Showing papers in "Insect Conservation and Diversity in 2008"

Designing for conservation of insects in the built environment

Abstract: The conservation of insects is not a priority for most urban dwellers, yet can be accomplished in urban settings by the careful design of urban nature. Our goal is to foster cross-talk between practitioners of insect conservation biology who develop the knowledge base and professional design practitioners who are poised to apply this knowledge in designs and management plans for urban green space. The collaborative product promises a built environment that promotes human well-being and urban beauty while maximizing the potential for the conservation of insects. 2. There is precedence for collaboration between science and design communities to achieve conservation, and existing professional and civic organizations offer a structure to formalize and expand collaboration. Design professionals, particularly landscape architects, are trained to support insect conservation in the urban landscape through land planning and ecological site design. 3. Ecological site design is based in principles of sustainability and so must address the well being of humans and nature simultaneously. This powerful approach for insect conservation is illustrated in examples from around the world focusing on roadway-easement corridors, stormwater management areas, and greenroofs. 4. To improve insect conservation and its public support we offer recommendations, organized in response to cultural aspects of sustainability. Considerations include: a) social drivers for support of conservation practices, b) public perception of urban space, c) applying conservation biology principles in urban areas, and d) merging insect conservation goals with human cultural demands.

Rapid biodiversity assessment of spiders (Araneae) using semi-quantitative sampling: a case study in a Mediterranean forest

Abstract: . 1A thorough inventory of a Mediterranean oak forest spider fauna carried out during 2 weeks is presented. It used a semi-quantitative sampling protocol to collect comparable data in a rigorous, rapid and efficient way. Four hundred and eighty samples of one person-hour of work each were collected, mostly inside a delimited 1-ha plot. 2Sampling yielded 10 808 adult spiders representing 204 species. The number of species present at the site was estimated using five different richness estimators (Chao1, Chao2, Jackknife1, Jackknife2 and Michaelis–Menten). The estimates ranged from 232 to 260. The most reliable estimates were provided by the Chao estimators and the least reliable was obtained with the Michaelis–Menten. However, the behavior of the Michaelis–Menten accumulation curves supports the use of this estimator as a stopping or reliability rule. 3Nineteen per cent of the species were represented by a single specimen (singletons) and 12% by just two specimens (doubletons). The presence of locally rare species in this exhaustive inventory is discussed. 4The effects of day, time of day, collector experience and sampling method on the number of adults, number of species and taxonomic composition of the samples are assessed. Sampling method is the single most important factor influencing the results and all methods generate unique species. Time of day is also important, in such way that each combination of method and time of day may be considered as a different method in itself. There are insignificant differences between the collectors in terms of species and number of adult spiders collected. Despite the high collecting effort, the species richness and abundance of spiders remained constant throughout the sampling period.

Dragonfly community re‐organisation in boreal forest lakes: rapid species turnover driven by climate change?

Abstract: . 1 Climate change affects many ecosystems on earth. If not dying out or migrating, the species affected have to survive the altered conditions, including changes in community structure. It is, however, usually difficult to distinguish changes caused by a changing climate from other factors. 2 Forestry is considered to be the major disturbance factor in Swedish forests. Here, we use forest lake data sets from 1996 and 2006 which include species abundance data for dragonfly larvae, water plant structure, forest age and forestry measures during a period of 25 years: from 1980 to 2005. Hence, we were able to discriminate between forestry effects and changes in species composition driven by recent climate change. 3 We explored effects on regional species composition, species abundance and ecosystem functions, such as changes in niche use, utilising dragonflies (Odonata) as model organisms. 4 Our results show that dragonflies react rapidly to climate change, showing strong responses over such a short time span as 10 years. We observed changes in both species composition and abundance; former rare species have become more frequent and now occur in lakes of a wider quality range, while former widespread species have become more selective in their choice of waters. The new communities harbour about the same number of species as before, but seen from a regional perspective, diversity is reduced. 5 We predict that the altered species composition and abundance might raise new demands in conservation planning as well as altering the ecological functions of the aquatic systems.

