A diverse beetle assemblage from a newly discovered Cenozoic fossil site near Penrose, New South Wales, Australia

We explored how morphological traits can complement phylogenetic information to extend our predictions of the ecology of a diverse beetle assemblage. We analysed ten morphological traits from an assemblage of 239 species from 35 families, and identified three axes of morphological variation that were independent of body length: (1) relative robustness; (2) relative appendage length; and (3) relative abdomen length. The trait associations defining these axes of morphological variation did not change after adjusting for family-level phylogeny. We detected significant differences in morphological variation across the beetle assemblage according to diet and microhabitat use, and these patterns were only partially influenced by family membership. Further analysis within dominant families showed that species of Carabidae, Curculionidae, Scarabaeidae and Staphylinidae had greater body length in open versus tree litter microhabitat, and species of Carabidae and Curculionidae had greater relative robustness, but shorter relative appendage length, in open versus tree litter microhabitat. Although it is clear that family-level phylogeny and morphology share some explanatory power for predicting the diet and microhabitat use by beetles, we demonstrate that body length, robustness and appendage length are correlated significantly with microhabitat use when comparing members of the same family. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102, 301–310.

Oak woodlands belong to the natural vegetation in most Mediterranean regions but have suffered from a long history of woodland devastation and overgrazing. The remaining woodlands have been managed in different ways, and we expected this to have effects on the fauna associated with trees. We investigated three different sites in the Eastern Mediterranean with flightinterception traps to analyse the impact of woodland management on dead wood and tree structures and the relevance for saproxylic beetle assemblages. Our results show significant differences in trunk diameter, stem density and dead wood diversity between the three sites. Old oaks in semiopen woodland are characterised by diverse stages of dead wood and harboured most saproxylic species (74 species out of a total of 98) and most individuals. With regard to rarefied species richness, we found that coppice woodland with a high stem density and medium-sized trees has the most diverse beetle assemblage (19.7 species per 100 individuals). Species richness was in general strongly associated with the diameter of the oaks, but, surprisingly, was also of the same level as species numbers reported from studies in Central Europe. The large number of singletons, which made up 40 % of the entire sample, may indicate a considerable number of species that were not trapped. We discuss the impact of different management options on tree shape and woodland structure, issues which are also important for the saproxylic beetle assemblage associated with Mediterranean oaks. We conclude that oak woodlands in the Middle East – and especially those woodlands that have been used and managed in a sustainable way – represent a valuable resource for insect diversity.

Altered abiotic conditions resulting from human-induced climate change are already driving changes in the spatial and temporal distributions of many organisms. For insects, how species are distributed across elevations is relatively well known, but data on their seasonality at different elevations are lacking. Here we show seasonal variation in beetle abundance and species richness along two spatially-distinct elevational transects (350–1000 m and 100–1000 m asl) in the rainforests of northern Australia. Temperature was the best predictor of temporal abundance and species richness patterns, while rainfall had little influence. Elevation had little effect on seasonal changes in abundance or diversity. Adults of most beetle species exhibited long season-lengths (>6 months of the year) with distinct peaks in abundance during the summer wet-season. We found evidence of phenotypic variation among the more widespread species, with seasonal peaks in abundance often not coinciding across elevations or transects. Due to the wide elevational range of most species, and the lack of consistency in the seasonality of wide-spread individual species, we suggest that many beetles inhabiting the low to mid-elevation mountains in the Wet Tropics, and potentially other tropical rainforests, are not as vulnerable to extinction due to climate change as many other organisms.

ABSTRACTOne of the least understood aspects of insect diversity in tropical rain forests is the temporal structuring, or seasonality, of communities. We collected 29,986 beetles of 1473 species over a 4‐yr period (45 monthly samples), with the aim to document the temporal dynamics of a trophically diverse beetle assemblage from lowland tropical rain forest at Cape Tribulation, Australia. Malaise and flight interception traps were used to sample adult beetles at five locations at both ground and canopy levels. Beetles were caught throughout the year, but individual species were patchy in their temporal distribution, with the 124 more abundant species on average being present only 56 percent of the time. Climatic variables (precipitation, temperature, and solar radiation) were poorly correlated with adult beetle abundance, possibly because: (1) seasonality of total beetle abundance was slight; (2) the peak activity period (September–November) did not correspond to any climatic maxima or minima; or (3) responses were nonlinear owing to the existence of thresholds or developmental time‐lags. Our results do not concur with the majority of tropical insect seasonality studies suggesting a wet season peak of insect activity, perhaps because there is no uniform pattern of insect seasonally for the humid tropics. Herbivores showed low seasonality and individual species’ peaks were less temporally aggregated compared to nonherbivores. Canopy‐caught and larger beetles (> 5 mm) showed greater seasonality and peaked later in the year compared to smaller or ground‐caught beetles. Thus seasonality of adult beetles varied according to the traits of feeding ecology, body size, and habitat strata.

