Roger L. H. Dennis

Can hay harvesting detrimentally affect adult butterfly abundance

Butterfly transects were carried out in the meadows and tracks of a 1.5xa0×xa01.6xa0km study area in the Cantabrian section of the Picos de Europa, Spain to examine the impact of hay harvesting on adult butterfly numbers. Overall butterfly numbers significantly decreased between transect counts taken before and after harvesting in cut fields; no such decline was evident in fields without active management (harvesting/grazing) over the same period. Family-level analysis showed hay harvesting to significantly impact on the Satyridae but not other groups. In fields not undergoing active management no Family-level declines were evident, but the Lycaenidae significantly increased in abundance over the same period. Butterfly abundance on tracks surrounding the meadows significantly decreased during the hay harvest period, but this was not reflected in significant decreases in any particular Family group. The results are discussed in relation to the time of harvesting during the day, and socioeconomic changes in extensive pastoral landscapes.

Island size is not the only consideration. Ranking priorities for the conservation of butterflies on Italian offshore islands

Ecological and historical factors virtually create a unique faunal assemblage on each island. From this perspective every island deserves protection. However, economic limitations usually restrict conservation efforts to particularly important areas. As part of the SLOSS issue (the relative importance of single large or several small areas), there is the long debated question of whether it is better to protect few large areas (islands) or several small areas (islands). Here, we assess the butterfly faunas of the Italian offshore islands, using several biodiversity measures, in order to highlight priorities for conserving butterfly richness, rarity and endemicity. First, the nested pattern of butterfly fauna was investigated to determine the relative importance of large and small islands. Then, residuals were assessed for the species-area relationship and for multiple regressions of richness, rarity and endemicity against geographic variables. Subsequently, two other indices were calculated: Biodiversity Conservation Concern and an index scoring islands in the order that maximizes the cumulative percentage of total, endemic, and rare species. The results clearly indicate that although greatest concern is for the island having the largest butterfly fauna in the sample (Elba), the importance of several small islands should not be ignored. This is primarily due to the substantial impact of source areas and consequently the occurrence of several rare and endemic species occurring on small islands as well as on large islands.

Butterflies of European islands: the implications of the geography and ecology of rarity and endemicity for conservation

Depending on their faunal content islands can function as important ‘vehicles’ for conservation. In this study, we examine data on 440 butterfly species over 564 European islands in 10 island groups. To determine the status of the butterfly fauna, we have adopted two approaches, island-focused and species-focused, examined using principal components analysis and regression modelling. In the former, we relate species richness, rarity and endemicity to island geography (area, elevation, isolation and location in latitude and longitude); in the latter, species occurrence on islands is examined in relation to distribution, range, range boundaries, and altitudinal limits on the continent as well as species’ ecology (number of host plants) and morphology (wing expanse). Species on islands are also assessed for their status on the continental mainland, their distributional dynamics (extinctions, distribution changes) and conservation status (Red Data Book, European Habitat Directive, Species of European Conservation Concern and Bern Convention listing. Unexpectedly, we find that a large fraction of the European butterfly species is found on the islands (63.4%; 59% on small islands) comprising some 6.2% of the land area of Europe. Although species occurring on the islands tend, on the whole, to have lower conservation status and are not declining over Europe, 45 species are endemics restricted to the islands. Species richness shows only a weak locational pattern and is related as expected to isolation from the continental source and island area; but, both rarity and endemicity have distinctive geographical bias to southern Europe, on islands now under increasing pressure from climate change and increasingly intensive human exploitation. The vulnerability of species on islands is emphasised in the relationship of island occurrence (% occurrence and presence/absence of species on any island) with continental distributions. A large proportion of the variation (84%) is accounted by continental distribution, the southern range limit and lower altitudinal limit. Most species (69%) occur on very few islands (<5%). In view of ongoing species dynamics on islands, migrations and extinctions of species, island repositories of species depend in large part on conservation of butterflies at continental sources. The unique faunas and rare species on islands also depend on appropriate concern being given to the island faunas. Conservation of European islands is thus a two-way process, sustaining sources and conserving island refuges. Residuals from the regressions (islands with more or fewer species, rare and endemic species; species occurring more or less frequently than expected on islands) provide warning signals of regions and islands deserving immediate attention.

Land-use, environment, and their impact on butterfly populations in a mountainous pastoral landscape: individual species distribution and abundance

Butterflies were studied, at the species level, in 47 mountain meadows in a 1.5xa0×xa01.6xa0km study area in the Picos de Europa National Park, Spain. Butterfly transects were carried out on nine occasions in June and July 2004 and the summed data used in binary logistic and stepwise multiple regression analyses using 28 biotic and abiotic parameters. Models were created for 37 species in total: 24 using logistic regression and 24 with multiple regression; models from both approaches were obtained for 11 species. Abiotic factors dominated many analyses with factors such as proximity to water, aspect and altitude being prominent. Abiotic factors may reflect acceptable minimum conditions for presence of a species and interact with biotic factors to determine habitat quality. Classification of the meadows as either under hay or summer grazing management, or ‘winter grazing or abandoned’ was not particularly revealing probably due to inherent variability in management intensity within meadows and degree of abandonment. Features that reflected management influences, lack of management, disturbance, and sward condition featured in many analyses. Whilst many meadows are still actively managed, features that can be related to abandonment are evident for many species. The early stages of relaxation of management intensity can be positive for butterflies, but if management is not restored losses are likely as succession proceeds. The implications of this are briefly discussed.

