Rangeland Ecology & Management最新文献

Huisache (Vachellia farnesiana (L.) Wight & Arn.) is a pest tree species on rangelands throughout South Texas and is expanding in range and density, due in part to prolific seed production. We aimed to determine the optimum diurnally-fluctuating temperature conditions for huisache seed germination by testing scarified and nonscarified seed in four temperature treatments: 35/25, 30/20, 25/15, and 20/10°C. We used alternating 12-hour light/dark photoperiods in a growth chamber, and seed germination was recorded daily. Germination of scarified and nonscarified seeds at each temperature treatment was analyzed via ANOVA for a completely randomized design (with appropriate posthoc tests). Although total cumulative germination percentages were similar among temperature treatments, seeds in the 20/10°C temperature treatment germinated more slowly. In addition, scarified seeds germinated more quickly, and with greater total percent germination. Results show that huisache seeds can be expected to germinate over a wide range of temperatures, with germination slowing when temperatures are low. Because we found huisache seeds germinated slowly in cooler temperatures, landscape managers may consider prioritizing control efforts of recently-germinated seedlings following warmer, wetter weather.

Virtual fencing (VF) is a rapidly expanding technology that uses global positioning technologies to send audible and electrical cues to livestock that create invisible boundaries to replace physical fencing. The technology portends several benefits, from replacing costly and hazardous physical fencing to being an additional tool to contain, exclude, or move livestock. While researchers and VF providers work to improve the technology and applications, little is known about producer perceptions of its capabilities and what they most want in a system. We conducted phone and in-person interviews with beef cattle producers to ask them about their views and experiences related to virtual fencing technology. We included producers that already use the technology (including producers currently installing the technology) and producers not actively considering or using the technology. Our findings identify benefits and barriers of VF from the cattle producers’ perspective. These perspectives can guide new research, improve VF technology, guide educational programs, and help producers considering a VF system. Survey responses are organized into eight themes: animal stress and welfare; effectiveness, function, and technology; management impacts; financial and economic perspectives; improvements and advice; learning; privacy; and implementation. Producers who use the technology had greater optimism about the applications and economics and have found creative applications of VF specific to their operations. While they have more confidence in the technology, they still report issues such as collars falling off or base stations not working. Producers new to VF should expect a learning period both for themselves and their animals. Producers from all groups cite potential benefits from better use of forages, reduced wildlife conflicts, more flexibility and convenience, to the ability to better manage sensitive landscapes such as riparian areas or other areas affected by fire or drought.

This study presents a comprehensive analysis of Alpine pastures in the Kashmir Himalayas through a multidisciplinary approach, combining remote sensing and field-based assessments for biomass estimation and time series analysis of the (NDVI) Index for the growing season from May to October 2022. The Alpine and Subalpine region of Kashmir was delineated using ALOS PALSAR Digital Elevation Model, and Landsat 8 imagery was classified using a maximum likelihood algorithm, revealing a total grassland area of 160,974 hectares. After grassland delineation Biomass estimation was carried out based on data collected from 18 pastures, each of which was subjected to a stratified sampling approach to establish four 1 m² quadrats, with two designated for grazed areas and two for ungrazed areas, this yielded average biomass yields of 20.87 t/ha and an average dry weight biomass of 5.16 t/ha. Pastures like Daksum (28.36 t/ha), Tragbal (28.22 t/ha), Krush (27.83 t/ha), Lung Marg (27.03 t/ha), observed high biomass availability, while moderate levels were found in locations like Gangbal (22.75 t/ha), Hangel Marg (22.68 t/ha), Dagwan (21.76 t/ha), Gumri (20.82 t/ha), Bangus (20.66 t/ha), Pir Galli (18.52t/ha), Maalish (18.21 t/ha), In contrast, lower biomass values were recorded in Mohand Marg (11.47 t/ha), and Thajwas (9.81 t/ha). These findings were complemented by (NDVI) metrics, which varied across sites. For example, high NDVI values were observed for sites such as Pir Gilli, Bangus, and Kud Marg, indicating a healthier vegetative profile with less impact of grazing during the grazing season. In contrast, pastures like Mohand Marg, Thajwas, Razdan, and Tragbal recorded moderate NDVI values, suggesting a moderate level of grazing impact. Pasture sites with lower NDVI values and high standard deviation, such as Hangel Marg and Gumari, witnessed high seasonal variability, suggesting a high grazing impact, besides other natural factors responsible, like early snowfall. The study emphasizes the need for ongoing, multifaceted ecological assessments for the sustainable management and conservation of these critical Alpine ecosystems.

