How deforestation and degradation of forests in the southern Orinoco affects the survival of the Harpy Eagle

EXPLORA Magazine. Second Special Edition. 2021.


The harpy eagle and the Amazon rainforest can be described as giants of nature. The harpy eagle (Harpia harpyja) is the largest eagle in the Americas and the most powerful in the world, living in the tropical forest of south and Central America. The tropical forests of the Guayana region and the Amazon basin are considered the largest in the world, extending through nine countries in South America, including Venezuela, and occupying approximately 5,500,000 km2. That represents 56% of all broadleaf forests on the planet. These forests are considered the most important ecosystems for the global conservation of the harpy eagle and many other species of vertebrates that are interconnected by the roles they play within their environment.

In global terms, the harpy eagle probably has a population in the range of 20,000 to 40,000 individuals throughout its habitat, with an estimated 3,500 individuals in Venezuela of which approximately 2,450 are found in the region of Guayana and the Orinoco river basin.  Therefore, Venezuela hosts a very important population within its range of distribution in the Americas.

Both the harpy eagle and the forests south of the Orinoco are threatened. The eagle has disappeared from many areas within known historical habitats, caused mainly by the loss of thousands of hectares of forest. The harpy eagle, the forests of the Guayana region and the Orinoco river basin, face great conservation challenges.

It is not currently considered an endangered species on a global scale. However, harpy eagle populations are suspected to be declining and their range is narrowing. The International Union for Conservation of Nature (IUCN) includes the harpy eagle as a «Near Threatened» species worldwide in its Red List. In Venezuela, it is classified as «Vulnerable» according to the Red Book of Venezuelan Fauna.  In addition, this species is declared in Venezuela as Prohibited for Hunting (Decree MARNR 1485) and in Danger of Extinction (Decree MARNR 1486) according to national resolutions since 1996. These Venezuelan lists place the harpy eagle inside categories of more serious threat than the IUCN’s List Red. The inclusion of the eagle in these lists has a very important meaning since the crimes contemplated in the Organic and Criminal Environmental Laws impose severe legal penalties and sanctions, for attacks on rare or endangered species.

The harpy eagle is estimated to suffer a 27.6% to 45.5% habitat loss and the species is likely to decline between 25% and 30% over the next 30 years. Because the harpy eagle is naturally found in low densities and reproduces slowly (reproductive cycles of 4 years on average), then a small decrease in the annual survival rate of adult birds can have a large effect and negative impact on population size. Large bird species with slow reproductive rates are highly susceptible to habitat loss. Therefore, the population and distribution trends of the eagle warrant concern and appropriate and timely responses from a conservation standpoint.

The most important human threats include the capture of live eagles as trophies or for trafficking and illegal possession.  Hunting is also driven by an ill-founded retaliation for attacks and losses of domestic livestock. Even the curiosity on the part of people who have never or rarely seen this large eagle, has been recorded as a motive to kill them.

Historically, the forests south of the Orinoco have been largely inaccessible, and for many years these forests remained with little intervention and were relatively immune to the destructive activities of human populations for many decades. Human access was originally largely limited to transportation along rivers. However, in more recent times, this region has become vulnerable to deforestation and degradation. In the last 20 years, more than 5,265,000 hectares of forest have been lost. Some of the main causes for deforestation include the advancement of agricultural interests, such as the acquisition of land for extensive cattle ranching and large scale crops. Other reasons for deforestation are the construction of roads (opening vast new areas to human exploration and exploitation), the establishment of new human settlements, logging, and also illegal mining.

These situations have triggered different conditions that affect the biological and ecological cycles of the harpy eagle, related to:

1. Loss or drastic reduction of the eagles’ territories.

2. Loss of vegetation cover that allows to house a large number of vertebrate species, that in many cases represent food for eagles and, on the other hand, fulfill ecological functions related to the maintenance of forests.

3. Loss of timber tree species, which are mostly of high commercial value, but are also the emerging or larger trees within the forests, and which are used by these eagles to make their nests.  These timber tree species are also the essential building blocks for the eagles’ life cycle.

