Drivers of plant traits that allow survival in wetlands

Plants have developed a suite of traits to survive the anaerobic and anoxic soil conditions in wetlands. Previous studies on wetland plant adaptive traits have focused mainly on physiological aspects under experimental conditions, or compared the trait expression of the local species pool. Thus, a comprehensive analysis of potential factors driving wetland plant adaptive traits under natural environmental conditions is still missing.In this study, we analysed three important wetland adaptive traits, i.e. root porosity, root/shoot ratio and underwater photosynthetic rate, to explore driving factors using a newly compiled dataset of wetland plants. Based on 21 studies at 38 sites across different biomes, we found that root porosity was affected by an interaction of temperature and hydrological regime; root:shoot ratio was affected by temperature, precipitation and habitat type; and underwater photosynthetic rate was affected by precipitation and life form. This suggests that a variety of driving mechanisms affect the expression of different adaptive traits.The quantitative relationships we observed between the adaptive traits and their driving factors will be a useful reference for future global methane and denitrification modelling studies. Our results also stress that besides the traditionally emphasized hydrological driving factors, other factors at several spatial scales should also be taken into consideration in the context of future functional wetland ecology.Environmental Biolog

Too much diversity—Multiple definitions of geodiversity hinder its potential in biodiversity research

Geodiversity—the diversity of abiotic features and pro-cesses of the Earth's surface and subsurface—is an increasingly used concept in ecological research. A growing body of scientific literature has provided evidence of positive links between geodiversity and biodiversity. These studies highlight the potential of geodiversity to improve our understanding of biodiversity patterns and to complement current biodiversity conservation practices and strategies. However, definitions of geodiversity in eco-logical research vary widely. This can hinder the progress of geodiversity–biodiversity research and make it difficult to synthesize findings across studies. We therefore call for greater awareness of how geodiversity is currently defined and for more consistent use of the term ‘geodi-versity’ in biodiversity research

Standard of hygiene and immune adaptation in newborn infants

Peer reviewe

Distance decay 2.0-A global synthesis of taxonomic and functional turnover in ecological communities

Aim: Understanding the variation in community composition and species abundances (i.e., beta-diversity) is at the heart of community ecology. A common approach to examine beta-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments. Location: Global. Time period: 1990 to present. Major taxa studied: From diatoms to mammals. Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features. Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances. Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments

Patterns of aquatic macrophytes in the boreal region: implications for spatial scale issues and ecological assessment

