Biological diversity is an essential part of those foundations that we rely on. The diversity of life on earth provides essential “ecosystem services”; these were a key concept to evaluate the healthy functioning of ecosystems in the Millennium Ecosystem Assessment. Ecosystem services stand for all benefits that human societies receive from both unmanaged “natural” ecosystems and managed “cultural” ecosystems. Research in this field has increased considerably over the past years, and first attempts to express the value of ecosystem services in monetary terms have pointed at the fact that wetlands are among those ecosystems that have the highest value for human societies.

　The debate on sustainability and biological diversity has developed because our lifestyles often do not meet the basic requirement as it is laid out in the Convention on Biological Diversity: we are not using biological diversity “in a way and at a rate that does not lead to its irreversible decline, thereby maintaining its potential to meet the needs and aspirations of present and future generations.” Indeed we have lost over the past decades much of the diversity that was there until fairly recently – in the case of certain wetland ecosystems, losses are estimated at 70% to 99% e.g. in Japan and Central Europe.

　Consensus is growing that it is not enough to try to protect small remnants of ecosystems in reserves, but that we need to provide additional space to restore them to a favourable, healthy state. This will increase their resilience to cope with further environmental change and give them the evolutionary capability to develop dynamically through time. The management of degraded ecosystems and the creation of conditions that allow the development of certain ecosystem types in areas from which they have disappeared are commonly called “ecological restoration” or “nature restoration.” These activities are the main topic of this special issue of “Global Environmental Research.”

　Most articles focus on wetlands. This is due to several reasons: 1) wetlands are extremely important habitats for a large number of organisms; 2) they are essential for human well-being via vital ecological services; 3) they have been altered severely by human activities; 4) numerous research projects are being undertaken to understand how they function, and 5) a significant number of restoration projects are underway to counter the enormous losses that have occurred.

　Nature conservation and restoration are based on values that are not necessarily shared by all stakeholders, and therefore it is essential to include the socio-economic background in any discussion of scientific approaches to the topic. Originally it had been intended to collect contributions in particular from Japan and Europe; parallels in socio-economic conditions between these regions let it seem likely that comparing the respective approaches would be interesting for readers of various backgrounds. However, we were able to also include articles that cover further regions in southern, eastern and South-East Asia, thus widening the geographical scope considerably. As a consequence, the topics of the articles have become more diverse, and not all relevant aspects could be covered for all geographical regions. The contributions range from general overviews and papers on philosophical or historical aspects to the results of field studies on vegetation succession and habitat use by birds. We hope that readers with an interest in ecological as well as policy-related aspects of nature restoration will find useful information in this issue. If its publication helps to stimulate further research and to support the practice of biodiversity conservation and restoration, its purpose would be fulfilled.

　Through the post-war economic miracle, Japan has experienced exceptional growth and remarkable improvement in its living standards. During this period of rapid economic growth, a short time in the eyes of the long history of the country, Japan’s nature, which was once diverse and rich, has been significantly transformed. Sandy beaches and tidal lands have been lost, coastal reclamation has steered people away from the sea, riverbanks and irrigation ditches have been reinforced with concrete and even the once abundant and familiar medaka, Japanese rice-fish, are now endangered. The Japanese, who once felt the changing seasons of nature now recognize them only by looking at the calendar. The idea of society co-existing with nature was advocated by Prime Minister Koizumi, the first prime minister of 21st century of Japan, in his policy speech. This idea prompted a movement for nature restoration and bore fruit in the Law for the Promotion of Nature Restoration. The freshness or innovative visions of this law can be seen in its purpose of restoring natural ecosystems that have been lost, its bottom-up system that allows local councils make decisions on planning, and its prerequisite of adaptive management that supports project implementation with learn-by-doing methods. Since the law is innovative, it possesses some discrepancies which might cause difficulties in its implementation. Possible difficulties may occur in:

– setting simple objectives, because natural restoration addresses the layered structure of time frame and spatial scale,

– focusing on ecosystems which are complicated and sensitive when conducting a specific project, and

– building a consensus by reconciling different values or opinions through open discussions of a committee.

　On the other hand, some advantages have been demonstrated convincingly through projects conducted over the last five years after the law came into effect. They include:

– A committee system which is effective at dealing with the layered structure of time frame and spatial scale.

– A stepwise approach which is reasonable for setting and achieving objectives.

– A learn-by-doing method which helps to develop technologies for nature restoration.

　This paper examines the difficulties and advantages mentioned above by clarifying the concept of nature restoration, giving a background/overview of the law and analyzing the case of the Kushiro Wetland.

