Marginality: scale determined processes and the conservation of the British butterfly fauna

Marginality describes the impact that environmental and landscape factors have in decreasing the probability of population survival and persistence. It may be imposed by extreme conditions or resource scarcity. Typically, it affects populations at the range edge but can also affect populations within the core of ranges, and produces a number of symptoms: characteristically demographic, but also morphological, physiological, biochemical and genetic. In this paper, the causes and effects of marginality on British butterflies are compared in edge and centre of range populations. Issues of temporal and spatial scales are examined, as is the relevance of marginality to the conservation of single and multiple species populations. The recognition of marginality questions the appropriateness of many so-called spatially realistic models of populations and highlights areas of research which have hitherto been ignored. Projected changes in land use and climate have implications for marginality in core and peripheral populations; in view of this, current scales of mapping are found to be unsuitable for monitoring fragmentation and the increasing marginalization of butterfly species in the British landscape.     

Wisconsin desmids. I. Aufwuchs and plankton communities of selected acid bogs,alkaline bogs,and closed bogs

Data are presented for 28 acid bogs, five alkaline bogs, and 12 closed bogs in Wisconsin with respect to the summer composition of the aufwuchs and plankton ccommunities, the relative importance of desmids in these communities, and the structure of aufwuchs communities associated with different macrophyte hosts. Generic diversity of desmids is highest in acid bogs and lowest in alkaline bogs and generally is greater in the aufwuchs community than in the plankton community at a given site. Whenever it was present, the greatest diversity occurred in association with the macrophyte host Utricularia. Among lakes of a given type, relationships between the occurrence of desmid genera and parameters of the chemical environment were not apparent for either the aufwuchs or plankton communities. Similarly, no clear-cut distinctions occur in the desmid communities of the three lake types in terms of population densities and percentage contribution to the total population, but acid bogs tend to have a somewhat more prominent flora quantitatively. Statistically significant differences in desmid population densities from one host to another within a given lake did occur in lakes of all three types, and this suggests that the nature of the substrate can definitely influence community size and composition. Data for other algal groups are similarly treated, and brief comparisons of the mat and open water communities of alkaline bogs are included.     

The Californian urban butterfly fauna is dependent on alien plants

Abstract. Using the unusually well-documented butterfly fauna of Davis, Yolo County, California, it is shown that the mainly native species commonly observed in gardens breed mostly or entirely on alien plants, especially naturalized weeds. Over 40% of the fauna has no known native hosts in the urban–suburban environment. Were certain alien weeds to be eradicated or their abundance greatly reduced, the urban-suburban butterfly fauna would disappear. This might be regarded as an unfortunate, and perhaps intolerable, side-effect of such programs.     

Resource use of specialist butterflies in agricultural landscapes: conservation lessons from the butterfly Phengaris (Maculinea) nausithous

Most of the European grassland butterfly species are dependent on species rich grasslands shaped by low intensity farming. Conservation of these specialist species in agricultural landscapes relies on knowledge of their essential resources and the spatial distribution of these resources. In The Netherlands, the dusky large blue Phengaris (Maculinea) nausithous butterflies were extinct until their reintroduction in 1990. In addition, a spontaneous recolonization of road verges in an agricultural landscape occurred in 2001 in the southern part of The Netherlands. We analyzed the use of the essential resources, both host plants and host ants, of the latter population during the summers of 2003 and 2005. First we tested whether the distribution of the butterflies during several years could be explained by both the presence of host plants as well as host ants, as we expected that the resource that limits the distribution of this species can differ between locations and over time. We found that oviposition site selection was related to the most abundant resource. While in 2003, site selection was best explained by the presence of the host ant Myrmica scabrinodis, in 2005 it was more strongly related to flowerhead availability of the host plant. We secondly compared the net displacement of individuals between the road verge population and the reintroduced population in the Moerputten meadows, since we expected that movement of individuals depends on the structure of their habitat. On the road verges, butterflies moved significantly shorter distances than on meadows, which limits the butterflies in finding their essential resources. Finally we analyzed the availability of the two essential resources in the surroundings of the road verge population. Given the short net displacement distances and the adverse landscape features for long-distance dispersal, this landscape analysis suggests that the Phengaris population at the Posterholt site is trapped on the recently recolonized road verges. These results highlight the importance of assessing the availability of essential resources across different years and locations relative to the movement of the butterflies, and the necessity to careful manage these resources for the conservation of specialist species in agricultural landscapes, such as this butterfly species.     