The endemic-rich Afromontane grassland on the Drakensberg in Southern Africa is subjected to intensive afforestation. We describe fine-scale variation in the assemblages of the Coleoptera within the context of a grassland fragmentation experiment. The study site supports a speciose coleopteran fauna of >131 morphospecies. Variation in beetle assemblage corresponds to fine-scale variation within the plant community of which the 10 most dominant plant species are shared across all plant associations. Because these variants of the grassland community are localized, this suggests a high degree of endemicity for the grassland Coleoptera. The correlation between ordinations of beetle assemblages and those reflecting botanical composition is remarkable. Spatial autocorrelation analysis reveals that several species have geographically clumped distributions among sites. There was a correlation between, on the one hand, seasonal differences between beetle assemblages within each treatment (due to the fact that some insects are closely associated with particular plant assemblages), and, on the other hand, seasons in which correlations in beetle-habitat ordinations were high. However, within the context of the fragmentation experiment, the grassland fragments and control sites are statistically comparable because similar plant-beetle associations existed in both treatments. Thirteen beetle taxa are identified which collectively comprise an efficient tool for monitoring the effects of habitat fragmentation on the montane grassland.

Ground beetle (Carabidae) assemblages are speciose and frequently employed as indicators of ecosystem function. It is thus important to understand the factors that affect their spatial distributions so as to better interpret how ecosystem variation influences the structure of their assemblages. We evaluated how anthropogenic disturbances, habitat heterogeneity, and spatial autocorrelation (unmeasured spatially structured habitat variables and/or dispersal limitation) influence the distribution of carabids on a mature boreal forest landscape. We worked with a large sample of carabids from 194 sites from a near‐regular grid covering 70 km2. Data about forest floor cover, vegetation structure, soil drainage, and topography were associated with each site. We modelled the structure of carabid assemblages using these variables together with Moran’s eigenvector maps (MEM) as spatial constraints. Overall, our model explained about half of the variation in ground beetle assemblages. Forest floor cover, soil drainage, and vegetation structure were the principal factors useful for explaining carabid assemblages. The spatial patterns described by the MEMs for the ground beetle assemblages seem to result from spatial autocorrelation in soil drainage, floor cover, topography, and vegetation structure; however, this spatial autocorrelation independently and uniquely explained only 1.4% of the variation in assemblages. This was much less important than the explanatory power of the environmental variables considered; e.g. ground cover descriptors and vegetation structure by themselves accounted, respectively, for 12.1 and 4.5% of the variation in the carabid data. The spatial distribution of ground beetles in undisturbed forest was only mildly affected by surrounding anthropogenic disturbances, but clearly small patches were invaded by species characteristic of open habitat. We conclude that to help conserve ground beetle diversity at the landscape scale in boreal forests, mature forest patches should be large and connected to other patches and the surrounding forest.

Timber tree plantations are considered for rehabilitating forest biodiversity in the tropics, but knowledge on determinants of faunal diversity patterns in such human-modified forest landscapes is scarce. We quantified the composition of beetle assemblages on three native timber species (Anacardium excelsum, Cedrela odorata and Tabebuia rosea) planted on former pasture to assess effects of tree species identity, tree species diversity, and insecticide treatment on a speciose group of animals in tropical plantations. The beetle assemblage parameters ‘abundance’, ‘species richness’, ‘Chao1 estimated species richness’ and ‘Shannon diversity’ were significantly reduced by insecticide treatment for each tree species. Shannon diversity increased with stand diversification for T. rosea but not for A. excelsum and C. odorata. Species similarity was highest (lowest species turnover) between beetle assemblages on T. rosea, and it was lowest (highest species turnover) for assemblages on insecticide-treated trees of all timber species. Considering trophic guilds, herbivorous beetles dominated on all tree species and in all planting schemes. Herbivores were significantly more dominant on T. rosea and C. odorata than on A. excelsum, suggesting that tree species identity affects beetle guild structure on plantation trees. Insecticide-treated stands harbored less herbivores than untreated stands, but exhibited a high abundance of predator beetle species. Our study revealed that even young pasture-afforestations can host diverse beetle assemblages and thus contribute to biodiversity conservation in the tropics. The magnitude of this contribution, however, may strongly depend on management measures and on the selected tree species.

