Maltese biodiversity under threat
by Jeffrey and Arnold Sciberras
With an area of just 315 km2, Malta is one of the smallest countries in Europe, even in the world. However, geographically speaking, the Maltese Islands are the second largest archipelago off the North African plate, after the Canary Islands, while the island of Malta on its own, as the 36th largest island in the Mediterranean, is the second largest island off North Africa in the Mediterranean Sea, after Djerba Island.
Despite Malta being a densely populated country, with 35 per cent of its area totally built up, 60 per cent agricultural and the remaining five per cent natural or semi-natural, the total number of plant species found in the Maltese Islands is equivalent to 50 per cent of those found in Germany. Many more species of animals, even just terrestrial invertebrates, are found in the islands and marine wildlife is equally rich.
Despite such biodiversity, the local human population – since man colonised the islands around 7,000 years ago – has put a tremendous pressure on land and on the few natural resources it offers.
The destruction of local natural ecosystems has led to the extinction of many native species, and others are now on the verge of disappearing from our islands. Many of these now extinct native species have been replaced by introduced species, completely altering local habitats and adversely affecting the ability of native species to colonise new habitats or retain existing ones. The result is a complete change in the scenery and ecology of earlier years.
It has now become very difficult for naturalists to distinguish between native and alien species, thus making it more debatable to determine which species to protect. Only past and present literature can reveal what is what. The overall point here is to realise what species are on – or will be on – the endangered list, in order for protection measures to apply.
It is necessary to define what is meant by “endangered species”. As the word endangered implies, these species are identified as being at high risk of becoming extinct in the near future. Endangered species are often listed on an international basis, i.e. they are in danger in a global sense. Typical examples of this are pandas, lions, elephants, gorillas, tigers, etc., where – as is the case with some local endemic species – if they disappear from their native home they will become extinct forever. There is a long list of endemic species that are under threat. The other category of endangered species includes those that are in danger at a local level and which, even if they become extinct in one place, may still exist elsewhere and not necessarily be in danger in that area. One famous example of a locally extinct species is the jackdaw, a type of crow, which is common elsewhere in Europe. Sub-endemics, semi-indigenous and indigenous species fall under this category and the Local Red Data Book includes such a list.
There are two things that will result in a species being listed as endangered: their rarity and their fate. The weasel, which was the popular figure on the Maltese liri one cent coin, is now a very rare species locally, found only in the western areas on the main island, Malta. Despite the abundance of its prey, such as rats and rabbits, its rarity indicates that, locally, the weasel seems incapable of repopulating to any significant extent, and with a loss of habitat, coupled with persecution, it is now an endangered species. On the other hand, the hedgehog is not currently listed, but it may be in the near future, due to pesticides, reckless driving and habitat destruction. The honey bee, practically a cosmopolitan these days and apparently resilient to mankind’s destruction, is in fact in danger of becoming extinct in an instant, due to the recently understood colony collapse disorder, where entire colonies abruptly disappear. Colony collapse is economically significant because many agricultural crops worldwide are pollinated by bees, and agriculture is the most essential of human needs. If the honey bee becomes extinct globally, life for humans will never be the same again.
Well known local species of animals that are endangered are the Maltese wall lizard, especially on the islets, which are all endemic populations, the painted frog, which is sub-endemic, and the Maltese freshwater crab, an endemic sub-species. Well known endangered species of plants include the Maltese everlasting, which is endemic to western cliffs of Gozo, and the Maltese cliff-orache which, although also found on the island of Malta, is more endemic on a genus level, that is both genus and species are endemic to the Maltese Islands, and it is the only local plant to have that status. This status also applied to the Maltese rock centaury (the national plant of Malta), but in 2000, its genus became sub-endemic to the Canary Islands. Typically endangered indigenous and sub-endemic species of plants and trees are the wild rosemary, hoary and narrow-leaved rock roses, the sandarac (the national tree of Malta), the Maltese toadflax, poplar and wild myrtle.
The endangered species list is long, which is worrying. With so many species under threat, such as the difficult to spot and elusive sand cricket and sand ant-lion, most are considered insignificant and thus their conservation may not seem important. However, for naturalists, they are a goldmine. Their isolation has become the key to understanding evolution, and genetic studies have proved that distinct populations contribute to endemism, which is of great importance to our local natural heritage.
It is due to genetic studies that we understand that species can be also threatened. The introduction of alien species such as ornamentals or exotic pets eradicate local species not only through competition for space, but also through genetic erosion or pollution. This terminology may seem bizarre, but the fact is that it is the truth and it is happening all over the world. The introduction of already-existing species will not help increase local populations, but will most likely damage them. Different populations of the same species will, over time, become distinct and thus become separate populations, due to geographic isolation and the prevention of cross-breeding. When that natural barrier is destroyed, such as with the introduction of foreign varieties, evolution is back to square one. Locally, the rosemary, Maltese stocks and olive-leaved germander are in danger of being pollinated by foreign cultivated varieties, with the result that their offspring will no longer be genetically pure and the population will no longer remain distinct. In plants, it may not have been easy to observe, but it is there. In animals, it is more visible and evident. Take the rock dove as a classic example. True rock doves are naturally found on the islands’ cliffs, mainly for breeding, and are often shy and solitary. The rock dove has been domesticated for more than a thousand years and as a result several breeds have emerged. The outdoor breeds are the likely cause of the current worldwide feral populations of town pigeons. Domestic pigeons that escaped and survived independently from humans, bred with the wild rock doves, resulting in the multitude of coloured town pigeons we see today.
Pollution is one of the major causes for climate change and species extinction. The rate of climate change is one big factor, but other forms of pollution are at work. The best known of these are water and air pollution. But who ever thinks about light and noise pollution? Hardly anyone, but they exist. The most visible cause of light pollution, from the naturalists’ point of view, is the dismantling of the nocturnal ecology. Looking at light bulbs outside at night, one can see insects constantly bumping into the bulb. For some strange reason they are endlessly attracted to it. These insects are mistaking the artificial light source as stars or the moon, which naturally guide them to find nocturnal flowers and mates at night. The artificial light source is so near to them that they can go straight for it. While exhausting themselves on the bulb, they lose precious time for feeding and mating, and probably end up dead by morning. This interference has led to a reduction in the number of many nocturnal species, including bats, which feed on such insects. Noise pollution has less visible causes, but mating calls, migration and breeding patterns are all changing as a result of the presence of noise.
Alternative human activities, such as hunting and off-roading, also contribute to species annihilation. Both migratory and residential species of birds have been greatly affected by hunting, in one way or another and, by its very nature, off-roading can destroy natural vegetation. In both cases, there must be better law enforcement and actual events must be controlled by local authorities at all times.
After reading this sort of article, people may wonder what, as individuals, they can do in order to save these species. One person alone may not make a difference, but together they can. Naturalists are constantly challenged to study and observe the species that surround us, but it is also their duty to show others what nature offers so that their research and conservation efforts will not be in vain. Educating the young is one of the pillars of conservation and reducing consumption needs is another, along with reducing waste and global emissions and preserving the land, the sea and their habitats. Recycling, joining non-government environmental organisations and getting involved will also help. Ultimately, it will assist endangered species to become less threatened, and will also help people to live in harmony with them. What we do to the earth, it will do to us.
This article is a summary of the lecture entitled The endangered wildlife
of the Maltese Islands that
was presented by the authors to
HSBC Climate Champions Group