Ihmistoiminnan ja ennallistamisen vaikutukset soiden selkärangatonlajistoon

Negative anthropogenic disturbances (e.g., drainage and urbanization) are causing biotic homogenization through the replacement of specialist species with generalists. The identification and conservation of biodiversity hotspots within degraded (e.g., highly urbanized) landscapes, and ecological restoration (i.e., positive anthropogenic disturbance) have the potential to be important tools to counteract these negative effects. Mires are suitable targets for the investigation of these homogenization-reducing activities since they host many mire specialist species of, e.g. invertebrates. The main aim of this PhD thesis was to investigate the effects of negative anthropogenic disturbances [urbanization (Chapter I) and drainage for forestry (Chapters II-IV)] on the invertebrate communities of boreal mires and how effective efforts are to reverse these negative effects through ecological restoration [i.e. positive anthropogenic disturbance (Chapters II-IV)]. In addition, the purpose was to determine which environmental variables are key in supporting mire specialist invertebrate species and communities. Therefore, this thesis started by reviewing current knowledge on the responses of mire invertebrate species and communities to anthropogenic disturbances. The effects of urbanization were studied on spiders and carabid beetles (Chapter I), while the effects of drainage for forestry and subsequent restoration were investigated on five solitary invertebrate groups (Chapter II) and social insects, i.e. ants (Chapter III). Finally, a powerful Before-After Control-Impact (BACI) design was used to reveal the effects of drainage and restoration on butterflies (Chapter IV). Generally, both high levels of urbanization (Chapter I) and mire drainage for forestry (Chapters II-IV) had negative effects on mire specialist species (lower abundances) and invertebrate communities (homogenized and very different in structure from pristine mire communities). However, these detrimental effects can be reduced or even reversed through appropriate urban mire conservation and ecological restoration. Local habitat conditions were shown to be particularly important for the survival of specialist invertebrate species in urban mires (Chapter I) and for the successful recovery of restored mire invertebrates (Chapters II-IV). Individual mire specialist species responded negatively to environmental variables associated with deteriorated (i.e. drained or highly urbanized) mire conditions [number of high (> 3m) trees for carabid beetles, crane flies, micromoths (Chapter II), ants (Chapter III) and butterflies (Chapter IV)] and positively to pristine mire-associated variables [Sphagnum cover for carabid beetles and spiders (Chapters I-II), crane flies (Chapter II) and suggestively for ants (Chapter III); larval food plant cover and number of lower (1.5 - 3m) trees for butterflies (Chapter IV)]. The more specialized the mire species were, the more negatively they were affected by deteriorated-mire-associated variables and the more positively they responded to pristine-mire-associated variables. I conclude that the restoration actions taken (removing tall trees but leaving smaller trees, and raising the water table level) are appropriate in creating suitable habitat conditions for mire invertebrates, as both individual specialist species and communities showed positive responses already 1-3 years since restoration (Chapters II-IV). Finally, the appropriate restoration actions in well-prioritized locations as well as urban mire conservation should reverse the trend of biotic homogenization.Biologinen homogenisaatio