Long-term land-use changes and extinction of specialised butterflies

Abstract: 1. Land-use change in 450 ha in southern Sweden between 1814 and 2004 was recorded. Butterflies and burnet moths were surveyed in 1904–1913 and 2001–2005. 2. We explore if local extinctions were related to land-use changes and species attributes. 3. Land use changed drastically over the 190-year period, and the largest relative change occurred for hay meadows with late harvest, which decreased from 28% to 0%. The area changed from grasslands and grazed forests to being dominated by timber forests. Previous open grazed mixed woodlands changed to spruce plantations with clear-cuts. 4. Of the 48 resident butterfly and burnet moths found a century ago, 44% have become extinct. The extinct Aporia crataegi, Colias palaeno, and Leptidea sinapis were abundant 100 years ago and had their highest densities in flower-rich glades in forest, a habitat which no longer exists. 5. The butterfly extinctions could be predicted from species-specific attributes as a short flight length period (P < 0.02), narrow habitat breadth (P < 0.02), small distribution area in Europe (P = 0.033) and possibly larvae food plant nitrogen class (P < 0.06). In a multiple logistic regression, the flight length period was the only significant variable because the independent variables were intercorrelated. 6. We conclude that the most important factor explaining the high extinction rate is that flower-rich habitats have disappeared from both woodlands as well as from open farmlands. The most sensitive species are specialised species with a short summer flight which have gone extinct. Only the most unspecialised species still persist in the current landscape. (Less)

Forest management effects on carabid beetle communities in coniferous and broadleaved forests: implications for conservation

Abstract: Carabid beetles (Carabidae, Coleoptera) were sampled by pitfall trapping to determine the effects of plantation forest management on beetle abundance, diversity and community composition. Five habitats were chosen for study to represent the different environments created by the clear‐fell and re‐plant forestry cycle: clear‐fell, new‐plant, mixed (conifer and broadleaved) and mature stage conifer plantation. The results from these sites were compared with semi‐natural deciduous woodland. Beetles were trapped for 6 weeks during June and July 2005. At each site, a range of environmental parameters were measured; soil pH, soil organic matter content, soil water content, percentage canopy cover, amount of dead wood, leaf‐litter depth, tree species present, tree diameter at breast height and percentage cover of ground vegetation. These were used to interpret differences in carabid abundance, diversity and community assemblage. Beetle abundance was highest in the deciduous habitat, but species diversity was not significantly different between any of the sites, except the clear‐fell habitat which was less diverse. Carabid community assemblages of forest specialist, forest generalist and open‐habitat species were investigated. Only the broadleaved deciduous woodland contained large populations of forest specialist species. These results suggest inclusion of purely broadleaved stands in the forest landscape is necessary to maximise diversity at the landscape scale and enhance the overall conservation potential of managed forest land. Within habitats the amount of dead wood, number of tree species present, percentage canopy cover and leaf‐litter depth were significant determinants of carabid abundance and diversity.

The effectiveness and optimal use of Malaise traps for monitoring parasitoid wasps

Abstract: . 1 Parasitoid wasps are species-rich and likely to be sensitive indicators of environmental change. Malaise traps are widely used for sampling certain taxa of parasitic Hymenoptera, but little is known about how they should best be used to monitor the community at an individual site. 2 To investigate the effects of sample duration, trap location and replication on the parasitoid assemblage, we sampled four ichneumonid subfamilies (Hymenoptera: Ichneumonidae) intensively using Malaise traps in two farm woods in the Vale of York, UK. 3 Species accumulation curves showed that even with 16 Malaise traps per wood, the community is incompletely sampled. Despite this, we caught up to 28% of all UK species in a single wood, implying that local parasitoid diversity may be very high. 4 Abundance and species richness of parasitoids differed significantly between sample periods (fortnights) and between traps, but did not differ overall between core and edge locations. 5 Parasitoid community composition differed between core and edge traps, but differences were much stronger in one wood than the other. One subfamily, the Poemeniinae, was found predominantly in edge locations. Catch differences became greater with increasing distance between traps. 6 The previous year, two traps in each of the same woods caught only half as many species, but species abundance was positively correlated between years. 7 Our results suggest that a small number of traps can contain useful information about the parasitoid community but is likely to seriously underestimate total species richness. To achieve extensive species coverage, sampling should continue over several weeks, with widely separated traps sampling both core and edge locations. Our focal taxa should prove excellent for monitoring the effects of environmental change on biodiversity.

