Lineamenti della vegetazione lucana

Abstract

The vegetation of Lucania: an outline. – The vegetation of Lucania is outlined on the basis of the existing literature and of personal observations. After a short review of the botanical literature a new subdivision of this region is proposed taking into consideration both geological and botanical criteria. The various plant formations are described, among them: the vegetation of the sandy beaches along the Ionian Sea; the Policoro Forest on the coastal plain; the Lygeum spartum stands on the clays; the Quercus cents forests, and the Fagus silvatica ones (comprising the two associations Aquifolio-Fagetum and Asyneumati-Fagetum); the relict Abies alba stands; the summit prairies; the Pinus leucodermis stands.     

A stand of birch by Loch Eynort,South Uist,Outer Hebrides

Summary

A stand of birch on South Uist is described. It differs from other stands of wood in the Outer Hebrides by its greater extent, the dominance of birch rather than aspen, and its survival on an exposed site despite grazing pressures.     

Vegetation and soils of the Meikle Kilrannoch ultramafic sites

Summary

The vegetation of two ultramafic sites (MK1 and MK2) at Meikle Kilrannoch are described. MK1 is dome shaped and has much weathering bedrock whilst MK2 is flatter, lacks weathering bedrock and has probably been entirely peat covered. Six vegetation Groups were recognized: I, high-level blanket bog; II and III, grass heath (with II more sedge-rich); IV, dwarf shrub heath; V and VI, debris (an open vegetation on stony skeletal soils). Vegetation maps were produced which had five mapping units: Group I, Groups II and IH combined, Group IV, Groups V and VI combined, and non-vegetated eroding peat. Three main soil types occur: peat, which underlies Group I; a complex of freely draining magnesian brown soils and imperfectly drained magnesian gleys which bear Groups II–IV; and skeletal soils, derived either from weathering bedrock (MK1 only) or ultramafic drift, which bear vegetation in Groups V or VI. The rare plants are commonest in, but not restricted to, debris vegetation on skeletal soils. The likely plant toxicity of soil magnesium at the sites is reaffirmed but it is suggested that the low plant cover in the debris is more likely to result from low nutrients or intensive frost action or both. Floristic differences between MK1 and MK2 are discussed and quantified for Lychnis alpina (which had 68000individuals on the former site and 46 on the latter) but the causes of the differences remain unexplained.     

Nest-site selection by crossbills Loxia spp. in ancient native pinewoods at Abernethy Forest,Strathspey, Highland

Capsule Birds preferred stands with a particular density of trees, perhaps to avoid predation, and they selected aspects sheltered from prevailing winds.

Aim To describe the nesting habitat and tree selection by crossbills in a restricted pinewood habitat in Scotland.

Methods Scots Pines used by nesting crossbills were described and compared with randomly selected pines. Nest aspect was related to wind strength and direction.

Results The crossbills selected trees at a density of 50–60 trees/ha. Such stands may be sufficiently dense to provide cover, yet occur at a low enough density to minimize being visited by potential arboreal predators, such as Red Squirrels and Pine Martens. Crossbills tended to nest on lateral branches on the northeast side of crowns. Tree crown development was not asymmetric, so the birds may choose the northeast side to shelter from the prevailing southerly to westerly winds.

Conclusion Stands of pines at a low density need to be maintained for the benefit of crossbills.     

Rumex aquaticus L. at Loch Lomondside

Summary

A new alliance of spring vegetation dominated by the leafy liverwort Anthelia julacea is described from the montane regions of Britain. It is distinguished floristically and ecologically from similar alpine late snow bed communities in Scotland and Scandinavia. The classificatory position of the stands of this vegetation type is discussed with reference to continental and British systems and it is concluded that the erection of a new alliance is justified on floristic grounds.     

