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| 2. |
- Tyler, Torbjörn, et al.
(författare)
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Skånes mossor.
- 2003
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Ingår i: Floran i Skåne. Vegetation och utflyktsmål.. - 9197102148 ; , s. 117-124
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Bokkapitel (populärvet., debatt m.m.)
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| 3. |
- Tyler, Torbjörn, et al.
(författare)
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Sensitivity of the woodland herb Anemone hepatica to changing environmental conditions
- 2002
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Ingår i: Journal of Vegetation Science. - 1654-1103. ; 13:2, s. 207-216
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Tidskriftsartikel (refereegranskat)abstract
- The decline of deciduous woodland populations of Anemone hepatica L. in southern Sweden is documented and possible causes are discussed. The study was based on (1) re-investigations of 6.25 km(2) grid-squares first studied in 19381970, (2) distribution of A. hepatica in woodland sites with well-known soil chemical properties and (3) a detailed study over 12 consecutive years into the relationships between biological characteristics of the species (number of individuals, vegetative development, flowering frequency) and environmental variables (temperature, precipitation), soil chemistry and time. There was a close relationship between soil acidity (pH, solubility of Al3+) and both distribution and biological characteristics. The biological variables declined significantly overtime but were not related to climatic variability. Increasing soil acidity and Al3+ solubility are concluded to be the main factors responsible for the decline of A. hepatica in S. Swedish deciduous woodlands.
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| 4. |
- Ekman, Stefan, et al.
(författare)
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Skånes lavar
- 2003
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Ingår i: Floran i Skåne. Vegetation och utflyktsmål.. - 9197102148 ; , s. 125-132
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Bokkapitel (populärvet., debatt m.m.)
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| 5. |
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| 7. |
- Schiemann, Katarina, et al.
(författare)
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Allozyme diversity in relation to geographic distribution and population size in Lathyrus vernus (L.) Bernh. (Fabaceae)
- 2000
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Ingår i: Plant Systematics and Evolution. - 1615-6110. ; 225:1-4, s. 119-132
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Tidskriftsartikel (refereegranskat)abstract
- Lathyrus vernus (L.) Bernh. is a diploid, long-lived perennial and insect-pollinated herb with no special adaptation to long-distance dispersal. It occurs on neutral soil in deciduous forests throughout western Eurasia. Due to specific habitat preferences, L. vernus has a fragmented distribution with isolated populations. We investigated allozyme variation at eleven loci in 20 populations of L. vernus from one geographically central region (the Czech Republic and the Slovak Republic) and two geographically marginal regions (southern and central Sweden) in the species present-day distribution. There was a clear differentiation between the three regions and the genetic distance between the populations was highly correlated with geographic distance. The total genetic diversity (H-T) was 0.354. The proportion of genetic diversity due to differentiation between regions, and to differentiation between populations within regions, accounted for 10% each. There was no difference in level of genetic diversity between the three regions. No significant difference in level of genetic diversity was found between small and large populations. The genetic diversity in L. vernus may either be a result of the long generation-time of the species or peculiarities in the post-glacial migration species, e.g, survival only in refugia far east of the sampled populations and/or migration as a continuous process not involving founder-events.
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| 8. |
- Snogerup, Sven, et al.
(författare)
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Skånska vegetationstyper
- 2003
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Ingår i: Floran i Skåne. Vegetation och utflyktsmål. - 9197102148 ; , s. 53-76
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Bokkapitel (populärvet., debatt m.m.)
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| 9. |
- Tyler, Torbjörn
(författare)
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Allozyme variation in Carex sect. Digitatae - Evidence of introgression, genetic distinctiveness and evolution of taxa
- 2003
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Ingår i: Plant Systematics and Evolution. - : Springer Science and Business Media LLC. - 1615-6110 .- 0378-2697. ; 237:3-4, s. 219-231
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Tidskriftsartikel (refereegranskat)abstract
- A subset of populations of the European taxa of Carex sect. Digitatae, including Carex digitata, C. pallens, C. ornithopoda, C. pediformis ssp. rhizodes and C. humilis have been investigated for allozyme variation. The (presumably) distantly related C. pendula was used a's a reference taxon. Carex digitata, C. pallens and C. ornithopoda on the one hand, and C. humilis and C. pediformis on the other, shared the majority of the alleles. Cluster analyses based on genetic distances grouped populations of C. digitata and C. ornithopoda in a mixed subcluster whereas all populations of C. pallens formed a subcluster distinct from the digitata/ornithopoda cluster. This in spite of the fact that C. ornithopoda is morphologically clearly distinct from C. digitata whereas C. pallens is barely distinguishable from the latter. Carex pediformis and C. humilis appeared not more genetically similar to C. digitata than to the reference taxon. It is concluded that 1) C. digitata, C. pallens and C. ornithopoda are closely related and most probably forms a monophyletic group, 2) C. pallens is a genetically distinct species, 3) C. pediformis and C. humilis are not closely related to the rest of C. sect. Digitatae, 4) C. pediformis and C. humilis are relatively closely related, 5) introgression do occur between the investigated species but not to such an extent that it can explain major geographic patterns of variation in C. digitata.
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| 10. |
- Tyler, Torbjörn
(författare)
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Arter av växter: Är de och vad är de?
- 2001
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Ingår i: Nordic Journal of Botany. - 0107-055X. ; 134:1, s. 31-44
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The current confusion about what species are has two major causes. First, many authors discussing species concepts seem not to have considered for what purpose species are distinguished. Several proposed species concepts define species in a way that is only useful in a narrow field of advanced biological science. It is argued that species concepts should rather fulfil the needs of the majority of biologists who need species in order to communicate. Second, many species concepts (e.g. the biological and ecological species concepts) define species as die end products of certain specified speciation-processes, thereby confusing process and pattern and in a sense putting the cart before the horse. To facilitate unprejudiced studies of evolutionary processes it is argued that the species concept should be free from any assumptions about processes of speciation. Phylogenetic species concepts, stressing the importance of monophyly and defining species based on phylogenetic reconstructions only, are criticized for being of little use outside the field of phylogenetics. A species concept similar to Mallet's 'genotype-cluster definition', in which species are defined as groups of individuals within a discrete multi-character cluster of variation, is advocated. Whenever possible, characters should be chosen both from morphology and molecular markers, and, at least in critical taxa, the use of multivariate statistics to evaluate species distinctness is recommended. It is further argued that only those 'genotype clusters' that anyone has a practical need to distinguish should be formally recognised as taxa. In groups where many discrete genetical entities can be found, only those that are both morphologically readily distinguishable and have a unique ecology or distribution need to be recognised.
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