Ecological and social evaluation of landscape in a rural area with terraced paddies in southwestern Japan

Landscape and Urban Planning 70 (2005) 301–313

Ecological and social evaluation of landscape in a rural area with terraced paddies in southwestern Japan Naoki Iiyama a,∗ , Mahito Kamada b,1 , Nobukazu Nakagoshi c,2 a

b

Echo Co. Ltd., 4-53 Minamisuehiro, Tokushima 770-0865, Japan Department of Civil Engineering, University of Tokushima, 2-1 Minamijyousanjima, Tokushima 770-8506, Japan c Graduate School for International Development and Cooperation, Hiroshima University, 1-5-1 Kagamiyama, Higashihiroshima, Hiroshima 739-8529, Japan

Abstract Since the 1960s, improving socio-economic conditions in rural Japan have led to the rise in man-made or man-shaped landscapes, which has in turn resulted in formerly abundant species becoming endangered. In order to conserve biodiversity in rural areas, former agricultural landscapes must be conserved. The problem is that ecologically appropriate landscapes are not always compatible with the needs of local residents or land owners. Prior to carrying out any particular conservation measures, regional landscape management must consider both ecological and social approaches and present acceptable approach-specific management goals in an open and transparent manner. This study, undertaken in the Ohaga district of southwestern Japan, a typical rural area with terraced paddy fields, sought to develop a framework for evaluating regional resources from a landscape ecology perspective. Monitoring the temporal change of landscape structures and vegetation revealed the presence of habitats, such as the pine forest and grasslands bordering the rice paddies, which harbour specific plant species or populations, some now endangered. From a social standpoint, questionnaires revealed that local inhabitants wanted landscape management options which would conserve the pine forest, paddy fields and levee grasslands. Local farmers thought that the landscape should be used and managed as a rural park, rather than for agricultural purposes. These desirable landscape element types can serve as targets for conservation, but ultimately a new system of agricultural management must be developed to sustain the rural landscape. © 2004 Elsevier B.V. All rights reserved. Keywords: Agricultural landscape; Evaluation and conservation of landscape; Rural planning; Terraced paddy

1. Introduction In Japan, as in many Asian nations, rice farming is one of the most important industries and greatly ∗ Corresponding author. Tel.: +81-88-625-6066; fax: +81-88-625-5950. E-mail addresses: [email protected] (N. Iiyama), [email protected] (M. Kamada), [email protected] (N. Nakagoshi). 1 Tel.: +81-88-656-9134; fax: +81-88-656-9134. 2 Tel.: +81-824-24-6511; fax: +81-824-24-6511.

0169-2046/$20.00 © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.landurbplan.2003.10.024

influences regional landscapes. Terraced paddies are a common agricultural landscape feature in mountainous areas of Japan. Traditional agricultural management practices have created and maintained specific ecosystems (Moonen and Marshall, 2001). The periodic felling of trees for firewood has resulted in a landscape comprised of secondary forest patches (Kamada et al., 1991; Kamada and Nakagoshi, 1997), while periodic grass-mowing for green manure has maintained grasslands and biodiversity (Naito and Nakagoshi, 1995; Okubo and Maenaka, 1995; Okubo,

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2002). Heterogeneous habitat patches resulting from differences in management practice among farmers has kept biodiversity high (Smeding and Joenjeb, 1999; Iiyama et al., 2002). However, the improvement of socio-economic conditions since the 1960s has had a drastic impact on rural landscapes. Many terraced paddies in mountainous regions have been abandoned due to the difficulties inherent in their cultivation and to the shortage of labourers resulting from younger individuals moving to urban areas to work (Yokohari et al., 1994). Landscape changes have resulted in terraced paddy landscapes becoming endangered, as have a number of species inhabiting these man-made ecosystems (Yamaguchi and Umemoto, 1996; Kadono, 1998; Asami et al., 2001). In order to conserve the biodiversity of rural regions, landscapes that were sustainable under agricultural management must be conserved. Given the present situation, a number of individuals and organisations in Japan have sought to conserve and restore terraced paddy landscapes and their biodiversity, and pushed for conservation legislation (Nakajima, 1996). The Japanese government has also begun to subsidize farmers to continue traditional agricultural management practices. However, one problem with such management is that ecologically sustainable landscapes are not always compatible with the needs of local residents or land owners (Stein and Anderson, 2002). Prior to carrying out any particular conservation measures, regional landscape management must consider both ecological and social approaches and present acceptable approach-specific management goals in an open and transparent manner. In this study, we propose a landscape evaluation protocol and examine its usefulness in a rural area with terraced paddies. This protocol would include (i) a method of ecological evaluation of rural landscapes, (ii) a method of social evaluation of rural landscapes through a questionnaire, and (iii) an evaluation of the landscape addressing both ecological and social concerns and a determination of the desired result (Fig. 1).

