Showing papers in "Journal of Insect Conservation in 2008"
TL;DR: It is suggested that competition for nest sites rather than flower resources is the major ecological mechanism for displacement of native bees, which may cause local extinction of native bumblebees.
Abstract: The introduced Bombus terrestris has recently been naturalized in Japan and become dominant in some local communities. We investigated potential niche overlaps between introduced and native bumblebees in terms of morphological characteristics, seasonal flight activity, foraging and nesting habitat use, and plant species visited. There were considerable niche overlaps in flower resource use between B. terrestris and B. hypocrita sapporoensis/B. pseudobaicalensis. Bombus terrestris also potentially competes for nest sites with B. hypocrita sapporoensis. During 3-year monitoring, B. pseudobaicalensis showed no noticeable change, but B. hypocrita sapporoensis decreased while B. terrestris increased. Abundant flower resources provided by exotic plants may buffer native bumblebees from competition for food with introduced species. By contrast, the number of nest usurpers found in B. terrestris nests increased between 2003 and 2005, indicating that availability of nest sites was limiting and queens strongly competed for nest sites. Our findings suggest that competition for nest sites rather than flower resources is the major ecological mechanism for displacement of native bees. The large reduction of B. hypocrita sapporoensis queen indicates that B. terrestris may cause local extinction of native bumblebees. Control of established B. terrestris populations and prevention of further range expansion are urgently needed.
167 citations
TL;DR: A rapid extirpation of a strong population of globally threatened butterfly, Colias myrmidone, from the White Carpathians, Czech Republic is described, rendering the species effectively extinct.
Abstract: We describe a rapid extirpation of a strong population of globally threatened butterfly, Colias myrmidone, from the White Carpathians, Czech Republic. The area is renowned for a high plant and insect diversity associated with savannah-like Carpathian meadows, traditionally managed by mowing once a year and subsequent autumn grazing. Although many meadows fell victim to land consolidation schemes in the 1970s and 1980s, over 2000 hectares have been preserved in a dense network of reserves. The reserve management practised since the mid-1990s has consisted of uniform machine mowing of entire areas and this was further accelerated after accession of the Czech Republic to the EU, when agri-environmental schemes (AES) required two cuts per year. This starkly conflicted with the life history of C. myrmidone, because both spring and autumn cuts interfere with larval development. Despite intensive surveys, only five and then two C. myrmidone individuals were seen in the area in 2005 and 2006, respectively, rendering the species effectively extinct. Conservation authorities failed by neglecting early warning signals issued by amateur entomologists, and by ignoring the basic tenets of conservation of insect diversity, such as the need to maintain heterogeneity of resources. Unless AES provide for this crucial aspect of habitat suitability for invertebrates, they may turn from a great hope into a massive failure.
127 citations
TL;DR: The results suggest that the natural variation of dead wood niches must be maintained to efficiently conserve the whole saproxylic beetle fauna of beech forests, even if the initial tree-species composition is maintained, which was the case in this study.
Abstract: Compared to agricultural land and spruce plantations, central European beech-oak forests are often relatively close to natural conditions. However, forest management may alter these conditions. In Steigerwald, southern Germany, a large beech-dominated forest area, three management intensities were applied during the past 30–70 years. Here, we examined the influence of management intensity on saproxylic beetles in >100-year old mature stands at 69 sampling plots in 2004. We sampled beetles using flight-window traps and time standard direct searches. The community structure based on presence/absence data changed remarkably along the gradient from unmanaged to low-intensity to high-intensity management, but these differences were not evident using abundance data from flight interception traps. Saproxylic species richness decreased in intensively managed forests. Elateridae and threatened species richness peaked in unmanaged forests and in forests under low-intensity management. Saproxylic species richness was dependent on certain micro-habitat factors. These factors were (1) the amount of dead wood for Elateridae, overall and threatened saproxylic beetle richness; (2) the amount of flowering plants for Cerambycidae; (3) the richness of wood-inhabiting fungi for Staphylinidae, Melandryidae and overall saproxylic beetle richness; and (4) the frequency of Fomes fomentarius for threatened species. Species richness was better explained by plot factors, such as dead wood or fungi, than by management intensity. These results suggest that the natural variation of dead wood niches (decay stages, snag sizes, tree cavities and wood-inhabiting fungi species) must be maintained to efficiently conserve the whole saproxylic beetle fauna of beech forests. Also, intensive management may alter the specialised saproxylic beetle community even if the initial tree-species composition is maintained, which was the case in our study. For monitoring the ecological sustainability of forest management we must focus on threatened species. If structures alone are sampled then the amount of dead wood is the best indicator for a rich saproxylic beetle fauna.
