Browsing by Subject "communities"

Sort by: Order: Results:

Now showing items 1-8 of 8
  • García-Girón, Jorge; Heino, Jani; García-Criado, Francisco; Fernández-Aláez, Camino; Alahuhta, Janne (Wiley Online Library, 2020)
    Ecography 43 8 (2020)
    Biotic interactions are fundamental drivers governing biodiversity locally, yet their effects on geographical variation in community composition (i.e. incidence-based) and community structure (i.e. abundance-based) at regional scales remain controversial. Ecologists have only recently started to integrate different types of biotic interactions into community assembly in a spatial context, a theme that merits further empirical quantification. Here, we applied partial correlation networks to infer the strength of spatial dependencies between pairs of organismal groups and mapped the imprints of biotic interactions on the assembly of pond metacommunities. To do this, we used a comprehensive empirical dataset from Mediterranean landscapes and adopted the perspective that community assembly is best represented as a network of interacting organismal groups. Our results revealed that the co-variation among the beta diversities of multiple organismal groups is primarily driven by biotic interactions and, to a lesser extent, by the abiotic environment. These results suggest that ignoring biotic interactions may undermine our understanding of assembly mechanisms in spatially extensive areas and decrease the accuracy and performance of predictive models. We further found strong spatial dependencies in our analyses which can be interpreted as functional relationships among several pairs of organismal groups (e.g. macrophytes–macroinvertebrates, fish–zooplankton). Perhaps more importantly, our results support the notion that biotic interactions make crucial contributions to the species sorting paradigm of metacommunity theory and raise the question of whether these biologically-driven signals have been equally underappreciated in other aquatic and terrestrial ecosystems. Although more research is still required to empirically capture the importance of biotic interactions across ecosystems and at different spatial resolutions and extents, our findings may allow decision makers to better foresee the main consequences of human-driven impacts on inland waters, particularly those associated with the addition or removal of key species.
  • Iversen, L.L.; Winkel, A.; Baastrup-Spohr, L.; Hinke, A.B.; Alahuhta, J.; Baattrup-Pedersen, A.; Birk, S.; Brodersen, P.; Chambers, P. A.; Ecke, F; Feldmann, T.; Gebler, D.; Heino, J.; Jespersen, T. S.; Moe, S. J.; Riis, T.; Sass, L.; Vestergaard, O.; Maberly, S. C.; Sand-Jensen, K.; Pedersen, O. (American Association for the Advancement of Science, 2019)
    Science Vol. 366, Issue 6467, pp. 878-881
    Unlike in land plants, photosynthesis in many aquatic plants relies on bicarbonate in addition to carbon dioxide (CO2) to compensate for the low diffusivity and potential depletion of CO2 in water. Concentrations of bicarbonate and CO2 vary greatly with catchment geology. In this study, we investigate whether there is a link between these concentrations and the frequency of freshwater plants possessing the bicarbonate use trait. We show, globally, that the frequency of plant species with this trait increases with bicarbonate concentration. Regionally, however, the frequency of bicarbonate use is reduced at sites where the CO2 concentration is substantially above the air equilibrium, consistent with this trait being an adaptation to carbon limitation. Future anthropogenic changes of bicarbonate and CO2 concentrations may alter the species compositions of freshwater plant communities.
  • Lindholm, Marja; Alahuhta, Janne; Heino, Jani; Hjort, Jan; Toivonen, Heikki (Springer Link, 2020)
    Hydrobiologia 847 (2020)
    Functional homogenisation occurs across many areas and organism groups, thereby seriously affecting biodiversity loss and ecosystem functioning. In this study, we examined how functional features of aquatic macrophytes have changed during a 70-year period at community and species levels in a boreal lake district. At the community level, we examined if aquatic macrophyte communities showed different spatial patterns in functional composition and functional richness in relation to main environmental drivers between the time periods. We also observed each species in functional space to assess if species with certain sets of traits have become more common or rare in the 70-year study period. We found changes in the relationship between functional community composition and the environment. The aquatic macrophyte communities showed different patterns in functional composition between the two time periods, and the main environmental drivers for these changes were partly different. Temporal changes in functional richness were only partially linked to concomitant changes in the environment, while stable factors were more important. Species’ functional traits were not associated with commonness or rarity patterns. Our findings revealed that functional homogenisation has not occurred across these boreal lakes, ranging from small oligotrophic forest lakes to larger lakes affected by human impacts.
