KINGDOM of CAMBODIA Nation Religion King ECOSYSTEM

KINGDOM OF CAMBODIA Nation Religion King 

ECOSYSTEM MANAGEMENT PLAN FOR THE INVASIVE ALIEN PLANT SPECIES, MIMOSA PIGRA, AT STUNG SEN CORE AREA, TONLE SAP BIOSPHERE RESERVE, CAMBODIA

Report Submitted to CABI under the UNEP/GEF Project: Removing Barriers to Invasive Species Management in Production and Protection Forests in SE Asia-FORIS Cambodia Project (UNEP/GEF Project No. 0515)

December 2013

TABLE OF CONTENTS

List of Figures ...... ii List of Tables ...... ii I. Introduction and Purpose ...... 1 II. Methodology and Approach Followed to Develop this Management Plan ...... 2 III. Details of Pilots Site ...... 3 3.1. Locality ...... 3 3.2. Flora ...... 4 3.3. Fauna ...... 4 3.3.1. Mammal ...... 4 3.3.2. Birds ...... 4 3.3.3. Fish ...... 5 3.4. Land Use ...... 5 3.5. History of Invasion ...... 6 IV. Details of Target Invasive Species ...... 6 4.1. Description ...... 6 4.2. Distribution and Spread of Mimosa pigra in Cambodia ...... 7 4.3. Invasiveness Elsewhere ...... 7 4.4. Impacts ...... 8 4.4.1. Biodiversity and Environmental ...... 8 4.4.2. Socio-economic ...... 8 4.4.3. Health ...... 9 V. Invasive Species Control and Landscape Management Activities Conducted To date in Cambodia ...... 9 5.1. Manual Control ...... 10 5.2. Chemical Control ...... 10 5.3. Biological Control ...... 10 5.4. Restoration ...... 11 VI. Proposed Management Activities ...... 11 6.1. Awareness Raising ...... 11 6.2. Experimental Trial on Mimosa pigra at Stung Sen Core Area ...... 11 6.2.1. Purpose of the Trial ...... 11 6.2.2. Material and Methods ...... 12 6.3. Gantt Chart of Activities against Duration of the Experiment ...... 15 6.3.1. Gantt Chart of Pilot Activities ...... 15 6.3.2. Gantt Chart of Proposed Management Activities ...... 16 6.4. Stakeholders Involvement ...... 19

REFERENCES ...... 22

List of Figures

Figure 1: Map showing the Location of Stung Sen Core Area ...... 3 Figure 2: Different land use classes for each zone ...... 5 Figure 3: The Experimental Design Tree showing the combined effects of manual, herbicide and restoration control ...... 13 Figure 4: Plot Design ...... 13

List of Tables

Table 1: Ten native species and exotic plant species for the purpose of monitoring and biodiversity change ...... 13 Table 2: Gantt Chart of Pilot Activities ...... 14 Table 3: Gantt Chart of Proposed Management Activities ...... 15 Table 4: Stakeholders’ roles/ Responsibilities ...... 18

I. INTRODUCTION AND PURPOSE

Invasive Alien Species (IAS) are non-indigenous plants, animals and microorganisms that have been deliberately or accidentally introduced to new areas beyond their native ranges, and which then spread impacting negatively on biodiversity and economic development. IAS can alter vital ecosystem processes such as fire, hydrology and nutrient cycling; kill, suppress, compete with or displace native species and communities; or alter gene pools through hybridization (Chornesky & Randall 2003). The spread of IAS including plant species is now recognized as one of the greatest threats to habitats, ecosystem functioning and economic development on our planet. IAS cause enormous damage to crop and pasture production and natural ecosystems. Direct and indirect impacts are increasing and damage to natural systems which are often irreversible; the impacts are exacerbated by global climate change, threatening the life supporting systems on our planet. Article 8(h) of the CBD calls on Parties to “as far as possible and as appropriate: Prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species”. At the sixth Conference of the Parties (COP 6), Parties adopted guiding principles and a programme of work for the implementation of Article 8(h) (Decision VI/23; CBD 2002). This decision recognized IAS as one of the primary threats to biodiversity in the world and urged bilateral donors and other funding sources to make funding for development and implementation of IAS strategies and actions in geographically and evolutionarily isolated ecosystems an urgent priority (Target 9 of the 2020 CBD Aichi Targets). IAS are common in Cambodia, impacting on crop and pasture production, human and animal health, water resources, biodiversity and economic development in general. One of these species, mimosa (Mimosa pigra L.) is one of the most abundant and widespread IAS in Cambodia and has invaded many Protected Areas, including the Stung Sen Core Area of the Tonle Sap Biosphere Reserve. Mimosa, Mimosa pigra L., is a thorny invasive plant that is originally native to Mexico, and Central and South America and has now spread into all tropical regions. The common name of this species is different among countries (Heard et al., 2009). The mature plant is 6 meters tall and can harm native plants, animals, and wildlife as well as human activities, by forming dense impenetrable bush and spreading quickly in floodplains (Marko, 1999). Each mimosa plant can produce 220, 000 seeds per year (Lonsdale, 1992 cited by Marko, 1999). Mimosa has high reproduction rate and the ability to adapt to many wetland habitats, such as canals, ponds, lakes, streams, rivers, reservoirs, and along the road side. It is also one of the worst invasive species in Cambodia and other countries because of its quick invasion and impact on agriculture, fisheries production, and economy (Kosal, 2004; Samoth, 2004; Beilfuss, 2007).

