Rodent burrow network dynamics under human‐induced landscape transformation from desert to steppe in Kalmykian rangelands

Rodents play an important role in rangelands through the engineering of extensive burrow systems, which provides key habitats for many animal and plant species. We have analyzed the long‐term variation in the abundance and distribution of rodent burrows in grazing ecosystems of southern Russia (Kalmykia) under the landscape change from desert to steppe caused by the drastic reduction of livestock after the collapse of the USSR in the early 1990s. We conducted burrow surveys in the “desert” (1980) and “steppe” (2017) periods on 19 3‐km transects. We found considerable changes in burrow abundance and distribution, as well as evidence of desert habitat fragmentation and isolation caused by the expansion of tall‐grass communities. Burrows of the open‐dwelling diurnal ground squirrel (Spermophilus pygmaeus), the dominant and the keystone species during the “desert” period, almost completely disappeared from the rodent burrow network by 2017, indicating significant habitat loss. In contrast, the burrows of the folivorous social vole (Microtus socialis) which was rare in the 1980s, became abundant and ubiquitously distributed. The burrow density of the desert‐dwelling psammophilous midday gerbil (Meriones meridianus) decreased, while the distances between occupied patches increased, indicating desert habitat fragmentation and loss of population connectivity. Burrows of the folivorous tamarisk gerbils (M. tamariscinus) were recorded only sporadically in both 1980 and 2017. The observed changes in the rodent burrow network, the key component of grazing ecosystems, correlate with rodent species ecology and can have long‐term and important consequences for ecosystem functioning.     

草原的生态系统服务:III.价值和意义

连续综述了中国草原/草地生态系统服务价值的构成,草地生态系统服务的总价值,各类型草地的生态系统服务的价值。论证了草原/草地为中国提供了最大的生态系统服务价值,草地生态系统服务的生态价值远大于经济价值。论述了草地生态系统服务价值评估具有下列重要意义: 1. 指明了草地生态系统服务的具体项目及其不可代替性; 2. 确定了草地生态资本的价值; 3. 促进了环境成本核算和实现绿色GDP。文章在最后还讨论了草原/草地生态系统服务价值评估中存在的问题。     

1∶400万中国草地资源图的编制

本文介绍了1∶400万中国草地资源图的表现内容，最小图斑面积的确定，制图单位及分级，编制方法和步骤，草地类型分类方法和分类标准，草地品级与生产力综合评价方法与标准。重点阐述了编制小比例尺草地图的过程中，用中、大比例尺编图资料逐级缩小，通过编绘过渡图的方式，进行草地类型综合取舍，合并的原则和方法。阐明了按草地水、热条件和植被类型将全国草地划分为温性草甸草原类等17个草地类的定性、定量指标。     

库姆塔格沙漠植物群落类型及其多样性

采用线路调查法研究了库姆塔格沙漠植物群落类型及植物物种多样性。结果表明,库姆塔格的植被可划分为山前戈壁荒漠植被、沙漠植被和荒漠草甸植被3大类型,其中沙漠南部山前戈壁的荒漠植被17类,沙漠东缘和北缘的荒漠草甸植被12类,沙漠植被13类。因分布区域的差异,不同植物群落的物种多样性存在一定差异,南缘戈壁荒漠植物群落较稳定,物种多样性水平高,多样性指数平均为1.437,均匀度和优势度指数分别为0.824和0.302;沙漠植物群落物种组成稀少,群落稳定性差,多样性指数平均为0.725,均匀度指数为0.533;盐化草甸类植物群落多样性水平不高,群落相对较稳定,多样性、均匀度、优势度指数分别为0.804、0.807、0.547。戈壁荒漠植物群落随着气候环境干旱程度的加剧,多样性水平趋于减少,北缘植物群落多样性在中部地段明显升高,这与土壤结构组成有必然的联系,两条经度线上植物群落多样性变化与区域地形地貌及水文条件具有密切的关系。     

Effects of thinning on scatter‐hoarding by rodents in temperate forest

Deforestation and thinning are human activities that can destabilize the forest ecological system and, consequently, impact significantly on habitat and behavior of forest‐dwelling animals. This hypothesis was tested in Yugong in the Mount Taihangshan area by comparing the tracks of tagged seeds of Armeniaca sibirica. in sites of unthinned and thinned forests. Our results showed that: (i) the diversity of vegetation and rodents drastically reduced in sites with thinned forests, compared to unthinned sites; (ii) the amount of both removed and scatter‐hoarded seeds significantly declined in sites with thinned forests, compared with the unthinned sites; (iii) there was no significant difference observed in the distance of seed dispersal between the thinned and unthinned areas; and (iv) the thinning did not show a significant change to the model of cache size. These results suggested that the thinning of forests negatively influenced the species richness and food‐hoarding behavior of rodents. In addition, the results indicated that the weakened scattered‐hoarding might be disadvantageous to seedling recruitment and forest restoration.     

