Climate Witness: Masayuki Kurechi, Japan

Posté le 30 avril 2010

Masayuki Kurechi, a member of the Japanese Association for Wild Geese Protection, has continued to make observations of Greater White-fronted Geese for over four decades. He has begun to notice the changing weather patterns are affecting the Greater White-fronted Geese.

In the autumn, Greater White-fronted Goose, a large waterfowl, comes to visit waterfront areas in Japan. Since becoming fascinated by this species in his university years, Masayuki Kurechi, a member of the Japanese Association for Wild Geese Protection, has continued to make observations of Greater White-fronted Geese for over four decades. He has lived near Izu-numa marsh in Miyagi prefecture, the largest stopover site for geese in Japan, watching over their life. He points out that the number of geese visiting the area around Izu-numa is increasing year by year, and that the period of their wintering is gradually becoming shorter. He is concerned over the possibility that global warming is having a major effect on the ecology of the geese.

English | 日本語

Soon, I will have been living in Miyagi prefecture for four decades. While running a private tutoring school, I have observed the life of Greater White-fronted Geese that spend the winter in various places in northern Miyagi, including Izu-numa.

Izu-numa, a wetland with a rich natural environment, is registered under the Ramsar Convention. Many Greater White-fronted Geese spend the winter there. However, since 1990, their numbers have rapidly increased, and overconcentration has emerged as a problem.

Moreover, various changes can be observed in the behavior pattern of the geese. I am concerned that their breeding grounds may be lost before too long if global warming continues unabated.

Greater White-fronted Geese are Sensitive to Environmental Changes

I was born and raised in Hiratsuka, Kanagawa prefecture. I never saw any greater white-fronted geese there. After entering university in Sendai, the capital city of Miyagi prefecture, I visited Izu-numa with a map in hand. This was my first encounter with the geese.

It was winter, in a rice field, when I saw them for the first time.

A flock of about 1,000 birds were picking at fallen ears of rice. When I took a step toward them, they all looked up at once in alarm, and after another step, the flock took wing, filling the entire sky. I was very surprised that so many large birds were living in the wild, and was completely captivated by their powerful wild presence.

Greater White-fronted Geese are very cautious birds. They are also extremely sensitive to environmental changes.

Since they cannot survive without a rich natural environment, they leave a place when they feel uncomfortable, never to return.

They once ranged across Japan, but their habitat has rapidly shrunk due to development following World War II. Conversely, we can determine what kind of problems the environment has at present by watching the behavior of the geese. This is the kind of bird they are.

The Timing of Their Arrival is Changing

Greater White-fronted Goose, a waterfowl, cannot survive if the marshes where they roost at night are completely covered by snow or ice. The summer is short in their breeding grounds near the Arctic Circle, and snow begins to fall late in August. Thus, when this season comes the geese fly south to places that remain unfrozen.

After departing from Lake Pekulneyskoye in Russia, they fly southward, passing over the Kamchatka Peninsula, Hokkaido and Akita prefecture, finally arriving at their destination, their wintering spots of Izu-numa. Their flight takes them 4,000 km. In October, the flocks begin to arrive in the area around Izu-numa, and their numbers gradually increase.

However, in recent years they have begun to arrive later and later. Also, while they used to leave the area and head north around February or March as spring approached, they are beginning to leave earlier. In other words, they spend less time in the area around Izu-numa than they used to.

Further, a phenomenon of “stopping points” becoming “wintering spots” has been observed.

In the past, Otomo-numa in Akita prefecture was only a “stopping point” where the geese headed for Izu-numa would stop during their migration. However, in recent years, some of those geese can be observed spending the winter at that marsh, without moving further south.

Greater White-fronted Goose can only survive in places where the average temperature during midwinter is above freezing, since the marshes freeze over when the average temperature drops below zero.

The average temperature of Otomo-numa used to be below freezing during the midwinter. However, according to data from recent years, it has exceeded zero degrees.

The lighter snowfall and availability of unfrozen marshes have significantly changed the behavior of the geese.