Background/Question/Methods. Ponds are among the most diverse and yet threatened components of freshwater biodiversity. The conservation of ponds would greatly benefit from the identification of surrogate taxa in preliminary assessments aimed at detecting ponds of potentially high biodiversity value. Vascular plants and water beetles have often been used in pond conservation assessments. To evaluate whether wetland plants are a suitable surrogate group to evaluate pond biodiversity, we used plant, beetle, and environmental data collected from 54 ponds located in two farmed regions in Ireland. Specifically, we aimed at assessing cross-taxon congruence between water beetles and plants; quantifying and comparing the capacity of vegetation data and environmental variables to predict beetle species composition; assessing and comparing the response of plant and beetle communities to environmental conditions. The predictive strength of vegetation data was evaluated at the levels of species and community type composition, and species diversity. To identify the best predictor data-set for beetle species composition, we used predictive co-correspondence analysis (Co-CA) and predictive canonical correspondence analysis (CCA-PLS). Congruence in species richness was calculated using simple regression analysis, while a generalized linear model was developed to quantify the effect of environmental variables on patterns of beetle and plant diversity. Results/Conclusions. The study ponds supported over 30% of the Irish water beetle fauna (76 species), with five species having some form of IUCN Red List Status in Ireland, and 67 wetland plant species, including a nationally rare one. Co-CA showed that plant species composition had a positive predictive accuracy, which was significantly higher compared to that of data at the plant community type level. Although environmental variables showed a higher predictive capacity compared to that of plant species composition, the difference was not significant. Explanatory CCA analyses showed that plants and beetles both responded to the same subset of environmental conditions, explaining ca.18% of the variation in both plant and beetle species composition. Regional differences, permanency, substratum, and grazing intensity affected the composition of both plant and beetle assemblages. The relationship between plant and beetle diversity was rather weak, reflecting the contribution of few plant species in supporting diverse beetle assemblages. These findings have important implications in conservation planning. First, the composition of wetland plants can be effectively used as a surrogate taxon in the identification of conservation-priority ponds. Second, conservation strategies aimed at maintaining and enhancing pond biodiversity should be based on considerations on the vegetation.

Abundant fossil beetles were obtained from the Lower Pleistocene Ookui Formation in Kitamimaki-mura, Kitasaku-gun, Nagano Prefecture, Central Japan. These fossils are composed of ground and aquatic beetles, such as Carabidae, Dytiscidae, Hydrophilidae, and Donaciinae of Chrysomelidae. Several fossils of ground beetles are identified with three interesting species, Hemicarabus maeander, Apotomopterus maacki, and Chlaenius gebleri. Among them, H. maeander is not distributed in Honshu where the fossil occurred, but can be found in Hokkaido, Chejudo, Sakhalin, N. E. China, Mongolia, East Siberia, and North America at the present time. The fossil finding indicates that the widely and continuous distributional range of this species seemed to become discontinuous, and extinct in Honshu after the Early Pleistocene. Thus, this species can be considered as a geographic relict species in Honshu during the Pleistocene. The paleoenvironment of the Upper member of the Ookui Formation based on beetle fossils seems that there were mainly low moor of reeds accompanied with areas of still water. These beetle assemblages, especially including H. maeander and C. gebleri, suggest presence of low moor which is similar to those found in Hokkaido during the Upper member of the Ookui Formation deposited.

Beetle fossils: Late Pleistocene of North America

Re-envisioning the structure of last glacial vegetation in New Zealand using beetle fossils