天山北坡荒漠草原土壤呼吸和生态系统呼吸对降水的响应

为揭示降水对天山北坡荒漠草原土壤呼吸和生态系统呼吸的影响,本实验以天山北坡荒漠草原为研究对象,通过测定3种模拟降水处理(CK,5 mm,18 mm,28 mm)下荒漠草原土壤呼吸速率和生态系统呼吸速率的变化特征.结果表明:不同降水处理下土壤呼吸速率和生态系统呼吸速率有明显的日变化趋势;3种降水处理下(28 m m,18...     

Context‐dependent responses of food‐hoarding to competitors in Apodemus peninsulae: implications for coexistence among asymmetrical species

Superior species may have distinct advantages over subordinates within asymmetrical interactions among sympatric animals. However, exactly how the subordinate species coexists with superior species is unknown. In the forests west of Beijing City, intense asymmetrical interactions of food competition exist among granivorous rodents (e.g. Apodemus peninsulae, Niviventer confucianus, Sciurotamias davidianus and Tscherskia triton) that have broadly overlapping habitats and diets but have varied body size (range 15–300 g), hoarding habits (scatter vs larder) and/or daily rhythm (diurnal vs nocturnal). The smallest rodent, A. peninsulae, which typically faces high competitive pressure from larger rodents, is an ideal model to explore how subordinate species coexist with superior species. Under semi‐natural enclosure conditions, we tested responses of seed‐hoarding behavior in A. peninsulae to intraspecific and interspecific competitors in the situations of pre‐competition (without competitor), competition (with competitor) and post‐competition (competitor removed). The results showed that for A. peninsulae, the intensity of larder‐hoarding increased and the intensity of scatter‐hoarding declined in the presence of intraspecifics and S. davidianus, whereas A. peninsulae ceased foraging and hoarding in the presence of N. confucianus and T. triton. A. peninsulae reduced intensity of hoarding outside the nest and moved more seeds into the nest for larder‐hoarding under competition from intraspecific individuals and S. davidianus. In most cases, the experimental animals could recover to their original state of pre‐competition when competitors were removed. These results suggest that subordinate species contextually regulate their food‐hoarding strategies according to different competitors, promoting species coexistence among sympatric animals that have asymmetrical food competition.     

Rodent control to fight plague: field assessment of methods based on rat density reduction

Rodents represent a serious threat to food security and public health. The extent to which rodent control can mitigate the risk from rodent-borne disease depends on both the effectiveness of control in reducing rodent abundance and the impact on disease epidemiology. Focusing on a plague-endemic region of Madagascar, this study compared the effectiveness of 3 methods: live-traps, snap-traps, and rodenticides. Control interventions were implemented inside houses between May and October 2019. Tracking tiles monitored rodent abundance. Rodent fleas, the vector involved in plague transmission, were collected. Rodent populations consisted of Rattus rattus and Mus musculus. In terms of trap success, we found that our live-trap regime was more effective than snap-traps. While all 3 control strategies appeared to reduce in-house rodent activity in the short term, we found no evidence of a longer-term effect, with in-house rodent abundance in treated sites comparable to non-treatment sites by the following month. Endemic flea, Synopsyllus fonquerniei, is a key plague vector usually found on rats living outdoors. Although we found no evidence that its abundance inside houses increased following control, this may have been due to a lack of power caused by significant variation in S. fonquerniei abundance. The presence of S. fonquerniei in houses was more likely when S. fonquerniei abundance on outdoor rats was higher, which in turn correlated with high rat abundance. Our results emphasize that control strategies need to consider this connectivity between in-house rat–flea populations and the outdoor populations, and any potential consequences for plague transmission.     

养分添加和降水变化对荒漠草原植物群落物种多样性和生物量的影响

本研究旨在探讨荒漠草原植物群落物种多样性及生物量对养分添加和降水变化的适应策略,以期为退化荒漠草原的恢复和管理提供理论基础。本试验在宁夏荒漠草原开展了养分添加和降水变化野外控制试验,通过测定植物群落物种数及生物量,研究养分添加和降水变化对荒漠草原植物群落物种多样性和生物量的影响。结果表明：养分添加显著降低禾草丰富度（P<0.05）;减少50%降水显著降低Shannon-Wiener指数和物种总丰富度,增加50%降水显著增加物种总丰富度（20.5%～28.2%）（P<0.05）;养分添加和增加50%降水显著提高植物群落盖度和生物量（P<0.05）;减少50%降水条件下,养分添加处理与不添加处理相比植物群落地上生物量显著提高（54.3%～75.6%）（P<0.05）;植物群落地上生物量与Shannon-Wiener指数和物种总丰富度呈显著正相关（P<0.05）。研究表明：减少50%降水条件下,养分添加能够缓解水分对荒漠草原植物生长的限制,其中氮磷钾添加缓解效果优于氮添加。     

