Eliciting and integrating expert knowledge to assess the viability of the critically endangered golden sun‐moth Synemon plana

The critically endangered golden sun‐moth Synemon plana occurs in urban fringe areas of southeastern Australia that are currently experiencing rapid and extensive development. The urban fringe is a complex and uncertain environment in which to manage threatened species with the intersection of fragmented natural habitats, built environments and human populations generating novel, poorly understood interactions. In this context, management frameworks must incorporate ecological processes as well as social considerations. Here, we explore how biodiversity sensitive urban design might improve the fate of the golden sun‐moth, and threatened species generally, in urban fringe environments. We: (i) developed an expert‐informed Bayesian Belief Network model that synthesizes the current understanding of key determinants of golden sun‐moth population viability at sites experiencing urbanizing pressure; (ii) quantified the nature and strength of cause‐effect relationships between these factors using expert knowledge; and (iii) used the model to assess expectations of moth population viability in response to different combinations of management actions. We predict that adult survival, bare ground cover and cover of resource plants are the most important variables affecting the viability of golden sun‐moth populations. We also demonstrate the potential for biodiversity sensitive urban design as a complementary measure to conventional management for this species. Our findings highlight how expert knowledge may be a valuable component of conservation management, especially in addressing uncertainty around conservation decisions when empirical data are lacking, and how structured expert judgements become critical in supporting decisions that may help ameliorate extinction risks faced by threatened species in urban environments.     

Phylogeography and population history of the endangered golden sun moth (Synemon plana) revealed by allozymes and mitochondrial DNA analysis

A combination of allozyme and mitochondrial DNA markers were used to determine the contribution of recent and ancient causes of patterns of genetic variation within and among 46 populations of the endangered golden sun moth, Synemon plana. Allozyme analysis grouped the 46 populations into 5 major genetic clusters that corresponded closely with geographic location following a classic isolation-by-distance model. Phylogenetic analysis of 14 mtDNA haplotypes revealed two reciprocally monophyletic groups. One of these groups (containing 4 geographically distant populations) was clearly identified by allozyme analysis and represents a distinct evolutionary unit. The remaining 4 allozyme groups were not distinguishable by mtDNA analysis. The evidence suggests that the populations within these groups derived from a small founding population that underwent rapid demographic expansion in ancient times. This was followed by more recent population bottlenecks resulting from habitat fragmentation associated with the widespread introduction of agriculture into the region. The generally low levels of allozyme and nucleotide diversity within these populations support this hypothesis. This revised version was published online in July 2006 with corrections to the Cover Date.     

More than an empty case: a non invasive technique for monitoring the Australian critically endangered golden sun moth, Synemon plana (Lepidoptera: Castniidae)

Monitoring programs for butterflies and moths are focused on the adult stage, rarely considering other life stages. Transect-based counts of adults and searches for empty pupal cases have been suggested as standard monitoring protocols for the critically endangered golden sun moth Synemon plana in Australia. To date, surveys and monitoring have focused only on counts of adults. However, undertaking such counts is constrained by the short adult life of the species (1–2 days), and the fact that prevailing weather conditions can seriously influence detectability. We tested whether empty pupal cases of S. plana can be used to supplement the monitoring of adults and whether this technique can be undertaken by citizen scientists. Volunteers from Canberra (Australia) collected 650 pupal cases from 11 grassland areas. The cases were found in native grasslands and in grassland comprised entirely of the exotic Chilean needle grass (Nassella neesiana). Pupal cases of S. plana were found to be durable, with most persisting in the field for greater than 3 weeks after first sighting, and exhibited a male biased sex ratio. This study demonstrates that detection of empty pupal cases provides a potential additional tool to monitor S. plana that is not dependent on the restrictions of prevailing weather conditions and time of day, and can be undertaken by citizen scientists.     