Water‐energy and the geographical species richness pattern of European and North African dragonflies (Odonata)

Abstract: . 1 Environmental correlates of broad-scale patterns of Odonata species richness were studied in Europe and part of northern Africa using 220 × 220-km gridded data. Relationships with 11 environmental variables were tested using multiple regression. 2 Two models were constructed: (i) for the entire data set covering both Europe and northern Africa, and (ii) only for Europe. 3 Across both regions, actual evapotranspiration had the strongest relationship with richness, followed by weaker associations of potential evapotranspiration (a concave polynomial) and summer vegetation index (a positive linear relationship). Within Europe the strongest predictor was a concave polynomial of potential evapotranspiration, followed by vascular plant species richness (a positive relationship) and annual precipitation (a concave polynomial). 4 A test of metabolic theory identified strong non-linearity in the temperature-richness relationship, and geographically weighted regression indicated consistency with the theory in a very limited part of Europe. 5 The results are most consistent with the hypothesis that broad-scale species richness patterns are primarily determined by water–energy balance, similar to many fully terrestrial insect groups.

Elevated atmospheric carbon dioxide and ozone alter forest insect abundance and community composition

Abstract: Human-induced climate changes threaten the health of forest ecosystems. In particular, carbon dioxide (CO2) and tropospheric ozone (O3) will likely have significant but opposing impacts on forests and their associated insect communities. Compared with other animal groups, insect communities are expected to be especially sensitive to changes in global climate. 2. This study examined the effects of elevated CO2 and O3 (eCO2 and eO2) individually and in combination on the abundance, diversity and composition of forest insect com- munities. Insects were sampled using yellow pan traps in an aggrading aspen-birch forest at the Aspen Free Air CO2 Enrichment (FACE) site in northern Wisconsin, USA. We trapped for 24 h every 10 -15 days throughout the summers (June to September) of 2000 -2003. 3. We examined 47 415 insects from 4 orders and 83 families. Elevated CO2 reduced abundance of phloem-feeding herbivores and increased abundance of chewing herbivores, although results were not statistically significant. Enriched CO2 increased numbers of some parasitoids. The effects of eO3 on insect abundance were generally opposite those of eCO2. No significant differences in arthropod family richness were found among treatments. However, eCO2, eO3, or both significantly affected insect community composition in all years. 4. Carbon dioxide and tropospheric ozone have the potential to alter significantly forest insect communities. Feeding guild may strongly influence insect response to environmental change and may provide the best opportunity to generalise for conservation efforts. Because insect communities influence forest health and ecosystem services, continued research on their response to global change is critically important to forest management and conservation.

Grazing impacts on moth diversity and abundance on a Scottish upland estate

Abstract: . 1 Livestock grazing is the most important direct management impact on grasslands in upland areas of the UK. For phytophagous species, such as Lepidoptera, the impact is primarily through grazing altering the species composition and structure of the vegetation. However, specific impacts related to different grazing regimes are not well understood for this group of insects. 2 Within a replicated controlled grazing experiment, nocturnal adult moths were sampled by light trapping in the fifth year after establishment. Sampling effort was standardised between the four grazing treatments by simultaneously using identical traps in each treatment. 3 The highest-intensity grazing treatment produced the lowest moth abundance and species richness. Ungrazed and low-intensity sheep grazing treatments produced the highest moth abundance and species richness. 4 Moths that feed exclusively on graminoids and moths that overwinter as larvae were disproportionately well represented in the ungrazed treatment. 5 A sub-set of species for which large declines have recently been documented in the UK were most abundant in the ungrazed treatment. However, they made up the largest proportion of the overall assemblage in the high-intensity grazing treatment. 6 Increased grazing inversely affects moth abundance and species richness. However, effects are not even across all moth species. An absence of grazing is likely to negatively affect the abundance of some moths, especially those that overwinter in the egg stage.

Response of dung beetle assemblages to landscape structure in remnant natural and modified habitats in Southern Mexico

Abstract: . 1 To provide reliable tools for landscape management in tropical regions, it is important to recognise the emergent properties of landscape heterogeneity and to understand their influence on different components of biodiversity. 2 The effects of habitat type, patch size and shape, canopy cover, distance between habitats, and elevation were examined on the partitioned diversity (alpha, beta and gamma) of dung beetles in a transformed landscape in southern Mexico. 3 In total, 4109 individuals belonging to 28 species of dung beetle were recorded in the entire landscape. Alpha diversity was similar among habitats, although species composition was more similar between forest remnants and living fences than between living fences and pastures. Beta diversity was related to differences in elevation and distance between habitats. The distance between fragments was significantly correlated with the mean number of beetle captures and species richness per site. Gamma diversity depended more on species turnover (beta diversity) than on local species richness. 4 In general, living fences and pastures with trees, and small forest patches retain a significant proportion of the fauna typically associated with pristine forest habitats. The remaining tracts of forest, along with the contemporary landscape elements may offer suitable habitats for future recolonisation by other insect species in heavily disturbed landscapes in tropical Mexico.

