Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
In Canada, plains bison (Bison bison bison) was assessed by The Committee on the Status of Endangered Wildlife in Canada as threatened. While bison are no longer at risk of demographic extinction, conservation programs remain challenged by the rarity of large populations and most bison are found in small, isolated, and confined herds. In this context, proper assessment of ecological carrying capacity is critical to inform habitat management and conservation efforts for species recovery. Although estimated food-limited carrying capacity is influenced by forage availability, forage requirements, and offtake proportion, it should also consider habitat selection by animals, especially inside confined settings to help avoid overgrazing. To support bison management in Grasslands National Park Canada, we integrated remote sensing, geographic information systems, and resource selection functions (RSFs) to examine variables that were potentially associated with bison habitat selection and return a comprehensive estimate of bison carrying capacity. Relevant variables were then integrated with estimates of forage availability using remote sensing and extrapolated to the bison containment scale. Factors of relevance to the RSFs include vegetation landscape units, slope, distance to water, fence, and road. In particular, bison selected for upland and sloped grasslands, which were characterized by the highest forage availability (1 064.5 kg ha–1 and 1 238.5 kg ha–1), while avoiding water in both growing and dormant seasons. The top-performing RSFs models in growing and dormant seasons were assessed using k-fold cross validation and achieved good predictive capacity (Spearman rank correlation [rs] ≥ 0.83, P < 0.01). Application of traditional clipping biomass samples and remote sensing derived variables is helpful in estimating annual forage quantity for bison (R2 = 0.75, P < 0.05). When accounting for bison resource selection, our model resulted in a carrying capacity estimate of about 0.0424 bison ha–1 or 764–770 bison (each requiring 12.2 kg forage/d), compared with 0.0587 bison ha–1 or 1 062 animals estimated when considering only the availability of forage. Such potential to increase carrying capacity to more than 1 000 individuals stresses the importance of testing management tools to shape bison grazing and increase forage utilization across a greater proportion of the 18 000-ha containment area. By improving our understanding of the interaction of this species with the mixed-grass prairie ecosystem, the integration of RSFs with estimates of carrying capacity can help inform conservation management of bison and multispecies at-risk habitat.
In Norway, cattle (Bos taurus) are released to large areas of boreal forest for summer grazing. To determine to what degree this practice challenges timber production and wildlife management, we need a better understanding of basic cattle ecology. What do cattle, typical grazers, feed on in a habitat typically used by browsers? We determined cattle's resource use and selection at three scales: habitat and microhabitat selection when foraging and diet selection. Boreal forest is dominated by grass-poor habitats, and despite their strong selection for grass-rich habitats, cows spent a lot of time in suboptimal habitats, like old bilberry (Vaccinium myrtillus) spruce (Picea abies) forest. However, they managed to find grass-rich habitat patches within those, selecting for patches with bentgrass (Agrostis spp.). Graminoids, mainly wavy hair-grass (Avenella spp.), tussock grass (Deschampsia), and true sedges (Carex spp.), made up the biggest part of the fecal samples. Woody plants, mainly willow (Salix spp.), Vaccinium spp., pine (Pinus spp.), and birch (Betula spp.), made up 9.4% ± 4.7% of the samples, a value lower than reported for other forest grazing cattle. Cattle avoided woody plants in their diet and selected for graminoids. They preferred deciduous over coniferous species. At these low stocking densities, the cows were grazers in this browser's habitat. Moreover, they selected rather on habitat and patch scale than for individual plants within a given habitat patch, considered typical for a grazer. Their grass-rich diet indicates little overlap with the diet of local wild ungulates, which are mostly browsers. Their aversion of spruce and selection for graminoids and deciduous trees indicates low conflict risk for browsing damages and even a beneficial weeding effect on trees planted for timber production.
