Eastern Grasslands Research Articles

Geographical division of terrestrial mammals in China based on species composition characteristics

China has complex natural conditions and is rich in biodiversity. Based on the geographical distribution and species composition of terrestrial mammals, we explored the characteristics and geographic partitioning of mammal populations in different regions of China. We used a clustering algorithm, combined with the spatial distribution data and taxonomic characteristics of mammals, to geographically partition the terrestrial mammals in China. We found 10 zoogeographic regions of terrestrial mammals in China: Northeast region, North China region, Eastern grassland region, Western region, Northwest region, Qiangtang plateau region, Eastern Qinghai-Tibet Plateau region, Himalayan region, South China region, and Taiwan-Hainan region. We found a new geographical zoning pattern for terrestrial mammals in China, examined the variability and characteristics of species composition among different regions, and quantified the association between species distribution and environmental factors. We proposed a method of incorporating taxonomic information into cluster analysis, which provided a new idea for zoogeographic region studies, a new perspective for understanding species diversity, and a scientific basis for animal conservation and habitat planning.

Spatial-temporal variations of vegetation coverage and its driving force in Inner Mongolia grassland, China

Inner Mongolia grassland is rich in natural vegetation and mineral resources. Based on Landsat5/7/8 NDVI data, we used pixel binary model to invert vegetation coverage of Inner Mongolia grassland area, investigated the stability, spatial distribution, and future evolution trend of vegetation coverage by using Sen+MK and Hurst index, and analyzed the driving factors of the spatial differentiation of vegetation coverage by the optimal parameters-based geographical detector. The results showed that vegetation coverage of Inner Mongolia grassland showed an increasing trend from 2006 to 2020, and the overall spatial pattern was high in the east and low in the west, mainly with great fluctuation. The regions with slight or obvious improvement characteristics (64.8%) were much more than those with slight or severe degradation characteristics (23.2%). Compared with that in the past 15 years, the proportion of degraded vegetation in the future is expected to increase to 36.6%. The central part of Xilin Gol League and Wulanqab in the central grassland area, the western part of Hulunbuir and Erdos in the eastern grassland area, and Wuhai in the western grassland area were at the risk of degradation, which should be paid more attention. Precipitation was the dominant factor of spatial differentiation in Inner Mongolia grassland, while soil type, land use, and air temperature had the most significant synergistic effect.

Locating potential historical fire‐maintained grasslands of the eastern United States based on topography and wind speed

AbstractHistorically, grasslands with limited tree presence were embedded in a matrix of predominantly open oak and pine forests in the eastern United States. These open ecosystems mostly have been lost to other land uses, particularly agriculture, and also to closed forests under fire exclusion because frequent surface fire prevents tree encroachment. We located the potential extent of eastern fire‐maintained grasslands by applying the random forests and C5.0 classifiers to determine the relationship between mapped areas of historical grasslands and topography and wind speed, which are proxies for surface fire frequency. A generalized ruleset was that fire‐maintained grasslands occurred at roughness values of less than 95, or flatter sites, and wind speeds ≥3.4 m s−1, which created large fire compartments. Potential grasslands covered 27 million ha, or 14% of the 200 million ha of the eastern United States, although these fire‐maintained locations also may have been savannas or open woodlands historically. Currently, potential grassland locations are 40% crops, 25% pasture, 18% forests, and 13% developed land, with about 1.5% each of herbaceous upland vegetation, herbaceous wetlands, and shrublands. According to historical accounts, fire‐maintained grasslands generally transitioned to dense young tree growth within a 20‐year interval after fire exclusion; in Kentucky, the transition transpired during the periods 1790–1810 or 1810–1830, but dates vary with Euro‐American settlement time. Finding the forgotten grasslands of the eastern United States, with this mechanistic approach to estimate fire disturbance, is an important first step for recovering and managing eastern grassland biodiversity.

