Browsing by Subject "biogeography"

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  • Fondi, Marco; Karkman, Antti; Tamminen, Manu V.; Bosi, Emanuele; Virta, Marko; Fani, Renato; Alm, Eric; McInerney, James O. (2016)
    The spatial distribution of microbes on our planet is famously formulated in the Baas Becking hypothesis as everything is everywhere but the environment selects." While this hypothesis does not strictly rule out patterns caused by geographical effects on ecology and historical founder effects, it does propose that the remarkable dispersal potential of microbes leads to distributions generally shaped by environmental factors rather than geographical distance. By constructing sequence similarity networks from uncultured environmental samples, we show that microbial gene pool distributions are not influenced nearly as much by geography as ecology, thus extending the Bass Becking hypothesis from whole organisms to microbial genes. We find that gene pools are shaped by their broad ecological niche (such as sea water, fresh water, host, and airborne). We find that freshwater habitats act as a gene exchange bridge between otherwise disconnected habitats. Finally, certain antibiotic resistance genes deviate from the general trend of habitat specificity by exhibiting a high degree of cross-habitat mobility. The strong cross-habitat mobility of antibiotic resistance genes is a cause for concern and provides a paradigmatic example of the rate by which genes colonize new habitats when new selective forces emerge.
  • Guo, Baocheng; Fang, Bohao; Shikano, Takahito; Momigliano, Paolo; Wang, Cui; Kravchenko, Alexandra; Merilä, Juha (2019)
    Hybridization and convergent evolution are phenomena of broad interest in evolutionary biology, but their occurrence poses challenges for reconstructing evolutionary affinities among affected taxa. Sticklebacks in the genus Pungitius are a case in point: evolutionary relationships and taxonomic validity of different species and populations in this circumpolarly distributed species complex remain contentious due to convergent evolution of traits regarded as diagnostic in their taxonomy, and possibly also due to frequent hybridization among taxa. To clarify the evolutionary relationships among different Pungitius species and populations globally, as well as to study the prevalence and extent of introgression among recognized species, genomic data sets of both reference genome-anchored single nucleotide polymorphisms and de novo assembled RAD-tag loci were constructed with RAD-seq data. Both data sets yielded topologically identical and well-supported species trees. Incongruence between nuclear and mitochondrial DNA-based trees was found and suggested possibly frequent hybridization and mitogenome capture during the evolution of Pungitius sticklebacks. Further analyses revealed evidence for frequent nuclear genetic introgression among Pungitius species, although the estimated proportions of autosomal introgression were low. Apart from providing evidence for frequent hybridization, the results challenge earlier mitochondrial and morphology-based hypotheses regarding the number of species and their affinities in this genus: at least seven extant species can be recognized on the basis of genetic data. The results also shed new light on the biogeographical history of the Pungitius-complex, including suggestion of several trans-Arctic invasions of Europe from the Northern Pacific. The well-resolved phylogeny should facilitate the utility of this genus as a model system for future comparative evolutionary studies.
  • Kunttu, Panu; Helo, Teppo; Kulju, Matti; Julkunen, Jari; Pennanen, Jorma; Shiryaev, Anton G.; Lehtonen, Hannu; Kotiranta, Heikki (Polish Botanical Society, 2019)
    Acta Mycologica 2019;54(2):1128
    Knowledge of the Finnish aphyllophoroid funga has increased substantially in recent years. In this article, we present two species new to Finland: Spiculogloea subminuta Hauerslev and Typhula suecica I. Olariaga, G. Corriol, I. Salcedo & K. Hansen, and document Sistotrema luteoviride Kotir. & K.-H. Larss. for the third time globally. We also contribute 50 new records of 33 nationally rare species (with a maximum of ten previous records in Finland) and list 52 regionally new species, found for the first time in a certain subzone of the boreal vegetation zone in Finland. Each record is enclosed and contains notes on the substrate. Furthermore, the ecology of the nationally new species and the distribution of rare species are discussed.
