Journal Staff

Lichens are, in most cases, sensitive to anthropogenic factors such as air pollution, global warming, forestry and fragmentation. Two studies are included in this thesis. The first is an evaluation of the importance of old oak for the rare epiphytic lichen Cliostomum corrugatum (Ach.) Fr. This study analysed whether C. corrugatum was limited by dispersal or restricted to tree stands with an unbroken continuity or the substrate old oaks. The results provide evidence that the investigated five populations in Östergötland, Sweden, of C. corrugatum exhibit substantial gene flow, an effective dispersal and a small genetic variation between the sites. Most of the genetic variation was within the populations. Thus, C. corrugatum is more dependent of the substrate old oaks, rather than limited by dispersal. The second study investigated possible range shift of some common macrolichens, due to global warming, from 64 sites in southern Sweden comparing the two years 1986 and 2003. The centroid of three lichen species had moved a significant distance, all in a north east direction: Hypogymnia physodes (L.) Nyl. and Vulpicida pinastri (Scop.) J.-E. Mattsson and M. J. Lai on the tree species Juniperus communis L. (50 and 151 km, respectively) and H. physodes on Pinus sylvestris L. (41 km). Considering also the non-significant cases, there is strong evidence for a prevailing NE direction of centroid movement

Constitutional Existence Conditions and Judicial Review

Although critics of judicial review sometimes call for making the entire Constitution nonjusticiable, many familiar norms of constitutional law state what we call existence conditions that are necessarily enforced by judicial actors charged with the responsibility of applying, and thus as a preliminary step, identifying, propositions of sub-constitutional law such as statutes. Article I, Section 7, which sets forth the procedures by which a bill becomes a law, is an example: a putative law that did not go through the Article I, Section 7 process and does not satisfy an alternative test for legal validity (such as the treaty-making provision of Article II, Section 2), has no legal existence. A judge who disclaims the power of judicial review nevertheless enforces Article I, Section 7 when he finds that a putative statute is (or is not) an enactment of Congress that he must take account of. We contrast existence conditions with application conditions that limit the legal force of a proposition of nonconstitutional law by some means other than vitiating the status of that proposition as law. For example, absent payment of just compensation, the Takings Clause would block the application of an otherwise valid statute such as the Endangered Species Act to a privately owned parcel of land if the impact of that application were to destroy all economically viable use of the parcel. Judicial enforcement of application conditions is not entailed by the enforcement of ordinary sub-constitutional law, even though judicial non-enforcement of application conditions might be unwise. After setting forth the conceptual distinction between existence and application conditions, we argue that many familiar constitutional provisions and doctrines - including the scope of enumerated powers and some individual rights - are best read as existence conditions and are thus necessarily judicially enforced. We then reconcile that observation with a variety of doctrines - including the political question doctrine, the enrolled bill doctrine, and the rational basis test - that seem to authorize the courts not to enforce or to under-enforce existence conditions. We argue that these doctrines should be understood in some instances as granting epistemic deference to non-judicial interpreters of the Constitution and in other instances as reflecting the fact that some constitutional provisions and doctrines are perspectival - that is, they have different content for different addressees

Studies on spatial and temporal distributions of epiphytic lichens

Lichens are an important group of organisms in terms of environmental issues, conservation biology and biodiversity, since lichens are sensitive to changes in their environment. Therefore it is important that we develop our understanding of the factors that affect lichen distribution. In this thesis both spatial and temporal distributions of epiphytic lichens at different scales have been studied in southern Sweden. Brokind was chosen as the study site to investigate the succession of epiphytic lichens on Quercus robur using a chronosequencial approach. Fourteen of the investigated taxa out of 50 proved to be significant. The taxa were divided into three groups according to whether they occurred on young, middle-aged or old trees. Generation length of the red-listed lichen Cliostomum corrugatum was examined using Bjärka-Säby as the study site. The results showed that the average age of an individual of C. corrugatum is 25–30 years at the onset of spore production. Generation length of the red-listed lichen Cliostomum corrugatum was examined using Bjärka-Säby as the study site. The results showed that the average age of an individual of C. corrugatum is 25–30 years at the onset of spore production. The rarity of C. corrugatum was also examined. DNA of an intron from 85 samples, collected at five sites in Östergötland, yielded 11 haplotypes. Results from the coalescent analysis, mantel test and AMOVA indicated that C. corrugatum have a high ability to disperse. The study concluded that its rarity is most likely connected with the low amount of available habitat, old Q. robur. The changes in the distribution of epiphytic lichens in southern Sweden between 1986 and 2003 were compared. For each year a centroid was calculated on all combinations of tree and lichen species. The three significant cases showed that the centroid movement pointed toward a north-east or north-north-east direction. Regional gradients of abundance and size of Hypogymnia physodes at 66 sites in southern Sweden were examined. The coordinate system rotating the reference system of investigated sites around the origin was used to search for the best explanatory power for the angle of the explanatory variables. The results showed a gradient of increase in the probability of occurrence in a north-north-east direction and an increase in diameter on thallus size in a west-north-west direction.Publication type has been changed from "Doctoral thesis, comprehensive summary" to "Report" due to withdrawal of the thesis prior to examination.</p

