Springtails in space

The relative influence of environmental conditions, biotic interactions and dispersal limitation for community structure and diversity patterns is a reoccurring theme in community ecology. In studies of soil fauna communities, small-scale horizontal and vertical variations in environmental variables and biotic interactions have often been disregarded, despite these being key factors to understanding the diversity of soil fauna communities. In this thesis I examined the spatial distribution patterns of springtail (Collembola) species and communities in three different ecosystems: a salt marsh, mature pine forests and a high Arctic tundra meadow. The different systems consisted of a, to the human eye, homogeneous habitat. Still, they had different regimes and small-scale heterogeneity in environmental variables. In the three first studies the focus was on species and trait composition and diversity, at scales from 10 cm to 300 km. In the fourth paper I question the use of species-level analyses of distribution patterns, as different age classes within a species might be structured by different factors. I found that when habitat conditions were kept as similar as possible, the pine forest Collembola communities had similar functional diversity, although there was a high species turnover both between samples within study sites and between sites. The functional similarity between samples was lower in the salt marsh habitat, a habitat characterized by frequent inundation events. The small-scale variation in species and trait composition was best explained by spatial variables in the stable mature pine forest floor, while in the dynamic salt marsh environmental variation was most important. Coexisting species showed a higher difference in traits than expected in the pine forest, while coexisting species were similar in traits in the salt marsh. This indicates that species interactions can have a large impact on the community composition of springtails at small spatial scales. Small-scale niche partitioning may be one explanation for the high local diversity observed in many soil communities. I found that incorporating species-specific trait information in studies greatly helps our understanding of the mechanisms structuring communities, despite the finding that in some species of collembolans different age classes may use space differently. To improve our understanding of Collembola communities both these factors should be considered in future studies

Substrate specificity among Diptera in decaying bioenergy wood: can they be conserved by the same measures as are currently applied to beetles?

Although threatened by forestry, our knowledge concerning saproxylic insects is strongly biased towards well-known orders, mainly beetles (Coleoptera). The beetles have, therefore, formed the basis on which conservation measures of other groups have been formulated. Despite being more species-rich, the Diptera have been rather neglected. Moreover, our limited knowledge of the Diptera suggests that their demands on the dead wood substrate differ markedly from that of coleopterans. We tested if this is true by comparing the substrate requirements of dipteran and coleopteran species by analysing the affinities of species assemblages for logging residues differing in age, size, and tree species. Insects were reared out from the same samples of bioenergy wood from clear-cuts in Sweden. 15 species of Brachyceran flies were compared with 56 species of Coleoptera. We found the average level of specialisation to be similar between the two groups, but the dipterans had (contrary to the expectations) a higher proportion of specialists. Affinities for differently aged wood were similar. More dipterans than beetles were associated with the coarsest wood (diameter 9 cm-15 cm). More dipterans than beetles tended to be associated with aspen (Populus tremula), while Coleoptera tended to be more associated than Diptera with oak (Quercus) and spruce (Picea abies). We conclude that most recommendations for conserving the saproxylic beetle fauna also seem to benefit dipterans, but that the dipterans might be even more sensitive to which qualities of the wood that is preserved. The high conservation value of aspen is already recognised and our results for dipterans strengthen this. The high incidence of many dipteran species in logging residues suggests that many dipterans use sun-exposed environments