Moths in fragments: insights into the biology and ecology of the Australian endangered golden sun moth Synemon plana (Lepidoptera: Castniidae) in natural temperate and exotic grassland remnants

The conservation and management of endangered species requires an adequate understanding of their biology and ecology. Although there has been an increasing appreciation in Australia of the need for greater efforts to conserve insects, there is only limited information available that can be used to underpin conservation efforts. The endangered golden sun moth, Synemon plana (Lepidoptera: Castniidae) is a flagship species endemic to natural temperate grassland in south-eastern Australia. Most populations of this species are at considerable risk from habitat loss, weed invasion and inadequate management. Despite the considerable knowledge that exists about the species biology and ecology, efforts to improve the species conservation status are hampered because there are still critical gaps in our understanding of the species’ natural history. In particular, the ecology of the larvae is not known. Our study examined the abundance, population structure and reproductive biology of the moths in a broad sample of both natural temperate and exotic grassland remnants in and near Canberra in the Australian Capital Territory (ACT) in south-eastern Australia. The results fill critical gaps in the knowledge needed to achieve effective conservation management. From our findings, it is clear that the species inhabits grasslands dominated by a mixture of native wallaby grasses (Rytidosperma spp. (formerly Austrodanthonia)) and spear grasses (Austrostipa spp.). In contrast to earlier suggestions that S. plana is entirely confined to natural temperate grassland, mature and immature life stages of the species were also present in grasslands comprised entirely of the exotic Chilean needlegrass (Nassella neesiana). Most of the S. plana populations surveyed in the ACT were characterised by low relative abundance with only very few large populations being recorded. The conservation of exotic grasslands as substitute habitat for S. plana is discussed and suggestions regarding future monitoring and research of the species are provided.     

Spatial pattern changes in aboveground plant biomass in a grazing pasture

Using gamma distribution and spatial autocorrelation, it was demonstrated that plant biomass per unit area of a pasture grazed by cattle exhibited two kinds of spatial heterogeneity: small-scale heterogeneity caused by grazing and large-scale heterogeneity caused by topography, land aspect, etc. For each of the 10 measurement times from May to August, 100 quadrats 50cm × 50cm were arranged along a straight line 50m long in a pasture, and the plants within the quadrats were harvested at the height of 3cm above the ground surface to measure the dry weight. The data were aggregated into frequency distributions, and gamma distribution and the parameter values were estimated. This analysis showed that with the progression of grazing the amount of biomass decreased and the degree of spatial heterogeneity in biomass, measured per 0.25m², increased, and due to plant regrowth the trends were reversed. By rearranging the 100 biomass data in order of weight, it was suggested that plots with an extremely large biomass were not grazed by cattle and remained in the pasture. For the same data, variations of biomass along the straight line were divided into two parts based on the moving average: the spatial trend and the residuals which cannot be explained by the trend. In this analysis, 48–75% of the total spatial variation was explained by the trend along the straight line. Analysis using spatial autocorrelation for the actual biomass changes showed that the biomass changes within a range of about 10m on the straight line gave a positive correlation, which indicates a topographical trend in biomass. Spatial autocorrelation for residuals suggested that the spatial changes in biomass along the straight line followed a wave-like or checker-board pattern. Small-scale spatial heterogeneity in plant biomass may be caused by the uneven deposition of excreta by grazing animals, uneven use of the grassland by grazing animals, and uneven dispersal of plant seeds through faeces over the grassland. The possibility that such unevenness might accelerate energy flow in the grassland ecosystem and contribute to grassland sustainability is discussed.     

The Distribution of Grassland Auchenorrhyncha Assemblages (Homoptera: Cercopidae, Cicadellidae, Delphacidae) in Northern England and Scotland

The distribution of Auchenorrhyncha species assemblages on 174 grassland sites in northern England and Scotland was investigated using ordination and classification techniques. Altitude appeared to be the most important environmental variable influencing assemblage distribution but the effects of altitude on soil type and moisture, and on plant composition, either herbaceous or woody, and structure were likely to have been primary influences. The main differences between sites in the eight habitat groups of the classification were products of these soil and plant variables, with the geographical position of sites in the survey area having less of an effect on site classification. A considerable number of nationally and regionally rare and scarce species were recorded. The results indicate that Auchenorrhyncha could be used in site conservation based on invertebrate species assemblages and rare species distribution but that more information is required to assess both habitat diversity and species rarity. More survey work would also be required to identify appropriate site management procedures for the conservation of Auchenorrhyncha within an overall programme for terrestrial invertebrates.     