117 citations
TL;DR: It is concluded that the protection of littoral and shoreline habitat integrity, with special emphasis on emergent and floating macrophytes, is critical to the conservation of lacustrine biodiversity.
Abstract: Human development of pond and lake shorelines may significantly impact native lacustrine biota including a variety of aquatic macroinvertebrate groups. In an effort to better understand the habitat associations and sensitivities of lacustrine damselflies (Odonata: Zygoptera), we sampled adults in littoral macrophyte habitat during two flight periods at 35 randomly selected pond and lake sites in southern Maine during 2000 and 2001. Data were also collected to help characterize water body, shoreline disturbance, and aquatic vegetation at each study site. Nonmetric multidimensional scaling was used for ordination of damselfly assemblages, and coordinates from the most stable solution were related to site variables using forward stepwise multiple regression. Our results suggest that the diversity and composition of damselfly assemblages is related to the abundance and richness of littoral zone macrophytes, extent of riparian disturbance, benthic substrate granularity, and lake productivity; all variables subject to anthropogenic degradation on excessively developed waterbodies. Additionally, we developed a Habitat Tolerance Index useful for distinguishing between relative habitat specialists and generalists from among a diverse assemblage of 19 lacustrine species. Finally, species-specific damselfly associations with multiple genera of floating and emergent macrophytes were assessed using both nonparametric correlation and multiplicative regression yielding significant relationships for 17 species, including two damselflies of global conservation concern (Enallagma laterale and E. pictum). We conclude that the protection of littoral and shoreline habitat integrity, with special emphasis on emergent and floating macrophytes, is critical to the conservation of lacustrine biodiversity.
87 citations
TL;DR: It is found that intensive summer grazing significantly reduces the vegetation height and is associated with significant reductions in bumblebee-food-plant abundance and bumblebees diversity.
Abstract: Many Tibetans who were formerly nomadic yak herders are settling near towns. However, yak remain a traditional symbol of wealth, which can lead to increased local stocking densities and severe over-grazing. We used belt-transect counts to study the area around Hongyuan in Sichuan. We find that intensive summer grazing significantly reduces the vegetation height and is associated with significant reductions in bumblebee-food-plant abundance and bumblebee diversity. For the significantly reduced bumblebee species, we identify the most frequently used and preferred bumblebee-food plants. For the food plants, we identify changes in absolute flower availability and changes in bumblebee visits. In particular, reductions in the bumblebees Bombus supremus, B. filchnerae, B. humilis and B. impetuosus are associated with reductions in flowers of the food plants Hedysarum and Saussurea.
82 citations
TL;DR: The analysis of patch occupancy indicates that it would be desirable to restore patches in close proximity to occupied sites, and traditional rough grazing regimes seem to be the most favourable tool for developing the necessary spatial and temporal heterogeneity in patches.
Abstract: We analysed the habitat preferences of adult stages and oviposition electivity of Melitaea aurelia in calcareous grasslands in the Diemel Valley (central Germany) to assess the key factors for successful management. Egg-laying and adult habitats of M. aurelia were more or less congruent. Oviposition electivity at the host plant (Plantago media) was best explained by a combination of host plant quantity and vegetation structure. Habitat quality, isolation and patch area explained 86% of the current patch occupancy of M. aurelia. With M. aurelia preferentially inhabiting transitional vegetation types, management requires a balance between abandonment and disturbance. Disturbances provide open soil that facilitates germination of the host plant Plantago media. On the other hand, immature and adult stages of M. aurelia perform best on calcareous grasslands with a high amount of host plants and low disturbance intensity. Traditional rough grazing regimes seem to be the most favourable tool for developing the necessary spatial and temporal heterogeneity in patches. The best results may be achieved by rotational grazing where only a subset of inhabited patches is grazed intensively each year. Our analysis of patch occupancy indicates that it would be desirable to restore patches in close proximity to occupied sites.
71 citations
TL;DR: In this article, the authors evaluated populations of Oedipoda caerulescens and Cicindela hybrida in relation to physical soil disturbance on four military training areas in Germany to determine if the military disturbance regime occurring there is conducive to the survival of the species and to provide insight into the nature of the disturbance that may be necessary as conservationists seek ways to maintain, establish or re-establish suitable habitat.
