Rangeland Ecology & Management最新文献

Landscape distribution and grazing management of small ruminants are becoming more important issues as the sheep and goat industry continues to grow. The objective of this study was to evaluate spatial movement patterns of sheep and goats in Queensland, Australia using Global Positioning System (GPS) tracking to determine daily distance traveled, distance traveled from water, activity levels, and the influence of ambient temperature on these metrics. Optimized hotspot analysis was also performed to determine areas of increased small ruminant presence across the landscape. GPS positions were recorded at 10-min intervals over the course of several months. Sheep and goats traveled an average distance from water of 0.6–1.1 km, with a maximum of 2.4 km. Daily distance traveled of sheep and goats averaged 6–9 km·d⁻¹, with a maximum of 11 km·d⁻¹. Average daily activity ranged between 42% and 47%. The overall trend of the datum showed that increased temperature led to decreased daily distance traveled, distance traveled from water, and activity of sheep and goats. The hotspot analyses showed a higher concentration of sheep and goats near water sources. Understanding small ruminant distribution in extensive rangeland pastures helps producers implement management regimes to improve efficacy and sustainability of land use and production.

Yak herding, a market-based tradition, is vanishing gradually. The changing environment such as climate change, policy context, and socioeconomic change is not in favor of yak herding. Using a choice experiment survey approach, this study determines the yak herders’ preferences to improve yak herding in Kanchenjunga Landscape, Nepal. The results of the choice response analysis indicate that yak herders prefer to improve yak herding by improving rangeland management, infrastructure, and health and safety services. Herders have a high preference for yak insurance (US dollar [USD] 6.82/yak), followed by cultivating an improved variety of grass in rangeland (USD 6.71/yak), improved health services (USD 5.68/yak), allowing controlled burning (USD 4.72/yak), and permanent structure of shed (USD 4.39/yak). Additionally, this analysis suggests that a policy is required to allow controlled burning to improve the condition of rangeland, which can contribute to reducing the encroachment of shrubs. Similarly, there is also a need to further explore the appropriate insurance mechanism for yaks to involve all yak herders and reduce their risk.

Soil moisture characteristic curves (SMCCs) play a crucial role in understanding and managing soil-water relationships, which is vital in various fields including agriculture, civil engineering, environmental science, and hydrology. This study investigates the impact of livestock grazing, slope location, and sampling depth on SMCCs in the Gonbad watershed, western Iran. Livestock grazing practices were compared between free grazing and controlled grazing, along with three slope positions (shoulder, back, and foot-slope) and two sampling depths (0−12.5 cm and 12.5−25 cm). The van Genuchten model was employed to model the SMCC, incorporating Mualem's assumption. Water content at different matric suctions and van Genuchten model parameters were assessed using a factorial design. Integral root mean square difference (IRMSD) and surface difference (SD) parameters were calculated to evaluate the impact of different treatments on the SMCC, as a whole. The controlled grazing treatment at the back-slope recorded the lowest residual water content, measuring 0.151 cm³ cm⁻³ in the 0.00- to 12.5-cm depth. Conversely, the highest value of 0.234 cm³ cm⁻³ was observed in the free grazing treatment at the shoulder, specifically in the 12.5- to 25-cm depth. The results indicate that the permanent wilting point (PWP) value at the second depth exceeded that of the first depth. Specifically, at the second depth, the PWP value in the shoulder region of the slope under free grazing (0.235 cm³ cm⁻³) surpassed that of the corresponding position under controlled grazing (0.192 cm³ cm⁻³). The findings revealed that the highest α parameter value (0.438 cm⁻¹) was observed at the first depth of the back-slope position under the controlled grazing treatment. Results indicated significant effects of grazing, slope position, and sampling depth on soil properties and SMCC parameters. Notably, controlled grazing led to higher values of IRMSD (0.178 cm³ cm⁻³) and SD (0.672 cm³ cm⁻³), indicating enhanced moisture retention capabilities compared with free grazing. The study provides valuable insights into optimizing grazing practices for sustainable soil health and water management in pasture ecosystems.

Ecological site descriptions have become a prominent way of describing plant communities across rangelands. Disturbance response groups (DRGs) stratify landscapes by grouping ecological sites on the basis of their responses to natural or anthropogenic disturbances. DRGs allow managers to organize, scale, and evaluate information collected on the ground, thus creating expectations of how sites with similar characteristics will respond to disturbance and management. While the importance and utility of these concepts are well understood, the location and spatial extent of DRGs are not. Uncertainty of DRG location and extent make it challenging to evaluate trends or degradation risks of a given area and difficult to define and organize adaptive management concerns and opportunities on a landscape scale. DRGs are organized by major land resource areas (MLRAs), which can make real-life applications across MLRA boundaries for natural phenomena (e.g., wildfire boundaries) repetitive for specific management objectives. Vegetative great groups have been used to overcome this challenge while retaining the state-and-transition model importance of ecological sites. Presented here is a gridded process for vegetative great group mapping across MLRA boundaries, as well as an assessment of the ecological implications of the information gained about the plant communities through the mapping efforts. The scale and output are designed to fit the Landsat library grid and its derived information. Computer machine learning was used to generate spatial maps of vegetative great groups that were compared with Natural Resources Conservation Services soil survey maps, which are currently used by public land management agencies. Machine learning enhanced accuracy by 14% versus conventional soil mapping, providing a more accurate way to conceptualize and manage plant communities at the landscape scale. Further, predictor variables used in machine learning can supplement our knowledge of ecological process information on sites and aid land managers in understanding the various plant community responses to disturbance.