Insect conservation: finding the way forward

Abstract: Relatively speaking, the conservation of mammals, birds and other large terrestrial vertebrates is a simple task. The bulk of species are described, their ecologies are reasonably well known, the threats to their habitat or breeding systems are often documented, and the funding to implement recovery programmes readily available; e.g. mammals and birds are charismatic and the general public are fairly easily persuaded to identify with flagship species such as elephants, lions and snow leopards and financially support their conservation (Wilson, 1987; Clark & May, 2002). The major problems facing large vertebrate conservation are habitat loss/destruction and genetic bottlenecks. There is no shortage of volunteers to count, survey and protect these species; e.g. turtle watch, bird counts in Britain and North America, etc.

Where within a geographical range do species survive best? A matter of scale

Abstract: . 1 Opinions differ as to whether declining species are most likely to survive in central or peripheral parts of their distributions. The former pattern is likely to be driven by high extinction risks in peripheral areas; the latter by gradients of extinction risk. 2 At a continental scale of analysis, the declining butterfly Euphydryas aurinia survived best in southern and eastern countries within Europe. This was statistically associated with geographical variation in agricultural intensification. At this scale of analysis, there was a gradient of survival, caused by a gradient of agricultural intensification. 3 Within England and Wales, survival was greatest in population concentrations, or core areas; that is in 10-km grid squares that were surrounded by other 10-km grid squares that also contained populations of E. aurinia. In the English county of Dorset, populations were also most likely to be found in core areas; that is in habitat patches that were close to other populated habitat patches. 4 In this system, there is support for two patterns of decline. At a coarse scale, there is a geographical gradient of habitat degradation, associated with agricultural intensification. But within a region where decline has taken place, populations survive best in core areas, where aggregations of habitat support viable metapopulation dynamics. 5 Large-scale geographical patterns of decline towards the periphery (or other locations within) the distribution of a species do not negate the validity of conservation strategies based on core-margin population dynamic principles. Core areas within each country or region represent appropriate targets for conservation action.

A biogeographical study of the threatened ant Dinoponera lucida Emery (Hymenoptera: Formicidae: Ponerinae) using a cytogenetic approach

Abstract: . 1 Ants of the genus Dinoponera belong to a convergent group, in which there is no morphologically specialized caste of reproducing females and reproduction is by fertilized workers known as gamergates. Dinoponera lucida Emery, which is native to Brazilian Atlantic rain forest, is included on the official list of Brazilian fauna species threatened with extinction, due to habitat fragmentation, loss of their natural habitat and to peculiarities in their biology. 2 Karyotype variation was studied among D. lucida populations in the states of Bahia and Espirito Santo, Brazil. The cytogenetic study was carried out on brain ganglia and/or on male and/or female gonads. Banding techniques, such as sequential staining with DA/CMA3/DAPI fluorochromes and FISH, were also applied. 3 The diploid chromosome numbers ranged from 106 to 120. Variations in the karyotype were detected in the populations from Bahia, while in Espirito Santo the karyotypes were the same everywhere. Most of the chromosomes were small in size and acrocentric, except for a differentiated pair (AMt). This pair exhibited polymorphism in the different populations. 4 The karyotype variation detected in D. lucida suggested that the original population has previously been divided into two allopatric populations distributed in two different refugial areas of Atlantic rain forest in the early Quaternary. They probably developed in parallel and differentiated in karyotype composition. When the Atlantic rain forest regained its continuous distribution along with the Brazilian coast, the two groups came to occupy the continuous area of occurrence of the species that is seen today.

Choice of metrics for studying arthropod responses to habitat disturbance: one example from Gabon

Abstract: . 1 The choice of metrics comparing pristine and disturbed habitats may not be straightforward. We examined the results of a study in Gabon including 21 arthropod focal taxa representing 16 855 individuals separated into 1534 morphospecies. Replication included the understorey of 12 sites representing four stages of land use after logging (old and young forests, savanna and gardens), surveyed for 1 year using three sampling methods. 2 For all focal taxa, we calculated a suite of 13 metrics accounting for the intensity of faunal changes between habitats, namely: abundance; observed, rarefied and estimated species richness; proportion of rare species; additive diversity partitioning; evenness of assemblages; higher taxonomic composition; species turnover; ordination scores of multivariate analyses; nestedness; proportion of site-specific species and ratios of functional guilds. 3 Most metrics showed large differences between forests and non-forest habitats, but were not equally discriminating for particular taxa. Despite higher taxonomic groups being present in most habitats, many insect species were site or habitat specific. There was little evidence that the disturbance gradient represented a series of impoverished habitats derived from older forests. Rather, entire suites of species were being replaced as habitats were modified. 4 Metrics based on species identity had a high sensitivity to disturbance, whereas measurements describing community structure were less discriminating in this regard. We recommend using metrics based on abundance, estimated species richness, species turnover estimated by multivariate analyses and guild structure, to avoid misleading interpretations that may result from comparisons of species richness alone.

