Grazing Intensity Influences Ground Squirrel and American Badger Habitat Use in Mixed-Grass Prairies

Ground squirrel (Spermophilus spp.) and American badger (Taxidea taxus) burrowing activities are ecologically important disturbances that contribute to the heterogeneity of prairie environments. These activities also have a strong impact on habitat suitability for many other grassland species. However, effects of cattle grazing intensity on ground squirrel and American badger burrows are not well understood. From 2006 to 2012 we evaluated effects of grazing intensity and vegetation type on American badger burrow occurrence and ground squirrel burrow abundance using a manipulative grazing experiment in Grasslands National Park of Canada, Saskatchewan. The study area consisted of nine 300-ha pastures at a range of stocking rates, from very low to very high for the region. Each pasture had 10 plots (six upland and four lowland) where vegetation and burrow surveys were completed. Burrow abundance and occurrence as well as vegetation structure were assessed for 2 yr prior to the introduction of cattle to this landscape in 2008, which followed at least 15 yr without livestock, and from 2009 to 2012, following introduction of livestock. Data were analyzed using generalized linear mixed models. In upland habitats, ground squirrel burrow counts increased with increasing grazing intensity and decreasing vegetation biomass; conversely, badger burrow occurrence increased with decreased stocking rates and increasing average litter cover and vegetation biomass. Abundance and occurrence of both ground squirrel and badger burrows in lowland habitats was relatively independent of grazing intensity or vegetation. Vegetation composition had little impact on ground squirrel or badger burrows. A range of grazing intensities may contribute to maintaining diversity of burrowing mammals in prairie environments.     

川西北高原鼠荒地危害程度分级及适应性管理对策

高原鼠兔和高原鼢鼠是青藏高原特有的食草型小动物,其啃食、掘洞、刈割、贮草行为对高寒草甸生态系统既具有破坏损伤系统的负面效应,也有利于维持和稳定系统的正面效应,这种益害转化完全取决于不同时间和空间尺度上的害鼠种群及其数量。通过对川西北的阿坝州、甘孜州和青海省果洛州的42个高寒草地样地的鼠类种群密度调查和已有文献的采集分析,明确了草原害鼠在高寒草地生态系统中的角色和作用,定义了鼠荒地的概念,对鼠荒地危害程度划分为轻度、中度、重度和极度4个等级;依据指标因子重要性排序,分级指标包含害鼠种群、植物群落和土壤养分3个主因子群;总洞穴数量、有效洞口数等11个单项因子;并对不同危害程度的鼠荒地提出了封育自然修复、人为干预修复、半人工草地改建和人工草地重建4种草原鼠害适应性管理策略,对于高寒草地生态系统草原害鼠适应性管理和害鼠灭除后二次发生防控具有指导意义。     

Ecological role of the giant root‐rat (Tachyoryctes macrocephalus) in the Afroalpine ecosystem

Rodents with prevailing subterranean activity usually play an important role in the ecosystems of which they are a part due to the combined effect of herbivory and soil perturbation. This is the case for the giant root‐rat Tachyoryctes macrocephalus endemic to the Afroalpine ecosystem of the Bale Mountains, Ethiopia. We studied the impact of root‐rats on various ecosystem features within a 3.5‐ha study locality dominated by Alchemilla pasture, which represents an optimal habitat for this species, in 2 periods of a year. The root‐rats altered plant species composition, reducing the dominant forb, Alchemilla abyssinica, while enhancing Salvia merjame and a few other species, and reduced vegetation cover, but not the fresh plant biomass. Where burrows were abandoned by root‐rats, other rodents took them over and A. abyssinica increased again. Root‐rat burrowing created small‐scale heterogeneity in soil compactness due to the backfilling of some unused burrow segments. Less compacted soil tended to be rich in nutrients, including carbon, nitrogen and phosphorus, which likely affected the plant growth on sites where the vegetation has been reduced as a result of root‐rat foraging and burrowing.     

