Rice fields are important for both rice production and the great biodiversity they possess. Paddy rice landscapes parallel some of the most diverse “natural” systems on Earth, having more than 100 useful associated plant species and an enormous diversity of insects, fish, invertebrates, birds, and small mammals. This biodiversity is essential to the livelihood of poor farmers, who largely depend on it as a “free” source of food, medicine, timber, fuel, and fodder, as well as for manufacturing domestic tools, utensils, and handicrafts. It is free because there is no need to “buy” biodiversity—which is crucial since poor farmers do not have enough money to buy their basic needs from the market.
Biodiversity in rice fields is vital in supporting farmers’ livelihood and in regulating ecosystem processes and integrated pest management. As such, this rice landscape can be considered a multiresource agroecosystem. In current terms, the availability of such resources offers multiple ecosystem services.
The collection and consumption of wild food plants from agricultural landscapes have been documented in multiple cultural contexts, illustrating their importance to farming households throughout the world in many agrarian societies. Wild food plants are critical sources of nutrients, flavorings, and local medicinal remedies. They even serve as famine food in times of scarcity. Such plants, which provide a balanced diet, are essential to children and women, particularly those with scarce resources.
In northeast Thailand, the largest and poorest region of the country, wild food plants from rice fields have become essential in ensuring household food security among farmers. These wild food plants are herbs, shrubs, vines, and trees that grow in diverse habitats in the rice landscape. Nevertheless, 30% of these plants are regarded as “rice weeds,” which some agronomists suggest should be removed.
Farmers in northeast Thailand also harvest insects, fish, birds, frogs, crabs, snails, and rats from their fields and include them in their diet—representing an important means of saving income. Wild foods (plants, animals, and mushrooms) are an important component of local dishes and the culinary tradition of this region. Furthermore, the economy of many families depends on the commercialization of these resources, which is mainly carried out by women.
Traditional farmers maintain diverse aquatic, semiaquatic, and terrestrial habitats that interact ecologically throughout the rice landscape. Hillocks, shelters, pond margins, roadsides, and tree rows are examples of terrestrial habitats. Dikes—which could be dry or flooded depending on rain/irrigation conditions—constitute semiaquatic habitats. Field ditches and water ponds remain flooded during most of the year, providing aquatic habitats for wildlife. Wild plant communities that consist of trees, shrubs, vines, bamboos, herbs, and/or aquatic plants are different for each of these habitats. The distribution of plant diversity is not only related to the species’ water tolerance and life cycle, but also to the different degrees of management they have. The way farmers manage rice landscapes and wild food plants influences their abundance and distribution. Farmers mainly preserve culturally valued species, such as those that are key ingredients of important local dishes or that have multiple uses.
This situation is different in central Thailand, where rice production is more intense and the landscape more homogeneous. In this region, rice landscapes have fewer biodiversity-rich habitats (such as ponds, hillocks, tree rows, and shelters) than in northeast Thailand. The brown planthopper outbreak in 2010 affected the Central Plains of the country (known as the “rice bowl” of Thailand) because of the lack of natural enemies to the hopper, according to Dr. K.L. Heong, expert in integrated pest management at the International Rice Research Institute (IRRI).
Biodiversity-rich habitats are important to local farmers and livelihoods because they are also home to the natural enemies in the fields. In a village in Kalasin Province (northeast Thailand), more than 80 wild food plants are consumed, including tamarind and neem tree; aquatic plants such as water lily, water hyacinth, and water spinach; weeds such as false pepperwort ducklettuce and rice paddy herb (Limnophila aromatica); herbs such as amaranth (Amaranthus viridis); and vines such as the fetid passionflower (Passiflora foetida).
Nevertheless, in the last 20 years,many changes have affected the region such as the intensification of agriculture (including the introduction of agrochemicals and mechanization), migration of the farming families’ younger generation to urban areas to earn extra income, and deforestation. These changes may be a threat to the availability of wild food plants, which clearly are an important source of income that helps sustain livelihoods among poor farmers.
Overapplication of pesticide and herbicide
Biodiversity often puts farmers in a dilemma. On the one hand, they believe wild food plants are healthy; on the other hand, they know these plants are likely to be contaminated by pesticides applied in rice fields and are therefore unhealthy. Most farmers do not collect wild food plants during the 3 weeks following pesticide application. Some, however, have separate fields growing rice and wild food plant collections (where pesticides are not applied at all). A good example is water spinach, which grows in rice-field ditches, dikes, and ponds, and under dry and flooded conditions.
This plant is an important component of the poor families’ diet and is frequently consumed. Nevertheless, it can also be a weed and a target of common herbicides used in the area. Migration, labor shortage, mechanization, and loss of biodiversity In most rice-farming villages in Kalasin Province, many young people opt to move to the main cities to earn more income.
This has caused serious labor shortages for rice cultivation. At the same time, mechanization, primarily aimed at saving time and labor, has been increasing. In the mechanization process, there is a clear trend toward landscape homogenization, which eliminates many habitats—such as hillocks and shelters—to facilitate the use of tractors. These areas provide the greatest biodiversity of vegetables, fruit trees, vines, and edible insects. This also results in the loss of a valuable food medicine source for poor farmers.
Migration, labor shortage, mechanization, and loss of biodiversity
In most rice-farming villages in Kalasin Province, many young people opt to move to the main cities to earn more income. This has caused serious labor shortages for rice cultivation. At the same time, mechanization, primarily aimed at saving time and labor, has been increasing. In the mechanization process, there is a clear
trend toward landscape homogenization, which eliminates many habitats—such as hillocks and shelters—to facilitate the use of tractors. These areas provide the greatest biodiversity of vegetables, fruit trees, vines, and edible insects. This also results in the loss of a valuable food medicine source for poor farmers.
Potential loss of traditional knowledge
The trends of modernization threaten traditional knowledge about wild food plant identification, management, preparation, and use. Young people’s migration away from rural areas is disrupting common mechanisms of knowledge transfer, because village populations mostly consist of children and their grandparents (adults older than 50). Currently, children learn from their grandparents, but, in the near future, they are likely to leave the village as their parents did. Furthermore, children’s food preferences are shifting to vegetables mostly consumed in the cities, for example, cucumber, tomato, lettuce, and carrot.
Given the importance of wild food plants from rice landscapes, the trends in the loss of biodiversity and traditional knowledge are alarming. To preserve wild food plants as a resource for local communities, a holistic and integrated approach to rice landscapes is vital in order to maximize the benefits for resource-poor farmers. In many traditional systems, rice is but one of the many harvests from rice fields.
Hence, it is crucial to consider this for local livelihoods, food security, and the environment.