4. Landscape modification, exposing the eagles and their nests to steep environmental changes.  That includes drastic increase or decrease in temperature and humidity, greater exposure to the effects of solar radiation, winds, rain, and other weather factors.  Those changes directly influence their reproductive cycles, rearing, survival of chicks, juveniles, and sub-adults.

5. Noise and motor vehicle traffic disturbances for those nests that are exposed on the  forest edges, logging and mining yards, paddocks, routes of mining, timber, agricultural and livestock penetration; All these also negatively affect the continuity of the reproductive cycles of eagles.

6. Increase in human conflicts due to eagles. This is the consequence of introducing domestic animals within the historical territory of eagles, where they are unjustly accused for the loss of animals.

The conservation status of the harpy eagle in the face of the threats it faces, confirms a key premise to further implement the legal protection of Venezuelan biodiversity in general. It is clearly denoted that effective legal protection for wildlife requires a double approach, which contemplates effective legal protection of habitat, and species of fauna in a comprehensive manner. A legal intervention on behalf of a terrestrial vertebrate species is unlikely to be successful in the long term without effective habitat protection.

How difficult habitat conservation can be is clearly demonstrated in the struggle to determine a safe and legally protected future for the forests south of the Orinoco. The legal protection of the habitat must be complemented with more specific legal provisions for multiple species, populations and communities of terrestrial vertebrates that protect them against threats.  Such threats encompass hunting, capture, trafficking and illegal possession, in addition to the constant anthropogenic impacts to which the ecosystems are subjected as those threats cause loss and degradation of habitats.

The importance of conserving the forests south of the Orinoco for the survival of the harpy eagle and multiple terrestrial vertebrates should be evident, according to the current legal framework on environmental matters in Venezuela. The eagle plays a key role in the ecology of tropical forests in the Guayana and Venezuelan Amazon region as an apex predator. Removing the eagle from these ecosystems could negatively impact ecological health in unforeseen ways. The harpy eagle, like other neotropical raptors, serve as sanitarians and natural controllers of many populations of terrestrial vertebrates, helping to keep these populations healthy, guaranteeing their survival and maintaining biological balance.  They also provide an important service to the ecosystem where they live. In most regions where the harpy eagle inhabits, it was historically known that they fed mainly on arboreal herbivorous vertebrates that feed on the leaves and fruits of forest trees (e.g. two and three-toed sloths, all species of primates, porcupines, macaws, parrots, iguanas, among others). But, nowadays we also know the diet of this majestic eagle includes a great variety of vertebrates with distinctly terrestrial habits (e.g. limpets, agoutis, peccary, deer, multiple species of birds including cranes and vipers).

The conservation of the harpy eagle could also contribute to the conservation of the tropical forests south of the Orinoco. The harpy eagle is a  flagship species. Being charismatic enough, the harpy eagle has been used as a powerful symbol within conservation campaigns in Venezuela for the past 25 year. The success in the conservation of the harpy eagle in Venezuela, and especially  south of the Orinoco, has been based fundamentally on the integration and participation of rural communities that cohabit with the eagle. That integration has been able to reverse the problems faced by this eagle in many locations, as well as by many other terrestrial vertebrates that share different ecosystems as common habitats.

The Venezuelan environmental legal framework contemplates more than 30 years of legal and administrative protection strategies for the conservation of our wildlife and the different biomes within our borders. But, in recent years, concerns have arisen about their effectiveness, especially as a result of the implementation of the Orinoco Mining Arc National Strategic Development Zone (ZDEN-AMO) in the Guayana and Venezuelan Amazon region.  So, we can conclude that a robust legal framework does not necessarily imply a good conservation status.

By the way, a focus on the intrinsic value of the rainforest south of the Orinoco, and its importance as a habitat for the harpy eagle and many other species, should not hide the national and international dimension and significance that the conservation of these forests in particular contemplates. Scientists have presented evidence that rainforests play an important role in mitigating climate change by storing carbon on a large scale. Therefore, the benefits of effective conservation of the forests in the Guayana region, the Orinoco river basin, and the Amazon would spill over far beyond the borders of Venezuela and its south American neighbors.

Finally, the threats to the conservation of the ecosystems  south of the Orinoco should be of major concern to the national and international community. The new frontier in the legal conservation of biodiversity and its habitats transcends the borders of states and national legal systems. The effective legal protection of species and habitats will increasingly require national and international cooperation. The survival of harpy eagles and other species of emblematic vertebrates, which can penetrate international audiences due to their charisma and what they represent for global biodiversity, will depend on the actions that are taken.  That premise and reality must be present in every moment…

References

Álvarez-Cordero, E. 1996. Biology and conservation of the Harpy Eagle in Venezuela and Panama. Ph.D. thesis.Univ. of Florida, Gainesville, FL U.S.A.

Álvarez-Cordero, E. y Ellis, D. (1994). Harpy Eagle (Harpia harpyja) nesting in manipulated forests. Journal of Raptor Research, 28 (1):51.

Banhos A., Hrbek T., Sanaiotti T.M, Farias I.P. (2016). Reduction of Genetic Diversity of the Harpy Eagle in Brazilian Tropical Forests. PLoS ONE 11(2): e0148902. doi: 10.1371/journal.pone.0148902.

Berrotéran, J.L. (2003). Reserva Forestal Imataca: ecología y bases técnicas para el ordenamiento territorial. MARN. 208 pp.

Bevilacqua, M., Cardenas, L., Flores, A. L., Hernández, L., Lares, E., A. Mansutti, A., Miranda, M., Ochoa, J., Rodríguez, M. and y Selig, E. 2002. The state of Venezuela´s forests: A case study of the Guayana Region. World Resources Institute-Global Forest Wash. ACOANA, UNEG, Provita y Fundación Polar. Washington, D. C. (USA) y Caracas (Venezuela). 134 pp.

Bisbal, F. J. (1994): Consumo de fauna silvestre en la Zona de Imataca, Estado Bolívar, Venezuela. Interciencia, 19:1-6.

Blanco-Márquez, P. A. (2007). Harpy Eagle as Detective of the Landscape in the Forest Reserve of Imataca. II Annual Metting of the Eagle Conservation Alliance. Puebla, México.

Blanco-Márquez, P. A. (2009). Vulnerable Eagle Species and Conservation Action in Venezuela. Third Annual conferences of the Eagle Conservation Alliance. Ainsa, Aragon, Spain. 38 pp.

Blanco-Márquez, P. A. y Álvarez, E. (2009).  Estudio y Conservación del águila harpía en Venezuela. I Congreso Venezolano de Ornitología y IV Jornadas de Ornitología y Conservación de Aves de Venezuela. Barquisimeto, Venezuela. 40 pp.

Blanco-Márquez, P. A. & Álvarez Cordero, E. 2009. Investigación y monitoreo del águila arpía (Harpia harpyja) en la Reserva Forestal de Imataca, estado Bolívar. In Una mano a la naturaleza: conservando las especies amenazadas venezolana. Provita y Shell de Venezuela. 220 p.

Huber O. 1995. Geographical and physical features. Pp. 1–61. En: Steyermark, J. A., P. E. Berry y B. K. Holst (Eds.). Flora of the Vene-zuelan Guayana. Vol. 1 Introduction. Missouri Botanical Garden and Timber Press. Portland.

IUCN 2020. The IUCN Red List of Threatened Species. Versión 2020-2. https://www.iucnredlist.org

Lentino, M., M. Salcedo y V. Malavé. 2018. Aves del Escudo Guayanés de Venezuela. Pp. 283-343. En: Lasso, C. A. y J. C. Señaris (Eds.), Volumen VI. Fauna Silvestre del Escudo Guayanés (Colombia-Venezuela). Serie Editorial Fauna Silvestre Neotropical. Instituto de Investigación de Recursos Biológicos Alexander von Humboldt. Bogotá, D. C., Colombia.

Lentino M., D. Esclasans y F. Medina. 2005. Áreas importantes para la conservación de las aves en Venezuela. Pp. 621-730. En: Birdlife International y Conservation International. Áreas importantes para la Conservación de las aves en los Andes tropicales: sitios prioritarios para la conservación de la biodiversidad. BirdLife International. Serie de conservación de Birdlife No. 14. Caracas, Venezuela.