Ptychomitrium subcrispatum Thér. & P.de la Varde,an east southern African species excluded from the Cape Verde bryoflora

Abstract

Pictolejeunea levis, a new species of Lejeuneaceae found in N.E. Cuba, is described and illustrated. The species stands out within Pictolejeunea on account of its smooth leaf cells and the presence of ocelli on dorsal and ventral epidermal cells of the stem. Differences between this and the other four known species in the genus are discussed.     

Correcting Misperceptions about the History of <Emphasis Type="Italic">Castanea</Emphasis> Stands in <Emphasis Type="Italic">Satoyama</Emphasis> in Japan

Correcting Misperceptions about the History of Castanea Stands in Satoyama in Japan. Mistaken ideas about the naturalness of past and present landscapes are widespread in diverse cultures and in the scientific literature, and many of these ideas are only now being seriously challenged by current research (e.g., Erickson 2006; Fairhead and Leach 1996; Hall 1998; Ramankutty and Foley 1999; Willis et al. 2004). For example, the chestnut, Castanea crenata, has long been an important tree in Japanese culture, which has been cultivated, among other things, for its much loved edible nut and its valuable timber. Today, the widely-held view in Japan, which also appears in the scholarly and popular literature, is that in the past Castanea stands covered a large area throughout Japan, and these stands only disappeared because of economic development, especially in association with railway construction. Otaru, Hokkaido, is one of the places where people believe Castanea stands covered a large area and were deforested only recently. Local people in Otaru believe that the stand in Temiya Park has existed since the Jomon Period. For a more accurate historical perspective on Japanese forestation, we have performed pollen analysis to clarify the timing of the introduction of the Castanea tree into Otaru region and to reveal the history of this specific Castanea stand in Temiya Park. The results indicate that Castanea was first found in Otaru region 7100 B.P., but that it was not cultivated extensively until recently. Based on our study, and on data from this area dating to the late 19th century, we concluded instead that the Castanea stand we studied in Temiya Park, Otaru, was established after the mid-20th century. We believe the results of this study are applicable to Castanea stands in other parts of Japan as well.     

Methane Exchange in a Coastal Fen in the First Year after Flooding - A Systems Shift

BackgroundPeatland restoration can have several objectives, for example re-establishing the natural habitat, supporting unique biodiversity attributes or re-initiating key biogeochemical processes, which can ultimately lead to a reduction in greenhouse gas (GHG) emissions. Every restoration measure, however, is itself a disturbance to the ecosystem.MethodsHere, we examine an ecosystem shift in a coastal fen at the southern Baltic Sea which was rewetted by flooding. The analyses are based on one year of bi-weekly closed chamber measurements of methane fluxes gathered at spots located in different vegetation stands. During measurement campaigns, we recorded data on water levels, peat temperatures, and chemical properties of peat water. In addition we analyzed the first 20 cm of peat before and after flooding for dry bulk density (DBD), content of organic matter and total amounts of carbon (C), nitrogen (N), sulfur (S), and other nutrients.ResultsRewetting turned the site from a summer dry fen into a shallow lake with water levels up to 0.60 m. We observed a substantial die-back of vegetation, especially in stands of sedges (Carex acutiformis Ehrh). Concentrations of total organic carbon and nitrogen in the peat water, as well as dry bulk density and concentrations of C, N and S in the peat increased. In the first year after rewetting, the average annual exchange of methane amounted to 0.26 ± 0.06 kg m^-2. This is equivalent to a 190-times increase in methane compared to pre-flooding conditions. Highest methane fluxes occurred in sedge stands which suffered from the heaviest die-back. None of the recorded environmental variables showed consistent relationships with the amounts of methane exchanged.ConclusionsOur results suggest that rewetting projects should be monitored not only with regard to vegetation development but also with respect to biogeochemical conditions. Further, high methane emissions that likely occur directly after rewetting by flooding should be considered when forecasting the overall effect of rewetting on GHG exchange.     