As a result, Cambodia has recognized the urgent need to address the problems of IAS, and has teamed up with CABI to implement a Regional Project entitled “Removing Barriers to Invasive Species Management In Production and Protection Forests in Southeast Asia” involving three other countries: Indonesia, Philippines and Vietnam. The project is funded by the Global Environment Facility (GEF) through the United Nations Environment Programme (UNEP). The overall goal is to conserve globally important forests, species and genetic diversity within SE Asia. The project objective is: “To manage SE Asian forests and biodiversity sustainably by reducing negative environmental, economic and human health consequences of invasive alien species”. The project will contribute to this goal through its purpose of removing the barriers to effective prevention and management of invasive alien plants in the four pilot countries (Cambodia, Indonesia, Philippines and Vietnam). The overall structure of the project comprises five technical and two project management components addressing:  Component 1: national policy and institutional frameworks;  Component 2: regional cooperation;  Component 3: national capacity building and institutional support;  Component 4: national pilots on the prevention, control and management of priority forest IAS;  Component 5: national information and awareness programmes;  Component 6: monitoring and evaluation; and  Component 7: project management.

The purpose of this Ecosystem Management Plan is to manage and contain M. pigra in the Stung Sen Core Area in order to protect native species from the impact of this alien plant species, and to help to secure the livelihoods of local communities in the area.

II. METHODOLOGY AND APPROACH FOLLOWED TO DEVELOP THIS MANAGEMENT PLAN

The development of this Ecosystem Management Plan (EMP) is based on the guidelines prepared by Mauremooto and Howard (2006). In addition, the draft pilot site management plans of Uganda, Ethiopia, and Ghana were used for guidance. National and international literatures on invasive plants were also used. The draft management document was prepared by the National Task Team in cooperation with the National Project Coordinator (NPC); and then sent to the Project Management Committee (PMC) and Project Management Unit (PMU) for comments. The draft document was also discussed by the Pilot Site Management Committee, and presented in the Sub-NSC meeting. After the comments were received, the document was edited by an ad hoc stakeholder group.

III. DETAILS OF PILOT SITE

3.1. LOCALITY Stung Sen Core Area, comprising an area of 6,355 ha, was created under the Royal Degree on the establishment of Tonle Sap Biosphere Reserve (TSBR) dated 10 April 2001 in order to protect unique evergreen riverine forests and associated vegetation assemblages (Royal Degree, 2001). Stung Sen is the buffer zone of the three core zones within the TSBR comprising the most important inland wetland in Southeast Asia, both for biodiversity conservation and livelihoods based on harvesting of aquatic resources (MoE, 2007). Stung Sen Core Area is situated in the southeastern end of Tonle Sap Lake, in Phat Sanday Commune, Kampong Svay District, Kampong Thom Province, Cambodia, which is part of the Tonle Sap floodplain system with elevation between 0 and 10 m (Mam et al, 2011). This is a floating village where most of householders are living on floating houses. More than 70% of the people in this commune fish for a living.

