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DEVELOPING ECOLOGICAL NETWORKS BETWEEN URBANWOODLANDS IN AN INDUSTRIAL AREA: A CASE STUDY INTHE OSAKA METROPOLITAN AREA OF JAPANTomohiro Ichinose1 and Wakako Miyata2
1

Institute of Natural Environmental Sciences, University of Hyogo
2Sekisui Exterior Co, Ltd.

ABSTRACT
We proposed an ecological network plan for part of the Osaka metropolitan area based on ananalysis of satellite image data using a geographical information system. Vegetation cover wasidentified using the normalized difference vegetation index for SPOT4 data captured in June
2003. Large woodlands and many smaller woodlots were located in a mountainous area (theRokko Mountains) in the northwestern part of the study area, but there was little vegetation
cover elsewhere. Small woodlots (0.2 ha or larger) were selected and 500-m buffer zones
around them were created to identify locations where it was necessary to connect the Rokko
Mountains and the project area along the Mukogawa River, with the goal of helping forest birds
to move into the area. However, a large gap in the northern part of the project area should beremedied; we propose a planting plan for a small factory in the area.
Keywords: ecological network, satellite image data, industrial area, afforestation, forest birds

INTRODUCTION
Urban growth has fragmented and isolated wildlife habitat, especially woodlands. As a result,
growth has decreased biodiversity in urban areas. On the other hand, many industrial areas wereabandoned at the beginning of the 1990s in advanced countries as a result of the decline ofheavy industries. Many woodlands have been restored or created in these areas in the past
decade (Kowarik and Körner 2005).
However, many of these new woodlands are isolated from other woodland habitats and should
be connected by ecological networks to permit travel between habitats by wildlife and toconserve biodiversity in urban and industrial areas. In Japan, the population has been decreasing
since 2004 and the number of abandoned areas have increased in urban and industrial areas.
Many large sites have been abandoned, especially on reclaimed waterfronts, when heavy
industries moved to other Asian countries or reduced the size of heir plants. These sites wereoften formerly sandy beaches or tidal flats, but it may be so difficult to restore former habitats
on these sites that we must sometimes choose other options.
Currently, a large project has been initiated to establish large semi-natural woodlands in part of
the Osaka metropolitan area in Japan. The project area is isolated from surrounding naturalwoodlands, thus it is necessary to develop ecological networks to conserve biodiversity in thearea. In this paper, we describe a proposed ecological network plan for the area based on theanalysis of satellite image data using geographical information system software, and a greeneryplan for a small abandoned factory.
We selected birds as the indicator species for the plan because we can find many bird species
even in urban and industrial areas, they can fly between habitats, and they are one of the mostpopular taxa among citizens.

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T. Ichinose and W. Miyata / IUFRO 8.01.03 Landscape ecology

MATERIALS AND METHODSSTUDY AREA
The project area (about 1000 ha) is located in Amagasaki City, in the Osaka Bay Area of HyogoPrefecture (Figure 1). The area has been used by heavy industry since the 1960s on reclaimed
lands. Presently, there are many abandoned industrial areas.
The government of Hyogo Prefecture has begun a project called the “Amagasaki Forest Plan forthe 21st Century” that aims to increase the vegetation cover from 4% to 30% over the next 100
years. The first part of the project will start in 2006 at a 29-ha site abandoned by the iron andsteel industry. Because the area is located in the Osaka metropolitan area, the area is surroundedby dense residential and commercial areas and there are few woodland areas and open spaces
around the site.

ANALYSIS OF SATELLITE IMAGE DATAVegetation cover in the project area was identified using the normalized difference vegetationindex (NDVI) for SPOT4 data captured on 3 June 2003:
NDVI = (Near IR – R)/(Near IR + R),(1)

where Near IR represents the value in the near-infrared band and R represents the value in thered band. We conducted ground-truthing in the winter and summer of 2005 to correlate theNDVI values with the presence of vegetation. Large woodlots (! 2 ha) were identified and 200m buffer zones were created around their boundaries in the software. Ichinose and Katoh (1998)
indicated that a woodlot at least 2 ha in size is necessary for breeding of passerine species thatprefer woodland habitats. Hashimoto and Natuhara (2002) showed that at least 32% of the area
within a 200-m radius of existing woodlots also had to support woodland to achieve aprobability of occurrence of the great tit (Parus major) equal to 0.5 or better.
Small woodlots (! 0.2 ha) were also identified, and 500-m buffer zones around these woodlots
were created in the software. Ichinose (2002) reported that woodlots at least 0.2 ha in size arenecessary to provide habitat for overwintering species that prefer woodland. In addition, theproportion of woodland within a 500-m radius of these small woodlots is an importantenvironmental factor for overwintering birds (Ichinose and Katoh 1998). Gaps in ecological

