Biodiversity for Food Security: The Giant Swamp Taro ‘Dalugha’ from Sangihe Islands, North Sulawesi, Indonesia

Biodiversity provides environmental services, foods, drugs, fibers and timbers for humans. The value of biodiversity to the Indonesian people is enormous. To feed its ever-growing population, the Indonesian government has made improving food security and food sovereignity a national priority. Achieving food security is intrinsically linked to the maintenance of biodiversity. This research was conducted in Tamako District, Sangihe Islands, North Sulawesi. One of the most serious threats to biodiversity is climate change. Small islands can be impacted by extreme weather events, rising sea levels, and the effects of climate change. Local or native crops play important role in enhancing food security. Giant swamp taro Cyrtosperma merkusii known by local people as Dalugha is one of main staple food in the Sangihe Islands, North Sulawesi, Indonesia. Prior to the introduction of rice, sago, cassava, and giant swamp taro were staple dietary sources for the Sangihe Islanders. Dalugha grows in swamps near the coast, where seawater inundates the swamp during high tide. It has a high nutritional value as a substitute food and easy to propagate. As a result, it is an essential crop for enhancing food security, especially in facing sea level rise and climate change.


Introduction
UN Convention on Biological Diversity defines biodiversity as the diversity of living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems, as well as the ecological complexes of which they are a part; This includes species diversity as well as ecosystem diversity.In the simplest term, biodiversity refers to the diversity of life.Indonesia is an archipelagic state with 17,000 islands spread across two continents (Asia and Australia) and the Pacific and Indian oceans.It contains two biodiversity hotspots (regions with a significant degree of endemic species that are severely threatened by habitat loss): Because of its isolation and complicated geological history, the island has evolved a globally diverse flora and fauna [1].
For humans, biodiversity provides food, medicine, fibers, wood, and environmental services.In Indonesian society, the value of biodiversity is deeply ingrained in fields like agriculture and traditional medicine.Indonesia has a population of around 275 million people spread across thirteen thousand inhabited islands [2].According to UN Convention on Biological Diversity's country profile, approximately 40 million people directly depend on agricultural, marine, coastal, and forest ecosystems for their survival.To feed its rapidly growing population, the Indonesian government has made strengthening food security and increasing food sovereignty a national priority.Achieving food security is intrinsically associated to biodiversity conservation.
One of the main causes of biodiversity loss and a major barrier to other species' equitable sharing of habitat and vital resources is human overpopulation [3][4][5].The loss of biodiversity is caused by several factors, including overexploitation, pollution, invasive species introduction, habitat loss, hunting, climate change, and natural catastrophes [6][7][8][9][10][11][12].According to UN Convention on Biological Diversity, the primary causes of habitat degradation and fragmentation include landscape alterations, excessive extraction, pollution, climate change, alien species, and land and forest fires are the main causes of biodiversity loss and species extinction in Indonesia.Research found that large-scale scale infrastructure development in Indonesia [13] and Borneo may endanger wildlife [14,15].
Biodiversity experiments have investigated whether declines in biodiversity affect the health of ecosystems or stability by modifying some aspect of biodiversity, such as the number of species, and measuring different types of ecosystem function or stability [7].The loss of biodiversity can lead to a decrease in the function of natural enemies in the ecosystem, the extinction of species, and the introduction of invasive species as a result of competitive displacement or a lack of food sources for the natural enemies.These factors have led to the emergence of invasive pest species, which pose a serious threat to Indonesia's biosecurity.The populations of invasive species grow out of control and seriously harm agricultural crops as a result of the absence or decline in natural enemy populations.This poses a threat to biosecurity.Studies indicate that when natural enemies fill distinct and complementary niches, there may be a stronger correlation between increased enemy biodiversity and pest suppression [16].
Rice is the staple food in most part of Indonesia, and its production also provides livelihoods for Indonesian farming households.Other staple foods of native people in Indonesia include sago and a number of starchy tubers such as yam, sweet potato, cassava and taro.Giant swamp taro Cyrtosperma merkusii known by local people as Dalugha is one of main staple food in the Sangihe Islands, North Sulawesi, Indonesia.Prior to the introduction of rice, sago, cassava and giant swamp taro has become a staple dietary source for local people of the Sangihe Islands.
