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1.
Changes in the forest management practices have strongly influenced the distribution of species inhabiting old-growth forests. The epiphytic woodland lichen Lobaria pulmonaria is frequently used as a model species to study the factors affecting the population biology of lichens. We sampled 252 L. pulmonaria individuals from 12 populations representing three woodland types differing in their ecological continuity and management intensity in Estonia. We used eight mycobiont-specific microsatellite loci to quantify genetic diversity among the populations. We calculated the Sørensen distance to estimate genetic dissimilarity among individuals within populations. We revealed that L. pulmonaria populations have significantly higher genetic diversity in old-growth forests than in managed forests and wooded meadows. We detected a significant woodland-type-specific pattern of genetic dissimilarity among neighbouring L. pulmonaria individuals, which suggests that in wooded meadows and managed forests dominating is vegetative reproduction. The vegetative dispersal distance between the host trees of L. pulmonaria was found to be only 15–30 m. Genetic dissimilarity among individuals was also dependent on tree species and trunk diameter. Lobaria pulmonaria populations in managed forests included less juveniles compared to old-growth forests and wooded meadows, indicating that forest management influences life stage structure within populations. We conclude that as intensive stand management reduces the genetic diversity of threatened species in woodland habitats, particular attention should be paid to the preservation of remnant populations in old-growth habitats. Within managed habitats, conservation management should target on maintenance of the stand’s structural diversity and availability of potential host trees.  相似文献   

2.
By surveying and re-surveying 12 forest sites in southern Sweden for the epiphytic lichen Lobaria pulmonaria with a 9-year interval, and measuring tree-related habitat quality variables, we have investigated whether the local distribution of the lichen is limited by poor dispersal capacity or by habitat quality. Dispersal distances were measured indirectly as the distances between colonised trees and the nearest trees occupied by L. pulmonaria in both 1992 and 2001. To compare habitat quality between trees occupied by L. pulmonaria and neighbouring control trees, we recorded tree species and measured age and growth rate of trees, light conditions, bark structure and bryophyte cover. The estimated mean dispersal distance was 35 m, with a recorded maximum of 75 m. Occupied trees were larger and had a larger cover of bryophytes than unoccupied trees of similar size. The results indicate that dispersal capacity probably is the most important factor in limiting the local distribution of L. pulmonaria, but habitat-quality factors may be important on a smaller spatial scale.  相似文献   

3.
In Italy, many lichen species rare at the national level share their ecological requirements with Lobaria pulmonaria. The aim of this work is to test this lichen as a potential indicator for assessing forest sites which are worthy of conservation for lichens in Italy. The hypothesis to be tested is that stands hosting large and viable populations of this lichen also host nationally rare and sensitive lichen species. The study was carried out in two large forested areas of Italy under different bioclimatic conditions and with different forest types: Cansiglio Forest, in NE Italy, and Cilento in SW Italy. Three types of stands characterized by different abundance levels of L. pulmonaria were identified in each site. Ten plots for each type of stand were surveyed in each site. Macrolichens were surveyed on a total of 180 trees. The abundance of L. pulmonaria proved to be a valuable indicator of forest stands hosting nationally rare lichen species and cyanolichens in different forest types and in different bioclimatic conditions. Significant differences in species richness, in the occurrence and abundance of nationally rare lichen species and cyanolichens, and in species composition were found in both sites among stands with different levels of L. pulmonaria. Results are expected to contribute to the development of more lichen-oriented criteria in nature protection policies.  相似文献   

4.
Availability of suitable trees is a primary determinant of range contractions and expansions of epiphytic species. However, switches between carrier tree species may blur co‐phylogeographic patterns. We identified glacial refugia in southeastern Europe for the tree‐colonizing lichen Lobaria pulmonaria, studied the importance of primeval forest reserves for the conservation of genetically diverse populations and analyzed differences in spatial genetic structure between primeval and managed forests with fungus‐specific microsatellite markers. Populations belonged to either of two genepools or were admixed. Gene diversity was higher in primeval than in managed forests. At small distances up to 170 m, genotype diversity was lower in managed compared with primeval forests. We found significant associations between groups of tree species and two L. pulmonaria genepools, which may indicate “hitchhiking” of L. pulmonaria on forest communities during postglacial migration. Genepool B of L. pulmonaria was associated with European Beech (Fagus sylvatica) and we can hypothesize that genepool B survived the last glaciation associated within the refuge of European Beech on the Coastal and Central Dinarides. The allelic richness of genepool A was highest in the Alps, which is the evidence for a northern refuge of L. pulmonaria. Vicariant altitudinal distributions of the two genepools suggest intraspecific ecological differentiation.  相似文献   