  • Lindholm, Tapio; Jakovlev, Jevgeni; Kravchenko, Alexey (Finnish Environment Institute, 2015)
    Reports of the Finnish Environment Institute 40/2014
    Zaonezhye Peninsula (Zaonezhsky Peninsula; Заонежский полуостров in Russian transcription) is situated on the northwestern coast of Lake Onega in the Republic of Karelia, Russia. The territory of Zaonezhye is unique in that it contains nearly every type of terrain and unconsolidated sediment known in the vast expanses of northwest Russia. It is also eastern part of Fennoscandian shield. It is characterized by a high diversity of basic limestone and carbonate rocks that determine the fertility of local soils as well as the unique diversity of habitats, flora and fauna. Numerous rare calciphile plant and lichen species are found here, as well as rich, eutrophic wetlands. Long-term farming and animal husbandry have led to a large number of grassland communities in the area. As a result, a mosaic structure of diverse habitats has evolved here. Europe’s second largest lake, Lake Onega, with its clear and deep waters also affect the local climate, making it milder. This report provides for the first time detailed species lists of vascular plants, bryophytes, lichens, wood-growing fungi and insects covering the entire Zaonezhye Peninsula, Kizhi archipelago and other adjacent islands. The most important sites for protection were observed, and six new nature monuments in the southern and southerneast parts of Zaonezhye Peninsula are recommended to be established. This publication contents following articles characterizing nature of Zaonezhye area: 1. Geology and physical geography: 1.1.Geological description, 1.2. Geomorphology and Quaternary deposits, 1.3. Hydrological characteristics, 1.4. Soil cover, 1.5. Palaeogeography, 1.6. Existing and planned protected areas; 2. Landscapes and ecosystems: 2.1. Modern landscapes of Zaonezhye, 2.2. Landscape structure, 2.3. Structure of the forest covered land and forest stands, 2.4. Forest structures, 2.5. Mires, 2.6. Meadows; 3. Flora and fauna: 3.1. Vascular plants, 3.2. Bryophyte flora, 3.3 Species list of lichens and allied fungi, 3.4. Red listed and indicator lichens, 3.5. Aphyllophoroid fungi and 3.6. Insect fauna. 3.7. Localities in Zaonezhye area used in species lists of vascular plants, bryophytes, lichens, fungi and insects, and their toponyms.
  • Woolley, Skipton; Bax, Nicolas; Currie, Jock; Dunn, Daniel; Hansen, Cecilie; Hill, Nicole; O'Hara, Timothy; Ovaskainen, Otso; Sayre, Roger; Vanhatalo, Jarno; Dunstan, Piers (2020)
    Bioregions are important tools for understanding and managing natural resources. Bioregions should describe locations of relatively homogenous assemblages of species occur, enabling managers to better regulate activities that might affect these assemblages. Many existing bioregionalization approaches, which rely on expert-derived, Delphic comparisons or environmental surrogates, do not explicitly include observed biological data in such analyses. We highlight that, for bioregionalizations to be useful and reliable for systems scientists and managers, the bioregionalizations need to be based on biological data; to include an easily understood assessment of uncertainty, preferably in a spatial format matching the bioregions; and to be scientifically transparent and reproducible. Statistical models provide a scientifically robust, transparent, and interpretable approach for ensuring that bioregions are formed on the basis of observed biological and physical data. Using statistically derived bioregions provides a repeatable framework for the spatial representation of biodiversity at multiple spatial scales. This results in better-informed management decisions and biodiversity conservation outcomes.
