The high and mighty Himalayas: A biodiversity hotbed facing significant challenges

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This article was originally published on The Conversation, an independent and nonprofit source of news, analysis and commentary from academic experts. Disclosure information is available on the original site.

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Authors: Nita Dyola, Post-doctoral fellow, Département des Sciences Fondamentales, Université du Québec à Chicoutimi (UQAC); and Sergio Rossi, Professor, Département des Sciences Fondamentales, Université du Québec à Chicoutimi (UQAC)

The Himalayas are home to a vast diversity of species, consisting of 10,000 vascular plants, 979 birds and 300 mammals, including the snow leopard, the red panda, the Himalayan tahr and the Himalayan monal.

The region represents a huge mountain system extending 2,400 kilometres across Nepal, India, Bhutan, Pakistan, China, Myanmar and Afghanistan. It has a number of climate types and ecological zones, from tropical to alpine ecosystems including ice and rocks in the uppermost zone. All these ecological zones are compressed within a short elevation span.

The Himalayas — along with the related Tibetan Plateau — provide considerable ecosystem services and as the “third pole” are also the source of most of Asia’s major rivers, a fact that has earned it the additional moniker of “the world’s water tower.”

It is of urgent importance that these fragile ecosystems are conserved and protected.

Flourishing diversity

How do mountains, and the Himalayas specifically, support such biodiversity? Put simply, the steep differences in elevation provide unusually large temperature bands — and environmental conditions — that help support a diversity of life.

In the central Himalayas, the average temperature changes by about one degree Celsius every 190 metres up or down. By comparison, in the northern hemisphere, the same degree of temperature change occurs roughly every 150 kilometres — and every 197 kilometres in the southern hemisphere — along a north-south line.

While hiking on the mountains, one can easily notice the distinct changes in vegetation within a fairly small change in elevation. The biodiversity changes are most noticeable where the treeline gives way to alpine grasslands.

During the course of our recent comprehensive field study in Kangchenjunga, Nepal we recorded approximately 4,170 trees belonging to 126 different species every 100 metres in elevation change from 80 to 4,200 metres above sea level. We also found that the middle elevations from 1,000 to 3,000 metres above sea level had higher levels of biodiversity compared with the mountain top and bottom.

Such high diversity is the result of a dynamic balance between warm temperatures and abundant precipitation.

Forests as carbon sinks

Trees are one of the main carbon sinks in the Himalayas, storing about 62 per cent of total forest carbon. The cooler forest soils in the northern biomes, including boreal forest and tundra, allow for further carbon storage as undecomposed organic matter.

Biomass represents the overall carbon stored in plants.

Our study found that communities with higher plant diversity produce more biomass and thus store more carbon. Different species have different needs and ways of using resources such as water, sunlight and nutrients.

In species-rich communities, each one can more efficiently profit from the resources available, leading to higher exploitation and larger biomass accumulation. For example, where there are many different tree species, each can occupy different parts of the canopy and their roots can utilize different soil layers, reducing the competition among individual trees.

At higher elevations, where the climate is harsh and nutrients are scarce, species can help each other rather than compete for resources. This co-operation, called facilitation, can promote positive species interactions and enhance growth and biomass production.

The dilemma

Like other regions of the Earth, the Himalayas are currently exposed to a rise in temperature. The warming rate in this area is three times higher than the global average, with an estimated increase of 0.6 C per decade.

These warming conditions force many species to move towards cooler sites at higher elevations. However, this movement can increase competition for resources and space, particularly at higher elevations, leading to biodiversity risks.

Human-caused climate warming and increasing deforestation have also fuelled an invasion of non-native species. For example, the crofton weed poses a real risk to the native Himalayan pine trees (Pinus roxburghii).

In the long run, the exclusion of native and dominant species could dramatically impact people’s livelihood and biomass accumulation in local forests.

The local human communities of the Himalayas rely largely on natural resources. As such, the desired and urgent priority of biodiversity conservation can be seen as at odds with local development.

It is crucial to adopt respectful approaches that consider both the ecological needs of these fragile ecosystems and the economic interests — and socio-cultural perspectives — of the people who live there. Solutions must originate from a serious and deep discussion among the major players, representing global and local interests.

Himalayan biodiversity matters

The Himalayas are one of 36 biodiversity hotspots, with around 3,160 rare, endemic and sensitive plant varieties that hold special medicinal properties.

Conserving its biodiversity is crucial in maintaining a wide range of ecosystem services. The mountains help lessen the amount of carbon dioxide in the atmosphere by sequestering carbon within plant biomass and is home to a beautiful array of wildlife.

The Convention on Biological Diversity, an international organization dedicated to preserving biodiversity worldwide, has identified the Himalayas as one of its priorities.

By preserving this magnificent and delicate landscape, we can ensure that future generations can enjoy its beauty and wilderness and benefit from the services that these ecosystems provide. Thus, the conservation of biodiversity in the Himalayas is a matter of concern for both global and local communities.
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Nita Dyola received funding from the National Natural Science Foundation of China (Grant No. 42030508) for fieldwork in the central Himalayas. In Canada, she benefits from the Merit Scholarship for Foreign Students by the Fonds de Recherche du Québec – Nature et Technologies (FRQNT) and the Mitacs Globalink Research Award for research.

Sergio Rossi receives funding from NSERC, FRQNT and MRNF.
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This article is republished from The Conversation under a Creative Commons license. Disclosure information is available on the original site. Read the original article: https://theconversation.com/the-high-and-mighty-himalayas-a-biodiversity-hotbed-facing-significant-challenges-226203