1. Purpose and concept of buffer zone
According to Van Orsdol (1987) in traditional application, buffer zones are designated to achieve three main objectives:
1. Contribute to the genetic conservation, species and diversity of ecosystems in areas of particular scientific, biological and cultural importance;
2. Provide research, monitoring, and training opportunities;
3. Promote sustained development around Protected Areas.
Miller (1980) considers that the buffer zones seek to protect the wild area from different harmful effects and must be able to absorb chemical and physical disturbances such as air, water or soil pollution, poaching, uncontrolled tourism and noise.
When applying this concept, the following is taken into account:
1. The need to stop the effects of the most intensive activities within the protected natural area on other zones of the same area; that is to say, damping is a function between each of the internal management zones, rather than one zone itself (figure No. 1);
2. The need for a strip that stops the effects of external activities towards the protected natural area (external buffer).
However Mackinnon, cited by Oldfield (1988), defines buffer zones as areas on the peripheries of natural protected areas, which have restrictions on their use to provide an additional band of protection to the protected area and compensate members of the communities settled in the buffer zone due to the loss of access to the protected natural area.
Since 1982, at the National Parks Congress in Bali, Indonesia, the concept of buffer zones around protected areas has taken a more integrated approach since it was considered that natural resources cannot be located far from populations and that many of the Problems associated with protected natural areas currently represent management problems that integrate the protected natural area with the development needs of the local population.
The buffer zone must manage under the concept of sustainable development, the concept adopted by the Central American Alliance for Sustainable Development ALIDES being the following… ”Sustainable Development is a process of progressive change in the quality of life of human beings, which places as the center and primary subject of development, through economic growth with social equity and the transformation of production methods and consumption patterns and which is sustained by the ecological balance and life support of the region:
This process implies respect for regional, national and local ethnic and cultural diversity, as well as strengthening and full citizen participation, in peaceful coexistence and in harmony with nature, without compromising and guaranteeing the quality of life for future generations. ”.
Based on this knowledge, the need to seek sustainable development in the buffer zones is highlighted, where the needs of the local population are taken into account and not only managing this area as an animation of the protected natural area.
2. Determining factors in the establishment of buffer zones
To determine the type and extent of the buffer zone the following factors should be considered (Mackinnon 1986):
1. Threat to wildlife species that occasionally inhabit the limits of the reserve; knowledge of the size of the population and habitat of the species could be some indicators of an adequate extension;
2. The possibility of buffer zones to serve other protection functions such as soil and water conservation or protection as a firefighting belt;
3. Conservation of wildlife species that are likely to be found outside the protected natural area;
4. Reasonable need of the local population for land, forest products, grazing or agricultural areas;
5. The availability of land whether it is with natural cover or other vegetation, or that it is abandoned or begins to be used;
6. The possible substitution of buffer crops for a particular type of land and climatic conditions and the interests of wildlife.
The author himself considers that, as a general rule, the priority level should be the need for protection; followed by the need to harvest products for direct consumption by farmers and finally the development of cash crops.
As can be seen, the needs for the establishment of the buffer zones refer to the conservation and protection of the species, the available land and the aspirations of the farmer to satisfy his basic needs.
3. Functions of the buffer zones
For Mackkinnon (1986), the buffer zones must fulfill the following functions:
1. Allow an increase in wildlife populations through an extension of the buffer: the habitats contained in the reserve area allow the possibility of breeding and survival of plants and animals that otherwise could only survive in the protected area;
2. Promote a use product with value for local people: wildlife in the buffer zone is of secondary importance and land use is not in conflict with the objective of the protected area;
This generally involves planting species that are attractive habitats for local wildlife or allowing harvest control over wildlife.
In this case, rural residents do not have to search for products (firewood, wood, for construction and others) within the reserve.
4. Benefits of buffer zones
Oldfield (1988) considers that the potential benefits of the buffer zones are many and very varied (depending on the management techniques applied) since they favor both the biological resource and the human population.
4.1 Biological benefits
1. Provide additional protection, from human activities, for the strictly protected nuclear zone;
2. Protect the heart of the protected natural area from biological changes;
3. Provide additional protection from severe damage caused by natural or anthropogenic causes;
4. Provide a forest unit for conservation with less loss of species through the edge effect;
5. Increase in habitat and thus a larger population size, wide range of species;
6. Allow for many natural limitation related to the movement of species;
7. Provide a supply zone for species in the nuclear area;
8. The presence of trees minimizes changes in the local climate and provides shelter for annual and permanent crops;
9. The presence of trees helps to enrich the fertility of the soil and to maintain its structure;
10. The presence of trees helps prevent soil erosion;
11. Trees provide habitats for wildlife.
4.2 Social benefits
1. Local people maintain access to species of flora and fauna traditionally used;
2. Villagers are compensated for the loss of access to strictly protected nuclear areas;
3. Local people participate in the conservation of the protected area;
4. There is more land for education, recreation and tourism;
5. Wildlife conservation becomes part of local and regional rural development plans;
6. Traditional land rights are safeguarded towards local inhabitants;
7. Increase jobs related to conservation;
8. The extension of the diversity and seasonality of farm products increases the stability of the farm system;
9. Local collection of products, wood, food and medicine, from trees, reduces the need to transport or buy them.
10. The economic guarantee is obtained by storing the salable wood;
In addition to the above benefits, there are others related to the sustainable management of natural resources, related to biological and social benefits. Among these benefits the following can be distinguished:
- Water quality; Stability of the hydrological regime; Sustainability in the natural factors of production; Improvement in the level and quality of life of the population.
According to Oldfield (1988), in order to achieve the benefits described, the following basic criteria must be observed:
- Tree cover and habitats should be maintained as much as possible in their natural state; The vegetation of the buffer zones should resemble the protected area, both in species composition and structure; The buffer zones should possess as much biological diversity as possible. possible; The physiognomy of the vegetation should be as heterogeneous and stratified as possible; The capacity of the ecosystem in the buffer zones to maintain the recycling of soil nutrients should be maintained as much as possible. The activities of the buffer zone should not have a negative impact on the physical structure of the soil or on the capacity of water regulation; The exploitation of the buffer zone should, as much as possible, make use of tradition,Population lifestyles and locally adapted resource management practices.
The above criteria, in general terms, are manifested towards an extension of the protected area, which makes it difficult to reconcile these criteria with the achievement of the proposed benefits.
5. The buffer zone and its function in the context of biological corridors
5.1 Fragmented and loss of natural habitats
Currently, there is greater concern about the effects of the loss and fragmentation of natural habitats, and at the same time, there is greater awareness of the need to take practical steps to maintain and restore connectivity in order to promote the biological viability of isolated wild populations (Bennett et al. 1994; Lambec 1997).
The alteration of a natural habitat does not only include the direct and physical conversion of a natural area to anthropogenic (habitat destruction), for example when a humid forest becomes a pasture; it also includes the breaking of a large and continuous habitat patch into smaller patches (habitat fragmentation) and changes in the composition, structure or function of an ecosystem (habitat degradation) (Noss et al. 1997).
The destruction and degradation of natural habitats are widespread and its implications for the conservation of biological diversity and the sustainability of natural resources are of global significance. Where habitats are not completely destroyed they are fragmented into small patches, originating "isolated from habitat in a" sea of development "(Turner 1996; Alonso et al 2001).
All indications are that habitat fragmentation has severe effects on population viability even when management attempts to eliminate the invasion and introduction of exotic species or other threats to species in fragmented habitats (Burker 1988).
Fragmentation refers to the division of a continuous habitat into smaller, more isolated patches, the result of which is the reduction of the total area of habitat (loss of habitats), the reduction of the size of the habitat patches and the increase in isolation (Saunders 1991; Hobbs 1993; Fahrig and Merriam 1994; Ecotono 1996).
By reducing the total area of the habitat, consequently the population size decreases and the local extinction rate increases; in addition, the remaining area that is fragmented limits the rates of dissemination and immigration (Guevara 1995).
The effects of habitat loss and fragmentation can be noted at various levels of biological organization and include changes at both the genetic and population levels (Meffe and Carroll 1997). Such effects influence the dynamics of a population of at least four types of species:
1. species sensitive to isolation, affected by the dispersal barriers created by the new habitat matrix with different structure and composition; 2. Species sensitive to the size of the area, with requirements for large areas; 3. Species sensitive to physical and biological changes related to edges; 4. Invasive species that disperse and colonize the new habitats created in the matrix (Ecotono 1996).
The fragments may lack a representation of all the habitats of the original block, leading to a loss of heterogeneity, which can affect species that require different habitats (Carrillo 2000). The process of habitat reduction and fragmentation also alters ecosystems by changing ecological processes (Peck 1998).
The combination of these changes reduces native biodiversity and this trend is currently considered one of the main causes of species extinction (Noss 1987; Hudson 1991; Guevara 1995; Turner 1996; Meffe and Carroll 1997; Noss et al, 1997; Haddad 1999).
Habitat alteration is considered the main factor threatening species and ecosystems (Noss 1987; Hudson 1991; Guevara 1995; Turner 1996; Meffe and Carroll 1997) and the fragmentation of humid tropical forests one of the most direct causes of loss of biodiversity (Meffe and Carroll 1997; Alonso et al 2001).
Fragmentation generally results in land consisting of remaining areas of native vegetation surrounded by a matrix of agricultural land (buffer zone and influence) or other forms of land use. Remnant can be defined as a patch of native vegetation around which all or most of the original vegetation has been removed and because of this, they are sometimes called habitat islands. So-called habitat patches, on the other hand, are areas in the landscape that are functionally defined for a particular species that can be used for breeding or feeding (Saunder 1991; Fahrig and Merriam 1994).
The isolation of the remaining areas has important consequences for the biota (Hobbs 1993; Bennet 1998), which vary with the distance to other remnants and with the degree of connection between them. Natural remnants increasingly occur as a mosaic of large patches that can be considered natural reserves and small surviving patches surrounded by types of intensive land use (Bennett 1998).
The spatial structure of the landscape, which consists of the spatial relationship between patches of habitats and the matrix in which they are immersed, is of central impotence for the compression of the effects of fragmentation on the survival of populations.
This spatial relationship controls the present functions (flow or movement) and temporal changes. Some of the characteristics of the spatial structure of the landscape are: 1. the size, shape and warmth of the patches; 2. witness dispersal routes through the landscape; 3. the quality of the dispersal routes; 4. the spatial configuration of the components of the landscape. The recolonization of local extinctions is critical to the regional survival of fragmented populations.
Endangered species are typically restricted in their dispersal range and in the types of habitats through which they disperse. Conservation of large tracts of remnants of tropical forest is essential to protect a wide range of species of which the extent of the habitat exceeds the limits of the reserves.
For these, factors such as the spatial relationships between the elements of the landscape and the dispersal characteristics of organisms are fundamental considerations for decision-making. For many populations, survival on a regional scale depends on the recolonization of these local extinctions from other areas by dispersal (Fahrig and Merriam 1994, Alonso et al 2001).
In fragmented landscapes, the inhibition of the exchange of individuals leads each population or subpopulation within each forest remnant to isolation, favoring that it is more susceptible to local extinction, due to effects, favoring that it is more susceptible to local extinction, due to genetic (inbreeding, for example), demographic (eg, temperature fluctuations, in predator and prey populations). The reduction of the total availability of the habitat (Carrillo, 2000) and access to the basic resources required by the species also play a role. The reduction of immigration leads to reproductive isolation and is among the six extinction mechanisms in fauna. Also, by not moving between shards,many animals can restrict the migration of plant species that depend on their seed dispersers and can restrict the gene flow of species that depend on pollinators (Turner 1996).
Based on this, one of the greatest current challenges is to maintain and conserve the biodiversity that is threatened by the accelerated process of fragmentation, loss and isolation of natural habitats caused by human disturbances. The fragmentation effects can be mitigated by means of some measures that include the reduction of the impacts caused by the land uses of the environment, improvement of the quality of the existing habitats, increase of the effective area of the habitat and the increase of the connectivity that allows migration between fragments or reserves and thus delay extinction (Burkey 1988).
Increased connectivity can be achieved by identifying and evaluating opportunities for the maintenance, restoration or revegetation of wide habitat corridors or other forms of functional connectivity between natural areas, to contribute to the conservation of biodiversity, before these are lost and reserves are completely isolated (Hobbs 1993; Meffe and Carroll 1997; Bennet 1998).
5.2 Loss of connectivity
Connectivity, the opposite of fragmentation, has become one of the best accepted and fundamental conservation principles for the development of nature reserves, buffer zones and zones of influence.
Few conservationists disagree that local populations functionally connected by natural movements are less susceptible to extinction than populations isolated by human activity (Rosenberg et al 1997; Soule and Terborgh 1999). The term connectivity, created in 1984 by the ecologist Gray Merriam, refers to the “ability of a landscape to maintain the movement of organisms, genes, materials or energy, since, in general, the concept is mainly related to the movement of species".
Connectivity involves the linking of habitats, species, communities, and ecological processes at multiple spatial and temporal scales (Noss 1991) AND GENES BETWEEN HABITAT PATCHES. I could also refer to the extent to which a corridor is spatially continuous or connected (Forman 1995). However, it is a relative idea, which depends on the process or species in question (Peck 1998).
Two main components influence the potential connectivity for a particular species, community or ecological processes: the structural one (spatial configuration, presence and extension of gaps and alternative routes, distance between patches, among others) and behavior, which is the response to the physical structure of the landscape by the organism (degree of specialization to the habitat, tolerance to disturbances, among others) (Bennet 1998).
However, connectivity is nothing more than conservation objectives, instead it is the natural state of things, since nature was originally connected to the continental scale, separated by natural barriers. Since the development of agriculture, the vegetation cover of the entire continent, except Antarctica, has been extensively modified (Saunders 1991). Proponents of landscape connectivity (eg Reed and F. Noss), in general, and wildlife corridors, in particular, sometimes regress to the naturalistic premise that the natural situation of the pre-agricultural world it was connectivity and not fragmentation (Mann and Plumier 1995).The most significant anthropogenic effects on biodiversity have caused changes in landscape connectivity and their existence is essential to maintain the viability of wild populations in landscapes (USDA), especially when it comes to fauna species that require large natural forested areas (Turner 1996). Furthermore, connectivity maintains or restores ecological processes that have been disrupted by human activities (Noss 1991; Soule and Terborgh 1999; Rosernberg et al. 1997).Rosernberg et al. 1997).Rosernberg et al. 1997).
For this reason, it is that by restoring connectivity, consequently, the impacts of agriculture or development are being repaired, although, in some cases, the imposition of connectivity or restoration may be more damaging than fragmentation.
There is a growing need to use design criteria to improve conservation systems or networks in fragmented areas, but that requires a clear understanding of the problems created by fragmentation (Saunders et al. 1991). Maintaining landscape connectivity has also become more important among major forest management issues (SFMs), where activities, such as logging, have the potential to remove species from cleared areas, fragmenting and isolating populations (Margules nineteen ninety six).
5.3 The implementation of biological corridors in the buffer zone
Morales R. (2002), argues for more than a decade that the most viable option for the implementation of biological corridors in the buffer zone and influence of protected natural areas, should be the causes of rivers, streams and / or ravines, The preservation of the gallery forest adjacent to the channel is characteristic of said areas.
Under the Morales R. operational concept, the biological corridors in the buffer and influence zones combine two relevant factors that may allow the viability and functionality of the mimes, the existence of forest cover through the gallery forest (generally rich in tree species). nutrices) and the continuous or temporary presence of water, allows to fulfill the main objective of the implementation of a biological corridor "to increase or maintain the biological and ecological viability of species and populations, by increasing their persistence in the habitat and in the region".
At the same time, execute compatible development actions that promote the development and sustainable management of the natural resources existing in the buffer zone and influence such as: 1. implementation of forest management plans; 2. agroforestry; 3. agrosilvopastoral systems; 4. agricultural diversification; 5. zoociraderos and 6. soil conservation.
With the communities, it will strengthen the function of connectivity and socio-productive development, considering that the implementation and management of biological corridors takes place within a political and social context, considering itself extremely complex, requiring an integrated strategy to preserve its value for the conservation of the biodiversity and food security of communities.
Its management may be based on the best information available, but it is a social exercise, which requires land to provide biological viability.