Preliminary investigation on rodent–ectoparasite associations in the highlands of Tigray,Northern Ethiopia: implications for potential zoonoses

We studied associations between rodents and their arthropod ectoparasites in crop fields and household compounds in the highlands of Tigray, Northern Ethiopia. Ectoparasite infestation indices, such as percent infestation, mean abundance, prevalence and host preferences, were calculated for each taxon. In total, 172 rodents from crop fields and 97 from household compounds were trapped. Rodent species and numbers trapped from the crop fields and household compounds were Mastomys awashensis (Lavrenchenko, Likhnova & Baskevich, 1998) (88 and 44), Arvicanthis dembeensis (Ruppel, 1842) (63 and 37) and Acomys sp. (21 and 16), respectively. A total of 558 insects and acarids (belonging to 11 taxa) were recovered from the rodents trapped in the crop fields, and 296 insects and acarid (belonging to 6 taxa) from the rodents trapped in the household compounds. Approximately 66% of the rodents trapped from the crop fields and 47% of those trapped from the household compounds were infested with ectoparasites. Laelaps sp. (64.9%) and Xenopsylla sp. (20.6%) comprised the highest proportion of the ectoparasites recovered in the crop fields, and the same ectoparasites, but in reverse order, comprised the highest proportions in the household compounds (Xenopsylla [50.3%] and Laelaps sp. [29%]). Our study revealed that crop fields and household compounds in the highlands share similar rodents and several ectoparasites. Furthermore, at least 1 of the rodent species and some of the ectoparasites identified in this study were reported to have posed medical and veterinary threats in other parts of Ethiopia and neighboring countries.     

Monitoring to detect change on rangelands: physical,social and economic/policy drivers

Agents that can cause important changes in properties of biological communities are referred to as drivers. Drivers may be classed as physical, social and economic/policy, referring to their origin and mode of action. Physical drivers include environmental (weather, climate) and management (livestock grazing, prescribed burning) factors. Social drivers include attitudes and values of land mangers and the public. Economic/policy drivers refer to factors such as tax laws and environmental policies (including penalties and incentives). These drivers seldom operate independently, at similar scales, or in isolation from other drivers, and subtle interactions may confound both interpretation and response. While it is difficult to identify the impact of a specific driver on a specific biological property at a specific time, it is important to monitor changes in drivers to both predict likely impacts on ecological systems and design effective response tactics and strategies. Risk assessments, adaptive management analyses, or management by hypothesis require understanding linkages between environmental drivers and various management options on ecological properties of managed systems. Though our abilities to generate accurate predictions are currently limited, conceptual models of system response to drivers are improving. Continued incorporation and refinement of understanding and monitoring effects and interactions of different drivers will contribute to improvements in these predictive capacities. It is important to remember we are developing monitoring systems for the future, as well as for today.     

Serengeti III: Human Impacts on Ecosystem Dynamics

During a survey of seals in September and October 2009 at Gough Island, South Atlantic Ocean, we recorded goose barnacles (Lepas australis) attached to the pelage of two of the 12 elephant seals (Mirounga leonina) inspected and one of the seven vagrant Antarctic fur seals (Arctocephalus gazella) which were found amongst the resident Subantarctic fur seals (A. tropicalis). We also recorded a goose barnacle attached to a Northern rockhopper penguin (Eudyptes chrysocome moseleyi).     

Anthelmintic resistance in New Zealand: A perspective on recent findings and options for the future

A recent national survey on anthelmintic resistance in cattle and sheep in New Zealand indicated that the magnitude of the problem has increased from very low levels only a few years ago to disturbingly high levels now. There is a particular problem with multiple resistance to all three action families of anthelmintic currently available in Ostertagia (= Teladorsagia) spp in sheep, and to both macrocyclic lactones (ML) and benzimidazoles in Cooperia spp in cattle. The prevalence and extent of resistance indicate that all cattle farmers and most sheep farmers should now be using a combination anthelmintic on most occasions just to achieve effective control of all parasites. Despite this, the presence of resistant parasites has generally not been appreciated by the majority of affected farmers, possibly because most have not formally tested to determine the resistance status of nematodes on their farms.

Anthelmintics will remain the cornerstone of gastrointestinal nematode control in sheep and cattle for the foreseeable future but to ensure their continued effectiveness farmers need to be constantly aware of the need to maintain adequate reservoirs of unselected nematodes, i.e. worms in refugia, to minimise the expansion of the resistant population. High-risk practices in relation to selection of resistance need to be identified and avoided or at least their use limited. These include: treating adult animals where there is no identified need, moving newly- treated animals onto ‘clean’ pasture, and failing to effectively quarantine-drench bought-in animals. None of these are new concepts but many have not been adopted or practised. In particular, sheep farmers should endeavour to avoid treating ewes pre-lambing with long-acting anthelmintics. Farmers needs to negotiate a balance between achieving good parasite control and the sustainability of their control options.     