Land-use, environment, and their impact on butterfly populations in a mountainous pastoral landscape: species richness and family-level abundance

Extensive grasslands are considered to be of high biodiversity value, but are under threat from intensification and abandonment. We studied butterfly species richness and abundance in 47 hay and grazing meadows in the Picos de Europa, northern Spain in 2004. Nine transects were walked around the perimeter of the meadows from the 1 June to 28 July with butterflies recorded to species or species-group. Land-use, abiotic, and sward variables were also recorded. Change in meadow extent was estimated by comparing a digital map of open meadows with a cadastral map with 1950s provenance. We found: A decrease in open area, mostly attributable to reduction in grazing meadows. 75 or more butterfly species with species richness principally, and positively, influenced by altitude and presence of scrub in the body of the meadow. Hay meadow management was a positive influence on richness of satyrids. When all butterflies were considered together, the only significant factor influencing abundance was Plantago lanceolata (−ve). For sub-groups of the butterfly community there was no consistent pattern, although P. lanceolata was identified as a (−ve) factor in relation to hesperiid, nymphalid, satyrid, and Viola-feeding fritillary groups. Several regression models included components that could be linked to abiotic influences (water, aspect, altitude) but many were indicative of abandonment or relaxation of management intensity (scrub, Pteridium aquilinum, Asphodelus albus), sward components, fragmentation (distance to nearest meadow, number of meadows within 100xa0m), and land use (hay management, summer grazing). The results are discussed in relation to changing socio-economics, including the potential impact of tourism, and the need for financial instruments to support extensive farming.

Skipper impoverishment on large West Mediterranean islands (Lepidoptera Hesperioidea): deterministic, historical and stochastic factors.

Biogeographical analyses are applied to skipper (Hesperioidea) presence/absence data from the Western Mediterranean mainland and the three largest islands (Sardinia, Corsica and Sicily) in order to identify potential conservation issues. The analyses performed on species, both collectively and individually, indicate that regional species richness and occurrence in the Mediterranean zone are largely predicted by latitude and area but that islands have impoverished faunas. Several species, predicted to be present on these islands from logistic regression of their continental distributions, are actually absent. The number of species predicted to be present from logistic regression analyses for each island, closely matched the number of species predicted to occur in regional-focused multiple regression analysis. This suggests that missing species have been identified. When compared with species that occur in Sicily and Corsica, the missing species are shown to differ for ecological traits, mainly those linked to altitudinal tolerance. No ecological distinctions were disclosed for Sardinian skippers suggesting a mainly stochastic colonisation. These results, and those from an analogous study carried out on Papilionoidea, point to Hesperioidea having (i) overall more impoverished faunas on islands and (ii) being subject to stochastic or historical colonisation events more than Papilionoidea. Species not predicted to occur on islands based on their mainland distributions and ecological traits, are foci for conservation attention. However, as many species becoming extinct on the islands may be irreplaceable, all species, in particular the Sardinian ones, deserve to be conserved.

Elevation and habitats: the potential of sites at different altitudes to provide refuges for phytophagous insects during climatic fluctuations

Uplands are expected to provide refuges for species subject to lowland habitat loss and projected climate changes. Here, we argue that upland populations also provide refuges when lowland sites are subject to climatic fluctuations and extreme events and that species with populations dispersed over adjoining uplands and lowlands spread their risk of extinction. A proviso is that development is sufficiently lagged with altitude but that development rates are compatible. Emergence patterns and development of the butterfly Anthocharis cardamines and its larval host plant Cardamine pratensis show these characteristics, and coupled with the butterfly’s capacity to migrate between isolated populations present a case where upland and lowland populations can act as sources when one or the other area is adversely affected by extreme events.

The western jewel butterfly (Hypochrysops halyaetus: Lycaenidae) II: factors affecting oviposition within native Banksia bushland in an urban setting