Stung Sen Core Area

Figure 1: Map showing the Kingdom of Cambodia and the location of Stung Sen Core Area

3.2. FLORA The flooded forest of the Tonle Sap is vital for seasonal breeding, nursery grounds and forage areas for fish that migrate to the Mekong River. With shrublands, stunted swamp forests, gallery forest and submerged and floating aquatic vegetation, the flooded forest provides many important benefits for both people and animals. Scientists have recorded about 200 plant species; the flora as a whole is distinct from that of other Mekong wetlands, especially with regard to woody species. The flooded forests extended over more than 1 million hectares originally, 614,000 hectares in the 1960s, and 362,000 hectares in 1991. Current estimates put the area of flooded forest at less than 240,000 hectares. Trees are cut to make fishing gear, including drift fences and fish traps (MoE, 2007). More than a dozen exotic plant species have become established in the Tonle Sap floodplain (CNMC et al., 1998; Oertzen and Smith, 2001). These include two grass species: Brachiaria mutica and Echinochloa stagnina that were introduced from Africa as high quality species for grazing, and have subsequently become dominant in many parts of the floodplain. Other noxious invasive species are water hyacinth (Eichhornia crassipes) and giant mimosa (Mimosa pigra), both of which are from Central and South America. Water hyacinth occurs along waterways with slow-moving water, and in pools and ditches, and to a certain extent. It is regarded as useful by local communities as it may be used as pig fodder and in fish attracting devices (samras). However, as water hyacinth forms dense mats it tends to de-oxygenate waters, and subsequently reduces water quality and fish production, especially in smaller bodies of water. Giant mimosa invades fallow fields and cleared and burnt swamp forest and scrubland areas, forming dense, impenetrable thickets that are very difficult to eradicate. It is also of little value to wildlife, although its effects on fisheries have not been well documented. At Tonle Sap it has recently become established along the length of the Tonle Sap River, scattered along the lake shores from Siem Reap to Snoc Trou, and in the Prek Toal Biosphere Reserve Core Area (CNMC et al., 1998).

3.3. FAUNA

3.3.1. Mammals Mammal diversity of Stung Sen Core Area is not high with about 46 species of mammals having been recorded in the Tonle Sap (MoE, 2007). Three species of primate occur in the Stung Sen Core Areas, Slow Loris (Nycticebus coucang), Long-tailed Macaque (Macaca fascicularis) and Silvered Langur (Semnopithicus cristatus). Their presence has been confirmed by local communities and by Goes and Hong (2002). Two species of otters occur in this area, the Smooth Otter (Lutra perspicillata) and Hairy-nosed Otter (Lutra sumatrana). Only 10 species of mammals were confirmed as being present in the Stung Sen Core Area during interviews and a desk study for the baseline data collection in early 2013.

3.3.2. Birds Birds have been more extensively studied than any other group, with over 225 species, 17 of which are IUCN Red-Listed (WCS, 2009). These species include Spot-billed Pelicans, Lesser Adjutant, Greater Adjutant, Asian Open bills, and Black Necked Stork.

Globally significant colonies of Greater and Lesser Adjutants, Spot-billed Pelican, Painted and Milky Storks, Black-headed Ibis, Darter and Indian Cormorant breed in seasonally inundated swamp forest in the Stung Sen Core Area. The area infested with M. pigra is very thickly invaded and has very few birds and other animals. According to the communities, fewer birds were observed in areas that are infested with mimosa compared to areas without mimosa. The Stung Sen Core Area seemed to be visited by endangered and critical endangered water birds more in the wet than in the dry season.

3.3.3. Fish The productivity of the Tonle Sap fisheries is one of world's highest. This is generally attributed to the flooded forest which not only provides shelter and protection for fish but also plays an important role in the production of biological resources which interact as a giant food chain ( MoE, 2007). Fish numbers are considered to be decreasing from year to year because of an increasing human population, market demand, and illegal fishing. Most fishermen use illegal fishing equipment, including small mesh sizes, electro fishing, and pumping out water with engine pumps from natural ponds and streams in order to catch fish. Alternatively, habitat clearing and conversion for agricultures is a significant conservation issue, with increased fertilizer use and runoff into the lake adversely affecting fish and local people. People have mentioned that sedimentation is making the water shallow, and the flooded forest is becoming less than before. This means that the fish can’t find suitable habitats for shelter and breeding. 3.4. LAND USE Based on a recent socio-economic survey in the Tonle Sap Lake, Keskinen (2003) revealed that in terms of land use, the area can be divided into four major zones:  Water bodies and flooded shrub – Zone 1  Grassland and paddy fields – Zone 2  Paddy fields – Zone 3 and 4  Village gardens and settlements – Zone 5

These four major land use zones are easily distinguishable from each other (Figure

2).