A human-leopard conflict (HLC) is said to be any type of interaction that results in a mutually harmful effect on wildlife and humans. In recent decades, the scope and intensity of the HLC have increased due to the growth of the human population, changes in land use patterns, inefficient nature protection measures, and manipulation of nature. The study of habitats is considered vital to know their current situation and to think of solutions to solve emerging HLCs. Also, investigating the attitude of human local communities toward carnivores in the habitat where these HLCs is necessary for the management and protection of these species. Therefore, identifying the habitat needs of this valuable species is one of the essential needs of managers. Determining the distribution status of wildlife species and the status of their occupied habitats is important in managing wildlife and habitats. Social factors such as the attitude of human local communities are considered one of the most important factors affecting the HLC. To reach an effective management decision to reduce HLC, we investigated the factors affecting the attitude of human local communities toward this species in the conservation areas of Kohgiluyeh and Boyer-Ahmad Province. In this research, to investigate the attitude of human local communities, we used a questionnaire consisting of open-ended questions. According to the nature of the work, we selected 256 questionnaires related to the people who had the closest population center to the interviewed site. We interviewed the people who had the most knowledge and information about the local wildlife. The obtained results showed that the most damage to the property of human local communities is the attack on sheep and then domestic goats. The main reason can probably be due to the lack of main prey, as well as the entry of livestock into the range of the leopard's habitat in the slopes of protected areas or free areas. The results showed that knowledge of local communities about the leopard was effective in the positive attitude and interest in its presence, and the fear of the leopard did not cause a negative attitude and lack of interest in it. However, due to the increase of HLCs in recent years in Kohgiluyeh and Boyer-Ahmad provinces, economic losses may increase the retaliatory measures by the human local communities and endanger the survival of this species.
Unprecedented climatic and economic uncertainty, in particular severe drought, calls for management that can preclude some of the costs of reactionary measures for California ranchers. Increasing adaptive capacity has been widely recommended to address such uncertainty. Within this context, holistic management (HM), a decision-making framework marketed for ranchers, is of interest because it emphasizes systems-based thinking, maximizing flexibility and adaptability, ecological monitoring, soil health, and goal setting. Many HM ranchers use adaptive multipaddock (AMP) grazing management, characterized by the combination of moderate to high animal stock densities, fast rotations, pasture rest, iterative monitoring, and adaptive management. We interviewed a small group of AMP-HM ranchers in northern California to 1) examine how their on-the-ground implementation of AMP grazing relates to mental models for rangeland grazing as shaped by HM, including embedded decision-making processes, motivations, barriers, and catalysts; and 2) understand how AMP-HM ranchers believe the strategy helps them respond to increasing challenges. Our findings suggest that first, AMP-HM shifted ranchers' mental models through its emphasis on monitoring combined with increased interaction with land and animals, changing the ways interviewees saw and understood their management. Second, through its decision-making framework and trainings, AMP-HM increased ranchers' agency to operationalize new mental models. Together, these two facets culminated in a common suite of strategies that interviewees viewed as key to ranching profitably and sustainably. These include building flexibility into herd sizes and structures to increase temporal and spatial mobility, diversifying ranch enterprises to increase financial flexibility, building soil health, and reducing input costs—all of which have been recommended in rangeland management practices for decades. These findings suggest that AMP-HM, as an integrated package of rangeland management and decision-making practices, accompanied by education and training, may hold promise in helping ranchers strengthen their adaptive capacity and cope with uncertainty.
Semiarid grasslands of the Nebraska Sandhills provide critical ecosystem services and are an important forage resource for the local cattle industry. Over the past decades, warming and climate-related extremes have affected grassland production worldwide, which promotes the initiation of numerous grassland monitoring projects. Despite this, production trends for plant functional groups in the Sandhills regions in recent years have remained unknown. In this study, we analyzed plant biomass production of the Sandhills grasslands with a dataset collected over 15 yr from 2007 to 2021. Ungrazed total biomass and biomass of individual plant functional groups were assessed in grazing exclosures twice a year, in mid-June (for early season) and mid-August (for late season). This first paper reports our findings on total biomass and compositional changes of the three major plant functional groups, as well as trends in precipitation and temperature during the study period. A significant increasing trend (P < 0.05) was observed in temperature over time during the early season (April to mid-June), with a weak monotonic increasing trend (P= 0.07) during the full season (April to mid-August), whereas no significant pattern was reported for precipitation during the study, although it displayed complex within- and across-season patterns. The proportion of C3-grass biomass in total biomass increased (P < 0.05), while the proportion of C4-grass biomass decreased (P < 0.01). We did not observe any significant trends for forbs; however, the drought of 2012 resulted in up to a fivefold increase in the proportion of forb biomass the following year. These findings enhance our understanding of current patterns in grassland production and contribute to regional evidence on the response of plant functional groups to variability and extremes in intra-annual weather variables, which can improve our capability to perform adaptive grazing management in a similar semiarid grassland ecosystem.