Preferences of dead wood inhabiting bryophytes for decay stage,log size and habitat types in Hungarian beech forests

Abstract

This study describes the quantitative preferences of epixylic bryophytes for decay stages, log size and habitat type. The two habitats investigated were zonal (situated on plateaux without extreme microclimatic conditions) and ravine-like near-natural beech stands. Preferences of 30 bryophyte species are described using logistic regression modelling. The species pool differed between habitat types. In the ravine-like forests more species are found. Regionally rare epixylic species (mainly liverworts) were limited to these forests. The species richness of individual logs was also higher in the ravine-like than in the zonal forests and the proportion of logs of all sizes colonized by bryophytes was higher in the former. The species were classified into four categories on the basis of their preference for decay stages: strict epixylics, indifferent species, preferential epixylics and epiphytes. The epixylics and preferential epixylics prefer advanced decay stages while the latter extend further into earlier decay stages than strict epixylics. Common epixylic species have a wider tolerance to decay stage than rare ones. Probabilities of species occurrence increase with log size, more strongly in zonal stands than in ravines. A simple successional scheme for bryophyte succession on dead wood is proposed on the basis of the observed species responses.     

Il Contributo di Maria Selebam de Cattani Agli Studi Delle Alghe Marine e di Certe Sue Raccolte Conservate a Venezia

Abstract

Phytosociology, ecology and chorology of snowbed vegetation in Croatia were researched. Snowbed stands, found only in freezing ravines and dolines of the Liburnian karst and Velebit Mountains (NW Dinaric Alps, NW Croatia), were classified into the association Drepanoclado-Heliospermetum (Salicion retusae, Arabidetalia caeruleae, Thlaspietea rotundifolii). Those stands, exposed mostly to the north and shaded for the majority of the growing season, were developed on more or less settled periglaciar screes and boulders in the coldest parts (bottoms, smaller ditches) of the dolines with long-lasting snow cover. Due to lower altitude of Croatian mountains, snowbed vegetation could be found only azonally, in freezing ravines surrounded by altimontane and subalpine (fir-)beech and spruce forests, where these stands manage to thrive due to specific microclimatic conditions. Snowbeds host some rare, endangered and/or protected plant species in Croatia. Vulnerability of the flora and vegetation of snowbeds in Croatia is briefly discussed.     

Regeneration and coexistence of two Abies species dominating subalpine forests in central Japan

Summary The mechanism of coexistence of the dominant firs Abies veitchii and A. mariesii is described in relation to regeneration patterns for climax subalpine forests of the northern Yatsugatake Mountains, central Honshu, Japan. Two mature stand types, pure conifer stands of Abies spp., and mixed stands of Abies spp. and hardwoods (mainly the birch Betula ermanii), are distinguished. Pure stands are likely to show simultaneous decay, followed by evenaged regeneration of stand-floor seedlings (<20 cm tall), Rapidly growing A. veitchii dominates over A. mariesii in this type of regeneration, which is occasionally invaded by light-demanding Betula. In constrast, mixed stands degenerate rather slowly, followed by the regeneration of Abies from the bank of suppressed saplings (>20 cm tall), which persist only in mixed stands. The more shade-tolerant A. mariesii is supeior in this type of regeneration, while Betula does not succeed, and mixed stands change to pure stands with time. The fact that two patterns of Abies regeneration occur in a certain ratio in the forest is what enables the two Abies species to coexist. A simple dynamical system model supports this conclusion.     