What determines whether a species of insect is described? Evidence from a study of tropical forest beetles

Abstract: The rainforest canopy has been called 'the last biological frontier', and if this is true, there should be more undescribed species in this stratum than the ground stratum. 2. Here, we test this and other hypotheses regarding traits of described and unde- scribed species by a sub-sample of 156 species into 96 described and 60 undescribed species from a beetle assemblage of 1473 species collected from the canopy and ground in an Australian lowland rainforest. 3. We show that described species are significantly more likely to be in the canopy, are more likely to be larger and, if they are large, are more likely to have been described earlier. 4. Undescribed species are just as likely to be found near the ground as in the canopy and are more likely to be smaller. 5. After the first year of sampling, 'new' described and undescribed species not previously encountered continued to appear in each of three further years of trapping. 6. These data show that the canopy fauna is in fact relatively 'well known', and that the undescribed species to be found in both strata are likely to be smaller than described species and are less likely to be plant feeders.

Effects of mobility on daily attraction to light traps: comparison between lepidopteran and coleopteran communities

Abstract: . 1 Light traps have been widely used for surveying insect community structure, but some biases are known to occur under certain meteorological conditions. 2 In addition to weather factors, we raise the novel hypothesis that if the daily movement distance of focal insects is shorter than the effective range of the light trap, then the species richness and abundance of the daily captures will increase during the course of the night. 3 This study examined the daily attraction patterns of Lepidoptera and Coleoptera to light traps and the factors affecting the attraction of these communities. Light traps were run for three consecutive nights in each month from April to October 2001 in a cool-temperate forest in Japan. 4 The species richness and abundance of Coleoptera increased during trap nights, whereas lepidopteran captures remained constant. Meteorological factors influenced the capture of both communities throughout the sampling season, but the daily increment in Coleoptera was not explained by the daily trends in weather conditions. 5 We argue that the daily augmentation of Coleoptera capture rate results from the daily movement distance of Coleoptera being generally shorter than the effective and perceivable range of the light traps. These results suggest that consideration of the typical daily movement of a focal taxon is required when conducting biological monitoring using light trap sampling.

Spatial distribution of rare species in lotic habitats

Abstract: . 1 Species rarity is a common phenomenon in the biological world. Although rare species have always interested biologists, the meaning of ‘rare’ has not always been clear with the definition of rarity often arbitrary. 2 In the current study, we investigate rarity in stream ecosystems using black flies (Diptera: Simuliidae). We defined rare species a priori as those species found ≤ 10% of stream sites examined (n = 111 streams for ‘summer collections’; n = 88 collection for ‘spring’ collections). Hence, we are exploring only one axis of rarity, restricted range. 3 We first consider the distribution of each rare species separately to determine if the mean (euclidian) distance among streams (habitats) for each rare species differs from a random model. We next took a collective approach by pooling all rare species to determine the influence of stream conditions, niche breadth, and distance among habitats on rarity. 4 Even within this biologically uniform group of flies, dispersal, range limits, and stream conditions all might play a role in rarity, and the importance of each of these factors appear to vary among species. Rather than looking for broad causes of rarity, future studies might be more fruitful if they looked at species-specific causes.

Parasitism of the beech leaf-miner weevil in a woodland: patch size, edge effects and parasitoid species identity

Abstract: 1. Deciduous woodlands are a key habitat for the diversity of invertebrates within the primarily agricultural landscape of lowland Scotland. Little is known, however, of the contribution that within site heterogeneity plays in maintaining invertebrate diversity within these habitats. We consider how habitat heterogeneity affects the beech leaf-mining weevil Rhynchaenus fagi L. (Curculionidae, Coleoptera) and its associated polyphagous parasitoids. 2. This was done by investigating host density and parasitism rates of the weevil as it fed on 88 beech trees (Fagus sylvatica L. (Fagaceae)) occurring in patches within a birch woodland. We aimed to assess how patch site, isolation and patch quality influenced parasitism rates and parasitoid diversity. 3. Herbivore leaf-mine abundance was greatest where beech trees were located on the edge. Parasitism rates were also affected by the location of the host insect at the woodland edge and interior. Depending on parasitoid species identity, parasitism rates showed independent, direct, and inverse responses to the density of leaf-mines. Parasitism rates showed direct and inverse responses to the patch sizes of beech trees, while overall parasitoid diversity was negatively correlated with patch size. 4. Heterogeneity in the location of the beech trees within this birch woodland plays a key role in determining local patterns of parasitism rates and parasitoid diversity. It is suggested that within site variation in the area of high quality resource patches, represented by the beech trees, was key to structuring these parasitoid communities. Niche separation was promoted by individual species capacity to locate host insects in this spatially complex habitat.