  • Laine, Anna M.; Lindholm, Tapio; Nilsson, Mats; Kutznetsov, Oleg; Jassey, Vincent E. J.; Tuittila, Eeva-Stiina (John Wiley & Sons Ltd, 2021)
    Journal of Ecology 109, 4 (2021), 1774–1789
    1. Most of the carbon accumulated into peatlands is derived from Sphagnum mosses. During peatland development, the relative share of vascular plants and Sphagnum mosses in the plant community changes, which impacts ecosystem functions. Little is known on the successional development of functional plant traits or functional diversity in peatlands, although this could be a key for understanding the mechanisms behind peatland resistance to climate change. Here we aim to assess how functionality of successive plant communities change along the autogenic peatland development and the associated environmental gradients, namely peat thickness and pH, and to determine whether trait trade-offs during peatland succession are analogous between vascular plant and moss communities. 2. We collected plant community and trait data on successional peatland gradients from post-glacial rebound areas in coastal Finland, Sweden and Russia, altogether from 47 peatlands. This allowed us to analyse the changes in community-weighted mean trait values and functional diversity (diversity of traits) during peatland development. 3. Our results show comparative trait trade-offs from acquisitive species to conservative species in both vascular plant and Sphagnum moss communities during peatland development. However, mosses had higher resistance to environmental change than vascular plant communities. This was seen in the larger proportion of intraspecific trait variation than species turnover in moss traits, while the proportions were opposite for vascular plants. Similarly, the functional diversity of Sphagnum communities increased during the peatland development, while the opposite occurred for vascular plants. Most of the measured traits showed a phylogenetic signal. More so, the species common to old successional stages, namely Ericacae and Sphagna from subgroup Acutifolia were detected as most similar to their phylogenetic neighbours. 4. Synthesis. During peatland development, vegetation succession leads to the dominance of conservative plant species accustomed to high stress. At the same time, the autogenic succession and ecological engineering of Sphagna leads to higher functional diversity and intraspecific variability, which together indicate higher resistance towards environmental perturbations.
  • Cosens, Barbara; Ruhl, J. B.; Soininen, Niko; Gunderson, Lance; Belinskij, Antti; Blenckner, Thorsten; Camacho, Alejandro E.; Chaffin, Brian C.; Craig, Robin Kundis; Doremus, Holly; Glicksman, Robert; Heiskanen, Anna-Stiina; Larson, Rhett; Similä, Jukka (National Academy of Sciences, 2021)
    Proceedings of the National Academy of Sciences Sep 2021, 118 (36) e2102798118
    The speed and uncertainty of environmental change in the Anthropocene challenge the capacity of coevolving social–ecological–technological systems (SETs) to adapt or transform to these changes. Formal government and legal structures further constrain the adaptive capacity of our SETs. However, new, self-organized forms of adaptive governance are emerging at multiple scales in natural resource-based SETs. Adaptive governance involves the private and public sectors as well as formal and informal institutions, self-organized to fill governance gaps in the traditional roles of states. While new governance forms are emerging, they are not yet doing so rapidly enough to match the pace of environmental change. Furthermore, they do not yet possess the legitimacy or capacity needed to address disparities between the winners and losers from change. These emergent forms of adaptive governance appear to be particularly effective in managing complexity. We explore governance and SETs as coevolving complex systems, focusing on legal systems to understand the potential pathways and obstacles to equitable adaptation. We explore how governments may facilitate the emergence of adaptive governance and promote legitimacy in both the process of governance despite the involvement of nonstate actors, and its adherence to democratic values of equity and justice. To manage the contextual nature of the results of change in complex systems, we propose the establishment of long-term study initiatives for the coproduction of knowledge, to accelerate learning and synergize interactions between science and governance and to foster public science and epistemic communities dedicated to navigating transitions to more just, sustainable, and resilient futures.
  • Pietilä, Ilkka; Ojala, Hanna (2021)
    Theories of inclusive masculinity and horizontal homosociality describe how previously marginalized forms of masculinity are becoming socially acceptable. Studies within these theoretical frameworks have largely focused on privileged groups of men and men’s changing attitudes towards homosexuality. This raises questions about the extent to which the theories apply to marginalized groups of men and other inequalities between men. In this article, we analyse ethnographic data from two Finnish older men’s communities that emphasize equality between men as an essential part of their ethos, and ask how inclusive practices and horizontal homosociality operate in these communities. Our intersectional analysis shows that older men’s communities may involve varying levels of inclusive practices that do not necessarily relate to sexuality but, instead, to other aspects of inequality. Future studies should consider the contextuality of men’s practices and the intersectional differences between men that are the subjects of these inclusive or exclusionary practices.
