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Exploring Connectivity across Spatial Scales Using Functional Principal Component Analysis
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)
(English)Article in journal (Refereed) Submitted
Abstract [en]

The interplay between organism dispersal and habitat patch connectivity is crucial for the distribution and dynamics of populations and communities. However, the appropriate spatial scales of connectivity analysis vary among species, populations and individuals, depending on their capacity and propensity to move. This scale dependence poses problems when studying assemblages including species with different appropriate scales or when the scale for a species varies or is difficult to determine. To address these problems, we develop an approach summarizing among-patch variation in structural connectivity across a continuum of scales. We do this by first treating a connectivity metric (e.g. habitat area around a patch) as a continuous function of a scale-defining variable (e.g. distance) for a number of patches. We then extract and summarize information present in the shapes of the resulting collection of “patch connectivity functions”, using methods for functional data analysis (functional principal component analysis, fPCA). We apply the approach to a data set of 36 islands and show that it is possible to effectively summarize the among-patch variation in structural patch connectivity across spatial scales using only a small number of functional principal components. We also show how our functional data analysis approach to connectivity metrics can be useful (i) as an information tool for decisions regarding the design of protected area networks and (ii) in designing spatially explicit ecological studies including multiple species (e.g. metacommunity studies). We explore relationships with widely used methods in landscape ecology and show how continuous function representations can reveal information hidden in single value applications of metrics. The usefulness of the approach for analyses of functional connectivity is discussed. We conclude that the approach provides a powerful methodology to represent variation in connectivity across spatial scales that will serve many purposes within spatial ecology and biogeography

Keyword [en]
Spatial scale, Metacommunities, Metapopulations, Multispecies conservation, Functional data analysis, Functional PCA, Connectivity, Isolation, Island biogeography, Landscape context, Conservation planning, Study design
National Category
Ecology
Research subject
Conservation Biology
Identifiers
URN: urn:nbn:se:umu:diva-121232OAI: oai:DiVA.org:umu-121232DiVA: diva2:932283
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

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