eli samankaltaistuminen aiheuttaa usein erikoistuneiden spesialistilajien korvautumisen yleislajeilla, generalisteilla. Homogenisaatio on seurausta haitallisesta ihmistoiminnasta, kuten elinympäristöjen kuivattamisesta tai urbanisoitumisesta. Monimuotoisimpien elinympäristöjen tunnistaminen, suojelu ja ennallistaminen ovat keinoja torjua näitä haitallisia muutoksia. Soiden erikoistunut selkärangatonlajisto tarjoaa mahdollisuuden tutkia kuinka lajiston yksipuolistumista voitaisiin vähentää. Tämän tutkimuksen tarkoituksena oli selvittää miten ympäristölle haitallinen ihmistoiminta kuten urbanisaatio (Artikkeli I) ja metsänojitus (Artikkelit II-IV) vaikuttavat boreaalisen vyöhykkeen soiden selkärangatonlajiston rakenteeseen ja kuinka havaittuja negatiivisia muutoksia lajistossa on onnistuttu torjumaan tai vähentämään aktiivisilla ennallistamistoimilla. Tutkimuksessa pyrittiin myös tunnistamaan, mitkä ympäristötekijät ovat soihin erikoistuneen lajiston kannalta keskeisimpiä ja miten suolajisto reagoi haitalliseen ihmistoimintaan. Kaupungistumisen vaikutuksia selkärangatonyhteisöihin tutkittiin hämähäkeillä ja maakiitäjäisillä (Artikkeli I). Metsänojituksen ja ennallistamisen vaikutuksia lajiyhteisöihin tutkittiin viidellä eri selkärangatonryhmällä (Artikkeli II) ja sosiaalisilla hyönteisillä (muurahaisilla) (Artikkeli III). Artikkelissa neljä metsänojituksen ja ennallistamisen vaikutuksia perhosten lajistorakenteeseen päästiin tutkimaan ennen ennallistamistoimia ja sen jälkeen. Sekä kaupungistuminen (Artikkeli I) että metsänojitus (Artikkelit II-IV) johtivat suoympäristöön erikoistuneiden selkärangattomien taantumiseen ja lajiston yksipuolistumiseen ja muuttumiseen hyvin erilaiseksi kuin luonnontilaisilla soilla. Näitä kielteisiä muutoksia on kuitenkin mahdollista lieventää tai jopa kokonaan välttää soiden suojelulla ja ennallistamisella. Paikalliselin ympäristön piirteillä on erittäin suuri merkitys erikoistuneen selkärangatonlajiston menestykseen sekä urbaaneilla alueilla olevilla soilla (Artikkeli I) että ojitetuilla ja ennallistetuilla soilla (Artikkelit II-IV). Suoympäristöön erikoistunut lajisto taantui ihmistoiminnan lisääntyessä soilla. Ympäristömuuttujista yli 3 metristen puiden runsastumisen havaittiin vähentävän maakiitäjäisten, vaaksiaisten, mikroperhosten, muurahaisten ja perhosten suolajistoa. Luonnontilaisilla soilla runsaana esiintyvän rahkasammalen (Sphagnum) peittävyys puolestaan korreloi positiivisesti suolajiston runsauden kanssa, etenkin maakiitäjäisillä ja hämähäkeillä (Artikkeli I), vaaksiaisilla (Artikkeli II) ja viitteellisesti myös muurahaisilla (Artikkeli III). Matala puusto (1,5-3 m) ja toukkien ravintokasvien peittävyys olivat soiden perhoslajistolle (Artikkeli IV) keskeisimmät ympäristömuuttujat. Mitä erikoistuneempi soiden selkärangatonlajisto oli, sitä enemmän se oli riippuvainen luonnontilaisten soiden rakennepiirteistä ja sitä herkemmin ne reagoivat haitalliseen ihmistoimintaan. Soiden ennallistamistoimet (korkeiden puiden poisto, pienten puiden jättäminen ja veden pinnan nosto) osoittautuivat toimiviksi keinoksi palauttaa ja ylläpitää soiden rakennepiirteitä ja luoda sopivaa elinympäristöä vaateliaille suolajeille. Jo 1-3 vuoden kuluttua ennallistamisesta oli alueen selkärangatonlajisto kehittynyt siten, että osa erikoistuneista ja vaateliaista suolajeista oli runsastunut ja lajistorakenne oli kehittymässä kohti luonnontilaisten soiden lajiston rakennetta. Soiden ennallistaminen osoittautui toimivaksi keinoksi hillitä selkärangatonlajiston homogenisaatiota. Ennallistamisen kohdentaminen arvokkaisiin suoluontokohteisiin on hyödyllistä, mutta hyviä tuloksia voi saada aikaan myös pienialaisilla soilla kaupungeissa