Lew, D., Rojas, H. y Ferrer, A. 2009. Mamíferos del Parque Nacional Canaima. Pp. 151-180, en Biodiversidad del Parque Nacional Canaima: Bases técnicas para la conservación de la Guayana Venezolana (C. Señaris, E. Lew y C. Lasso, eds). Fundación La Salle y The Nature Conservancy, Caracas. 256 pp.

Lozada, J. R. 2012. Deforestación en Venezuela arriesga el desarrollo sustentable. Ecodiseño Sostenibilidad 1, 163–169.

Martínez, G., Álvarez, E., y Álvarez E. (1996). Águila Harpía, Su Ecología y Conservación en la Guayana Venezolana. Revista Natura. 105: 50-56.

O’Bryan, C.J., Allan, J.R., Holden, M., Sanderson, C., Venter, O., Di Marco, M., McDonald-Madden, E., and Watson, J. E. M. 2020. Intense human pressure is widespread across terrestrial vertebrate ranges. Global Ecology and Conservation. 21: 1-7.

Ochoa, J. (1997). Sensibilidades potenciales de una comunidad de mamíferos en un bosque productor de maderas de la Guayana Venezolana. Interciencia, 22(3):112-122.

Ochoa, J. 2000. Efectos de la Extracción de Maderas sobre la Diversidad Mamíferos Pequeños en Bosques de Tierras Bajas de la Guayana Venezolana. Biotropica, 32: 146-164.

Oliveira-Miranda, M.A., O. Huber, J.P. Rodríguez, F. Rojas-Suárez, R. De Oliveira-Miranda & S. Zambrano-Martínez (2010). Bosques siempreverdes per se. Pp: 124-129. En: J.P. Rodríguez, F. Rojas-Suárez & D. Giraldo Hernández (eds.). Libro Rojo de los Ecosistemas Terrestres de Venezuela. Provita, Shell Venezuela, Lenovo (Venezuela). Caracas: Venezuela.

REPÚBLICA DE VENEZUELA. (1996a). Lista de animales vedados para la caza. Decreto 1485, Gaceta Oficial de la República de Venezuela Nº 36059, Caracas.

REPÚBLICA DE VENEZUELA. (1996b). Lista de especies en peligro de extinción en Venezuela. Decreto 1486, Gaceta Oficial de la República de Venezuela N° 36062, Caracas.

Rivero-Blanco, C. 2017. Arco Minero del Orinoco: Otra visión. Gente, Comunicación y Ambiente, Serie Documentos Técnicos de Vitalis. Proyecto Observatorio Ambiental de Venezuela, Caracas, Venezuela. 26 pp.

Rodríguez, J.P. & F. Rojas-Suárez (eds.) 2008. Libro Rojo de la Fauna Venezolana. Tercera Edición. Provita & Shell Venezuela, Caracas, Venezuela. 322 pp.

Rojas-Runjaic, F. J. M. y J. C. Señaris. 2018. Reptiles del Escudo Guayanés de Venezuela. Pp. 179-229. En: Lasso, C. A. y J. C. Señaris (Eds.), Volumen VI. Fauna Silvestre del Escudo Guayanés (Colombia-Venezuela). Serie Editorial Fauna Silvestre Neotropical. Instituto de Investigación de Recursos Biológicos Alexander von Humboldt. Bogotá, D. C., Colombia.

Sánchez, J., & Lew, D. 2012. Lista actualizada y comentada de los mamíferos de Venezuela. Memoria de la Fundación La Salle de Ciencias Naturales, 173-174:173-238.

Señaris, J. C. y F. J. M. Rojas-Runjaic. 2018. Anfibios del Escudo Guayanés de Venezuela. Pp. 101-149. En: Lasso, C. A. y J. C. Señaris (Eds.), Volumen VI. Fauna Silvestre del Escudo Guayanés (Colombia-Venezuela). Serie Editorial Fauna Silvestre Neotropical. Instituto de Investigación de Recursos Biológicos Alexander von Humboldt. Bogotá, D. C., Colombia.

Alexander Blanco
Veterinarian. Master in Conservation Biology and Wildlife Management. President of Fundación Esfera.
Director of the Harpy Eagle Conservation Program in Venezuela


0 Comments

Deja una respuesta

Tu dirección de correo electrónico no será publicada. Los campos obligatorios están marcados con *

es_ESSpanish