Residents of the Sahel depend on livestock, but harsh environmental conditions during the dry season limit rangeland forage, which is the main source of livestock feed. Al-though operational tools exist for assessing and monitoring forage quantity during the dry season, assessments of forage quality are lacking. We addressed this gap by developing satellite-based monitoring of forage quality across Sahelian rangelands during the dry season. Acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein (CP) content (%) were measured in forage samples collected from 11 sites across the Senegalese rangelands in 2021. Multilinear (MML) regression and support vector machine (SVM) models were calibrated with spectral indices to estimate these parameters of forage quality. The vegetation variables assessed were herbaceous mass (HQ), woody foliage mass (LQ), and total fo-rage mass (HLQ). The MML regression provided the most accurate estimates for CP (HQ: R² = 0.81, LQ: R² = 0.72, and HLQ: R² = 0.70), ADF (HQ: R² = 0.70, LQ: R² = 0.77, and HLQ: R² = 0.61), and NDF (HQ: R² = 0.47, LQ: R² = 0.83, and HLQ: R² = 0.60). Temporal analysis revealed a slight decrease in CP and an increase in fiber during the dry season. Spatial analysis indicated that CP was higher in the steppe zone than in the savanna zone, and a decrease correlated with the rainfall gradient. The HQ alone was insufficient to meet livestock needs during the dry season, highlighting the importance of woody plants as an additional forage source. These findings will improve feed balance calculations in Sahelian countries, enable more sustainable use of rangelands, and contribute to the resilience of Sahelian communities to climate change.

A comprehensive understanding of how native grasslands (rangelands) respond to chronic nutrient addition requires considering interactions with climate variability, water availability in particular, and with stocking rate management. We assessed animal production responses to phosphorus plus nitrogen fertilization sustained over a decade on a highly diverse subtropical grassland. Between 2002 and 2011, paddocks (2 ha) stocked with Hereford heifers received 15 kg P + 50 kg N/ha in April/May, plus 50 kg N/ha in August/September, or were left as unfertilized controls (n = 2). Monthly, independent per-paddock, put-and-take adjustment of stocking rates kept sward height within the 6–12 cm range across all paddocks and years. Herbage production, stocking rate, and liveweight gain per animal (LWG_A) and per hectare (LWG_H) were measured over the 10 consecutive one-year cycles. Fertilization increased LWG_H (+53%) because it increased both herbage production (+32%) and liveweight production per unit produced herbage (trophic efficiency +29%). Such higher trophic efficiency was not a direct effect but a consequence of the increased grazing intensity brought about by the 48% higher stocking rate required to maintain target sward heights in fertilized paddocks, especially in winter and spring. Fertilization increased LWG_H substantially more in years with higher summer precipitation. Considering that nutrients were added in autumn–winter, greater responses in wetter summers suggest active excreta-driven nutrient recycling between the sequential growth of cool- and warm-season species. Nutrient addition did not decrease temporal stability of herbage production, LWG_A or LWG_H. A stocking rate management that precluded fertilized paddocks from becoming taller than unfertilized controls, hence mitigating competition for light, could be the reason underlying this unexpected result. By disentangling intrinsic effects of fertilizers from grazing regime-mediated effects, this study helps understand how extensive animal production (agroeco) systems reliant on highly diverse rangelands respond to progressive nutrient enrichment.