The effects of drainage and restoration of pine mires on habitat structure, vegetation and ants

Habitat loss and degradation are the main threats to biodiversity worldwide. For example, nearly 80% of peatlands in southern Finland have been drained. There is thus a need to safeguard the remaining pristine mires and to restore degraded ones. Ants play a pivotal role in many ecosystems and like many keystone plant species, shape ecosystem conditions for other biota. The effects of mire restoration and subsequent vegetation succession on ants, however, are poorly understood. We inventoried tree stands, vegetation, water-table level, and ants (with pitfall traps) in nine mires in southern Finland to explore differences in habitats, vegetation and ant assemblages among pristine, drained (30-40 years ago) and recently restored (1-3 years ago) pine mires. We expected that restoring the water-table level by ditch filling and reconstructing sparse tree stands by cuttings will recover mire vegetation and ants. We found predictable responses in habitat structure, floristic composition and ant assemblage structure both to drainage and restoration. However, for mire-specialist ants the results were variable and longer-term monitoring is needed to confirm the success of restoration since these social insects establish perennial colonies with long colony cycles. We conclude that restoring the water-table level and tree stand structure seem to recover the characteristic vegetation and ant assemblages in the short term. This recovery was likely enhanced because drained mires still had both acrotelm and catotelm, and connectedness was still reasonable for mire organisms to recolonize the restored mires either from local refugia or from populations of nearby mires.Peer reviewe

The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project

© 2016 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. The PREDICTS project—Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)—has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity

The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

Biodiversity continues to decline in the face of increasing anthropogenic pressuressuch as habitat destruction, exploitation, pollution and introduction ofalien species. Existing global databases of species’ threat status or populationtime series are dominated by charismatic species. The collation of datasets withbroad taxonomic and biogeographic extents, and that support computation ofa range of biodiversity indicators, is necessary to enable better understanding ofhistorical declines and to project – and avert – future declines. We describe andassess a new database of more than 1.6 million samples from 78 countries representingover 28,000 species, collated from existing spatial comparisons oflocal-scale biodiversity exposed to different intensities and types of anthropogenicpressures, from terrestrial sites around the world. The database containsmeasurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35)biodiversity hotspots and 16 (of 17) megadiverse countries. The database containsmore than 1% of the total number of all species described, and more than1% of the described species within many taxonomic groups – including floweringplants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopteransand hymenopterans. The dataset, which is still being added to, istherefore already considerably larger and more representative than those usedby previous quantitative models of biodiversity trends and responses. The databaseis being assembled as part of the PREDICTS project (Projecting Responsesof Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk).We make site-level summary data available alongside this article. The full databasewill be publicly available in 2015

Community completeness as a measure of restoration success: multiple-study comparisons across ecosystems and ecological groups

When restoring habitat for biodiversity, the most effective outcome will be achieved by restoration projects which target several organism groups or ecosystem types. Such integrated approaches require direct comparisons among different ecological communities while evaluating success of restoration. The Community Completeness Index (CCI) is a recently developed metric that allows such comparisons by accounting for both present and absent but otherwise suitable taxa. We empirically evaluated the applicability of CCI for assessing the outcome of ecological restoration. We analyzed how species richness and the completeness of ecological communities recover after restoration, for different ecological groups and ecosystem types, and how it develops over time after restoration. Analyses were performed on 18 datasets with per site presence-absence data from Northern Europe. Each dataset represented one of the three habitat types (mire, forest, grassland) and different ecological groups (plants, flying insects, epigeic invertebrates). Datasets contained pristine, degraded and restored sites. We calculated the dark diversity and subsequently CCI based on species co-occurrences. Our multiple-study analyses revealed that CCI of grassland plant communities increased faster after restoration than invertebrate communities or plant communities in forests and mires. In addition, flying insect communities demonstrated significantly highest CCI in pristine mires. Some results were significant only for richness but not for CCI indicating species pool effect. Finally, completeness and species richness of restored communities increased with time since restoration. As such, our study demonstrated that CCI is a useful tool in evaluating restoration success across different organism groups and ecosystem types

Forest biomass, soil and biodiversity relationships originate from biogeographic affinity and direct ecological effects

