umu.sePublications
Change search
ReferencesLink to record
Permanent link

Direct link
Bryophyte community assembly on young land uplift islands – dispersal and habitat filtering assessed using species traits
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. (Landskapsekologi)
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. (Landskapsekologi)
Artdatabanken, Sverige Lantbruksuniversitet, Uppsala.
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. (Landskapsekologi)
Show others and affiliations
(English)Manuscript (preprint) (Other academic)
Abstract [en]

The combined challenges from rapid landscape transformations and climate change have actualize the need to understand community assembly processes in order to efficiently conserve threatened species in changing landscapes. In this study we focus on community assembly in bryophytes and use species traits to examine habitat filtering and dispersal limitation during colonization of islands recently created by land uplift processes in the Bothnian bay in northern Europe. The bryophyte floras of 20 islands differing in age, area, connectivity and habitat composition were assessed through field inventories and we compiled information across several sources to create a list of all species in the regional species pool. Data on traits related to habitat affiliations (substrate, light, moisture and pH) and dispersal/colonization ability (e.g regional abundance, spore size, sporophyte frequency) were collected and, for 420 species (94% of the regional pool) with available data, we used multivariate models to compare trait effects on species occurrence probabilities across the 20 islands. We found that occurrence probabilities depended strongly on the availability of different habitats across the islands and that regionally rare species and predominantly asexual species had sharply reduced probabilities of being present on islands compared to regionally abundant and /or sexual species, Having specialized asexual propagules had a positive effect on occurrence probabilities, but compensated only partly for the reductions in asexual species. No effects of spore size were detected. A comparison of trait effects on occurrence probabilities across island connectivity and area gradients, revealed reduced habitat filtering on larger islands and that the negative effects on occurrence probabilities in the asexual species decreased with island connectivity. An absence of connectivity relationships for sexual species, suggest that their colonization is regulated by habitat availability and the contributions of each species landscape level spore output to a “regional spore rain” from which species recruited. Conservation strategies, aimed at conserving and increasing the frequency of regional propagule sources, irrespective of their spatial configuration, could therefore be useful in this group. For asexual species, our results instead suggest a strategy aimed at spatially concentrating the conservation and restoration of habitats in order to increase metapopulation persistence.

National Category
Ecology
Research subject
Ecological Botany; Conservation Biology
Identifiers
URN: urn:nbn:se:umu:diva-121236OAI: oai:DiVA.org:umu-121236DiVA: diva2:932304
Funder
Swedish Research Council Formas, 215-2010-998
Available from: 2016-06-01 Created: 2016-05-30 Last updated: 2016-06-01
In thesis
1. Island biogeography of young land uplift islands - viewed through the lens of bryophytes in a northern Swedish archipelago
Open this publication in new window or tab >>Island biogeography of young land uplift islands - viewed through the lens of bryophytes in a northern Swedish archipelago
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Öbiogeografi hos unga landhöjningsöar - betraktad ur ett mossperspektiv.
Abstract [en]

Increasing habitat fragmentation and rapid global warming is changing the conditions for species populations and ecological communities around the world. This presents challenges for the maintenance of biodiversity and a dominant paradigm for conservation in fragmented habitats is given by island biogeography and metapopulation (or metacommunity) ecology.

In this thesis I approach key concepts (area, connectivity and community assembly) in island biogeography and metacommunity ecology within the context of a dynamic land uplift archipelago. The presented work consists of two interwoven themes: (i) A methodological theme in which statistical approaches are developed to deal with the complexities of multispecies dynamic systems, and (ii) an applied theme dealing with community assembly and island biogeography of bryophytes on young land uplift islands.

To describe island connectivity for entire species assemblages, an approach using functional principal component analysis (fPCA) on patch connectivity functions (the connectivity of an island as a continuous function of a variable representing the spatial scale of species dispersal capacities) was developed. In addition, a new statistical method, functional co-inertia analysis (fCoIA), for analyzing co-variation between multivariate species data and continuous functions was developed and applied to the relation between bryophyte species incidences and the island age/area-dynamics.

Primarily asexual bryophyte species are dispersal limited and presence probabilities are related to island connectivity. No such patterns were found for species, at least occasionally, producing spores. Our results suggest that bryophyte dispersal is regulated by the contribution of spores to a regional spore rain and that bryophyte species with low spore output at the landscape level may be extra vulnerable under habitat fragmentation and loss. Having specialized asexual propagules increases the presence probabilities on islands, partly compensating for the dispersal limitation in asexual species. This suggests a trade-off between dispersal and establishment capacity, but also points to the importance of local dispersal for maintaining populations under the succession driven spatial turnover of microsites on the islands. Bryophyte colonization is strongly limited by habitat availability when a given habitats is rare, but there seems to exist a threshold over which other processes (e.g. dispersal limitation) become more important. Species with more vagile life history strategies appear to be stronger affected by the area of available habitats than many perennial species

Place, publisher, year, edition, pages
Umeå: Umeå University, 2016. 59 p.
Keyword
functional data analysis, metacommunity, isolation, mosses, liverworts, sporophyte production, dispersal-establishment trade-off
National Category
Ecology Botany Probability Theory and Statistics
Research subject
Ecological Botany; Conservation Biology; Statistics
Identifiers
urn:nbn:se:umu:diva-121239 (URN)978-91-7601-495-0 (ISBN)
Public defence
2016-09-23, Björken, Sveriges Lantbruksuniversitet, Umeå, 09:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council Formas, 215-2010-998
Available from: 2016-06-03 Created: 2016-05-30 Last updated: 2016-06-17Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Karlsson Tiselius, AndreasJansson, RolandDynesius, Mats
By organisation
Department of Ecology and Environmental Sciences
Ecology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 116 hits
ReferencesLink to record
Permanent link

Direct link