Search results for "ecological succession"

Seventy-year changes in tree species composition and tree ages in state-owned forests in Latvia

2011

Abstract During the last 100 years, forest management in Latvia has gradually become more and more focused on industrial logging, which can be expected to have affected the tree species composition and age distribution across the landscape. These changes need to be considered in forest management and conservation of biological diversity. The aim of the study was to use forest records to reconstruct the tree species composition and age distribution in the North Vidzeme Biosphere Reserve in northern Latvia for the period, 1929–1941. These data were compared to a data-set from 2008, to determine the changes that transpired during a period of intensification of forest management. The silvicultu…

Long-Term Observations of Soil Mesofauna

2010

General problems connected with planning, sampling, and data processing of long-term research of soil mesofauna are discussed, based on two case studies: (i) the Bremen study of predatory mites (Gamasina) covering 20 years of secondary succession on a ruderal site in northern Germany and (ii) the Mazsalaca study of the effects of climate warming on Collembola of coniferous stands in the North Vidzeme Biosphere Reserve, Latvia, covering 11 years. The findings from both sites are embedded in an array of environmental data. The results from Bremen document the asynchrony of different biota in successional dynamics. The long-lasting increase of the species numbers of soil predatory mites (Gamas…

New knowledge on the Monte Conca gypsum karst system (Central-western Sicily, Italy)

2011

The Monte Conca karst system is located in Central-Western Sicily, where Messinian evaporites are widespread. Here, the evaporites lie on lower Messinian-middle Serravallian clayey-marly-sandy deposits and are overlain locally by Pliocene marly limestones. These successions are affected by E-W, and to a lesser degree N-S and NW-SE, high-angle faults that have also produced lateral contacts between the gypsum units and the clayey-marly deposits. The cave passages reachaltogether about 2.4 km in lengthand 130 m in depth, and the system consists of a sink cave, a resurgence and a relict resurgence. At large scale it is characterized by superimposed levels of sub-horizontal galleries connected …

Life-form adaptations and substrate availability explain a 100-year post-grazing succession of bryophyte species in the Moricsala Strict Nature Reser…

2013

Bryophyte species composition, richness and life-form distributions were studied in a succession after termination of land-use as meadows and pasture in the Moricsala Strict Nature Reserve. Detailed lists of bryophyte species in various vegetation types, which were produced in the early 1900s by Karl Reinhold Kupffer, were compared with those prepared from 2006 to 2010 to determine changes in species composition. Colonisations and extinctions of bryophyte species and life forms could be explained by increases in available substrates (living trees, dead wood, ground layer disturbance patches), and increasingly shaded conditions. In each forest type, the species diversity (alpha diversity) in…

Is the Distinction between State Continuity and State Succession Reality or Fiction?

2001

The Landslide of Agrigento Hill (Sicily, Italy)

2018

This paper illustrated the geological, morphological and hydrogeological studies performed for the analysis and monitoring of the landslide involving the northern side of the hill of Agrigento (335 m a.s.l.) on which the ancient Cathedral was built during the 11th Century. The hill is made of a typical Plio-Pleistocene transgressive succession made of clays (M. Narbone formation), calcarenites, sands and clayey soils (Agrigento formation). The area has been unstable since 1315, involving both the little-welded, very porous and fractured calcarenitic sections (E-W) from Pleistocene and the clay layers interstratified within these sections. Since 1924, from time to time, various typologies of…

Microbial Succession in the Gut: Directional Trends of Taxonomic and Functional Change in a Birth Cohort of Spanish Infants

2014

In spite of its major impact on life-long health, the process of microbial succession in the gut of infants remains poorly understood. Here, we analyze the patterns of taxonomic and functional change in the gut microbiota during the first year of life for a birth cohort of 13 infants. We detect that individual instances of gut colonization vary in the temporal dynamics of microbiota richness, diversity, and composition at both functional and taxonomic levels. Nevertheless, trends discernible in a majority of infants indicate that gut colonization occurs in two distinct phases of succession, separated by the introduction of solid foods to the diet. This change in resource availability causes…

Trying to link vegetation units with biomass data: the case study of Italian shrublands

2014

Although their carbon stock is relevant in assessing the baseline for the negotiation of future agreements with respect to carbon balance, there still are few available studies concerning the biomass and the net ecosystem exchange capacity of Mediterranean shrublands. In this chapter a preliminary overview on the biomass values concerning Italian shrubland communities and/or their dominant/ characteristic woody species is provided. Many useful data on above- and belowground biomass issued from investigations carried out in other Mediterranean countries and concerning plant communities, which share the same ecological, floristic and structural traits of Italian shrublands. A preliminary find…

The impact of Pinus halepensis mill. afforestation on mediterranean spontaneous vegetation: do soil treatment and canopy cover matter?

2012

We investigated central Mediterranean Pinus halepensis plantations under semi-arid climate in order to evaluate the combined effect of soil treatment and afforestation practices on spontaneous plant species composition, richness and evenness, and on the trend and speed of vegetation dynamics. Phytosociological releves of three different plot typologies, i.e. (1) soil-treatment and plantation, (2) only soil-treatment, (3) no soil-treatment and no plantation, were compared by (a) multivariate analysis and (b) with reference to species richness and evenness. Moreover, in order to compare vegetation dynamics within the plantations with those ones ongoing in semi-natural garrigue communities, we…

Olive agroforestry systems in Sicily: Cultivated typologies and secondary succession processes after abandonment

2011

The first part of this study provides an overview on Sicilian olive systems. Subsequently, the study describes the different typologies of cultivated agroforestry systems present in South-Eastern Sicily employing olive trees in association with other Mediterranean tree species, in particular for the production of firewood, coal and animal food (downy or pubescent oak, holm oak, cork oak), but also in association with forage or grazing species (oat, barley, vetch, etc.) or cereals. The study shows that Sicilian agroforestry systems are much more diversified than it was known so far. In the second part, the study describes the spontaneous colonization processes by plants, observed in abandone…