Effect of cultivating croplands and grazing in arid grassland habitats on the conservation of melitaeine butterflies in a mountainous area in Northern China

In the study area (Yanjiaping Village, Hebei Province, China), grazing extensity varies at different locations, small and discontinuous croplands are imbedded in some arid grassland, which are habitats for the melitaeine butterflies, Euphydryas aurinia and Melitaea phoebe. These two species of butterfilies coexist in this area, in which grazing and cultivation are the main disturbances. Grazing and cultivation have a reciprocal effect on E. aurinia, rather than M. phoebe. We observed that E. aurinia preferred to occupy patches with moderate grazing and imbedded with small and discontinuous croplands, where E. aurinia also has high population density. The percentage of E. aurinia larval groups in the ribbings was significantly higher than that of M. phoebe, whereas larvae of both species tended to increase in recent years. Our data also showed that the population density and the patch occupancy rate of both E. aurinia and M. phoebe were the highest under moderate grazing. It indicates that cultivation of small and discontinuous croplands within the patch has a significant effect on the population density of both species of melitaeine butterflies. Thus, to artificially create or maintain semi-natural habitats, complemented by moderate grazing, might be an ecological strategy to conserve melitaeine butterflies effectively. Considering the distinct impacts of cultivation and grazing on the population distribution and dynamics of the two different species, human disturbance in the mountainous area might be strategically involved in proposing conservation plans for the target species in the future.     

两种共存网蛱蝶幼期的生命表研究

在河北省赤城县大海坨国家自然保护区内,从2002年到2004年应用生命表方法研究了在同一网络斑块中共存的金堇蛱蝶Euphydryas aurinia和大网蛱蝶Melitaea phoebe两个世代的幼期各阶段的死亡情况,目的是了解影响种群动态的重要因子,为它们的长期保育提供信息。结果表明,金堇蛱蝶幼期总累积死亡率都较小,两个世代分别为59%和72%; 而大网蛱蝶总累积死亡率较高,两个世代分别为89%和80%。影响大网蛱蝶死亡的最重要因子是放牧,两个世代与放牧相关的k值分别为0.559和0.167;尤其是在越冬后大网蛱蝶幼虫组聚集取食阶段,导致两个世代分别有50%和25%的幼虫组死亡。寄生蜂在大网蛱蝶小种群下也分别使两个世代4%和9%的5～6龄期幼虫以及13%和24%的蛹死亡。金堇蛱蝶死亡主要发生在越冬期,与越冬死亡相关的k值两个世代分别为0.073和0.199, 而寄主植物的质量影响越冬期幼虫组死亡; 寄生蜂则对金堇蛱蝶种群的调控作用极小,只有在2003～2004世代有4.0% 的越冬后幼虫被寄生和7%的蛹被寄生。影响两种蛱蝶种群动态的关键因子不同,采取的保护措施应有所不同。在春季减少源斑块内的放牧,对于以源-汇集合种群形式存在的大网蛱蝶种群恢复和增长十分必要; 而对以经典集合种群形式存在的金堇蛱蝶, 通过适当植被管理提高繁殖区域内寄主植物质量,可以提高越冬期幼虫组存活率,有利于其长期持续生存。     

Contrasting movement patterns in two species of chequerspot butterflies, Euphydryas aurinia and Melitaea phoebe, in the same patch network

Abstract.  1. Mark–release–recapture studies were conducted on two species of chequerspot butterfly, Euphydryas aurinia and Melitaea phoebe , in the same habitat patch network in Yanjiaping, a small basin in the Taihang Mountains, north-west of Beijing, China, in 2000.
2. Euphydryas aurinia tended to stay in the habitat patches and to move to neighbouring patches, whereas M. phoebe moved widely among patches in the entire network.
3. The parameters of the virtual migration model showed higher daily emigration propensity in M. phoebe and in E. aurinia males than in E. aurinia females, and significantly greater average daily movement distance in M. phoebe than in E. aurinia .
4. The results are consistent with the previous findings showing genetic structuring among local populations of E. aurinia but not among local populations of M. phoebe .
5. Based on the genetic and ecological results, it was concluded that E. aurinia has a classic metapopulation in the study area, whereas M. phoebe appears to have a source–sink metapopulation.
6. In 2000, when there was an overall increase in the abundance of the two species, the limited mobility of E. aurinia resulted in an increase in the average local population size, whereas the increase in the number of local populations in M. phoebe was due to its high mobility .     