Abstract Eutrophication and global warming are increasingly causing deterioration of aquatic ecosystems, and boreal freshwaters are especially vulnerable to these changes. Anthropogenic pressures and landscape characteristics influencing the functioning and structure of ecosystems vary with spatial scale (grain size i.e. study unit and extent i.e. study area). This emphasises that the understanding of spatial scale is a vital element when studying species distribution patterns. Moreover, spatial scale is often neglected in ecological assessments, in which the degree of ecological integrity of an ecosystem is assessed using selected biological groups. One of these groups is aquatic macrophytes. The aims of this thesis were (i) to study the distribution and richness of aquatic macrophytes in the boreal region in Finland at multiple scales and (ii) to evaluate the performance of ecological assessment metrics selected for Finnish lake macrophytes. The spatial extent at which aquatic macrophytes were studied had an important influence on the patterns found. Climatic factors associated with latitudinal and altitudinal gradient determined macrophytes at broad extent, although the patterns changed at finer regional extent. Moreover, this strong effect of climate could lead to the widening of distribution ranges of helophytes in boreal catchments during the 21st century due to the climate change. Many of these species have already widened their range limits during the previous century and increasing temperatures may create new niches for vegetation to colonize. Lake macrophyte richness, turnover and quality metrics showed a clear relationship with nutrient concentration in waters at landscape and regional extent. Helophytes and metrics were positively or inversely negatively related to nutrients, whereas species turnover and other life-form groups had a unimodal or non-significant response to nutrient availability. In addition, land use (agricultural and urban areas and forestry ditch drainage) influenced macrophytes directly through shore morphology changes and indirectly through water quality. Macrophytes were also explained at various scales by area and depth, which were related to habitat heterogeneity, and aquatic plants responded to water ionic and electrical characteristics (pH, alkalinity and conductivity). Ecological quality metrics of macrophytes appeared to be scale dependent, since land use adjacent to the lake shoreline had a higher influence on the metrics compared to land use of the whole catchment. However, the scale-related pattern in the effect of land use was not congruent between metrics, as the Trophic Index showed poorer performance compared to the proportion of type-specific species and Percent Model Affinity. This was presumably due to lack of helophytes in the species pool used and to reference values which were defined across lake types in the Trophic Index. Uneven performance of the metrics derived from different biological groups suggests that an approach integrating multiple lines of evidence on ecological status appears most feasible for assessment of the overall lake status.Tiivistelmä Vesistöjen rehevöityminen ja ilmastonmuutos heikentävät vesiekosysteemien laatua, ja boreaaliset sisävedet ovat erityisen alttiita näiden uhkatekijöiden aiheuttamille muutoksille. Ihmistoiminnan aiheuttamien muutoksien ja luontaisten maisematekijöiden merkitys vesiekosysteemien toimintaan ja rakenteeseen vaihtelee mittakaavan (tutkimusyksikön ja -alueen) mukaan. Kuitenkin spatiaalisen mittakaavan merkitys on usein unohdettu ekologisissa arvioinneissa, joissa selvitetään ekosysteemin luonnontilaisuutta eri biologisilla lajiryhmillä. Vesikasvit ovat yksi usein käytetty biologinen ryhmä järvien ekologissa arvioinneissa. Tämän tutkimuksen tarkoitus on (i) tutkia vesikasvien levinneisyyttä ja runsautta Suomessa useissa mittakaavoissa, ja (ii) arvioida ekologisten luokittelumuuttujien toimivuutta järvien vesikasveilla eri mittakaavoissa. Mittakaava, jossa vesikasveja tutkittiin, vaikutti merkittävästi saatuihin tuloksiin. Leveysasteeseen ja korkeuteen liittyvä gradientti määritti vesikasvien levinneisyyttä alueellisessa mittakaavassa. Lisäksi ilmaston voimakas vaikutus vesikasveihin voi johtaa niiden levinneisyysrajojen laajenemiseen, koska ilmastonmuutos saattaa luoda edullisemmat kasvuolosuhteet kasvillisuudelle tällä vuosisadalla. Monet vesikasvilajit ovat jo levinneet pohjoisemmaksi 1900-luvulla, ja lämpötilojen nousu voi lisätä ekolokeroita vesikasvien levittäytymiselle. Vesikasvien runsaus, lajimäärä ja luokittelumuuttujat olivat selkeästi yhteydessä vesien ravinteisuuteen maisemallisessa ja alueellisessa mittakaavassa. Ilmaversoisilla vesikasveilla ja luokittelumuuttujilla oli positiivinen tai käänteisesti negatiivinen suhde ravinteisiin, kun taas lajimäärä ja muut vesikasvien kasvumuodot olivat unimodaalisessa tai merkityksettömässä yhteydessä ravinteisuuteen. Lisäksi maankäyttö, erityisesti maatalous, kaupunkiasutus ja metsäojitus, vaikutti vesikasveihin suoraan rantavyöhykkeen morfologisin muutoksin tai epäsuorasti ravinteisuuden kautta. Vesikasvien levinneisyyttä ja runsautta selitti myös pinta-ala ja syvyys, jotka liittyivät elinympäristön heterogeenisyyteen, sekä veden fysikaalis-kemialliset ominaisuudet, kuten pH, alkaliniteetti ja sähkönjohtokyky. Ekologiset luokittelumuuttujat olivat riippuvaisia mittakaavasta, koska rantavyöhykkeen läheisellä maankäytöllä oli suurempi merkitys muuttujille kuin koko valuma-alueen maankäytöllä. Kuitenkin mittakaavan merkitys vaihteli eri muuttujien välillä, kun referenssi-indeksi osoitti heikompaa vastetta maankäyttöön eri mittakaavoissa kuin tyyppilajien suhteellinen osuus ja prosenttinen mallin samankaltaisuus. Tämä luultavasti johtui siitä, että referenssi-indeksissä ilmaversoiset vesikasvit puuttuivat tutkittavista lajeista ja referenssiarvot olivat yhteiset riippumatta järvityypistä. Eri biologisiin ryhmiin perustuva luokittelujärjestelmä ilmensi hyvin vaihtelevasti ekologista laatua, minkä vuoksi eri muuttujia yhdistävä menetelmä, joka arvioi vesimuodostuman kokonaistilaa, on toteuttamiskelpoisin lähestymistapa boreaalisissa järvissä