Figure 2: Different land use classes for each zone (JICA 1999). It is interesting to note that the area of flooded forest is only 1.3% of the total area (JICA, 1999). However, the total area of flooded shrub is more than 40% in Zone 1 and also almost one third of the total land area. The area of floating rice fields appears to be extremely small in every zone, and is slightly higher in the zones closer to the lake.

3.5. HISTORY OF M. PIGRA INVASION Mimosa pigra is an introduced/exotic plant that has invaded Cambodia for decades, probably from neighboring countries, where it is also considered to be a weed. M. pigra was introduced to Thailand from Indonesia in 1947 for controlling riverbank erosion, covering tobacco crops, and producing natural fertilizer (Napompeth, 1983; Wara- Aswapati, 1983). It was found in northern Thailand in 1949 and spread into Vietnam probably before 1970 (Thi et al., 2004), and it invaded Long An province by 1979 (Triet et al., 2004). This weed may have been introduced to Cambodia in the 1980s (Vanna & Nang, 2003) in the Tonle Sap Great Lake and has invaded many wetlands in the country by 1990s, especially along the Mekong River, Tonle Sap River, around Tonle Sap Great Lake, and many wetlands along the Cambodian Mekong River basin (Samouth, 2004). Now it occupies thousands of hectares of flooded grasslands and abandoned fields. It is estimated that M.pigra could potentially invaded at least 2100 km2, or 20% of the maximum flooding zone (Samouth, 2004).

IV. DETAILS OF TARGET INVASIVE SPECIES

4.1. DESCRIPTION As a young plant mimosa consists of a single prickly stem, often as a ground creeper or prostrate form. Mature mimosa tends to be a branched shrub with rose-like thorns. The plant can reach a height of 3-6 m with a branching tap root extending 1−2 m deep. Leaves are green, feathery and fern-like, with the central leaf stalk being prickly and 20−25 cm long. Each leaf contains up to 16 opposite segments, each segment 5 cm long and divided into pairs of leaflets which fold up at nightfall or when touched or injured. The flowers are round, fluffy, pink or mauve balls 1−2 cm across. Each flower head produces a cluster of 1−30 seed pods which are 3−8 cm long and covered with dense hairs. The pods turn brown when mature and break into segments, which fall away from the pod leaving a skeletal outline. Each segment contains an oblong shaped seed 4−5 mm long and 2 mm wide. Mimosa typically germinates as flood waters recede. Plants mature quickly and can set seed in their first year of growth. The first flowers tend to appear 6−8 months after germination. Flowers are bee-pollinated or possibly wind-pollinated. Seedlings occur approximately 3−6 weeks after the flower bud is formed. The one seeded, hairy segment of mimosa pods are easily spread by humans, animals, and water. Segments may become attached to people’s hair, shoes, and clothing. The segments stick to the fur of animals and can pass unharmed through their digestive tract. Seeds pods are buoyant, and are readily dispersed by flood waters and water currents (ICBD/GDANCP, 2013).

CLASSIFICATION The taxonomy of Mimosa pigra L. is detailed as following: Kingdom: Plantae Sub-kingdom: Viridaeplantae Division: Tracheophyta Class: Magnoliopsida Order: Fabales Family: Fabaceae Genus: Mimosa Species: M. pigra L.

4.2. DISTRIBUTION AND SPREAD OF MIMOSA PIGRA IN CAMBODIA M.pigra generally invades wet and humid places such as floodplains, seasonal wetlands, canals, and riparian vegetation. It will also grow along roadsides and other areas with sufficient soil moisture. It is one of the worst environmental weeds of the Mekong River basin (Storrs et al, 2001). This thorny shrub reproduces via buoyant seed pods that can spread long distances in flood waters and has the potential to spread through grasslands, floodplain ecosystems and pastures, converting them into unproductive scrubland. It is a serious agricultural weed in the Lower Mekong Basin often establishing in areas along streams and canals and then invading adjacent rice fields. In heavily infested areas, few native plants can grow under the mimosa canopy. Mimosa pigra is now present in many wetlands in some provinces such as Stung Treng, Kratie, Kampong Cham, Kandal, Kampong Chhnang, Kampong Thom, Pursat, Battambang, Siem Reap, Prey Veng, Svay Rieng, Takeo, and Kampong Speu (Samont, 2004). Additionally, it has been found recently in some wetlands in the provinces of Bantey Meanchey, Odor Meanchey, Preh Vihear, Ratanakiri, and Mondul Kiri (Triet et al., 2013).