The geese, which were once only seen in autumn and spring, now continue to stay through the winter. This phenomenon can be seen not only in Akita but also in Hokkaido and other places as well.

The Concentration of Greater White-fronted Geese in a Single Place

When I saw the geese for the first time, there were around 5,000 birds around Izu-numa. The Japanese government designated them as a protected species in 1971. Hunting was prohibited and protection was started. Since then, their numbers have gradually increased. Their numbers have grown rapidly since 1990, and in 2010, more than 100,000 geese spent the winter in the northern part of Miyagi prefecture, in places such as Izu-numa, Kabukuri-numa and other marshes.

This explosive increase in their numbers seems to go far beyond the level that could be expected from protection. In my opinion, one reason is the effect of global warming on the breeding areas.

Greater White-fronted Geese breed and nest in tundra areas near the Arctic Circle. They breed on the ground in marshes where the rivers and swamps create a complicated landscape.

If the early spring thaw begins earlier than usual due to the effects of global warming, the geese can make more nests, and thus more goslings are born.

Also, since geese are herbivorous, an earlier thaw helps the goslings grow by increasing the amount of grass that they can feed on.

In this way, the rise in air temperature seems to lead to an increase in the population, resulting in larger numbers of the geese migrating to the area around Izu-numa.

However, the rapid increase in their population brings about problems of its own.

One is a problem facing the birds themselves. Despite the increase in their population, the places suitable for overwintering are limited, and they can become over-concentrated in few habitats.

Also, if water contamination occurs in a marsh such as Izu-numa or Kabukuri-numa where the birds are concentrated, they can be wiped out overnight. Infectious diseases occurring among densely packed birds also pose a serious risk.

Another problem is the relationship between the birds and human beings.

During the daytime, the geese feed on foods in arable lands such as rice paddies. But if too many birds flock in a single place, the damage to agriculture may become a big problem.

Although some cities in the northern part of Miyagi prefecture have established ordinances that provide compensation for damage to agriculture caused by geese, ducks and swans, an excessive concentration of birds will threaten their symbiosis with human beings.

To deal with this situation, a project to encourage the flooding of rice paddies during the winter is being carried out with the help of farmers around Kabukuri-numa. This project seeks to create symbiosis between human beings and Greater White-fronted Geese, and to promote decentralization, by flooding rice fields after the harvest, thereby creating an environment similar to marshes. Local people began to see the paddy fields that the geese use as valuable sites with rich biodiversity, and this consciousness is spreading.

Greater White-fronted Geese as Harbingers of Environmental Crisis

At a glance, the influence of the global warming may appear to be desirable since the population of the geese is growing.

However, it is projected that the tundra breeding areas of the geese that migrate to Japan will be significantly affected by the influence of global warming. It is said that tundra will rapidly becomes wooded if global warming continues (the permafrost will melt and trees will be able to spread their roots).

If this happens, the geese will lose their breeding grounds, and as a result, the flocks will dwindle or disappear from the local area.

I believe it is important to halt current warming as soon as possible in order to protect the future of the geese.

Incidentally, the Chinese character for goose, “雁” depicts a “human” (“イ”) and “bird” (“隹”) living together in “a house” (“厂”). This signifies that geese, which care for their families, are a friendly species for human beings and are deeply involved in the lives of people.

Though it is very difficult to visually confirm the phenomenon of global warming, I think it is important to be conscious about this problem and to grasp it by coexisting with the geese, which are very sensitive to changes in the environment.

Global warming is an issue that we human beings created. I believe that we need to recognize it as everyone’s problem and take necessary actions.

