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- Marteinsdottir, Bryndis, 1980-
(författare)
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Assembly of plant communities in grasslands : an overview
- 2009
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- How plants are arranged into communities is one of the central questions in plant ecology. One view holds that plant assembly is governed by deterministic factors, like assembly rules, while another holds that it is mostly stochastic, only constrained by the ability of plants to disperse and survive under the current environmental conditions. Here, I summarize studies on grassland community assembly, and try to find general patterns and rules. Of the 40 reviewed studies, evidence of deterministic assembly was found in 15, while evidence for stochastic assembly was found in nine. Evidence for both factors together was found in the remaining 16 studies. The studies varied in their use of methods, measured variables and scale, making them hard to compare. Even within a single study, results were dependent on the factors mentioned above. Plant community assembly of grasslands is a complex process, affected by assembly rules, environmental filtering and stochastic factors (e.g. dispersal limitation and priority effects) and which factor has the most influence seems to be site specific. More detailed and coordinated research is needed to determine what controls community assembly in grasslands.
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| 2. |
- Marteinsdóttir, Bryndís, 1980-
(författare)
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Plant community assembly in grazed grasslands
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Species assembly into local communities from the surrounding region can be caused either by species failure to reach the site (i.e. seed limitation) or to establish (i.e. establishment limitation). The aim of this thesis was to investigate plant species assembly and to determine the relative importance of different factors in that process.In a cultivated landscape in southeast Sweden, plant community assembly was studied in grazed ex-arable fields. Community assembly from the surrounding region into the local community was explored using trait-based null models and seed sowing and transplanting experiments. The influence of local environmental factors and landscape history and structure on community assembly was also studied. In addition, differences in species assembly between ex-arable fields and semi-natural grasslands were explored.Seed limitation was the strongest filter on local community assembly. Only a fraction (36%) of species in a region dispersed to a local site and adding seeds/transplants increased species establishment. Species abundance at the regional scale, species dispersal method and seed mass strongly influenced which species arrived at the local sites. Establishment limitation also affected the assembly. Of species arriving at a site 78% did establish, seedling survival was low and which species established was influenced by species interactions, local environmental conditions and stochastic events. In addition, landscape structure that determined the species richness in the regional species pool influenced the local assembly. The comparison between assembly in ex-arable fields and semi-natural grasslands indicated that the main cause of difference in species assembly between them was difference in their age.The main conclusion of this thesis is that regional processes are more important than local factors in determining plant community assembly.
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| 3. |
- Marteinsdottir, Bryndis, 1980-, et al.
(författare)
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Plant community assembly in semi-natural grasslands and ex-arable fields : a trait-based approach
- 2014
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 25:1, s. 77-87
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Tidskriftsartikel (refereegranskat)abstract
- QuestionThe assembly of plants into communities is one of the central topics in plant community ecology. The objective of this study was to investigate how plant functional trait diversity and environmental factors influence community assembly in two different grassland communities, and if variation in these factors could explain the difference in species assembly between these communities. LocationSix grazed ex-arable fields and eight semi-natural grasslands in southeast Sweden. MethodsWe estimated species abundance and measured soil attributes at each site. For each species within each site we measured specific leaf area (SLA), leaf dry matter content (LDMC) and seed mass. We analysed the data both for abundance-weighted species values and species occurrence. ResultsTrait gradient analysis indicated random distribution of species among sites, while CCA analysis indicated that both soil phosphorus and moisture were related to species assembly at a site. Correlations and fourth-corner analysis also revealed a relationship between measured species traits and soil phosphorus and moisture. There was a lower average seed mass and higher SLA of species in ex-arable fields compared to species in semi-natural grasslands. ConclusionsEven though trait gradient analysis indicated that plant community assembly in the studied grasslands was random, other results implied that species occurrence and abundance was influenced both by environmental factors and species traits. Higher species richness in semi-natural grasslands was associated with more large-seeded species found there compared to ex-arable fields, indicating that large-seeded species establish in grasslands later than small-seeded species.
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| 4. |
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| 5. |
- Marteinsdóttir, Bryndís, 1980-, et al.
(författare)
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Trait-based filtering from the regional species pool into local grassland communities
- 2014
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Ingår i: Journal of Plant Ecology. - : Oxford University Press (OUP). - 1752-9921 .- 1752-993X. ; 7:4, s. 347-355
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Tidskriftsartikel (refereegranskat)abstract
- For plants to establish in a local community from a pool of possible colonizers from the region, it must pass through a series of filters. Which of the filters is most important in this process has been much debated. In this study, we explored how species are filtered from the regional species pool into local communities. The aim was to determine if differences in species abundance and functional traits could explain which species from the regional species pool establish at the local scale and if the filtering differed between grassland communities.This study took place in a cultivated landscape in southeastern Sweden. We estimated plant species abundance in 12 ex-arable field sites and 8 adjacent seminatural grassland sites and in a 100-m radius around the center of each site. We used Monte Carlo simulations to examine if species abundance and functional traits (height, seed mass, clonal abilities, specific leaf area and dispersal method) controlled the filtering of species from the regional pool into local communities.On average, only 28% of species found in the regional pool established in the ex-arable field sites and 45% in the seminatural grassland sites, indicating that the size of the regional species pool was not limiting local richness. For both grassland types, species abundance in the regional pool was positively correlated with species occurrence at the local scale. We found evidence for both species interaction filtering and dispersal limitation influencing the local assembly. Both local and regional processes were thus influencing the filtering of species from the regional species pool into local communities. In addition, the age of the communities influenced species filtering, indicating that community assembly and the importance of different filters in that process change over succession.
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