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GIS Analysis for Natural Ecosystem Preservation: Investigation on the Japanese Crane's Habitat -- Koichi Hirata


GIS analysis for natural ecosystem preservation

Investigation on the Japanese crane°«s habitat

KOICHI HIRATA

PASCO CORPORATION


Natural ecosystem preservation means maintenance of an abundance of nature, preservation of endangered species, keeping of biodiversity, and so on. Recently there have been increasing reports about research of ecosystem preservation using remote sensing or GIS (Geographic Information Systems) spatial analysis. He introduces a case that made a study ranging from expansion of nesting grounds to keeping of species and increase of population by analyzing the environment of Japanese crane°«s nesting grounds, which are one of the endangered species.

Life cycle of Japanese cranes

Though Japanese cranes living in the eastern Hokkaido are said to have ranged over a wider area including Kanto region in the Edo period, they were once said to have extinguished because of the decrease of wetlands caused by land developments and over hunting aiming their feathers. Afterwards their population has recovered up to 781 through careful feeding and preservation by people living around Kushiro wetlands, which was reported in the census in January 2002. However, the increase rate of their population tends to show a slowdown maybe due to the environmental deterioration of their habitats.

Japanese cranes gather around wetlands and lay eggs from March to May. They bring up their young birds between August and September. Afterwards they leave wetlands and live on the peripheries of wetlands till the next spring while they rear their children. They have a wide action area shown in recent reports that describe that they fly between Hokkaido and the Northern Territories. They have strong conjugal affection as they continue to live together once they become a pair.

GIS spatial analysis

Research direction of GIS in Japan had almost been development of the multi-purpose digital mapping system for local governments°°that alters paper maps. Recently there have been increasing reports using the GIS spatial analysis functions such as °»Overlay°… in the field of ecology (generation of a new map layer by superimposing a map information over another map layer) and °»Buffering°… (data extraction using the distance from a certain point/line/polygon on the map layer.)

Here, I developed a method that in based on the concept of Rule Based GIS to a rule in spatial phenomena. It is similar to the field of spatial statistics which is in trend now.

Supposition of habitats selection

I suppose the condition of habitats selection of Japanese cranes in Kushiro wetlands as following: 1) topological condition: altitude, inclination, and direction of slopes, 2) favorable condition: wetlands, water system, and development regulation, 3) unfavorable condition: roads, buildings, and changes of land cover.

I obtained data from Prof. Hiroyuki Masatomi, a specialist of the Japanese crane°«s research (Hokkaido College, Senshu University,) that described the plotted map of Japanese crane°«s habitats, and expressed them numerically. I evaluated the topological condition, favorable condition, and unfavorable condition after superposing this habitats data over numerical map data which is the digital map of a 1:25,000 scale and LANDSAT data. The data was buffered from the habitat points and the selection condition was defined by the 90% of habitats distance.

Results of analysis

The selection conditions in which significant relationships cannot be found were topological condition, development regulation, and changes of land cover. In overall flat wetlands, topological condition was supposed to be necessary as a whole. There seemed no relationship between the regulation about artificial development of natural parks and changes of land cover because these conditions didn°«t seem to matter for Japanese cranes (Figure 1).

The following requirements were extracted by modeling the conditions of habitats selection.

1) It should be wetlands

2) It should be more than 100 m distant from roads

3) It should be more than 360 m distant from buildings

4) It should be within 260 m from water systems

Water systems as feeding places and wetlands as places to hide had been supposed in advance but it was surprising that vicinity of roads were selected (Table 1).

The more influential element was home range. Japanese cranes keep their own home range at their feeding season, and keep the distances between other pairs guarding their nests not to be stressed each other. This is called home range in a temporal meaning, and the radius of their home range was more than 700 m. In other words, the distance between nests needs to be more than 1.4 km (Fig. 2).

Habitats that are possible to live in the Kushiro wetlands were extracted by using these models. The area of wetlands is decreasing year by year because of the wetlands dryness and artificial development. The result of the model analysis agreed with the condition that Japanese cranes tend to select proximity of roads or buildings as their habitats (Fig.3).

To protect the habitats of Japanese cranes

Afterwards, such an analysis was also carried out around the Furen Lake in east Hokkaido. In this area, Japanese crane°«s habitats are distributed around the Furen Lake which is a sub-national park. It°«s different from the Kushiro wetlands on the viewpoint that Kushiro wetlands are full of wetlands while Furen Lake has small wetlands around the residential areas and fields. Japanese cranes mainly inhabit around the small wetlands. They chose their habitats near the wetlands as a requirement.

It is said that young birds aren°«t hatched for a few years in the new habitats along the Tokachi River. Japanese cranes are a good subject of a photograph because of the beautiful appearance, their affectionate dance, and their tremendous attachment to family. But if they are taken pictures in the breeding season, they tend to give up their nests.

It is said in the inheritance filed that the population which is necessary for the preservation of species is 1000 or 2000. I don°«t think that I°«m the only one who hopes to keep their habitats and preserve the environment that Japanese cranes can devote to breeding.

References

1) Hiroyuki Masatomi, Japanese Crane Handbook, The Hokkaido press, 2000

2) Koichi Hirata and Hiroshi Murakami, Extraction of Japanese Crane°«s Habitat Selection and Analysis of the Habitat Environmental Change Using GIS, Proceedings of JSPRS °«96, pp. 169-172, 1996

3) Hiroshi Murakami and Koichi Hirata, Potential Nesting Site Analysis of Red-cranes using GIS, International Archives of Photogrammetry and Remote Sensing, Vol.XXXI, Part B4, Vienna, 1996

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