Considering the nexus between public grazing lands and privately owned rangelands in the American West, some scholars argue that reduced access to public grazing allotments can result in subdivision or land conversion of private lands affiliated with livestock production—an argument presented as a choice between “cows or condos.” This argument has been applied to compensated permit waivers, a tool meant to reduce wildlife-livestock and other conflicts on public lands. We tested this “cows or condos” hypothesis by conducting semistructured interviews and a survey of permittees who have participated in a permit waiver, and through a property and records analysis of privately owned properties affiliated with 49 permittees who have accepted compensation to waive a federal grazing permit in the West since 1999. While we found no evidence of subdivision on private properties, common themes and mixed experiences arose from the producers we communicated with. Nearly every producer was experiencing untenable conflict on their grazing lease, most producers would have preferred to remain on their allotment if conflicts were reduced but were grateful they received compensation for waiving their permit, and many producers expressed concerns about the impacts of ongoing fragmentation of rangelands across the American West. The permit waiver presented difficulties for some producers, but for others the permit waiver was a catalyst for expanding their operation. Conflict with wildlife, agency restrictions, and exorbitant land values were cited by most producers as factors compromising their operation. We found no evidence to support the claim that compensated permit waivers are driving subdivision in the West; rather, many ranchers indicated the rapid development and fragmentation of Western landscapes is a major factor reducing the viability of livestock production.
Allometric models provide a rapid, nondestructive means for estimating aboveground biomass (AGB) of perennial grass species. In the absence of site-specific models, allometric relationships developed at other sites at other times are often used. This implicitly assumes that size-biomass relationships are highly robust. In this study, we assess the comparability of allometric relationships developed at two points in time (2005 and 2015) on different soils on a Sonoran Desert savanna in southern Arizona. We used peak growing season field measurements to develop single-species and multispecies regression models using basal diameter and height to predict the current year's AGB for seven perennial grass species. Basal diameter exhibited the strongest relationship with AGB among single-species (adjusted R2 = 0.54 to 0.87) and multispecies models (adjusted R2 = 0.73). Inclusion of height did little to improve biomass predictions. Our models generally underestimated observed 2015 AGB on the loamy site, whereas models developed in 2005 on a sandier site overestimated the 2015 AGB. Results suggest site-specific allometric models should be used when possible. However, in lieu of such models, relationships developed at other sites or at other times may be appropriate depending on the level of precision needed to address a specific research question.
Edward J. Raynor, Ashley Schilling-Hazlett, Sara E. Place, Juan Vargas Martinez, Logan R. Thompson, Melissa K. Johnston, Tamarah R. Jorns, Matthew R. Beck, Larry A. Kuehn, Justin D. Derner, Kimberly R. Stackhouse-Lawson
Enteric methane (CH4) emissions from cattle grazing extensive semiarid rangelands are largely unknown and represent a considerable knowledge gap for the beef cattle industry. Knowledge of baseline enteric CH4 emissions is beneficial for understanding the range of variability in individual animal emission production (g CH4 head [hd]–1 d–1) and emission intensity (g CH4 kg–1 average daily gain [ADG]–1). Here, we used field-based technology to determine enteric CH4 emissions from yearling steers grazing the North American shortgrass steppe in northeastern Colorado in midsummer 2022. Twenty-six animals were acclimated for 30 d (1–30 June) to the sampling equipment in the field before the measurement of emissions (1–31 July). Twelve (46%) yearling steers fully acclimated, with mean CH4 emissions ranging from 113.3 to 261.7 g hd–1 d–1 across the sampling period. Daily CH4 production values were 20% higher for steers (n = 9) from a local ranch compared with steers (n = 3) that originated from a mixed-grass prairie in south-central Nebraska (202.63 vs. 169.03 g CH4 hd–1 d–1). ADG of local steers was three times greater than their counterparts (0.54 vs. 0.18 kg hd–1 d–1), resulting in lower emission intensity (g CH4/ADG; emission intensity) from local steers compared with the naïve steers (237.6 vs. 418.5 emission intensity). In addition, we compared measured CH4 emissions with predicted emissions calculated using the Intergovernmental Panel on Climate Change tier 2 methodology; measured emissions were 31% greater than predicted for the local steers and 18% greater than steers from nonlocal steers. Results indicate that further research addressing grazing animal enteric CH4 emissions in extensive rangelands is needed. Further, efforts should be context specific for comparative efforts across rangeland ecosystems and animal origin to inform more accurate assessments of sustainability of grazing beef cattle related to greenhouse gas mitigation strategies.
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.
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.
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.
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 range-lands, 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.
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 footslope) 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.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere