Research Article |
Corresponding author: Bayron R. Calle-Rendón ( brcalle@unal.edu.co ) Academic editor: Christoph Knogge
© 2018 Bayron R. Calle-Rendón, Flavio Moreno, Renato R. Hilário.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Calle-Rendón BR, Moreno F, Hilário RR (2018) Vulnerability of mammals to land-use changes in Colombia’s postconflict era. Nature Conservation 29: 79-92. https://doi.org/10.3897/natureconservation.29.28943
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Colombia, one of the most biodiverse countries in the world, is entering a peaceful period after more than fifty years of armed conflict. Due to land use changes resulting from this new situation, negative effects on biodiversity, including mammals are expected. We think that mammal populations will be more sensitive in municipalities where activities related to post-conflict will be carried out. In that order, we aim to: 1) identify which mammal species would be more sensitive and 2) identify the critical regions where there is higher richness of sensitive mammals. We used the distributions of 95 mammal taxa and calculated a sensitivity index by combining four factors: 1) the proportion of each species distribution within protected areas in relation to their proposed extinction thresholds, 2) the proportion within post-conflict municipalities, 3) the proportion of five types of potential land use in post-conflict municipalities and 4) the threat status of each species. Using this index, we drew a map of species richness for mammals classified at high-risk and very high-risk categories. Primates were the most sensitive group to post-conflict changes. Urabá and the region near to the Serranía de San Lucas were the areas with the highest richness of sensitive species. We suggest using primates as flagship species to carry out conservation schemes in the post-conflict era in programmes led by local farmers and former fighters who have been reintegrated into civilian life.
Armed conflict, biodiversity loss, flagship species, primates, protected areas
After more than 50 years of armed conflict in Colombia, the Government and FARC (Revolutionary Armed Forces of Colombia), the oldest guerrilla army from Latin America, signed a peace agreement in 2016. One of the central points in such agreement is rural reform (
Colombia is a megadiverse country (
War in Colombia has had both negative and positive effects on biodiversity. Forests from many areas were cleared for illicit crop plantations, mining and land grabbing for cattle ranching. In addition, terrorist attacks spilled oil causing pollution over vast areas (
In the current post-conflict era, many social and environmental changes are expected in Colombia (
We selected mammals from six orders (Artiodactyla, Carnivora, Cingulata, Perissodactyla, Pilosa and Primates) with known distributions in Colombia. Species distributions were downloaded from the IUCN Red List of Threatened Species (
We considered as post-conflict areas, the polygons retrieved from the Departamento Administrativo Nacional de Estadístca (
To identify the sensitivity of mammal species to post-conflict land use change, we calculated the proportion of its distribution that overlaps with post-conflict areas and protected areas. Additionally, we calculated the proportion of species distribution that overlaps with five main types of potential land use for Colombia, only within municipalities of post-conflict in QGIS software (2.14.8-Essen). Then, we developed a sensitivity index (S) for each species considering four factors:
where Ts is the threat status according to the classification of the IUCN Red List of Threatened Species (
As detailed information about population structure of each species across all the country is unknown, we therefore used the threat status (Ts) of the species as a proxy of extinction proneness since it is related to a quantitative measure of reduction in population size in a temporal scale and geographic range (
Considering that any place outside protected areas will be more vulnerable to changes in land use in the post-conflict era, it is expected that species with a higher proportion of their distribution within protected areas will be less vulnerable. Then, we considered each protected area as a ‘patch of habitat’ and that each species would need an amount of habitat (i.e. proportion of its distribution overlapped with protected areas) equivalent to its extinction threshold to maintain a population in equilibrium (
where pa is the proportion of the distribution of each species within national protected areas and et is the extinction threshold applied for the species considering its body weight.
We assumed that the greater the post-conflict area overlapped with species distribution, the greater the negative effect on the species. However, the effects will be more negative in municipalities where more people will return in the post-conflict era since this immigration process is a driver of environmental impacts in the post-conflict era (
where Aj is the proportion of a species distribution within the municipality i and disp is a factor associated with each municipality according to the number of displaced people (dp): disp = 0.7 (dp < 10,000), disp = 0.8 (10,000 ≤ dp < 25,000), disd = 0.9 (25,000 ≤ dp < 50,000) and disp = 1 (dp ≥ 50,000).
Peace agreements between the Colombian Government and FARC have a special focus on rural reform to carry out agricultural activities according to the potential land use (
where Aj is the proportion of a species within a type of potential land use j and lu is a factor associated with each land use according to the intensity of use: lu = 0.2 (conservation), lu = 0.4 (forestry), lu = 0.6 (agroforestry), lu = 0.8 (cattle ranch) and lu = 1 (agriculture).
