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If farm ponds are conceptualized as complex ecosystems, their role in wetland conservation planning is quite evident. In this section, we address three conservation policies, including public awareness building, top-down regulations and bottom-up engagement, and sustainable management and utilization, as well as three technical approaches, including inventory mapping, IoT-based collaborative monitoring, and numerical assessment, from similar practices in, but not limited to, wetland protection. These methods are oriented to the small, scattered characteristics of farm ponds, and involve various stakeholders, including community members and government sectors,to ensure a long-term, collaborative conservation framework in developing countries. Fig. 2.5 shows how these methods, stakeholders and pond landscape may fit together logically, and each of the methods is discussed in the sub sections below.
Fig. 2.5 A technopolitical framework for conserving farm ponds
The critical first step of public awareness building is to ensure that the terms“small wetlands”“freshwater ecosystems”and“landscape degradation”are in the lexicon of farmers, local officials, rural planners, and urban visitors. Education serves as a formal and fundamental method to build such environmental awareness and to make conservation knowledge explicit and widespread (Varela-Losada et al., 2016). In addition to classroom education programs, on-site environmental activities can enhance student learning and instill an intrinsic valuation of nature. For example, survey data indicated that primary school students exhibited increased interest in soil and water sciences and willingness to protect red-crowned cranes after four seasonal visits to the Zhalong Nature Reserve, northeastern China (Zhao, 2006).Environmental-friendly attitudes and behaviors have also been demonstrated to be transferable from children to their families (Damerell et al., 2013),which is important because animal feeding operations and household water management are closely related to the ecosystems of farm ponds.
Informal education by means of newspapers, radio, television, and the internet, is more flexible and diverse, translating scientific findings into policy and converting environmental knowledge into action for various stakeholders(Greenhow and Lewi, 2016). For example, the Vernal Pool Association has operated a promotional website since 2005 and identified more than 300 vernal pools in conjunction with their invertebrates’lifecycles in Massachusetts,US, where the filling and draining of ephemeral ponded wetlands is prohibited.Similarly, in the intertidal zones of Zhejiang Province, 8,000 popular science readings and 1,000 wildlife photo albums were compiled and disseminated to rural residents during World Wetlands Day and Bird Loving Week from 2011 to 2014. These substantial investments in public education have helped to implement a strong regulatory basis for the restoration of mangrove swamp and estuarine wetland (Tang, 2015).
Regulations promoting the conservation and management of small,scattered wetlands may range from restrictive local protections at the pond scale and across hundreds of meters of adjacent habitat at the landscape scale to broader national guidelines and international commitments (Biggs et al.,2010; Fang et al., 2014; Mitsuo et al., 2014). At any governmental level, top-down regulations have the advantage of setting clear rules but usually lack local understanding and enforcement jurisdiction of the various stakeholders being regulated. This is particularly true for farm ponds, which are sometimes closely related to agricultural activities and rural life. Hence, their management may best be achieved by combining top-down approaches, which set an overall standard, and bottom-up engagement, which ensures effective complements via more tailored and voluntary actions. For example, vernal pool conservation regulations at the federal and state levels only include formal definitions,criteria to support pool prioritization, and a basis for delimiting buffer zones,while local programs are more concerned with the economic benefits of land use and the surrounding flora and fauna in Maine, US (Calhoun et al., 2014).
Top-down regulations have gradually shifted from rivers and lakes to small,manmade, or natural shallow waters in developed countries, as the latter are numerous, typically outnumbering the larger waters, and can be regarded as biogeochemical hotspots in virtually all terrestrial environments (Leibowitz et al., 2018). For example, the US Environmental Protection Agency concluded that ponded wetlands are effective in riverine nitrate removal and thus are“waters of the US”under the Clean Water Act (Leibowitz et al., 2008). The EU Water Framework Directive has recently recognized the importance of intermittent headwater streams due to their vulnerability to anthropogenic pressures and significant influence on downstream water quality (Lassaletta et al., 2010). However, such“legal”standing for farm ponds is lacking in China's environmental legislation. Following the institutional reform of the State Council in 2018, the Ministry of Ecology and Environment, together with the Ministry of Natural Resources, Ministry of Water Resources, and Ministry of Agriculture and Rural Affairs, recommended standardization of construction, operation,and maintenance of farm ponds, especially those in disrepair or in areas vulnerable to floods and landslides. These ministries would also be responsible for the proposal of relevant laws and regulations, such as“Procedures to Build a Farm Pond”“Plans for Farm Pond Protection”, and“Farm Pond Restoration Provisions”.