5.
Abstract

This study is focused on the selection of variables affecting lichen and bryophyte diversity in Mediterranean deciduous forests. Plots representing two forest types (Fagus sylvatica and Quercus cerris forests) and two forest continuity categories (old‐growth (OG) and non‐OG forests) were selected in the Cilento and Vallo di Diano National Park (Italy). The presence and the abundance of bryophytes and epiphytic lichens were recorded. Structural variables of the forests and vascular plant species richness have been used as predictors. A strong positive correspondence between the two groups of organisms was found. Higher species richness and the distribution of rare species are related to OG stands, while a qualitative (species composition) rather than a quantitative (species richness) difference between the two forest types was observed. Some species elsewhere considered as indicators of forest continuity, such as Lobaria pulmonaria, Antitrichia curtipendula, and Homalothecium sericeum, are associated with OG forests, independently from forest type, suggesting that they can be regarded as suitable indicators also in Mediterranean forests. Finally, our results suggest that old trees, high levels of basal area, a broad range of diameter classes, and high understory diversity are the main structural features affecting cryptogamic communities, while no correlation was found with the occurrence of deadwood.  相似文献   

6.
Lichenicolous fungi are a species-rich biological group growing on lichen thalli. Here, we analyze the genetic structure of the lichenicolous basidiomycete Tremella lobariacearum and three host species (Lobaria pulmonaria, Lobaria macaronesica, and Lobaria immixta) in Macaronesia. We used ordination and analysis of molecular variance to investigate the structuring of genetic variation, and a simulation test to investigate whether rDNA haplotypes of T. lobariacearum were significantly associated with host species. To investigate the evolutionary and demographic history of the lichenicolous fungus and its hosts, we used coalescent samplers to generate trees, and Bayesian skyline plots. We found that the hosts were most important in structuring populations of the lichenicolous species. Despite their wide geographic distribution, the same haplotypes of T. lobariacearum consistently associated with a given host species. Our results suggest that the Lobaria hosts create a selective environment for the lichenicolous fungus. Both the pathogen and the host populations exhibited substantial genetic structure. However, evolutionary and demographic histories differed between the parasite and its hosts, as evidenced by different divergence times and tree topologies.  相似文献   

7.
Population genetics of the tree‐colonizing lichen Lobaria pulmonaria were studied in the largest primeval beech forest of Europe, covering 10 000 ha. During an intensive survey of the area, we collected 1522 thallus fragments originating from 483 trees, which were genotyped with eight mycobiont‐ and 14 photobiont‐specific microsatellite markers. The mycobiont and photobiont of L. pulmonaria were found to consist of two distinct gene pools, which are co‐existing within small areas of 3–180 ha in a homogeneous beech forest. The small‐scale distribution pattern of the symbiotic gene pools show habitat partitioning of lineages associated with either floodplains or mountain forests. Using approximate Bayesian computation (ABC), we dated the divergence of the two fungal gene pools of L. pulmonaria as the Early Pleistocene. Both fungal gene pools survived the Pleistocene glacial cycles in the Carpathians, although possibly in climatically different refugia. Fungal diversification prior to these cycles and the selection of photobionts with different altitudinal distributions explain the current sympatric, but ecologically differentiated habitat partitioning of L. pulmonaria. In addition, the habitat preferences of the mycobiont are determined by other factors and are rather independent of those of the photobiont at the landscape level. The distinct gene pools should be considered evolutionarily significant units and deserve specific conservation priorities in the future, for example gene pool A, which is a Pliocene relict.  相似文献   