4.3. INVASIVENESS ELSEWHERE Developing and transitional countries undergoing rapid economic development will face growing problems with biological invasions because international commerce will bring new invaders (Weber & Li, 2008). Like most natural ecosystems across Asia, the wetlands in the Lower Mekong Basin are under threat from various human activities and from IAS. Currently, major pathways for introduction of IAS in the region include aquaculture, horticultural and ornamental fish trades. Dams, urbanization, expansion of agriculture, trans-boundary road development and other rapid development activities are exacerbating the spread of IAS (Miththapala, 2007).

Mimosa pigra is now widespread throughout the tropics. Because of the sensitivity of the leaves to human touch it was probably taken to many parts of the world as a curiosity plant. For example, Ridley (1930) describes the movement of M. pudica around the Pacific as early as the 16th century by Jesuit missionaries, via their settlements in Manilla, and the same may be true of M. pigra, since there are early records of the plant in the Philippines (Robert, 1982). It has been present in Africa for quite some time but has only become problematic in the recent past. The earliest records for various countries outside its native range are Egypt in 1829, India in 1867 or before, New Guinea in 1960, Singapore in 1965, Sumatra in 1975, Thailand in 1947, Java in 1844, Uganda in 1862, Tanzania in 1929, Kenya in 1945, Nigeria in 1822, Senegal in 1824, Sierra Leone in 1891, French Guinea in approximately 1898, and Ghana in about 1925 (see Lonsdale et al., 1989 for more details). It has been recorded as being particularly problematic in Cambodia, Ghana, Indonesia, Malaysia, Myanmar, Sri Lanka, Thailand, Uganda, Mozambique, Vietnam, and Zambia, and others. 4.4. IMPACTS 4.4.1. Biodiversity and Environmental Plant invasion presents a serious threat to biodiversity management and conservation in many parts of the world (Grice, 2006). Mimosa pigra is one of the worst environmental weeds. Invasion of mimosa has resulted in the loss of feeding and resting habitats of migratory fish, birds and other mammals. In heavily infested areas, few native plants can grow under the mimosa canopy. Aquatic weeds reduce crop yields and decrease water supply by degrading water catchment areas and freshwater ecosystems. Mimosa infested areas are inaccessible to animals and people, and interferes with stock watering, irrigation and recreational use of waterways. Mimosa has demonstrated the capacity to form vast monocultures, particularly in floodplain areas which are highly valued from environmental, cultural and economic perspectives (Davies et al., 2006). The presence of mimosa has caused a decline in both the population size and number of species of plants and animals. In Tonle Sap Lake, mimosa was first seen in the 1990s and by 2000, it had invaded the whole area, especially where the flooded forest had been cleared. Samouth (2004) reported some impacts on biodiversity and the environment including:  several white fish species have disappeared  fish catch has declined  displacement of local plant species  degraded fish, wildlife and bird habitats  disturbance of aquatic life  trapping sediment.

4.4.2. Socio-economic Damage from aquatic invasive alien species impacts is not restricted to ecosystems; they also affect human economic interests, as many people depend on inland water ecosystems for their livelihoods. Samouth (2004) reported that local people obtain food, basic household commodities, arable land, water and fuel wood from Boeung Thom

8 wetland. Every year farmers spend a lot of money on mimosa clearance and they get less income from the agricultural product. It is difficult for farmers to find food and pasture for their animals and also difficult to access the wetlands for food and wetland product collection. Some farmers have left their land to find other jobs in the province or cities, as building workers, garment factory workers, taxi operators, and so on. Discussions with stakeholders indicated that the major threats of mimosa to wetlands was the formation of mono-species stands that impact negatively on aquatic resources, agriculture, and family economics. The impacts raised by stakeholders included loss of money and time for agricultural land preparation, and difficulty to access wetlands for fishing and food collection. In addition, M.pigra reduces crop yields and decrease water supply by degrading water catchment areas and freshwater ecosystems. The infested areas are inaccessible to animals and people, and interfere with stock watering, irrigation and recreational use of waterways. 4.4.3. Health IAS can impact the health of humans and other species. Food and water shortages, caused by IAS, can have negative consequences for all living organisms, but are particularly problematic in the developing world (McNeely et al., 2001). When certain pesticides are used to eradicate or control IAS, people and the ecosystems on which they depend can often be placed at risk (Parker, 2001). Mimosa pigra invades fallow fields and cleared and burnt swamp forest and scrubland areas, forming dense, impenetrable thickets. Thorns damage eyes and skin of cattle. No major human health problems have been reported to date.

