| 1. |
- Ferreira, João G., et al.
(författare)
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Physical and biological control of fucoid recruitment in range edge and range centre populations
- 2015
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 518, s. 85-94
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Tidskriftsartikel (refereegranskat)abstract
- The structure of rocky shore assemblages is determined to a large extent by the interaction between abiotic and biotic processes. Understanding of the strength and interactive nature of these processes over different spatial and temporal scales provides insight into key structuring mechanisms and clarifies what sets species' distributions. Here we examine the potential interactive effect of physical environment (insolation stress) and grazing pressure on recruitment success of fucoid species (Fucus spp.) in North Wales and Portugal, in order to understand patterns of distribution at the centre and equatorward edge of their range. Contrary to expectations, amelioration of the physical environment through reduction of insolation stress did not improve recruitment in either geographical region. Grazing activity of patellid limpets was found to be an important process regulating fucoid recruitment only on northern European shores. The top-down control of fucoid recruitment at the northern latitude was apparent, even at half the normal densities of patellid limpets. The use of reduced light levels and reduced grazing pressure in southern regions was expected to improve fucoid recruitment, but results indicate amelioration of physical and biological pressures cannot compensate for an inherently low supply of propagules. Our study confirms that strong top-down control by grazers (Patella spp.) can directly determine the distribution and abundance of fucoid algae in core areas of its range, but toward the range edge factors other than those examined are responsible for low recruitment and, ultimately, the observed decline in fucoid abundance in southern European regions.
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| 2. |
- Hawkins, Stephen J., et al.
(författare)
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The Intertidal Zone of the North-East Atlantic Region
- 2019
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Ingår i: Interactions in the Marine Benthos: Global Patterns and Processes (Systematics Association Special Volume Series, pp. 7-46). - : Cambridge university press. - 9781108416085
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Bokkapitel (refereegranskat)abstract
- The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
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| 3. |
- Lang, Daniel, et al.
(författare)
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The Physcomitrella patens chromosome-scale assembly reveals moss genome structure and evolution
- 2018
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Ingår i: The Plant Journal. - : Wiley. - 0960-7412 .- 1365-313X. ; 93:3, s. 515-533
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Tidskriftsartikel (refereegranskat)abstract
- The draft genome of the moss model, Physcomitrella patens, comprised approximately 2000 unordered scaffolds. In order to enable analyses of genome structure and evolution we generated a chromosome-scale genome assembly using genetic linkage as well as (end) sequencing of long DNA fragments. We find that 57% of the genome comprises transposable elements (TEs), some of which may be actively transposing during the life cycle. Unlike in flowering plant genomes, gene-and TE-rich regions show an overall even distribution along the chromosomes. However, the chromosomes are mono-centric with peaks of a class of Copia elements potentially coinciding with centromeres. Gene body methylation is evident in 5.7% of the protein-coding genes, typically coinciding with low GC and low expression. Some giant virus insertions are transcriptionally active and might protect gametes from viral infection via siRNA mediated silencing. Structure-based detection methods show that the genome evolved via two rounds of whole genome duplications (WGDs), apparently common in mosses but not in liverworts and hornworts. Several hundred genes are present in colinear regions conserved since the last common ancestor of plants. These syntenic regions are enriched for functions related to plant-specific cell growth and tissue organization. The P. patens genome lacks the TE-rich pericentromeric and gene-rich distal regions typical for most flowering plant genomes. More non-seed plant genomes are needed to unravel how plant genomes evolve, and to understand whether the P. patens genome structure is typical for mosses or bryophytes.
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