Spatial and temporal patterns in Arctic mosquito abundance

1. Organisms that undergo a shift in ontogeny and habitat type often change their spatial distribution throughout their life cycle, but how this affects population dynamics remains poorly understood.
2. We examined spatial and temporal patterns in Aedes nigripes abundance, a widespread univoltine Arctic mosquito species (Diptera: Culicidae), hypothesizing that the spatial distribution of adults would be closely tied to aquatic habitat.
3. We tracked adult densities of A. nigripes near Kangerlussuaq, Greenland using emergence traps, CO₂-baited traps, and sweep-nets.
4. In back-to-back years of sampling (2017 and 2018) we found two-fold variation in overall abundance.
5. Adults were spatially patchy when first emerging from aquatic habitats but within a week, mean capture rates for host-seeking adult females were similar across locations, even in places far from larval habitat.
6. Daily variation in mosquito captures was primarily explained by weather, with virtually no mosquito activity when temperatures averaged less than 8°C or wind speeds exceeded 6 m/s. Gravid females (3% of resting adults) were spatially patchy on the landscape, but not always in the same places where most adults emerged.
7. The spatial distribution of adults is quickly uncoupled from the spatial distribution of larvae because A. nigripes females may disperse far from their natal habitats in search of a blood-meal and high-quality oviposition habitat.

8. This research highlights the value of studying ecological processes that act at disparate life stages for understanding the population biology of organisms with complex life cycles.     

Spatial and temporal determinants of genetic structure in Gentianella bohemica

The biennial plant Gentianella bohemica is a subendemic of the Bohemian Massif, where it occurs in seminatural grasslands. It has become rare in recent decades as a result of profound changes in land use. Using amplified fragment length polymorphisms (AFLP) fingerprint data, we investigated the genetic structure within and among populations of G. bohemica in Bavaria, the Czech Republic, and the Austrian border region. The aim of our study was (1) to analyze the genetic structure among populations and to discuss these findings in the context of present and historical patterns of connectivity and isolation of populations, (2) to analyze genetic structure among consecutive generations (cohorts of two consecutive years), and (3) to investigate relationships between intrapopulational diversity and effective population size (N(e)) as well as plant traits. (1) The German populations were strongly isolated from each other (pairwise F(ST)= 0.29-0.60) and from all other populations (F(ST)= 0.24-0.49). We found a pattern of near panmixis among the latter (F(ST)= 0.15-0.35) with geographical distance explaining only 8% of the genetic variance. These results were congruent with a principal coordinate analysis (PCoA) and analysis using STRUCTURE to identify genetically coherent groups. These findings are in line with the strong physical barrier and historical constraints, resulting in separation of the German populations from the others. (2) We found pronounced genetic differences between consecutive cohorts of the German populations (pairwise F(ST)= 0.23 and 0.31), which can be explained by local population history (land use, disturbance). (3) Genetic diversity within populations (Shannon index, H(Sh)) was significantly correlated with N(e) (R(S)= 0.733) and reflected a loss of diversity due to several demographic bottlenecks. Overall, we found that the genetic structure in G. bohemica is strongly influenced by historical periods of high connectivity and isolation as well as by marked demographic fluctuations in declining populations.     

