Species diversity in a changing landscape
Martin Sykes (project leader)
Summary of results with list of publications from Lund University
Email: martin.sykes@nateko.lu.se
Adam and Eve must be allowed to live.
Meadows and semi-natural grassland in traditionally managed landscapes are characterised by high species diversity. In Europe, rationalisation in agriculture is continuing to cause extensive loss of these grassland environments. Development of strategies for the preservation and restoration of cultivated landscapes requires a broader view of the factors that govern diversity. Many theories and models are used to explain the co-existence of different species and the way diversity in plant communities is retained. Fragmentation of habitats can jeopardize species diversity, e.g. through the extinction or isolation of local populations. It is only in recent years that the importance of historical factors has been emphasised.
This interdisciplinary project focuses on a landscape in Öland that is characterised by a mosaic of cultivation. Historical information on the landscape structure over the past 300 years has been collected in a GIS map database for the area. The relationship between the present species diversity, connectivity of habitats and spatial properties in both the historical and present landscapes have been investigated.
The results show the importance of studying different aspects of species diversity in time and space. The simultaneous occurrence of different species and species diversity are affected by different processes at different scales. The size and heterogeneity of the habitat, the connectivity of grassland and historical human land use influence the patterns of diversity. At finer scales, factors such as the intensity of management appear important. It is however only the fine scale species diversity that shows a relationship with present spatial contact in the grassland, which indicates that fine scale diversity is more sensitive than coarse scale diversity to the fragmentation of habitats.
Population dynamics of annual meadow plants from local to regional scale
Katariina Kiviniemi Birgersson (project leader)
Summary of results with list of publications from Plant Ecology, Stockholm University
Email: katariina.kiviniemi@botan.su.se
The large scale diminution of semi-natural grasslands is a manifest example of a dramatic landscape change over a relatively short period. These unfertilised soils house a large number of plants, among them many that are threatened species. There is great interest in preserving the species richness which represents remnants of a cultivated landscape that has its roots as far back as the iron age. Semi-natural grasslands are also of interest for research in habitat fragmentation that varies in size and isolation. The objective of the project has been to contribute to the generalisations concerning the population dynamics of short-lived grassland species, especially at a larger spatial scale. In contrast to long-lived plants, the populations of short-lived plants are characterised by rapid dynamics, and may therefore be expected to react more quickly to any fragmentation effects. Knowledge of how plant populations are affected by local conditions or landscape changes are of interest both in an ecological context and for the solution of conservation problems.
Hybridization in time and space: conservation biology and plant evolution
Honor C. Prentice (project leader)
Summary of results from Lund University
Email: Honor_C.Prentice@ekol.lu.se
Plant hybridization poses problems for nature conservation and agriculture, and may represent a threat to rare species as well as leading to the transfer of genes from cultivated crops to their wild relatives. In order to deal with these problems, and to assess the risks associated with the spread of genetically modified crops, we need a better understanding of how and when genes are transferred between hybridizing species. However, hybridization does not only represent a problem. On a longer time scale, it has probably played an important role in plant evolution and speciation. The repeated episodes of environmental change associated with ice ages have meant that species have been repeatedly brought into contact with each other, isolated from one another and brought into renewed contact. Repeated range-changes should have provided increased opportunities for hybridization. So far, however, there have been few studies that have explored the roles of range-changes and ancient hybridization in plant evolution and speciation.
The project’s aim was to investigate hybridization and gene flow in the closely related and interfertile species-pair Silene vulgaris and S. uniflora (the bladder campion and the sea campion) and their subspecies.
Surveys of variation in nuclear markers (allozymes), chloroplast DNA and seed morphology were carried out on nearly 200 populations of the campions throughout their European distributions. Both nuclear and chloroplast markers revealed that the species must have hybridized extensively with each other in the past – during the postglacial period as they migrated northwards through Europe but also during earlier periods. The two species appear to have had largely separate immigration routes after the last ice age, but there is also evidence that modern hybridization has led to some interspecific transfer of genetic material.
The “alvar campion” is a unique subspecies of the sea campion (S. uniflora ssp. petraea) that is only found in alvar habitats on Öland and Gotland (it is endemic to these two Swedish islands). The alvar habitats are rich in calcium, open, and subject to extreme droughts, flooding and frost disturbance. Earlier studies revealed that the bladder campion (an introduced weed) hybridizes with the endemic alvar campion. Nevertheless, the alvar campion has not been genetically assimilated by the bladder campion – in contrast to the situation that often arises when invasive species are brought into contact with and hybridize with their rare relatives. Experimental crosses were carried out to investigate whether there are genetic barriers that might limit gene flow between these two hybridizing species. The germination characteristics of hybrid seed were mainly determined by the individual that was used as the pollen-donor (father) in the cross. Seed that is produced by the alvar campion – but has the bladder campion as the father – is expected to have difficulty establishing in the extreme and unpredictable alvar habitat. Conversely, bladder campion seed that is fathered by the alvar campion is likely to fail to germinate and establish in the weedy habitat of the mother plant. This “paternal effect” is predicted to act as a strong barrier to gene flow between the bladder and alvar campions.
Functional genomics of starch and grain quality
Christer Jansson (project leader)
Summary of results with list of publications
Email: Christer.Jansson@vbsg.slu.se
Starch is the second most abundant polymer on earth after cellulose. Starch is a mixture of two sugar molecules, amylose and amylopectin, and is produced by plants as energy for e.g. germinating seeds in cereals such as barley, wheat, maize and rice. For both humans and animals, starch in our crops constitutes the primary source of energy. Starch is in addition used for a large number of applications inside and outside the food industry as thickener and fat substitute in foods and in raw materials for the production of bioplastics.
The project is part of a Nordic multidisciplinary programme, and its objective has been to enhance understanding of starch synthesis and its genetic regulation in crops.
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