In response to the challenge of simultaneously controlling invasive plant species and restoring desired species, seed technologies have been developed that use activated carbon to protect desired plants from pre-emergent herbicides that target invasive plants, such as herbicide protection pellets (HPPs). One ecosystem imperiled by this challenge is the sagebrush steppe of the Western United States. Land managers in the sagebrush steppe may use consecutive or concurrent applications of different pre-emergent herbicides in order to control invasive annual grasses while restoring desirable perennial vegetation that helps stabilize soil and reduce the frequency of wildfires. We conducted a pot study looking at the efficacy of HPPs for six perennial species with novel herbicide practices used by land managers: an application of both imazapic and indaziflam. The six test species included four bunchgrasses, one shrub, and one forb. The bunchgrass species responded well to the HPPs with similar seedling counts and biomass to bare seed when herbicide was not applied and higher seedling counts and biomass than bare seed when a double herbicide treatment was applied. Our results demonstrate that broader testing of HPPs with the application of both indaziflam and imazapic is needed, especially across wide climoedaphic field conditions.

Sustainable beef production is a growing concern worldwide, particularly in arid regions where limited natural resources availability and adverse environmental conditions pose significant challenges. This manuscript presents a comprehensive review of the potential of Criollo cattle breeds as an alternative for sustainable beef production in America. Criollo cattle, known for their resilience, hardiness, and adaptability to arid and semiarid environments, offer unique advantages in sustainable livestock production systems. Therefore, the use of criollo cattle and their crossbreds may be an alternative to face current and emerging challenges in beef production, which include a decrease in rangelands carrying capacity, adaptation to adverse environmental conditions, increase in diseases and parasites due to climate change, and diminished regional feed and forage production. This manuscript discusses the environmental sustainability of Criollo cattle production, including resource use efficiency, carbon footprint, and land management practices, providing insights into the potential ecological and economic benefits of these breeds. Also, it highlights the role of Criollo cattle in assisting organic and grass-fed beef producers in producing high-quality products using primarily forage-based diets. This approach can significantly enhance their organic or grass-fed certification. Criollo cattle have a unique flavor profile, which is highly sought after by consumers of organic and grass-fed beef. The meat of Criollo cattle produces omega-3, linoleic, and other fatty acids, which are beneficial to human health. Criollo cattle breeds are a valuable resource for enhancing resilience, promoting local biodiversity, producing good quality meat, and contributing to sustainable beef production in America.

Wildfire is an increasing concern throughout the world, with wildfires increasing in size, frequency, suppression cost, and loss of lives and resources. Targeted grazing has been suggested as a tool to establish and maintain strategic fuel breaks by reducing the fine herbaceous fuel load and subsequently fire behavior metrics. In a full factorial replicated experimental design, we evaluated the effect of domestic cattle grazing at two seasons (summer and fall) and two utilization levels (low and moderate) on fuel characteristics and fire behavior metrics in two big sagebrush (Artemisia tridentata Nutt.) communities. Shrub cover and herbaceous biomass before and after grazing were estimated in 2014 and 2015. Grazed and control plots were burned in late September 2015 under low fuel moisture conditions; flame height and fire rate of spread were measured. Cattle grazing reduced the herbaceous fuel load and grass height and increased herbaceous litter cover on the soil surface following the short-term grazing treatments. The more intensely plots were grazed also resulted in lower fuel loads than less intensely grazed plots. The season of grazing did not affect herbaceous fuel loads at the time of prescribed fire because utilization of grasses and forbs varied by season resulting in similar herbaceous biomass among both seasons of grazing at the time of the prescribed fire. Grazing was found to be an effective tool at altering herbaceous wildland fuels, which reduced fire behavior metrics when shrub cover was below 18%. Flame height was positively correlated with the amount of herbaceous vegetation, grass height, and annual grasses in the plant community at low shrub cover. However, at higher shrub canopy cover (>18%), cattle grazing for fuel reduction and alteration was limited due to low herbaceous biomass and the wildfire's potential to carry through the shrub canopy.