Numerical abundance of invasive ants and monopolisation of exudate-producing resources - a chicken and egg situation

Abstract: Invasive ants commonly reach abnormally high abundances and have severe impacts on the ecosystems they invade. Current invasion theory recognises that not only negative interactions, such as natural enemy release, but positive interactions, such as facilitation, are important in causing this increased abundance. 2. For invasive ants, facilitation can occur through mutualism with exudate-producing plants and insects. To obtain such partnerships, however, invaders must first displace native ants, whose communities are highly structured around such resources. 3. By manipulating the abundance of an invasive ant relative to a native, we show that a minimum threshold abundance exists for invasive ants to monopolise exudate-producing resources. In addition, we show that behavioural dominance is context dependent and varies with spatial location and numerical abundance. 4. Thus, we suggest a 'facilitation-threshold' hypothesis of ant invasion, whereby a minimum abundance of invasive ants is required before facilitation and behavioural dominance can drive abundance rapidly upwards through positive feedback.

Short‐term temporal variability in the abundance of tropical dung beetles

Abstract: . 1 Dung beetles are increasingly being used as a focal taxon in biodiversity and conservation studies. One of the alleged advantages of these insects is that sampling conducted in a few days can yield accurate data. 2 Dung beetles were collected twice, within a week, in a tropical dry forest in Mexico. The abundance of one species, Onthophagus landolti, increased 16 times in one of the habitats, over a period of a few days. Consequently, conclusions regarding differences between both habitats differed greatly depending on which sampling period was considered. 3 Short-term temporal variability in the abundance of dung beetles, particularly if spatially asymmetric, must carefully be considered when designing sampling protocols for this group of insects in dry tropical forests.

Longitudinal patterns of benthic invertebrates along a stream in the temperate forest in Japan: in relation to humans and tributaries

Abstract: . 1 The relationship between benthic invertebrate assemblage composition and surrounding land use has been examined in various ways, but most studies are undertaken at a coarse scale, or they compare obviously different landscapes. In Japan, these obvious differences in landscape are rare, and humans reside even in remote montane areas. 2 In order to clarify the influence of human residence on benthic invertebrate assemblages, seasonal and site differences among benthic samples collected from a 15-km stretch of Kuroson Stream and their relation with riparian land use were examined. 3 The number of individuals and genera differed significantly both spatially and temporally. Multivariate assemblage structure also differed significantly across space and time along the stream. 4 Increase of residential areas affected the in-stream benthic invertebrate assemblage. Site differences along the stream and the effect of human residence were not masked by the potentially homogenizing influence of tributary streams. 5 The composition of surrounding vegetation was the most important factor influencing benthic community structure. The presence or absence of human residential areas and seasonal change were also important variables. 6 Benthic invertebrates may be carried and migrate to main streams from tributaries; however, this phenomenon was not observed. Assemblages of benthic invertebrates that inhabit a particular site do not change and are considered to vary seasonally across a certain range.

Effects of isolation on the colonisation of restored habitat patches by forest‐dependent arthropods of soil and litter

Abstract: A novel experimental approach was taken to investigate the effects of dis- tance from rainforest remnants on the recolonisation patterns of ants and other soil and litter arthropods in 'restored' habitat patches within a pasture matrix. 2. Experimental habitat patches were created by adding a thick mulch of sterilised woodchips and leaves, and simulating shade using shadecloth, to create conditions similar to those that occur during rainforest restoration. These patches were deployed at five experimental sites in the Maleny plateau of subtropical eastern Australia. Artificial habitat patches were located at varying distances from a rainforest edge at each site, as well as within the rainforest. The experiment also included a test for efficacy of inoculation, which involved translocation of a small quantity of litter (containing live arthropods) from rainforest habitat to isolated habitat patches. 3. The results showed that, after 9 months, there was little colonisation by rainforest- dependent taxa in any of the experimental plots beyond those closely adjacent to forest patches. Inoculation was unsuccessful in increasing the extent of arthropod establishment. 4. A number of explanations that potentially account for the observed results are sug- gested. An experimental approach provides an opportunity to test explicitly for factors considered important for the development of biota in restored habitat patches. There are, however, unavoidable limitations associated with the design of experiments that simulate small-scale analogues of restoration treatments. Avoiding these limitations may require controlled and replicated efforts in experimental restoration over larger areas, based on collaborations between researchers and practitioners.