2. Study area The study area, the Ohaga district, located in Okayama Prefecture in southwestern Japan (34◦ 59 N, 133◦ 59 E), had an area of 3.53 km2 . The mean an-

Fig. 1. Flow chart of rural conservation planning.

nual air temperature and precipitation of the last 30 years are 12.8 ◦ C and 1493 mm, respectively (Chuo Town Office, 1988). The area was designated as the target area for a “landscape conservation project” by the Okayama Prefectural Government in 1992, owing to its large number of well maintained terraced paddies. The social situation, however, has changed and landscape conservation has become difficult (Fig. 2). According to statistical data collected by the Ministry of Agriculture, Forestry and Fisheries, the number of farm households in the area decreased from 73 in 1970 to 53 in 1995 (Fig. 2(1)). The number of farm households managing small fields (<0.5 ha) had declined from year by year (Fig. 2(2)), whereas numbers of those managing large paddies (>2 ha) had remained relatively stable (Fig. 2(3)). The number of farmers decreased from 250 in 1970 to 150 in 1995, and the number of labourers over 65 years old increased from year to year (Fig. 2(4) and (5)). The number of tractors in the region increased to current numbers of over 100 (Fig. 2(6)). Labour cattle were raised for agricultural work until the 1970s, but are no longer present due to the widespread advent of tractors. The area of paddies decreased from year to year, while the area of upland fields remained constant (Fig. 2(7) and (8)). In addition to labour shortages, the decrease in paddy area was attributable to the national policy of reducing the rice crop. Some of the areas previously cultivated as paddies had been transformed into upland fields (Iiyama et al., 1999). The area of grasslands decreased from 7.5 ha in 1970 to only 1 ha in 1995 (Fig. 2(9)). The grassland was

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Fig. 2. Socio-economic change of Ohaga district. (1) Number of farm houses, (2) farm houses of <0.5 ha, (3) farm houses of >2 ha, (4) agricultural workers, (5) employment rate of individuals 65 or more years old, (6) tractors, (7) total area of paddies, (8) total area of upland fields and (9) total area of grasslands.

originally kept as a supply of feed for labour cattle and green fertilizer for cropland.

3. Methods 3.1. Ecological aspects of landscape evaluation Field surveys carried out in 1996 identified the region’s landscape element types (LET), in terms of plant communities and land use types. A survey of vegetation was also conducted for each LET according to the Braun-Blanqute (1964), and plant species characteristics of individual LETs were extracted through a table operation method (Mulloer-Dombois and Ellemberg, 1974). Quadrat size was 10 m × 10 m for forested LETs, and 2 m × 2 m for grassland types. The 1996 vegetation map was generated with the aid of aerial photographs taken in 1995 and 1996 by the Geographical Survey Institute of Japan. In order to assess temporal changes in landscape structure, a vegetation map was generated for 1964, using aerial photographs taken in that year. As drastic changes in rural landscapes and social systems only began in the 1960s (Kamada et al., 1991), in 1964, traditional rural landscapes would have still been prevalent (Iiyama et al., 1999). Therefore, in order to find identify the LETs to be targeted for conservation, the 1964 and 1996 landscapes were compared. The size of each patch of vegetation was measured for both years, and the changing pattern of each LET documented.

