By Rebecca Bloomfield
Biodiversity – or biological diversity – is the variety of life found on our planet. While that may sound simple, it is in fact one of Earth’s most complex features. Biodiversity is a key indicator of an ecosystem’s health; high biodiversity means a wide variety of species, which will cope better with threats than a more limited number. This is particularly important in today’s climate, given the increasing factors that are threatening our plants and animals. Biodiversity ensures natural sustainability and can be considered a library of how to survive. Years and years of evolution have taken place within species as they learn to cope with disasters such as disease and changing environmental conditions. The benefits we stand to gain from this knowledge are priceless, yet we are losing species and the important properties they provide at an increasingly worrying pace. An estimated 1.7 million species of animal, plant and fungi have been recorded so far, but estimates suggest that there could be somewhere between 8 million to 100 million yet to be discovered.
Biodiversity can be measured using many different methods. Species diversity, the number of different species found in an area, for example, shows variation and means that there are many roles being carried out – from butterflies and bats pollinating the flowers to the predators keeping rodent population numbers in check. Biodiversity is also measured through genetic diversity; the genetic differences between plants or animals of the same species, which improves the chances of surviving disease outbreaks without risking extinction.
Another measure of biodiversity is endemism. Endemic species are plants or animals that are only found in a certain area or country. In Malawi, one such species that has been identified and is heavily monitored is the Mulanje Cedar, an endemic Malawian species which occurs naturally only on Mulanje Mountain. Due to illegal logging, the species is critically endangered. The country also boasts Lake Malawi, one of the most biodiverse lakes in the world where around 15 percent of the world’s freshwater species are found. Lake Malawi is home to over 800 species of fish, 90 percent of which are endemic. Additionally, it is estimated that approximately 47 species of the 172 species of molluscs, 12 species of reptiles and about seven species of amphibians are endemic to Malawi. These statistics show that Malawi has unique biodiversity, which is important to maintain not only for the country but for global biodiversity levels as a whole.
Why are we losing biodiversity?
The world is undergoing the greatest mass extinction since the dinosaurs were wiped out 65 million year ago. In the last 100 years, around 50 percent of our planet’s species have gone extinct. Biodiversity is under threat from many factors and is decreasing so rapidly that we may well be losing species before we’ve even discovered them. Despite the fact that humans make up a tiny 0.01% of all life on the planet, we have destroyed 83% of wild animals and half of all plants. A major issue is habitat loss; almost half of the world’s surface is agricultural land used to grow crops or raise livestock. This land is notoriously low in biodiversity due to only a select few species being used on farms. A field of corn is drastically lower in species than a similarly sized area of woodland. Our forests are also suffering, as trees are being cleared to make way for fields and farms, commercial harvesting, or to be used for firewood. Malawi relies heavily on wood for wellbeing and livelihoods and, despite its small size, has one of the highest deforestation rates in the world – and the highest in the Southern African Development Community (SADC). This highlights the urgency for sustainable action plans to be put into place. Deforestation also has an impact on the animals that once depended on the forests. They are left to migrate to untouched areas of wilderness or to try and adapt to living in farmland – a choice which can result in them being killed.
Introduced species that are not native to the area, and have been brought there by people or as a result of globalisation and transport across the world, can also cause an issue. Approximately 400,000 introduced species out-compete native species for food and territory, resulting in the populations of native species to decline. In Malawi, the Nile tilapia was introduced to Lake Malawi for fishing purposes, however it has become a competitor and predator of native species and has been the cause of a loss in fish biodiversity globally. Water hyacinth, another introduced species, has negatively affected Malawi’s aquatic ecosystems by reducing water oxygen and outcompeting native plants.
Additionally, over-exploitation is also reducing biodiversity. Hunting and logging are happening at a faster rate than reproduction, meaning that species cannot keep up with replenishing their populations. It is thought that more than 300 mammal species, including 188 species of primates and all 8 species of pangolins, are being poached into extinction. Rapid population growth in Malawi has increased demand for natural resources, but a lack of sustainability has resulted in cases of overharvesting.
Other factors affecting biodiversity levels in Malawi (and indeed worldwide) include climate change and pollution. Shifts in rainfall patterns have affected the planting period, making it harder for indigenous crops to survive, and pollution run-off into rivers can result in high levels of agricultural chemicals having negative impacts on ecosystems.
Why should we be striving for biodiversity?
We rely heavily on biodiversity for a great many things and these benefits that we gain from the environment are called ecosystem services. These services are many and varied: forests provide a carbon sink and help to store the carbon dioxide in the atmosphere; coastal ecosystems and barrier reefs provide storm protection and natural harbours; wetland ecosystems provide flood control and help reduce erosion. In Malawi, ecosystem services and biodiversity play a key role in attracting tourists. In 2010, fisheries, forestry and wildlife sectors contributed 12.8% towards the country’s GDP. Ecosystem services also provide the country with food. It is estimated that more than 500,000 people who live near Malawi’s freshwater habitats depend on fish as a source of food and livelihood.
Maintaining biodiversity in these areas will ensure employment and food security, as high diversity improves the health of the ecosystem and increases productivity. Furthermore, having a large variety of species of plants increases the number that we can use for food and industrial materials. This is particularly important for the medicine industry, with more than 60% of the world’s human population relying almost entirely on plant medicine for primary health care. If biodiversity were to decrease, the plants required for this medicine may be in short supply. Malawi has over 131 plant species that are used as medicinal plants, including the Baobab fruit which has high anti-oxidant levels. Biodiversity additionally can provide models for structures that we use, such as Velcro, inspired by the hook-like properties of the burdock plant, and Olympic swimsuits, inspired by the water dynamics of shark skin.
Ecosystem services are undeniably priceless, as we would be unable to survive without them, but put their value into a figure and the services are estimated to be worth trillions of dollars – around double the world’s market value of goods and services produced. In fact, biodiversity loss in Europe costs the entire continent £400m every year, with technology having to replace the lost species that were providing ecosystem services. The cost of biodiversity loss across Africa is likely to be even greater.
How can you help improve biodiversity?
Helping the environment may often seem like a difficult task for one person. While the creation of wildlife reserves and the use of sustainable farming methods that encourage diversity of crops and traditional agriculture techniques are vital, there are ways to help that can be done at a personal level. Helping pollinators such as bees and butterflies to thrive in your garden by planting insect-friendly flowers will boost the number of plants that are being pollinated. Similarly, encouraging birds into your garden will aid seed dispersal and prompt plant populations to spread.
Reducing the use of chemical pesticides and fertiliser will prevent harm to other animals that aren’t being targeted by the chemicals. Instead, consider natural fertiliser and organic pest control. Encourage the animals that eat the pests into your garden and let them deal with infestations. You can also cut down on meat consumption, avoid products containing palm oil, and have a go at growing your own food to reduce the demand for forests to be cleared for agricultural land. Speaking up for nature, endorsing biodiversity, and supporting charities that work towards conserving the natural world will also aid in spreading the message that biodiversity is important.
The future of the millions of species on our planet is uncertain. What is not uncertain is that humans are causing this devastating biodiversity loss – and the situation is not going to improve without our intervention.