Browsing by Subject "habitat"

Sort by: Order: Results:

Now showing items 1-8 of 8
  • Tolonen, Kimmo T.; Karjalainen, Juha; Hämäläinen, Heikki; Nyholm, Kristiina; Rahkola-Sorsa, Minna; Cai, Yongjiu; Heino, Jani (Springer Link, 2020)
    Aquatic Ecology 54 3 (2020)
    Lake littoral environments are heterogeneous, and different organisms typically show specific responses to this environmental variation. We examined local environmental and spatial factors affecting lake littoral biodiversity and the structuring of assemblages of phytoplankton, zooplankton and macroinvertebrates within and among three basins of a large lake system. We explored congruence of species composition and species richness among the studied organism groups to evaluate their general indicator potential to represent spatial variation in other groups. We expected that effects of water chemistry on plankton assemblages were stronger than effects of habitat characteristics. In contrast, we anticipated stronger effects of habitat on macroinvertebrates due to their mainly benthic mode of life. We also expected that within-basin spatial effects would be strongest on macroinvertebrates and weakest on phytoplankton. We predicted weak congruence in assemblage composition and species richness among the organism groups. Phytoplankton assemblages were mainly structured by the shared effects of water chemistry and large-scale spatial factors. In contrast to our expectations, habitat effects were stronger than water chemistry effects on zooplankton assemblages. However, as expected, macroinvertebrate species composition and richness were mainly affected by habitat conditions. Among-group congruence was weak for assemblage composition and insignificant for richness. Albeit weak, congruence was strongest between phytoplankton and zooplankton assemblages, as we expected. In summary, our analyses do not support the idea of using a single organism group as a wholesale biodiversity indicator.
  • da Silva, Pedro Giovâni; Cañedo-Argüelles, Miguel; Bogoni, Juliano André; Heino, Jani (Frontiers Media S.A., 2021)
    Frontiers in Ecology and Evolution 9: 670212
    According to metacommunity theory (Leibold et al., 2004), the structure of local communities results from the interplay between local factors (e.g., environmental filtering, species interactions) and regional factors (e.g., dispersal rates, landscape configuration). The relative importance of these factors is highly dependent on the organisms’ biological traits, landscape connectivity, and the spatial and temporal scales considered (Heino et al., 2015; Tonkin et al., 2018; Viana and Chase, 2019; Almeida-Gomes et al., 2020; Cañedo-Argüelles et al., 2020; Lansac-Tôha et al., 2021). However, the differences in metacommunity assembly mechanisms found among studies are far from being fully understood. The evaluation of temporal dynamics of metacommunities has only emerged recently (Cañedo-Argüelles et al., 2020; Jabot et al., 2020; Li et al., 2020; Lindholm et al., 2021) and the application of the metacommunity theory in other fields, such as biomonitoring, conservation biology or ecosystem restoration, is yet to be fully explored (Bengtsson, 2010; Heino, 2013; Leibold and Chase, 2018; Chase et al., 2020; Cid et al., 2020; Heino et al., 2021). In this Research Topic, our aim was to invite researchers working in different biogeographic regions and ecological systems (Figure 1) to publish a number of innovative papers on metacommunity spatio-temporal dynamics. We expect to obtain a better understanding of how the factors and processes that structure metacommunities vary in space and time, as well as the implications of such dynamics for biodiversity conservation and ecosystem management.
  • Fourcade, Yoan; WallisDeVries, Michiel F.; Kuussaari, Mikko; Swaay, Chris A. M.; Heliölä, Janne; Öckinger, Erik (John Wiley & Sons Ltd, 2021)
    Ecology Letters 24: 5, 950-957
    Habitat fragmentation may present a major impediment to species range shifts caused by climate change, but how it affects local community dynamics in a changing climate has so far not been adequately investigated empirically. Using long-term monitoring data of butterfly assemblages, we tested the effects of the amount and distribution of semi-natural habitat (SNH), moderated by species traits, on climate-driven species turnover. We found that spatially dispersed SNH favoured the colonisation of warm-adapted and mobile species. In contrast, extinction risk of cold-adapted species increased in dispersed (as opposed to aggregated) habitats and when the amount of SNH was low. Strengthening habitat networks by maintaining or creating stepping-stone patches could thus allow warm-adapted species to expand their range, while increasing the area of natural habitat and its spatial cohesion may be important to aid the local persistence of species threatened by a warming climate.
  • Pykälä, Juha (Elsevier, 2019)
    Global Ecology and Conservation 18 (2019), e00610
    Why populations of threatened species disappear is among the key questions in conservation biology. However, very few local and regional studies have attempted to quantify the importance of the various causes. In this investigation, the status of the populations of threatened vascular plants, bryophytes and lichens found between the years 1860–1979 in a national biodiversity hot spot in SW Finland was studied during the years 1990–2008. Of the populations, 82% had disappeared and 18% were re-discovered. The disappearance rate of populations differed between habitats: exceeding 80% in most habitat types whilst being lowest on rock outcrops (58%). Complete destruction of all locally suitable habitats was the main reason for the disappearance of the populations (73%) concerned. Habitat deterioration (including partial habitat loss) was identified as the reason for the disappearance for 22% of the populations. Only for 5% of the populations could it not be revealed whether habitat quality had changed or not, but deterioration of habitat quality or habitat loss is possible even in these cases. For none of the disappeared populations was no change in habitat quality verified. In most cases, habitat loss and deterioration were caused by agriculture or forestry. These results support the conclusion that vascular plant, bryophyte and lichen populations in the boreal landscape have disappeared directly because their habitats have disappeared, declined in size or deteriorated due to forestry, agriculture, construction, mining and pollution. More subtle changes in habitat quality, fragmentation, problems related to small population size per se and other reasons may have contributed to only a few disappearances of local populations. The disappearance rate was similar between the study groups, but the relative importance of reasons for disappearance was different. The results emphasize the importance of habitat protection for threatened vascular plants, bryophytes and lichens.