Among LETs occurring in the region, grassland maintained at paddy levees was selected as one of the conservation targets. Consequently, in order to estimate necessary management efforts and to develop a conservation plan, the annual frequency of grass-mowing was determined through interviews with farmers. The time necessary to mow an entire grassland area was also ascertained through observations and experimental work by the authors. 3.2. Social aspects for landscape evaluation In order to understand the recognition and evaluation of landscape change by local farmers, questionnaires were distributed directly to all 75 households and their answers collected from November 1995 to March 1996, with 44 (59%) of households responding. The proportion of the household types was as follows: (i) part-time farm households with over 50% of income being obtained from agricultural work (46%) and (ii) part-time farm households with less than 50% of income being obtained from agricultural work (33%). Households not engaged in any form of agriculture accounted for 12% of households. Sixty-three percent of the respondents had lived in the region their whole lives, whereas the remainder had moved from other districts. The questions, provided with a five-step responserange ranging from “affirmative” to “negative”, sought to assess respondents’ evaluation of the present landscape, as well as their opinions on favourable land use

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in the future. Questions also addressed were whether respondents recognized changes in the distribution of plants and animals. 3.3. Estimation of management efforts to maintain grassland Among LETs occurring in the area, grasslands maintained at paddy levees were selected as one of the primary conservation targets. In order to assess the level of effort expended in managing grasslands and devise a conservation plan, annual frequency of grass-mowing was confirmed by interviews with farmers. The time required to mow grass was also ascertained through observations and experimental work by the authors. 4. Results 4.1. Landscape structure and its temporal change The changing pattern of each LET from 1964 to 1996 is summarized in Fig. 3. Mature Chamaecyparis obtusa (Hinoki cypress) plantations, mature non-deciduous broad leaf forests, bamboo plantations and inhabited area have all increased over the 32 years studied. Conversely, the area of middle-aged and recent plantations of C. obtusa, pine forests of all maturity classes, young deciduous broad leaf forests, grasslands, upland fields, and paddies have decreased. By 1996 mature C. obtusa plantations had become dominant through their replacement of other vegetation. Over 90% of the area of middle-aged and recent C. obtusa plantations, young deciduous broad leaf forests and grasslands, and 65% of mature deciduous broad leaf forests present in 1964 had become mature C. obtusa plantations by 1996. As C. obtusa is an introduced species planted for timber production, the habitat of native plant species has decreased. The increase in non-deciduous broad leaf forest was largely the result of the loss of pine forests as a result of pine-wilt disease. In former pine forests, decimated by the disease, non-deciduous broad leaf trees grew up as part of the succession, quickly replacing the pine with non-deciduous broad-leaved forests (Kamada and Nakagoshi, 1996). Bamboo plantations had been managed to obtain poles for drying the harvested rice. However, such

Fig. 3. Changing pattern of each landscape element type. The boxes show area of each element (ha). Bold lines show changed ratio >90%, from 1964 to 1996. Legend numbers mean: 1: C. obtusa mature forest; 2: C. obtusa middle-aged forest; 3: C. obtusa young forest; 4: Pinus densiflora mature forest; 5: P. densiflora middle-aged forest; 6: deciduous broad leaf mature forest; 7: deciduous broad leaf middle-aged forest; 8: non-deciduous broad leaf mature forest; 9: grassland; 10: bamboo plantation; 11: upland field; 12: terraced paddy; 13: inhabited area.

bamboo poles became useless with the spread of combine harvesters. Bamboo rhizomes are highly invasive of neighbouring plant communities, such that under unmanaged conditions bamboo can greatly expands its area (Isagi and Torii, 1997). Species groups that characterize the forest LETs are presented in Table 1. For the LETs for which the area has increased over the past 32 years, six characteristic species were found. Two species commonly grew in both broad leaf and pine forests, and four characteristic species were also found in the C. obtusa plantations. For the LETs which had declined in area, 28 characteristic species were found: 13 from deciduous broad leaf forests, 2 from pine forests, and 13 species commonly found in both forest types. In terms of mean number of species, C. obtusa plantations had 16 and non-deciduous broad leaf forest 18. Some 20 species

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Table 1 Species groups that characterize the landscape element types among forests Increased Land use type

Decreased

Average of the number of species Sample number

Chamaecyparis obtusa plantation 16 4

Dioscorea japonica Rubus hirsutus Rhus javanica Agrostis alba

1 1 1 1

Quercus myrsinaefolia Symplocos lucida Ilex serrata Osmunda japonica Carpinus tschonoskii Carex lanceolata Hydrangea luteo-venosa Albizia julibrissin Cyrtomium fortunei Clematis apiifolia Trachycarpus fortunei Kadsura japonica Alnus firma Phyllostachys nigra var. henonis Cymbidium goeringii Cirsium japonicum Rubus hakonensis