13 Studies in Australia and New Zealand

Insects are well recognised as being the major contributor to global biodiversity, and for their critical involvement in many biotic interactions. Most of the insect diversity is found in tropical rainforests. However, these forests are threatened by high rates of clearing and the subsequent fragmentation of remaining habitat. The effects on biota, particularly insects, are poorly understood as are the mechanisms mediating faunal changes. Reforestation could potentially alleviate some of the deleterious effects of forest loss and fragmentation. However, because reforestation is a relatively new endeavour, it is little known just how much insect biodiversity can be supported by reforestation and what factors influence insect colonisation. These issues were investigated in the Atherton Tablelands of north-eastern Australia, a landscape whose rainforest has been heavily cleared and fragmented over the last 80 years, but is also the focus of reforestation efforts. To quantify the effects of rainforest loss and fragmentation, pasture sites were compared with small rainforest fragments, and with the edges and interiors of large rainforest fragments (24 sites in total). Sites with replanted rainforest (planted with a high diversity of plants) were also included. These varied in their age (2-17 yrs) and their distance (0-4.5 km) from existing rainforest (24 sites in total). Another set of reforested sites was also studied but these differed in their planting style (number of plant species, spacing etc). This second set of sites was located in two regions: the Atherton Tablelands (50 sites), and in the subtropics of eastern Australia (54 sites). At each site, beetle assemblages were surveyed using methods that sample beetles near the ground (four ground-based flight interception traps in the first set of sites and ten pitfall traps in the second set of sites), and then the assemblages among site-types were compared. Over 32,000 beetles were caught and identified to the level of family, and of these, 15,206 were identified further to the level of species. Very few beetle species were present in pasture, suggesting that converting rainforest into pasture has a very strong negative effect on beetle diversity and species composition. Irrespective of rainforest fragment size, beetle species composition in drier rainforest habitats was different from that of moister rainforest. Beetle species composition also differed between small remnants and interior rainforest: drier-associated species were more abundant in small remnants, whereas wetter-associated species were more abundant in interiors. This pattern can be best attributed to a fragmentation effect mediated by differences in microclimate. With the exception of differences between rainforest and pasture, these results were generally not observed among beetle assemblages identified to coarser taxonomic groups (family, feeding guild, and body size). Among replanted rainforest, older sites and those adjacent to rainforest had a more rainforest-like beetle species composition. However, even the closer and older sites had a substantially lower abundance and richness of rainforest-associated beetles than did rainforest. Age effects were generally stronger than distance effects. Beetle assemblage similarity to rainforest was more strongly correlated with structural similarity to rainforest than with site age or distance from rainforest. Thus the use of revegetation techniques which lead to more rainforest-like structural conditions appears to be of over-riding importance in catalysing the rapid acquisition of rainforest beetle assemblages in the initial stages of restoration. Nevertheless, not all beetle species were equally affected by the factors tested. Large-bodied beetle species (>5 mm) were more strongly influenced by distance than small-bodied species (<5 mm), suggesting that small-bodied species are better dispersers, and thus are amongst the first to colonise new habitats. Spatial ubiquity in rainforest was not a good predictor of a species' dispersal ability. Interestingly, fewer of the broader groups (family, feeding guild, and body size) showed the response to distance evident at the species level although they showed differences between reforested sites differing in age, and between reforested and reference site-types. Therefore, these results and those from the fragmentation study suggest that information at the species level is more sensitive to environmental change than data identified to a coarser level of taxonomy or grouped according to feeding ecology or body size. For the pitfall-trapped beetles in the second reforested site network, beetle assemblages in all styles of reforestation were intermediate in species composition between pasture and rainforest. The similarity of beetle assemblages to intact rainforest increased with the age and structural complexity of reforested sites, although again structural complexity appeared to be of overriding importance. This study has shown that even small patches of rainforest and reforested areas can support diverse rainforest-dependent beetle assemblages. A range of factors influence the development of beetle assemblages in reforested sites although not all species are equally affected. However, even structurally complex reforested sites cannot provide a short- or medium-term substitute for the retention of intact rainforest.

The role of deterministic and stochastic mechanisms in community assembly is a key question in ecology, but little is known about their relative contribution in dung beetle assemblages. Moreover, in human modified landscapes these mechanisms are crucial to understand how biodiversity can be maintained in productive agroecosystems. We explored the assembly mechanisms driving dung beetle assemblages in forests and grazed grassland patches, and assessed the role of dung availability, soil hardness and moisture, elevation and land use heterogeneity as environmental predictors of functional diversity. To determine the underlying assembly mechanisms, we estimated functional diversity metrics (functional richness, evenness and divergence) and their departure from the predicted values by null models. We also used GLMs to assess the influence of environmental variables on functional diversity. In most cases, stochastic processes prevailed in structuring dung beetle assemblages and, consequently, environmental variables were not good predictors of dung beetle functional diversity. However, limiting similarity was found as a secondary mechanism with an effect on dung beetle assemblages in grasslands. Our results highlight the importance of stochastic processes that may reflect a metacommunity dynamic. Therefore, restoring landscape connectivity might be more important than habitat quality for the conservation of these functionally diverse beetle assemblages.

The appearance of spider (Araneae) and beetle (Coleoptera) assemblages found in nests of great reed warbler Acrocephalus arundinaceus was studied, firstly to investigate breeding success and the amount of precipitation as potential factors which might affect the abundance and species richness of both groups. In addition, we compared the diversity of spider and beetle assemblages between nests found in different reed habitats, and considered the position of nests (above water or dry ground). In this study we selected five different randomly chosen reed habitats: two mining ponds, two small canals and one large canal. Great Reed Warbler nests were collected either shortly after fledging, or after the clutch had failed. Altogether, 12 species of spider and 19 species of beetle were collected. In both groups there was no significant difference in abundance between successful, lost and cuckoo-parasitized nests; however, there was a significant difference in species richness between the three nest categories in spider assemblages, which was not the case in beetle assemblages. The amount of precipitation did not affect beetle or spider abundance; only the species richness of spiders showed significant growth. Furthermore, we found no significant relationship between vegetation cover and the species richness and abundance of spiders and beetles. The diversity of both groups differed significantly according to reed habitat: beetle assemblages were most diverse by the large canal and spiders at the mining ponds.