  • Farstad, Miia (Helsingin yliopisto, 2021)
    Due to the harsh conditions in high latitude alpine and arctic regions, climate or land use changes make them very vulnerable. Thus, it is vital to study the habitats of these regions and increase our understanding of what factors impact species distributions. Species distribution modelling can be used to predict possible habitats for species and further inspect the relationships between different environmental variables and species. Generally, these species distribution models have been created using variables describing the topographical and climatic conditions of the study area. Recently there has been more evidence supporting the inclusion of biotic variables to species distribution models at all scales. Including biotic variables can be difficult, as these relationships can be challenging to quantify. This study uses the Normalized Difference Vegetation Index (NDVI) as a surrogate for plant biomass, thus representing biotic interactions. This study aims to answer what are the relationships between environmental variables and the predicted distributions and will including a biotic variable improve the species distribution models. The study data includes observational data from 683 arctic and alpine plant species from Norway, Sweden, and Finland. The observation data were collected from the three national databanks of Norway, Sweden and Finland and completed with observations from the Global Biodiversity Information Facility and observation data collected by the BioGeoClimate Modelling Lab. The cohesive study area was outlined with the biogeographical regions defined by the European Environment Agency. Overall, six environmental variables are used in this study: annual mean temperature, the maximum temperature of the warmest month, annual precipitation, elevation difference in a cell, bedrock class, and NDVI. The NDVI data was gathered by NASA’s MODIS sensors. The observations and the environmental variables were projected into a grid consisting of 1 x 1 km cells covering the whole study area. This study uses the ensemble modelling technique with four individual modelling methods: generalized linear models (GLM), generalized additive models (GAM), generalized boosted models (GBM) and random forests (RF). The modelling process consisted of two modelling rounds so that the impact of NDVI could be evaluated. The first modelling round included all the environmental variables except NDVI (the topoclimate model) and the second modelling round included all the environmental variables (the full model). The two temperature variables, annual mean temperature and the maximum temperature of the warmest month, had the highest mean variable importance values. With the topoclimate model, annual precipitation ranked third with the rest of the climate variables, but when NDVI was added to the models, it rose above annual precipitation. Overall, among the studied arctic and alpine species, the variable importance values of both the edaphic and topographical variables were low. In general, both the topoclimate models and full models performed very well. The mean AUC- and TSS-values were all higher for the full models, indicating that including a biotic variable improved the models. When the binary predictions of both modelling rounds were compared, it was clear that NDVI refined the projected distributions for most species. The results from this study confirm the discovery that including a biotic variable, such as NDVI, has the potential to increase the predictive power of species distribution models. One of the main problems with including biotic variables in species distribution models has been the difficulty of quantifying biotic interactions. NDVI can thus be a promising tool to overcome these difficulties, as it is one of the most direct variables to describe ecosystem productivity, can be acquired at various scales, and as remotely sensed data, it can also cover areas that are difficult to access.
  • Kunttu, Panu; Helo, Teppo; Kulju, Matti; Julkunen, Jari; Kotiranta, Heikki (Finnish Mycological Society, 2020)
    Karstenia Mycological Journal 58, 1 (2020)
    We contribute to the knowledge on the occurrences and distributions of both aphyllophoroid and heterobasidioid fungi in Finland. We present four species new to Finland, i.e. Helicogloea sebacea, Phanerochaete cremeo-ochracea, Steccherinum cremeoalbum, and Uncobasidium luteolum, as well as 46 new records (locations) of 34 rare or rarely collected species. Additionally, we report on 40 species considered new to a certain subzone of the boreal forest vegetation zone in Finland. These records contain notes on their substrata, and the ecology and distribution of nationally new species are briefly discussed.