The impact of forest disturbance on the genetic diversity and population structure of a late-successional moss

Abstract

Human-induced disturbances threaten the genetic variation of wild plant populations. The genetic diversity and spatial population structure of the moss Isothecium myosuroides, a late-successional forest species, was investigated in subtropical cloud forests (La Gomera, Canary Islands) using inter-simple sequence repeat (ISSR) markers. Inter- and intrapopulation genetic variability was assessed in two ancient and four disturbed forest stands, which were classified according to their vegetation, forest age and type of disturbance. ISSR analysis of 144 epiphyte colonies with eight primers resulted in 211 reliably amplified bands. Our findings show that in disturbed forest stands, the population structure is increased, and the genetic diversity decreased compared with the levels observed in ancient forests. Although ancient and disturbed stands were located relatively close to each other, the (re-) established epiphyte populations did not reach their original genetic condition, 40 years following disturbance. Strong differentiation among populations of I. myosuroides at several spatial scales and differences in genetic diversity are mainly related to the local environmental conditions and the availability of suitable microhabitats in anthropogenically disturbed forest stands.     

Tree-stand age preferences of breeding Lesser Whitethroats Sylvia curruca in a forest in Central Poland

Capsule Lesser Whitethroats Sylvia curruca nested within a large forest complex in central Poland. They showed a strong preference for stands of pine Pinus spp. aged 9–15 years, in which they nested at a high density (31 pairs/km²). The presence of these stands of young conifers was the result of particular forest management practices and certain low-fertility soil types. It is concluded that Lesser Whitethroats do not avoid the interior of forests per se, but simply do not usually find suitably large patches of preferred habitats within them.     

Use of an antiarrhythmic drug against acute selenium toxicity

ObjectiveSelenium is an essential trace element. But, selenium may have toxic effects in high doses. There are no proven antidotes or curative treatments for acut selenium toxicity. Treatment involves stopping the exposure and providing supportive care for symptoms. Therefore, it is necessary to find more effective substances in the treatment of selenium toxicity. The aim of this study was to increase the survival rate of animals by supporting the heart with amiodarone and to determine the effect of amiodarone on the pathological, hematological and biochemical parameters in acute selenium intoxication.Methods64 Wistar-Albino rats were divided into four groups. Group I was given only distilled water, Group II was given 18 mg/kg dose of amiodarone, Group III was given 18 mg/kg amiodarone and 10 mg/kg sodium selenite and Group IV was given sodium selenite 10 mg/kg (LD₅₀ dose)orally.Results11 of the 16 animals in Group IV died within the first 48 h of drug administration. However, no deaths were observed in the rats in Group III. No hematological changes were observed. Biochemically, CK, CK-MB and LDH levels of Group IV were higher than the other groups on both the 2nd and 10th days. In Groups II and III, this serum level decreased, and vitamin B12 levels increased. In macroscopic inspections of the organs of Groups III and IV, slight paleness was detected. Histopathologically, degenerative changes in tissue were observed, especially in Group IV.ConclusionThis study shows that amiodarone application has a reducing effect on selenium toxicity. This was because amiodarone protected the heart by reducing CK and CK-MB levels and increased vitamin B12 levels, which play a role in the synthesis of S-adenosyl methionine that converts selenium into a nontoxic form.     

Stand- and plot-level changes in a boreal forest understory community following wildfire

Background: Boreal forest understory plant communities are known to be resilient to fire – the species composition of stands after a fire is quite similar to the pre-fire composition. However, we know little about recovery of individual plants within particular locations in forest stands (i.e. plot-level changes) since we usually do not have pre-fire data for plots.

Aims: We wanted to determine whether species recruited into the same or different locations in a Pinus banksiana stand that experienced a severe wildfire.

Methods: We used pre-existing permanent plots to evaluate the cover of understory after an unplanned wildfire.

Results: Across the entire stand nine of 47 species showed a significant change in cover. The largest change in a plant functional group was in the mosses, with all species present before fire being eliminated. There was no change in species diversity or total cover. At the plot level, species composition showed a much greater change. An average of 47% of the species present in a plot before the fire were absent in the same plot after the fire, and the total species turnover in plots was 88% of the species present before the fire. The plots showed a similar shift in species composition.

Conclusions: These results confirm that boreal forest communities show a high degree of resilience to fire, but within a forest stand species will be found in different locations following fire, potentially exposing them to a different set of biotic and abiotic conditions in these new locations.     