In temperate landscapes, habitat selection is constrained by resource availability during winter. Most studies of habitat selection by greater sage-grouse (Centrocercus urophasianus “sage-grouse”) have focused on breeding and summer rather than winter habitat. We focused on winter microhabitat when available habitat was influenced by snow conditions. Our objectives were to 1) identify what microhabitat characteristics sage-grouse select during winter and 2) evaluate whether sage-grouse selected microhabitat at the home range (third order) or the population range (second order) scale. In summer 2020, we measured shrub characteristics and herbivore dung counts at 90 sage-grouse locations from the previous 2019/2020 winter in northwest Colorado and southcentral Wyoming and compared them with 90 paired, available locations within sage-grouse home ranges and 90 unpaired, available locations within the population range. We found strong support for sage-grouse selecting for winter microhabitat at the home-range scale because we observed similar differences in shrub characteristics between sage-grouse use locations and available locations at both scales and no differences between randomly available habitat. Compared with available locations within home ranges, wintering sage-grouse selected areas of 57.1% greater big sagebrush (Artemisia tridentata spp. Nutt.) canopy cover, 23.7% taller big sagebrush, and 110.6% more visual obstruction at use locations. Sage-grouse dung piles were 7.1 × higher at used locations than available locations within home ranges, further indicating that habitat use was less random within home ranges. In winter, microhabitat selection focused on higher cover and height of big sagebrush like previous observations from nearby studies of microhabitat selected by sage-grouse during nesting and brood-rearing.

Invasive annual grasses have degraded tens of millions of hectares of the sagebrush ecosystem of western North America. Restoration of perennial vegetation in annual grass−invaded rangelands is a management priority to decrease fire risk, increase livestock forage quality, and improve wildlife habitat. Annual grasses are traditionally controlled in the fall with preemergent herbicides, such as imazapic, and treated areas are often seeded with perennial bunchgrasses 1 yr later to avoid nontarget herbicide damage to revegetation species. However, there is a limited window of time in the fall to accomplish annual grass control treatments. Spring-applied control treatments may be another option compared with only fall control treatments, but they have received little attention. We imposed spring-applied annual grass control treatments followed by fall seeding of a perennial bunchgrasses and then measured vegetation response for the next 3 yr in cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae)−invaded communities. Spring treatments that included imazapic application (at a low rate), followed by fall seeding of perennial bunchgrasses, successfully controlled annual grasses and substantially increased perennial bunchgrass cover and density. Spring burning and glyphosate herbicide application, without imazapic, were not successful in promoting substantial increases in perennial bunchgrass cover. Spring burning before imazapic application was the most successful treatment for rehabilitation seeding. By the third yr after seeding, perennial bunchgrass cover was 17% in the spring burn−imazapic treatment, greater than what is generally found in intact Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis)-bunchgrass communities in this region. The results of this study provide strong evidence that spring-applied control treatments including imazapic can be part of successful revegetation efforts, thereby decreasing some of the logistical challenges associated with revegetation of annual grass−invaded sagebrush rangelands.

Aerial spraying of herbicides is an option for treating undesirable woody species on grasslands and rangelands, but few studies have determined effects of these products on nontarget woody plants important to wildlife. A recently introduced herbicide containing a mixture of clopyralid and aminopyralid (CA) is thought to be specific to honey mesquite (Prosopis glandulosa) control. Our objective was to document effects of CA alone and mixed with other brush herbicides, including picloram and triclopyr, on two target species, honey mesquite and pricklypear (Opuntia spp.), and two nontarget woody plants, lotebush (Zizyphus obtusifolia) and hackberry (Celtis laevigata var reticulata). Treatments were 1) CA, 2) CA + triclopyr (CA + Tr), 3) CA + picloram (CA + Pc), and 4) clopyralid + triclopyr (Cp + Tr). We applied aerial spray treatments on four, 4-ha replicated plots of mature mesquite thickets that also contained pricklypear in each of 3 consecutive yr in north-central Texas and evaluated plots at 1 yr and 2 yr post treatment (YPT). We developed a tolerance-rating model with five levels (highly tolerant, tolerant, moderately tolerant, moderately susceptible, and susceptible) that integrated stand-level percent whole plant mortality (root-kill) and percent canopy reduction of surviving plants. Mesquite was susceptible to all treatments in all spray years. Pricklypear was susceptible to CA + Pc (root-kill more than doubled [33−84%] from 1 to 2 YPT) but highly tolerant of the other treatments. Lotebush was highly tolerant or tolerant of all treatments. Hackberry was tolerant of CA and Cp + Tr but susceptible to CA + Pc. The negative effect of CA + Pc on hackberry was greater when hackberry was drought stressed. We recommend inspection of drought status, foliage condition, and abundance of nontarget woody species before broadcast spraying for control of targeted woody species or cacti.