Distribution of burnet moths (Zygaena spp.) in relation to larval and adult resources on two spatial scales

Abstract: . 1 Metapopulation theory predicts habitat patch area and isolation to be the main factors affecting the distribution of species dependent of patchily distributed habitats, but the need for multiple resources, which might be spatially separated, is often ignored. 2 Here, I studied the effect of host plant and nectar flower distributions on the spatial distribution of pupae and adults of two species of burnet moths (Zygaena filipendulae and Zygaena lonicerae), on two spatial scales. 3 At the landscape scale (10 × 12 km), moths were patchily distributed, but there was no effect of patch isolation on the occurrence of any of the species. On the local scale (2 × 2 km), I expected to find additive effects of the local abundances of larval and adult resources and their abundances in the surrounding areas, but instead, moth abundance decreased with increasing resource connectivity. I interpret this as an aggregation effect, such that at low resource abundances in the area, moths tend to aggregate in patches with higher flower densities. 4 My results also supported the hypothesis that the spatial distribution of individuals at one life stage is restricted by the requirement of other life stages, because the abundance of pupae of both species were associated with floral resources and abundance of imagos was related to larval resources. 5 I conclude that in studies aiming at understanding the relative importance of local and regional factors for species distributions, it is important to account for the habitat requirements of all life stages.

Arthropod diversity sheltered in Thaumetopoea pityocampa (Lepidoptera: Notodontidae) larval nests

Abstract: In pine ecosystems, the role of the larval nests of the Mediterranean defoliator Thaumetopoea pityocampa as shelter of other arthropods, was studied for the first time. In Portugal, Pinus stands which differed in understorey plant diversity and level of attack by T. pityocampa were compared. 2. The arthropod fauna found sheltering inside the nests consisted of 60 species, representing 12 foraging types. Both arthropod richness and abundance were positively correlated with nest size, expressed as larval biomass. Arthropod richness was further positively correlated with understorey plant diversity, while no correlation was detected between arthropod richness and nest density. 3. Spiders accounted for up to 50% of the species richness, while 80% of the individuals collected were either juveniles, or females with brood, implying that T. pityocampa nests are used for overwintering and brood care. Seventy-six per cent of the Araneae were nocturnal ground foragers and specialised cryptic hunters, demonstrating the occurrence of indirect interactions among species belonging to different communities, namely ground vegetation layers and forest pine coppice. 4. It was concluded that, in Mediterranean pine ecosystems, T. pityocampa nests (i) create habitat diversification and contribute to improve overwintering survival of a wide range of arthropod species; (ii) play a functional role in the food web of pine ecosystems, by promoting indirectly mediated interactions among species from different communi- ties; and (iii) do not contribute to create habitat for symtopic phytophagous arthropods, since contrary to literature references for different types of shelters, 98% of the associ- ated species belonged to foraging types other than T. pityocampa.

A randomisation program to compare species-richness values

Abstract: . 1 Comparisons of biodiversity estimates among sites or through time are hampered by a focus on using mean and variance estimates for diversity measures. These estimators depend on both sampling effort and on the abundances of organisms in communities, which makes comparison of communities possible only through the use of rarefaction curves that reduce all samples to the lowest sample size. However, comparing species richness among communities does not demand absolute estimates of species richness and statistical tests of similarity among communities are potentially more straightforward. 2 This paper presents a program that uses randomisation methods to robustly test for differences in species richness among samples. Simulated data are used to show that the analysis has acceptable type I error rates and sufficient power to detect violations of the null hypothesis. An analysis of published bee data collected in 4 years shows how both sample size and hierarchical structure in sample type are incorporated into the analysis. 3 The randomisation program is shown to be very robust to the presence of a dominant species, many rare species, and decreased sample size, giving quantitatively similar conclusions under all conditions. This method of testing for differences in biodiversity provides an important tool for researchers working on questions in community ecology and conservation biology.