1+ 1+ – – – – – – – – – – – – – – –

1+ 2+ – – – – – – – – – – – – – – –

– – I+ I+ II ± 4 II + II ± 1 I2 I+ I+ I1 I1 II1 – 4 I+ II + – –

– – – – – – – – – – – – – – – 1+ 11

Gleichenia japonica Cinnamomum japonicum Asplenium incisum Illicium religiosum Magnolia salicifolia Akebia quinata Ligustrum tschonoskii Nandina domestica Osmanthus heterophyllus Rhododendron reticulatum Prunus jamasakura Neolitsea sericea Quercus serrata

– – – – – – – – – – – – –

– – – – – – – – – – – – –

I+ I+ I+ I±1 I+ I+ II ± 1 I+ I±1 II ± 1 II ± 3 III ± 1 IV1–5

1+ 1+ 1+ 1+ 1+ 2+ 11 1+ 2+ 1+ 1+ 2±1 22

Eurya japonica Ilex crenata Rosa multiflora Struthiopteris niponica Ardisia japonica Lyonia ovalifolia var. elliptica Smilax china Camellia japonica Viburnum erosum Ilex pedunculosa Clethra barbinervis Rhus trichocarpa Castanea crenata Miscanthus sinensis Oplismenus undulatifolius var. japonicus

3+ 1+ 2+ 2+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 12 2+ 2+

21 1+ 1+ 1+ 2+ 2±1 1+ 2±1 1+ 21 11 1+ – – –

IV ± 2 IV ± 2 II + III + III ± 2 III ± 2 II + II + I+ IV ± 3 II ± 2 I2 II1 – 2 I1 –2 I+

2±1 2+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 11 1+ 1+ 11 1+ 1+

+ + + +

Non-deciduous broadleaf forest 18 2

Deciduous broadleaf forest 20 15

Pine forest

– – – –

– – – –

– – – –

24 3

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Table 1 (Continued ) Increased Land use type

Decreased Non-deciduous broadleaf forest 18 2

Deciduous broadleaf forest 20 15

Pine forest

Average of the number of species Sample number

Chamaecyparis obtusa plantation 16 4

Trachelospermum asiaticum var. intermedium Arundinario pygmaeae Akebia trifoliata Quercus variabilis Ophiopogon japonicus Elaeagnus pungens Pinus densiflora Pteridium aquilinum var. latiusculum Hedera rhombea Zelkova serrata Acanthopanax sciadophylloides Quercus glauca Aucuba japonica Ligustrum japonicum Rhododendron kaempferi Chamaecyparis obtusa Wisteria floribunda Rubus parvifolius Lindera umbellata Rubus palmatus Cryptomeria japonica Hydrocotyle maritima Artemisia princeps Paederia scandens var. mairei Tripterospermum japonicum Zanthoxylum schinifolium Pieris japonica Dendropanax trifidus Dicranopteris dichotoma

1+ 33 − 5 1+ 1+ 2+ 3+ 1+ 1+ 1+ 1+ – – – – 1+ 43 − 5 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ 1+ – 1+ – –

– – – – – – – – – – 11 23 − 4 21 11 – – – – – – – – – – – 1+ 2±1 1+ 21 − 2

I+ V±5 III + IV1–5 III ± 2 II ± 2 II ± 1 II + I±1 I1 III ± 3 II ± 2 II ± 2 II + IV ± 2 I+ II ± 1 I+ I±3 I+ I±1 I+ 11 I+ I+ I±2 – – –

1+ 22 − 5 2+ 1+ 1+ 1+ 33 − 5 11 2+ 1+ 2+ 11 2±2 1+ – – – – – – – – – – – – 31 1+ 3+

24 3

Eliminating species appearing only once. a Land use type (average of the number of species) [sample number].

occurred in deciduous broad leaf forest and 24 species in pine forest. This suggests that the number of species has declined in accordance with the expanding areas of C. obtusa plantations and non-deciduous broad leaf forest. In order to conserve the plant diversity, deciduous broad leaf forest and pine forest must be conserved. Paddy levee grassland species were grouped with respect to mowing frequency as confirmed through interviews with farmers (Table 2). A mean of 21 and 23 species, respectively, were associated with grasslands mown on average 2 (Type III) and 3.4 (Type II) times a year. Type I grasslands, mown

four to eight times a year, averaged only 10 species, while the unmown Type IV grasslands averaged only 7 species. At a lower mowing frequency, the coverage of Eulalia (Miscanthus sinensis), a tall grass, increased, entirely covering the ground in Type IV grasslands. In Type IV grasslands, climbing plants Pueraria lobata and Paederia scandens var. mairei grew on the Eulalia. 4.2. Evaluation of regional resources by local residents Replies to questions related to land use are summarized in Fig. 4. Regarding the desirability of land