Meanwhile, bottom-up initiatives must be encouraged. On-site pond conservation programs usually require understanding of natural conditions (e.g.,hydrology, soil, and geology) and agricultural practices in peripheral areas. The involvement of local communities can provide such information and also help to enhance the effectiveness and continuous improvement of those programs(Calhoun et al., 2014). Citizen science has become a popular way to engage“nonprofessionals”in ecological assessment and environmental protection across scattered areas (Zheng et al., 2017). With regard to farm ponds,recruiting voluntary or somewhat incentive-based farmer scientists and holding regular workshops for their family members is recommended to foster a sense of responsibility, mutual surveillance, and eventually collaborative conservation,as has been tested in farmer-participatory rural reform in the Chenzhuang village, Jiangsu Province (Yang and Chen, 2017; Chen et al., 2018).
Like participant incentives, conserving natural resources is also sometimes expensive and time-consuming owing to the need for infrastructure,maintenance, informational material, etc. Therefore, it is essential to develop partnerships with different communities and identify opportunities to meet disparate goals with desirable outcomes for various stakeholders (Spiteri and Nepalz, 2006; McGreavy et al., 2012). In southern Saskatchewan, Canada,for example, prairie pothole protection is combined with govern funding and investments from nongovernmental organizations (Rashford et al., 2011). To introduce up-to-date technologies and management skills in urban stormwater management, Chinese authorities have adopted the participation of private and foreign investors since the late 1990s. Their cooperation has started a unique form of Public-Private Partnership (PPP) projects, which take advantage of top-down regulation from government sectors and the flexible operation of market-oriented entities (Lee, 2010). Despite potential operational risks,including postponed approvals and imperfect supervision, these diversified opportunities are referential to farm pond conservation, especially when funds and techniques are limited.
Small, scattered wetlands are arguably best managed using the meso-filter strategy (Hunter, 2005; Hunter et al., 2017), where features that may be integrated ecosystems in their own right, or ecological elements within a larger context can, by nature of their small size, move towards sustainable management. As a unique natural-economic-social complex, farm ponds also require appropriate management to collect stormwater, mitigate flood risk,and provide considerable economic and cultural benefits in rural areas (Yin and Shan, 2001; Mitsuo et al., 2014; Yu et al., 2015). In view of their importance to both nature and humanity, such management needs to incorporate approaches that range from within-pond practices specific to water and sediments to landscape-scale strategies that recognize their functions as wetland complexes that are embedded within, and may be integral to, larger ecosystems.
From historical documents on paddy planting to recent water conservancy practices, farm pond management, including dam design and construction and pond repair and dredging, have always been highlighted in southern China. For example, early in the Spring and Autumn Period, The Records of Examination of Craftsman proposed that a dam's cross-section should be trapezoidal in shape and the slope of the trapezoid edge is recommended to be 1∶1.5 to 1∶2.0 for structural stability. With regard to regional pond planning, The Huainanzi Shuolin Discourse compiled in the Han Dynasty stated that waters with a total area of 0.1 km 2 and an average depth of 2m can mitigate droughts in surrounding farmland of 0.4 km 2 , indicating that a pond density of 25% is appropriate for agricultural irrigation. Pond repair and dredging were biyearly carried out after crop harvest between the Yangtze and Huai River (Lü and Chen, 2014). Despite increasing flood risk and soil erosion due to climate change and a dwindling number of small farmers in the countryside, these management traditions are indispensable to maintain water capacity, improve water quality, and promote nutrient cycling.
