Never before has there been so many threatened plant species. Their total disappearance not only means an irreparable loss for the existent diversity, but also affects the equilibrium of the entire ecosystem. Let’s just think that for each species of plant, estimates say that between 20 and 40 species of animal depend on it for their survival, reason for which each extinct plant can make numerous animals disappear.
In all endangered ecosystems, both natural threats and the ones that have to do with Man alternate as the main causes for the extinction of species. Unfortunately, in some of the major biodiversity reserves, like South America or southeast Asia, the irreparable loss of many plants is suffered everyday, some of which there isn’t even much information on.
Human threats
Once again, habitat destruction is pointed out as the direct cause of the extinction or vulnerability of many plant species. This way, the expansion of urban zones, land used for excessive grazing, the deforestation of vast areas, and even intentional forest fires affect the plants that naturally inhabit said places, brining them to their extinction.
Illegal commerce is also one of the serious problems that affect plant species. Every year, an estimated 7 million cacti and 9 million orchids are collected from their natural habitats in order to satisfy the tastes of collectors that look for rare species.
Unfortunately, only 10% of the specimens captured survive their handling, enclosing, transportation and hygienic conditions, so it’s not even possible for them to stay alive.
A clear example of this concerning situation is what is going on in the Chihuahua desert, in Mexico. This zone is renowned for its huge plant biodiversity, which is reflected in the large amount of existent cacti: estimates say nearly 1,500 of the species known to this day live there, which are threatened by extinction due to the constant pursuit of merchants that ignore their importance to nature and trade them as merchandise.
One of the phenomena that directly affects the survival of plant organisms is the one related to the loss of plant genetic variability. Due to the use and popularity of certain high performance crops, a variety of different plant species are gradually decreasing at an alarming rate. According to studies conducted by the FAO (The Food and Agriculture Organization of the United Nations), estimates say that, in the last 100 years, nearly 75% of agricultural genetic diversity has been lost. A concerning figure that doesn’t look like stopping; even the introduction of GMO’s (genetically modified organisms) is affecting the survival of unique varieties of plants, benefiting the ones that are better and more profitable commercially.
The introduction of foreign plants and animals has also caused the frequent elimination of certain species of native flora. Their development instead of that of the natural plant inhabitants is a direct threat and it causes serious ecological unbalances. For example, on the Hawaiian Islands, the introduction of herbivores, like pigs, cows and goats, which forage and graze everyday, has caused the total extinction of nearly 10% of the endemic plants and has endangered nearly 50% of the same.
Natural threats
One of the most direct natural causes that threatens plants is the appearance of pests. Be it diseases or insects that spread at an alarming rate, the latter can destroy important sections of crops or native plants in only minutes. For example, a swarm of locusts, one of the pests most feared by farmers, can span around one thousand square kilometers and be made up of 50 billion locusts, who thrash a great amount of plants and cause important economic losses.
Forest fires (in which Man is not involved and are caused, for example, by a strike of lightning) are one of the factors that can affect the disappearance of some plant species. Generally, they happen during periods of drought, moment in which the conditions are set to not only destroy the existent vegetation, but also destroy the substrate it lived in for many years.
Another factor that can alter the natural equilibrium of an ecosystem and directly affect the survival of any plant organism is the presence of a few meteorological phenomena, like floods, tornados, hurricanes and earthquakes. They can move the species from their natural habitat and make many of the existent plant organisms vulnerable.
An example of this situation is what took place during 1999 to 2002 with the Anchusa crispa bush, plant that is only found in the coastal dunes of the islands of Corsica and Sardinia, where it grows in a limited space of no more than 10 square kilometers. According to the IUCN (World Conservation Union), this species is Critically Endangered due to the fragmentation and decline of its populations, especially because during the aforementioned years, strong storms moved an enormous amount of sand onto the Anchura crispa specimens, causing death and an important drop-off in their population.