Calibration of disk pasture meter to estimate a fire fuel load (aboveground plant biomass) for fire management in the northeastern steppe of Mongolia

Grassland fires are the most common disturbance in Mongolia's east. Fire risk management in Mongolia's eastern grasslands should include fuel load estimates (aboveground plant biomass) to prevent fire damage. The disc pasture meter (DPM) is a common, rapid, and nondestructive method for estimating aboveground plant biomass in grasslands. Calibration is needed for the DPM application in a given area due to regional variations in climate and plant diversity, as well as site-specific environmental factors. We calibrated a DPM for Mongolia's north-eastern grasslands bordering Russia, classified as a very high-risk region for grassland fire. The calibration was carried out at twelve different sites, and double sampling (DPM reading and plant biomass harvesting) was done at 108 points. The mean of the total dry plant biomass of the sites was 11.27 centner ha-1 (±1.93 SE). The sites differed in total dry plant biomass and its composition. It indicates that the sites are needed different fire managements. Although we developed three linear regression models for DPM readings (100, 200, and 300) to estimate an optimal sampling effort, the model with 300 DPM models had the highest determination coefficient (0.82). Therefore, we suggest the model (y=3.18x+3.1) with the 300 DPM readings for further application.

Precipitation dominants synergies and trade-offs among ecosystem services across the Qinghai-Tibet Plateau

Understanding synergies and trade-offs of ecosystem services (ESs), finding influencing factors related to these ESs, and determining how these factors regulate spatiotemporal patterns are vital to the sustainability of ecosystem management. However, the spatialization of the correlation between the relationships among ESs and the influencing factors has remained a difficult analysis for the Qinghai-Tibet Plateau (QTP). Consequently, three ESs are quantified using different models, and synergies and trade-offs among the ESs are analyzed. The precipitation changes, minimum temperature changes, gross domestic product changes, population changes, normalized difference vegetation index (NDVI) changes, and the digital model (DEM) were selected as influencing factors. The influence of these influencing factors on the relationship among the ESs was then measured using the methods of logistic regression (LR) and the geographically weighted logistic regression (GWLR). The authors showed that (1) the spatially concordant high supplies of water yield (WY) and carbon storage (CS) were distributed in the southeastern forest areas and the eastern grassland areas, whereas high meat supply (MS) was primarily distributed in the eastern and the middle of the grassland areas. (2) The relationships between the WY and MS and between the CS and MS were primarily trade-offs, and their area ratios were 40% and 41%, respectively. However, the relationship between the WY and CS was primarily synergistic, and the area ratio was 54%. (3) Precipitation was more highly related to the relationships among the ESs than the other influencing factors among the six independent variables. Compared to the LR, the GWLR model provides an improved calculation to explain the correlation between the relationships among the ESs and these influencing factors. Overall, it was found that these influencing factors on the impacts of the relationship among the ESs were different, and they lacked spatial concordance. These results highlight the importance of managing nearly all areas by specifically controlling local factors.

Phylogeography and morphometric variation of the Spike-heeled Lark Chersomanes albofasciata complex

The Spike-heeled Lark Chersomanes albofasciata is a peculiar, short-tailed lark confined to southern, central and East Africa. Typical of resident larks, it exhibits marked geographic variation in plumage colour, which has historically resulted in large numbers of subspecies being described. This variation was examined by sequencing 630 base pairs of the cytochrome b gene in 39 individuals and morphometric measurements of 320 birds. Nine of the 14 southern African C. albofasciata subspecies defined by Clancey in 1980 were sampled for assessing genetic variation, as well as one population from northern Namibia (C. a. boweni) and the isolated C. [a.] beesleyi population in Tanzania. Within South Africa, 16 maternal lineages were identified. The haplotype network revealed three geographically distinct haplogroups: Namaqualand, Karoo and Eastern grasslands, which did not follow past or existing subspecies ranges. Our data thus suggest incongruence between genetic variation and phenotype in South Africa. The boundaries and relationship among the phylogeographic haplogroups and morphometric measurement were similar to the closely related Long-billed Lark Certhilauda curvirostris complex suggesting similar processes during their evolutionary history. The existing subspecies designations are clearly not supported by the genetic data presented here and thus more research into this complex is required. Further research should include sampling of Spike-heeled Larks in underrepresented areas of the species’ range and the use of additional genetic markers to improve our understanding of the evolutionary history of this complex. C. [a.] beesleyi was sister to all haplotypes sampled and smaller in size than all subspecies measured. Although the status of the contentious C. [a.] beesleyi has still not been resolved, we have added morphometric data supporting its isolation from other subspecies. Its limited and isolated range warrants increased conservation efforts and we propose its recognition as an evolutionarily significant unit.