  • Hill, Nicole; Woolley, Skipton N. C.; Foster, Scott; Dunstan, Piers K.; McKinlay, John; Ovaskainen, Otso; Johnson, Craig (2020)
    Areas that contain ecologically distinct biological content, called bioregions, are a central component to spatial and ecosystem-based management. We review and describe a variety of commonly used and newly developed statistical approaches for quantitatively determining bioregions. Statistical approaches to bioregionalization can broadly be classified as two-stage approaches that either 'Group First, then Predict' or 'Predict First, then Group', or a newer class of one-stage approaches that simultaneously analyse biological data with reference to environmental data to generate bioregions. We demonstrate these approaches using a selection of methods applied to simulated data and real data on demersal fish. The methods are assessed against their ability to answer several common scientific or management questions. The true number of simulated bioregions was only identified by both of the one-stage methods and one two-stage method. When the number of bioregions was known, many of the methods, but not all, could adequately infer the species, environmental and spatial characteristics of bioregions. One-stage approaches, however, do so directly via a single model without the need for separate post-hoc analyses and additionally provide an appropriate characterization of uncertainty. One-stage approaches provide a comprehensive and consistent method for objectively identifying and characterizing bioregions using both biological and environmental data. Potential avenues of future development in one-stage methods include incorporating presence-only and multiple data types as well as considering functional aspects of bioregions.
  • Graco-Roza, Caio; Aarnio, Sonja; Abrego, Nerea; Acosta, Alicia T. R.; Alahuhta, Janne; Altman, Jan; Angiolini, Claudia; Aroviita, Jukka; Attorre, Fabio; Baastrup-Spohr, Lars; Barrera-Alba, Jose J.; Belmaker, Jonathan; Biurrun, Idoia; Bonari, Gianmaria; Bruelheide, Helge; Burrascano, Sabina; Carboni, Marta; Cardoso, Pedro; Carvalho, Jose C.; Castaldelli, Giuseppe; Christensen, Morten; Correa, Gilsineia; Dembicz, Iwona; Dengler, Jurgen; Dolezal, Jiri; Domingos, Patricia; Erös, Tibor; Ferreira, Carlos E. L.; Filibeck, Goffredo; Floeter, Sergio R.; Friedlander, Alan M.; Gammal, Johanna; Gavioli, Anna; Gossner, Martin M.; Granot, Itai; Guarino, Riccardo; Gustafsson, Camilla; Hayden, Brian; He, Siwen; Heilmann-Clausen, Jacob; Heino, Jani; Hunter, John T.; Huszar, Vera L. M.; Janisova, Monika; Jyrkankallio-Mikkola, Jenny; Kahilainen, Kimmo K.; Kemppinen, Julia; Kozub, Lukasz; Kruk, Carla; Kulbiki, Michel; Kuzemko, Anna; Christiaan le Roux, Peter; Lehikoinen, Aleksi; Teixeira de Lima, Domenica; Lopez-Urrutia, Angel; Lukacs, Balazs A.; Luoto, Miska; Mammola, Stefano; Marinho, Marcelo M.; Menezes, Luciana S.; Milardi, Marco; Miranda, Marcela; Moser, Gleyci A. O.; Mueller, Joerg; Niittynen, Pekka; Norkko, Alf; Nowak, Arkadiusz; Ometto, Jean P.; Ovaskainen, Otso; Overbeck, Gerhard E.; Pacheco, Felipe S.; Pajunen, Virpi; Palpurina, Salza; Picazo, Felix; Prieto, Juan A. C.; Rodil, Ivan F.; Sabatini, Francesco M.; Salingre, Shira; De Sanctis, Michele; Segura, Angel M.; da Silva, Lucia H. S.; Stevanovic, Zora D.; Swacha, Grzegorz; Teittinen, Anette; Tolonen, Kimmo T.; Tsiripidis, Ioannis; Virta, Leena; Wang, Beixin; Wang, Jianjun; Weisser, Wolfgang; Xu, Yuan; Soininen, Janne (2022)
    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.