栖息地质量对两种网蛱蝶集合种群结构和分布的影响

在河北省赤城县研究了栖息地质量对大网蛱蝶Melitaea phoebe和金堇蛱蝶Euphydryas aurinia两种网蛱蝶集合种群结构和分布的影响。这两种网蛱蝶在约10 km_²的区域内共存,成虫期的蜜源植物几乎相同,大网蛱蝶的发生峰期比金堇蛱蝶晚约一个月,两者只有不到一周左右的时间重叠。大网蛱蝶和金堇蛱蝶幼虫的寄主植物分别是: 祁州漏芦（菊科）和华北蓝盆花（川续断科）。蜜源植物的丰度与两种网蛱蝶的局域种群大小呈正相关;祁州漏芦的密度对大网蛱蝶的局域种群大小影响很大,金堇蛱蝶的局域种群大小则与其寄主植物华北蓝盆花的高度正相关;斑块内平均植被高度与两种网蛱蝶的局域种群大小均呈正相关,植物多样性、植物均匀性和植被盖度均与金堇蛱蝶的局域种群大小负相关,与大网蛱蝶的关系不大。同时分析了其他因子如斑块的坡向、坡度等的影响。主要结论是：1）幼虫寄主植物的不同和成蝶飞行峰期的分离允许两种网蛱蝶在这样一个小的斑块区域内共存;2）蜜源是重要的限制因子,并且受气候随机性的影响很大,蜜源的波动可以很好地解释网蛱蝶集合种群在年度间的动态变化;3）大网蛱蝶和金堇蛱蝶的飞行、食物搜寻能力的不同以及各自寄主植物的生物学特性、空间分布的不同决定了它们具有不同的集合种群结构： 金堇蛱蝶是经典的集合种群,大网蛱蝶是源-汇集合种群;4）斑块质量和昆虫行为共同决定了两种网蛱蝶的集合种群结构和分布。     

Influence of management on butterflies of rare grassland ecosystems in Germany

Traditional hay-meadows in the Alps and fens at the edge of the Alps are habitats for many rare and endangered butterfly species. Conservation efforts aim at preserving these species, but the biotopes depend on regular mowing, which in turn requires intensive financial support. The feasibility of substituting mowing of these sites by grazing is discussed and considered as a more cost effective management type which produces agriculturally valuable goods as well. In this study the butterfly fauna of mown and grazed sites were compared. Species composition, species number, and the occurrence of rare species under the two management types were in most cases rather similar for both grassland ecosystems. Nevertheless, there are hints that for single rare species this might not be true. Additionally, at one site, grazing intensity on a former hay-meadow was too high to preserve the species-rich community. Overall the results are encouraging: grazing does not have to be as detrimental as formerly thought, although details (compartments of pastures, intensity) still have to be confirmed. Experimental grazing management of aban-doned grasslands of the studied types should be started.     

天山北坡不同海拔梯度山地草原生态系统地上净初级生产力对气候变化及放牧的响应

以天山北坡三工河流域为例,利用改进后的Biome-BGC模型分别模拟了仅气候变化（Clm）、气候变化与放牧联合作用（ClmGra）下研究区不同海拔梯度3种山地草原生态系统（低山干旱草原,LAG;森林草甸草原,FMG;高寒草甸草原,AMG）1959—2009年地上净初级生产力（Aboveground Net Primary Production,ANPP）的动态,并通过假设27种放牧强度情景（0—8 羊/ha）模拟了其ANPP随放牧强度增加的变化趋势。近50年气候变化致使研究区各海拔梯度草原生态系统ANPP整体均呈上升趋势,但在放牧联合作用下,不同草原类型ANPP变化趋势差异显著;放牧导致FMG和AMG的ANPP呈下降态势,分别减少30.0%和33.2%,对比之下,由于1980前较低放牧强度促进了LAG的ANPP,放牧导致其ANPP整体增加1.3%。随着放牧强度增加,LAG的ANPP呈先增后减趋势,且在干旱年份最为显著;而FMG和AMG的ANPP呈显著非线性递减趋势。这些结果表明,近50年气候波动可能有利于中亚干旱区山地草原生态系统生产力的提高,但日益增强的放牧活动导致其净初级生产力显著降低;放牧对FMG与AMG生产力的负面效应随放牧强度增加而增强,但适度放牧可能促进LAG净初级生产力,尤其在干旱年份。     