Abstract: Oedipoda caerulescens (blue-winged grasshopper) and Cicindela hybrida (northern dune tiger beetle) are protected insects in Germany and elsewhere. They are known to occur on sparsely vegetated, sandy soil. Populations of the two insects were evaluated in relation to physical soil disturbance on four military training areas in Germany to determine if the military disturbance regime occurring there is conducive to the survival of the species and to provide insight into the nature of the disturbance that may be necessary as conservationists seek ways to maintain, establish or re-establish suitable habitat. Adults of O. caerulescens exhibited statistically significant preference for areas with between 60% and 100% surface disturbance, corresponding to 50–70% plant cover, depending on the location. C. hybrida adults preferentially occupied areas with >40% disturbance resulting in an average of 61% plant cover. The results confirm suggestions that both species are disturbance-dependent. Military training areas represent some of the last, large remnants of sparse, dry, sandy grasslands in Europe. The nature of land-based military training creates suitable habitat patches as well as habitat connectivity needed for the maintenance of metapopulations. As a result, military training areas represent some of the last remaining vestiges of a habitat and disturbance regime that are highly favored by O. caerulescens and C. hybrida and other species with similar habitat requirements.
58 citations
TL;DR: Differences in the butterfly, bee, and forb community composition in linear and block prairie remnants, correlations between species diversity among butterflies, bees and forbs, and correlations of community similarity are examined, show that there need to be differences in conservation strategies for bees and butterflies to maintain both pollinator communities.
Abstract: Pollinators provide an important class of ecological services for crop plants and native species in many ecosystems, including the tallgrass prairie, and their conservation is essential to sustaining prairie remnants. In Iowa these remnants are typically either block-shaped or long, linear strips along transportation routes. In this study we examined differences in the butterfly, bee, and forb community composition in linear and block prairie remnants, determined correlations between species diversity among butterflies, bees and forbs in the 20 prairie remnants sampled, and examined correlations of community similarity among butterflies, bees and forbs. Correspondence analysis showed that distinct communities exist for butterflies and forbs in block versus linear sites and discriminant analysis showed that the bee and forb communities in block and linear sites can be distinguished on the basis of a few species. Diversity of one group was a poor predictor of diversity in another, except for a significant inverse relationship between bees and butterflies. These two pollinator taxa may be responding very differently to microhabitat components within fragmented ecosystems. Our studies show that there need to be differences in conservation strategies for bees and butterflies to maintain both pollinator communities.
55 citations
TL;DR: Spider species, such as Psechrus torvus and Tylorida culta, that contributed significantly to the dissimilarity between undisturbed and disturbed rainforest sites, and rainforest and shade-coffee sites were identified that serve as useful indicators of habitat alteration.
Abstract: Studies on the effects of tropical rainforest fragmentation and disturbance have often focussed on plants and vertebrates such as birds and mammals and seldom on invertebrates, despite the latter being among the most biologically diverse groups in these ecosystems. Spiders are one such group of invertebrate predators that are known to be sensitive indicators of environmental change in tropical ecosystems. The present study assesses the spider community structure and responses to rainforest fragmentation and degradation and conversion to shade-coffee plantations in the Anamalai hills, southern Western Ghats, India. Ten rainforest fragments ranging in size from 11 ha to 2,600 ha under varying levels of degradation within the Indira Gandhi Wildlife Sanctuary and private lands of the Valparai plateau, and two shade-coffee plantation sites were sampled for spiders using visual searches along time-constrained belt transects between January and May 2005. Within a total sampled area of 5.76 ha, 4,565 individual spiders (4,300 detections) belonging to 156 morphospecies within 21 families and 8 functional groups were recorded. The estimated total number of understorey spider species in the study area was 192 (±5.15 SD) species, representing around 13% of the total number of spider species so far described from India. Overall spider density, species richness, and species density showed no trend in relation to fragment area across all sites. Specific comparisons among undisturbed sites indicated however that high altitude sites had fewer species than mid-altitude sites and fragments had fewer species than relatively larger continuous forest sites. In contrast to the lack of trend in overall species richness and abundance, species composition changed substantially in relation to habitat alteration and altitude. Cluster analysis of Bray-Curtis similarities among sites in spider species composition revealed four distinct clusters: high altitude undisturbed sites, mid-altitude disturbed sites with an undisturbed mid altitude site, mid-altitude highly disturbed sites with a disturbed site, and shade-coffee plantation sites. Spider species, such as Psechrus torvus and Tylorida culta, that contributed significantly to the dissimilarity between undisturbed and disturbed rainforest sites, and rainforest and shade-coffee sites were identified that serve as useful indicators of habitat alteration.
54 citations
TL;DR: In this article, the authors used site-occupancy models to explore the seasonal patterns in detection probability of four California butterflies using Pollard walks and estimated the detection probability (the probability of recording a species during a single transect walk, given it is present) of four species.