  • Ribas, Camila C.; Aleixo, Alexandre (2019)
    Amazonia has been a focus of interest since the early days of biogeography as an intrinsically complex and extremely diverse region. This region comprises an intricate mosaic that includes diverse types of forest formations, flooded environments and open vegetation. Increased knowledge about the distribution of species in Amazonia has led to the recognition of complex biogeographic patterns. The confrontation of these biogeographic patterns with information on the geological and climatic history of the region has generated several hypotheses dedicated to explain the origin of the biological diversity. Genomic information, coupled with knowledge of Earth's history, especially the evolution of the Amazonian landscape. presents fascinating possibilities for understanding the mechanisms that govern the origin and maintenance of diversity patterns in one of the most diverse regions of the world. For this we will increasingly need more intense and coordinated interactions between researchers studying biotic diversification and the evolution of landscapes. From the interaction between these two fields of knowledge that are in full development, an increasingly detailed understanding of the historical mechanisms related to the origin of the species will surely arise.
  • Brittain, John E.; Heino, Jani; Friberg, Nikolai; Aroviita, Jukka; Kahlert, Maria; Karjalainen, Satu‐Maaria; Keck, François; Lento, Jennifer; Liljaniemi, Petri; Mykrä, Heikki; Schneider, Susanne C.; Ylikörkkö, Jukka (Blackwell Scientific, 2022)
    Freshwater Biology
    1. Arctic freshwaters support biota adapted to the harsh conditions at these latitudes, but the climate is changing rapidly and so are the underlying environmental filters. Currently, we have limited understanding of broad-scale patterns of Arctic riverine biodiversity and the correlates of α- and β-diversity. 2. Using information from a database set up within the scope of the Arctic Council's Conservation of Arctic Flora and Fauna Circumpolar Biodiversity Monitoring Plan, we analysed patterns and correlates of α- and β-diversity in benthic diatom and macroinvertebrate communities across northern Norway, Sweden, and Finland. We analysed variation in total β-diversity and its replacement and richness difference components in relation to location of the river reach and its drainage basin (Baltic Sea in the south, the Barents Sea in the east and the north, and the Norwegian Sea in the west), in addition to climate and environmental variables. 3. In both macroinvertebrates and diatoms, the replacement and richness difference components showed wide variation. For macroinvertebrates, the richness difference component was the more important, whereas for diatoms, the replacement component was the more important in contributing to variation in β-diversity. There was no significant difference in β-diversity between the three main drainage basins, but species composition differed among the drainage basins. 4. Based on the richness difference component of β-diversity, climate variables were most strongly associated with community variation in macroinvertebrates. In diatoms, both environmental and climate variables were strongly correlated with community compositional variation. In both groups, there were also significant differences in α-diversity among the three main drainage basins, and several taxa were significant indicators of one of these drainage basins. Alpha diversity was greater in areas with a continental climate, while the oceanic areas in the west harboured greatly reduced flora and fauna. 5. The correlates of biodiversity were relatively similar in macroinvertebrates and diatoms. Climate variables, in particular temperature, were the most strongly associated with biodiversity patterns in the Arctic rivers of Fennoscandia. Sedimentary geology may be associated with increased productivity and, to a lesser extent, with sensitivity to acidification. There was considerable variation in community composition across Arctic Fennoscandia, indicating the necessity of protecting several stream reaches or even whole catchments within each region to conserve total riverine biodiversity. Furthermore, it is likely that the predicted changes in temperature in Arctic areas will influence riverine diversity patterns across Fennoscandia.
