Natural ecosystems are increasingly being affected by climate change and fragmentation, which have a strong impact on biodiversity thus affecting habitats and species diversity of flora and fauna at all levels. As a response to this situation the idea of biological corridors was developed.

This review relates the problems associated with the main concepts and definitions of the biological corridors, seeking to highlight the advantages of this tool and describing its potential applicability, and showing the importance of the biological corridors as a solution to improve the conservation of species and so as to support sustainable development in areas of high biodiversity. Examples of biological corridors in several countries are cited and its application guidelines and conservation benefits are described.

In conclusion, the need to improve information on habitat and its association with wild species is highlighted through adaptive forestry that is part of a comprehensive management of forest ecosystems. In addition, it is important to monitor the effects of corridors implemented in a feedback process that allows a greater analysis and evaluation of the overall positive effects of their implementation. Finally, some management actions are proposed to improve the conservation of ecosystems.

Ecosystem management, biodiversity conservation, biological corridor, sustainability

Human development has been changing, destroying and simplifying the coverage of the planet, splits and reducing the area of natural habitat and, consequently, transforming the landscape into a mosaic of human settlements, agricultural land, or isolated fragments of remaining forests (Bennett 1998, Morera et al. 2007, San Vicente and Lozano 2008).

Another factor in the degradation of natural ecosystems is climate change, which will cause a change in the distribution of ecosystems and species (Locatelli and Imbach 2010), especially forests, which play an important role to mitigate climate change by acting as ‘sinks’ that absorb carbon from the atmosphere, by storing it in biomass and soils: However, when they are cleared or degraded, they are also a major source of emissions of greenhouse gases (FAO 2013, Romijn et al. 2015).

All mentioned above leads deforestation to be considered as a serious environmental problem worldwide. Data are clear: while in 1990, the world had 4128 million hectares (ha) of forest, in 2015 that area had decreased to 3999 million ha. This means a change from 31.6% of the global area being ​​forest land in 1990 to 30.6% in 2015. Africa and South America experienced the highest net annual loss of forests between 2010 and 2015, however the loss compared with the previous 5 years has been mitigated (FAO 2015).

Besides the loss of forest area, the remaining forests have been intensely fragmented. It is known as forest fragmentation interruption of continuous forest area into smaller fragments with varying degrees of isolation, due to anthropogenic, natural factors and especially forest fires (Bustamante and Grez 1995, Wilson et al. 2005, San Vicente and Lozano Valencia 2006, Cagnolo and Valladares 2011, Herrera et al. 2011) affecting the habitat of wildlife species which depend on these ecosystems (distribution, abundance). All this implies a decrease in natural habitat (Hobbs 1993, Bennett 1998, García 2002, Uezu et al. 2005).

When the area of natural habitat decreases, both richness and abundance of wildlife species are reduced consequently, and the rate of local extinctions increases (Bennett 1998, Steiner and Köhler 2003, Bustamante et al. 2005) as it is the case of temperate forests´ fragmentation affecting diversity and abundance of birds living in those ecosystems (Willson et al. 1994, Sieving et al. 2000). Similarly, the isolation can reduce exchange of individuals between populations from different fragments (San Vicente and Lozano 2008) of species that require continuous forests at different altitudes (Primack et al. 2001).

In the management of forests, adjacent or nearby protected wild areas are rarely under a common management plan that makes their protection more effective. (De Graaf et al. 1998, Puth and Wilson 2001, Graf et al. 2005). For these reasons, maintenance of land as reserves of natural resources and biodiversity is a key management objective and a prerequisite for sustainable forestry, since it is necessary to understand the dynamics and heterogeneity of natural forests to provide management guidelines (Lindenmayer et al. 2000, Franklin et al. 2002), like those included in several treaties that promote the implementation of activities to ensure the conservation of biodiversity, such as the Montreal Process and the Seminar of Experts on Sustainable Development of Temperate and Boreal Forests, which mention Criteria and Indicators for the Conservation and Sustainable Management of Temperate and Boreal Forests.

In order to contribute to the solution, or at least to prevent large losses of biodiversity conservation, an alternative called “biological corridors” was proposed by Wilson and Willis in 1975. Biological corridors have since then become an interesting option to face the problem of degradation and detriment of global biodiversity. The creation of biological corridors is so intended to be the basis to meet multiple objectives such as biodiversity conservation and use of all ecosystems´ environmental services, allowing the natural resources management to be integrated with such conservation (Gilbert et al. 1998, Pardini et al. 2005, Schmiegelow 2008, Moreno et al. 2011, Cushman et al. 2013). However, the concept has been used interchangeably with the use of land and its management. The objective of this review is to propose the different approaches of biological corridor that are found in scientific literature and contribute to improve research in forest conservation and management.

The review presented here shows the positive value of biological corridors as a tool for sustainable land management that seeks to ensure the conservation of biodiversity in forest ecosystems.

The main conclusions of this study were: (i) Though biological corridor is a relatively modern concept, many definitions were found, depending on their objectives, scale, and contextualization, (ii) the achievement of the biological corridors goals should imply to make a correct diagnosis of the current situation of the factors involved in the territory to preserve, (iii) the mere protection of areas, within the frame of any biological corridor´s design, will not solve, by itself, the problem if the corridor ultimately does not fulfill its functions, including the sustainable use of its resources, (iv) the effectiveness of a biological corridor is not only due to its design, but mainly to its proper functioning, framed in plans and programs of different scope and scale on a wide territorial basis, (v) it is necessary, with the aid of adequate indicators, the monitoring of the results so that the strategy of biodiversity conservation is continuously fed-back.

Regarding the main gaps in the literature, we have noticed lack of forest management through an adaptive silviculture as an option to meet conservation and development since in protected areas like those interconnected by biological corridors, forest management can help to accomplish both ecological and social economic development through the implementation of flexible silvicultural programs adapted to legal and biophysical conditions.

We also appreciate the advice and assistances in the edition of this article of Christian Casabón, Vanessa Guerrero.