Oviposition by western jewel butterflies (Hypochrysops halyaetus Hewitson) was studied in the urban Koondoola regional bushland reserve, Western Australia in 1999. Observations were made in a small (70xa0×xa0120xa0m) localised breeding area the ‘microdistribution study area’, and in 14 paired 20xa0×xa020xa0m quadrats randomly placed along established tracks in the interior of the northern half of the reserve. The principal host plant was Jacksoniasternbergiana with the secondary host being Daviesiadivaricata. More Jacksonia were used for oviposition and attended by ants (40 and 71%, respectively) in the microdistribution study than plants in the ‘quadrat’ study (8 and 25%, respectively). Jacksonia stems with basal diameters below 5xa0mm were less likely to have eggs. PCA showed Jacksonia to be associated with disturbed conditions with a high proportion of bare ground whereas Daviesia was associated with more mature vegetation. Jacksonia density was principally correlated with the proportion of bare ground and time since the last fire. Host ant (Crematogasterperthensis) presence and proportion of bare ground were the most important factors influencing oviposition. The presence of ants was closely associated with bare ground conditions and the presence of coccids. Conservation management for floristic diversity and maturity of vegetation in reserves is likely to be a widespread phenomenon, and may negatively affect the persistence of species requiring ephemeral patches of early successional vegetation. For H. halyaetus, a species dependent on disturbed/ephemeral habitat conditions, this conflict may threaten its survival, especially in small reserves, and as a result its conservation status may be underestimated. Management options are discussed.

Butterflies on a Dragon’s Head; Butterflies in a Dragon’s Head1

When Matt and Lee asked me to contribute to this book, I was, at first, bemused by the invitation. Glancing down the familiar list of authors, I was immediately struck by the fact that I was the only lifelong amateur and, very likely, the only one who had missed out completely on school biology (it wasn’t taught then in our arcane institution on the isolated Welsh borderlands). I hadn’t collected butterflies as a hobby, and my PhD was not in butterfly science but on a rather limited aspect (dermatoglyphics) of those distinctly destructive critters: humans. Even now, my entomology lab experience is sparse; no butterfly biology students can claim I ruined their careers, and nose-to-ground fieldwork was abruptly terminated early on in my mid-thirties: any lepidopterist will tell you that is a real killer. I could boast a distinction—perhaps an appalling one for an entomologist—that my butterfly books have the least possible number of plates of set butterflies in them. In my defence, I would retort that I like my animals alive! Anyway, along with the other contributors, and armed with some suitably inspiring homework from Art Shapiro (William Leach’s Butterfly People), I offer some personal recollections before they deliquesce into larval soup.

Tim R New: Butterfly conservation in South-Eastern Australia: progress and prospects

Conserving a region’s plants and animals would be made much easier if there was a simple way of accounting conservation load, for instance by applying an algorithm based on area, diversity and number of humans, or if there was a common indicator taxon that could be applied broadcast as an effective guide to policy. The fact is, no simple formula exists. Each region has unique problems and there is always something new to learn from work in different parts of the world. This observation is amply supported by a compact but intricately woven and exemplary text on East Bassian province butterflies by Professor New. Although the UK and some other parts of Western Europe have the most advanced machinery for conserving butterflies, in no single work has there been such a knowledgeable and intelligent understanding and review of the processes in conserving an insect fauna from identifying the problems, through the ‘political’ minefields, to the ‘groundwork’ for ensuring population persistence and averting taxon and community extinction. To put details on this region (Victoria, Tasmania and much of New South Wales) into context, it contains 216 of Australia’s 427 species (323 of 654 significant taxonomic units), 64 of which are endemic to the region on approximately 10% of the continent’s area containing Australia’s largest cities and over half of Australia’s rapidly growing population of 22.6 million. The book is divided into three parts. The first, ‘Setting the scene’, zooms in from a continental review to this highly pressured zone with its unique butterfly elements. In Chap. 1, background is provided on Australia’s butterflies, their diversity, biogeography, and conservation status, with sensitive insights into the prickly issue of collecting. South East Australian environments are covered in Chap. 2, including threats to butterflies, declines in status, and an outline of key pressures including environmental change and urbanization. These two chapters place the immense scale of problems into focus—the task seems overwhelming; the land, sensitive to environmental factors (drought, flood, fire) and to changes, has been heavily exploited by a vigorous human population, even if small in numbers by European standards. Despite the unique fauna, there is no fine-scale mapping or detailed ecological knowledge to fall back on, nor an army of conservation volunteers to do the physical work or do recording, as in the UK. In fact, there are very few professional entomologists and nothing to match the UK’s ‘Butterfly Conservation’ which has the luxury of selection from a highly qualified professional staff supported by membership, public and private funding (a calculated £6.3 m per annum voluntary input). All these problems exist, and yet there is much more (in every sense) to monitor in SE Australia and for which to cater. Chapter 3 follows with a fascinating insight into the legal issues affecting butterfly conservation. After reading that section, it seemed that a suitable quotation for a chapter leader should perhaps be: ‘Anyone with a delicate constitution should look away now!’ for as expertly demonstrated, small errors in ‘law’ and overly muscular approaches to the fraction of the public knowledgeable about butterflies can make for serious consequences in conservation. The chapter explores the history of legislating for conservation and the difficulties in integrating Commonwealth, State/ Territory and more local protection laws. A crucial section outlines the ‘Butterfly Action Plan’ for some 220 taxa compiled by Professor New and a colleague Dr Don Sands R. L. H. Dennis (&) Institute for Environment, Sustainability and Regeneration, Staffordshire University, Mellor Building, College Road, Stoke-on-Trent ST4 2DE, UK e-mail: rlhdennis@aol.com