8.
Fragmentation represents a serious threat to biodiversity worldwide, however its effects on epiphytic organisms is still poorly understood. We study the effect of habitat fragmentation on the genetic population structure and diversity of the red-listed epiphytic lichen, Lobaria pulmonaria, in a Mediterranean forest landscape. We tested the relative importance of forest patch quality, matrix surrounding fragments and connectivity on the genetic variation within populations and the differentiation among them. A total of 855 thalli were sampled in 44 plots (400 m2) of 31 suitable forest fragments (beeches and oaks), in the Sierra de Ayllón in central Spain. Variables related to landscape attributes of the remnant forest patches such as size and connectivity and also the nature of the matrix or tree species had no significant effects on the genetic diversity of L. pulmonaria. Values of genetic diversity (Nei’s) were only affected by habitat quality estimated as the age patches. Most of the variation (76%) in all populations was observed at the smallest sampled unit (plots). Using multiple regression analysis, we found that habitat quality is more important in explaining the genetic structure of the L. pulmonaria populations than spatial distance. The relatively high level of genetic diversity of the species in old forest patches regardless of patch size indicates that habitat quality in a highly structured forest stand determines the population size and distribution pattern of this species and its associated lichen community. Thus, conservation programmes of Mediterranean mountain forests have to prioritize area and habitat quality of old forest patches.  相似文献   

9.
H. Reznik  E. Peveling  J. Vahl 《Planta》1968,78(3):287-292
Summary The rhizines of the lichens, Parmelia caperata, Parmelia trichotera and Lobaria pulmonaria were studied with the Stereoscan scanning electronmicroscope and in ultrathin sections with the transmission electronmicroscope. The rhizines are composed of fungal hyphae.The fungal hyphae in the rhizines of the thallus of Parmelia caperata and in the cilia at the thallus border of Parmelia trichotera are connected by a glue-like substance. The ends of the Parmelia caperata rhizines are flattened and enlarged. With these footlike rhizines the thalli are in good connection with the substratum. The cilia at the thallus border of Parmelia trichotera have a tip by which the thallus is fixed on bark or rocks. The cell walls of the fungi hyphae in the Parmelia caperata rhizines and in the Parmelia trichotera cilia are 150–400 nm thick.The rhizines of Lobaria pulmonaria consist of fungi hyphae which are interlaced without a gluey substance. The thallus of Lobaria pulmonaria is connected to the substratum through the tips of single hyphae. The hyphae walls of Lobaria pulmonaria are 800–1800 nm thick.  相似文献   

10.
Occupancy and density of the epiphytic lichen L. pulmonaria were studied in the mountains of Uholka–Shyrokyi Luh (Ukraine), which include the largest primeval beech forest in Europe. The lichen occupancy was assessed on 314 plots laid out on a systematic grid. Additional data on population density were collected from 483 trees growing both, on and between these plots. The trees harbouring L. pulmonaria were distributed very sparsely within Uholka–Shyrokyi Luh, and occupy nearly 10 % of the studied perimeter. The generalized linear models showed that area of occupancy of L. pulmonaria was significantly influenced by altitude and canopy cover, whereas the species’ density was explained by habitat types and slope exposition. Population density is higher at the timberline than in the interior forest or on lowland meadows. We found a bimodal altitudinal distribution of L. pulmonaria, with maxima below and above 900 m a.s.l., where it prefers forest stands with loose or scattered canopy. The preferred position of L. pulmonaria on host tree trunks depends on stand density and allows the species to get the necessary level of insolation also in shaded sites where it grows higher up on the trunk than in open stands. While L. pulmonaria occupied trees with various diameters, juvenile individuals are more frequent on small trees, but mature lichen individuals are predominantly found on trees of average or large sizes. Fertile individuals require specific environmental conditions, which are available at intermediate altitudes, related with sheltered light, and horizontal terraces on slopes with eastern exposition. In general, the primeval beech forest of Uholka–Shyrokyi Luh harbours a high percentage of juvenile thalli of L. pulmonaria, which lack vegetative propagules. Mature individuals have a low frequency of fruit bodies and reproduce mainly with vegetative diaspores. We interpret this as an indication of a currently growing population of L. pulmonaria within the area. We hypothesize that transboundary air pollution has decreased the lichens’ population frequency and density and has altered the ratio of developmental stages in L. pulmonaria during earlier decades.  相似文献   