Type and spatial structure of distribution data and the perceived determinants of geographical gradients in ecology: the species richness of African birds

Aim Studies exploring the determinants of geographical gradients in the occurrence of species or their traits obtain data by: (1) overlaying species range maps; (2) mapping survey‐based species counts; or (3) superimposing models of individual species’ distributions. These data types have different spatial characteristics. We investigated whether these differences influence conclusions regarding postulated determinants of species richness patterns. Location Our study examined terrestrial bird diversity patterns in 13 nations of southern and eastern Africa, spanning temperate to tropical climates. Methods Four species richness maps were compiled based on range maps, field‐derived bird atlas data, logistic and autologistic distribution models. Ordinary and spatial regression models served to examine how well each of five hypotheses predicted patterns in each map. These hypotheses propose productivity, temperature, the heat–water balance, habitat heterogeneity and climatic stability as the predominant determinants of species richness. Results The four richness maps portrayed broadly similar geographical patterns but, due to the nature of underlying data types, exhibited marked differences in spatial autocorrelation structure. These differences in spatial structure emerged as important in determining which hypothesis appeared most capable of explaining each map's patterns. This was true even when regressions accounted for spurious effects of spatial autocorrelation. Each richness map, therefore, identified a different hypothesis as the most likely cause of broad‐scale gradients in species diversity. Main conclusions Because the ‘true’ spatial structure of species richness patterns remains elusive, firm conclusions regarding their underlying environmental drivers remain difficult. More broadly, our findings suggest that care should be taken to interpret putative determinants of large‐scale ecological gradients in light of the type and spatial characteristics of the underlying data. Indeed, closer scrutiny of these underlying data — here the distributions of individual species — and their environmental associations may offer important insights into the ultimate causes of observed broad‐scale patterns.     

Problems in studying populations of the golden sun-moth, Synemon plana (Lepidoptera: Castniidae), in south eastern Australia

Surveys of the threatened golden sun-moth, Synemon plana (Walker), on an extensive grassland habitat in Victoria demonstrate some of the challenges for evaluating its population sizes and distributions, and developing its flagship values for ranking grassland sites for priority conservation significance. A more effective sampling protocol is suggested, which takes into account the unusual biological features of this species.     

黄土高原丘陵沟壑小流域土壤水分垂直分布变异特征及影响因子

以地统计学的半变异函数为分析工具,分析了黄土高原丘陵沟壑区小流域土壤水分在垂直方向的空间变异特征以及土地利用类型和地形等因子对其的影响.结果表明:1)球状模型可以很好地拟合土壤水分在垂直方向的半变异函数曲线,其存在强烈或中等程度的空间自相关,变程范围从2～5 m不等;2)果园对土壤水分含量的影响主要表现在1～2 m深度,5月份含量最高,且分布均匀,8月份由于气温和叶面蒸腾作用,水分含量最低.坡耕地和梯田的水分含量都较高,垂直变化不明显,梯田的土壤水分含量最低月份是9月,比坡耕地晚1个月,这是因为所种作物的主要生长季节为9月份,这期间消耗水分较多而造成的.林地由于根系发达,对土壤水分垂直方向的变化的影响比较大,变化为先增大、再减小、最后再增大且分布趋于平缓.灌木林的土壤水分含量整体较低,主要变化深度范围集中在0～2 m;草地的土壤水分含量较高,垂直变化的深度范围集中在1 m以内;3)坡度、坡向地形因子和土壤水分的垂直方向变异特征没有呈现明显的相关性.     

河南省土壤有机碳分布空间自相关分析

运用空间自相关方法,对河南省1958年(第1次土壤普查)和1985年(第2次土壤普查)两个时间段土壤有机碳储量分布状况进行了研究.结果表明:空间自相关指标能够比较清楚地描述河南省2次土壤普查土壤有机碳储量的地理空间变化.1958年和1985年河南省土壤有机碳总储量分别约为54·93×108t和69·65×108t,年均增长率达1%.土壤有机碳密度时空分布总趋势为豫东南角及豫西高于豫东,豫北及豫中介于两者之间;豫东南角单位面积土壤有机碳储量损失较快,最快损失速率达到年均1·57%;豫东单位面积土壤有机碳储量增加较快,最大增长速率达到年均5·27%.河南省单位面积土壤有机碳储量的时空变化与土壤初始含碳量密切相关,土壤初始含碳量越高,有机碳损失越快.     