放牧和模拟增温对藏北高寒草地植物群落特征及生产力的影响

气候变化和放牧活动对草地植物物种多样性和生产力具有重要影响。为探索藏北高寒草地植物物种多样性和生产力对增温、放牧及其交互作用的响应, 于2011年在藏北高原开始建立增温实验平台, 2016年起增设放牧、增温+放牧实验, 连续2年(2016-2017年)观测了植物群落特征、群落组成、生产力和物种多样性。结果表明, 增温和放牧对高寒草地植物高度和净初级生产力具有显著交互作用。在放牧条件下, 增温对植物高度无显著影响; 但在不放牧条件下, 增温却显著增加了植物高度。在放牧条件下, 增温对净初级生产力的影响存在年际差异, 2016年增温对生产力无显著影响, 2017年增温显著降低了植物净初级生产力; 但在不放牧条件下, 增温对植物净初级生产力无显著影响。增温和放牧对高寒草地植物物种丰富度、盖度、重要值及多样性均无显著交互作用。植物盖度在增温和放牧条件下显著降低, 杂类草物种比例显著增加, 但物种多样性均无显著变化。研究表明, 增温和放牧显著改变高寒草地群落结构。未来气候变化条件下, 放牧活动加剧有可能导致高寒草地生产力降低。     

Habitat preference of the striped legless lizard: Implications of grazing by native herbivores and livestock for conservation of grassland biota

Across the globe, many species of reptile are threatened with extinction, with changes in grazing pressure as a significant factor in their decline. Few studies have investigated the role of native herbivores, yet studying natural grazers may provide insight into natural grazing regimes, not apparent in studies of domestic livestock. In this study, we investigate the habitat requirements of a threatened Australian grassland reptile, the striped legless lizard, Delma impar, in grasslands grazed by a native herbivore, the eastern grey kangaroo Macropus giganteus. Delma impar appears sensitive to habitat change resulting from altered grazing intensity, but a lack of information hinders implementation of appropriate grazing regimes. To address this gap, we investigated habitat preferences of D. impar at multiple spatial scales across a grazing gradient. We found that the occurrence of D. impar was not affected by the size of grassland remnants, but was negatively related to the density of native grazers. This result was likely a consequence of the negative effect of high grazing intensity on grass structural complexity, as the probability of encountering a D. impar was positively related to grass structural complexity at the fine scale (1 m²). We recommend that conservation efforts should avoid high intensity grazing (equivalent to > 1.3 kangaroos/ha), yet ensure enough grazing disturbance is maintained to promote the formation of complex grass structures. We also recommend that small floristically degraded and fragmented grassland habitat should be included in conservation efforts. These recommendations will likely benefit a number of faunal species in grasslands grazed by domestic and native grazers. Importantly, our data highlight the need for managing grazing regimes, even in environments dominated by native herbivores.     

An experimental study of the impact of seasonal sheep grazing on formerly fertilized grassland

Abstract. The effects of grazing upon the composition of a grassland were examined in a replicated grazing experiment with sheep over eight years. Grazing was controlled to produce two levels of grazing in each of winter, spring and summer, combined in a 2×2×2 factorial experimental design. Particular species were either increased or decreased by winter grazing while, in general, dicotyledonous species were favoured by grazing in both winter and spring. A model fitting the main effects of grazing in three seasons showed the importance of grazing in winter and spring to achieve sward diversification.     

Long‐term stock grazing management in Travelling Stock Reserves and influence on conservation values

We examined the nature of long‐term grazing management implemented in 51 Travelling Stock Reserves (TSRs) in the Albury region, and investigated potential relationships between grazing intensity and conservation values. In general, grazing intensities in most TSRs decreased over the 22 year study period. Most TSRs were lightly grazed (density = 1.1 DSE/ha/year), and stocked for <2 months per year, but some were much more heavily grazed. Spring grazing intensity was found to be negatively associated with TSR conservation values. Our results suggest that grazing management aims to achieve both production and conservation outcomes are not necessarily exclusive to each other.     