Ecosystem biomass, soil conditions and the diversity of different taxa are often interrelated. These relationships could originate from biogeographic affinity (varying species pools) or from direct ecological effects within local communities. Disentangling regional and local causes is challenging as the former might mask the latter in natural ecosystems with varying habitat conditions. However, when the species pool contribution is considered in statistics, local ecological effects might be detected. In this study we disentangle the indirect effects of the species pool and direct ecological effects on the complex relationships among wood volume, soil conditions and diversities of different plant and fungal groups in 100 old-growth forest sites (10 x 10 m) at the border of boreal and nemoral zones in northern Europe. We recorded all species for different vegetation groups: woody and herbaceous vascular plants, terricolous and epiphytic bryophytes and lichens. Fungal communities were detected by DNA-based analyses from soil samples. Above-ground wood volume was used as a proxy of biomass. We measured soil pH and nutrient content and obtained modelled climate parameters for each site. Species pool effect was considered by dividing sites into boreal and nemoral groups based on community composition. In order to disentangle direct and indirect effects, we applied variation partitioning, and raw and partial correlations. We found many significant positive relationships among studied variables. Many of these relationships were associated to boreal and nemoral species pools, thus indicating that biogeographic affinity of interacting plants and fungi largely defines forest diversity and functioning. At the same time, several relationships were significant also after considering biogeography: woody plant and ectomycorrhizal fungi diversities with wood volume, many plant and fungal groups with each other, or with soil conditions. These direct ecological interactions could be considered in forestry practices to achieve both economic gain and maintenance of biodiversity

Quantifying and addressing the prevalence and bias of study designs in the environmental and social sciences [Elektronisk resurs]

Building trust in science and evidence-based decision-making depends heavily on the credibility of studies and their findings. Researchers employ many different study designs that vary in their risk of bias to evaluate the true effect of interventions or impacts. Here, we empirically quantify, on a large scale, the prevalence of different study designs and the magnitude of bias in their estimates. Randomised designs and controlled observational designs with pre-intervention sampling were used by just 23% of intervention studies in biodiversity conservation, and 36% of intervention studies in social science. We demonstrate, through pairwise within-study comparisons across 49 environmental datasets, that these types of designs usually give less biased estimates than simpler observational designs. We propose a model-based approach to combine study estimates that may suffer from different levels of study design bias, discuss the implications for evidence synthesis, and how to facilitate the use of more credible study designs. Randomised controlled experiments are the gold standard for scientific inference, but environmental and social scientists often rely on different study designs. Here the authors analyse the use of six common study designs in the fields of biodiversity conservation and social intervention, and quantify the biases in their estimates

Community completeness as a measure of restoration success: multiple-study comparisons across ecosystems and ecological groups

AbstractWhen restoring habitat for biodiversity, the most effective outcome will be achieved by restoration projects which target several organism groups or ecosystem types. Such integrated approaches require direct comparisons among different ecological communities while evaluating success of restoration. The Community Completeness Index (CCI) is a recently developed metric that allows such comparisons by accounting for both present and absent but otherwise suitable taxa. We empirically evaluated the applicability of CCI for assessing the outcome of ecological restoration. We analyzed how species richness and the completeness of ecological communities recover after restoration, for different ecological groups and ecosystem types, and how it develops over time after restoration. Analyses were performed on 18 datasets with per site presence-absence data from Northern Europe. Each dataset represented one of the three habitat types (mire, forest, grassland) and different ecological groups (plants, flying insects, epigeic invertebrates). Datasets contained pristine, degraded and restored sites. We calculated the dark diversity and subsequently CCI based on species co-occurrences. Our multiple-study analyses revealed that CCI of grassland plant communities increased faster after restoration than invertebrate communities or plant communities in forests and mires. In addition, flying insect communities demonstrated significantly highest CCI in pristine mires. Some results were significant only for richness but not for CCI indicating species pool effect. Finally, completeness and species richness of restored communities increased with time since restoration. As such, our study demonstrated that CCI is a useful tool in evaluating restoration success across different organism groups and ecosystem types.</jats:p