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Table 2 Species groups in the grassland occurring on paddy levees Grassland type Mean number of mowings Mean percent cover by M. sinensis Mean number of species Number of stands

I 6.0 5.5% 10 7

II 3.4 3.1% 21 7

III 2.0 23.6% 23 6

IV 0.4 87.5% 7 6

Miscanthus sinensis Poa annua Trisetum bifidum Glechoma hederacea Lolium multiflorum Paspalum distichum Cynodon dactylon Eclipta prostrata Salvia japonica Youngia denticulata Patrinia scabiosaefolia Ophiopogon japonicus Akebia trifoliata Pennisetum alopecuroides Kalimeris yomena

II ± 3 II + II + – – – – – – – – – – – –

IV ± 1 – – III ± 1 III ± 1 II + II1 II + II + II + – – – – –

V±4 – – – – – – – – – III + III + II + II ± 1 II +

V5 – – – – – – – – – – – – – –

Potentilla kleiniana Oxalis corniculata Cyperus microiria Fimbristylis miliacea Arthraxon hispidus Phleum pratense Pteridium aquilinum var. latiusculum Lindernia procumbens Ranunculus silerifolius Viola grypoceras Bidens tripartita Clematis apiifolia Arundinella hirta Cyperus brevifolius var. leiolepis Lapsana humilis Pueraria lobata Pueraria scandens var. mairei Artemisia princeps Arundinario pygmaeae

– – – – – – – – – – – – – – – – – IV ± 3 IV ± 3

III + II + III + II + III ± 2 II ± 1 II + I+ I+ I+ I+ I+ I+ I+ I+

I+ II + I+ II + I+ I+ I+ I2 I1 I+ I+ I+ I1 I+ I1 –

V±1 V±3

V±1 V±3

– – – – – – – – – – – – – – – I+ V+ V±1 IV ± 1

Eliminating species appearance only once and other non significant species. a Grassland type (mean number of mowings, mean percent cover by M. sinensis, mean number of species, number of stands)

use types, 36% of respondents wrote that agriculture would be the most desirable land use in the future, while another 26% wished the landscape to be used as a nature-park. The total percentage responding with either “nature-park”, “place for leisure” or “tourist resort” was 39%, greater than that of those who responded “agriculture”. Regarding people’s image of the present landscape, 57% of respondents thought it to be beautiful, and 51%

thought that it should be conserved. Ninety percent of respondents knew that the Ohaga district had been designated as a target area for landscape conservation by the prefectural government. Half of the respondents thought that the biodiversity should be conserved. Motivations for continued cultivation are presented in Fig. 5. As rice cultivation was only necessary for self-sufficiency, not for economic benefit, the most important reason stated for continuing to exploit the

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Fig. 4. Residents opinions related to land use.

rice paddies was that the farmers thought they had an obligation to keep paddies and pass them on to their children, the paddies having been passed on to them by their ancestors. Few farmers were serious about growing rice for consumer supply. Thus, most farmers are not willing to continue agricultural work as a business. Local residents apparently wish to keep the

agricultural landscape not for its economic potential, but for other purposes, such as tourism. LETs favoured by residents are presented in Fig. 6. Japanese-style homes, newly paved roads, irrigation canals, cedar plantations and managed pine forest were the favoured LETs. On the other hand, LETs looked upon unfavourably by residents included

Table 3 Recognition by residents on the change of plants present Frequency of seeing Often seen Increasing Stable

Decreasing Unaware

Miscanthus sinensis, Pueraria lobata, Plantago asiatica Taraxacum japonicum, Imperata cylindrica var. koenigii, Trifolium repens

Usually seen

Rarely seen

Lycoris radiata, Pulsatilla cernua, Patrinia scabiosaefolia, Solidago altissima, Gentiana scabra var. buergeri Swetria japonica

Artemisia princeps, Cirsium spp. Rumex japonicus, Pteridium aquilinum var. latiusculum, Equisetum arvense, Campanula punctata, Rubus crataegifolius

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Fig. 5. Residents response to “the motivation of continuing agriculture”.