  • Hill, Matthew J.; Heino, Jani; White, James C.; Ryves, David B.; Wood, Paul J. (2019)
    Biological Conservation 237: 348-357
    Understanding the spatial patterns and environmental drivers of freshwater diversity and community structure is a key challenge in biogeography and conservation biology. However, previous studies have focussed primarily on taxonomic diversity and have largely ignored the phylogenetic and functional facets resulting in an incomplete understanding of the community assembly. Here, we examine the influence of local environmental, hydrological proximity effects, land-use type and spatial structuring on taxonomic, functional and phylogenetic (using taxonomic relatedness as a proxy) alpha and beta diversity (including the turnover and nestedness-resultant components) of pond macroinvertebrate communities. Ninety-five ponds across urban and non-urban land-uses in Leicestershire, UK were examined. Functional and phylogenetic alpha diversity were negatively correlated with species richness. At the alpha scale, functional diversity and taxonomic richness were primarily determined by local environmental factors while phylogenetic alpha diversity was driven by spatial factors. Compositional variation (beta diversity) of the different facets and components of functional and phylogenetic diversity were largely determined by local environmental variables. Pond surface area, dry phase length and macrophyte cover were consistently important predictors of the different facets and components of alpha and beta diversity. Our results suggest that pond management activities aimed at improving biodiversity should focus on improving and/or restoring local environmental conditions. Quantifying alpha and beta diversity of the different biodiversity facets facilitates a more accurate assessment of patterns in diversity and community structure. Integrating taxonomic, phylogenetic and functional diversity into conservation strategies will increase their efficiency and effectiveness, and maximise biodiversity protection in human-modified landscapes.
  • Moura, Carina Carneiro de Melo; Fernandes, Alexandre M.; Aleixo, Alexandre; Pereira de Araujo, Helder Farias; Mariano, Erich de Freitas; Wink, Michael (2020)
    We focus on reconstructing a spatiotemporal scenario of diversification of a widespread South American species, the Pectoral Sparrow Arremon taciturnus (Aves: Passerellidae). This species is widely distributed in both the humid and the dry forests of South America and therefore provides an interesting model for understanding the connection between different biomes of South America. We examined nucleotide sequences of the mitochondrial genes Cytochrome b (cyt-b) and NADH subunit 2 (ND2) from 107 specimens, and one nuclear marker (intron 7 of the beta-fibrinogen gene) from a subset of samples collected across the distribution ranges of A. t. taciturnus and A. t. nigrirostris. Six major lineages were recovered in the phylogenies that displayed high levels of variance of allele frequencies and corresponded to distinct geographical locations. The estimation of divergence times provided evidence that diversification of the six lineages of the Pectoral Sparrow occurred throughout the Late Pleistocene across major cis-Andean biomes and Amazonian interfluves. Our dataset for A. taciturnus provides further evidence that rivers in Amazonia constitute barriers promoting allopatric speciation, with occasional sharing of alleles among lineages, particularly those with adjacent distributions.
  • Buechley, Evan R.; Santangeli, Andrea; Girardello, Marco; Neate-Clegg, Montague H.C.; Oleyar, Dave; McClure, Christopher J.W.; Şekercioğlu, Çagan H. (2019)
    Abstract Aim Raptors serve critical ecological functions, are particularly extinction-prone and are often used as environmental indicators and flagship species. Yet, there is no global framework to prioritize research and conservation actions on them. We identify for the first time the factors driving extinction risk and scientific attention on raptors and develop a novel research and conservation priority index (RCPI) to identify global research and conservation priorities. Location Global. Methods We use random forest models based on ecological traits and extrinsic data to identify the drivers of risk and scientific attention in all raptors. We then map global research and conservation priorities. Lastly, we model where priorities fall relative to country-level human social indicators. Results Raptors with small geographic ranges, scavengers, forest-dependent species and those with slow life histories are particularly extinction-prone. Research is extremely biased towards a small fraction of raptor species: 10 species (1.8% of all raptors) account for one-third of all research, while one-fifth of species have no publications. Species with small geographic ranges and those inhabiting less developed countries are greatly understudied. Regions of Latin America, Africa and Southeast Asia are identified as particularly high priority for raptor research and conservation. These priorities are highly concentrated in developing countries, indicating a global mismatch between priorities and capacity for research and conservation. Main conclusions A redistribution of scientific attention and conservation efforts towards developing tropical countries and the least-studied, extinction-prone species is critical to conserve raptors and their ecological functions worldwide. We identify clear taxonomic and geographic research and conservation priorities for all raptors, and our methodology can be applied across other taxa to prioritize scientific investment.
