Why Mountains Are Biodiversity Hotspots
Wed, April 21, 2021

Why Mountains Are Biodiversity Hotspots

Biodiversity is what makes life possible on Earth. Humans have been depending on the natural richness of our planet for the food, water, energy, and raw materials it provides / Photo by: USAID Biodiversity & Forestry via Flickr

 

Biodiversity is what makes life possible on Earth. Humans have been depending on the natural richness of our planet for the food, water, energy, and raw materials it provides. However, the rate of biodiversity loss has not been reduced over the past few decades. The four principal pressures on biodiversity have been persistent – and have even intensified. This includes habitat loss and degradation, climate change, excessive nutrient load and other forms of pollution, and the overexploitation and unsustainable use of natural resources. 

Earlier this year, a new landmark report from the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) showed that nature is declining across the world at rates unprecedented in human history. According to the UN report, around one million animal and plant species are now threatened with extinction. About 66 percent of the marine environment and three-quarters of the land-based environment have been altered by human actions.

Also, almost 75 percent of freshwater resources and more than a third of the world’s land surface is now devoted to crop or livestock production. Since 1980, plastic pollution has increased tenfold with 300-400 million tons of heavy metals, solvents, toxic sludge and other waste from industrial facilities being dumped into the world’s waters every year. 

Sir Robert Watson, IPBES Chair, stated that the health of ecosystems is deteriorating more rapidly than ever. “Through ‘transformative change’, nature can still be conserved, restored and used sustainably – this is also key to meeting most other global goals. By transformative change, we mean a fundamental, system-wide reorganization across technological, economic and social factors, including paradigms, goals, and values,” he said. 

However, there is one thing being left out in conversations in biodiversity that can essentially save our planet: mountains. 

How Mountains Create Biodiversity

Mountains occupy almost a quarter of global land surface. Compared to lowland areas, they are richer in species and their peaks form isolated ‘islands’ of suitable habitat. Reports show that mountains are home to 12 percent of the world’s population. There’s an extremely high level of biodiversity in these places because they compress a wide range of climates and ecosystems into a relatively small area. In fact, 50 percent of the 34 global biodiversity hotspots are found in mountain areas.

However, it has been a mystery why mountains are important in creating high species richness. A 2018 study conducted by four scientists from the University of Amsterdam has finally answered the question. According to Phys.org, a science, research and technology news aggregator, the researchers applied statistical models to biological, geological and climatological datasets from across the world. 

Researcher Daniel Kissling stated that they linked the species richness of birds, mammals, and amphibians to global datasets of temperature, precipitation, erosion rates, relief, and soil composition. They were surprised to discover that a significant relationship between biodiversity, erosion history, relief, and number of soil types. One of their key findings is that mountain building continuously reshapes the landscape of our planet through a process of uplift and erosion. 

Also, mountains play an integral role in creating habitat heterogeneity in an elevational gradient. Carina Hoorn, the senior author of the paper, stated that the complex connection between growing mountains and climate generates plenty of opportunities for the creation of new species. "Although climate and ruggedness of the terrain were previously thought to be the principal cause for mountain biodiversity, our global synthesis now makes clear that geological history plays a paramount role in this process," Horn said. 

Mountains occupy almost a quarter of global land surface. Compared to lowland areas, they are richer in species and their peaks form isolated ‘islands’ of suitable habitat / Photo by: Buddhika Tharanga via Wikimedia Commons

 

Mountains Are Hotspots of Biodiversity

Mountain ecosystems have been known as hosts to higher species richness and levels of endemism. While they only cover 25 percent of Earth’s land area, they are home to more than 85 percent of the world’s species of amphibians, birds, and mammals. In fact, many of these animals are only found in the mountains. However, scientists have been puzzled by the global pattern of mountain biodiversity and the fascinating high richness in tropical mountains.

A recent study conducted by researchers from the Center for Macroecology, Evolution, and Climate (CMEC) at the GLOBE Institute of the University of Copenhagen, in collaboration with scientists from Oxford University, Kew Gardens, and University of Connecticut, has explored why mountains are so biologically diverse. Co-leader Michael K. Borregaard explained that the most species-rich mountain region in the world is that diverse due to the uniquely heterogeneous mountain climates. Many mountain regions capture roughly half of the world's climate types in a relatively small region. 

Mountain ecosystems have been known as hosts to higher species richness and levels of endemism / Photo by: Irrational pi via Wikimedia Commons

 

According to the scientists, mountain richness can be explained by the interaction between geology and biology. They discovered that high diversity is in most tropical mountains tightly linked to bedrock geology. The exceptional environmental conditions that drive localized adaptive change in plants is due to the tropical mountains that have soil originating from oceanic bedrock. As a result, plants can adapt to unusual soils that can ultimately contribute to the shape of global patterns of biodiversity.

Science Daily, an American website that aggregates press releases and publishes lightly edited press releases about science, reported that high biodiversity in mountains is connected to the geological dynamics of mountain building. The geological process provides ample opportunities for evolutionary processes to act. 

“Mountains, with their uniquely complex environments and geology, have allowed the continued persistence of ancient species deeply rooted in the tree of life, as well as being cradles where new species have arisen at a much higher rate than in lowland areas, even in areas as amazingly biodiverse as the Amazonian rainforest,” Professor Carsten Rahbek, lead author, said. 

Indeed, mountains are a great help in creating and maintaining biodiversity on our planet. If these mountains are properly cared for and conserved, there’s a high possibility that they can save Earth from climate change.