Study on shaping slope stability of dump in eastern grassland open-pit mine

The dumps in the open-pit mining area in the eastern grassland are prone to landslides due to the fragile ecological environment, so it is inevitable to reshape the dump slopes. In order to explore a more scientific method for slope shaping of open-pit mine dump, slope stability analysis were used to compare effect of three types of slope-type (wave-shaped, slope-shaped and step-shaped slope shaping method)in outside dumping site of Baori Hiller open-pit mine. The results show that the slope stability is negatively correlated with the slope angle, and the stability of different shaping slopes is realized as wave-shaped slope (F=2.711)> Slope-shaped slope(F=2.513)>Step-shaped slope(F=1.047), in which the wave type and slope type are all within the safe range, but the step type slope is unstable; in consideration of cost, stability and erosion resistance, it is better to set the slope angle of the dump to 15°.The wave-shaped shaping method of the natural dumping of the excavation field outside the Baori Hiller open-pit mine has the best effect and is worth promoting.

Eastern grasslands: Conservation challenges and opportunities on private lands

ABSTRACTGrasslands were once common in the eastern United States and provided habitat for numerous grassland‐dependent wildlife. However, native grasslands in this region have largely been eliminated as a result of conversion to other land uses (e.g., urban development, row‐crops), altered disturbance regimes (e.g., lack of fire and grazing), or conversion to introduced grasses for livestock production. Consequently, many wildlife species adapted to these environments have experienced protracted population declines, notably, northern bobwhite (Colinus virginianus), and other grassland‐dependent bird species. Restoration of native grasslands with appropriate native plant species composition, structure, and disturbance regimes will be key to restoring at‐risk wildlife. Indeed, the region still includes >20 million ha of grasslands, but these are dominated by introduced grass species and focused on cattle (Bos taurus) production. Any successful restoration strategy must engage the agricultural community, provide profitable forage production, and benefit habitat for wildlife. Furthermore, grassland ecosystems in humid regions (i.e., >95 cm annual rainfall) require frequent disturbance to prevent succession to forested conditions. Historically, these native grasslands were maintained by fire, herbivory, and their interaction. Consequently, wildlife communities in humid, native grasslands are adapted to those same disturbances and the conditions they create. Improving species composition by replacing introduced, sod‐forming grass species commonly used in production agriculture (e.g., tall fescue [Schedonorus arundinaceus] and bermudagrass [Cynodon dactylon]) with native grasses can be beneficial but must be accompanied by appropriate disturbance to achieve and maintain improved habitat. Therefore, developing a business case for producers to incorporate native grasses into regional agro‐grasslands that include disturbance through grazing may foster large‐scale improvements in habitat quality. Although Farm Bill conservation practices can make important contributions to conservation of eastern grassland‐dependent wildlife, such programs are dependent on uncertain and limited federal budgets and, to provide appropriate disturbance, require management intervention at a net cost to landowners and Farm Bill programs. Thus, there exists an opportunity to improve habitat at a scale that has the potential to sustain viable populations of grassland‐dependent wildlife. Therefore, we discuss the potential of a new conservation paradigm, one based on grazing systems that utilize native grasses, for filling that conservation gap. © 2019 The Wildlife Society.