  • Heino, Jani; Alahuhta, Janne (Royal Entomological Society / Wiley & Sons, 2019)
    Ecological Entomology 44: 413-424
    1. Ecogeographical rules refer to recurring patterns in nature, including the latitudinal diversity gradient (LDG), Rapoport's rule and Bergmann's rule, amongst others. In the present study, the existence of these rules was examined for diving beetles (Coleoptera: Dytiscidae), a family of aquatic predatory beetles. 2. Assemblage-level data were analysed for diving beetles, focusing on species richness, local contribution to beta diversity (LCBD), mean range size and mean body size across the biogeographical provinces of Northern Europe. First, each of these variables was correlated with latitude, and then variation in each variable was modelled using actual environmental variables in boosted regression tree analysis. 3. Species richness was found to decrease with latitude, LCBD increased with latitude, mean range size did not show a significant relationship with latitude, and mean body size decreased with latitude. The latter finding was in contrast to Bergmann's rule. The actual environmental variables best predicting variation in these four response variables varied among the models, although they generally included temperature-related and land use variables as the most influential ones. 4. The results obtained in the present study suggest that diving beetles conformed to the LDG, did not follow Rapoport's rule, and showed a reversed latitudinal gradient in the context of Bergmann's rule. In addition, species-poor provinces harboured ecologically most unique faunas, suggesting that species richness and LCBD are complementary measures of biodiversity. 5. Even though general support was not found for most of the ecogeographical rules examined, the findings of the present study are interesting because they suggest that aquatic ectothermic invertebrates may show patterns different from those originally described for terrestrial endothermic vertebrates.
  • Teittinen, Anette; Wang, Jianjun; Stromgard, Simon; Soininen, Janne (2017)
    Aim: Elevational biodiversity patterns are understudied in high-latitude aquatic systems, even though these systems are important for detecting very early impacts of climatic changes on Earth. The aim of this study was to examine the elevational trends in species richness and local contribution to beta diversity (LCBD) of three biofilm microbial groups in freshwater ponds and to identify the key mechanisms underlying these patterns. Location: One hundred and forty-six ponds in subarctic Finland and Norway distributed across the tree line along an elevational gradient of 10-1,038 m a.s.l., spanning from forested landscape to barren boulder fields. Time period: July-August 2015. Major taxa studied: Diatoms, cyanobacteria and non-cyanobacteria. Methods: Generalized linear models were used to identify the most important pond variables explaining richness and LCBD. Structural equation models were used to explore the direct and indirect effects of multiscale drivers on richness and LCBD. Results: Diatom and cyanobacteria richness showed unimodal elevational patterns, whereas non-cyanobacteria richness decreased with increasing elevation. The LCBD-elevation relationship was U-shaped for all three microbial groups. Diatom and cyanobacteria richness and LCBD were best explained by local pond variables, especially by pH. Non-cyanobacteria richness and LCBD were related to pond variables, elevation as a proxy for climatic conditions, and normalized difference vegetation index as a proxy for terrestrial productivity. Main conclusions: Aquatic autotrophs were primarily controlled by environmental filtering, whereas heterotrophic bacteria were also affected by terrestrial productivity and elevation. All studied aspects of microbial diversity were directly or indirectly linked to elevation; therefore, climatic changes may greatly alter aquatic microbial assemblages.