The ranging behaviour and habitat use of rabbits on farmland and their potential role in the epidemiology of paratuberculosis

Grazing herbivores avoid grass swards contaminated with faeces as the ingestion of faeces is a common route of micro- and macro-parasite transmission. The recent novel finding that herbivores do not avoid grass swards contaminated with rabbit faeces suggests that disease risk posed to herbivores by rabbits is determined by rabbit ranging and excretory behaviour. Using as a case study rabbits and the risk Mycobacterium avium sub-species paratuberculosis (M. a. paratuberculosis) poses to cattle, the interaction between rabbits and grazing pasture was studied on an infected farm in the east of Scotland in spring and autumn 2000. Radio telemetry, burrow surveys and faecal pellet count data were collected on two areas (Areas 1 and 2) of the farm with different habitat mosaics, to study the potential effects of season and habitat on the spatial distribution of rabbits faeces and thus disease in the environment. Twenty one rabbits were radio tracked and a total of 902 fixes collected. Mean home range sizes (100% minimum convex polygons) were between 2.0 and 7.1 ha per rabbit per season. Home ranges were significantly larger in spring, and in Area 1 which had more moor and woodland and less rough pasture. Rabbits used rough pasture most in Area 1 and gorse scrub in Area 2. In both areas, significantly more burrows were located in gorse scrub than in any other habitat. Most faecal pellets were deposited on the moorland habitat of Area 2 in autumn. In habitats to which grazing livestock had access, the mean rate of faecal deposition was 8571 pellets per ha per day. The greatest risk of disease transmission occurred in habitats of poor grazing quality (e.g., gorse scrub) which were used by rabbits for burrowing and thus contained high concentrations of faeces. The findings of the study are discussed in relation to management practices aimed at reducing disease risk to livestock, including the fencing of scrub and the reduction of rabbit population size to prevent expansion of rabbit burrows from scrub into grazing pastures.     

Mojave desert tortoise (Gopherus agassizii) thermal ecology and reproductive success along a rainfall cline

Desert resource environments (e.g. microclimates, food) are tied to limited, highly localized rainfall regimes which generate microgeographic variation in the life histories of inhabitants. Typically, enhanced growth rates, reproduction and survivorship are observed in response to increased resource availability in a variety of desert plants and short‐lived animals. We examined the thermal ecology and reproduction of US federally threatened Mojave desert tortoises (Gopherus agassizii), long‐lived and large‐bodied ectotherms, at opposite ends of a 250‐m elevation‐related rainfall cline within Ivanpah Valley in the eastern Mojave Desert, California, USA. Biophysical operative environments in both the upper‐elevation, “Cima,” and the lower‐elevation, “Pumphouse,” plots corresponded with daily and seasonal patterns of incident solar radiation. Cima received 22% more rainfall and contained greater perennial vegetative cover, which conferred 5°C‐cooler daytime shaded temperatures. In a monitored average rainfall year, Cima tortoises had longer potential activity periods by up to several hours and greater ephemeral forage. Enhanced resource availability in Cima was associated with larger‐bodied females producing larger eggs, while still producing the same number of eggs as Pumphouse females. However, reproductive success was lower in Cima because 90% of eggs were depredated versus 11% in Pumphouse, indicating that predatory interactions produced counter‐gradient variation in reproductive success across the rainfall cline. Land‐use impacts on deserts (e.g. solar energy generation) are increasing rapidly, and conservation strategies designed to protect and recover threatened desert inhabitants, such as desert tortoises, should incorporate these strong ecosystem‐level responses to regional resource variation in assessments of habitat for prospective development and mitigation efforts.     

The stadium effect: rodent damage patterns in rice fields explored using giving‐up densities

Rodents are globally important pre‐harvest pests of rice. In Southeast Asia, rodent damage to growing rice crops is commonly concentrated towards the center of rice fields, away from the field edge, resulting in a clear pattern known as the “stadium effect.” To further understand this behavior of rodent pests and to develop recommendations for future research and management, we examined the relation between giving‐up densities (GUDs) and damage patterns. In Tanay, Luzon, Philippines, GUD trays containing pieces of coconut in a matrix of sand were placed at 4 different distances from the field edge to quantify the perceived risk of predation in a rice field pest, Rattus tanezumi. GUDs were recorded during a dry and wet season crop at the reproductive and ripening stages of rice. In addition, assessments of active burrows, tracking tile activity and rodent damage to the rice crop, were conducted in the dry season. GUDs were significantly lower in the center of the rice fields than on the field edges, suggesting that rodent damage to rice is greater in the middle of rice fields due to a lower perceived predation risk. Furthermore, this perception of predation risk (or fear) increases towards the field edge and was greatest on the rice bund, where there was no vegetation cover. We discuss the implications for rodent management and rodent damage assessments in rice fields. This is the first documented use of GUDs in a rice agro‐ecosystem in Asia; thus we identify the challenges and lessons learned through this process.     