Abstract: Monitoring protocols should be designed to maximize the probability of detecting target species with limited resources. Most species are imperfectly detected, hence, they will often be overlooked at sites where they actually occur, resulting in false-negative errors (i.e. false absences). Uncertain detection of target species has profound implications for conservation, but can be dealt with by using adequate survey designs and statistical models. Butterflies often are monitored with repeated, fixed-route transect counts (Pollard walks). Even though this survey method is widely used in temperate regions, its efficiency in terms of detection probability has never been rigorously assessed in part owing to a lack of suitable analysis methods. Here, I use site-occupancy models to explore the seasonal patterns in detection probability of four California butterflies using Pollard walks. In an effort to inventory the butterfly fauna in two natural areas in the eastern foothills of the Santa Cruz mountains (California), I surveyed twelve 250 m long transects weekly for 22 weeks. I estimated the detection probability (the probability of recording a species during a single transect walk, given it is present) of four species. The probability of detecting each species depended mostly on the monitoring week. Average detection probability across the season was 64% for Cercyonis pegala, 56% for Limenitis lorquini, 76% for Euphydryas chalcedona, and 50% for Lycaena arota. Based on the mean detection probability, I then inferred the number of visits necessary to be statistically confident that a given species was indeed absent from a transect where it was not observed (i.e. obtaining a false absence rate <5%). Knowledge of detection probabilities is fundamental to the optimal design of monitoring programs and the interpretation of their results. The methods applied in this study provide an efficient and evidence-based method to optimally allocate butterfly monitoring resources across space (number of transects) and time (number and timing of visits).
48 citations
TL;DR: It is suggested that communities of trap-nesting wasps in forests are influenced more by the local habitat conditions than by forest loss.
Abstract: We investigated changes in the communities of trap-nesting Hymenoptera in forests in relation to forest loss on a landscape scale and understory conditions on a local habitat scale. Two specific questions were addressed. (1) Do the communities change with degrees of forest loss? (2) Do the communities change with varying local environmental conditions of understory habitats? The study was made in a landscape characterized by distributed forest patches within intensively managed agricultural surroundings. We deployed trap-nests at eight randomly selected sites in forests in summer. To quantify forest loss, the amount of forest coverage was calculated using GIS. To indicate local habitat conditions, the species richness of understory flowering plants was used. All together, 12 species of wasps and no bees were captured. Regression analyses showed that both abundance and species richness of the wasps were not significantly related to forest coverage. However, abundance of trap-nesting wasps was significantly related to species richness of understory plants, but species richness of the wasps was not significantly related to the plants. These results suggest that communities of trap-nesting wasps in forests are influenced more by the local habitat conditions than by forest loss.
TL;DR: The Southern Ocean Islands (SOI) have an exceptionally high conservation status, and human activity on the islands is low by comparison with more tropical islands as mentioned in this paper, however, overexploitation, pollution and habitat destruction have had little influence on the invertebrate biotas of the islands, although over-exploitation of pelagic species has the potential for an indirect influence via reduction of nutrient inputs to the terrestrial systems.
Abstract: The Southern Ocean Islands (SOI) have an exceptionally high conservation status, and human activity on the islands is low by comparison with more tropical islands In consequence, overexploitation, pollution and habitat destruction have had little influence on the invertebrate biotas of the islands, although overexploitation of pelagic species has the potential for an indirect influence via reduction of nutrient inputs to the terrestrial systems By contrast, invasive alien species, the local effects of global climate change, and interactions between them are having large impacts on invertebrate populations and, as a consequence, on ecosystem functioning Climate change is not only having direct impacts on indigenous invertebrates, but also seems to be promoting the ease of establishment of new alien invertebrate species It is also contributing to population increases of invertebrate alien species already on the islands, sometimes with pronounced negative consequences for indigenous species and ecosystem functioning Moreover, alien plants and mammals are also affecting indigenous invertebrate populations, often with climate change expected to exacerbate the impacts Although the conservation requirements are reasonably well-understood for terrestrial systems, knowledge of freshwater and marine near-shore systems is inadequate Nonetheless, what is known for terrestrial, freshwater and marine systems suggests that ongoing conservation of SOI invertebrates requires intervention from the highest political levels internationally, to slow climate change, to local improvements of quarantine measures to reduce the rates and impacts of biological invasions
TL;DR: It is re-iterated the importance of documenting the transfer and post-release monitoring for all insect transfers, both for biogeographical reasons and to provide information to improve future transfers.