abandoned terraced paddies, old terraced paddies, abandoned cars, refuse, abandoned construction materials, vacant homes, western style homes, bamboo plantations and unmanaged pine forest. The residents’ recognition of changes in flora is summarized in Table 3. M. sinensis, P. lobata and Plantago asiatica were recognized as plants that were increasing their coverage in the area. Residents were also aware that the numbers of Swertia japonica had decreased. These changes were caused by the cessation of cultivation and levee management, but farmers favoured a managed levee type though which S. japonica could be sustained (Fig. 6). In order to keep levees in a favourable condition, farmers were thinking that mowing three to four times a year was necessary. Experimental mowing conducted by the authors established the time necessary for a single person to mow around a 0.1 ha paddy at 52 min. The area of cultivated rice paddies

in the Ohaga district in 1995 was about 40 ha, thus 347 person hours would be required to manage the entire area of levees surrounding the paddies. If mowing was done three times a year, 1041 person hours would be required in total.

5. Discussion 5.1. Selecting conservation targets In the process of ecological planning for the conservation of rural landscapes, conflicts frequently arise between planners/ecologists and local residents, particularly because the two parties generally do not share the same target image for conservation (Haaren, 2002; Stein and Anderson, 2002). Therefore, a both socially and ecologically acceptable landscape image should be generated (Fig. 7).

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Fig. 6. Responses for desirable landscape elements.

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Fig. 7. Balanced conservation planning for rural landscape.

From the landscape and vegetation structure surveys, it is clear that significant species losses occurred in the study area between 1964 and 1996, due to a decline in the areas of pine and deciduous broad leaf forests. Over this period, abandoned pine forests were replaced by non-deciduous broad leaf forest which was only able to support a fraction of the species formerly supported by pine forest. Therefore, from an ecological perspective, pine and deciduous broad leaf forests should be selected as a conservation target. Managed pine forest was evaluated as a favourable landscape by local residents, while abandoned pine forest met with disfavour. Setting the pine forest as a conservation target is, therefore, acceptable and advantageous both ecologically and socially. It is well known that M. sinensis and P. lobata, species recognized by farmers as having increased in coverage, come to dominate abandoned grasslands (Ohkuro et al., 1996). These facts were confirmed by our vegetation survey, which showed that coverage by M. sinensis increased with decreased mowing frequency, and that P. lobata appeared at paddy levees where mowing had been abandoned. From an ecological perspective, the increase in coverage by these species caused a decrease of species number, threatening plant species that are only maintained in grassland by regular mowing (Naito and Nakagoshi, 1993; Okubo, 2002). For example, S. japonica, which was recognized by farmers as a species decreasing in number, has been threatened due to habitat loss caused by the cessation of grass-mowing (Naito and Nakagoshi,

1993; Manabe et al., 1997). We were unable to find any plants of this species in our vegetation survey. Thus, it is necessary to continue mowing at levees in order to conserve species diversity (Kobayashi et al., 1998; Iiyama et al., 2002). Residents were against the abandonment of paddy levee landscapes to a dense cover of M. sinensis and/or P. lobata. Biodiversity has forced to be decreased at paddy levee dominated of M. sinensis and/or P. lobata. It would therefore be easy for both residents and ecologists/planners to accept to set paddy levees as a conservation target as well as pine forests. Before making an actual activity to conserve/restore the levee, setting S. japonica as a flagship species (Noss, 1990) and putting a catchphrase “recovering S. japonica on paddy levee” might be helpful to give residents concrete image of the conservation goal, as residents can easily visualize the habitat type of S. japonica. 5.2. A concept for maintaining rural landscape The terraced paddy levee landscape and pine forest have been maintained under human management. However, the number of agricultural labourers has decreased and farmers are only willing to maintain the landscape for parks or tourism rather than agricultural purposes (Figs. 4 and 5). In this situation, a new management system has to be established to maintain the landscape. Here, the most serious problem is how to secure labour for such tasks as mowing. The use of a volun-