Corridors, like any biodiversity conservation strategy, have different assumptions, advantages and disadvantages. In practice, the effectiveness of its establishment is questionable if the basic needs, aspirations and social and cultural specificities of human communities are not known, incorporated and respected, as key elements in the conservation equation to guarantee sustainability.
Based on this, the strategy must incorporate the socioeconomic component of the populations living in and around a corridor and the adjacent protected areas (Incer 1995).
According to Bennett (1998), social, cultural, economic and political elements, such as land status and tenure, are very important. Acceptance and support of the local community. The guidelines and standards should not only be sustained in biological aspects, but socio-economic and political aspects should be integrated (Bermúdez 2000).
Biological corridors are almost always located in buffer and influence zones, being unprotected areas and vulnerable to development and activities that are destructive to wildlife and ecological functions. Its effectiveness may be affected and its persistence compromised by the type, proximity and extent of human activities, as well as by the land use practices developed, both within and adjacent to the corridor, although ideally, this should be protected and be able to counter threats to biota.
There may be cases where the high priority of connecting populations of threatened species is not justified when, in fact, their decline is clearly due to hunting or other direct causes, which are not related to the isolation and fragmentation of their habitats (Bennett 1998).
The acquisition of marginal habitats to form corridors may have a lower priority in relation to the preservation of isolated areas that contain endemic or threatened species (Noss 1987). Other than that, it becomes quite difficult to maintain vegetation remnants when adverse impacts caused by management practices in their environment continually impact (Saunders et al. 1991). There are few initiatives to define standards for the management of a biological corridor, including some land use prohibitions that prevent the area from functioning as a corridor (Beier and Loe 1992).
As with buffer zones, for a corridor to have conservation value, land uses must be consistent with the region's conservation objectives.
Compatible uses are those that do not interrupt processes, such as the nutrient cycle, key biological interactions between species, or reproduction; they are uses that do not compromise the integrity of ecosystems or the viability of populations. It is not possible to establish biological corridors between protected natural areas without involving the settled communities in the buffer and influence zones, since these can guarantee sustainable management. The complex mosaic of institutions, cultural, human activities, has to be inserted into the mosaic of nature with its interactions. Rural populations adjacent to national parks should be integrated into conservation decision-making, including the proposed corridor establishment (Mwalyosi 1991).Various stakeholder groups have different perceptions and interests in conservation policies and actions. These actors, together with their interests, perceptions and needs, must be defined and taken into consideration in a conservation strategy outside protected areas (Halladay and Gilmour 1995).
In order for conservationists to encourage friendly behavior among those who live in and use buffer zones adjacent to nuclei and corridors, positive incentives become very important. These exist in a wide variety, with the purpose of encouraging the participation of diverse groups and individuals in the implementation of buffer zones and biological corridors (Shafer 1999; Soule and Terborgh 1999).
Government conservation policies can cost less for society and be more effective for conservation when they allow landowners to choose to receive compensation for their conservation efforts instead of imposing the same criteria (CI / IESB 2000). Environmental services benefit the owners and neighbors of the forests or other ecosystems that produce them, and also society in general. With the incentive towards the production of these services, owners feel more motivated to participate (Oliver et al. 2001- Simpsiuo summary) and the greater will be the will to conserve the ecosystems that produce it (Garcia 2000).
For example, to implement a corridor, an environmental services expansion program could be proposed as the main means. These services include water, in quantity and quality required, erosion control, disaster impact reduction, biodiversity conservation, greenhouse gas fixation, or others. The benefits and services to the communities and society, in general, contribute to making the strategy represented by the corridors viable.
On the other hand, it is observed that the purchase of land in the buffer and influence zone has been the main mechanism to vitalize the establishment of biological corridors. Land acquisition plans within a corridor are part of a strategy to resolve conflicts of use of resources, which should not be the only alternative, when there are other mechanisms (Varea and Rodríguez 2000), such as, the legal, of private conservation, that do not necessarily imply in the purchase or expropriation.
Conservation benefits are an important part of the political strategy to be used when there is a complex tenure situation. It is important that people have access to these benefits. Incentives for conservation can be provided through collaboration so that the owners get the title of their properties and being the owners of the resources, from there the attitude change is promoted.