江苏省桑园叶蝉种类名录及一个新种的记述(同翅目:叶蝉科)

记述了采自江苏省桑园的叶蝉种类共7个亚科24个种,其中含1个新种(双叉铲头叶蝉Hecalus bifurcatessp.n.)、11个江苏新记录种,并厘定3个同物异名。新种模式标本保存在苏州大学昆虫标本室。     

Fertilization of southern tall grassveld of natal: Effects on botanical composition and utilization under grazing

Abstract

The long‐term effects of nitrogen, phosphate and lime on change in botanical composition and utilization under grazing of Southern Tall Grassveld of Natal are presented. Nitrogen, phosphate, lime and type of nitrogen affected botanical composition significantly. Generally, fertilization had the same effect on species composition score as heavy grazing. No change was observed in utilization by the grazing animal as nitrogen was increased, although a nitrogen X phosphate interaction was evident. Utilization by the grazing animal was not related to species composition score (SCS). Consequently, SCS alone cannot be used to predict grazing capacity.     

Sodium Chloride Effects on Seed Germination,Growth, and Water Use of Lepidium alyssoides,L. draba,and L. latifolium: Traits of Resistance and Implications for Invasiveness on Saline Soils

In the semiarid southwestern United States, long-term drought, soil salinity, and land-use intensification have increased the risk of invasive plants that threatens landscape biodiversity. Soil-related factors that regulate plant invasions are not adequately known. We evaluated the salinity responses of three invasive plant species during a 3-mo plant growth period in a greenhouse and during a 2–wk seed germination study in the laboratory. The species included the indigenous Lepidium alyssoides A. Gray var. alyssoides (mesa pepperwort) and the exotic, invasive L. draba L. (whitetop) and L. latifolium L. (perennial pepperweed). A NaCl solution at –0.2 MPa reduced germination of L. alyssoides by ≈ 20% and had no effect on germination of L. draba and L. latifolium, merely delaying their mean germination time by a day or less. Reductions in seedling dry matter production and evapotranspiration (ET) were observed following irrigation with NaCl solutions at –0.1 MPa and –0.2 MPa. However, on the basis of ET and total plant dry matter production under common experimental conditions, the salt resistance of these species greatly exceeded that of salt sensitive bean (Phaseolus vulgaris L.) and equaled or exceeded that of salt-resistant cotton (Gossypium hirsutum L.). Below-ground propagating structures giving rise to clonal shoots were observed for all Lepidium spp., consistent with other reports. The results indicate that vegetative propagule pressure and relatively high resistance to salinity at germination and seedling growth stages could contribute to the invasiveness of these species under saline conditions. A broader impact of the findings is in their application to the larger diversity of invasive species to aid in the understanding of soil salinity and how it may govern plant invasions. This dataset could improve risk assessment measures to favor biodiversity in rangelands and natural ecosystems of semiarid regions.     

Effects of a fast-burning spring fire on the ground-dwelling spider assemblages (Arachnida: Araneae) in a central South African grassland habitat

Fire is widely used as a management strategy in grasslands to maintain vegetation structure and improve grazing quality for large herbivores. The impacts of burning on invertebrates in South Africa remain poorly understood. A study was initiated in spring 2005 to determine the impact of a fast hot burn on ground-dwelling spider assemblages in a grassland habitat in the central Free State. Pitfall traps were set out at six sites in the reserve, with three sites each in the burnt and unburnt areas, to sample spiders over a 12-month period. A total of 5 253 spiders were collected, representing 33 families and 120 species. Spider abundance was significantly lower in the burnt (n = 1 956) than unburnt sites (n = 3 297), and burnt sites had, on average, considerably fewer species than unburnt sites. The dominant families in the burnt sites were Lycosidae (29.5%), Gnaphosidae (16.9%), Ammoxenidae (9.6%) and Zodariidae (5.7%), whereas Ammoxenidae (22.7%), Lycosidae (20.6%), Gnaphosidae (15.3%) and Amaurobiidae (10.2%) dominated the unburnt sites. Of the nine most abundant families collected, only Caponiidae were more abundant in the burnt than unburnt sites. Our data suggest that fast-burning hot spring fires cause a considerable initial post-fire decline in spider abundance, and have a negative influence on the abundance as well as the resistance of assemblages to disturbances other than fire (e.g. rain). However, most of the dominant families had abundances comparable to unburnt areas within a year post-burn.