Abstract: Establishing new populations by transferring founder individuals from source populations has been effective for managing the recovery of many threatened species including some weta (Orthoptera: Anostostomatidae) in New Zealand. These large-bodied flightless insects are ‘flagship species’ for insect conservation in New Zealand and many are rare or threatened. The declining abundance of most weta species, particularly giant weta, can be attributed to the introduction of mammalian predators, habitat destruction, and habitat modification by introduced mammalian browsers. New populations of some weta have been established in locations, particularly on islands, where these threats have been eliminated or severely reduced in order to reduce the risk of extinction. Some populations were established to provide food for endemic vertebrates, ecosystem restoration and ready access for the general public. We illustrate how methods for both transferring weta and monitoring them have become more sophisticated by using a series of case studies. Other transfers of weta not included in the case studies are also summarised. We conclude by re-iterating the importance of documenting the transfer and post-release monitoring for all insect transfers, both for biogeographical reasons and to provide information to improve future transfers.
TL;DR: The Chalkhill Blue Polyommatus coridon has been identified as a Species of Conservation Concern in the UK Biodiversity Action Plan due to a greater than 25% decline in range size since the 1950s, with losses due to the combined effects of habitat destruction, agricultural intensification and neglect as discussed by the authors.
Abstract: The Chalkhill Blue Polyommatus coridon is a widespread butterfly of lowland calcareous grassland in southern Britain and is considered a good indicator of habitat condition. Polyommatus coridon has been identified as a Species of Conservation Concern in the UK Biodiversity Action Plan due to a greater than 25% decline in range size since the 1950s, with losses due to the combined effects of habitat destruction, agricultural intensification and neglect. Analysis of annual butterfly monitoring data (transects) collected at 161 sites from 1981 to 2000 show a three-fold population recovery had occurred. The increases were at established sites, with no re-colonisations or range expansion detected. The 1980s population increase coincided with increases across the species range in stock and rabbit Oryctolagus cuniculus grazing, as well as greater protection and management of sites through protected areas and nature reserves. During the 1990s agri-environment schemes were thought to be the main conservation and policy mechanism driving the favourable conservation status of P. coridon, by facilitating appropriate habitat restoration and management. Weather played a part in the species recovery, with warm, but wet summers associated with increases in abundance. The research provides strong evidence of an important conservation success with the UK Biodiversity Action Plan, with implications for other specialist biodiversity.
TL;DR: Orthoptera were monitored on field edge public footpaths on the east (leeward) and west (windward) side of hedgerows in Chelmsford, UK, in 2006 as mentioned in this paper.
Abstract: Orthoptera were monitored on field edge public footpaths on the east (leeward) and west (windward) side of hedgerows in Chelmsford, UK, in 2006. A total of 6 species were recorded from footpaths on the leeward side of hedgerows probably due to the shelter from the prevailing westerly winds provided by the trees and shrubs. On the windward side of hedgerows species richness and abundance of Orthoptera were reduced (only 4 species were recorded). It is suggested that shelter from the wind and the exposure to early morning sunlight for Orthoptera on the east side of hedgerows are important factors governing their occurrence on farmland. Many replicates had Environmental Stewardship (ES) scheme field margins adjacent but they did not affect Orthoptera species richness or abundance.
TL;DR: Continuing existence of the population depends on nutrient-poor conditions for a diverse ground flora and a sparse tree canopy, and the herb layer is threatened by soil enrichment due to the demise of traditional grazing, litter raking and grass mowing in woodlands.
Abstract: The distribution of Lopinga achine (Lepidoptera Nymphalidae, Satyrinae) in the Czech Republic has declined from thirty grid squares before 1950 to just one extant population, restricted to a single area of deciduous woodland. A review of historical sites shows that this species used to occur in various types of deciduous woodland with a relatively sparse canopy maintained by coppicing and/or grazing. The extant population inhabits mature woodland with a mean canopy cover of 60% (quartiles 50% and 65%), sparse shrubs and a species-rich herb layer containing plant species requiring dry, warm and nutrient-poor conditions. The larval host plants are the fine-leafed sedges, Carex fritschii and C. michelii. In 2006, the total population contained about 10,000 adults but this may be an over-estimate, biased by male behaviour. Measurements of adult mobility, well approximated by an inverse-power function, suggested that all existing colonies are interconnected by dispersal. Continuing existence of the population depends on two conditions; nutrient-poor conditions for a diverse ground flora and a sparse tree canopy. While canopy closure is gradually increasing, the herb layer is threatened by soil enrichment due to the demise of traditional grazing, litter raking and grass mowing in woodlands. Any future management to favour Lopinga achine should include both measures to maintain a sparse canopy and measures to export biomass, such as raking or mowing of ground flora or, preferably, re-establishment of grazing.
TL;DR: In this article, the status of the butterfly fauna on the islands was examined using principal components analysis and regression modelling, and the authors found that a large fraction of the European butterfly species are found on islands (63.4% on small islands) comprising some 6.2% of the land area of Europe.
Abstract: 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.
