 16 50×50-m sites with juniper canopy cover ranging from zero to approximately 75% in tallgrass prairie near Stillwater, Oklahoma, USA. Juniper trees were removed from 7 of the sites along the gradient of juniper canopy cover. Canopy cover of plant species and herbaceous plant productivity were estimated at each site 1 year before and 1, 2, and 5 years after tree removal. Before trees were removed, plant species richness and productivity declined as juniper canopy cover increased, and plant community composition dissimilarity of reference sites increased as juniper canopy cover increased. These relationships remained consistent on all non-removal sites throughout the study. The first year after juniper removal, species richness increased on all removal sites compared to intact sites and productivity on removal sites increased two years after removal. Plant community dissimilarity between reference sites and juniper removal sites remained relatively high (30–60%) the first two years after tree removal on all removal sites, but dissimilarity was about 22% 5 years after juniper removal. Within 5 years, removal sites were comparable to reference plant communities. Grassland restoration frequently requires species manipulation and additional seeding, particularly when overcoming successional limitations. Juniper encroachment into tallgrass prairie alters plant community species composition and productivity. However, in our study, juniper associated succession limitations were not apparent, and complete autogenic restoration was achieved within 5 years without seeding or species manipulation.     

Cool-Season Floodplain Meadow Responses to Shrub Encroachment in Alberta

This study evaluated the impact of shrub encroachment within cool-season floodplain meadows in a portion of the Rocky Mountain Forest Reserve in southwestern Alberta, where nearly half of open grasslands have been lost since 1958. Sample transects situated in meadows, known formerly to be in open grassland, were assessed in 2001 (n = 21) and 2002 (n = 33) in areas ranging from 0% to 92% shrub cover. Shrub cover, density, and height were correlated to understory parameters, including herbaceous production, bunchgrass cover and density, and species richness and diversity. Additional data on soil horizon depths were obtained. Analysis was conducted using regression to assess empirical relationships between understory or soil characteristics and the overstory. Stronger empirical relationships (i.e., greater R²) were found in 2002, coincident with larger sample sizes and greater rainfall. Among independent overstory variables, aggregate shrub cover for all species accounted for the greatest variation in understory characteristics. Significant (P < 0.01) negative nonlinear relationships were observed between shrub cover and herbage production, with the latter declining from 6 629 kg · ha^–1 in meadows containing less than 12% shrub cover, to 2 797 kg · ha^–1 in areas where shrub cover exceeded 35%. Negative linear trends were found (P < 0.01) for bunchgrass density and cover in relation to increasing shrub abundance in 2002. Understory diversity increased with shrub abundance, peaking at 64% shrub cover in 2002. Meadows with low and high shrub cover also coincided with thicker Ah and litter, fibric, and humic soil layer (LFH) horizons, respectively. Collectively, these results indicate shrub encroachment is threatening the sustainability of native bunchgrass communities and reducing forage availability. Meadow conservation in this area will require proactive management to protect or restore open grasslands.     

Mixed livestock grazing in diverse temperate and semi-arid environments

The need for an annual increase of 2% in global food production demands knowledge on how best to use natural grazing land resources. Taken with the requirement to protect resources, this need creates conflicting demands on grazing land management. Concerns for product quality, uniformity and continuity and for animal welfare will increasingly drive production processes. In this paper, the potential of mixed grazing for higher output of quality animal products, within these constraints, is assessed under both temperate and semi-arid conditions. Complementary behavioural patterns between domestic livestock types, particularly in their dietary selection, appear to be the primary basis for development of improved grazing ecosystems. Many of these processes operate at the landscape scale. In addition to increasing animal output, mixed grazing can be used to modify the vegetation. This is of particular importance for manipulating woody species cover in semi-arid areas and hence for improvement of range condition. For rural development, identification with the system and confidence in the purveyor sets the basis for success.     

A Hierarchical Perspective to Woody Plant Encroachment for Conservation of Prairie-Chickens

Encroachment of Great Plains grasslands by fire-sensitive woody plants is a large-scale, regional process that fragments grassland landscapes. Using prairie grouse (Tympanuchus spp.) of conservation concern, we apply hierarchy theory to demonstrate how regional processes constrain lower-level processes and reduce the success of local management. For example, fire and grazing management may be locally important to conservation, but the application of fire and grazing disturbances rarely cause irreversible fragmentation of grasslands in the Great Plains. These disturbance processes cause short-term alterations in vegetation conditions that can be positive or negative, but from a long-term perspective fire maintains large tracts of continuous rangelands by limiting woody plant encroachment. Conservation efforts for prairie grouse should be focused on landscape processes that contribute to landscape fragmentation, such as increased dominance of trees or conversion to other land uses. In fact, reliance on local management (e.g., maintaining vegetation structure) to alter prairie grouse vital rates is less important to grouse population persistence given contemporary landscape level changes. Changing grass height, litter depth, or increasing the cover of forbs may impact a few remaining prairie-chickens, but it will not create useable space at a scale relevant to the historic conditions that existed before land conversion and fire suppression.