Description of spatial and temporal distributions of epiphytic lichens

Lichens are, in most cases, sensitive to anthropogenic factors such as air pollution, global warming, forestry and fragmentation. Two studies are included in this thesis. The first is an evaluation of the importance of old oak for the rare epiphytic lichen Cliostomum corrugatum (Ach.) Fr. This study analysed whether C. corrugatum was limited by dispersal or restricted to tree stands with an unbroken continuity or the substrate old oaks. The results provide evidence that the investigated five populations in Östergötland, Sweden, of C. corrugatum exhibit substantial gene flow, an effective dispersal and a small genetic variation between the sites. Most of the genetic variation was within the populations. Thus, C. corrugatum is more dependent of the substrate old oaks, rather than limited by dispersal. The second study investigated possible range shift of some common macrolichens, due to global warming, from 64 sites in southern Sweden comparing the two years 1986 and 2003. The centroid of three lichen species had moved a significant distance, all in a north east direction: Hypogymnia physodes (L.) Nyl. and Vulpicida pinastri (Scop.) J.-E. Mattsson and M. J. Lai on the tree species Juniperus communis L. (50 and 151 km, respectively) and H. physodes on Pinus sylvestris L. (41 km). Considering also the non-significant cases, there is strong evidence for a prevailing NE direction of centroid movement

Studies on spatial and temporal distributions of epiphytic lichens

Lichens are an important group of organisms in terms of environmental issues, conservation biology and biodiversity, since lichens are sensitive to changes in their environment. Therefore it is important that we develop our understanding of the factors that affect lichen distribution. In this thesis both spatial and temporal distributions of epiphytic lichens at different scales have been studied in southern Sweden. Brokind was chosen as the study site to investigate the succession of epiphytic lichens on Quercus robur using a chronosequencial approach. Fourteen of the investigated taxa out of 50 proved to be significant. The taxa were divided into three groups according to whether they occurred on young, middle-aged or old trees. Generation length of the red-listed lichen Cliostomum corrugatum was examined using Bjärka-Säby as the study site. The results showed that the average age of an individual of C. corrugatum is 25–30 years at the onset of spore production. Generation length of the red-listed lichen Cliostomum corrugatum was examined using Bjärka-Säby as the study site. The results showed that the average age of an individual of C. corrugatum is 25–30 years at the onset of spore production. The rarity of C. corrugatum was also examined. DNA of an intron from 85 samples, collected at five sites in Östergötland, yielded 11 haplotypes. Results from the coalescent analysis, mantel test and AMOVA indicated that C. corrugatum have a high ability to disperse. The study concluded that its rarity is most likely connected with the low amount of available habitat, old Q. robur. The changes in the distribution of epiphytic lichens in southern Sweden between 1986 and 2003 were compared. For each year a centroid was calculated on all combinations of tree and lichen species. The three significant cases showed that the centroid movement pointed toward a north-east or north-north-east direction. Regional gradients of abundance and size of Hypogymnia physodes at 66 sites in southern Sweden were examined. The coordinate system rotating the reference system of investigated sites around the origin was used to search for the best explanatory power for the angle of the explanatory variables. The results showed a gradient of increase in the probability of occurrence in a north-north-east direction and an increase in diameter on thallus size in a west-north-west direction.Publication type has been changed from "Doctoral thesis, comprehensive summary" to "Report" due to withdrawal of the thesis prior to examination.</p