Dalugha, giant swamp taro is known by the scientific names: Cyrtosperma merkusii and C. lasoides, C. edule and C. Chamissonis.According to Flach and Rumawas [17] the plant is not native to Sulawesi, but Van Dinter in 1899 and Vorderman in 1899 found it in Sangihe [18].This giant swamp taro is also found in the Pacific region, and is known as Puraka in the Cook Islands, Pula'a in Samoa, Via kan in Fiji, Swamp taro in PNG and Navia in Vanuatu [19].In Malaysia this plant is known as Geli-geli and Keladi pari, Palauan in Bisayan, Philippines, Kli in Thailand and Kakake in Solomon Islands [20].
This giant swamp taro is thought to have been brought from the Indo-Malaysian region to the Pacific, where it now grows in abundance, even on atoll island states.Tropical Asia and several Pacific nations grow giant taro as a food crop.It has a substantial stem, large leaves, and inflorescences [21].Giant swap taro is primarily grown on a small scale as part of subsistence farming.During famines, giant taro was grown as a subsistence crop [22].Dalugha has been introduced in Sangihe and cultivated by the locals and used as one of major diets over hundreds of years (Figure 1).
The largest member of the taro family and a lowland species is the giant swamp taro.It can grow alone or in cluster, reaching heights of four to five meters.It is one of the few crops that may be produced in the marshy sections of other islands and on atolls that is suited for subsistence farming, and its corm can weigh up to 80 kg [18,19].Example of Dalugha's corms is shown in Figure 2. Dalugha can be cultivated withing a range of temperature from 15.5°C to 38°C.The roots can reach 1-2 meters underground, and require effort to harvest.Although it can take several years to mature, harvesting usually occurs at least fifteen years later [19].
Field-stored giant swap taro can remain in the ground for up to 30 years or longer.Therefore, in times of natural disaster and food scarcity, it has historically served as an significant emergency plant in the Pacific region.Interestingly, this giant swamp taro has been grown widely in Solomon Island due to harvest failures of food crops [23].This crop has a good resistant on plant's pest and disease, but it is susceptible to the taro beetle.[19].
It takes some time to process because it is usually peeled, grated, and sundried before being cooked into sticky cakes.It can also be prepared by boiling it for 2 -3 hours before eating.In the graph, the nutrient content of 100-gram edible portions of white rice and boiled giant swamp taro is compared.Table 1 [24].Table 1 shows that the enormous swamp corm is a rich source of fiber, which is necessary for the intestines and bowels to function properly, and a great source of energy.Fiber also aids in the control of blood sugar in diabetics and the reduction of blood lipids, both of which are risk factors for heart disease.The vital minerals iron and calcium are both abundant in giant swamp taro.Iron and calcium work together to maintain healthy blood vessels and strong bones and teeth.Zinc, an important mineral that strengthens blood, guards against infections, and prevents vitamin A deficiency, is also abundant in giant swamp taro [25].
Giant swamp taro is used as medicinal plant in Micronesia islands [26].Dried corm has been used to cure skin infection in Kiribati [27].
This research was done to find out the important of Dalugha to local people of Tamako, Sangihe Island and the potential role of Dalugha in enhancing food security of this small island in facing climate change.

Materials and methods
This research was conducted in Tamako District, Sangihe Island, North Sulawesi (Figure 2).Data collection was done through field survey, interview and Focus Group Discussion with key informant.
The study team visited Tamako area and collected relevant data including: -History of Dalugha cultivation -Extended uses and applications (including commercial and medicinal) of Dalugha -Local cultivation of Dalugha -Local's value of Dalugha.How locals value of Dalugha will also enhance its cultivation, production and conservation -Challenges to Dalugha cultivation and further development Data on Dalugha habitats and plantations were obtained in the field during the site visit to Tamako District particularly in three villages namely, Naga Satu, Pokol and Balane.Data on local use of Dalugha were gathered through site visit to local market and interview with local people.Key persons in three villages and local Dalugha sellers were interviewed to find out about Dalugha cultivation history and Dalugha's values.Focus Group Discussion was held to find more information on local values on Dalugha, their expectation of Dalugha use and cultivation.Focus Group Discussion was attended by District and Village government, public and religious leader, women group, farmers and other relevant stakeholders.All data then was compiled and analysed descriptively.

