The first indication in Thimphu that winter is behind us and spring has arrived is the bursting of flower buds of apricot trees towards the end of February, followed by peach, pear and apple trees in March and April. Every year, these attractive tree-full white and pink blossoms cheer up and buoy up the residents with tons of happiness and joy.

Plants are sensitive to climate change and they respond in a variety of ways. For instance, due to climate change, many spring events are said to be occurring earlier and autumn events happening later than they did in the past. Also, while some plants have been found to move upward to cooler, higher elevations, some plants have also been found to move downward toward warmer, lower elevations.

Such information is helpful to understand which species are capable of adapting to climate change and which ones may be in trouble. The information is also helpful in practical terms to farmers, horticulturalists, gardeners, foresters and others to understand how the species they rely on are changing, and predict threats they might face in the future. In order for people to know and monitor how climate is changing in their immediate environment, more and more countries today are incorporating phenology as a national indicator of climate change, in addition to international indicators like the CO2 in the atmosphere, air temperature over land and oceans, polar sea ice sheets, glaciers and sea levels.

Phenology is the study of the effects of the seasons on plants and anim

Photos taken on same date for 4 years of flower buds of an apricot tree in Thimphu (one year data missing). There is no visible difference in the timing of flowering, perhaps a record of over 10 years may yield important information.

Photos taken on same date for 4 years of flower buds of an apricot tree in Thimphu (one year data missing). There is no visible difference in the timing of flowering, perhaps a record of over 10 years may yield important information.

als, for instance when the first buds appear, when the first flowers appear, when the fruits ripen and when leaves change colour and drop in the autumn. Similarly, when do the insects, migratory birds and animals arrive?

Observing these life events is perhaps the simplest process in which to track changes in the plant and animal’s response to climate change. The climate scientists say changes in the timing of plant and animal phenology is one of the most sensitive indicators of the local effects of global climate change. Many naturalists in the past have left records of their observations of plants and animals. Matching such historical observations with more recent ones has allowed climate scientists to identify shifts in plants’ and animals’ response to climate change.

The earliest and longest phenological observations was by one English naturalist Robert Marsham, and his successive generations who kept systematic records of “Indications of Spring” from 1736 to 1958. Other English naturalists of the time also reported seasonal events of more than 400 plants and animal species. These works show, the first leafing date of oak in Britain appears to have advanced by about 8 days; the first flowering date of 385 British plant species has advanced on average by 4.5 days; and annual plants and insect pollinated plants flower earlier than perennials and wind pollinated plants.

In Bhutan, there are over 5,600 species of plants, 200 species of mammals and 678 birds. Currently, we don’t have in the country long term measurable phenological data for our many plant and animal species except maybe for the arrival and departure dates of the Black-Necked cranes. We have instead anecdotal narratives such as Bhutan always had clear four seasons but now there is blurring of the seasons taking place, monsoon has become erratic, alpine plants will go extinct as they have no escape route in a warming environment, and farmers are shifting to earlier rice planting. An anecdotal narrative is considered the least type of scientific information. Researchers may use anecdotal narratives for suggesting new hypothesis but never as validating evidence.

The task of observing, recording and reporting on the thousands of plants and animals goes beyond what any one institution or person alone can perform as it is a subject that requires data to be gathered or processed over long periods of time or wide geographical areas. Therefore, the way around it is to engage the public in so called citizen science.  Citizen science refers to public participation in scientific research in which members of public participate in the process of scientific investigations such as asking questions, collecting data and/or interpreting results.  With simple introduction to the subject, hundreds of volunteers and enthusiasts can take up the task as a hobby or past time to observe how and when plants in gardens, parks, streets, offices campuses, towns, mountains or valleys are changing with seasons, thus helping build a scientific knowledge base.

Some motivated by just wanting to make a contribution to science, some because of the love for nature and others as a recreational activity, the citizen scientists have formed or are coming together to form phenology networks. The important phenology networks in the world include the UK Phenology Network, USA National Phenology Network, and European Phenology to name a few. As an example, the US NPN has over 5,000 citizen scientists monitoring 815 plants, 67 insects, 40 amphibians, 133 birds and 35 mammals. And, the North American Bird Phenology Program has the arrival and departure date records for over 870 bird species dating back to 1880.

Many may not be aware that Bhutan too has a phenology network started in 2014 by the Ugyen Wangchuck Institute for Conservation and Environment based in Bumthang. The network presently covers 17 schools representing all major ecological zones in the country. The teachers and students have been trained to observe and record the phenological development of the plants and animals in their school compounds. The Network soon plans to include a citizen science programme where the general public will be invited to be its members.

Understanding climate change requires looking at the longer term records. In fairness and duty to future generations where the climate change challenge will only be more acute and intense than today, we must pass down to them information of our time. Imagine we have dates on onset of spring gradually moving up from hot sub-tropical region to cool temperate to cold alpine, and autumn leaf falls from north down to south, how scientifically well informed the Bhutanese society will be of its natural environment. Mobile phone technology today makes citizen science in the area of phenology an almost effortless venture, and all that is required is to pay little attention to the wonders of nature around us as the seasons change.

Contributed by

Dr Phuntsho Namgyel

Bhutan-eForest Group


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