Studies on spatial and temporal distributions of epiphytic lichens

Lichens are an important group of organisms in terms of environmental issues, conservation biology and biodiversity, principally due to their sensitivity to changes in their environment. Therefore it is important that we develop our understanding of the factors that affect lichen distribution. In this thesis, both spatial and temporal distributions of epiphytic lichens at different scales have been studied in southern Sweden. Generation time of the red-listed lichen Cliostomum corrugatum was examined using Bjärka-Säby as the study site. The results showed that the average age of an individual of C. corrugatum is 25–30 years at the onset of spore production. The rarity of C. corrugatum was also examined. DNA analysis of an intron from 85 samples, collected at five sites in Östergötland, yielded 11 haplotypes. Results from coalescent analysis, mantel test and AMOVA indicated that C. corrugatum have a high ability to disperse. The study concluded that its rarity is most likely connected with the low amount of available habitat, old Quercus robur. The changes in the distribution of epiphytic lichens in southern Sweden, between 1986 and 2003, were also compared. For each year a centroid was calculated on all combinations of tree and lichen species. The three significant cases showed that the centroid movement pointed toward a north-east or north-north-east direction. Finally differences in species richness and cover of lichens on large Q. robur were examined between urban and rural environment. The results demonstrated that species number and percent cover was significantly higher on oaks standing rural compared to oaks standing urban. Effects of urban sprawl showed a decline in species richness and cover with increasing age of the surrounding buildings.In the electronic version of this dissertation the Södertörn series Södertörn Doctoral Dissertation 72, ISSN 1652–7399, has been removed.</p

Description of spatial and temporal distributions of epiphytic lichens

Lichens are, in most cases, sensitive to anthropogenic factors such as air pollution, global warming, forestry and fragmentation. Two studies are included in this thesis. The first is an evaluation of the importance of old oak for the rare epiphytic lichen Cliostomum corrugatum (Ach.) Fr. This study analysed whether C. corrugatum was limited by dispersal or restricted to tree stands with an unbroken continuity or the substrate old oaks. The results provide evidence that the investigated five populations in Östergötland, Sweden, of C. corrugatum exhibit substantial gene flow, an effective dispersal and a small genetic variation between the sites. Most of the genetic variation was within the populations. Thus, C. corrugatum is more dependent of the substrate old oaks, rather than limited by dispersal. The second study investigated possible range shift of some common macrolichens, due to global warming, from 64 sites in southern Sweden comparing the two years 1986 and 2003. The centroid of three lichen species had moved a significant distance, all in a north east direction: Hypogymnia physodes (L.) Nyl. and Vulpicida pinastri (Scop.) J.-E. Mattsson and M. J. Lai on the tree species Juniperus communis L. (50 and 151 km, respectively) and H. physodes on Pinus sylvestris L. (41 km). Considering also the non-significant cases, there is strong evidence for a prevailing NE direction of centroid movement

Decline in lichen biodiversity on oak trunks due to urbanization Decline in lichen biodiversity on oak trunks due to urbanization

Abstract: Biodiversity often suffers from urbanization. In the present study, we focused on how the length of urbanization affects the richness of 17 epiphytic lichen species and their cover on large oaks in urban environments in a city of 100 000 inhabitants in SE Sweden. We also surveyed trees in adjacent rural areas, selected to have similar distributions of tree trunk circumference and surrounding oak density (within 300 m). Lichen richness and cover were lower on urban trees compared to rural trees. Furthermore, richness and cover decreased with the length of time that urban trees had been surrounded by houses. Most of the species that were analysed demonstrated a decline in occurrence with respect to the duration of housing development. The reduction in the probability of occurrence varied from 60% (Calicium viride, Evernia prunastri), 80% (Chrysothrix candelaris) to 90% (Ramalina spp. Ach.) during the 160-year period of urbanization considered. Therefore, even if valuable trees survive over the course of development, their lichen biota is likely to become depleted over time

Decline in lichen biodiversity on oak trunks due to urbanization

Biodiversity often suff ers from urbanization. In the present study, we focused on how the duration of urbanization aff ects therichness of 17 epiphytic lichen species and their cover on large oaks in urban environments in a city of 100 000 inhabitantsin southeast Sweden. We also surveyed trees in adjacent rural areas, selected to have similar distributions of tree trunkcircumference and surrounding oak density (within 300 m). Lichen richness and cover were lower on urban trees comparedto rural trees. Furthermore, richness and cover decreased with the length of time that urban trees had been surrounded byhouses. Most of the species that were analysed demonstrated a decline in occurrence with respect to the duration of housingdevelopment. Th e reduction in the probability of occurrence varied from 60% ( Calicium viride , Evernia prunastri ), 80%( Chrysothrix candelaris ) to 90% ( Ramalina spp.) during the considered 160-year period of urbanization. Th erefore, even ifvaluable trees survive over the course of development, their lichen biota is likely to become depleted over time