Traits or species – space or environment

How communities are structured and the processes shaping species composition are among the basic questions in ecology. Knowledge about these processes is essential to predict changes in community composition in response to changes in for example climate or land use practices. Soil communities are considered to be both remarkably species-rich and to have many generalist species with seemingly similar niche requirements. Soil fauna composition shows a large variation even at small spatial scales and both local environment and spatial configuration of habitats are regarded as important forces shaping the community composition. In this thesis, I examine the factors influencing small-scale community composition of springtails (Collembola) in two habitats, a variable and dynamic salt marsh and a more stable mature pine forest. The functional traits of species determine both their responses to the environment and their effects on ecosystem processes. The current knowledge on environment - species - traits relationship is limited in spite of its potential importance for ecosystem function. I show that by combining perspectives from two closely linked theoretical frameworks – metacommunity ecology and community assembly theory – we get a better understanding of the important ecological factors operating in this system. I found that the factors influencing community composition was context dependent, but in a predictable way. In the environmentally variable habitat, salt marsh, with spatial and temporal heterogeneity, there was evidence of strong environmental filtering. Small-scale topography was the strongest predictor of community composition, likely due to disturbances restricting where habitat-generalists can persist. In contrast, in the more stable habitat, mature pine forest, environmental filtering appeared weaker and biotic interactions seemed to have a stronger impact. Coexisting species were more similar in traits related to resource utilisation and sensory ability than expected, and variation in species composition was explained mainly by spatial factors like the distance between samples, i.e. each local community seemed to depend on the composition of the surrounding communities

Operationalisation of ecological compensation - Obstacles and ways forward

Ecological compensation (EC) has been proposed as an important tool for stopping the loss of biodiversity and natural values. However, there are few studies on its actual operationalisation and there is high uncertainty about how it should be designed and implemented to be an effective way of performing nature conservation. In this study we focus on ecological compensation in Sweden, a country where it is in the process of being implemented more broadly. Using interviews and a workshop we investigate how the work with the implementation is carried out and what challenges exist. The results show that implementation of EC is at an early stage of development and there are many practical obstacles, linked to both legislation and routines in the planning processes. There is a lack of holistic perspective and large-scale thinking, a quite strong focus on a small number of individual species, and an overall attitude that anything is better than nothing, all of which can have negative consequences for biodiversity conservation overall. Based on the results we discuss the need for better integration of EC into the entire decision-making process and for a holistic approach to preservation of biodiversity and ecosystem services, by increasing the focus on landscape perspective and considering delays in compensation outcomes. There is also a need for a national level standard for EC, making good and worse examples of compensation measures available and systematic monitoring of EC projects. Finally, a spatially explicit database to document all EC areas should be introduced both to ensure consistency in protection from future development plans and to enable long-term monitoring of EC outcomes

Small-scale Collembola community composition in a pine forest soil - Overdispersion in functional traits indicates the importance of species interactions

Soil communities are considered to be remarkably species-rich and to have many generalist species with seemingly similar niche requirements. The composition of soil fauna communities is often highly variable even at the plot scale, and both the environment and the spatial configuration of microhabitats are regarded as important forces shaping the structure of local communities. However, to what extent these forces are important in different ecosystems is not clear. We examined the relative roles of environmental (abiotic), vegetation (biotic) and spatial variables (using Moran's eigenvector maps, MEM) for the small-scale variation in springtail (Collembola) communities in a 100 m(2) area of the forest floor of a mature Scots pine forest in central Sweden, with small variation in important environmental variables.We found that most of the small-scale variation in community composition could be explained by spatial variables, either alone or jointly with the environmental variables. Spatial variability in community composition, in turn, could be related to shifts in functional traits of the component species. Within local communities (samples), species showed a higher diversity than expected by chance in almost all examined traits, indicating that differences in resource and micro-habitat utilisation enable Collembola species to coexist. Competition between species is therefore likely to be important for structuring Collembola communities at this spatial scale. The results indicate that the spatial scale of study and heterogeneity of environmental factors influence soil fauna community assembly processes through effects on the relative importance of environmental filtering compared to filtering by limiting similarity or competitive exclusion. (C) 2016 The Authors. Published by Elsevier Ltd

Translocation of a sand-associated blister beetle (Apalus bimaculatus) due to urban development in Uppsala, Sweden