TL;DR: Molecular approaches must be used with caution for conservation genetics which is best accomplished using large sample sizes over extensive geography in addition to data from multiple loci, such as introgressive hybridization.
Abstract: The increasing popularity of molecular taxonomy will undoubtedly have a major impact on the practice of conservation biology. The appeal of such approaches is undeniable since they will clearly be an asset in rapid biological assessments of poorly known taxa or unexplored areas, and for discovery of cryptic biodiversity. However, as an approach for diagnosing units for conservation, some caution is warranted. The essential issue is that mitochondrial DNA variation is unlikely to be causally related to, and thus correlated with, ecologically important components of fitness. This is true for DNA barcoding, molecular taxonomy in general, or any technique that relies on variation at a single, presumed neutral locus. Given that natural selection operates on a time scale that is often much more rapid than the rates of mutation and allele frequency changes due to genetic drift, neutral genetic variation at a single locus can be a poor predictor of adaptive variation within or among species. Furthermore, reticulate processes, such as introgressive hybridization, may also constrain the utility of molecular taxonomy to accurately detect significant units for conservation. A survey of published genetic data from the Lepidoptera indicates that these problems may be more prevalent than previously suspected. Molecular approaches must be used with caution for conservation genetics which is best accomplished using large sample sizes over extensive geography in addition to data from multiple loci.
TL;DR: Although butterfly behavior appeared to be affected by the change in sward height on the treatment edge, there was no evidence for the edge causing a disproportionate egg load, and invasion and dominance by A. elatius appeared to diminish host plant apparency which may result in overloading of eggs on conspicuous host plants.
Abstract: Fender’s blue butterfly is an endangered species restricted to fragmented, grassland remnants that are becoming increasingly dominated by tall, invasive grasses in western Oregon, USA. I performed a removal experiment to assess the impacts of structural degradation accompanying the invasion of Arrhenatherum elatius, tall oat grass, on butterfly fitness and fitness related behaviors. Clipping of A. elatius to native grass sward height resulted in 2.5–5 times as many eggs laid per leaf of host plant. Both male and female butterflies basked more frequently in areas removed of A. elatius inflorescences and upon encountering the treatment edge butterflies had a high rate of return into a large area removed of the grass inflorescences. Although butterfly behavior appeared to be affected by the change in sward height on the treatment edge, there was no evidence for the edge causing a disproportionate egg load. Invasion and dominance by A. elatius appeared to diminish host plant apparency which may result in overloading of eggs on conspicuous host plants, increased incidence of emigration, and a decrease in the likelihood of colonization because female butterflies appeared indifferent to larval resources beneath A. elatius inflorescences. Dominance of natural shortgrass prairies by tall stature grasses like A. elatius may be an insidious form of habitat degradation for grassland Lepidoptera worldwide, but it may go largely unnoticed because larval and adult resources can persist under the unnaturally tall grass canopy.
TL;DR: Optimal management strategies depend on the abiotic and biotic conditions and conservation priorities for the given region and habitat type, and management regimes that promise to sustain suitable H. lucina habitat at a landscape-level are suggested.
Abstract: In order to improve our understanding of habitat preferences and optimal management of open woodland in- sects, we analyse patch occupancy and oviposition electivity of the endangered Duke of Burgundy butterfly, Hamearis lucina, in three regions across German habitat types. Some newly available forest clearings created by a severe winter storm in the Schonbuch region were colonised within 2 years, whereas some suitable patches remained unoccupied for several years. We discuss how small population sizes, limited patch connectivity, and habitat quality may contribute to such an intermediate colonisation power. Across study regions, we document differences in oviposition site elec- tivity. On calcareous grassland in the Diemeltal, shaded Primula plants on western slopes were preferentially used, probably to avoid desiccation of the natal food plant. To the contrary, sun-exposed Primula stands were preferred in forest clearings in the Schonbuch and calcareous fens in the Allgau. In these regions, the risk of desiccation is low, but the overall cool and moist microclimate conditions may hamper larval development in shaded conditions, favouring oviposition at sites with maximum exposition to solar radiation. Optimal management strategies depend on the abiotic and biotic conditions and conservation priorities for the given region and habitat type, and we suggest manage- ment regimes that promise to sustain suitable H. lucina habitat at a landscape-level.
TL;DR: Estimates of population size obtained through sampling of queen offspring is significantly larger than that obtained by sampling drones at DCAs, and this difference may be due to the more extensive flying range of queens compared with drones on mating flights.