玛曲高寒草甸高原鼠兔种群数量对植被调控措施的响应

本研究通过在玛曲县退化高寒草甸草原实施不同草地改良措施后,对高原鼠兔发生生境的适合度进行调查分析,以期揭示当地高原鼠兔发生机理,并为有效开展高原鼠兔的生态防治提供理论依据和技术支撑。于2010年5月至2010年7月,对玛曲县退化高寒草甸草原进行围封、补播、施肥、划破等12种不同草地改良措施,通过堵洞盗洞法监测高原鼠兔种群密度,并结合样方法测定植被等生境因子,探讨玛曲退化高寒草甸草原高原鼠兔发生生境的适合度。研究结果表明:与采用改良措施前相比,不同改良措施下有效鼠洞密度均表现出差异显著性(P<0.05)。所有草地改良措施均显著降低了有效鼠洞密度(P<0.05),且补播措施显著优于其他措施(P<0.05)。有效鼠洞密度与群落结构的相关性及逐步回归分析表明,有效鼠洞密度与草层高度呈显著的负相关(P<0.05),因而在高寒草甸,植物群落草层高度是决定鼠群密度的重要因子,而禾草类高度是决定草层高度的重要因素。两年的植被定向调控试验表明,在该区不同草地改良措施均能有效降低有效鼠洞密度,而补播禾草和增施有机肥,增加植物群落中禾草的比例,进而提高整体草层高度,可显著降低有效鼠洞密度(P<0.05)。因此提出“增加植物群落中禾草比例,治理高原鼠兔危害” 的生物防治模式。     

Discrimination of “grazing milk” using milk fatty acid profile in the grassland dairy area in Hokkaido

Milk produced by the grazing system, referred to as “grazing milk” contains many components required for human health. The milk fatty acid (FA) profile is strongly associated with the diet on the farms. In the present study, based on the FA profile of farmer's bulk milk, we determined how to discriminate between milk produced on grazing and on a confinement system. A field survey was conducted four times (grazing and confinement season) in the Konsen (29 farms) and Okhotsk (25 farms) area in Hokkaido. Farmer's bulk milk samples and details of feeding management were collected and the FA profile of milk was measured. Milk produced during the grazing season contained less C16:0 and cis‐9 C16:0, and more C18:0, cis‐9 C18:1, trans‐11 C18:1, cis‐9,12 C18:2, cis‐9,trans‐11 C18:2 and cis‐9,12,15 C18:3 than milk produced during the confinement season. Discrimination analysis using 16 FA revealed that almost all milk samples were discriminated correctly (confinement season: 90% correct and 10% borderline, grazing season: 88% correct, 9% borderline and 3% incorrect). For farmers that were categorized incorrectly and were considered borderline in the grazing season, the dependency on pasture was low compared with that for farmers correctly discriminated. Therefore, to claim “grazing milk”, a high dependency on pasture is required for grazing dairy farmers.     

Thermoregulatory value of cracking‐clay soil shelters for small vertebrates during extreme desert conditions

Deserts exhibit extreme climatic conditions. Small desert‐dwelling vertebrates have physiological and behavioral adaptations to cope with these conditions, including the ability to seek shelter. We investigated the temperature (T) and relative humidity (RH) regulating properties of the soil cracks that characterize the extensive cracking‐clay landscapes of arid Australia, and the extent of their use by 2 small marsupial species: fat‐tailed and stripe‐faced dunnarts (Sminthopsis crassicaudata and Sminthopsis macroura). We measured hourly (over 24‐h periods) the T and RH of randomly‐selected soil cracks compared to outside conditions, during 2 summers and 2 winters. We tracked 17 dunnarts (8 Sminthopsis crassicaudata and 9 Sminthopsis macroura) to quantify their use of cracks. Cracks consistently moderated microclimate, providing more stable conditions than available from non‐crack points, which often displayed comparatively dramatic fluctuations in T and RH. Both dunnart species used crack shelters extensively. Cracks constitute important shelter for small animals during extreme conditions by providing a stable microclimate, which is typically cooler than outside conditions in summer and warmer in winter. Cracks likely play a fundamental sheltering role by sustaining the physiological needs of small mammal populations. Globally, cracking‐clay areas are dominated by agricultural land uses, including livestock grazing. Management of these systems should focus not only on vegetation condition, but also on soil integrity, to maintain shelter resources for ground‐dwelling fauna.     