The blister beetle (Apalus bimaculatus, Coleoptera: Meloidae) is a beetle managed for conservation in Sweden. The species inhabits at-risk ephemeral and patchily distributed sandy habitats and are dependent on stable colonies of the bee species (Colletes cunicularius) on which it parasitizes. The beetle is not considered threatened at a global or European level. It has previously been categorized as Vulnerable (VU, 2000) and near threatened (NT, 2005 & 2010) in the Swedish National List, but are now considered as Least Concern (LC, 2015). The change in categorization is due to that more populations have been found, which is believed to be an effect of overlooked populations in the past. The species is still considered as declining in the country, due to a general decrease in area of suitable habitat e.g. from sandpits becoming overgrown after excavation has ceased, and when sand dunes and other sandy areas are used for human development. The beetle population in this project has until now inhabited a sandy area between pine-dominated forest and areas used for human activities. The site is in Uppsala, Sweden, and it is located in a part of the city previously little used for human development but where major building work is planned and ongoing

Protected area designation and management in a world of climate change: A review of recommendations

Climate change is challenging conservation strategies for protected areas. To summarise current guidance, we systematically compiled recommendations from reviews of scientific literature (74 reviews fitting inclusion criteria) about how to adapt conservation strategies in the face of climate change. We focussed on strategies for designation and management of protected areas in terrestrial landscapes, in boreal and temperate regions. Most recommendations belonged to one of five dominating categories: (i) Ensure sufficient connectivity; (ii) Protect climate refugia; (iii) Protect a few large rather than many small areas; (iv) Protect areas predicted to become important for biodiversity in the future; and (v) Complement permanently protected areas with temporary protection. The uncertainties and risks caused by climate change imply that additional conservation efforts are necessary to reach conservation goals. To protect biodiversity in the future, traditional biodiversity conservation strategies should be combined with strategies purposely developed in response to a warming climate

Globally invariant metabolism but density-diversity mismatch in springtails.

Soil life supports the functioning and biodiversity of terrestrial ecosystems. Springtails (Collembola) are among the most abundant soil arthropods regulating soil fertility and flow of energy through above- and belowground food webs. However, the global distribution of springtail diversity and density, and how these relate to energy fluxes remains unknown. Here, using a global dataset representing 2470 sites, we estimate the total soil springtail biomass at 27.5 megatons carbon, which is threefold higher than wild terrestrial vertebrates, and record peak densities up to 2 million individuals per square meter in the tundra. Despite a 20-fold biomass difference between the tundra and the tropics, springtail energy use (community metabolism) remains similar across the latitudinal gradient, owing to the changes in temperature with latitude. Neither springtail density nor community metabolism is predicted by local species richness, which is high in the tropics, but comparably high in some temperate forests and even tundra. Changes in springtail activity may emerge from latitudinal gradients in temperature, predation and resource limitation in soil communities. Contrasting relationships of biomass, diversity and activity of springtail communities with temperature suggest that climate warming will alter fundamental soil biodiversity metrics in different directions, potentially restructuring terrestrial food webs and affecting soil functioning

Global fine-resolution data on springtail abundance and community structure

Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated ~32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data.</p

Global fine-resolution data on springtail abundance and community structure

Springtails (Collembola) inhabit soils from the Arctic to the Antarctic and comprise an estimated similar to 32% of all terrestrial arthropods on Earth. Here, we present a global, spatially-explicit database on springtail communities that includes 249,912 occurrences from 44,999 samples and 2,990 sites. These data are mainly raw sample-level records at the species level collected predominantly from private archives of the authors that were quality-controlled and taxonomically-standardised. Despite covering all continents, most of the sample-level data come from the European continent (82.5% of all samples) and represent four habitats: woodlands (57.4%), grasslands (14.0%), agrosystems (13.7%) and scrublands (9.0%). We included sampling by soil layers, and across seasons and years, representing temporal and spatial within-site variation in springtail communities. We also provided data use and sharing guidelines and R code to facilitate the use of the database by other researchers. This data paper describes a static version of the database at the publication date, but the database will be further expanded to include underrepresented regions and linked with trait data