Forests & shrubland
LEDD issues in forests & shrubland: Italy and Matera
Editors note: text source D311 section 3.1.2
Forest productivity decline
Forest productivity decline in the Mediterranean region and thus in large areas of southern Italy represents an LEDD issue which is closely related to direct drivers of change, such as climate change, agriculture and tourism. The severity of the climate linked with forest mismanagement or the use of poor silvicultural practices and overgrazing are responsible for forest and ecosystem productivity decline at regional and local scales. In particular, these drivers affect nutrient cycling properties and physical properties such as soil characteristics. The Matera Study Site represents an area sensitive to forest productivity decline, due to its geomorphology, climate, and human activities. From a climate perspective, the Matera study site is particularly affected by frequent heat and drought waves during the summer season which dramatically reduce water availability, and thus the photosynthetic processes. This loss in productivity combined with forest fires and/or other practices like overgrazing in forest and shrubland is responsible for most of the loss of ecosystem productivity. At a local scale, forest mismanagement or poor silvicultural practices generally result in stand ageing.
Loss of biodiversity
In the Matera Study Site, loss of biodiversity represents a major LEDD issue affecting forests and shrublands, as is the case in the rest of the Mediterranean region of southern Italy. Recurrent anthropogenic and natural perturbations are responsible for this loss in biodiversity. As in the rest of the Mediterranean basin, the forests resources of the Basilicata region have long been exploited, leading to deforestation and forest fragmentation in past centuries. In many areas, important re-forestation projects carried out during the last century have produced even-aged pure conifer stands. Another case is the transformation of natural forests into coppices, with a simplification of forest structure and species composition. In forest stands characterized by good soil fertility, forest management has been oriented towards maximizing wood production, with even-aged structures and the prevalence of one or few tree species. Figure 1 shows the distribution of forest types with different biodiversity levels for the Matera study site.
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Figure 1. Distribution of forest types with different biodiversity levels for Matera study site. Source: (Spatial analysis of the Basilicata Region Forest Map and Regional Biodiversity Map produced by the authors). |
Forest fragmentation
As in the rest of Mediterranean region, forest fragmentation represents an important threat to forests and shrublands in the Matera study site. Human activities such as agricultural land conversion, overgrazing, forest fires, urbanisation and tourism represent the main drivers of forest fragmentation at the study site level.
Soil erosion and degradation
Soil erosion processes are widely distributed within the forest environment of the Matera study site. The geomorphology of the area provides favourable conditions for land degradation processes.
In the study area, repeated fire events have led to devolution of forest succession stages. Thus, the Holm oak high forest degrades to a sparse forest and then to a shrubland mixed with Phillyrea, Cystus, amongst other species. Further impact from fire or excessive grazing will lead to a further reduction of trees and shrubs and the area will eventually become grassland, dominated by geophytes such as the Asphodelus. The spreading of fire, which reduces the amount of biomass, has negative effects on the soil with an increase in erosion, deterioration of chemical and physical characteristics and increased risk of landslides. In particular, alterations of soil chemical and physical characteristics involve changes in porosity with a general reduction in soil ventilation and infiltration capacity, reduction in organic matter content and development of a waterproof layer to a depth of 10-15 cm.
In the Calanchi (“badlands”) area, the particular conditions of microtopography (slope, aspect and length) represent key factors increasing the soil erosion rate (Figure 2).
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Figure 2. Afforestation in Calanchi areas. Source: (Spatial analysis of the Basilicata Region Forest Map and Calanchi “Badlands” Map by the authors). |
Water stress and phytosanitary deterioration of forest cover
The Mediterranean coastal and upland study site of the Matera prefecture is an area prone to water stress events, due to its climatic characteristics, with repeated drought events occurring during the year.
In this context, the main forest areas affected by water stress and phytosanitary deterioration are the coastal pinewood forests and coniferous forests in the Calanchi area. In these areas, poor seasonal climatic conditions and soil degradation create a high sensitivity to water stress and induce poor quality vegetation, increasing vulnerability to parasitic attack (most often processionary moth and scolytus).
Desertification
The study site of the Matera prefecture can be considered very representative of the Mediterranean region’s main characteristics. It is particularly prone to land degradation and loss of organic matter and, thus, to desertification. The increasing frequency of extreme climatic events, ecosystem overexploitation and, in some cases, land abandonment represents the main causes of the desertification process.
In particular, desertification can be considered as the result of two main opposing processes: 1) land overexploitation; and 2) land abandonment. The first process is generally driven by poorly managed agriculture and grazing that result in land and ecosystem degradation such as soil erosion and deterioration, loss of organic matter, loss of water holding capacity, ecosystem fragmentation and loss of ecosystem productivity. The second process is generally driven by socio-economic factors such as small farm size and property fragmentation, low income from agricultural activities and socio-cultural change driving rural migration towards urbanised areas. In this context, global climate change accelerates the biophysical processes which underlie the main LEDD issues.
Socio-economic issues
The Mediterranean coastal and upland study site of the Matera prefecture presents most of the socio-economic issues related to forest ecosystem and shrubland degradation processes. In the last few decades, the study area has been characterized by continuous depopulation, generally related to the loss of profitability of agricultural and forestry activities (Regione Basilicata 2008b). LEDD issues affecting the Mediterranean region in general also affect the Matera Prefecture study site, with loss in ecosystem productivity which results in loss of income. This situation also worsens due to a generalised lack of technological assistance, the types of farms present and the land property fragmentation. A main consequence of depopulation and migration of younger people to urban areas is population ageing, land abandonment and loss of cultural heritage (Fuccella et al. 2010).