藏北高寒草地植被和土壤对不同放牧强度的响应

放牧压力在时间和空间的不均衡分布导致局部土地过度利用和生态退化,然而当前对放牧强度的量化多采用替代性指标或对照试验,缺乏直接监测数据,也缺乏不同草地类型对放牧强度变化的响应差异性研究。以西藏自治区那曲市为研究区,利用佩戴式GPS牛羊定位器构建高精度放牧轨迹数据集模拟放牧强度,构建栅格尺度放牧强度空间分布和划分方法,结合草地群落样方调查,通过Duncan法（Duncan''s multiple comparative analysis）进行多重比较分析,探究自由放牧模式下高寒草甸和高寒草原两类区域植被和土壤对不同放牧强度的响应方式及差异性。本研究可为放牧行为环境效应监测提供新思路,并根据不同草地状况因地制宜提出放牧优化管理策略,助力高寒传统牧区的可持续发展。主要结论有：1）随着放牧强度的增大,高寒草原地上生物量先升高后降低,高强度放牧对高寒草原植被的影响大于高寒草甸。2）高放牧强度下,高寒草原土壤水分显著高于中低强度,高寒草甸土壤容重显著低于低强度。可能原因是放牧压力多集聚于水源附近。高寒草原区土壤的砂粒含量随放牧强度的增大而增加。放牧强度的增大导致草甸上层土壤有机质增加,草甸下层、草原上层、草原下层土壤有机质先增加后减小。草甸上下层土壤全磷含量在低放牧强度下显著低于中高强度。3）植被土壤变化受到自然因子和放牧活动的共同影响。高寒草甸更加耐牧,高强度放牧对高寒草原的负面影响更大,而中度放牧有利于草地尤其是高寒草原的放牧利用。4）放牧生态系统是一个环境-植物-家畜自适应系统。在放牧管理中不能仅通过控制载畜量缓解草地超载,还需要综合考虑生态系统的弹性及各营养级的适应性,合理配置放牧强度,控制季节性超载和局部超载。     

Effect of continuous v. daytime grazing on feed intake and growth of sheep grazing in a semi-arid grassland steppe

In the Inner Mongolian steppe, China, sheep generally graze during daytime and are kept in yards overnight. Hence, nutrients are not returned to the grassland, which might reduce its long-term productivity. Furthermore, the restricted grazing time may limit forage intake and thus the performance of sheep. The aim of this study was therefore to evaluate the impact of continuous 24-h grazing (CG) v. the common daytime grazing (DG) on herbage mass (HM), feed quality, feed organic matter intake (OMI) and live weight gain (LWG) of sheep in the Inner Mongolian steppe. Experiments were carried out from July to September, between 2005 and 2007 on two 2-ha plots per grazing treatment. Each month, the external faecal marker titanium dioxide (TiO(2)) was orally administered to six sheep per plot on 10 consecutive days. Faecal grab samples were obtained from day 6 to 10 and analysed for CP concentrations to estimate digestibility of organic matter (dOM). Faecal TiO(2) concentrations were used to determine the total faecal output and hence OMI of sheep. Concomitant to faeces collection, HM and quality, as well as LWG of the animals were measured. HM and herbage quality did not differ between treatments. However, as the season progressed, concentrations of NDF, ADF and ADL increased, whereas HM and CP concentrations declined. HM and herbage quality parameters differed between years according to the annual precipitation. dOM was similar in CG (0.577) and DG (0.572) sheep, but it decreased from July (0.583) to September (0.558) and differed between years. Accordingly, the OMI of sheep was similar for both treatments across the entire grazing season and all study years. Although mean LWG differed between months and years, it was identical in CG (101.5 g/day) and DG sheep (101.8 g/day). Additional time on pasture during night does not increase feed intake or animal performance. Positive effects of a nutrient reflux on grassland productivity and herbage quality when animals remained on the plots overnight were not found, most likely because of the fact that sheep crowded together in one corner of the plots during darkness and faecal and urinary excretions were thus not evenly distributed across the entire pasture. Considering the risk of animal theft as well as the importance of sheep manure as fuel, the common penning of sheep at night seems to be an adequate management practice for pastoralists in the Inner Mongolian steppe.     