　Restoration ecology has been accused of “faking nature,” meaning it pretends that natural systems can be replaced by artificial ones with equal value. The argument is flawed in that it assumes that the reference state for restoration projects is always pristine nature. Mostly, however restoration tries to improve degraded systems and the reference states are formed by human interaction with the environment. Restoration ecology operates on a different scale than other disciplines in ecology as it necessarily involves judgement about the value of nature, and here lies its benefit for conservation.

　The aim of this paper is to discuss the difference between nature conservation and nature restoration as well as the possibility of Environmental research with citizen participation.

　Compared with nature conservation, nature restoration has an expanded domain, techniques, and strategy. These differences make the process of social consensus building more complicated. The technique of adaptive management tries to address this problem and to introduce a method to enhance collaboration between science and local knowledge.

　However, when we consider the pluralistic and fluid character of the values that are prevalent in society, it appears necessary to pay more attention to the dynamism of values between man and nature. In order to find this “human-nature relation,” Japanese citizens have started participating in projects which collect not only biological and ecological data, but also sociological information. Some of these data are used for consensus building for nature conservation and restoration, tourism, the compilation of hazard maps and various other local activities.

　Thus participatory research explores in-depth the local characteristics of the “human-nature relation,” based on a renewed need for knowledge. Therefore, it could be argued that the movement of nature restoration links the renewal of ecosystems and the renewal of communities.

　Biological diversity, its evolution and functions are a matter of debate in scientific as well as political contexts. The variability of biological units can be studied across a range of spatial and temporal scales, e.g. from individuals to populations, communities and whole ecosystems, and their dynamics can be followed over “ecological,” “evolutionary” or “geological” time periods. Knowledge gained from studies at any of these levels of complexity can be relevant for decision-making in nature conservation or restoration, although actual projects often rely solely on data related to abundance and distribution of selected taxa collected during short-term surveys. In this paper it is demonstrated how insights concerning organismic and environmental variability on different spatial and temporal scales can be combined to develop a comprehensive framework for conservation and restoration of ecosystems, using wetlands in Japan and Europe as an example.

　In Japan, like other developed nations, restoration of floodplain wetlands has recently become an important social and scientific issue, after drastic reduction in area and ecological integrity. In an economical evaluation of global ecosystem services, lowland wetland or floodplain ecosystem types are most highly valued among the ecosystem types evaluated. Floodplain ecosystems, which are characterized by both spatial heterogeneity and temporal variability due to seasonal and unpredictable floods and traditional human interventions, i.e., plant resource collection causing also intermediate disturbances, can be regarded as shifting mosaics consisting of a variety of aquatic and non-aquatic habitats. The system of paddy fields interconnected not only to each other, but also to irrigation ponds and rivers by extensive canal networks is the commonest wetland type in Japan, and have provided substituting habitats for a large variety of wetland species after the loss of natural floodplain by development. However, recently-introduced intensive farming with heavy application of chemicals and seasonal drying of paddies after the rice harvest has caused rapid loss of biodiversity from agricultural landscapes. One promising measure to recover biodiversity, which has become practiced in a certain leading areas is winter flooding, i.e., continuous wetting of paddies during winter in combination with no or much reduced chemical applications compared to conventional modern farming.

　Over the past century, Japan’s wetlands have been greatly impoverished, and 61% completely lost. Miyagi Prefecture, in particular, lost 92%, most of which were converted to rice paddies. Ibaraki, Chiba and other prefectures have similar histories. Better productivity and efficiency have further fueled construction of paddies so as to eliminate their remaining wetland value by keeping them dry in winter, particularly on Japan’s drier Pacific coast. This has seriously impacted many wetland-dependent species, driving some close to extinction. This paper takes a 100-year perspective in discussing enhancement of rice paddies’ value as wetlands as a way of restoring wetland environments and sustainable local communities. It presents the case of the Ramsar site, “Kabukuri-numa and the surrounding rice paddies,” where co-existence of rice agriculture with over-wintering geese is being sought through restoration of some paddies back to wetland and winter-flooding of others still under cultivation.

　A proposal to dredge the Kabukuri-numa wetland became an opportunity for stakeholders to initiate a movement towards wetland protection and co-existence of wildlife with agriculture. Landholders agreed to re-convert of 50 hectares (ha) of paddy fields back to wetlands in 1998. The number of geese using Kabukuri- numa as a roosting site increased, illustrating that the restoration augmented the site’s wildlife carrying capacity. Farmers and others cooperated to implement a winter-flooding regime for nearby cultivated paddies. The project was examined from various standpoints, including as an application of the Ramsar Convention, and achievements and issues were identified.

