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Oil palm tree crops reduced the Colombian eastern plains foothills bird population by 90%

The green, leafy and thriving plants and bushes visited by more than a hundred species of multi-colored birds, including five species which migrate from the United States, Canada, Argentina, and Chile– have been progressively displaced. Now, there are endless rows of African oil palms, more than 30 meters high, that rats, mice, snakes and raptors call home.

Maybe the insects are the sole survivors of this transformation that has occurred in the country with the most number of bird species in the world: Colombia.

In face of this situation, Biologist Diana Tamaris and Universidad Nacional de Colombia (UNal) Sciences-Biology Ph.D., regrets this change and says: “We are terminating our patrimony”.  

Tamaris is the author of the most recent and complete research project over the impact of this oil palm monoculture on the biodiversity and bird population of the Colombian tropical forests.

One of the most shocking facts about the project is that 90% of the bird species that thrived in the Colombian eastern plains foothills are not there anymore. While for other crops such as coffee and rice, the number of species is 140 and 150 respectively, oil palm species have been reduced to only 44.

Birds are essential for the ecosystems as they are a natural biological control avoiding the proliferation of harmful insects for the crops of the region.

“Inclusively, loss of the plant coverage produces an unstable ground liable to erosion, which produces lands slides which directly impact the roadways and population centers, as has already occurred in many places in Colombia,” she added.

Besides filling a void of scientific literature in Colombia on the topic, Tamaris’s research project ratifies the disrepair and impoverishment of the bird populations in countries such as Malaysia and Indonesia, where oil palms occupy an important part of their territory.

This confirms the idea that independently where they are planted, oil palm trees produce “loss and reduction of the biodiversity”, therefore this effect may be considered “a behavioral pattern.”

However, her interest as a Biologist is not for oil palm crops to be terminated but to crop with less possible negative impact over the bird populations. Therefore, she offers a series of suggestions to crop oil palms in a sustainable manner.

Crops all around Colombia

Colombia is the first producer of oil palm in Latin America and fourth in the world, just after Indonesia, Malaysia, and Thailand.

The crop is present in all four cardinal points of the country, in 124 of the 1,122 Colombian municipalities and 20 of its 32 provinces.

Tamaris also measured the alteration of the environment as a consequence of oil palm cultivation, along with the support of UNal Sciences Ph.D. Hugo Fernando López.

The researchers walked into crops of the municipalities of San Martín de los Llanos and Acacías (Province of Meta), located in the eastern part of the country where there is the greatest number of oil palm crops (141,068 hectares recorded between 2015 and 2016).

The purpose was to observe and identify the species of birds according to the three different kinds of oil palm trees. They sampled each tree height:  small (less than four meters), medium (between 4 and 18 meters) and large (more than 18 meters).

The field work consisted of hiking within the crops for 2.5 kilometers, after which they stopped to observe and wrote down the species that passed through. After, they continued with the exploration. This is the census method usually applied in this type of research projects.

The other technique they used was mist nets, which consisted of using a polyester mesh suspended between two poles at approximately 12 meters high. As birds cannot see them, researchers capture the birds, measure their form and structure, take photos and later release them.

With this information, the researchers counted the birds that arrived to the crops and compared these results with existent inventories and information of the species of the Colombian Orinoquia region.

Bird wealth reduction

To the question: How do oil palm crops affect bird populations? The result was overwhelming: they only discovered 44 species comprised of 468 individuals from 23 families of birds.

Comparing this information was the starting point that allowed the researchers to verify the low number of birds associated with African oil palm crops.

According to Tamaris, most of the 44 species are of “little preservation value, greatly distributed, and without threat or migratory quality.” They are very resilient residents, tolerant to the alternations of the environment, such as the Venezuelan troupial, the great-tailed grackle, the tiwa and other raptor birds.

Only 10.6% of the species remain in the Colombian eastern plains foothills

The researchers also analyzed what percentage represented the birds remained and compared them to birds of the region, province, and eastern hills foothills. For this they used the Orinoquia Bird Report published by professors Orlando Rangel and Orlando Acevedo, according to which there are 761 species of birds; they discovered that:

  • Of the 761 species recorded in the region, 44 of them in the crops represent 5.78%.
  • Of the 683 recorded in the Province of Meta, 44 correspond to 6.4 % of the province.
  • Of the 414 species identified in the foothills, 44 are the 10.6%.

Does this mean that 90% of the birds of the foothills disappeared? The researcher prefers to speak of “possible local losses or that they are taking refuge in other locations.” When the birds lose the possibilities that the forest provided them they look for other places. An example is the rice crops which were predominant before in the region where the research project took place.