Are Droppings,Distance From Pastoralist Camps,and Pika Burrows Good Proxies for Local Grazing Pressure?

Grazing is regarded as one of the most important factors influencing rangeland ecosystems. Many previous studies have used indirect measures (proxies) of grazing intensity, such as the distance from congregation areas and the number of herbivore excreta, to estimate effects of grazing on vegetation parameters in rangeland ecosystems. However, little is known about how such proxies reflect the true grazing intensity, and if their suitability is consistent across landscape conditions. We measured grazing intensity based on the amount of plant ramets being grazed in 75 plots positioned across a rangeland landscape in central Tibet. Several grazing intensity proxies (distance from pastoral camp sites, number of yak dung patches (old and fresh), sheep and goat dropping piles, and pika (Ochotona curzoniae) burrows (active and abandoned)) were also measured in each plot. Regression models were used to examine the suitability of these proxies in predicting our measure of real grazing intensity. None of the examined proxies satisfactorily predicted real grazing intensity in our study system. The distance from camp sites was the best proxy for grazing intensity (P<0.001), but it explained only 30% of its variation. Fresh yak dung and active pika burrows explained only 10% and 3% of the variation in grazing intensity, respectively. The suitability of using proxies for grazing intensity did not significantly differ along landscape parameters (elevation, aspect directions, and slope angle) (P>0.05), except that the number of animal excreta and pika burrows functioned better as proxies at low, compared to high, elevation (P<0.05). Our results should be of concern since many studies use proxies to estimate effects of grazing on vegetation dynamics and ecosystem properties. We recommend awareness of potential limitations and suitability of proxies, when real grazing intensity is not measured.     

Dental microwear of sympatric rodent species sampled across habitats in southern Africa: Implications for environmental influence

Dental microwear textures have proven to be a valuable tool for reconstructing the diets of a wide assortment of fossil vertebrates. Nevertheless, some studies have recently questioned the efficacy of this approach, suggesting that aspects of habitat unrelated to food preference, especially environmental grit load, might have a confounding effect on microwear patterning that obscures the diet signal. Here we evaluate this hypothesis by examining microwear textures of 3 extant sympatric rodent species that vary in diet breadth and are found in a variety of habitat types: Mastomys coucha, Micaelamys namaquensis and Rhabdomys pumilio. We sample each of these species from 3 distinct environmental settings in southern Africa that differ in rainfall and vegetative cover: Nama‐Karoo shrublands (semi‐desert) and Dry Highveld grasslands in the Free State Province of South Africa, and Afromontane (wet) grasslands in the highlands of Lesotho. While differences between habitat types are evident for some of the species, inconsistency in the pattern suggests that the microwear signal is driven by variation in foods eaten rather than grit‐level per se. It is clear that, at least for species and habitats sampled in the current study, environmental grit load does not swamp diet‐related microwear signatures.     

Voles and weasels in the boreal Fennoscandian small mammal community: what happens if the least weasel disappears due to climate change?

Climate change, habitat loss and fragmentation are major threats for populations and a challenge for individual behavior, interactions and survival. Predator–prey interactions are modified by climate processes. In the northern latitudes, strong seasonality is changing and the main predicted feature is shortening and instability of winter. Vole populations in the boreal Fennoscandia exhibit multiannual cycles. High amplitude peak numbers of voles and dramatic population lows alternate in 3–5‐year cycles shortening from North to South. One key factor, or driver, promoting the population crash and causing extreme extended lows, is suggested to be predation by the least weasel. We review the arms race between prey voles and weasels through the multiannual density fluctuation, affected by climate change, and especially the changes in the duration and stability of snow cover. For ground‐dwelling small mammals, snow provides thermoregulation and shelter for nest sites, and helps them hide from predators. Predicted increases in the instability of winter forms a major challenge for species with coat color change between brown summer camouflage and white winter coat. One of these is the least weasel, Mustela nivalis nivalis. Increased vulnerability of wrong‐colored weasels to predation affects vole populations and may have dramatic effects on vole dynamics. It may have cascading effects on other small rodent–predator interactions and even on plant–animal interactions and forest dynamics.     