Results and discussion
Dalugha is thought originated in the Indo-Malesian area and was brought to the Pacific, where it is currently found in a wide variety.This giant swamp taro of Sangihe has been introduced and cultivated by the locals since 1575.The corm was brought from Halmahera to Tamako by the local.In the past, it has been a crucial crop in Tamako during times of food shortage during World Wars I and II.During the wars, it was difficult to get food from the mainland.Locals called Dalugha as Makanan Perang 'War Food' because they can easily find, cook and eat this crop as a source of carbohydrate.Prior to the introduction of rice, sago, cassava, taro and Dalugha have become a staple food for local people of the Sangihe Islands.
In the Tamako District, Dalugha is grown on about 75 hectares.Dalugha plantations are found in three villages in Tamako namely, Naga Satu, Pokol and Balane (Figure 3).Prior to the introduction of rice, sago, cassava, taro and Dalugha have become a staple food for local people of the Sangihe Islands.

Research done by Liana et al, 2021 found that Dalugha is among 34 types of local foods in Sangihe
Island [28].Dalugha is a perennial herbaceous plant that grows in freshwater swamps and coastal swamps.When compared to other taro species, it has some shade tolerance and is moderately tolerant of saline habitat, and it can be grown in slightly salty water (Figure 4).Dalugha cannot be grown in highland or rain-fed conditions.This species is cultivated using setts, which are suckers, or cormlets, which are young, immature corms produced by a more mature plant.Dalugha is cultivated traditionally in home garden, agricultural field.No use of fertilizers and pesticides Dalugha matures between 1-2 years of age.
The Dalugha corm is a great source of calories, rich in fiber and essential minerals.Example of Dalugha's corms is shown in Figure 4.It is an alternative source of food staple especially for those who live on small islands.As earlier noted, Dalugha is not only found in Sangihe and but also its surrounding Islands in such as, Miangas, Makalehi and Biaro [20].Giant swap taro it is found in Malaysia, Thailand, Philippines and widely cultivated in the Pacific region.In fact, this plant has been critical to the region's food security [19].
Small islands are particularly vulnerable to the effects of climate change, sea level rise, and extreme weather events [29,30].This is largely due to their natural condition (surrounded by ocean), small land portion, and often distance from the mainland, which limits their connectivity to the world [30].Flooding, hurricane surge, and other coastal hazards are expected to worsen as sea levels rise, putting essential infrastructure, communities, and facilities at risk.Changes in coastal conditions, such as beach erosion and coral bleaching, are expected to have an impact on local resources.It is predicted that rising sea levels and warmer seawater will hasten beach erosion and weaken naturally occurring coastal barriers like mangroves and coral reefs.Vegetated wetlands along the coast are vulnerable to long-term changes in sea level and climate.Because most small island regions have a narrow tidal range, losses would be severe.It is highly unlikely that small island communities' agricultural livelihoods and food security will be enormously affected by climate change.A major vulnerability to climate change is agriculture.Temperature rises, changed precipitation patterns, and an increase in the frequency of certain extreme events are just a few of the ways that climate change is already impacting food production [31,32].A decrease in food production will disrupt food security.In addition, elevated temperatures gradually diminish the yields of preferable crops while promoting the growth of weeds and pests.Global food security is at risk due to the overall negative impacts of climate change on agriculture, notwithstanding the fact that some crops may prosper in some parts of the world.The populations most likely to be severely impacted are probably those in developing nations, where food insecurity and vulnerability already exist.According to an IFPRI study [32], the Asia-Pacific region will have the greatest impact on rice and wheat yields worldwide.Crop yields in parts of Asia are expected to fall by 2.5 to 10% in the 2020s and by 5 to 30% in the 2050s compared to 1990 levels without CO2 effects (medium confidence) [33].As was already mentioned, rice is the main food staple in the majority of Indonesia.It is necessary to reduce reliance on rice as the primary food staple in order to foresee the detrimental impacts of climate change on rice yield.Food diversification is a feasible option for lowering the risk of food scarcity.
Traditional food production systems are diverse and long-lasting.In this case, Dalugha has historically been an important emergency plant during times of natural disaster and food shortage.It is one of Indonesia's traditional staple foods especially in Sangihe Island.It is a crucial component of a balanced diet and highly nutritious as well, but it categorized as 'underutilized species by Global Facilitation Unit for Underutilized Species (http://www.cropsforthefuture.org/).This is the case in the Philippines, especially in Bohol, Giant Swamp Taro has little value as food; it is only consumed when nothing else is left to eat.After that, it is forgotten in favor of other foods [34].Muller [21] considers giant taro to be a neglected plant in the Pacific.
About 375 tons of roots are harvested each year and sold locally and used for personal consumption [20].Local people only eat boiled Dalugha or make crackers (ketang-ketang).Most local buy boiled Dalugha corms in the traditional market (Figure 5).It takes 3-4 hours to boil the corms.Due to long processing, the locals prefer to eat taro than this giant swamp taro.
Local people make crackers ketang-ketang from Dalugha.Ketang-ketang is the most popular 'oleholeh' from Tamako.Some locals order ketang-ketang to send to Jakarta or Manado.Commercial production of giant swamp taro is unlikely in Tamako because of the lack of demands.Other alternative food such as sago and taro can be found and cooked easily and are cheap.
Due to lack of knowledge of Dalugha processing, it has not as yet been converted into flour.Lumba et al. [35] made rice analogue from Dalugha.This rice analogue was found acceptable to the test panel based on smell, texture, performance and colour parameters.
For long-term food security purposes, Dalugha is a significant staple food crop.Dalugha can be cultivated and utilized to enhance food diversity and also ought to be created as a substitute national staple in the future.Dalugha is an underutilized crop that locals value as an important alternative staple food.It is high in starch, which is a great source of energy.When rice intensification program in the 80s introduced in Tamako area, Dalugha plantation was converted into paddy field.It was not a successful initiative in Tamako as local prefer to cultivate Dalugha than rice.Now, no paddy fields-Taro has been planted to replace paddy rice.For them, Dalugha is a local crop, native to Tamako District and it has a long history of facing food crises.

