Causes
The development, expansion and maintenance of forestry and agricultural activities along with the construction and expansion of urban and/or industrial infrastructure are commonly mentioned as the main causes of land use change. It is evident that those actions generate an immediate change—that is, without intermediate procedures—in the soil, which is why they have been classified as direct causes.
Agricultural activity has used more than a third of the planet's land surface,[3] which translates into around 5,000 mega hectares.[16] Of the land dedicated to agriculture, approximately one third is used for the production of crops for food purposes and the remaining two-thirds are used for the maintenance of meadows and pastures required for grazing.[16] However, mentioning agriculture and livestock as the main direct causes of the Land use change implies encompassing an area that incorporates diverse cultures, companies of all sizes and different methodologies. Therefore, in order not to reflect on the generality, the forms of impact presented by agriculture and livestock activities are described below:
Livestock farming, in the first instance, requires the preparation of the land to operate it as grazing areas and growing forage for livestock. On many occasions, this implies the need to deforest forests or even modify agricultural crops used for the food industry. Its way of manifesting a change in land use includes processes of defoliation, trampling of the land and the return of nutrients through livestock feces and urine.[17].
Agriculture, understood as the “set of techniques and knowledge related to the cultivation or tillage of the land[18]”, has generated changes in land use from the need to increase production. This entails using methods to improve production yield, increase crop intensity (i.e., harvest frequency) and expand the tillage area.[19] Practices that are not sustainable, such as monocultures, imply land degradation, salinization and reduction of agricultural genetic diversity.[20] On the other hand, good agricultural techniques allow for the enhancement of ecosystem benefits such as carbon storage and the conservation of rural landscapes and their biodiversity.
Forest development is understood as the certainty of conservation and use of the diversity of natural resources that it can give us. Forest management produces different impacts, depending on the interest of a given forest area; either the preservation of species within the area or the planting of species that will be exploited to obtain natural resources (such as wood, resin, among other natural products). Due to the different impacts obtained by forest management, during the years 2001 to 2015 it could be said that 3.5 to 6.5 million hectares per year were lost worldwide, which has generated a great loss of ecosystem services such as carbon sequestration.[7].
Given the high productivity rate, that is, due to the harvesting or felling of forest trees, a change in land use can be generated since the trees have the action of protecting the soil from erosion as well as from dehydration. Therefore, when they are cut down, the soil is exposed with a high probability of being eroded.[21].
For its part, the occupation of land use in infrastructure, whether due to urbanization or the installation of industries, has been growing since, first of all in terms of urbanization, the increase in urban areas that has doubled since the 1990s does not project to end. According to the UN, today about 55% of the population lives in urban areas and it is estimated that by the year 2050 this population will increase by 13%.[22] This Added to the population growth that implies greater demand for products, they generate this type of change in land use, which it is worth highlighting mainly affects the surface of forests, wetlands and grasslands.}.
However, in addition to the direct causes described, factors are also considered that, despite not directly changing land use, do influence the management of the negative consequences and the direct causes mentioned; These factors are classified as indirect causes.
According to the IPBES report[3] (2019), the direct drivers that impact terrestrial and aquatic ecosystems—among them, Land Use Change—are associated with other indirect drivers. These, therefore, can be understood as indirect causes of land use change that, although they do not generate an immediate impact, do influence the way in which agricultural activities and the development of infrastructure are carried out. These are incorporated into headings: 1) Demographic and sociocultural, 2) Technological and economic, 3) Institutions and governance and 4) Conflicts and epidemics. Likewise, conceptual ambiguity can play a relevant role when managing measures seeking to reduce the consequences of land use change.
Policies that promote activities related to direct causes without sustainable management influence changes in land use (1). In such a way that legislation and economic incentives can facilitate those activities. As happened in Chile, with Decree Law 701, which encouraged the forestry area through bonuses and tax benefits; However, this process was based on the introduction of exotic species (or introduced species), and in the long term it was one of the main causes of landscape change and the loss of the native forest.[5] Or, the decrease of tropical forest, humid and subhumid forest of the Amazon territory present in Mexico, for use in cattle farming; procedure financed by international organizations[23] (including the World Bank and the Inter-American Development Bank).
It is worth mentioning that, despite not being mentioned within the indirect drivers of IPBES, conceptual ambiguity, that is, confusion or misuse of concepts, can cause serious problems or misinterpretations that lead to uncertainty about the information to be applied, which will be used to solve a problem.
Great importance should be given to this issue of conceptual ambiguity because it has already happened in research, for example in an FAO report that was developed in 2015, in which there was uncertainty about the data that was provided. By not differentiating between the concepts of natural forests and their difference with forest plantations, the estimates that had to be made in relation to the dynamics of their loss were affected and, consequently, the data were not close to reality.[7].