　Normally, once a wetland is destroyed, restoration requires huge commitments of time and money, but restoration through the managing of rice paddies under cultivation as “agricultural wetlands” can be a realistic and effective method for restoring natural wetland environments in Asia.

　Land-use changes in Hyogo Prefecture from 1976 to 1997 were analyzed using Geographic Information Systems (GIS). Rice paddies in hilly and mountainous areas with a slope of 1:20 or greater were extracted to aid biodiversity conservation efforts in these areas. I focused on changes in the total length of the edge between rice paddies and forests because the edges are an attractive habitat for some amphibian species. I also extracted so-called “marginal” areas – areas in which at least 50% of the population is at least 65 years old – and “sub-marginal” areas – areas in which at least 50% of the population is at least 55 years old – to determine whether agriculture was sustainable in that area.

　The total area containing rice paddies decreased from 1971 to 1997, and there was no significant indication that abandoned fields changed into forest. The total edge length between rice paddies and forests decreased continuously over the same period. Almost half of the rice paddies were located in hilly and mountainous areas of Hyogo Prefecture, and much of these areas was classified as sub-marginal, raising the question of whether agriculture was sustainable in these areas. Finally, I considered three strategies for conserving aquatic habitats in hilly and mountainous areas.

　The Watarase Wetland is the largest lowland wetland (approximately 3,300 ha) remaining on the Honshu mainland of Japan, mainly composed of moist tall grasslands dominated by Phragmites australis (Cav.) Trin. ex Steud. and Miscanthus sacchariflorus (Maxim.) Benth., with the under-layer inhabited by more than 650 vascular plant species, including more than 50 threatened species listed in the national Red List. We analyzed the effectiveness of two sets of hyperspectral-remote sensing parameters ‘shoot density of each of P. australis and M. saccahriflorus’ and ‘summed shoot density and shoot density ratio of both species’ to map potential habitats of six threatened plant species. Analysis by generalized linear models (GLMs) showed that the parameters related to shoot densities of P. australis and M. sacchariflorus had significant effects on abundances of all species. Accuracy values evaluated by adj. R² were the same between the models for the two parameter sets in the cases of all threatened species. The models for two species with high occurrence and abundance, Galium tokyoense and Ophioglossum namegatae, yielded high accuracy (adj. R² > 0.7). We also found an autocovariate term related to the spatial autocorrelation of species abundance to be important in all the species examined. These results suggest the effectiveness of hyperspectral-remote sensing of shoot densities of P. australis and M. sacchariflorus in habitat modeling of locally abundant threatened species in moist tall grasslands.

　Recovery of lost or degraded vegetation and plant diversity is an important but often difficult step in the wetland restoration processes. At Lake Kasumigaura, Japan, a project was launched in 2002 to recover lakeshore vegetation using soil seed banks as the plant material. In this project, lake sediments containing soil seed banks were spread thinly (~10 cm) on the surfaces of artificial lakeshores with microtopographic variations, which were constructed in front of the concrete levees. In total 180 species, including six endangered or vulnerable plants and twelve native submerged plants that had disappeared from the above-ground vegetation of the lake, were recorded on five restored lakeshores (totally 65,200 m²) during the first year of the restoration project. The distribution of each recolonized species suggested the importance of arrangement of ground height for restoration of species-rich lakeshore vegetation. Foreseen changes in the vegetation, such as the disappearance of disturbance-dependent species from the above ground vegetation, replacement of submerged-plant dominated vegetation by Typha-dominated plants, and the invasion of the invasive exotic, Solidago altissima, were recognized in the early stages of monitoring at the restored sites. Vegetation management including selective removal of the invasive exotics started as a collaborative activity among citizens, government and researchers. Here, we summarize the methods and achievements of the vegetation restoration and management.

　Here we propose an adaptive management scheme for wetland restoration using data collected by citizens to make scientific predictions. We assessed the potential advantages of such a scheme using a wetland restoration project conducted in a small floodplain area along the Matsu-ura River in Kyushu, Japan. For the case study, we compiled data provided by amateur naturalists on distribution patterns of dragonflies on the eco-regional scale, as well as ecological characteristics such as behavior and habitat preferences. Based on this information, we predicted a species recovery trajectory at the wetland restoration site. By monitoring species recovery to test our prediction, we demonstrated that colonization by dragonfly species at the restored site could be predicted using species prevalence on the regional scale based on the nestedness rule. The data collected by the amateur naturalists were critical in making this prediction, which highlights the importance of citizen participation in the proposed scheme.