Phylogeography and conservation genetics of Californian coastal terrestrial communities: a comparative study using three beetles

Abstract: . 1 The coastal beach and dune environments of California host a diverse fauna of specialist arthropods, but are heavily and increasingly impacted by human activities. Little phylogeographical work has examined arthropods in these habitats, despite the importance of arthropods to community health. 2 We analysed the COI mitochondrial gene for approximately 80 individuals from nine dune systems in central and southern California for each of three coastal beetle species, Coelus ciliatus (Tenebrionidae), Hypocaccus lucidulus (Histeridae), and Cercyon fimbriatus (Hydrophilidae), examining overall phylogeographical patterns, inter-population connectedness, and concordance in these among species. 3 All species exhibited significant intra-specific diversity, with Co. ciliatus exhibiting both the lowest overall diversity and the strongest geographical structure. Cercyon fimbriatus was at the other extreme, exhibiting high diversity and essentially no geographical structure. None showed strong concordance with phylogeographical breaks common in either terrestrial or marine organisms, suggesting that coastal specialists may occupy their own unique realm. 4 Few populations of any species are monophyletic, but FST values for Co. ciliatus and H. lucidulus indicated moderately restricted gene flow; populations of Ce. fimbriatus appear panmictic. 5 Our results suggest that coastal beetles may be relatively good colonists, and likely to repopulate appropriate areas where management permits habitat to return to natural conditions.

Insect Conservation and Diversity– a new journal for the Royal Entomological Society

Abstract: Insect Conservation and Diversitya new journal for the Royal Entomological Society SIMON R. LEATHER, YVES BASSET and BRADFORD A. H AW KINS ' Division of Biology, Imperial College London, Silwood Park Campus, Ascot, UK ^Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Ancon, Panama City, Panama 'Department of Ecology & Evolutionary Biology, University of California, Irvine, CA, USA

A habitat suitability model for the narrow-headed ant, Formica exsecta, evaluated against independent data

Abstract: . 1 Predictive models are frequently used to assist forecasts of species’ distributions. For rare species, this approach can provide insights into habitat utilisation and potential habitat suitability that can assist conservation action. However the technique has seldom been used for invertebrates. 2 A habitat suitability model was constructed for the rare ant, Formica exsecta, at Glenmore, a pinewood site in Scotland that contains a significant proportion of the UK population of this species. A range of botanical and environmental variables were surveyed within cells in a grid structure. The model successfully re-classified 87% of cells according to the presence/absence of ant nests. When subject to a jackknife procedure, 70% of cells were successfully re-classified and the median predicted probability of presence in occupied cells was significantly greater than in unoccupied cells. 3 The model was further evaluated against three independent datasets with rates for successful predictions of 70%, 62.5% and 25%. The performance declined with increased distance from the area from which calibration data were collected. 4 We conclude that caution is required when a model is validated purely by reference to the data from which it was constructed and not against independent data. However, the process can provide useful insights into habitat suitability for rare invertebrates that can assist rapid assessment of potential ranges for conservation measures such as restoration of populations.

Quantification of termite attack on lying dead wood by a line intersection method in the Kabili‐Sepilok Forest Reserve, Sabah, Malaysia

Abstract: A line intersection method was used to estimate abundance (technically linear abundance: m1 m−2), biovolume (m3 ha−1) and size class distribution (defined by diameter) of lying dead wood in tropical forest. Additional semi-quantitative protocols assessed decay state (4 classes), termite attack (5 classes) and live termite occupancy (3 classes). Three forest types (kerangas, alluvial and sandstone) were sampled in the Kabili-Sepilok Forest Reserve of Eastern Sabah, using plots of 30 A— 30 m. Approximately 50 man-hours were required per site, at a replication of three plots per site and three well-separated sites per forest type. Mean biovolume of lying dead wood exceeded 8 A— 103 m3 ha−1 in kerangas (= heath) forest, with lower values in other types. Large items (> 19 cm diameter) were less than 10% of total abundance, but represented the largest biovolume, exceeding (alluvial) or equalling (kerangas) the total biovolumes of smaller categories combined. Most items (not less than 75%) were present as small wood (< 10 cm diameter). Items in the highest decay class had the highest biovolume. Termite attack was greater in the kerangas, where nearly 90% of items showed evidence of consumption, compared with 58% in the alluvial and 40% in the sandstone forests. Over 40% of items in the kerangas contained live termites compared with 25% in the alluvial and 15% in the sandstone. Items in the highest attack class (= almost total internal destruction) represented about one-half of the total biovolume available in the alluvial and kerangas forest types, and about one-third in the sandstone.