Scientific Basis

According to Summary for Policymakers of the Contribution of Working Group II(WG II) to the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change(IPCC) (2007), recent warming is strongly affecting terrestrial and marine ecosystems, and the earlier timing of spring events, such as bird migration and egg-laying, as well as pole-ward and upward shifts in ranges in plant and animal species have been observed in the Northern Hemisphere. Phenomena such as the transformation of stopover points into wintering sites and the earlier timing of migration from wintering spots to the north in the spring that has been observed since the 1990s among Greater White-fronted Geese (Anser albifrons) spending the winter in the area around Izu-numa coincide with these description by the IPCC. Moreover, some papers have reported geese spending the winter in Otomo-numa, a former stopover point in Akita prefecture (1) and that in January 2007, due to the warm winter, the flocks left the northern part of Miyagi prefecture where they spent the winter and moved northward to Otomo-numa earlier than usual (2).

At this point, it is not clear whether the rapid increase since the 1990s in the population of geese wintering in the area around Izu-numa is an effect of the warming in the breeding areas in Russia (increased reproduction rate). However, data on air temperature collected by polar meteorological stations in northeast Russia between 1933 and 2000 show that the air temperature in the breeding areas has been rising (3). Chapter 15 “Polar regions 15.2.1” in IPCC AR4 WG II states that “surface air temperatures in the Arctic have warmed at approximately twice the global rate for several decades.” Further, there have been observations of reductions in the duration of river and lake ice, warming of permafrost and changes in vegetation (a transition from grasses to shrubs), showing that the effect of the global warming is already manifesting itself in the Arctic region.

As stated by Mr. Kurechi, we need to direct our attention to the changes not only of the wintering sites and stopover points, but also in the breeding areas when considering the effect of global warming to migratory birds such as Greater White-fronted Geese. After all, migratory birds, which fly back and forth among breeding areas, stopover points and wintering sites, are significantly affected by their entire habitat environment. Box 4.5 in Chapter 4 in IPCC AR4 WG II states that “Migratory species can be affected by climate change in their breeding, wintering and/or critical stopover habitats” and that “Models project changes in the future ranges of many species.” For example, it is predicted that a rise of two degrees Celsius in the air temperature of the earth will cause a decrease in the breeding area of many waterfowls that breed in the Arctic region, such as snipes, plovers and ducks, by 45% and 50% at the maximum (4).

According to the projected vegetation map for the Arctic region in IPCC AR4 (5), Russian tundra, which constitutes the breeding area for the geese, will be transformed to boreal forest in the period between 2090 and 2100, leading to the possibility that this breeding area will be destroyed or disappear. Although the number of Greater White-fronted Geese wintering in Japan is rapidly increasing today, we need to watch over the actions and behaviors of migratory birds, including geese, and try to minimize the effect of global warming.

(1) Shimada T., Hatakeyama S., Miyabayashi Y., and Kurechi M., 2005: Effects of climatic conditions on the northward expansion of the wintering range of the Greater-fronted Goose in Japan, Ornithological Science, 4, 155-159
(2) Shimada T, 2009: Current status and distribution of Greater White-fronted Goose in Japan, Short Communication, Ornithological Science, 8, 163-167
(3) The Japanese Association for Wild Geese Protection, The Research on the Effect of the Global Warming on Migratory Geese, Achievement Report on JFGE Granted Project in 2002, 2003
(4) Folkestad, T., M. New, J.O. Kaplan, J.C. Comiso, S. Watt-Cloutier, T. Fenge, P. Crowley and L.D. Rosentrater, 2005: Evidence and implications of dangerous climate change in the Arctic. Avoiding Dangerous Climate Change, H.J. Schellnhuber, W. Cramer, N. Nakicenovic, T.M.L. Wigley and G. Yohe, Eds., Cambridge University Press, Cambridge, 215-218.
(5) Figure 15.3 in Chapter 15 “Polar regions” of the Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, p. 659.

* For details of Mr. Kurechi’s account, please refer to pp. 131-148 of Ondanka no seibutsu tayosei (Biodiversity and the Global Warming) (Kunio Iwatsuki and Akiko Domoto eds., Tokyo: Tsukiji Shokan, 2008) [Japanese] or Ganyo watare (Migrate, Geese) (Masayuki Kurechi, Tokyo: Doubutsu Sha, 2006) [Japanese].

All articles are subject to scientific review by a member of the Climate Witness Science Advisory Panel.