High and dry or sunk and dunked: lessons for tallgrass prairies from quaking bogs

Northern Wisconsin bogs provide a natural experiment on butterfly population occurrence in a naturally highly fragmented vegetation type, which may provide insight on conserving butterflies in anthropogenically fragmented and degraded landscapes. We surveyed butterflies in bogs (about as unaffected by humans as possible, but naturally occurring over <1% of northern Wisconsin) primarily during 2002?C2009, with additional observations from 1986 to 2001. Different bog types had different bog-specialist butterfly faunas, but bog butterfly abundance also differed in similar vegetations among subregions. Some small isolated bogs held very high densities of specialist butterflies. Summer but not spring specialists frequented adjacent lowland roadsides and utilized a variety of non-native as well as native nectar sources. Paleo-entomology indicates that insects don??t evolve out of trouble; instead they move out of trouble. Given the low dispersal apparent today for species restricted to bogs, ??move?? might be better understood as ??hunkering?? within their vegetation as it expands and shrinks and moves around the landscape. Although bogs appeared to have more intact specialist butterfly faunas than tallgrass prairies (99.9% destroyed by human activities), bog butterflies do not live in average sites even in a relatively natural landscape. Just as bog butterflies are ??sunk and dunked?? in isolation, specialist butterflies elsewhere may have been left ??high and dry?? naturally, or are now due to human activities. Numerous studies have demonstrated that presence and abundance of specialist butterflies increase with increasing size and connectedness of habitat patches. But with long-term consistent vegetation, populations with high abundances in small isolated sites and with low numbers thinly occurring in large sites can be secure, as shown by bog butterflies.     

重庆市珍稀蝶类及保护对策

重庆市有 14种珍稀蝶类 ,主要分布在东北部、南部和东南部的 17个区 (市 )县 ,其中以江津、万盛、巫山、巫溪、城口、南川、彭水等 7个区 (市 )县最为重要。重庆市珍稀蝶类的保护对策是 ,加强法规制订和宣传 ,对濒危保护蝶类生物特性、生态学和行为学等方面进行专题研究 ,加强蝶类生栖地的保护和恢复 ,贯彻护·养·猎并举、以养蝶为主持续利用方针。     

The use of habitat mosaics by terrestrial vertebrate fauna: implications for conservation and management

Many species of vertebrates require multiple habitats to obtain different resources at different stages of their life-cycles. Use of habitat mosaics takes place on a variety of spatial and temporal scales, from a daily requirement for adjacent habitats to seasonal use of geographically separated environments. Mosaics of habitats are also required in some species to allow ontogenetic habitat shifts, while in others each sex may have specific requirements that are met by different habitats. The extent and nature of animal movements are key (but generally poorly known) factors affecting the vulnerability of species to landscape change. The requirement by many species for multiple habitats suggests that their conservation will be most effective in a mosaic environment and that protection of certain high profile habitats alone, such as rainforest, will be insufficient to achieve conservation goals. Management regimes that result in homogenization of habitats should be avoided. Priority should be given to research that identifies the extent to which species can locate habitat mosaics, at different spatial scales and arrangements, in modified environments.     

Patterns of butterfly distribution in the Andaman islands: implications for conservation

Twenty-five islands of different sizes were rapidly surveyed in the Andaman islands for patterns of butterfly distribution and abundance. The surveys were conducted in the dry seasons of 1992 in the South Andaman islands, 1994 in the North Andaman islands and on both these years on the Little Andaman Island. Different habitat types were identified on each island and butterflies were sampled by the line transect method in each habitat type. Sixty-five species of butterflies were recorded from six families. Fifty-one species were less common and contributed to 25 % of the total count. Six species were very common. The overall distribution patterns of the species were nested. This suggests that small islands share their species with the larger islands but not vice versa. Many uncommon species were found exclusively on large islands. The presence of evergreen forest on islands significantly influenced the species encountered. Small and medium sized islands with evergreen forests had significantly more species than those without evergreen forests. Loss of primary forests due to logging and encroachment will result in the loss of many butterfly species. It is recommended that the large patches of primary evergreen forests be protected on a priority basis on large islands.     