Patterns and processes in forest landscapes. Consequences of human management
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networks between large woodlands and small forested sites were identified based on ouranalysis of the gaps between these buffer zones.
PROPOSAL FOR PLANTING AT A FACTORY
We focused on a large gap in the ecological network in the northern part of the project area,
where many small factories are concentrated. An environmental conservation bylaw ofAmagasaki City states that an owner must reserve 10% of an industrial area for planting if thefactory covers 1 ha or more. Smaller factories are not governed by the bylaw. As a result, there
is no vegetation cover in the parts of the project area occupied by small factories.
To fill the gaps in the ecological network, we proposed a planting plan for a small factory. Our
goal was to illustrate how planning could be done for one small area, then use this as a casestudy to guide future planting at other small factories. The goal would be to create "steppingstones" (i.e., ecological corridors) for overwintering birds.

RESULTSCALCULATION OF NDVI AND EXTRACTION OF VEGETATION COVERWe calculated an NDVI value for each grid cell (Figure 2) and found that the NDVI values
ranged from –1 to 1. The result of our ground-truthing showed that grid cells with an NDVI
value of 0.1 or more were covered by vegetation.
The results revealed that large woodlands and many of the small woodlots were located in a
mountainous area called the Rokko Mountains, in the northwestern part of the study area, andthat there was little vegetation cover in the project area. Figure 3 shows that there is no 200-m
buffer zone from over 2 ha woodland near from the project area, therefore it might be difficult
for forest birds to reach the first site scheduled for planting under the forest plan for the 21stcentury during the breeding season. However, 500-m buffer zones connect the Rokko
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T. Ichinose and W. Miyata / IUFRO 8.01.03 Landscape ecologyMountains and the project area along the Mukogawa River, thus forest birds can probably moveinto this area. However, a large gap was found in the northern part of the project area (Figure 3),
and this gap must be bridged to complete this ecological corridor.
PLANTING PLAN FOR A SMALL FACTORY
There was no large contiguous space available for planting at the small factory. We thus
selected four small areas for planting (Figure 4).
Our planting concept was to use native species whose seeds can be collected from theMukogawa River watershed, with an emphasis on tree species that produce berries and nuts thatcan serve as foods for birds during the winter season. In addition, we selected deciduous trees
for the entrance (Area 1) and evergreen trees for the northern end of the factory (Areas 3 and 4).
An illustration of the proposed planting for Area 2, which is beside a parking lot, is shown inFigure 5.
There are many volunteer groups interested in planting trees in Amagasaki City. Some havebeen growing large numbers of seedlings of native species for afforestation of the project site.
Thus, we are confident that we can secure enough native seedlings and volunteers tosuccessfully establish forest vegetation at the factory site.

REFERENCES
Hashimoto, H. and Natuhara, Y., 2002. Predicting the habitat of great tit (Parus major) in a largecity using a logistic regression model. Journal of the Japanese Institute of LandscapeArchitects, 65: 539-542. (in Japanese with English summary)
Ichinose, T., 2002. Relationship between the appearance of birds in urban parks and thevegetation and surrounding land uses: A basic study for ecological network planning inurban areas. City Planning Review, Special Issue 37: 919-924. (in Japanese with Englishsummary)
Ichinose, T. and Katoh, K., 1998. Factors influencing bird distribution among isolated woodlots
on a heterogeneous landscape in Saitama Pref., Japan. Ekologia (Bratislava), 17: 298-310.
Kowarik, I. and Körner, S. (Eds.), 2005. Wild urban woodlands. New York: Springer.

Patterns and processes in forest landscapes. Consequences of human management
R. Lafortezza and G. Sanesi (eds.) © 2006 Accademia Italiana di Scienze Forestali