These crops work as wetlands where birds gather as it provides a safe harbor to their nests, feeding, rest and reproduction. But as they have been displaced and native formations have been lost, species such as the following are being seriously affected:

  • The buff-necked ibis (Theristicus caudatus)
  • The double-striped thick-knee (Burhinus bistriatus)
  • The yellowish pipit (Anthus lutescens)
  • The scarlet ibis (Eudocimus ruber)
  • The Maguari stork (Ciconia maguari)
  • Red-bellied macaw (Orthopsittaca manilata)
  • Orange-winged amazon (Amazona amazonica)
  • White-throated toucan (Ramphastos tucanus)
  • And the black-throated antbird (Myrmeciza atrothorax).

Besides, migratory birds that do not have these places to rest, feed and continue on their route. “It is as if the species wealth thwarted, as that 10% of the birds remain for 40 years or more… the wealth does not change,” said López.

Furthermore, he claims that there is another loss associated with the number of species and that is the role of the forest. The species that feed on fruits and pollinate flowers are displaced as the forest is devastated; therefore there are new interactions between species, which compared to forests and savannahs are much more impoverished and deteriorated.

Precisely, the study substantiated that the conditions of the forests are much more favorable for bird species than the palm tree conditions. While 84% of the species remained in the forest, only 37.5% remained in the oil palm crops.

This impoverished trend and loss of biodiversity may be applied to other regions with the same types of crops. “Why do we dare to claim this?” says Tamaris. Because in her research project they verified that the trend discovered in oil palm impact studies in other countries, such as Malaysia and Indonesia, is the same: “Loss and reduction of biodiversity”. Therefore, she considers this to be “a pattern”, as they have similar impacts in different parts of the world

Soil degradation

Using lands to crop oil palm implies stripping the land of its plant coverage. According to Tamaris, “There are hundreds of hectares that are stripped without quantifying biodiversity loss in face of this rapid cropping process.”

For instance, in the region analyzed that the land layer corresponds to gallery forests, in other words, the forest linked to water circuits and with abundant mountain bushes, remnants of native vegetation and moriche palm groves, characteristic eastern plain formations.

Therefore, the land is prepared for only oil palms, which at the beginning are small but after they begin a more than 30-year life cycle, an overly extensive time period for birds.

Economic interest vs. environmental interest

The main incentive to increase oil palm crops is its productivity, as after two or three years after planting and transplanting, “the crop begins to produce, produce and produce,“ added Tamaris.

Palms may be exploited for up to 30 years, but not because the crop ends, but because the harvesting becomes difficult due to the height of the tree, which is then replaced.

Added to the prior, the government provides economic incentives, such as easy access to credit lines for small and medium-sized farmers to extend their crops. This is very attractive to producers as oil palm products and byproducts are used in other industries such as:

  • Foods
  • Cosmetics
  • Pharmaceutics
  • & Tobacco companies

As well as margarine, liquid oil, ice cream, cream, animal dry food, soap and biodiesel products.

A change in the food chain

The effect of this intensive use has gradually changed the native food chain. Oil palm cropping implies cutting leaves and leaving them in piles, besides of the fallen fruit. This new dynamic is perfect for rodent food, hunting, and habitat, as they find everything they need in this environment.

Then come the snakes that feed on the rodents and decomposed meat, as people kill both snakes and rodents and leave them to rot for carrion birds to complete the process. “Therefore there are new relationships which are necessary that we begin to comprehend,” said the researcher.

Tamaris is well aware that her research project is not a “hindrance to the development train,” as she verifies this every time she visits these crops. Despite recognizing the good intentions of many oil palm farmers to minimize the impact to the environment, she has also seen farmer owners that even remove river vegetation in order to afford more space to crop. This is a very discouraging scene.

Research project suggestions

The Universidad Nacional de Colombia study makes the following suggestions to make oil palm crops sustainable and reduce the impact on bird populations:

  • Mixed crops. Crop palms along with different crops to foster heterogeneity and increase the association of diversity.
  • Vegetation circuits. Oil palm land plots need to have vegetation borders to warrant the permanence of native biodiversity and favor mobility for species of all kinds, not only birds.
  • Smaller land plots. Crop in smaller land plots and different sizes to favor biodiversity, as discovered in other research projects.

For the research project group, these practices may help protect the biodiversity and produce a friendlier environment both for birds as for other native species of the region.

How the African palm tree arrived in Colombia

  • Its origin is New Guinea (Oceania).
  • It was brought to the Province of Valle del Cauca in 1932 when it was planted for ornamental reasons.
  • The first specimens appeared in 1945 in the Province of Magdalena.
  • The United Fruit Company was the first banana company which planted African palm trees for commercial purposes.
  • Since then, its commercial cropping began and has expanded throughout Colombia.
  • Up to 2016, there were 58 oil palm growing centers in Colombia.

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