This is how it was explained by the emeritus researcher at the Center for Ecology of the Venezuelan Institute for Scientific Research (IVIC), Rafael Herrera, who has recently served as visiting professor of Geoecology at the University of Vienna, Austria.
“Probably this wide repository of species has served and will serve to adapt to environmental variations. Faced with climate change, we could hope that a completely different group of species that today dominate the carbon cycle will emerge ”, he communicated.
Recently, a team of 97 scientists from 64 international institutions working in nine Amazonian countries announced that half of the carbon in the Amazon was concentrated in just over 1% of the 16,000 known species in the region.
With this finding, published in the journal Nature Communications last April and of which Herrera is a co-author, it was natural to wonder if the remaining of these species corresponded to expendable for ecological balance.
“From now on that we know that at least for several parameters such as the number of people, productivity and the carbon cycle, a small proportion takes a preponderant role, we consider that in this apparently wide diversity of support, lies the ability to react to environmental changes, ”he explained.
The Amazon, together with the Orinoco basin, still represents the largest tropical forest in the world, occupying 6.2 million square kilometers.
It is even responsible for 14% of the carbon fixed by photosynthesis in the terrestrial biosphere and 17% of the existing carbon in terrestrial vegetation, as indicated by the international study led by researcher from the University of Leeds, Sophie Fauset.
Its biodiversity, calculated at 16,000 species of trees, is still the most extensive to date, however behind this explosion of life is the phenomenon of hyperdominance, described in 2013 by another group of experts.
Hyperdominance refers to the concentration of biological diversity in very few species. According to the work published 2 years ago in the journal Science, one hundred and fifty% of all the trunks analyzed corresponded to only 227 species.
One wondered then if this hyperdominance was even reflected in vital processes such as the carbon cycle and productivity. "Our article answered that question, although surely, even of these variables, there will be other processes in which hyperdominance has some relevance," said Herrera.
Reproduction and recruitment, transpiration, contribution of litter to the soil, behavior of animal species associated with tree species, among other parameters, appear on the list of candidates to study in the future with respect to hyperdominance.
As an example, Herrera cited the case of the palm trees of the Arecaceae family, one of whose species Iriartea deltoidea is part of the list of the 20 most dominant species with influence regarding the carbon cycle and productivity. "It is aptly named that they have a very high hydraulic efficiency due to the anatomy of the vascular system and its magnification mode," he announced.
The data used for the research consisted of 530 individual plots located at sites below 500 meters above sea level in mature forests.
These plots contained 206,135 trees of 3,458 species, for a total of 114,696 megagrams of biomass. Biomass is understood as the total dry weight of the plant material of the trees. The higher the biomass density, the higher the carbon storage.
The Ivic researcher, Rafael Herrera, commented that of the nine Amazonian States where the measurements were carried out, Venezuela points for 2 fundamental reasons: many of the observation sites are in the national Amazon and in the basin linked to the Orinoco River, and our country was the forerunner of systematic studies of tropical humid forests.
Herrera alluded to the network of permanent plots of the various types of Venezuelan forests, created in 1956 by the professor at the University of Los Andes (ULA) in Mérida, Jean-Pierre Veillon. "These plots still exist and are still being studied by researchers at the ULA," he reported.
As well as these contributions, in the 1970s the Ivic coordinated a multidisciplinary project in the Amazon, specifically in the vicinity of San Carlos de Río Negro, with the collaboration of scientists from Germany and the United States and the endorsement of the United Nations Educational, Scientific and Cultural Organization (Unesco), within the Man and the Biosphere Program (MAB).
“The plots established in 1975 are still measured regularly, so that my participation in this work can be said to have started 40 years ago and I consider myself fortunate to continue studying the same trees, some thousands of them, in a coordinated way and with methodologies approved by the Amazon Forest Inventory Network (Rainfor), Herrera added.
According to the Ivic researcher, in recent years it has become common and necessary to articulate forces to solve complex problems that merit the assistance of many scientific disciplines and observations in different places. Carbon emissions are one of them.
Reports from the Food and Agriculture Organization of the United Nations (FAO) suggest that carbon emissions from the degradation of the world's forests have increased between 1990 and 2015. Degradation is the reduction in the density of the tree biomass due to human or natural causes. The greater the degradation, the fewer the number of trees, which in turn means less absorption of carbon dioxide, the main culprit in temperature increases.
Ibero-American Agency for the Diffusion of Science and Technology