Effects of grassland management on overwintering bird communities

ABSTRACTBirds that depend on grassland and successional‐scrub vegetation communities are experiencing a greater decline than any other avian assemblage in North America. Habitat loss and degradation on breeding and wintering grounds are among the leading causes of these declines. We used public and private lands in northern Virginia, USA, to explore benefits of grassland management and associated field structure on supporting overwintering bird species from 2013 to 2016. Specifically, we used non‐metric multidimensional scaling and multispecies occupancy models to compare species richness and habitat associations of grassland‐obligate and successional‐scrub species during winter in fields comprised of native warm‐season grasses (WSG) or non‐native cool‐season grasses (CSG) that were managed at different times of the year. Results demonstrated positive correlations of grassland‐obligate species with decreased vegetation structure and a higher percentage of grass cover, whereas successional‐scrub species positively correlated with increased vegetation structure and height and increased percentages of woody stems, forb cover, and bare ground. Fields of WSG supported higher estimated total and target species richness compared to fields of CSG. Estimated species richness was also influenced by management timing, with fields managed during the previous winter or left unmanaged exhibiting higher estimated richness than fields managed in summer or fall. Warm‐season grass fields managed in the previous winter or left unmanaged had higher estimated species richness than any other treatment group. This study identifies important winter habitat associations (e.g., vegetation height and field openness) with species abundance and richness and can be used to make inferences about optimal management practices for overwintering avian species in eastern grasslands of North America. © 2019 The Authors. Journal of Wildlife Management Published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Disturbance reduces the differentiation of mycorrhizal fungal communities in grasslands along a precipitation gradient.

Given that mycorrhizal fungi play key roles in shaping plant communities, greater attention should be focused on factors that determine the composition of mycorrhizal fungal communities and their sensitivity to anthropogenic disturbance. We investigate changes in arbuscular mycorrhizal (AM) fungal community composition across a precipitation gradient in North American grasslands as well as changes occurring with varying degrees of site disturbance that have resulted in invasive plant establishment. We find strong differentiation of AM fungal communities in undisturbed remnant grasslands across the precipitation gradient, whereas communities in disturbed grasslands were more homogeneous. These changes in community differentiation with disturbance are consistent with more stringent environmental filtering of AM fungal communities in undisturbed sites that may also be promoted by more rigid functional constraints imposed on AM fungi by the native plant communities in these areas. The AM fungal communities in eastern grasslands were particularly sensitive to anthropogenic disturbance, with disturbed sites having low numbers of AM fungal operational taxonomic units (OTUs) commonly found in undisturbed sites, and also the proliferation of AM fungal OTUs in disturbed sites. This proliferation of AM fungi in eastern disturbed sites coincided with increased soil phosphorus availability and is consistent with evidence suggesting the fungi represented by these OTUs would provide reduced benefits to native plants. The differentiation of AM fungal communities along the precipitation gradient in undisturbed grasslands but not in disturbed sites is consistent with AM fungi aiding plant adaptation to climate, and suggests they may be especially important targets for conservation and restoration in order to help maintain or re-establish diverse grassland plant communities.

The sensitivity of carbon exchanges in Great Plains grasslands to precipitation variability