基于MapGIS和植被数量指标的啮齿动物群落模拟专家系统的设计与实现

选择鼠害频发的阿拉善荒漠区分布面积较大的红砂+泡泡刺生境、红砂+杂类草生境和白刺生境,以夹日法记录三种生境中啮齿动物种群相对数量,利用啮齿动物种群相对数量与荒漠区灌木和草本植物之间的依存关系建立专家模拟系统,分析三种生境的主要害鼠子午沙鼠、三趾跳鼠和小毛足鼠种群相对数量与植物群落因子间的动态关系,并以MapGIS为地理信息平台,借助VB程序语言设计工具,设计阿拉善荒漠区啮齿动物群落模拟专家系统,探索植物群落与啮齿动物群落的反馈动态变化,实现利用植物群落指标预测啮齿动物群落组分及其相对数量变化的目标,为鼠害防控提供依据。     

Effects of levonorgestrel‐quinestrol (EP‐1) treatment on Mongolian gerbil wild populations: a case study

Rodent pest population outbreaks occur frequently in grassland ecosystems in northern China. The Mongolian gerbil (Meriones unguiculatus) is a dominant pest rodent which is distributed across the semi‐desert grasslands of Inner Mongolia, China. In 2009, we studied the contraceptive effect of levonorgestrel‐quinestrol (EP‐1), concentration 50 ppm, on a wild Mongolian gerbil population. The one‐off contraceptive treatment was compared with a control group using a semi‐monthly live trapping method in the Ordos Semi‐desert Grassland Region of Inner Mongolia. The results show that juveniles were not recruited in spring in the treatment group. Ratios of juveniles in the control and treatment groups showed significant semi‐monthly differences from spring to summer (one‐way ANOVA, F_{2, 14}= 7.53, P < 0.05). Between both groups, annual fluctuations of juvenile and total population densities were significantly different respectively (F_{2, 14}= 4.64, P < 0.05; F_{2, 18}= 7.72, P < 0.05). The contraceptive EP‐1 delayed the normal reproductive pattern of Mongolian gerbil populations. This suppressed birth rates of gerbil populations, reduced their densities, and changed their age structures. The period of EP‐1 baiting should be extended but it could be an ideal method for controlling Mongolian gerbil populations during each breeding season.     

Habitat evaluation for outbreak of Yangtze voles (Microtus fortis) and management implications

Rodent pests severely damage agricultural crops. Outbreak risk models of rodent pests often do not include sufficient information regarding geographic variation. Habitat plays an important role in rodent–pest outbreak risk, and more information about the relationship between habitat and crop protection is urgently needed. The goal of the present study was to provide an outbreak risk map for the Dongting Lake region and to understand the relationship between rodent–pest outbreak variation and habitat distribution. The main rodent pests in the Dongting Lake region are Yangtze voles (Microtus fortis). These pests cause massive damage in outbreak years, most notably in 2007. Habitat evaluation and ecological details were obtained by analyzing the correlation between habitat suitability and outbreak risk, as indicated by population density and historical events. For the source‐sink population, 96.18% of Yangtze vole disaster regions were covered by a 10‐km buffer zone of suitable habitat in 2007. Historical outbreak frequency and peak population density were significantly correlated with the proportion of land covered by suitable habitat (r = 0.68, P = 0.04 and r = 0.76, P = 0.03, respectively). The Yangtze vole population tends to migrate approximately 10 km in outbreak years. Here, we propose a practical method for habitat evaluation that can be used to create integrated pest management plans for rodent pests when combined with basic information on the biology, ecology and behavior of the target species.     

