Yale Environment Review

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New science offers insights into the wisdom of Tibetan nomads

Image: Kuncho Palzang

Mua, Junpeng; Yuling Zenga; Qinggui Wua; Karl J. Niklasc; and Kechang Niu. “Traditional grazing regimes promote biodiversity and increase nectar production in Tibetan alpine meadows,” Agriculture, Ecosystems and Environment, Volume 233, 3 October 2016, Pages 336–342, DOI: 10.1016/j.agee.2016.09.030

Tuesday, April 4, 2017

The world has long attributed Tibetan wisdom to the Buddhist monks and their teachings, but largely ignored the wisdom of the nomads. Recently, scientists have proven that traditional grazing practiced by these nomads are crucial for Tibetan rangelands, promoting plant diversity and nectar production.

High up in the Tibetan Plateau nomads have moved their herds from summer pasture to winter pasture rotationally to avoid both overgrazing and grazing exclusion, sustainably managing rangelands for thousands of years. This practice renewed grasslands, improved wildlife habitat and diversity, and protected the headwaters of Asia’s 10 major rivers. They have also maintained a healthy environment and secured local economic stability; the rich natural resources enabled self-sufficiency. Over the past three decades, however, changes in the region — including altered land use practices — have threatened the stability of these ecosystems. It seems that policy makers disregarded the wisdom of the nomads’ thousands-year-old practices. A study recently published in the journal Agriculture, Ecosystems and Environment comparing plant diversity and nectar production in the Tibetan Plateau offers evidence of this wisdom. In the study, an international team of scientists led by Kechang Niu from the Nanjing University examined three alpine meadows that each had plots that varied from ungrazed to heavily grazed. The study looked both at the individual plant and plant “community” level. Individual nectar production was calculated per flower, per flower cluster, and per entire plant. Plant community nectar production was calculated as the total nectar production from the flowers of all plants within a square meter plot. The team found that nectar production and species richness at all ecological levels was significantly higher in lightly and moderately grazed plots compared to heavily grazed and ungrazed plots. The scientists suggested potential reasons for their findings: plants in ungrazed plots grow tall in order to compete for light, and in heavily grazed plots plants allocate resources to resprout, in both cases reducing resources for flowering. Traditional light and moderate grazing, on the other hand, reduce light competition and reduce the need to allocate resources to stem and leaf biomass, leaving greater resources for flowering. For individual plants, traditional light and moderate grazing practices promote earlier flowering and increase the number of flowers and flower clusters. For plant communities, these traditional practices eliminate competition between the flowering plants and grasses, which leads to an increase in flowering plants. In turn, these large communities of flowering plants attract an abundance of pollinators like bees and butterflies. Changes in how rangeland is managed in Tibet, and around the world, affect the ecosystems and the people. The scientists emphasized that while it is important to avoid overgrazing, that is not an excuse to not graze at all. Neither of these extremes are effective management strategies. Instead, traditional light and moderate grazing practices should be recognized as the best management approach to keep rangeland ecosystems productive.