Genetic differentiation within metapopulations of Euphydryas aurinia and Melitaea phoebe in China

We analyzed genetic differentiation within metapopulations of two species of checkerspot butterfly, Euphydryas aurinia and Melitaea phoebe, in China. To generate genetic information, we used a new molecular technique, DALP – direct amplified length polymorphism. AMOVA results showed that most of the variation occurred among individuals within local populations of both E. aurinia and M. phoebe. However, while there was differentiation among local population in E. aurinia (P < 0.001), there was no subdivision in metapopulation of M. phoebe (P = 0.210). This is consistent with the behavior of M. phoebe adults being more dispersive than E. aurinia. Within the M. phoebe metapopulation, three neighboring patches were always occupied during the observation period (1998–2000). In addition, the number of individuals in these three populations accounted for the majority of M. phoebe larvae, and hence we conclude that the M. phoebe metapopulation might exist as a source-sink metapopulation. On the other hand, the E. aurinia metapopulation is an example of a classical metapopulation. Therefore, the conservation management of these two species should reflect these differences.     

放牧强度对内蒙古典型草原糙隐子草功能性状的影响

研究糙隐子草株高、丛幅等11个性状指标对不同强度放牧(不放牧;5、7月两次放牧;全生长季5次放牧)的响应.结果表明:以不放牧为对照,经过连续5年的放牧处理,糙隐子草的生殖枝数、株高、茎质量、比叶面积和总叶面积显著降低,5、7月放牧处理各指标降幅分别为61.7％、21.5％、33.3％、21.6％、26.7％,全生长季放...     

Response of a rare herb (Trioncinia retroflexa) from semi‐arid tropical grassland to occasional fire and grazing

Trioncinia retroflexa (Asteraceae) is a rare perennial herb endemic to Dichanthium‐dominated grasslands on basaltic soils in central Queensland. Trioncinia lives for approximately 5 years and some seed remains viable in the soil for at least 18 months. Population densities increased sixfold over 4 years, coinciding with recovery during a period of above‐average rainfall after a 4‐year drought preceding this study. The species’ lifespan, which can exceed 5 years, coupled with its extended seed‐bank viability ensures that populations can endure drought despite low levels of seedling recruitment. The restricted occurrence of the species to spasmodically grazed stock routes provides evidence that Trioncinia is sensitive to the continuous grazing that typically occurs in paddocks. The hypothesis that the species requires occasional disturbance for survival was experimentally tested. Recruitment was depressed with burning and inflorescence production enhanced with both burning and simulated intense spasmodic grazing after the first application of treatments. However, these effects were not evident after a second application of the treatments and there were no significant effects of treatment on population densities at the completion of the 4‐year experiment. Although not requisite, sporadic dry‐season grazing and burning of these areas would appear to be compatible with the survival of Trioncinia. This project highlights the value of stock routes for rare plant conservation.     

放牧对草原植物功能性状影响研究进展

植物功能性状的表达和植被环境适应性相关,植物功能性状之间的权衡变化体现了植物在放牧胁迫下资源的重新整合和获取.本文总结了放牧干扰下植物功能性状表达的差异性,着重将放牧干扰与植物功能性状相结合,介绍了植物功能性状的变异来源是植物遗传特征与环境过滤相互协调的结果,归纳了放牧对植物营养性状、繁殖性状的影响,以及植物可以通过调...     

