Memorias de la RSEHN (segunda época)

La superpoblación del ser humano es una de las causas que más está infl uyendo en el deterioro que sufre el planeta Tierra en la actualidad. La adaptabilidad del ser humano y su efi ciencia para modifi car el medio está provocando que para satisfacer sus necesidades requiramos de, al menos, cinco o seis planetas.

Las acciones del hombre sobre el planeta tienen tanto carácter puntual como global. Todas estas actuaciones están provocando una reducción de la biodiversidad a un ritmo no conocido en épocas anteriores.

En los últimos años se ha incrementado en más de un 10% el número de especies amenazadas. Desde 1800 han desaparecido 103 especies, lo que indica una tasa de extinción 50 veces superior al ritmo natural. Las estimaciones más pesimistas hablan de una pérdida de hasta 30.000 especies al año, lo que implica más de 80 especies diarias.

Para solucionar el problema se han planteado soluciones globales mediante la Estrategia Mundial para la Conservación de la Naturaleza, el Convenio sobre la Diversidad Biológica o el Plan de Acción para detener la pérdida de biodiversidad para 2010 y en adelante. Somos causantes de la llamada “sexta extinción” pero en nuestra mano está evitarla.

Human overpopulation is undoubtedly one of the reasons that most infl uence in the enormous worsening that is suffering the Earth today. Human adaptability and their effi ciency to modify the environment is making that we require of at least 6 or seven planets to satisfy the current human needs.

Disturbances of man on the planet have both an infrequent nature, -on specifi c habitats and species-, as a global nature, -changing weather conditions, altering water composition and homogenizing the Earth-. All these actions are causing a decline in biodiversity on the planet at an unknown rate in earlier times.

However, the human being is not only capable of destroying the environment but also has the ability to restore the damage caused. Our only doubt is if we are on time to solve it.

According to IUCN (2003), the number of species with documented extinction since the sixteenth century has been of more than 800, of which 330 are vertebrates (78 mammals, 132 birds, 22 reptiles, 7 amphibians and 91 fi sh), 381 invertebrates (303 molluscs, 70 insects and 8 crustaceans) and 99 plants (4 monocotyledons and 95 dicotyledons). The number of threatened species has increased in more than 10% in recent years. Since 1800, 103 species have disappeared indicating an extinction rate 50 times the natural rate. The most pessimistic estimates speak up to 30,000 species that disappear each year, involving more than 80 species per day.

The number of seriously threatened vertebrates has increased signifi cantly since 1996 (22% of mammals, 13.6% of birds, 23% of amphibians, 25% of reptiles and 30% of fi sh). But worst of all is that defi nitely many species have already been lost and, at this rate, many more will be lose even before being discovered.

Plants are also in danger, there are a total of 5.611 threatened plant species -many of them arboreal- although only 4% of higher plants have been evaluated. Global solutions have arisen to solve the problem through the Global Strategy for the Conservation of Nature, the Convention on Biological Diversity and the Action Plan to halt the loss of biodiversity. We are responsible of the “sixth extinction” but in our power to avoid it

Neither society nor government can be indifferent to this evidence considering that they take actions to reduce biodiversity loss, so that are achieved some conservation successes. Nature is the largest company in the world, that works to the benefi t of 100% of humanity - and does it for free -. Governments should invest as much effort, if not more, to save nature and not to save the economic and fi nancial sectors. For example, in North America and Eurasia the number of threatened species are maintained and reduced by 43% respectively, while in South America, Africa and Indo-Pacifi c, endangered species have increased by 55, 18 and 6% respectively.