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teer work-force to maintain the landscape has some promise (Takahashi, 2002). Many people, particularly city-dwellers, are willing to go to rural areas during their holidays and to do agricultural and/or restoration work as volunteers. There are over 500 civic groups devoted to restoring rural landscapes in Japan (Nakagawa, 2001). By responding to the demands of city people, labourers for the management of rural landscapes can be secured (Yamauchi and Takahashi, 2002). Conflicts may occur when rural residents resent the presence of outsiders, or are unwilling to use landscapes for strictly agricultural pursuits. However, in the case of the study area in question, many residents have accepted opening the region to tourism, and it is easy to negotiate a consensus between local and city residents with regard to their image of conservation targets. In order to make actual plans for conservation projects to be undertaken with the assistance of volunteers, the number of required labourers should be estimated. For example, to mow all grasslands located at levee sites, it is estimated, based on field observations, that 347 person hours would be required. Given that a volunteer could be expected to work 8 h during one weekend (4 h per day), about 43 volunteers would be required to mow all the grasslands. Such a number is believed to be realistically attainable.

6. Conclusion In order to ascertain the target image for conservation of rural landscape, the method described in this paper is useful because planners can rationally balance the ecological necessity of conservation and social acceptability of conserving the targets. In the case of the area studied, ecological demands for conservation seem to be compatible with social requirements, so one can move to the next step of drawing up actual conservation plans. To develop such plans, a workshop should be held with the planners, local residents and local town officers. To implement the plans developed, the usefulness of running a workshop under the PCM (Project Cycle Management) method has been confirmed (Yamanaka et al., 2000).

Acknowledgements We would like to thank all people of Ohaga district and staff of Chuo Town Office for their willing cooperation. Partial funding was supplied by the JSPS Grants-in-Aid for Scientific Research (no. 14380276).

References Asami, K., Nakao, M., Akamatsu, H., Tamura, K., 2001. A case study of vegetation management of abandoned rice fields for the conservation of water and wetland wildlife. J. Jpn. Inst. Landsc. Arch. 64, 571–576 (in Japanese). Braun-Blanqute, J., 1964. Pflanzensoziologie, Grundzüge der Vegetationskunde, 3 Aufl, Springer, Wien. Chuo town office, 1988. The Plan of Forestry Construction. Chuo Town Office, Okayama (in Japanese). Haaren, C.V., 2002. Landscape planning facing the challenge of the development of cultural landscapes. Landsc. Urban Plan. 60, 73–80. Iiyama, N., Nehira, K., Nakagoshi, N., 1999. Landscape change of terraced paddies in rural Japan. Acta Universitatis Carolinae Environmentalica 13, 69–76. Iiyama, N., Kamada, M., Nakagoshi, N., 2002. The effect of boundary ridge structures and grass-cutting on plant communities around terraced paddy field. J. Jpn. Inst. Landsc. Arch. 65, 579–584 (in Japanese with English abstract). Isagi, Y., Torii, A., 1997. Range expansion and its mechanism in a naturalized bamboo species, Phyllostachys pubescens, in Japan. J. Sustain. For. 6, 127–142. Kadono, Y., 1998. Diversity of the flora of Naka-ikemi, a lowland wetland in Tsuruga, Fukui Prefecture, and significance of its conservation. Jpn. J. Ecol. 48, 163–166 (in Japanese with English abstract). Kamada, M., Nakagoshi, N., 1996. Landscape structure and the disturbance regime at three rural regions in Hiroshima prefecture, Japan. Landsc. Ecol. 11, 15–25. Kamada, M., Nakagoshi, N., 1997. Influence of cultural factors on landscape of mountainous farm villages in western Japan. Landsc. Urban Plan. 37, 85–90. Kamada, M., Nakagoshi, N., Nehira, K., 1991. Pine forest ecology and landscape management: a comparative study in Japan and Korea. In: Nakagoshi, N., Golly, F.B. (Eds.), Coniferous Forest Ecology from an International Perspective. SPB Academic Publishing, The Hague, pp. 43–62. Kobayashi, T., Hori, Y., Nomoto, N., 1998. Effects of mowing on the species diversity in relation to the dominance of dwarf-bamboo Pleioblastus chino Makino in a semi-natural grassland. Grassl. Sci. 44, 173–176. Manabe, T., Naito, K., Nakagoshi, N., 1997. Vegetation structure of a secondary grassland at a line corridor in fukuchi Mountain system, northern Kyushu. Bull. Kitakyushu Museum Nat. Hist. 16, 113–135.