Conclusions
Local crops have a significant impact on bolstering food security on small islands like Sangihe.In Tamako during the war, it has historically been a significant emergency crop during times of food scarcity.It is called as Makanan Perang 'War Food'.In facing the detrimental effects of climate change on small islands, promoting cultivation of this giant swamp taro is a viable option.
Traditional food production systems are diverse and stable.Dalugha can grow in freshwater environments as well as coastal wetlands.It grows in water that is slightly brackish.This plant will adapt and survive when the coastal area is inundated due to sea level rise.There are several possible advantages to growing big swamp taro and adding it to livestock's and people's meals, including: • Enhanced food security by reducing our dependency on only major crops for food • Offering a wider variety of solutions to address climate change • Maximizing the use of available land by growing crops on marginal or unsuitable soils for other important crops • Encouraging local communities to have access to healthy nutrition.
• Increasing income-generating opportunities for small and medium-sized farmers For ensuring sustainable food futures, the cultivation of Dalugha must aim to increase yields through better technology, water, seed and fertilizer; and to reduce losses through better pest and disease management; storage condition and supply chain quality.Beside cultivation, post-harvest-processing is also important.Until now, Dalugha taro product in the market is only its corm and crackers.Processing technology needs to be introduced with local people in Sangihe.Potential benefits of Dalugha cultivation and processing should be promoted to the locals especially to diversify income generating opportunities for local farmers.

Figure 5 .
Figure 5. Dalugha corms sold in local market.Localgovernment has a food diversification program, Program Two Days No Rice.The local are encouraged to non-rice food.In 1 (one) week two days are set, namely on Tuesday and Friday to not consume rice and processed food ingredients containing rice and wheat flour, replaced by consuming local food ingredients as a source of carbohydrates, namely sago, cassava, sweet potatoes, bananas, corn, taro, giant taro Dalugha or other tubers.By doing this local dependency on rice will be reduced and food security in the island can be maintained.Interestingly, Dalugha is served at wedding party or other functions in Tamako District.This was done to introduce Dalugha to younger generation, to elevate the value of Dalugha and to preserve the local tradition.Dalugha is an underutilized crop that locals value as an important alternative staple food.It is high in starch, which is a great source of energy.When rice intensification program in the 80s introduced in Tamako area, Dalugha plantation was converted into paddy field.It was not a successful initiative in Tamako as local prefer to cultivate Dalugha than rice.Now, no paddy fields-Taro has been planted to replace paddy rice.For them, Dalugha is a local crop, native to Tamako District and it has a long history of facing food crises.