Abstract: Estimating the population size of social bee colonies in the wild is often difficult because nests are highly cryptic. Because of the honeybee (Apis mellifera) mating behaviour, which is characterized by multiple mating of queens at drone congregation areas (DCA), it is possible to use genotypes of drones caught at these areas to infer the number of colonies in a given region. However, DCAs are difficult to locate and we assess the effectiveness of an alternative sampling technique to determine colony density based on inferring male genotypes from queen offspring. We compare these methods in the same population of wild honeybees, Apis mellifera scutellata. A set of linked microsatellite loci is used to decrease the frequency of recombination among marker loci and therefore increase the precision of the estimates. Estimates of population size obtained through sampling of queen offspring is significantly larger than that obtained by sampling drones at DCAs. This difference may be due to the more extensive flying range of queens compared with drones on mating flights. We estimate that the population size sampled through queen offspring is about double that sampled through drones.
TL;DR: Using morphology, mitochondrial DNA and microsatellites to characterize the endemic population of honey bees in the Landes region of Southwest France yielded different degrees of discrimination of native and imported colonies and provided a powerful suite of tools for local resource managers.
Abstract: A population of honey bees (Apis mellifera mellifera L.) with an annual colony brood cycle adapted to a locally abundant floral source in the Landes region of Southwest France is the subject of genetic conservation efforts. This population is maintained by local beekeepers in an area that experiences both an annual seasonal influx of non-local colonies and the permanent culture of imported stock. However, some colonies native to the Landes do not have the adapted brood cycle and their status as ecotypic are in question. The present study used morphology, mitochondrial DNA and microsatellites to characterize the endemic population and suggests further genetic conservation strategies. These methods yielded different degrees of discrimination of native and imported colonies and provided a powerful suite of tools for local resource managers. Colonies from the Landes could be differentiated from non-local French A. m. mellifera populations using morphometric analysis, and from non-native and reference populations using mtDNA and microsatellites. Seven morphological characters were identified by discriminant analysis as informative for delineating the Landes ecotype from other A. m. mellifera populations. Mitochondrial haplotypes for the population were characterized and five microsatellite loci were found to be informative in characterizing the Landes population. Asymmetric gene flow detected with microsatellite alleles was observed to be 5.5–5.9% from imported to native stocks of honey bees while introgression of native microsatellite alleles into imported colonies was 21.6%.
TL;DR: In this paper, the authors 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.
Abstract: 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.
TL;DR: In this article, the authors sampled dung beetles in two undisturbed habitats, deciduous forest and semideciduous forests, and two disturbed habitats, secondary forest and open area habitat, in the Chamela-Cuixmala region of western Mexico.
Abstract: Dung beetles (Scarabaeinae) are conspicuous components in most terrestrial ecosystems, performing important ecological functions and services. Being sensitive to several types of disturbance, they have been successfully used as indicators of habitat change. Dung beetle communities in tropical rainforests have been well studied, but considerably less information is available for tropical dry forests. In this study I sampled dung beetles in two undisturbed habitats, deciduous forest and semideciduous forest, and two disturbed habitats, secondary forest and open area habitat, in the Chamela-Cuixmala region of western Mexico. Dung beetle species with high indicator value for each habitat were identified. Beetle abundance, observed species richness and estimated species richness were similar in the three forest habitats, but significantly lower in the open area habitat. A more detailed analysis of species-specific abundances in the three forest habitats revealed some differences. Transects of one of the undisturbed habitats, the deciduous forest, were more similar to the non-adjacent transects of disturbed secondary forest, than to the adjacent undisturbed semideciduous forest transects. Unlike studies in other tropical sites that have found a decrease in equitability in Scarabaeinae assemblages between undisturbed forest and disturbed habitat (particularly open habitats), in the Chamela-Cuixmala region all four habitats showed similar low equitability in community structure, with two or three very dominant species.
TL;DR: It is suggested that transect counts need to be fully validated before the data is used to monitor changes of butterfly populations at individual sites.
Abstract: Multiple transect counts following Butterfly Monitoring Scheme (UKBMS) guidelines and Jolly–Seber estimates of population size were used to monitor the abundance of second generation Lasiommata megera on a single site in southern England. The two methods resulted in different patterns of emergence being detected. The proportion of the population (estimated by Jolly–Seber) recorded with transect counts depended on the time of day and weather with afternoon transect counts best recording the trend in abundance over the flight period, but even then counts recorded a variable fraction of the population (6.2–51.3%). Increasing the frequency with which transect counts are carried out per week reduced variation and increased the fit of transect counts to Jolly–Seber generated population estimates. However, indices of abundance generated from randomly selected transect counts for L. megera within sampling weeks varied 4-fold and indices for other butterfly species were also highly variable. For L. megera, transect count variability is attributed to non-representative placement of the transect route and changes in the behaviour and spatial distribution in relation to population size and season. We suggest that transect counts need to be fully validated before the data are used to monitor changes of butterfly populations at individual sites.
