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You searched for +publisher:"University of Oulu" +contributor:("Heino, J."). Showing records 1 – 3 of 3 total matches.

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University of Oulu

1. Grönroos, M. (Mira). Metacommunity structuring in stream systems:disentangling the roles of regional and local processes.

Degree: 2015, University of Oulu

Abstract Knowing which factors govern variation in community structure is crucial for assessing and conserving biodiversity. Two main processes structuring biological communities are selection by environmental conditions and dispersal between sites. In this thesis, I studied the potential importance of these two processes in structuring stream metacommunities (i.e. a set of local communities that are connected by the dispersal of individuals). I used altogether four datasets collected from three different drainage basins located in northern Finland. For small species, such as stream diatoms, bryophytes and macroinvertebrates, measuring dispersal directly and for all the species in a community, is very difficult. Thus, I used three kinds of spatial proxies to represent the potential effects of dispersal: (1) the size of species pool, (2) spatial locations of the sample sites and (3) distances between sites. In general, local environmental characteristics explained the variation in community structure better than any of the spatial proxies. The results suggested that stream diatoms, bryophytes and macroinvertebrates should not be dispersal limited at within-basin scale. However, in some cases spatial proxies explained a relatively larger proportion of community variation. One major difficulty when using such proxies is that high and limiting dispersal rates produce similar patterns. Here, I also present and test a novel hierarchical metacommunity approach for differentiating if a significant spatial signal is produced by high or limiting dispersal rates. This approach seemed promising. The results suggested that, at very small spatial scales (i.e. within a stream section) the community composition of stream macroinvertebrates is possibly influenced by high dispersal rates. I also used the so-called deconstructive approach and assigned the whole community into smaller groups of species based on their traits (i.e. feeding mode, dispersal mode and body size). This approach showed, for example, that metacommunity organization of species with actively dispersing terrestrial adults was, in general, more strongly related to environmental variables than the metacommunity organization of more passively dispersing species. I conclude that several approaches are needed for disentangling the importance of dispersal at the metacommunity level.

Tiivistelmä Eliöyhteisöjen rakenteeseen vaikuttavien tekijöiden tunteminen on välttämätöntä luonnon monimuotoisuuden hoidon ja suojelun kannalta. Kaksi merkittävää tekijää yhteisörakenteen säätelyssä ovat ympäristötekijöiden aiheuttama valinta ja levittäytyminen. Tutkin väitöskirjassani näiden kahden tekijän suhteellista merkitystä puroeliöiden metayhteisöjen rakentumiselle. Metayhteisöllä tarkoitetaan joukkoa paikallisia yhteisöjä, joiden välillä yksilöt kykenevät levittäytymään. Käytin neljää aineistoa, jotka oli kerätty yhteensä kolmelta valuma-alueelta Pohjois-Suomesta. Pienille lajeille, kuten piileville, sammalille ja pohjaeläimille, levittäytymisen mittaaminen suoraan ja kaikille…

Advisors/Committee Members: Heino, J. (Jani), Muotka, T. (Timo).

Subjects/Keywords: aquatic bryophytes; benthic macroinvertebrates; boreal streams; community structure; deconstructive approach; diatoms; dispersal; environmental selection; spatial scale; species richness; borealliset latvapurot; lajiominaisuus; lajirunsaus; levittäytyminen; piilevät; pohjaeläimet; spatiaalinen mittakaava; vesisammalet; yhteisörakenne; ympäristöfiltteri

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APA (6th Edition):

Grönroos, M. (. (2015). Metacommunity structuring in stream systems:disentangling the roles of regional and local processes. (Doctoral Dissertation). University of Oulu. Retrieved from http://urn.fi/urn:isbn:9789526209562

Chicago Manual of Style (16th Edition):

Grönroos, M (Mira). “Metacommunity structuring in stream systems:disentangling the roles of regional and local processes.” 2015. Doctoral Dissertation, University of Oulu. Accessed January 21, 2019. http://urn.fi/urn:isbn:9789526209562.

MLA Handbook (7th Edition):

Grönroos, M (Mira). “Metacommunity structuring in stream systems:disentangling the roles of regional and local processes.” 2015. Web. 21 Jan 2019.

Vancouver:

Grönroos M(. Metacommunity structuring in stream systems:disentangling the roles of regional and local processes. [Internet] [Doctoral dissertation]. University of Oulu; 2015. [cited 2019 Jan 21]. Available from: http://urn.fi/urn:isbn:9789526209562.

Council of Science Editors:

Grönroos M(. Metacommunity structuring in stream systems:disentangling the roles of regional and local processes. [Doctoral Dissertation]. University of Oulu; 2015. Available from: http://urn.fi/urn:isbn:9789526209562


University of Oulu

2. Vilmi, A. (Annika). Assessing freshwater biodiversity:insights from different spatial contexts, taxonomic groups and response metrics.