Patterns and mechanisms underlying ecoregion delineation in North American freshwater plants

Abstract Aim: The regionalized patterns of biodiversity distributions are actively studied in terrestrial and marine ecosystems, but much less is known on the geographical patterns of ecoregions founded on freshwater taxa. Here, we studied, for the first time, how well existing freshwater ecoregions describe the geographical distribution of inland water plants. Location: Greenland, continental Canada and USA. Taxon: Freshwater vascular plants of all taxa and multiple functional groups (i.e. growth forms). Methods: Using newly available fine-grained data on freshwater plant distributions, we studied how ecoregions founded on fish are suitable for freshwater plant regionalization across North America. Specifically, we calculated internal homogeneity and distinctness among neighbouring ecoregions in relation to species replacements and richness differences. We also explored how a complex suite of ecogeographical characteristics affect ecoregion delineation of freshwater plants using spatially explicit regression routines. Results: We found a clear geographical patterning of ecoregion robustness for North American freshwater plants, with communities being more internally homogeneous and more similar to one another in Polar and Subtropical inland waters. The degree of internal homogeneity and ecoregion distinctness were almost equally driven by species replacements and richness differences. Considering different life-forms, ecoregion delineation performed best for emergent and floating-leaved plants. Finally, within-ecoregion homogeneity and distinctness were best explained by annual mean temperature and terrain ruggedness, respectively, with mean water alkalinity, ecoregion area and late Quaternary glacial legacies having supplementary effects. Main conclusions: Our findings suggest that selection through climate filtering (e.g. mean annual temperature) is likely the main mechanistic driver of freshwater plant ecoregions. Geographical regionalizations founded on a particular organismal group may not be directly applicable for all taxa but can be a good basis for further adjustments. Our study is a promising starting point for further investigations of geographical delineations for freshwater taxa other than fish

Deciphering land-use influences on boreal lakes to guide landscape planning

Abstract 1. Changes in natural land cover have been pronounced in the last 12,000 years, and land use has intensified in the last century owing to anthropogenic pressures on landscapes. This trend has led to concomitant changes in the abiotic templates and biotic communities of different ecosystems embedded in a landscape. 2. Deciphering the role of land use is key to understand ecological change in boreal landscapes. These landscapes are characterized by large numbers of lakes that have been affected by various anthropogenic factors, of which land use has considerable direct and indirect effects on lakes. 3. In this review, we focus on land use impacts on boreal lakes in a historical perspective. We will consider lake features related to abiotic conditions, biological communities and ecosystem services, and provide potential solutions for planning lake management and conservation in a landscape setting. More specifically, we propose a novel way to characterize lake abiotic, biotic and ecosystem service features by applying the alpha, beta and gamma concept used widely in ecological research. 4. Finally, we highlight situations where this approach could be a valuable addition to existing means to identify lakes that should be reserved for ecosystem services (‘lake-sharing’) and those that are vital for protecting aquatic biodiversity (‘lake-sparing’)

Metacommunity ecology meets biogeography:effects of geographical region, spatial dynamics and environmental filtering on community structure in aquatic organisms