Co-ordination between leaf biomechanical resistance and hydraulic safety across 30 sub-tropical woody species

Background and AimsLeaf biomechanical resistance protects leaves from biotic and abiotic damage. Previous studies have revealed that enhancing leaf biomechanical resistance is costly for plant species and leads to an increase in leaf drought tolerance. We thus predicted that there is a functional correlation between leaf hydraulic safety and biomechanical characteristics.MethodsWe measured leaf morphological and anatomical traits, pressure–volume parameters, maximum leaf hydraulic conductance (K_leaf-max), leaf water potential at 50 % loss of hydraulic conductance (P50_leaf), leaf hydraulic safety margin (SM_leaf), and leaf force to tear (F_t) and punch (F_p) of 30 co-occurring woody species in a sub-tropical evergreen broadleaved forest. Linear regression analysis was performed to examine the relationships between biomechanical resistance and other leaf hydraulic traits.Key ResultsWe found that higher F_t and F_p values were significantly associated with a lower (more negative) P50_leaf and a larger SM_leaf, thereby confirming the correlation between leaf biomechanical resistance and hydraulic safety. However, leaf biomechanical resistance showed no correlation with K_leaf-max, although it was significantly and negatively correlated with leaf outside-xylem hydraulic conductance. In addition, we also found that there was a significant correlation between biomechanical resistance and the modulus of elasticity by excluding an outlier.ConclusionsThe findings of this study reveal leaf biomechanical–hydraulic safety correlation in sub-tropical woody species.     

Amelanchier alnifolia vegetation in eastern Idaho,USA and its environmental relationships

Fifteen shrub stands of Amelanchier alnifolia vegetation were studied using Braun-Blanquet procedures, tabulated, and ordered by Twinspan, Decorana, and field experience into 5 groups of stands. The stands occurred on the lower slopes of the southwestern Teton and southeastern Big Hole mountains of eastern Idaho and in-and outside a U.S. Forest Service exclosure above the Hoback River in adjacent Wyoming. The ecology of this Amelanchier vegetation as a whole and of the 5 groups of stands is discussed using Jenny's factors of soil formation (1941, 1958, 1980) as a framework. Plant indicator values (Ellenberg 1979, 1988) which rank species on their occurrences in relation to light, temperature, continentality of climate, water availability, soil reaction (pH), and soil nitrogen supply, were independently assigned to the 121 species of vascular plants encountered in the described stands.     

A synecological investigation of Matteuccia struthiopteris — dominanted stands in Western Norway

This investigation is based on phytosociological and ecological analyses of stands dominated by M. struthiopteris within its main distributional area in Western Norway. The distribution and floristical composition of such stands are related to different environmental parameters such as regional climate, soil and topography. The data are analysed by numerical methods, of which two-way indicator species analysis (TWINSPAN), canonical correspondence analysis (CCA), and simple discriminant functions (DISCRIM) are the most useful. Few stands occur in areas where the mean July temperature is below 12.0 °C, and where the mean January temperature is higher than 0 °C. The soil is rich in metal cations, with a base saturation mostly higher than 50% in the B-layer. Based on a TWINSPAN classification of the 230 investigated stands, 9 different groups (types) are distinguished. Many stands have a tree layer of Alnus incana, while stands with a canopy of Betula pubescens, Fraxinus excelsior and Ulmus glabra are considered to be marginal sites for M. struthiopteris. The types described are interpreted as belonging to the Pruno padi-Alnetum incanae, Alno incanae-Fraxinetum excelsioris and Alno incanae-Ulmetum glabrae associations within the Alno-Ulmion alliance. The floristic composition of the quadrats is highly correlated with the altitude/temperature gradient. The other important factor is interpreted to be soil moisture. Soil richness is poorly correlated with the floristic composition of the different stands. Several stands represent a regeneration stage after cessation in cultivation, while others appear to have been very little influenced by human activity.