空间分子生态学——分子生态学与空间生态学相结合的新领域

分子标记、基因流、种群空间动态是当前生命科学研究中的热点领域。RFLPs、RAPDs、微卫星等新的分子标记的不断涌现,促进了这些领域的飞速发展。对种群空间动态研究中的等级岛屿模型、距离隔离模型、脚踏石模型、集合种群模型等方面许多令人瞩目的进展做了介绍。同时还介绍了遗传距离、基因流及其测度、基因突变模型、3S技术、空间精确性种群模型和基因频率的空间自相关等热点领域。最后,就空间分子生态学存在的问题与前景进行了讨论,指出了空间分子生态学可能的发展方向。     

Spatial and temporal variation of ecosystem properties at macroscales

Although spatial and temporal variation in ecological properties has been well‐studied, crucial knowledge gaps remain for studies conducted at macroscales and for ecosystem properties related to material and energy. We test four propositions of spatial and temporal variation in ecosystem properties within a macroscale (1000 km's) extent. We fit Bayesian hierarchical models to thousands of observations from over two decades to quantify four components of variation – spatial (local and regional) and temporal (local and coherent); and to model their drivers. We found strong support for three propositions: (1) spatial variation at local and regional scales are large and roughly equal, (2) annual temporal variation is mostly local rather than coherent, and, (3) spatial variation exceeds temporal variation. Our findings imply that predicting ecosystem responses to environmental changes at macroscales requires consideration of the dominant spatial signals at both local and regional scales that may overwhelm temporal signals.     

围栏放牧下土壤-植被碳密度空间分布格局

对围封13年且放牧的冷季高寒矮嵩草草甸,进行了从围栏入口到内部不同距离植被和土壤碳密度状况的调查.结果表明:1)入口到50 m植被现存碳密度平均为1298.0gC·m-2,60～180m有所下降(平均为997.3 g C·m-2),200～300 m反而升高(平均为1285.5 g C·m-2).当年净初级生产碳密度分布趋势与其相同,0～50 m、60 ～180 m和200～300 m平均分别为742.5、571.0和745.7 g C·m-2.这种分布趋势与放牧过程中绵羊觅食频度和强度有关.一般在中央地带放牧强度大,绵羊觅食时间长,边缘地带受围栏效应或围栏外环境因素影响,放牧强度相对较弱,一定程度上对植被生长发育起到了保护作用,使边缘地带植被碳密度得到提高.2)从围栏入口到草场内部土壤碳密度变化趋势表现复杂,入口到100 m增加,100～170 m减小,然后略有升高.土壤碳密度最高值出现在95 m处(15.42 g C·m-2),最低值出现在170 m处(14.12 gC· m-2).目前尚不清楚为何出现这种格局,但至少认为,土壤有机质的动态转化过程受多种因素影响,与植被碳密度相比具有一定的迟滞效应.具体如何影响有机质的动态转化及其迟滞效应,有待进一步研究.     

Habitat constraints limit the distribution and population density of redwing francolin, Francolinus levaillantii, in the highland grasslands of Mpumalanga province, South Africa

We investigated a variety of habitat characteristics along a land‐use gradient in an attempt to determine which factors may have influenced the population decline of redwing francolin, Francolinus levaillantii, in commercial pasture farms in the highland grasslands of Mpumalanga province, South Africa. Within three microhabitats (wetlands, rocky outcrops and grassland), number and diversity of food plants, height of the sward and percentage cover were significantly lower in habitat exposed to commercial grazing with sheep. Increased cover and height of the sward were positively correlated with higher diversity and availability of francolin food plants. Crop analyses revealed a lower intake in the number of food plant species, but higher incidence of invertebrates, ingested by birds collected in heavily grazed and frequently burned grasslands. Intestinal caecae were significantly (P < 0.001) longer in birds collected from grazed/burned grasslands – possibly associated with a low quality, more fibrous diet. Both the quantity and quality of habitat in terms of food abundance, diversity and cover are important factors influencing the distribution of redwing francolin in these grasslands.     