Degree: 2017, University of Oulu

Abstract Freshwater ecosystems are severely threatened by a variety of anthropogenic stressors. In order to keep track with at least part of the changes, it is important to efficiently assess and monitor freshwater biological diversity. Biological assessment programs are developed to detect human-induced changes in the ecological state of aquatic systems. These programs typically rely on the assumption that environmental conditions are the sole drivers of biological communities occupying a site and, thus, these local communities would correctly inform about environmental conditions. Recently, this background principle of current bioassessment methods has faced some criticism, stemming from the idea that community structuring is a more complex process than just a mere result of local environmental conditions. In this thesis, I studied the natural and anthropogenic drivers of freshwater biodiversity. I was particularly interested if the various biodiversity metrics studied showed any spatial patterns and if so, for which reasons these patterns might occur. To obtain a comprehensive picture of spatial patterns in biodiversity, I studied multiple spatial contexts, biological groups and indices. I found that environmental conditions were not the only drivers of freshwater biodiversity. Instead, different spatial patterns, likely stemming from dispersal processes, were surprisingly powerful drivers of aquatic communities and index values derived from them. The spatial context (i.e. spatial extent and connectivity) of the aquatic study systems likely played a major role in structuring biodiversity. I also found that the distinct biological groups and indices studied were partly related to different predictor variables. The findings of this thesis are of importance to the development of new bioassessment methods. The results of this thesis also suggest that the spatial context of the study setting should be acknowledged when interpreting results based on current bioassessment methods.

Tiivistelmä Makeanveden ekosysteemit ovat hyvin alttiita ihmistoiminnalle. Ekosysteemissä mahdollisesti tapahtuvien muutosten havaitseminen vaatii tehokkaita vesistöjen ekologisen tilan ja luonnon monimuotoisuuden arviointi- ja seurantamenetelmiä. Näiden menetelmien toimintaperiaatteen yleisenä tausta-ajatuksena on, että biologiset yhteisöt määräytyvät paikallisten ympäristöolojen mukaan. Tietyn paikan yhteisön oletetaan siis heijastavan kyseisen paikan ympäristön tilaa. Viime aikoina tausta-ajatus paikallisten ympäristöolojen merkityksestä ainoana eliöyhteisöjä muovaavana tekijänä on kuitenkin kohdannut kritiikkiä. Kriitikot painottavat, että biologisten yhteisöjen rakenteeseen vaikuttavat monet muutkin asiat kuin paikalliset ympäristöolosuhteet ja niissä tapahtuvat ihmisperäiset muutokset. Väitöskirjassani tutkin sisävesien luonnon monimuotoisuuteen vaikuttavia tekijöitä. Olin erityisen kiinnostunut siitä, näkyykö tutkituissa biologisissa parametreissa maantieteellisessä tilassa ilmeneviä spatiaalisia säännönmukaisuuksia. Saadakseni…

Advisors/Committee Members: Heino, J. (Jani), Karjalainen, S. (Satu Maaria), Oksanen, J. (Jari).

Subjects/Keywords: aquatic ecosystems; bacteria; biodiversity; biological monitoring; community structure; diatoms; dispersal; ecological indicators; macroinvertebrates; macrophytes; mass effects; metacommunities; spatial patterns; bakteerit; biologinen seuranta; dispersaali; ekologiset indikaattorit; luonnon monimuotoisuus; metayhteisöt; piilevät; pohjaeläimet; spatiaaliset säännönmukaisuudet; vesiekosysteemit; vesikasvit; yhteisörakenne

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APA (6th Edition):

Vilmi, A. (. (2017). Assessing freshwater biodiversity:insights from different spatial contexts, taxonomic groups and response metrics. (Doctoral Dissertation). University of Oulu. Retrieved from http://urn.fi/urn:isbn:9789526216669

Chicago Manual of Style (16th Edition):

Vilmi, A (Annika). “Assessing freshwater biodiversity:insights from different spatial contexts, taxonomic groups and response metrics.” 2017. Doctoral Dissertation, University of Oulu. Accessed January 21, 2019. http://urn.fi/urn:isbn:9789526216669.

MLA Handbook (7th Edition):

Vilmi, A (Annika). “Assessing freshwater biodiversity:insights from different spatial contexts, taxonomic groups and response metrics.” 2017. Web. 21 Jan 2019.

Vancouver:

Vilmi A(. Assessing freshwater biodiversity:insights from different spatial contexts, taxonomic groups and response metrics. [Internet] [Doctoral dissertation]. University of Oulu; 2017. [cited 2019 Jan 21]. Available from: http://urn.fi/urn:isbn:9789526216669.