AbstractIn the Great Plains, grassland carbon dynamics differ across broad gradients of precipitation and temperature, yet finer‐scale variation in these variables may also affect grassland processes. Despite the importance of grasslands, there is little information on how fine‐scale relationships compare between them regionally. We compared grassland C exchanges, energy partitioning and precipitation variability in eight sites in the eastern and western Great Plains using eddy covariance and meteorological data. During our study, both eastern and western grasslands varied between an average net carbon sink and a net source. Eastern grasslands had a moderate vapor pressure deficit (VPD = 0.95 kPa) and high growing season gross primary productivity (GPP = 1010 ± 218 g C m−2 yr−1). Western grasslands had a growing season with higher VPD (1.43 kPa) and lower GPP (360 ± 127 g C m−2 yr−1). Western grasslands were sensitive to precipitation at daily timescales, whereas eastern grasslands were sensitive at monthly and seasonal timescales. Our results support the expectation that C exchanges in these grasslands differ as a result of varying precipitation regimes. Because eastern grasslands are less influenced by short‐term variability in rainfall than western grasslands, the effects of precipitation change are likely to be more predictable in eastern grasslands because the timescales of variability that must be resolved are relatively longer. We postulate increasing regional heterogeneity in grassland C exchanges in the Great Plains in coming decades.

Comparing susceptibility of eastern and western US grasslands to competition and allelopathy from spotted knapweed [Centaurea stoebe L. subsp. micranthos (Gugler) Hayek

Centaurea stoebe L. subsp. micranthos is native to Eurasia and is invasive in the western portion of the US. Negative impacts of C. stoebe micranthos present in the eastern US have not been recorded. In this study, we examine the effects of C. stoebe micranthos on species diversity on an eastern grassy bald, compare the competitive abilities of plant species from eastern and western grasslands against C. stoebe micranthos, and assess the production of allelopathic compounds in an eastern population of C. stoebe micranthos. Field observations indicated that increasing C. stoebe micranthos abundance was not associated with decreasing abundance or diversity of species. In a greenhouse experiment, C. stoebe micranthos growing with plant species from an eastern grassland were smaller than C. stoebe micranthos growing with species from western grasslands, suggesting that species from the eastern grassland are more competitive against C. stoebe micranthos. We found no evidence that the eastern population of C. stoebe micranthos has allelopathic effects. While the invasion dynamics may change over time, the possibility that C. stoebe micranthos may never become invasive in the studied grassy bald should be weighed when considering control measures here and throughout the eastern US. This study illustrates that invasion dynamics can vary geographically and that land managers need relevant information to gauge an appropriate and economical response.

Conservation priorities for the Blue Crane (Anthropoides paradiseus) in South Africa — the effects of habitat changes on distribution and numbers

Detailed knowledge on population numbers, habitat preferences and threats is lacking for the Blue Crane (Anthropoides paradiseus), which is endemic to southern Africa and is South Africa's national bird. Using the South African Bird Atlas Project Blue Crane distribution as the accepted distribution of the species, this analysis has shown three distinct core areas for the population determined by a core index value. The largest of these core areas occurs in the central Karoo region covering 153 153km2. The next largest core area was in the Eastern Grassland region covering 137 838km2. The final core area is located in the areas known as the Overberg and Swartland of the Western Cape province, encompassing 23 440km2. The annual National Crane Census in South Africa, which covered 40% of the Blue Crane's distribution, has resulted in the determination of the actual minimum population size of 25 520 individuals. An assessment of the Blue Crane's distribution in relation to the vegetation composition of the three core areas shows that it has experienced a dramatic decline in population numbers in the Eastern Grasslands core area, where a significant degree of grassland transformation and fragmentation has occurred. The Central Karoo population has remained stable and comprises 42.4% of the current national population estimate. More than 42% of this core area comprises Nama Karoo vegetation with little habitat transformation. The most significant change has occurred in the Western Cape, which historically consisted of unsuitable Blue Crane habitat. The conversion of Fynbos and Renosterveld to 'artificial grasslands' through agricultural developments has created a favourable habitat for Blue Cranes, with this core area, comprising only 7.6% of the total core area in the country, having 47.4% of the national population. The conservation of the Blue Crane in these core areas relies on private landowners implementing management plans that allow the Blue Crane to coexist in an agricultural landscape. Knowledge through applied research will allow the identification of preferred habitats, breeding locations and suitable management activities. The landscape approach of conservation allows the benefits of ecosystem management to be realised for both people and the biodiversity elements.

