Soil loss due to erosion is tolerable when the rate of soil renewal is not exceeded. Most of the degradation and loss of soil is due to deforestation, overgrazing, and agricultural activities. However, depending on the erosive agent, soil degradation occurs mainly by water erosion ^[1][2][1,2], followed by wind, chemical, and physical factors [3]. The vegetation protects the soil from damage against erosion and reduces the disaggregation and transport capacity of the edaphic material, intervening at the beginning of a rain event and intercepting part of the water that falls on the leaves and branches of the plant [4]. It has been claimed that any land use that modifies the type and density of the original plant populations and exposes the soil leads to its degradation [5]. This risk situation has developed the need to protect natural areas in many countries as a strategy, to save habitats or landscapes from the destruction that receive the social and legal consideration of natural heritage ^[6][7][6,7].

Despite the great complexity in the identification of risk areas and ecological protection within PNAs and BZ, the use or remote sensing and Geographic Information Systems (GIS) [8] has facilitated and improved the analysis and characterization of the physical environment, types, and classes of plant cover, soil, etc. Using sophisticated means of spatial analysis, improving the evaluation and efficiency of large volumes of available information, associated above all with land use planning studies ^[9][10][9,10]. Thus, the combination of remote sensing, GIS, and the Global Positioning System (GPS), allow incorporating and associating field information, digital cartography, and remote sensors, which facilitates the spatial and integrated treatment of existing information [11].

Protected natural spaces (PNS) in Europe or Protected Natural Areas (PNA) in Latin America, are environmental policy instruments that support environmental conservation strategies [12]. PNAs are the cornerstone of the strategy for the conservation of biological diversity, by maintaining the integrity of the ecosystems of a region, therefore they play a central role in the greater objective of achieving a sustainable society [13]. These PNAs and their BZs (buffer zones) are not isolated units, but rather linked to their geographic environment by ecological, economic, political, and cultural factors, with the possibility of reconciling the integrity of the ecosystems ^[14][15][14,15]. Within them, the Protection Forests are natural areas established to protect the upper or collecting basins, the riverbanks, and other watercourses, against the erosion ^[13][16][17][13,16,17].

In Peru, the PNAs together form the National System of Natural Protected Areas by the State (SINANPE), under the jurisdiction of the Ministry of Agriculture through the National Service of Natural Protected Areas (SERNANP) by the State. The PNAs with definitive status (SINANPE) are classified into nine categories: National Reserves, National Parks, Protection Forests, Game Preserves, Community Reserves, Landscape Reserves, Wildlife Refuges, National Sanctuaries, and Historic Sanctuaries ^[18][19][20][18,19,20]. In addition, the Reserved Zone is considered ANP with transitory status ^[21][22][21,22].

2. Main Risk Zones Identified and Categorized in Pagaibamba Protection Forest

In the PNA and the BZ, Soil 1 and Soil 3 are characteristic, respectively, which generate a high susceptibility to erosion in both areas, with the formation of frequent gullies in clay and loamy materials ^[23][49]. The problem increases in the PNA, as these soils are spread over steep slopes with slopes of 50–75% ^[24][50]. They are areas with very rugged topography, subject to a very high potential for water erosion, and of high agrological quality. They are covered by scrub and humid mountain forest, still in its natural state of conservation, due to which they fulfill the role of protecting the soil from the direct impact of raindrops, reducing the disaggregation and transport capacity of runoff ^[25][51]. They also exert a process of holding the soil by the roots of the plants ^[26][52] and constitute an adequate refuge for wild fauna ^[27][28][29,53]. This zone comprises two units. The first unit is protection and conservation. Although it has a natural vegetation cover, it is unsuitable for agricultural purposes, as it presents very severe limitations, such as rocky outcrops, high hills with steep slopes, etc. Its use would correspond to the protection of watersheds and wildlife, recreational purposes, and others that imply some collective benefit or social interest ^[29][54]. The second unit is forest production. It is the group land that is not suitable for any agricultural activity, being relegated to forestry exploitation and production. Regarding the zone of moderate-risk and ecological protection, this unit is considered as a livestock exploitation zone. The use of these lands should be oriented toward the conservation and protection of natural resources, with emphasis on the preservation of the vegetation cover, essential to controlling natural erosion processes, as well as for the promotion of the regeneration of the natural vegetation of the area. Finally, the low-risk and ecological protection areas, due to their characteristics, can be used for agricultural activities, also for other uses following social interest policies, under the principles of sustainable use ^[29][30][54,55].