11.
《Fungal biology》2020,124(10):903-913
Although water is essential for photosynthetic activation in lichens, rates of vapor uptake and activation in humid air, which likely influence their niche preferences and distribution ranges, are insufficiently known. This study simultaneously quantifies rehydration kinetics and PSII reactivation in sympatric, yet morphologically and functionally distinct cephalolichens (Lobaria amplissima, Lobaria pulmonaria, Lobaria virens). High-temporal resolution monitoring of rehydrating thalli by automatic weighing combined with chlorophyll fluorescence imaging of maximal PSII efficiency (FV/FM) was applied to determine species-specific rates of vapor uptake and photosynthetic activation. The thin and loosely attached growth form of L. pulmonaria rehydrates and reactivates faster in humid air than the thick L. amplissima, with L. virens in between. This flexible hydration strategy is consistent with L. pulmonaria’s wide geographical distribution stretching from rainforests to continental forests. By contrast, the thick and resupinate L. amplissima reactivates slowly in humid air but stores much water when provided in abundance. This prolongs active periods after rain, which could represent an advantage where abundant rain and stem flow alternates with long-lasting drying. Understanding links between morphological traits and functional responses, and their ecological implications for species at risk, is crucial to conservation planning and for modelling populations under various climate scenarios.  相似文献   

12.
Asplund J  Gauslaa Y 《Oecologia》2008,155(1):93-99
This study aims: (1) to quantify mollusc grazing on juvenile and mature thalli of the foliose epiphytic lichen Lobaria pulmonaria, and (2) to test the hypothesis inferring a herbivore defensive role of lichen depsidones in forests with indigenous populations of lichen-feeding molluscs. Lichens were transplanted in shaded and less shaded positions in each of two calcareous broadleaved deciduous forests, one poor in lichens, one with a rich Lobarion community. Preventing the access of molluscs significantly reduced the loss of juvenile L. pulmonaria, particularly in the naturally lichen-poor forest. Molluscs also severely grazed mature thalli in the lichen-poor forest, especially thalli placed under the more shading canopies. Furthermore, reducing the natural concentration of depsidones by pre-rinsing with acetone increased subsequent grazing significantly, showing that lichen depsidones function as herbivore defence in natural habitats. Our results suggest that mollusc grazing may play important roles in shaping the epiphytic vegetation in calcareous deciduous forests, and that recently established juvenile L. pulmonaria thalli seem to be particularly vulnerable.  相似文献   

13.
Bolli J.C., Wagner H.H., Kalwij J.M., Werth S., Cherubini P., Scheidegger C. and Rigling A. 2008. Growth dynamics after historic disturbance in a montane forest and its implications for an endangered epiphytic lichen. Bot. Helv. 118: 111 – 127. Endangered forest species are often negatively affected by disturbances, which may have long-lasting effects on the distribution, abundance and genetic diversity of such species. To understand the effects of historic disturbances, detailed knowledge of the conditions for survival and recolonisation is needed, and this requires precise information on the perimeter and severity of historic disturbance events. We reconstructed a major historic disturbance (intensive logging followed by windthrow and fire in 1871) in the Swiss Jura mountains to analyse its effect on the disturbance-sensitive epiphytic lichen Lobaria pulmonaria. Tree-ring analysis of old and young Norway spruce trees (Picea abies L.), sampled systematically on a 100 m grid, revealed that (1) the disturbance was of intermediate severity, (2) a large, well-defined area of disturbance was created, and (3) an undisturbed zone remained in the centre of the disturbed area. Acomparison with lichen genetic data from a previous survey revealed that genetic diversity was particularly high in the remnant zone. These results suggest that the lichen survived there, and that it re-colonised the disturbed area both from the edge and from the remnant undisturbed zone. This illustrates that a detailed reconstruction of historic disturbances, as achieved with dendroecology, is very important for understanding the recolonisation process and thus, the conditions for the long-term persistence of disturbance-sensitive species in a dynamic landscape. Submitted 1 November 2007; Accepted 30 August 2008 Subject editor: Sabine Güsewell  相似文献   