Land-use intensification threatens biodiversity conservation of grasslands worldwide. One example of intensification is overseeding legumes in natural grasslands coupled with phosphorus fertilization, a management practice oriented to increase forage production and quality. Several studies show increases in forage due to this practice, at least in the short term, but less is known about impacts on diversity. We analyzed the effects of overseeding Lotus suaveolens cv. “El Rincón” coupled with phosphorus fertilization on plant diversity and composition of natural grasslands of Uruguay. We used floristic data from 29 intensified versus natural paired paddocks from a geographical wide net of observations distributed across two separated areas with distinct plant communities. Besides, a set of land-use intensification indicators were used to explore its relationship with intensification impact on plant composition and diversity. Overall, the effects of overseeding with legumes and fertilization on species richness (total, native and exotic richness) and beta diversity depended on community type. Our data evidenced that the Eryngium horridum−Juncus capillaceus community lost native species with intensification, affecting total richness that showed a 15.3% decrease. The Steinchisma hians−Piptochaetium stipoides community, in turn, was enriched by exotic species. It increased 96.4% but without affecting total species richness. Beta diversity, for its part, showed a reduction associated with intensification only in the S. hians-P. stipoides community. Our results show that neither amount of applied fertilizer nor time since overseeding and fertilizing were directly related to intensification impacts. These findings highlight the importance of accounting for various dimensions of diversity to assess community responses to land use changes. Our results point out that even slight intensification affects plant diversity of Campos Grasslands. The lack of predictability of impact magnitude by simple land-use intensity indicators challenges prevention and mitigation of this technology.

The invasion of exotic annual grasses including cheatgrass (Bromus tectorum), medusahead (Taeniatherum caput-medusae), and North Africa grass (Ventenata dubia) have drastically altered grassland ecosystems across the western United States. Continuous efforts have been made to reclaim these ecosystems through the application of annual grass selective herbicides. The effectiveness of these herbicides and the response of vegetation post application is well documented, but research is lacking in how these treatments directly affect mule deer (Odocoileus hemionus) forage quality, quantity, and composition throughout the year. Our objectives were to evaluate the efficacy of using imazapic (Open Range G, Wilbur-Ellis) to improve summer mule deer forage and assess the potential negative effects of the herbicide on winter forage availability. In fall of 2020, imazapic was applied to fifteen, 8-ha plots established within telemetered mule deer home ranges located in grassland habitat surrounding Heppner, Oregon, United States. Paired treatment and control plots were monitored for 2 yr in the summer and fall of 2021 and summer of 2022. Our results suggest that imazapic applications can be used to increase the nutritional quality of forage but may temporarily reduce the quantity of forage available in the first summer after treatment. In the second summer, forage biomass increased significantly but crude protein and digestible energy contents of forage were no longer superior within treatment plots. Imazapic applications had no effect on winter forage biomass or nutritional quality of forage available. Imazapic treatments appear to be an effective strategy to improve summer mule deer forage quality and quantity without adversely affecting winter food sources.

We investigated factors influencing codistribution of cattle and exotic oryx on the Chihuahuan Desert Rangeland Research Center (CDRRC), south-central New Mexico. We established a camera-trapping grid on the CDRRC, 2019–2022, and modeled occupancy of cattle (Bos indicus) and oryx (Oryx gazella gazella) as a function of habitat attributes and presence of the other species. Species interaction factors were > 3.9 for oryx and cattle, and presence of either ungulate never negatively influenced occupancy of either except at water sites. Similarly, occupancy of the CDRRC landscape was positively correlated (≥ 0.77) between oryx and cattle. Occupancy of oryx was weakly negatively influenced by total edge and terrain ruggedness. Cattle occupancy was weakly associated with areas away from roads, nearer water, and with greater number of habitat patches in the landscape (i.e., within a 1-km radius). Presence of oryx and cattle at water sites was negatively correlated (r = –0.20); patterns of use indicated that oryx avoided using water sites when cattle were present. Rather than segregation driven by interference competition or despotism, our results appeared to reflect common preferences and distribution of oryx and cattle for much of the CDRRC landscape. The exception to this was apparent subdominance of oryx to cattle at water sites.