  • Heino, Jani; Alahuhta, Janne; Fattorini, Simone (Wiley & Sons, 2019)
    Journal of Biogeography 2019; 46: 2548– 2557
    Aim Ecogeographical patterns have been widely studied in endothermic vertebrates, but relatively few studies have simultaneously examined patterns and causes of gradients in species richness, range size and body size in ectothermic insects. We examined patterns in species richness, mean range size and mean body size of ground beetle assemblages across the biogeographical provinces of Northern Europe, a region that was mostly covered by ice sheets during the latest Ice Age and that presents strong contemporary climatic gradients. Location Northern Europe. Methods We used literature information on the occurrence of ground beetles, and analysed patterns in species richness, mean range size and mean body size across the provinces using generalized linear models and boosted regression tree (BRT) analysis. Results We found a strongly decreasing gradient in species richness with increasing latitude, a strongly unimodal range size-latitude relationship, and a weak unimodal body size-latitude relationship in entire ground beetle assemblages. These gradients also varied among four major genera, suggesting that the overall patterns result from the nuances of smaller clades of ground beetles. The relative importance of contemporary environmental drivers also varied between species richness, mean range size and mean body size in BRT analysis. While species richness increased with mean annual temperature, mean range size showed an opposite relationship. Mean body size was most clearly associated with the precipitation of the driest month. Main Conclusions Our findings showed that the latitudinal species richness gradient was strong, and it was closely related to concomitant variation in temperature, whereas variations in mean range size and mean body size were more complex. These findings suggest that the causes for range size and body size variation in insects may be complex, requiring additional insights from studies conducted at local, regional and continental scales.
  • Alahuhta, Janne; Lindholm, Marja; Baastrup-Spohr, Lars; García-Girón, Jorge; Toivanen, Maija; Heino, Jani; Murphy, Kevin (Elsevier, 2021)
    Aquatic Botany 168: 103325
    Broad-scale studies of species distributions and diversity have contributed to the emergence of general macroecological rules. These rules are typically founded on research using well-known terrestrial taxa as models and it is thus uncertain whether aquatic macrophytes follow these macroecological rules. Our purpose is to draw together available information from broad-scale research on aquatic macrophytes growing in lakes, ponds, wetlands, rivers and streams. We summarize how different macroecological rules fit the patterns shown by freshwater plants at various spatial scales. Finally, we outline future actions which should be taken to advance macroecological research on freshwater plants. Our review suggested that some macroecological patterns are relatively well-evidenced for aquatic macrophytes, whereas little information exists for others. We found, for example, that the species richness-latitude relationship follows a unimodal pattern, and species turnover prevails over species nestedness, whereas higher nestedness-related richness differences are found in low beta diversity regions. Contrary to terrestrial plants, climate or history seem not to be dominant determinants explaining these broad-scale patterns; instead local explanatory variables (e.g., water quality, such as alkalinity and nutrients, and hydromorphology) are often important for freshwater plants. We identified several knowledge gaps related, for example, to a smaller number of studies in lotic habitats, compared with lentic habitats, lack of spatially-adequate aquatic plant studies, deficiency of comprehensive species traits databases for aquatic macrophytes, and absence of a true phylogeny comprising most freshwater plant lineages. We hope this review will encourage the undertaking of additional macroecological investigations on freshwater plants across broad spatial and temporal scales.
  • Jousimo, Jussi (Helsingfors universitet, 2011)
    Markov random fields (MRF) are popular in image processing applications to describe spatial dependencies between image units. Here, we take a look at the theory and the models of MRFs with an application to improve forest inventory estimates. Typically, autocorrelation between study units is a nuisance in statistical inference, but we take an advantage of the dependencies to smooth noisy measurements by borrowing information from the neighbouring units. We build a stochastic spatial model, which we estimate with a Markov chain Monte Carlo simulation method. The smooth values are validated against another data set increasing our confidence that the estimates are more accurate than the originals.
  • Davydov, E. A.; Yakovchenko, L. S.; Galanina, I. A.; Paukov, A. G.; Frolov, I. V.; Ahti, T. (2021)
    Aspicilia subepiglypta, Buellia subdisciformis, Calogaya arnoldii, Flavoplaca flavocitrina, Lecanora swartzii, and Lecidella scabra are reported as new records for the Russian Far East. Rinodina gennarii and Lecidella asema are newly recorded for the mainland of the Russian Far East. Rare lichens Cladonia subconistea and Leptotrema litophila are newly found in coastal habitats; Caloplaca atroflava is new for Sakhalin Island, and Umbilicaria vellea is new for Kuril Islands.