Revision of the ant genus Streblognathus (Hymenoptera: Formicidae: Ponerinae)

The southern African ant genus Streblognathus has long been regarded as being monotypic but a morphological reappraisal of available specimens shows that there are two species: Streblognathus aethiopicus (F. Smith), which occurs in the southern karoo of the Eastern Cape, and Streblognathus peetersi sp. nov., which occurs in the eastern grasslands of southern Africa. Workers and males are described and keyed. Male genitalia are illustrated and the significance of the large barbs on the penis valves is discussed.

Frequency and Extent of Water Limitation to Primary Production in a Mesic Temperate Grassland

The frequency and extent of water limitation to aboveground net primary production (ANPP) in a mesic grassland in NE Kansas (Konza Prairie, USA) was assessed with an 8-year irrigation experiment. Since 1991, transects spanning upland and lowland sites in annually burned, ungrazed tallgrass prairie were provided with supplemental water to satisfy evapotranspirational demands. This protocol minimized water limitations during the growing season, as well as interannual variability in water stress. Irrigation of this mesic grassland increased ANPP in 6 of 8 years by an average of 26% when compared to control transects. Although interannual variation in ANPP was greater in uplands than lowlands at nominal levels of precipitation, reducing interannual variability in water availability via irrigation eliminated topographic differences; the irrigation protocol also reduced interannual variability in ANPP by as much as 40%. The addition of supplemental water enabled us to extend the relationship between annual precipitation and ANPP in grasslands to precipitation levels (average, 1153 mm; maximum, 1346 mm) similar to those experienced by more mesic grasslands that today exist only as remnants several hundred kilometers east of Kansas. This relationship was linear (r 2= 0.81), with maximum ANPP (738 g/m2) similar to values reported for sites in Illinois and Wisconsin. After 8 years of irrigation, production of the C3 forb component was twice that in control sites. These results indicate that water limitations in grasslands at the western edge of the presettlement extent of tallgrass prairie affect ANPP in most years and that this high frequency of water limitation may lead to greater dominance of the C4 grasses than is seen in more eastern grassland sites.

Karyotypic variation in populations of deer mice (Peromyscus maniculatus) from eastern Canada and the northeastern United States

The karyotypes of deer mice (Peromyscus maniculatus) from populations of five subspecies from the northeastern United States and eastern Canada were analyzed by G- and C-banding. Within an invariant diploid number of 48, intra- and inter-populational variation in the number of autosomal arms (80-86) was attributable to a pericentric inversion (chromosome 8) and (or) the presence of heterochromatic short arms (chromosomes 8, 10, 12, and 19). The plesiomorphic (noninverted) condition of chromosome 10 in these five populations is unique among deer mice; previous chromosome-banding studies of P. maniculatus report data for geographically central or western populations and indicate only the derived (inverted) condition of chromosome 10. As the plesiomorphic condition of chromosome 10 is apparently restricted to the northeastern forest form of P. maniculatus, the morphology of this chromosome potentially represents a simple and discrete character for resolving the historically problematic question of the specific status of the eastern grassland and forest morphotypes of deer mice.

Small mammal communities in North American grasslands.

Small mammal communities in North American grasslands usually contain 10 to 15 species, including carnivores, insectivores, lagomorphs and rodents. The most diverse group, the rodents, has species that primarily eat insects, monocotyledons, dicotyledons or seeds, as well as species that are omnivorous. Western grasslands have summer drought and many species found there, particularly heteromyid rodents, are also found in western deserts. The wetter eastern grasslands contain insectivores and rodents that also occur in eastern forest meadows The occurrence and relative abundance of particular species at any site depends upon at least three factors: vegetational characteristics (cover and food availability), abundance of predators and abundance of competing species. A literature review indicates that competitive effects have been particularly well documented among grassland rodents. These effects range from subtle habitat shifts to competitive exclusion and appear to be directly related to the amount of overlap in diet and to the density of the dominant competing species.