Tasmanian devil facial tumour disease: lessons for conservation biology

Tasmanian devil facial tumour disease is an infectious cancer that threatens the largest surviving marsupial carnivore with extinction. After emerging in 1996, it has spread across most of the range of the species, leading to a population decline of more than 60%. This bizarre disease, in which the cancer cells themselves are the infective agent, illustrates some important general principles about disease and conservation biology, including the threat posed by loss of genetic diversity and the potential of pathogens with frequency-dependent transmission to cause extinction.     

Reading the complex skipper butterfly fauna of one tropical place

Background

An intense, 30-year, ongoing biodiversity inventory of Lepidoptera, together with their food plants and parasitoids, is centered on the rearing of wild-caught caterpillars in the 120,000 terrestrial hectares of dry, rain, and cloud forest of Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. Since 2003, DNA barcoding of all species has aided their identification and discovery. We summarize the process and results for a large set of the species of two speciose subfamilies of ACG skipper butterflies (Hesperiidae) and emphasize the effectiveness of barcoding these species (which are often difficult and time-consuming to identify).

Methodology/Principal Findings

Adults are DNA barcoded by the Biodiversity Institute of Ontario, Guelph, Canada; and they are identified by correlating the resulting COI barcode information with more traditional information such as food plant, facies, genitalia, microlocation within ACG, caterpillar traits, etc. This process has found about 303 morphologically defined species of eudamine and pyrgine Hesperiidae breeding in ACG (about 25% of the ACG butterfly fauna) and another 44 units indicated by distinct barcodes (n = 9,094), which may be additional species and therefore may represent as much as a 13% increase. All but the members of one complex can be identified by their DNA barcodes.

Conclusions/Significance

Addition of DNA barcoding to the methodology greatly improved the inventory, both through faster (hence cheaper) accurate identification of the species that are distinguishable without barcoding, as well as those that require it, and through the revelation of species “hidden” within what have long been viewed as single species. Barcoding increased the recognition of species-level specialization. It would be no more appropriate to ignore barcode data in a species inventory than it would be to ignore adult genitalia variation or caterpillar ecology.     

南岭眼蝶科区系及冰冻灾害前后的调查

南岭是广东的屏障和南北动植物的起源和分化中心,生物资源十分丰富,巳发现50种眼蝶,其中分布在东洋区有44种,占总数的88％;东洋区与古北区共有种5种,占10％;跨区系分布的占2％。今年初的雨雪冰冻灾害使南岭海拨500～1000m森林生态遭受严重破坏,许多野生动物被冻死,眼蝶只发现14种,与常年相比,见到的种群仅为常年的28％,种群密度则不到常年的10％。     

Identifying important areas for butterfly conservation in Italy

The current study combines the use of niche modelling with a site prioritization method to identify important areas for butterfly conservation in Italy. A novel machine learning method (bagging predictors) was used to predict the distribution of 232 species of butterflies across the Italian Peninsula. The results of the models were used to identify high-value sites with a multispecies prioritization method called zonation. In order to identify important areas for species of conservation concern, we incorporated a species weighting scheme to zonation analyses. We also used the results of the zonation analyses to identify a series of management landscapes on the basis of the similarity in species composition among sites. The basic zonation showed that most important areas for butterfly conservation are located in the Alps, the Appennine, the Apulia region and in the island of Sardinia. The inclusion of a species weighting scheme in the zonation analyses revealed the importance of two new areas located in Southern Italy and emphasized the importance of the Alps for species of conservation concern. The landscape identification procedure selected a series of landscapes, which provide protection to a full range of species ranging from the Alps to Mediterranean areas. Our study shows that the areas selected in our analyses should be given high priority in future conservation plans and monitoring schemes.     

Monarch butterfly migration in North America: Controversy and conservation

The monarch butterfly is the most spectacular example of insect migration known. Monarchs are threatened by the destruction of their over-wintering sites in Mexico, California and elsewhere, and many efforts are being made to conserve these sites. However, a controversial recent suggestion, that some monarch populations may not migrate at all, has jeopardized some of these efforts. This article assesses the evidence for and against the new suggestion.     