  • Hosseinzadeh, Mahboubeh Sadat; Farhadi Qomi, Masood; Naimi, Babak; Roedder, Dennis; Kazemi, Seyed Mandi (2018)
    Species distribution models estimate the relationship between species occurrences and environmental and spatial characteristics. Herein, we used maximum entropy distribution modelling (MaxEnt) for predicting the potential distribution of the Plateau Snake Skink Ophiomorus nuchalis on the Iranian Plateau, using a small number of occurrence records (i.e. 10) and environmental variables derived from remote sensing. The MaxEnt model had a high success rate according to test AUC scores (0.912). A remotely sensed enhanced vegetation index (39.1%), and precipitation of the driest month (15.4%) were the most important environmental variables that explained the geographical distribution of O. nuchalis. Our results are congruent with previous studies suggesting that suitable habitat of O. nuchalis is limited to the central Iranian Plateau, although mountain ranges in western and eastern Iran might be environmentally suitable but not accessible.
  • Vilmi, Annika; Tolonen, Kimmo T.; Karjalainen, Satu Maaria; Heino, Jani (Elsevier, 2019)
    Ecological Indicators, 99, 159-166
    We examined how niche position, niche breadth, biological traits and taxonomic relatedness affect interspecific variation in occupancy and abundance of two commonly-used biological indicator groups, i.e. diatoms and macroinvertebrates. We studied 291 diatom and 103 macroinvertebrate species that occupied the littoral zones of a large (305 km2) highly-connected freshwater system. We collated information on the biological traits and taxonomic relatedness of each species. Using principal coordinates analysis, we formed biological trait and taxonomic vectors describing distances between species and used the resulting vectors as predictor variables. As environmental data, we had site-specific physico-chemical variables, which were used in outlying mean index analyses to determine the niche position and niche breadth of each species. We used linear models to study if and how these two niche parameters and biological traits as well as taxonomic relatedness affected occupancy and abundance. We observed positive occupancy-abundance relationships for both diatoms and macroinvertebrates. We further found that, for both groups, occupancy was better explained by the predictor variables compared with abundance. We also observed that niche parameters, especially niche position, were the main determinants of variation in occupancy and abundance for both diatoms and macroinvertebrates. Local abundances of diatom and macroinvertebrate species were also, to a small degree, affected by biological traits or taxonomic relatedness. We further saw that the relationship between niche position and occupancy was negative, indicating that the more marginal the niche position, the rarer a species is. Our findings provide support for the use of diatoms and macroinvertebrates as ecological indicators as their occupancies and abundances were affected by niche parameters, which is not necessarily always clear in challenging study systems with high connectivity (i.e. high movement of material and species) among sites. These findings also suggest that indices using information on species’ occupancy, abundance and niche requirements are useful in environmental assessment.
  • Viitanen, Ville (Helsingin yliopisto, 2017)
    In my Master’s Thesis I researched young lynxes ́ (Lynx lynx) use of habitat during dispersal. When analysing different research materials, I found out what kind of habitats and topography young lynxes use during their dispersal. There haven ́t been many researchs in this area in Finland before, therefore this research is providing new information to the subject. The Natural Resources Institute in Finland provided the tracking materials for the research. In this work I have three research questions. 1.) Does different habitat types affect to dispersal and does the use of habitat types vary between male and female? 2.) Does topography affect to dispersal and how does the topography classes are divided between male and female? 3.) Which sex disperses further? The studied area was Southern Finland, below the city of Jyväskylä. My research material contained nine male and seven female lynxes. The material was collected during years 2008 – 2014. Lynxes in the study had a GPS -collar, enabling position tracking. The gathered positioning points were transferred to ArcGIS 10.3.1 geographic program. Besides positioning points, the Corine Land Cover -2012 habitat map and DEM (Digital elevation model) topography were used in the study. I classified Corine materials to eight different categories and DEM materials set to twenty different categories. I converted the lynxes ́ positioning points into trails. The trail zone was set to four kilometres. Also, an individual zone with a radius of ten meters was set for each positioning point. When analysing these zones, I was able to find out what kind of habitats and topography lynxes use during dispersal. The length of the dispersal was calculated in two ways: A1-B1 the length of the dispersal was the distance between the start and end points. A2-B2 the length of the dispersal was the total length between all positioning points. I used the Mann Whitney -U test for the statistic testing. The results of this study show that male and female lynxes ́ use of habitats in the research area was divided evenly. Two classes showed statistically significant results: females favour peatlands in four kilometers dispersal trail zone. In ten meters positioning point zone females favour more coniferous forest. There were no special characteristics in males ́ use of habitats. The results of composition analyze show that lynxes favour mixed- and coniferous forests and fields. Selection of habitats wasn’t random. There were no difference in the use of topography between males and females, although one topography class was statistically significant. Mainly lynxes favour higher topography. The results show that males disperse further than females. There was, however, one female, whose dispersal was abnormally longer when compared to the other females. There was a strong positive correlation between the total length of the dispersal and the time used for the dispersal Generally there was no difference between the linearity of the dispersal trails of males and females. The results of this Master’s Thesis are used in the national lynx research project.
  • Virkkala, Raimo; Pöyry, Juha; Heikkinen, Risto K.; Lehikoinen, Aleksi; Valkama, Jari (2014)