14.
We tested the hypothesis that structural variables related to old-growth features affect the distribution of Lobaria pulmonaria in a Mediterranean National Park of Italy. A total of 36 plots, with old-growth characteristics and representing overall three forest types (beech- oak- and mixed- forests) were studied. The lichen was absent in about half of the sites, suggesting that the selection of old-growth forests based solely on structural features is not sufficient to predict the presence of this species, which therefore proves to be rather sensitive and selective. Its abundance was related to high tree circumference and basal area, and to availability of deadwood, confirming the relevant effect of substrate and stand continuity in the conservation of this species and emphasizing its role of indicator species of undisturbed forest ecosystems with long ecological continuity.  相似文献   

15.
Summary Thalli of Lobaria pulmonaria (L.) Hoffm., a nitrogen-fixing epiphyte common in mesic temperate forests, were collected in a Douglas-fir (Pseudotsuga menziesii Franco) forest near Corvallis, Oregon, and maintained for 20 to 40 days in controlled-environment chambers with atmospheric CO2 concentrations of 374 and 700 ll-1. Nitrogenase activity, which was assayed by the acetylene reduction method, was approximately doubled in the lichen maintained in elevated CO2. Increases in nitrogen fixation by lichens may be an important part of the integrated ecosystem response to rising CO2.  相似文献   

16.
This study aims to assess the photoprotective potential of desiccation-induced curling in the light-susceptible old forest lichen Lobaria pulmonaria by using chlorophyll fluorescence imaging. Naturally curled thalli showed less photoinhibition-induced limitations in primary processes of photosynthesis than artificially flattened specimens during exposures to 450 μmol m−2 s−1 in the laboratory after both 12- (medium dose treatment) and 62-h duration (high dose treatment). Thallus areas shaded by curled lobes during light exposure showed unchanged values of measured chlorophyll fluorescence parameters (F V/F M, ΦPS II), whereas non-shaded parts of curled thalli, as well as the mean for the entire flattened thalli, showed photoinhibitory limitation after light treatments. Furthermore, the chlorophyll fluorescence imaging showed that the typical small-scale reticulated ridges on the upper side of L. pulmonaria caused a spatial, small-scale reduction in damage due to minor shading. Severe dry-state photoinhibition readily occurred in flattened and light-treated L. pulmonaria, although the mechanisms for such damage in a desiccated and inactive stage are not well known. Natural curling is one strategy to reduce the chance for serious photoinhibition in desiccated L. pulmonaria thalli during high light exposures.  相似文献   

17.
Forest destruction and disturbance can have long-term consequences for species diversity and ecosystem processes such as seed dispersal. Understanding these consequences is a crucial component of conserving vulnerable ecosystems. In the heavily fragmented and disturbed Kakamega Forest, western Kenya, we studied seed dispersal of Prunus africana (Rosaceae). In the main forest, five forest fragments, and differently disturbed sites, we quantified the overall frugivore community as an indicator for species diversity. Furthermore, we determined the frugivores on 28 fruiting P. africana trees, estimated seed dispersal, crop size and the general fruit availability of surrounding trees. During the overall frugivore census we recorded 49 frugivorous species; 36 of them were observed visiting P. africana trees and feeding on their fruits. Although overall frugivore species richness was 1.1 times lower in fragments than in main forest sites and 1.02 times higher in highly disturbed than in less disturbed sites, P. africana experienced 1.1 times higher numbers of frugivores in fragments than in main forest sites and 1.5 times higher numbers of frugivores in highly disturbed than in less disturbed sites. Correspondingly, seed dispersal was 1.5 times higher in fragments than in main forest sites and 1.5 times higher in more disturbed than less disturbed sites. Fruit availability of surrounding trees and crop size influenced the number of visitors to some degree. Thus, the number of dispersed seeds seemed to be slightly higher in fragmented and highly disturbed sites. This indicates that loss of single species does not necessarily lead to a decrease of ecosystem services. However, loss of diversity could be a problem in the long term, as a multitude of species might act as buffer against future environmental change.  相似文献   