Complexity of species conservation in managed habitats: interaction betweenMaculinea butterflies and their ant hosts

Europe's five species ofMaculinea butterfly are examples of endangered species adapted to live in traditional, cultural landscapes. All are threatened with extinction in Western Europe because of recent changes in land use. This is illustrated by an historical account of the extinction of the BritishMaculinea arion populations, despite many conservation attempts. It is shown how the failures proved to be due to ignorance of the key factor forM. arion, its specialization on a single ant host,Myrmica sabuleti. A brief account is given of research that shows how each of the five species is similarly dependent upon a separate hostMyrmica ant species and how each has an interesting and rare specific parasitoid. Steps for the practical conservation of existingMaculinea populations including the obligation, under the Bern Convention, to re-establish nationally extinct species are outlined. The procedure and problems involved in re-establishment are illustrated with reference to the successful programme forM. arion in Britain. The best way of ensuring robust populations ofMaculinea butterflies is to manage habitats to optimize the density and distribution of the required species ofMyrmica host and, secondarily, the distribution of the larval food plant. The value of single species conservation in cultural habitats is discussed. It is concluded that this is possible to achieve and that other rare organisms also often benefit, but only when conservation measures are based on the results of detailed autecological research.     

划区轮牧中不同放牧利用时间对草地植被的影响

对比研究了划区轮牧中不同时间的放牧利用对各小区的植被状况的影响。结果表明 ,在固定放牧时间长度的情况下 ,早放牧小区的草群结构比晚放牧的小区受到的影响大。家畜对早放牧小区的牧草利用率高于晚放牧的小区 ,草地生产力则表现出相反的趋势。对于可利用牧草营养 ,早放牧的小区可提供较多的粗蛋白。在生产实践中 ,要灵活应用划区轮牧制度 ,对不同时间放牧利用的各小区要根据草地的实际情况来确定其具体的放牧时间长度 ,在不同的年度也要按不同的顺序来轮换放牧 ,兼顾到草地的可持续利用与家畜生产。     

放牧胁迫下沙质草地植被的受损过程

通过在科尔沁沙地为期5a的放牧试验,分析探讨了过牧条件下沙质草地植被的受损过程。试验结果表明,持续过牧下,植被严重受损。其基本过程是,随着植物茎叶被大量啃食,草地群落盖度、高度和地上现存生物量急剧下降,连续过牧5a已分别较禁牧区低82．1％、94．0％和97．9％。但草地的净初级生产力(现存生物量 家畜采食量)下降幅度较小,第5年仍为禁牧的49．5％,而其被家畜啃食的净牧草量与现存生物量的比值高达23：1,远远高于中牧和轻牧的1：1和0．3：1水平。过牧下,物种丰富度、植物多样性和均匀度也急剧下降。第5年分别为禁牧区的35．0％、29．8％和45．9％,家畜喜食的多年生和1年生植物被不喜食的1年生植物所取代,劣质牧草比例达到86％,草地生活型趋于简单。随着地上净初级生产力的下降,地下生物量也趋于下降．根层分布浅层化。在这一退化过程的后期,由于地面裸露,风沙活动强烈,植被退化进程加速,这和草甸草原植被放牧所引起的退化存在明显区别。轻牧和中牧对草地群落盖度、高度和现存生物量也有很大影响．但试验期内对草地物种丰富度和植物多样性尚未产生明显影响。     

Rainfall and the interaction of microclimate with larval resources in the population dynamics of checkerspot butterflies (Euphydryas editha) inhabiting serpentine grassland

Summary The interaction of host plant phenology and microclimatic heterogeneity was examined to determine its role in the population dynamics of checkerspot butterflies, Euphydryas editha, inhabiting serpentine grassland in California's outer Coast Range.Within the 2–3 hectares inhabited by a population of E. editha (Jasper Ridge Area H), microclimatic differences resulting from topographic heterogeneity largely determine the temporal and spatial pattern of senescence of the larval host plants, Plantago erecta and Orthocarpus densiflorus. Survival of larvae from hatching to diapause is extremely low as a result of unpredictable variation in the timing of larval development relative to the timing of host plant senescence, both of which are mediated by microclimatic patterns. During this study, population H declined to near extinction as a result of two consecutive years of record rainfall that apparently disrupted the tenuous temporal relationship between larval development and plant senescence. Retarded development of post-diapause larvae led to a late and extended flight season and delayed egg production; this in turn resulted in massive mortality of pre-diapause larvae due to starvation because host plant senescence occurred before larvae became large enough to enter diapause. Adult population size the following spring was the smallest in 25 years of study. This work emphasizes the importance of microclimatic heterogeneity for understanding population-level processes in small ectothermic animals and underlines the potential importance of such heterogeneity in the establishment of reserves designed to protect such animals