Abstract Metacommunity patterns and underlying processes in aquatic organisms have typically been studied within a drainage basin. We examined variation in the composition of six freshwater organismal groups across various drainage basins in Finland. We first modelled spatial structures within each drainage basin using Moran eigenvector maps. Second, we partitioned variation in community structure among three groups of predictors using constrained ordination: (1) local environmental variables, (2) spatial variables, and (3) dummy variable drainage basin identity. Third, we examined turnover and nestedness components of multiple-site beta diversity, and tested the best fit patterns of our datasets using the “elements of metacommunity structure” analysis. Our results showed that basin identity and local environmental variables were significant predictors of community structure, whereas within-basin spatial effects were typically negligible. In half of the organismal groups (diatoms, bryophytes, zooplankton), basin identity was a slightly better predictor of community structure than local environmental variables, whereas the opposite was true for the remaining three organismal groups (insects, macrophytes, fish). Both pure basin and local environmental fractions were, however, significant after accounting for the effects of the other predictor variable sets. All organismal groups exhibited high levels of beta diversity, which was mostly attributable to the turnover component. Our results showed consistent Clementsian-type metacommunity structures, suggesting that subgroups of species responded similarly to environmental factors or drainage basin limits. We conclude that aquatic communities across large scales are mostly determined by environmental and basin effects, which leads to high beta diversity and prevalence of Clementsian community types

Predicting beta diversity of terrestrial and aquatic beetles using ecogeographical variables:insights from the replacement and richness difference components

Abstract Aim: We examined the responses of the beta diversity of aquatic and terrestrial beetles to ecogeographical variables, including climate, land cover and land use, across Northern Europe. Location: Northern Europe (Denmark, Sweden, Norway and Finland). Methods: Information on the occurrence of ground beetles and diving beetles across Northern European biogeographical provinces was collated from literature sources. Beta diversity was examined using Jaccard dissimilarity coefficient as well as its replacement and richness difference components. Each of the three dissimilarity matrices (responses) was modelled using various ecogeographical variables (predictors) by generalized dissimilarity modelling (GDM). Results: The magnitude of total beta diversity was relatively similar between ground beetles and diving beetles, but the richness difference component contributed more than the replacement component to total beta diversity in ground beetles, whereas the opposite was true for diving beetles. The predictor variables most influential in GDM in accounting for spatial variation in beta diversity varied between the two beetle groups as well as between the replacement and richness difference components. In general, the richness difference component of ground beetles responded strongly to latitude and associated climatic variables, whereas the replacement component of diving beetles varied strongly along the same geographical gradient. Main conclusions: Our findings suggest that the study of the determinants of biodiversity patterns benefits from the partitioning of beta diversity into different components and from comparing terrestrial and aquatic groups. For example, our findings suggest that the strong climatic and land use‐related gradients in beta diversity have important implications for predicting and mitigating the effect of ongoing global change on the composition of regional biotas

Temporal beta diversity of lake plants is determined by concomitant changes in environmental factors across decades

Abstract 1. To comprehensively understand the impact of anthropogenic activities on biodiversity, we must understand how biodiversity has changed over time and what are the underlying processes. A growing body of evidence has shown that beta diversity reveals more about temporal changes in biodiversity compared with alpha diversity. Temporal beta diversity indicates, for example, degrees of change in species composition at single locations through time. 2. We examined whether freshwater plant communities showed different patterns in temporal beta diversity in relation to concomitant changes in environmental conditions across decades. To do this, we used presence–absence data of lake plants for five decades (1940s–2010s) from southern Finland and calculated temporal beta diversity indices (TBI) for each lake between pairs of decades to the whole community, hydrophytes and helophytes. To get insights into possible processes behind the observed trends, we decomposed TBIs into beta diversity contributed by either temporal losses or temporal gains of species. We related TBIs and their loss and gain components to lake landscape position and changes in environmental variables. 3. Based on comparisons of TBIs between the survey decade pairs, the temporal change in aquatic plant communities was modest through decades. Hydrophyte assemblages have changed more than helophyte assemblages. The main changes in temporal beta diversity occurred from the 1940s to the 1970s, when the gain of new species was the dominant process in the lakes throughout the landscape. Following that period, there was only modest changes, but from the 2000s to the 2010s, the dominant process was the loss of species. Temporal changes in environmental conditions played a key role in explaining the TBI. 4. Our results showed that relying on only two survey points in time can result in limited knowledge of the ecological phenomenon under study and, for example, an exceptional year in terms of weather conditions can hinder detecting overall long‐term trends in compositional changes. Therefore, future studies should try to combine data from several decades to overcome the typical limitations of temporal information