  • Lintulaakso, Kari; Polly, P.D.; Eronen, Jussi (2019)
    Aim We use cluster analysis to delimit climatically and functionally distinct mammalian faunal clusters. These entities form regional species pools and are relevant to community assembly processes. Similar clusters can be differentiated in the fossil record, offering the potential for use as palaeoenvironmental proxies. Location North America within W178 degrees, W14 degrees, N83 degrees, N7 degrees and Europe within W32 degrees, E35 degrees, N80 degrees, N35 degrees. Major taxa studied 575 and 124 land mammal species from North America and Europe. Methods K-means clustering was used to subdivide North America and Europe into distinct faunas ranging in number from 3 (largest scale) to 21 (smallest scale). Each set of faunas was tested for significant differences in climate (mean annual precipitation, mean annual temperature) and functional traits (body mass, locomotion and diet). Results In North America, climatic differentiation exists at the scale where mammals are divided into 11 or fewer distinct faunas and, in Europe, at the scale where there are five or fewer faunas. Functional trait differentiation in body mass occurs at a larger spatial scale in North America (8 distinct faunas), but locomotor differentiation is present at all spatial scales, and dietary differentiation is not present at any scale. No significant differentiation in any functional trait at any scale was found in Europe. Main conclusions Faunal clusters can be constructed at any spatial scale, but clusters are climatically and functionally meaningful only at larger scales. Climatic (and environmental) differences and their associated functional trait specialisations are likely to be barriers to large-scale mixing. We argue, therefore, that functionally and climatically distinct faunal clusters are the entities that form regional species pools for community assembly processes. In North America, there are eight such mammal pools, but only one in Europe. Since the functional traits in our study are observable in the fossil record, functional trait analysis can potentially be used to diagnose climatically distinct regions in the past.
  • Karttunen, Marie-Louise (2000)
    Community - how it may be defined by the theorist, what it subsumes, its basis, and how it is perceived by its practitioners - is of crucial importance to the social scientist. This paper proposes to discuss these issues in relation to two expatriate Baltic British communities which, though similar in terms of voluntary diaspora, economic and social background and geographic placement, are separated by a century of time. I believe that by contrasting two such similar but different groups, the specificities of both become more salient and their placement within the theoretical discourse which concerns community less problematic. The fact of their temporal sitings brings into play the modernity/postmodernity dialectic, which, superficially, could be implemented to 'explain' differences, but which provides no explanation for continuities, nor for the process by which changes have occurred. Simply deploying terms such as coherent, integrated, metanarrative, the inviolability of the nation state and so on in analysis of communities sited in the 'era' of modernity, and seemingly inevitably oppositional terms in analysis of postmodern entities, is a course which, I argue, must be approached warily. Using primary data collected from 18 months participant observation of expat British activities in Helsinki in 1998 and 1999, and the unpublished diaries and published memoirs of active members of the St. Petersburg expatriate British community, circa 1890, I have attempted to inform theoretical perceptions of the two time frames involved via the praxis, discourse and endogenous perceptions of this similar - and connected - group situated in both eras. Naturally, and conversely, theoretical appraisals of the two eras also have an important role in informing ethnographic discussion of communities sited within them. This is not, per se, an ethnographic study of the lifestyles of the two groups involved, although some such description of the St. Petersburg community is included - both to site the group for the contemporary reader and because it is fascinating. The study is, however, a reproduction of the practical means by which community was maintained and strengthened among the St. Petersburg Brits and how it is constructed and maintained in a newer incarnation in Helsinki in the late 1990's. This has involved extracting discursive topics which appear with great regularity and conformity of deployment and understanding among contemporary Brits and those of last century - behavioural patterns, measures of group acceptability, methods of group discipline and reward and the siting of these within the communities. While only tentative 'conclusions' may be drawn on such a subject, such as I present tend towards the view that, if one gives weight to the views, perceptions, discourse and praxis of members of communities concerned, there has not been the social rupture between community praxis in the eras of 'modernity' and 'postmodernity' suggested by such as Lyotard and Bauman, despite superficially salient evidence for this.