Protecting farm ponds from degradation and destruction is a multi-scale issue that requires broader perspectives and strategies. For example,conservation prompts, such as“Don't litter”signs, have proven useful to reduce floating wastes from rural households and tourists, as they are highly specific, proximal to a site, and can be stated in a friendly manner to motivate one's responsibility (Osbaldiston and Schott, 2012). In addition, following the experience of water caltrop planting in Anhui Province and Phragmites growing in Hunan Province (Liu et al., 2009; Tian et al., 2011), special attention needs to be paid to aquatic vegetation, as it provides habitat to amphibians and benthic invertebrates and is easily consumed by the farmed fishes. In addition, low-impact development, including the use of pervious pavement and the construction of rain gardens and forested buffers in riparian areas, is encouraged in rural areas, as it has been included in urban planning. When constructed at an optimized density and connectivity, farm ponds can act as nature-based“sponges”(Yu et al., 2015; UN-Water, 2018), reducing nutrient loads into downstream waters (Hansen et al., 2018; Leibowitz et al., 2018).
To effectively manage and conserve farm ponds individually and at a landscape scale, it is essential to have a spatially explicit inventory combined with a collection of the hydrological and ecological status of the ponds,including information on the adjacent agricultural matrix. Remote sensing methods have been widely used to analyze pond dynamics, e.g., the loss rate and driving forces in the Taoyuan tableland (Fang et al., 2014), but farm ponds are rarely mapped at large scales, as they are usually disregarded or not documented in places where wetland inventories are compiled and are difficult to automatically update from high-resolution, nationwide imagery (Tiner et al., 2015; Wu et al., 2018). In addition, the ability to identify farm ponds varies greatly depending on the natural conditions, such as water level fluctuations and adjacent vegetation coverage. For example, in evergreen and mixed forest landscapes in the northeastern US, only 43% of the confirmed temporary pools were detected by aerial photography. Even in open areas, remote detection can be limited by atmospheric conditions and the spatial resolution of the sensors being used (DiBello et al., 2016). However, technological advances are constantly improving this work. The availability of high-resolution light detection and ranging (LiDAR), synthetic aperture radar (SAR), hyperspectral,and multispectral data has increased the feasibility of detecting water bodies as small as 1 1 m. Moreover, the introduction of multisensory and multi-scale data fusion techniques has enabled the large-scale mapping of small wetlands with unprecedented accuracy (Tiner et al., 2015).
Despite the abovementioned management constraints and technological challenges, inventory maps of ponded waters can be developed at multiple scales from field surveys, image interpretation, and voluntary programs using farmer scientists to identify their location, extent, and ecosystem structure (Calhoun et al., 2014), to conduct large-scale inventories associated with hydrological and ecological assessments to better support research,management, and government initiatives, as has been done in other specialized databases with numerous, scattered points of interest (Chen et al., 2016b).
Recent developments in environmental monitoring have enabled quantitative descriptions of the physical, chemical, and biological characteristics of water bodies over time and space. In this process, one of the most important features is the Internet of Things (IoT), which provides a network of various smart devices that sense, interpret, and react to the environment (Perumal et al., 2015). Owing to their low cost, ease of access, and tailored devices, IoT-based techniques have inspired engineers and private entities to either build their own sensors or modify off-the-shelf equipment to realize the integrated and real-time detection of hydrological, water quality, aquatic biota and soil conditions. For example, in Hubei, Jiangsu, Guangdong, and other provinces,connected sensors coupled with imbedded knowledge base have facilitated the aquatic plant growth, nutrient management, and disease prevention in shrimp breeding ponds, transforming traditional inland fisheries and aquaculture into data-driven and intelligent activities (Ma et al., 2012).