　Most of the wetlands on Hokkaido Island are peat-forming mires and constitute one of the most important principal ecosystems characterizing the natural landscapes of Hokkaido. However, more than 70% of the original mire area has been lost through transmigration and land reclamation since the Meiji era (approximately 130 years ago). Nowadays, 150 wetlands remain in both mountainous regions and lowland areas. They are characterized by various types, formations and development processes and there is an urgent necessity to protect and restore them. Especially regarding lowland mires, there are serious problems such as land subsidence, declining water tables due to drainage and increasing mineral soil or eutrophic water run-off from rivers and agricultural lands. As a result, mire vegetation has been undergoing retrogressive succession. A number of scientific research projects are being carried out in order to clarify the processes and mechanisms of mire ecosystem change and degradation. In addition, methods of conservation and restoration of mire ecosystems have been advancing. Furthermore, enforcement of the ‘Law for promotion of nature restoration’ and revisions of various laws have promoted the activities of non-governmental organizations, administrations and researchers.

　Living peatlands are often intricate systems with important self-regulation mechanisms to maintain the balance between ‘vegetation,’ ‘water’ and ‘peat.’ An important part of this self-regulation is directly associated with vegetation, which is generally ignored or insufficiently acknowledged in hydrological approaches to peatland restoration. This paper illustrates the ecohydrological complications of restoration of recently degraded peatlands in Tibet (China) and Kalimantan (Indonesia).

　On the Ruoergai Plateau (China), long-term grazing has changed many original percolation mires into more vulnerable surface-flow mires that since the 1950s have become subject to overgrazing and drainage. In Kalimantan, especially since the 1990s, peat swamp forests have been disturbed by drainage and deforestation. For both areas, different peatland degradation stages are distinguished with their own restoration perspectives and approaches. Because restoration of severely degraded peatlands is extremely difficult to achieve, the highest priority is the identification and protection of undisturbed mires and the prevention of further degradation. In both areas the restoration of the water retaining and storing role of vegetation is indispensable to prevent the peat body from further erosion and to provide adequate conditions for the regeneration of living mires. As the vegetation in both peatland areas is the main object of human exploitation (overgrazing, deforestation), peatland restoration is not only a matter of technical management, but has an important social dimension.

　Mires and peatlands have become the focus of nature conservation and restoration management policy due to their multiple ecological functions such as accumulation, disposal, retention and conservation, as well as their possible role in global climate regulation. In this paper we present the results of four long-term studies on spontaneous as well as directed revegetation of peat-mining areas in raised bogs situated in the foothills of the Alps in southern Germany. The results clearly show that

　(1) peat mining techniques affect spontaneous revegetation, peat-cutting being a technique which may allow peat-forming vegetation to reestablish itself after abandonment of peat-mining. In contrast, peat milling leads to mono-dominant successional stages of certain species that remain stable in their respective stages over decades,

　(2) hydrological conditions after renewed inundation (rewetting) affect the reestablishment of peat-forming vegetation. In our case study, rewetting caused the flooding of large peat-mined areas, resulting in the extinction of trees, shrubs and dwarf shrubs. However, it also supported the establishment of floating mats consisting mainly of fen species which may initiate, in the long-term, the reestablishment of the former peat-forming raised bog vegetation and

　(3) reintroduction of vascular plants typical of raised and transitional bogs by sowing and planting may accelerate the establishment of a dense vegetation cover as a prerequisite for the establishment of other species. However, the establishment of a Sphagnum cover with typical peat-forming species such as Sphagnum magellanicum has not been successful on a short- or mid-term basis and remains a major challenge in restoring cut-over raised bogs.

　Oriental white storks (Ciconia boyciana) became extinct in Japan in 1971. After successful breeding in captivity, a pilot release program was started as the first step toward reintroduction in 2005 in the Toyooka Basin, the last region this bird inhabited in Japan. As the oriental white stork is carnivorous and uses a variety of animals in its diet, restoration of its foraging habitat is an important part of the reintroduction project. Although this bird chooses good foraging sites seasonally in response to shifting habitat conditions and the amount of prey available, paddy field systems, including ditches and shallow rivers are relatively important to its foraging. At present, several restoration projects have been established in the Toyooka Basin. To ameliorate the habitat quality of paddy fields, a new farming scheme, including installation of “fishways” connecting paddy fields and ditches, prolongation of the period of paddy field flooding and application of reduced amounts of agricultural chemicals, was introduced to local areas in 2002. In addition, a project to create a shallow riverbed along the side of the Maruyama River in the Toyooka Basin was begun in order to improve the river channel to prevent flooding and to restore wetland habitat. These projects are being performed with the collaboration of local stakeholders.