N. Iiyama et al. / Landscape and Urban Planning 70 (2005) 301–313 Moonen, A.C., Marshall, E.J.P., 2001. The influence of sown margin strip, management and boundary structure on herbaceous field margin vegetation in two neighboring farms in southern England. Agric. Ecosyst. Environ. 86, 187–202. Mulloer-Dombois, D., Ellemberg, H., 1974. Aims and Methods of Vegetation Ecology. Wiley, New York. Naito, K., Nakagoshi, N., 1993. Flora and vegetation in a protected area for Iris rossi Baker (Iridaceae), a threatened plant in Hohu city, Yamaguchi prefecture. Mem. Fac. Integr. Art. Sci., Hiroshima Univ. Ser. IV 19, 19–37. Naito, K., Nakagoshi, N., 1995. The conservation ecology of Iris rossi baker (Iridaceae), a threatened plant in rural Japan. J. Plant Res. 108, 477–482. Nakagawa, S., 2001. Partnership for conserving rural forest in Japan. In: Takeuchi, K., Washitani, I., Tsunekawa, A. (Eds.), The Traditional Rural Landscape of Japan. University of Tokyo Press, Tokyo, pp. 124–135 (in Japanese). Nakajima, M., 1996. Sustainability of Rice Terraces. J. Geogr. 105, 547–568 (in Japanese). Noss, R.F., 1990. Indicators for monitoring biodiversity: a hierarchical approach. Conserv. Biol. 4, 355–364. Ohkuro, T., Matsuo, K., Nemoto, M., 1996. Vegetation dynamics of abandoned paddy fields and their levee slopes in mountainous regions of central Japan. Jpn. J. Ecol. 46, 245–256 (in Japanese with English abstract). Okubo, K., 2002. The present state in the study of biological diversity on semi-natural grassland in Japan. Grassl. Sci. 48, 268–276 (in Japanese). Okubo, K., Maenaka, H., 1995. Effect of consolidation on paddy-side grassland communities and ecological niche in agro-ecosystem. J. Jpn. Inst. Landsc. Arc. 58, 109–112 (in Japanese). Smeding, F.W., Joenjeb, W., 1999. Farm-nature plan: landscape ecology based farm planning. Landsc. Urban Plan. 46, 109–115. Stein, T.V., Anderson, D.H., 2002. Combining benefits-based management with ecosystem management for landscape planning: Leech Lake watershed, Minnesota. Landsc. Urban Plan. 60, 151–161. Takahashi, Y., 2002. Activities of biodiversity conservation on semi-natural grassland in Japan. B. Introduction for the special feature. Grassl. Sci. 48, 264–267 (in Japanese).

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Yamaguchi, H., Umemoto, S., 1996. Classification of paddy levees in terms of plant resource complex. J. Weed Sci. Soc. Jpn. 41, 286–294 (in Japanese). Yamanaka, H., Sawada, T., Kozuki, Y., Kamada, M., Ishida, K., Yamaguchi, Y., Tanaka, Y., 2000. An analysis of rice-terrace conservation strategy based on the Project-Cycle-Management method. Environ. Syst. Res. 28, 255–266 (in Japanese with English abstract). Yamauchi, K., Takahashi, Y., 2002. Citizens’ participation in conservation activities of Aso grassland. Grassl. Sci. 48, 290– 298 (in Japanese). Yokohari, M., Brown, R.D., Takeuchi, K., 1994. A framework for the conservation of rural ecological landscapes in the urban fringe area in Japan. Landsc. Urban Plan. 29, 103–116. Naoki Iiyama is working at Echo Co., Ltd. His major works and interests are in ecological assessment, mitigation, restoration and planning, and he advises the local government on ecologically adequate method for reducing environment impact in civil engineering works. His dream is to achieve the conservation/restoration of rural ecosystems under the cooperation with local people. This study made a chapter of his doctoral dissertation at Hiroshima University.

Mahito Kamada is an associate professor of Department of Civil Engineering, the University of Tokushima. His academic background is based on vegetation ecology and landscape ecology. His main interest is to reveal interactive process of landscape/vegetation change and human attitudes on land-use, in order to develop an ecologically adequate way for restoration.

Nobukazu Nakagoshi is a professor of Department of International Development and Cooperation, Hiroshima University. He is also working as a president of Japanese Branch of International Association for Landscape Ecology (IALE), and will work as a Vice president of IALE from 2004 to 2008. He has made efforts to introduce the concept of landscape ecology to Japan and to develop it to be matched with Japanese manner.