3. Activities for the Conservation and Protection of PPF Buffer Zone

Since the main objective of the BZs is to minimize the negative impact of human activities within the PNA, the activities and uses of these areas must be subject to strict regulations that avoid putting them in danger. In this way, the conservation of natural resources is ensured, and the protection of many ecosystems is safeguarded. In addition to the water resources provided by these areas. From the point of view of environmental conservation, in the areas where it is possible to install crops (0.82% of the BZ), importance should be given to native or introduced species adapted to the ecological zone ^[30][31][55,56]. These are essential to establishing socio-economically and environmentally sustainable agriculture ^[32][33][42,57], on land suitable for permanent crops that are not suitable for periodic and continuous soil removal (15% of the BZ). It would be convenient to install permanent crops (herbaceous, shrubby, or arboreal) as well as forages, under economically accessible techniques for local farmers without deterioration of the productive capacity of the soil or alteration of the hydrological regime of the basin ^[29][30][54,55]. In the areas of livestock use, 30% of the BZ (P3se, P3se(t)), it would be convenient to produce natural pastures or cultivated with direct sowing, correcting the low fertility with the use of organic matter, which allows continuous or temporary grazing without deterioration of the soil resource, taking advantage of the residues of the agricultural exploitation. It is also convenient to use controlled or rotational grazing practices to avoid soil compaction (especially in the rainy season), in this way, the soil is left to rest, and the regrowth of the meadows is improved. The forestry production areas, 31% of the BZ, due to the fragility of the soils (steep slope, texture, weak structure, low content of organic matter), group together those lands that, due to their severe limitations, are not suitable for any type of agricultural activity, by fundamentally relegating to forest use and production. They require complex conservation practices, such as the planting of tree and shrub species (following the contour lines), and the planting of live barriers to control soil erosion. These living barriers will protect the soil from climatic phenomena and help retain the sediments from being washed away by rains, favoring the protection and conservation of biological diversity, without forgetting the revegetation of slopes to maintain soil stability and geological structure, and other practices that researchers indicate in soil and geological structure, seeking, as far as possible, a better use and management of these resources under the physical reality of the environment, avoiding deforestation ^{[29][30][31][34]}[54,55,56,60]. The conservation of its biodiversity and the mitigation of the negative impact of climate change will depend on the protection of forests. Native species plantations should be preferred to exotic plantations, due to their inherent capacity to host biodiversity ^{[17][22][35][36]}[17,22,61,62]. Planting native species ensures that they do not disappear, their study being necessary for optimal use of resources ^[17][37][17,48]. The protection and conservation zones (24% of the BZ) group the lands that are characterized by their very severe to extreme limitations (climatic, edaphic, topographic, etc.), which are inappropriate for agricultural purposes and even for forestry purposes, and their use is not economic and they should be managed for the protection of hydrographic basins, wildlife, research, etc. On Hillsides and areas with steep slopes, it is important to implement the installation of live barriers at contour lines using native forest species ^{[3][29][31][34][38]}[3,54,56,60,63].

4. Why Is It Important to Maintain the Montane Forest Ecosystem in the PPF

The Tropical Montane Forests (TMF), particularly the humid ones (Tropical Montane Cloud Forest), are home to the highest concentration of species with restricted distribution areas in South America ^[39][40][64,65]. This characteristic is manifested in the high number of flora and fauna endemism ^[27][41][42][29,66,67]. The conservation of the montane forests of the tropical Andes is a priority, due to their great biodiversity and high level of endemicity ^[37][42][43][48,67,68]. However, they are one of the least known and most threatened ecosystems in the tropics ^[36][44][62,69], because of high rates of deforestation and degradation. The ecological research works on these forests are fewer at the national level ^[36][62] and scarce at the regional level ^[45][70]. Within the PPF, researchers have the Tropical Montane Cloud Forest (TMCF) and the Tropical Lower Montane Cloud Forest (TLMCF). They are unique ecosystems that host a wide variety of highly specialized organisms, often adapted to foggy conditions ^{[37][39][40][42][46][47][48]}[48,64,65,67,71,72,73]. These forests comprise a complex of physiognomically different biological forms. It is dominated by trees between 6 and more than 35 m tall and undergrowth with an abundance of lichens, mosses, and herbaceous plants ^[27][29]. The main water inlet is the precipitation, but also receives additional inputs by interception of fog and wind-borne rain. Vegetation is key in this process, with evergreen tree species helping accomplish this task ^{[17][27][39][40][46]}[17,29,64,65,71]. Zones are considered of utmost importance for providing hydrological services, which gives it a connotation of hydrological hierarchy ^[47][49][72,74].

5. Endemic Flora and Fauna Species That Protect the Montane Forests of the PPF

Of the 5509 plants species endemic to Peru, 948 are typical of the Department of Cajamarca, of which 296 endemic species are exclusive to this region and are the montane cloud forests, jalcas, and páramos of the PPF, which contain these unique genetic resources ^[27][37][29,48]. In addition, the PPF provides refuge to a total of 110 species of birds ^[27][29]. Of these species, 29 are registered as CITES II type species. An endemic species of the Andes has been found in a very vulnerable situation, the “bearded turkey” Penelope barbata, both for the IUCN (2017) ^[50][75], and for the Wild Fauna and Flora Protection laws (Supreme Decree 004-2014—MINAGRI) ^[51][76]. Among the species of mammals in danger of extinction to consider, are the “puma” Puma concolor, the “Andean tapir” Tapirus pinchaque, the “tiger” Leopardus pardalis, the “spectacled bear” Tremarctos ornatus among others.

6. Changes in Land Use Natural and Man-Made Threat

In addition to the danger of climate change, there are serious natural and anthropic threats that are affecting the ecosystems of the cloud forests ((TMCF and TLMCF), as well as the dry forest (TLMDF) of the PPF, such as the loss of habitats due to the illegal logging, burning, opening of bridle paths, itinerant agriculture, overgrazing, lack of good forest management and conservation, excessive hunting, and illegal trafficking of wild species. At this point, researchers must consider some highlights by establishing the criteria for zoning the study area, considering its ecological value, productive aptitude, and levels of vulnerability. A study confirms that the largest extension of the Pagaibamba Protection Forest corresponds to lands of very high and high vulnerability (>85% of the PNA and 54% of the BZ), and of high ecological risk. Areas located for the most part on mountain slopes, which present severe edaphic and topographic limitations, are not suitable for agricultural activities.