TL;DR: Behavioural observations reveal that this species is very different from other Australian stick insects, but similar in many ways to overseas members of the Eurycanthinae.
Abstract: The Lord Howe Island Stick Insect (Dryococelus australis: Phasmatodea: Phasmatidae: Eurycanthinae) is a large, flightless stick insect once thought to be extinct but rediscovered on an island (Balls Pyramid) near Lord Howe Island in 2001. A captive population at Melbourne Zoo is now in its fourth generation and aspects of the biology of the species are discussed. Observations focussed on the eggs as indicators of the health of the population and inbreeding depression, but included data on the juveniles where possible. Behavioural observations reveal that this species is very different from other Australian stick insects, but similar in many ways to overseas members of the Eurycanthinae. Veterinary interventions and post mortems have provided substantial information about the captive population and its environmental stresses, and have wider implications for captive invertebrate populations, particularly those involved in conservation programs. Evidence of inbreeding and the conservation significance of this species is discussed in context with other programs and their implications.
TL;DR: In this article, Lencinas et al. presented the Consejo Nacional de Investigaciones Cientificas y Tecnicas (CICTE) with the following conclusions:
Abstract: Fil: Lencinas, Maria Vanessa. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Austral de Investigaciones Cientificas; Argentina
TL;DR: Mowing once a year, in the second half of September, after the larvae have left their host plants, enhances the abundance of Myrmica ants in the meadows, and would be the best management compromise for all three species.
Abstract: Maculinea butterflies obligatory parasitize certain species of Myrmica ants. Thus, the presence of the host ant species is a limiting factor for the survival of a Maculinea population. Here, we analyse the influence of vegetation structure and ground temperature on ant diversity and abundance on Maculinea habitats, with the final aim of identifying the environmental variables determining patterns of variation in species composition in order to recommend a mowing regime that will promote our three target species: Maculinea teleius, M. nausithous and M. alcon. Experimental plots with different mowing regimes were established at eight sites in South-Eastern Germany, a region which still contains a number of relatively large, stable populations of these threatened butterfly species. Among the seven different ant species recorded, four belong to the genus Myrmica (M. scabrinodis, M. rubra, M. ruginodis and M. vandeli). Among these, M. scabrinodis results most abundant at all sites. In a CCA analysis of environmental variables recorded at the studied plots, ant species diversity appears largely determined by litter cover, mean temperature, and mean grass cover. Mowing once a year, in the second half of September, after the larvae have left their host plants, enhances the abundance of Myrmica ants in the meadows, and would be the best management compromise for all three species.
TL;DR: Using museum collection data to estimate measures of species rarity and then to relate these measures to extinction risk provides a good basis for identifying species that are most in need of conservation at a particular scale.
Abstract: This paper attempts to use museum collection data to estimate measures of species rarity and then to relate these measures to extinction risk. For this purpose, 170 taxa (138 species and 32 subspecies) of tenebrionid beetles from 32 Aegean Islands (Greece) were considered. For each taxon, rarity was evaluated as geographic distribution (mean incidence on islands in the archipelago), potential habitat exploitation (total area of the islands occupied on the total area of the study system) and contactability (number of decades of taxon’s records on the total number of decades of assumed persistence from 1870 to 2000). All of these indices were correlated to each other. Whether expressed in terms of range size or habitat exploitation rarity was a major determinant of a species’ risk of extinction (evaluated as extinction decade). Thus, the designation of rarity provides a good basis for identifying species that are most in need of conservation at a particular scale.
TL;DR: The results of a 2-year mark-release-recapture study on two neighbouring populations in Germany imply a high vulnerability of the species, provide basic methodological information for an implementation of the EC Directive and for further research, and highlight the necessity to enlarge populated habitats.
Abstract: The declining European ground beetle Carabus variolosus, an indicator of undisturbed woodland brooks and swamps, is listed in the EU Species and Habitats Directive. Little is known about this flightless and endangered beetle, apart from its distribution range and habitat stenotopy. We present the results of a 2-year mark-release-recapture study on two neighbouring populations in Germany, which investigated basic parameters of population ecology that may be influential in the persistence of the beetle. Extremely small population sizes were the key findings. Since population densities corresponded to those of typical Carabus species, the size of the habitats was most probably the limiting factor. The risk of heavy losses during offspring development and hibernation may be alleviated by the considerable proportion of C. variolosus reproducing in more than 1 year. The fact that we did not recapture any marked specimens from the neighbouring population suggests a very limited dispersal power. The results imply a high vulnerability of the species, provide basic methodological information for an implementation of the EC Directive and for further research, and highlight the necessity to enlarge populated habitats.