鄱阳湖浮游甲壳动物群落结构特征

鄱阳湖是中国第一大淡水湖,具有"丰水为湖,枯水为河"的独特特点。为探讨鄱阳湖浮游甲壳动物群落结构及其时空分布的特征,于2009年全年采集其不同季节、不同水位期的浮游甲壳动物样品进行定量分析。结果显示,鄱阳湖浮游甲壳动物群落结构总体与河流浮游甲壳群落具有相似性。无节幼体、象鼻溞、剑水蚤等河流优势类群在鄱阳湖浮游甲壳动物中占优势;而哲水蚤和溞属仅在低水位季节占优势,枝角类丰度仅在高温、高水位、流速缓的季节高过桡足类。丰水期浮游甲壳动物平均丰度和生物量远远高于枯水期,可达枯水期的50倍,差异极其显著(P0.01)。温度和水位变化引起的环境因子改变是导致鄱阳湖浮游甲壳动物发生季节演替的主要原因;而营养盐对浮游甲壳动物的影响并不显著。空间上浮游甲壳动物群落构成明显不同,年均丰度最高和最低的点均出现在河口地区。因此:对于换水周期短,水交换速率快的水体,应该充分考虑水文条件对生物的影响。     

Spatial and temporal variation of fish assemblage in two intermittent streams in north‐western Zimbabwe

This study examined the spatial and temporal variation in fish assemblage composition within two intermittent streams in north‐western Zimbabwe. Eight sites were sampled during three different periods of flow. Twenty‐five species in eight families, dominated by cichlids and cyprinids, were collected. Redundancy analysis (RDA) was used to explore the relationship between species and their environmental correlates. According to variation partition, 68.1% of assemblage variation was explained by both habitat and temporal variables. Most species were associated with large pools, whereas small species were associated with habitats that had gravel and boulders. The temporal aspect suggested a pattern associated with high catch per unit effort (CPUE) for the mormyrids, Clarias gariepinus and Labeo altivelis, during the early rain period. By comparison, the late rain period was associated with high CPUE for Labeo cylindricus, Labeobarbus marequensis, Chiloglanis neumanni and Oreochromis mortimeri, whereas the rest of the species had high CPUE during both the late rain and dry periods. The assemblage composition was more diverse during the late rain period. Refuge availability during the dry period appeared to be essential for the assemblage of the intermittent streams. Protection of these temporal habitats is therefore important in conserving fish assemblages within intermittent streams of the Lake Kariba area.     

水杉孑遗居群AFLP遗传变异的空间分布

本研究采用空间自相关分析方法对水杉 (Metasequoiaglyptostroboides)孑遗居群AFLP遗传变异的空间结构进行了研究 ,以探讨水杉孑遗居群遗传变异的分布特征及其形成机制。根据 6对AFLP选择性引物扩增的 46个多态性位点 ,选择了其表型频率在 2 5 %～ 75 %的 2 7个AFLP标记 ,运用等样本频率方法和等地理距离间隔方法分别对 3 9株和 3 7株原生母树进行了空间自相关系数Moran’sI值计算。结果表明 :水杉孑遗居群缺乏空间结构 ,绝大多数AFLP位点变异为随机分布的空间模式 ,但也有少数位点存在显著性随机相关 ,在 4～ 8km地理距离间隔显示负相关 ,说明该间隔可能是水杉孑遗居群的部分基因交流的有效屏障。水杉原生母树分布存在 12～ 2 8km的明显距离间隔空挡 ,说明人类从迁入该区域起就影响着水杉孑遗居群的原始生境 ,导致其生境片断化、景观破碎 ,进而形成岛屿状分布格局 ,并引起了水杉残留居群的随机遗传漂变。根据本研究结果 ,结合水杉孑遗居群较低的遗传多样性 ,分析探讨了水杉孑遗居群濒危的机理 ,并提出了相应的保育策略 ,为水杉的有效保育提供了科学依据