Obligate groundwater fauna of France: diversity patterns and conservation implications

We examined taxonomic and geographic patterns of the obligate groundwater fauna (i.e. stygobiotic fauna) by assembling in a distributional data base all species occurrences reported from France since 1805. A simulated annealing algorithm was used to identify conservation targets. Until the 60s, biological surveys were restricted to caves but the proportion of sampling sites in unconsolidated sediments increased from 1 to 16% over the last 40 years. A total of 380 species and subspecies in 40 families were collected, 70% of which being restricted to France. As observed in other temperate regions, the stygobiotic fauna was dominated by crustaceans (65% of species) and molluscs (22%). The cumulative number of species did not level off over time, clearly showing that biodiversity was underestimated. Temporal trends in the cumulative number of obligate groundwater and surface water species suggested that groundwater comprised more crustaceans than surface freshwater. Endemism was high although the geographic range size of species increased as distributional data accumulated. Of 380 species, 156 were known from a single 400-km² cell, among which 73% were located in the southern third of France. The distribution map of species richness changed dramatically over time, indicating that the location of richness hotspots was sensitive to sampling effort. Less than 2% of the French landscape was needed to capture 60% of known species. Thus, a large proportion of species could be protected by focusing habitat conservation efforts on a few complementary species-rich aquifers located in distinct regions.     

Key traits in a threatened butterfly and its common sibling: implications for conservation

We ask here which traits predispose one species to extreme rarity and possible extinction while a sympatric sibling is geographically widespread. With background knowledge on the level of habitat specialization of the two species, the population structure and movement of the localized and threatened Orachrysops ariadne were compared to those of the common and highly sympatric O. subravus, using mark-release-recapture. Of a total of 290 marked O. ariadne individuals 42.8% were recaptured, while of 631 O. subravus individuals 49.3% were recaptured. The Jolly-Seber model was used to estimate daily population numbers (N _i ), survival rates (ϕ _i ), recruitment rates (B _i ), proportion of marked animals in the total population (∝_i), and the number of marked animals at risk (M _i ). O. ariadne is a remarkably rare animal, averaging only 10 individuals ha⁻¹ within its small, remaining colonies. Average residence times of male adults were generally similar in both species, being just over 5 days. O. ariadne is a strong and rapid back and forth flier, covering mean recapture distances of 157 m, almost twice that of O. subravus, principally in search of scarce nectar sources. In short, the rarity of O. ariadne is not so much to do with behaviour, survivorship or longevity, but rather with limited availability of the specialized habitat patches for both larvae and adults, and, in particular, the extreme scarcity of the host plant. Evidence suggests that there has been very high selection pressure on the key trait of strong flight as a compensation for going down the apparently highly risky path of extreme microhabitat specialization. Of concern for conservation of this rare species is that these rare habitat patches have become increasingly isolated through transformation of the surrounding landscape. Reduction of the barrier effects of agroforestry through creation of linkages between colonies is recommended, especially as O. ariadne is such a strong flier. Such corridors are indeed now being implemented.     

The Auchenorrhyncha fauna of peat bogs in the Austrian part of the Bohemian Forest (Insecta,Hemiptera)

The first overview on the Auchenorrhyncha fauna of peat bogs of the Austrian Bohemian Forest is presented. Seven oligotrophic peat bog sites were studied in 2011 by suction sampler (“G-Vac”) and 93 Auchenorrhyncha species (with 7465 adult specimens) were recorded. Eleven species (about 18 % of the individuals) are tyrphobiontic or tyrphophilous. The relative species abundance plot is not very steep; the six most abundant species represent 50 % of the individuals. The most common species is Conomelus anceps (17 % of the individuals). Compared to the whole Austrian Auchenorrhyncha fauna, the fauna of peat bogs comprises distinctly more univoltine species and more species hibernating in nymphal stage. Densities of adult Auchenorrhyncha in peat bogs are low in spring (about 10–60 individuals per m²) and high in July, with up to 180 (±50) individuals per m². Disturbed peat bogs have higher species numbers and higher Auchenorrhyncha densities in total, but lower numbers and densities in peat bog specialists.