**4. Human effects and conservation efforts**

Nowadays, one-third of the human population is already feeling the negative effects of degradation, which include soil erosion, salinization, draining of marshes and bogs, and deforestation [71]. There are already more than 500 million hectares of degraded forests in the tropics and this area is steadily increasing [72]. Deforestation is caused by economic, demographic, technological, and political factors [73]. In total, 52% of the felled timber becomes lumber, 31% firewood and charcoal, 9% is the victim of an uncontrolled fire, and 7% is lost due to grazing [74]. Every biome is losing NPP due to human activities, with a degraded area reaching 2.7 billion hectares worldwide [75]. In abandoned areas, vegetation is able to regenerate. This is often done deliberately as part of a rotation system in order to regenerate soil nutrients [76] or in response to socioeconomic impacts, which alter profitability, access to labor, capital, and markets [77]. Secondary forests appear in the place of previously deforested forests, and their area increased in Brazil from 10 to 17 million hectares between 2004 and 2014, which is very important from the viewpoint of the situation of rainforests in the twenty-first century [78, 79]. Today, there are several programs to restore the original natural vegetation. Theoretical knowledge of the succession process in a given location and consideration of climatic conditions allow decision-making in order to achieve the goal of restoring a given area to a near-natural state or a condition desired by the human community [80]. During the restoration program, vegetation should be monitored continuously. The data obtained as a result of monitoring provide feedback, which can be used to adjust predictions and modify plans if necessary. In addition, monitoring can be the basis for other scientific work, increasing our knowledge of succession and vegetation dynamics. In order to control succession, it is important to know, for example, when it is time for the emergence of desirable species or for their artificial dispersal. What will their mortality be due to the competition? How to reduce harmful abiotic effects? The spread of emerging undesirable adventitious species also needs to be controlled or they have to be eradicated [81]. An adequate response to ongoing degradation is often lacking due to missing adequate knowledge of the causes that trigger it. Even measures that have been initiated are not always successful if the process of degradation itself and the underlying causes are not linked. In the absence of appropriate countermeasures, vegetation cover and soil nutrients may disappear [82].
