Human impact on the landscape
Human modification of the Earth’s landscape is as old as humankind itself; it might be said that human history is also the history of anthropogeomorphology. Potential human impact on the environment is basically determined by two factors: technical progress and population growth.
Until the early Holocene (12,000 years BP) man used wood, bones and chipped flint implements and basically followed a hunting-gathering course in life. However, he also began to grow cereals, peas and lentils as well as to domesticate some wild animals.
As a result of very fast demographic, socio-economic and technological changes, the level of modification of the landscape is increased.
Consideration of the most important relief characteristics as a natural factor which directly determines the intensity of natural processes and different types of utilization nowadays is quote modified by scientific and technological development. Modification of the natural environment by human impact led to a change of the existing landscape, and therefore we are experiencing expansion of technological type of landscape, acceleration of soil erosion, river management, ore exploitation, etc.
This type of human effects has resulted in numerous natural responses. However, we may expect the influence of geomorphologic changes as well. Therefore each human activity should be adjusted with good understanding of natural processes, its dynamics and structure, especially geomorphologic ones. Only in that way we can be aware of consequences that may come due to changes of the existing relief conditions.
Land use changes are among the most important transformations of the Earth’s land surface and they may be the most significant cause of global environmental change. Currently in many parts of the world, human activities are the main forces shaping land use changes. In particular the areas of the Mediterranean basin are being profoundly transformed by human activity. As a result only 4.7% of its primary vegetation remained unaltered. In fact, agricultural lands, evergreen woodlands and maquis habitats, that dominate the present landscape of the Mediterranean basin, are the result of anthropogenic disturbances over millennia.
In this regard, it is worth mentioning a particular tecnique called “slash-and-burn”, used to fertilize the soil. Wide areas of forests, underbush and meadows dedicated to pasture were set on fire, so that the mineralized organic matter could enrich the soil with elements ready to use for farming and growing. Nevertheless, the fire extent was diffult to control, and it usually exceeded the pasture area, destroying wider woodlands.
The spread of this technique caused the loss of large part of the Mediterranean scrub and the original forests that used to cover mountains and hills in Central and Southern Italy.
Nowadays, as well as in the past, the main reasons for brush fires in Italy is the human intent to eliminate stubble and other residues of cultivation, to “clean” wild areas and to stimulate the growth of edible plants, especially wild asparagus and valuable mushrooms. The fire set by the shepherds (to increase the fodder availability or to express rivalry among each other) is the cheapest way to make room for the herds, to eliminate weed and infesting plants and to re-create paths previously interrupted by the dynamism the agro-ecosystems abandoned by humans.
It may easily happen that fires set intentionally for pastoral or hunting purposes turn into uncontrolled blazes, especially when the climate is dry and hot. For instance, in spring 2017, a very bad year for Italian forests, 25.071 hectares got burnt in Sicily (Source: Legambiente data elaboration from European Commission Emergency Management Service Copernicus EMS updating at 26/07/2017).