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- Charlier, Johan
(författare)
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Spatio-temporal genetic variation in wild animal and plant populations in Sweden and its relevance for conservation genetic monitoring
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human impact on the world’s ecosystems is massive, resulting in habitat destruction and fragmentation that strongly affects the future survival of non-human life forms. Typically, biodiversity loss at the genetic level is much less recognized as compared to the levels of species and ecosystems, and information on reduction of natural gene pools is frequently missing unless coupled with loss of an entire species. To detect reductions or changes in genetic composition, genetic variation must be studied over time (genetic monitoring). Presently, monitoring is to a larger scale implemented at the ecosystem and species levels to identify biodiversity loss, whereas monitoring programs at the gene level are still missing for most species.This thesis focuses on “conservation genetic monitoring”, which I and my co-authors have defined to include identifying and safeguarding gene level biodiversity for the implementation of the Convention of Biological Diversity (CBD). Amount of genetic variation, genetic composition, and spatial genetic structure must be systematically studied over time to detect potential changes of these parameters that can reflect in loss of gene level biodiversity.Paper I of this thesis suggests categories of species for which monitoring genetic diversity appears particularly urgent on the basis of e.g. level of exploitation and threat status. We stress that a basic description of a species´ spatial distribution of genetic variation at some point in time represents a primary prerequisite for future monitoring. Therefore, literature searches were conducted to collect information on the current knowledge regarding spatio-temporal genetic variation in wild animal and plant populations in Sweden. Basic starting points for “conservation genetic monitoring” of Swedish species is fairly limited. A total of 775 scientific studies including genetic information for a total of 374 species were found, but most of them (277) were directed towards only a few species of bony fishes and forest trees. Only four percent of the studies also included temporally spaced samples. For several species for which conservation genetic monitoring is considered particularly urgent genetic data is missing. One such species is the moose (Alces alces), the demography of which is almost completely controlled by man. Various moose hunting strategies are expected to directly affect the genetically effective population size and generation interval, factors that govern the rate of loss of genetic variation. These potential effects are insufficiently recognized among managers, and genetic data is largely missing for this ecologically and socio-economically important mammal. Paper II focuses on the generation of basic information on the spatial genetic structure of the Swedish moose population using six microsatellite loci. The results indicate that the moose in Sweden does not constitute a single panmictic unit, and there are indications of a local bottleneck in one area. For an evolutionary sustainable management of the moose, it is important that management and genetic groupings coincide.
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| 2. |
- Andersson, Mathias H., 1976-
(författare)
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Man-made structures as habitat for marine faunal assemblages
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Artificial reefs are structures placed in the sea to promote marine life. Although constructions such as oil-rigs, wind farms, bridges and pier pilings are built for other purposes, they could be regarded as artificial reefs as they add new surfaces in the oceans, susceptible to colonization by marine organism. One of the most common constructions in the oceans is cylindrical structures of different materials. Most research of artificial reefs has been conducted in tropical and temperate water and experience and conclusions cannot always be applied to colder waters. Man-made constructions are common in northern European seas, however, few studies are presented in the scientific literature on their impact on the marine ecosystem. The aim of this thesis was to study cylindrical structures of different scale and materials, in order to determine their effect on local fish, algae and sessile invertebrate assemblages. These structures were offshore wind turbines, and pillars of different materials (concrete and steel), situated at the Swedish east and west coast, respectively. They add vertical surfaces into the otherwise empty water column, increasing the probability for fish and invertebrate larvae as well as algae spores and propagules to encounter these high structures, compared to low profile natural or other artificial reefs. Fish species usually associated with rocky reefs and algae communities, i.e. the two spotted goby and the goldsinny-wrasse, showed an increase in abundance around the introduced cylindrical structures. Similar effect on fish species were found on both the Swedish east and west coast. The observed increase in fish densities seemed to be caused by added habitat since the pillars and wind turbines provide shelter from predators as well as increased food availability. The latter was either due to the fouling assemblage or change in water movement. The environment created by the introduced structures functions both as nursery and spawning areas since juveniles, adults and gravid fish were recorded in close association with the structures. The fouling community on the vertical surfaces did not resemble the natural assemblages and a difference in recruitment and succession on the pillars of different materials were observed. Further, dissimilar fouling assemblages were observed with other species dominating the assemblages on a fifty year old light-house foundation compared to the seven year old wind turbines, both located in the same area. The sessile filter feeding invertebrates located on the foundations have an advantage in food accessibility towards individuals at the seabed, as the organisms on the foundations are constantly susceptible to the water passing by. In addition, by adding offshore structures in areas previously lacking hard surfaces, non-indigenous species could find new available habitat or the foundations can function as stepping stones into new geographical regions.
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