Collaborative efforts from different communities can expand the horizons of environmental monitoring and complement infrastructure and fixed observation stations. For example, mobile phones with GPS, photography, and social media applications have proven effective in collecting data on the color and transparency of surface waters by citizens, as has been implemented in the River Chief Mechanism (Zheng et al., 2017). Simple and inexpensive water test kits, available from many pet stores or online retailers, are useful to small farmers when preventing water quality degradation in fish ponds (Naigaga et al., 2017). High-throughput sequencing of DNA extracted from water samples serves as a quick, cost-effective and standardized method for scientists and conservation agencies when evaluating rare and threatened species across a wide range of taxonomic groups (Thomsen et al., 2012). By properly integrating these discrete results with consecutive data, IoT-based monitoring can be extended to a human-centered network with wide community involvement.Fig. 2.6 shows an integrated monitoring system being developed for farm pond conservation in the Chenzhuang village. Although this is a long-term effort, the GIS-based data framework will provide a solid basis for understanding pond ecosystem services.
To balance the costs and benefits of farm pond conservation, the hydrological, biogeochemical, and biodiversity functions that support ecosystem services and socioeconomic value should be assessed in a standalone or comprehensive manner (Fang et al., 2014; Hill et al., 2018). For example, based on streamflow observations, Gao et al. (2016) discovered a decreasing trend of water retention from downstream to upstream in the pond landscape of Chenji town. Chou et al. (2013) employed questionnaires, the fuzzy Delphi method,and an analytic hierarchy to assess the habitat suitability of pond-breeding amphibians in Yunlin County, Taiwan, China. Taking aquatic environments, terrestrial settings, and landscape connectivity into account, their results revealed that 19% of the 481 farm ponds were rich in frog species with high conservation value. In contrast to these single-criteria analyses, the vernal pool assessment in the northeastern US relies on both indoor and outdoor citizen-training sessions, as the former requires aerial photointerpretation and GIS to delineate waters, and the latter includes field surveys of egg masses,amphibians, and invertebrates (McGreavy et al., 2012; DiBello et al., 2016).Applied in a larger context, this method can provide a detailed assessment of aquatic features but requires labor-intensive efforts to establish a sound monitoring database beforehand.
Fig. 2.6 The data framework of an integrated monitoring system for farm pond conservation
Process-based models, which are based on a theoretical understanding of ecological processes and a set of computer programs, are useful to assess wetland dynamics and associated conservation decisions, especially when the required data are discrete and deficient (Ongley et al., 2010). Popular model categories include (1) watershed models, such as SWAT, HSPF and AnnAGNPS,which describe rainfall-runoff processes and often include an associated biogeochemical module that routes point and nonpoint source pollutants from the landscape to the stream, (2) hydrodynamic and water quality models,such as WASP, FEWMS and EFDC, which emphasize flow circulation, pollutant fate and transport and the interactions among the sediment, nutrients,phytoplankton and macrophytes in surface waters, (3) groundwater models,such as MODFLOW and HydroGeoSphere, which estimate the movement of subsurface flows through saturated porous media, and (4) ecosystem models, such as AquaSim, Ecopath with Ecosim and AEMON, which quantify the ecological relationships and evaluate the costs and benefits of wildlife conservation (Golden et al., 2014; Janssen et al., 2015; Rains et al., 2016).Although these models are deliberate in their respective domains, detailed modeling of pond dynamics is more complex, as it simultaneously includes surface and subsurface hydrological processes, biogeochemical cycles in ponds and ditches, and ecological processes at various spatial scales (Rains et al., 2016; Chen et al., 2018). Therefore, appropriate integration of these models is expected to assess the ecosystem services of farm ponds individually and comprehensively.
To make the modeling tools more immersive and comprehensible, several emerging techniques can be employed, such as serious games and gamification and augmented and virtual reality, which have been tested in land management(Schulze et al., 2015), water resource protection for over-pumped aquifers, and climate change adaption involving sociopolitical events, energy consumption,population growth, etc. These technical advances are helpful to illustrate interdisciplinary teaching and education regarding pond conservation and the complex interrelations between the ponds and human well-being.