Finally, we created a grid on a map of Colombia using squared cells of 0.1° (approximately 10.6 km). Then the species richness was calculated in each cell by overlapping all species distributions and considering that a given species was present if the cell occupancy was greater than 50%. We created two maps: one considering all present species and another considering only species classified at high-risk and very high-risk according to our sensitivity index to identify critical regions where negative effects on mammals are most likely. Both maps were designed using the SAM Software Version 4.0 (
We obtained spatial distributions of 95 taxa: 44 primates, 26 Carnivora, nine Artiodactyla, seven Pilosa, six Cingulata, and three Perissodactyla (see Suppl. material
Proportion of mammal species amongst six orders within each category of sensitivity in the Colombian post-conflict era. Non-risk (S = 0), low-risk (0 < S < 5), middle-risk (5 ≤ S < 10), high-risk (10 ≤ S < 15) and very high-risk (S ≥ 15).
Most sensitive (S ≥ 10) mammal species in Colombian postconflict areas and the contribution of each of the four factors to the sensitivity index (S). Ts: threat status; PAET: relationship between the proportion of the distribution of each species within national protected areas and its proposed extinction threshold; Post: proportion of the distribution of each species within post-conflict areas; PLU: proportion of the distribution of each species within a type of potential land use in post-conflict municipalities.
Amazon and some points from the Orinoco region (including the eastern side of the Cordillera Oriental) were the areas with greatest overall species richness, followed by the Serranía de San Lucas and the transition zone between the Caribbean and the Pacific region near to the Urabá Gulf (Figure
a Mammal species richness in Colombia considering the distribution of 95 taxa of six orders. b Critical regions (Urabá and Serranía de San Lucas) where negative effects on mammals are most likely considering only those species classified as high-risk and very high-risk in post-conflict era (S ≥ 10). Black polygons correspond to the 170 municipalities used as post-conflict areas and green polygons to protected areas.
Increased attention has been given to the effects of warfare on biodiversity in the last two decades and Colombia is one of the areas of special attention (
We found that post-conflict alterations in Colombia represent a threat to many mammal species and that primates are the most vulnerable group to such alterations. As forest dwelling animals, primates are highly sensitive to deforestation, as well as other animals such as the Baird’s Tapir, that also depends on closed canopy forests (
Other human activities, such as hunting, may increase the threats to some primate species. For example, four Atelids and the Central American Red Brocket, which are classified as high-risk species in our study, face known hunting pressure (
We found that areas near to the Serranía de San Lucas and Urabá gulf are the most critical regions since they host the largest numbers of mammals considered at risk according to our sensitivity index. Historically, some guerrillas in San Lucas imposed environmental restrictions for locals to preserve the area, such as prohibition of hunting and logging and they planted landmines to avoid mining and logging by foreign people (
The relationship between biodiversity and warfare can be separated in three stages: 1) preparations, 2) war and, 3) post-war activities (
Increasing the protected areas should be a government strategy associated with the rural reform to prevent biodiversity losses during the post-conflict period. The critical regions for the implementation of such protected areas would be areas near to Urabá Gulf and Serranía de San Lucas, since they harbour most of the high-risk species from this study. Most of the species classified as high-risk or very high-risk in our analysis have less than 10% of their distribution under legal protection. The most critical case was Plecturocebus caquetensis, the single very high-risk species in our analysis that occurs outside of the most critical areas in post-conflict: its distribution does not overlap any protected area, its entire distribution is within post-conflict area and it was recently classified amongst the world’s 25 most endangered primates (
Around the world, in the last half of the past century, more than 80% of armed conflicts took place within biodiversity hotspots (
When the environmental context is not cohesive with peace agreements, several drivers of environmental change can emerge (
This first evaluation of the possible consequences of the peace agreement between Colombian government and FARC on mammals can help to improve the current scenario of peace in Colombia. Fourteen species classified at high-risk or very high-risk categories need to be included in schemes for conservation based in local initiatives led by former fighters and victims of armed conflict. Experiences from Asia, Africa and Central America have shown how the lack of planning can have negative effects on biodiversity, since impacts on the environment increase after cessation of conflict or peace treaties (Loucks et al. 2005,
We are grateful to C. Murcia who made valuable comments on a first version of this paper, with X. Carretero-Pinzón who revised the final version in English and with the two reviewers who contributed to improve the manuscript. B.R.C.R. is supported by a PhD scholarship from the CAPES (Federal Agency for Support and Evaluation of Graduate Education).
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