Proposed zoning
Using information derived from the CPS process, and given most of the surrounding land is semi-arid and has little conservation interest, we propose a refined zonation plan, differing from the existing by:
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reducing the surrounding farmland with little conservation value by 150 km2;
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slightly modifying the area of existing zones; and finally
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rename and suggestion of a new zone: risk-control zone
Core zone
The core zones are those of highest conservation value, with minimal human intervention so as to maintain ecosystem as integrity and minimise disturbance. In WNR, GSR, XHZ and CSK are suggested to be retained as core zones (Figure6), since they are typical wetland landscapes with high numbers of visiting birds and low physical disturbance. The southern site (CSK, 12.77 km2), middle site (GSR, 55.31 km2), and northern site (XHZ, 15.87 km2), total (83.95 km2), take up 20.4% of the area (Figure6). Key species such as Cygnus olor, Platalealeu corodia breed in these areas. Ciconia nigra and Haliaeetus albicilla also forage here.
Limited-use zone
Many authors (Dudley and Stolton2008, Xu et al.2007) recently have drawn attention to the need for wetlands to be considered in a broader landscape, or wetscape (Bridgewater 2008), context, with appropriate links and connectivity developed between different landscape elements. To some extent, the proposed limited-use zone functions as a buffer in minimizing negative and external effects of human activities on the core areas, but also promotes connectivity between the zones and the wider landscape. Although the core zones should be fully and effectively (i.e. legally) protected, Limited-use zones also should have some protection, so that they valign="top" can be designed to allow low-intensity sustainable use, helping maintain their function for both biological and cultural diversity valign="top" conservation.
To achieve these objectives we suggest a 1km area around the core zones as a limited-use zone to assist with maintaining ecosystem integrity of ecological processes. This limited-use zone (Figure6) also connects the core zones of GSR and XHZ, which are visited by local populations of swans, ducks, shore birds, and breeding grounds of Cygnus olor. The area of suggested limited-use zone is 92.51 km2, or 22.4% of the WNR.
Wise use zone
The Ramsar Convention defines wise use of wetlands as “the maintenance of their ecological character, achieved through the implementation of sound ecosystem approaches, within the context of sustainable development, to maintain environmental, economic and social sustainability in land use decisions, encourage compromises (“trade-offs“) between individual and collective interests.” (Ramsar Convention 2005). Using this definition we suggest the term wise use zone for areas with multiple land uses, but retaining a key role in delivering conservation through sustainable development.
Based on these concepts for zonation, our suggestion is to set the boat harbour, bird watching tower, fishery, and its adjacent water body as wise use zones (Figure6), with an area of 132.47 km2, taking 32.1% of the total reserve area. These wise use zones are designed to maintain good conditions for fisheries, other harvesting traditions and wetland culture.
Risk-control zone
In semi-arid regions lake ecosystems are usually vulnerable, with a range of external threats being a major risk to maintenance of their ecological character. The main non-point pollution of Wuliangsuhai Lake is from irrigation water. Maintenance of water quality benefits vary with the size of the buffer, the flow pattern, vegetation type, percent slope, soil type, surrounding land use, pollutant types and dose, and precipitation patterns (Sheldon et al.2005). To relieve and remove ecological risk, we propose an area of drainage and canal systems in the west shore and its adjacent reed swamp should be set as a risk-control zone (Figure6), with an area of 103.8km2, taking 25.1% of the area. Projects and programs such as pollution treatment, ecological restoration and biological conservation should be conducted in the zone to restore, and or maintain ecosystem function. The “experimental zone” in the existing zoning plan is largely sympatric with the wise use zone, although there is some overlap with the proposed risk-control zone.
The risk-control zone is of great importance. Agriculture activities outside WNR represent the main threat to the wetland ecosystem functioning, and thus service delivery. As a principal driver for wetland degradation, excessive fertilization contributing to the processes of eutrophication are directly or indirectly reinforced by valign="top" climate change. And, for WNR, a major consequence of eutrophication is the extension of reed swamps, rapid growth and spreading of aquatic macrophytes, and the development of algal blooms, in particular, during warm summer periods. Remote sensing imagery has shown that from 1975 to 2001, the area within WNR dominated by reed swamp has increased by six-fold (Hou and Deng2005). Shang et al. (2003) pointed out that the deposition of dead aquatic macrophytes into WNR lake was about 20.5 × 104t DW per year. Historic data show that the area of open water in WNR has shrunk from 660 km2 in 1950s into 270 km2 in 2000 (Yu 2003),In the absence of active management within 30 years the current WNR would seem destined to become completely valign="top" covered by reed swamp; and thus inimical to most of the bird species for which the area is designated a reserve. The risk-control zone is a new effort to deal with such kind of ecological risk.
We have established that four spatial zones provide the maximum conservation benefit for the key objective of managing for migratory birds during their period of residency. However, we also advocate viewing those zones through a temporal lens, and modifying management efforts appropriately by varying the zonation structure and consequent management or monitoring efforts on an annual basis. We are able to prescribe this dynamic zoning structure for WNR on the basis of the adequacy and extent of available data, as following:
The four zones are especially effective from March to November (Figure7A; Figure7B) In March, however, the southern part starts melting and the early arrival migratory birds forage in the CSK core zone, which can be regarded thus as the key valign="top" core zone for that period of the year (Figure7A); while from April to October, most birds are resident in the XHZ and GSE core zones (Figure7B). However, in ‘winter’ (December to following February), the whole lake is iced-over and all the birds emigrate; therefore a two zone structure - wise use and risk-control - are suggested for WNR during that period to allow for more efficient conservation effort (Figure7C).
While the zones described above are presented as fixed spatial entities, the highly dynamic nature of WNR suggests a role for temporal as well as spatial zonation. Ecosystem management that allows for different management strategies to be expressed temporally helps achieve clearly enunciated conservation targets. As we have described the overall target for WNR – conservation and maintenance of migratory wetland bird populations - is seasonal in nature. Learning from nature and seizing the “right” time to maximise conservation is essential to developing an efficient management system. Accordingly, we suggest a system of dynamic zoning on an annual basis would further improve the effectiveness of WNR management. The premise of such dynamic zoning assumes a deep understanding of ecological processes at spatial and temporal scales, which we believe exists for WNR.
Despite many studies carried out to select or determine the shape, size and the optimal placement of nature reserves (Blouin and Connor 1985, Buckley 1982, 1967, Higgs 1981, Higgs and Usher 1980, Li et al. 1999, Mac Arthur and Wilson 1967, Margules et al. 1982, Usher 1986), few practical studies for designing the interior structure of nature reserves, especially wetland reserves, have been published. Although no quantitative comparison has been made to the effectiveness of those different zoning patterns, this is the first endeavour to improve the existing zoning of WNR. It is quite true that each wetland has its own ecological characters. However, many of the wetlands are characteristic of dynamic change in vegetation, hydrology, migratory water bird population, etc. Therefore, the process to ecological character description and the zonation we propose for WNR would probably serve as an example, or new alternative to improve the basis for zonation establishment, which may have wide applications for wetland reserves that characterized by seasonal hydrological cycle, migration ground for birds, as well as under strong human use. Such zonation, taking account of human activity as well as that of wildlife, can help resolve the conflict between the objectives for nature conservation and community aspirations, and promote effective conservation and sustainable development for both nature and society.