Council of Science Editors:

Vilmi A(. Assessing freshwater biodiversity:insights from different spatial contexts, taxonomic groups and response metrics. [Doctoral Dissertation]. University of Oulu; 2017. Available from: http://urn.fi/urn:isbn:9789526216669

3. Tolonen, K. (Katri). Taxonomic and functional organization of macroinvertebrate communities in subarctic streams.

Degree: 2018, University of Oulu

Abstract Ecological research based on both species and their traits help us to understand the main mechanisms and environmental factors structuring biological communities. In general, variation in community composition is thought to be a consequence of both stochastic and deterministic factors. In stream ecology, the traditional view has been that the local habitat conditions pose a strong environmental filter that selects only species with the right functional traits into the local communities. However, recent studies on streams have also suggested that the responses of species to environmental gradients may be independent of those of other species due to stochastic factors, such as species dispersal, which then result in more continuous communities along environmental gradients. The aim of this thesis was to explore the relative importance of the deterministic and stochastic factors in the structuring of taxonomic and functional trait-based macroinvertebrate communities in streams in a high-latitude catchment by comparing the variation in these community facets along environmental and spatial gradients. Also, the relationship between environment and the functionally-defined communities was explored closely. The results indicated how the taxonomic composition of the communities may be more closely related to the stochastic and dispersal-related factors, whereas the functional composition of the communities may be more closely related to the deterministic environmental filtering processes. However, the overall structure of the communities seems to be strongly controlled by the variation in environment, although the heterogeneous and harsh conditions of the streams may preclude the formation of predictable community types. Nonetheless, some noticeable responses of different traits to different environmental factors were found, suggesting that definable functional trait-environment relationships may be discovered if key traits of the species can be identified. Overall, these findings underline the benefits of describing both taxonomic and functional-based communities when exploring the mechanisms behind the structuring of macroinvertebrate communities. The results also have applications for conservation practices. Conservation efforts should focus on varying environmental conditions in order to cover all aspects of macroinvertebrate community variation.

Tiivistelmä Lajeihin ja lajien toiminnallisiin lajiominaisuuksiin pohjautuva ekologinen tutkimus tuo uutta tietoa biologisten yhteisöjen taustalla vaikuttavista tekijöistä. Yleisesti yhteisöjen rakentumiseen vaikuttavat niin deterministiset kuin stokastiset ympäristössä vaikuttavat tekijät. Virtavesiyhteisöjen on perinteisesti ajateltu rakentuneen niin sanottujen ympäristösuodattimien mukaisesti, jolloin ympäristön vaihtelu suodattaa tietynlaisiin ympäristöihin vain lajit, joilla on tarvittavat ominaisuudet paikalla selviytyäkseen. Useat viimeaikaiset tutkimukset ovat kuitenkin osoittaneet virtavesiyhteisöissä elävien lajien esiintymisen vaihtelevan ympäristössä…

Advisors/Committee Members: Heino, J. (Jani), Erkinaro, J. (Jaakko).

Subjects/Keywords: benthic macroinvertebrates; biodiversity; community composition; environmental filters; environmental variation; linear modelling; spatial variation; species traits; subarctic streams; lajiominaisuudet; lineaarinen mallinnus; luonnon monimuotoisuus; pohjaeläinyhteisöt; spatiaalinen vaihtelu; subarktiset purot; yhteisörakenne; ympäristönvaihtelu; ympäristösuodatin

…J, Kärnä O-M, Erkinaro J & Heino J (2016) Hierarchical decomposition of trait… …1032–1048. II Tolonen KE, Leinonen K, Marttila H, Erkinaro J & Heino J (2017)… …Heino J (2017) Ecological uniqueness of macroinvertebrate communities in high… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Tolonen, K. (. (2018). Taxonomic and functional organization of macroinvertebrate communities in subarctic streams. (Doctoral Dissertation). University of Oulu. Retrieved from http://urn.fi/urn:isbn:9789526217673

Chicago Manual of Style (16th Edition):

Tolonen, K (Katri). “Taxonomic and functional organization of macroinvertebrate communities in subarctic streams.” 2018. Doctoral Dissertation, University of Oulu. Accessed January 21, 2019. http://urn.fi/urn:isbn:9789526217673.

MLA Handbook (7th Edition):

Tolonen, K (Katri). “Taxonomic and functional organization of macroinvertebrate communities in subarctic streams.” 2018. Web. 21 Jan 2019.

Vancouver:

Tolonen K(. Taxonomic and functional organization of macroinvertebrate communities in subarctic streams. [Internet] [Doctoral dissertation]. University of Oulu; 2018. [cited 2019 Jan 21]. Available from: http://urn.fi/urn:isbn:9789526217673.

Council of Science Editors:

Tolonen K(. Taxonomic and functional organization of macroinvertebrate communities in subarctic streams. [Doctoral Dissertation]. University of Oulu; 2018. Available from: http://urn.fi/urn:isbn:9789526217673

.