18.
Tree species differ in longevity, canopy structure, and bark texture, chemistry and water storage. Tree species-specific traits play a role in shaping epiphytic vegetation and likely influence the community assembly of organisms feeding on epiphytes. Lichenivorous gastropods, species with calcium-rich shells in particular, need calcium and likely occur more abundantly in and around tree species with high available calcium. We quantified gastropod grazing on the epiphytic lichens Lobaria pulmonaria and Lobaria scrobiculata transplanted to blocks of adjacent trunks of Acer platanoides, Quercus robur and Tilia cordata. We tested the hypothesis that tree species known to have more available Ca, exhibit more grazing damage on transplanted lichens than trees with lower Ca-availability. The grazing pressure was 1.6–1.8 times higher for lichen transplants on Acer and Tilia known to produce litter with easily soluble Ca than on Quercus, which binds Ca as oxalate. Trees with a high grazing pressure on transplants had greater natural abundance of Lobaria virens than of L. pulmonaria. Gastropods preferred L. scrobiculata to L. pulmonaria, evidenced by more observed grazing marks and greater measured biomass loss. We attribute this difference to the lower concentration of carbon-based secondary compounds in L. scrobiculata. However, the strength of the preference varied between the three tree species receiving lichen transplants and was strongest on A. platanoides, while gastropods on T. cordata grazed equal amounts of each transplanted lichen. In conclusion, tree species influenced grazing patterns of gastropods on epiphytic lichens. In addition to bark pH and other factors, we have shown that tree species-specific differences in grazing pressure play a role in shaping the epiphytic macrolichen community.  相似文献   

19.
Habitat degradation through agricultural land use is the major factor threatening lotic ecosystems. Although black flies are major components of these ecosystems, the impact of agricultural land use on species diversity and species assemblages has been largely ignored in tropical streams of the Oriental region. The objectives of this study are to examine patterns of species distribution and species richness and to compare black fly species richness and species assemblages in forest and agricultural streams in Thailand. A total of 143 collections were made from 70 stream sites between June 2007 and May 2008. Whereas 19 black fly species found in these collections were all found in forest sites, only 13 species were found in agricultural sites. High species richness was associated with larger, faster, and cooler streams with larger streambed particles and the presence of riparian trees. Logistic regression analyses revealed that stream size, velocity, and riparian vegetation are among the most important factors determining patterns of spatial distribution. The results are largely consistent with studies in other zoogeographic regions, suggesting the existence of general rules for black fly species distributions. Comparisons of the physicochemical conditions between forest and agricultural streams indicated that streams in agricultural areas are warmer, with higher conductivity and fewer riparian trees. Species richness was significantly higher in forest than in agricultural streams (t = 3.61, P < 0.001). Streams in forest areas were predominantly occupied by S. siamense (73%) but other species were also found at a relatively high frequency (>20%) of the sampling sites. In contrast, streams in agricultural areas were predominantly occupied by S. aureohirtum (>80%) among the sole black fly species at 27% of the sites. The results indicate that agricultural land use has a significantly detrimental impact on black fly diversity and species assemblages. Handling editor: D. Dudgeon  相似文献   

20.
Biological legacies soften pine plantation effects for bryophytes   总被引:1,自引:0,他引:1  
Biological legacies are organic structures and patterns remaining after a disturbance that may contribute to the complexity of the recovering vegetation. Legacies may, in turn, reduce the impacts of human disturbances such as logging and habitat transformation on elements of biodiversity. To examine the effects of biological legacies on biotic responses after disturbance, we surveyed 32 sites for bryophytes in an area subject to large-scale conversion of native eucalypt forest to exotic Pinus radiata D. Don plantations in eastern Australia. We sampled bryophyte and substrate diversity (log, bare ground, upturned tree/log, and trees) in eight sites in each of four landscape context classes: pine plantation stands, elliptical-shaped remnants, strip-shaped remnants, and controls in a large area of contiguous, unmanaged eucalypt forest. We found a muted response by individual species of bryophyte to landscape context. We attribute this, in part, to the presence of logs in the intensively managed pine plantation sites. The boost in bryophyte diversity from species on logs meant that some pine sites supported similar species composition to the continuous eucalypt forest controls. Our findings also underline the importance of local controls and structural variation, including leaving logs and native trees in plantations, for enhancing bryophyte species richness in managed landscapes.  相似文献   

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