Harmful and economic thresholds for rodent pests in the Alxa desert area under different grassland utilization patterns北大核心CSCD

The rodent damage threshold and the rodent economic threshold are indicators that must be clearly defined in the practice of grassland rodent prevention and control. Different grassland types or different utilization methods of the same grassland type have completely different values for these two indicators. The damage threshold is the population density of pests at which the grassland is obviously compromised, and the economic threshold is the population density at which further pest population increases will cause economic losses. The Alxa desert region is ecologically fragile, and rodents are endemic. This study selected continuous grazing areas and prohibited grazing areas in the desert area of Alxa Left Banner and from 2015 to 2019 to investigated the species and density of pests using the ‘mark and recapture’ method, together with sampling to investigate the aboveground plant biomass in the sample area in August. The measured rodent unit densities and their daily food intakes were used to estimate the amount of forage loss, and a regression equation was used to obtain a fitted relationship between the rodent density and the ratio of forage loss. It was found that: 1) The fitted curves for the ratio of pest density and forage loss in the continuous and prohibited grazing areas took the form of logistic three-parameter, S-shaped curves. 2) According to the regression equation, the damage threshold in continuous grazing areas was 26 standard rodent units·ha-1 and the economic threshold was 39.3 standard rodent units·ha-1. In prohibited grazing areas, the damage threshold was 33.2 standard rodent units·ha-1 and the economic threshold was 30.2 standard rodent units·ha-1. Thus, the economic threshold pest density of continuous grazing areas was slightly higher than that of prohibiting grazing areas. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Global parasite and Rattus rodent invasions: The consequences for rodent‐borne diseases

We summarize the current knowledge on parasitism‐related invasion processes of the globally invasive Rattus lineages, originating from Asia, and how these invasions have impacted the local epidemiology of rodent‐borne diseases. Parasites play an important role in the invasion processes and successes of their hosts through multiple biological mechanisms such as “parasite release,” “immunocompetence advantage,” “biotic resistance” and “novel weapon.” Parasites may also greatly increase the impact of invasions by spillover of parasites and other pathogens, introduced with invasive hosts, into new hosts, potentially leading to novel emerging diseases. Another potential impact is the ability of the invader to amplify local parasites by spillback. In both cases, local fauna and humans may be exposed to new health risks, which may decrease biodiversity and potentially cause increases in human morbidity and mortality. Here we review the current knowledge on these processes and propose some research priorities.     

基于物种周转揭示放牧对荒漠草原植物多样性的影响

放牧引起草原生态系统物种更替,进而调控群落植物多样性。然而,放牧过程中物种更替与植物多样性改变间具有怎样的联系,目前缺乏系统的研究。本试验在内蒙古荒漠草原放牧实验平台进行,对群落植物多样性进行了调查。研究发现：随放牧强度的增加,群落物种总数下降了28%～52%且物种组成发生了明显的分异;随放牧强度的增加,群落科的数目和多年生杂类草的物种数逐渐减少,一年生植物的物种数增加,同时群落Simpson指数和Shannon-Weiner指数等显著降低(P<0.05);随放牧强度的增加,物种损失率和周转率显著提高(P<0.05),但物种获得率无显著变化;放牧荒漠草原物种损失率和周转率与植物多样性指数间呈显著负相关关系(P<0.05)。本研究从物种周转的角度揭示了放牧荒漠草原植物多样性降低的驱动机制,为优化荒漠草原管理和利用提供科学支撑。     

Functional‐trait ecology of the plateau pika Ochotona curzoniae in the Qinghai–Tibetan Plateau ecosystem

Understanding a species' functional traits allows for a directed and productive perspective on the role a species plays in nature, and thus its relative importance to conservation planning. The functional‐trait ecology of the plateau pika Ochotona curzoniae is examined to better understand the resilience and sustainability of the high alpine grasslands of the Qinghai–Tibetan Plateau (QTP). The key functional traits of plateau pikas are their abundance and behavior of digging extensive burrow systems. Plateau pikas have been poisoned over a significant part of their original geographic distribution across the QTP, allowing comparison of ecological communities with and without pikas. Nearly all mammalian and avian carnivores, most of which are obligate predators on pikas, have been lost in regions where pikas have been poisoned. Most endemic birds on the QTP nest in pika burrows; when pikas are poisoned, burrows collapse, and these birds are greatly reduced in number. Due to the biopedturbation resulting from their burrows, regional plant species richness is higher in areas with pikas than without. The presence of pika burrows allows higher rates of infiltration during heavy monsoon rains compared to poisoned areas, possibly mitigating runoff and the potential for serious downslope erosion and flooding. Thus, the functional traits of plateau pikas enhance native biodiversity and other important ecosystem functions; these traits are irreplaceable. As plateau pikas are not natural colonizers, active re‐introduction programs are needed to restore pikas to areas from which they have been poisoned to restore the important functional ecological traits of pikas.