V. INVASIVE SPECIES CONTROL AND LANDSCAPE MANAGEMENT ACTIVITIES CONDUCTED TO DATE IN CAMBODIA

Hand clearance was the first method used to deal with M. pigra on agricultural lands. This involved cutting of trees, uprooting of stumps and seedlings. It is very labor intensive and thus expensive and only cost effective on a small scale. Another control technique applied by farmers is burning the tree – but both hand clearing and burning leave a significant seed store in the soil and the plants geminate with the next rain seasons and/or re-infest the cleared areas. The present use of the plant as fuel wood will, to some extent, control and minimize the rapid expansion of the plants. This could be observed in the provinces of Kandal, Kampong Chhnang, Prey Veng, Svay Rieng, and Takeo where there is a shortage of fuel wood for supporting daily livelihood. It is an assumption but that other factors may also be playing a role. Recent research has shown that mimosa can be processed to produce charcoal and a useful gas fuel, and that the gas can be converted to electricity using commercially available system components (Presnell, 2002). At great expense, commercial farms use bulldozers to clear mimosa infestations. In other areas such as on small farms, roadsides, and irrigation and drainage canals uprooting, using human labor, is often employed, followed by burning of the removed foliage. More than 40% of rice farmers surveyed in Kandal Province in the year 2000

9 indicated that Mimosa was a “serious” problem, 4x more than in 1995. Overall, the farmers ranked Mimosa as the most significant problem affecting rice farming, “ahead of pests, rodents, and drought problems” (Chamroeun et al., 2001.). Survey data indicated that Mimosa imposed a significant cost on Kandal’s farmers in 2000, especially on those farming along the Mekong River. On average, Mimosa removal costs represented about 5-10% of the total farming input costs (Chamroeun et al., 2001.). These costs had a major impact on the farmers’ net revenues, representing a loss of close to 50% of net revenues in some cases. To cope with the infestation of M.pigra in their agricultural lands, people of the Stung Sen Core Area have used simple control options to combat this weed: 5.1. MANUAL CONTROL Manual control is the physical removal of the target species by hand-pulling or use of hand tools such as hoes, spades, saws or similar. The process requires a long-term investment of human resources. Due to the long flooding season, local communities can cultivate only from February to July in alluvial soil areas along the tributary of the Tonle Sap Lake. Just after harvesting time, mimosa starts to grow and quickly increases in biomass. To enable sowing of the next crop, local communities have to cut mimosa plants before flooding in order to “drown” regrowth and seedlings. First year plants may be inundated and die during the seasonal flooding while older plants can survive. These older plants hinder ploughing during the next season and the weed regrows together with the planted crop. Over several years, mimosa can completely prevent farming. Community experience with mimosa management in the Tonle Sap showed that stem cutting, fire and combined cutting and fire were not effective in managing the weed because these methods do not kill established plants, they merely coppice, and have no impact on the large seed bank – seed germination is triggered by fires. Stem cutting is also labor intensive and requires equipment. 5.2. CHEMICAL CONTROL Chemical control is the use of herbicides to control plants and pesticides to control undesirable pests .Herbicides can be quite costly and typically requires repeat applications to control emerging seedlings until the seed bank has been depleted. Although herbicides, especially non-selective herbicides, are not encouraged for use in protected areas such as Stung Sen Core Area, they are an effective control method when mimosa spreads over a large area and other control methods are difficult to implement. A few people living in the Stung Sen Area use herbicides, especially foliar spraying of glyphosate, to kill Mimosa in their croplands during the dry season. This method is more effective than manual control. 5.3. BIOLOGICAL CONTROL Biological control is the introduction of a specific predator, parasite or pathogen that will attack the target IAS. This process will not result in the eradication of the target species but reduces the abundance/distribution of the IAS to acceptable levels. The initial costs associated with research and development may be high, but the long-term costs once

10 applied are low and relatively little maintenance is required. No biological control programme have ever been implemented in Cambodia. However, a survey of insects (natural enemies) associated with M. pigra in the Tonle Sap Great Lake and surrounding provinces was conducted in March 2013. This study revealed that there are a number of natural enemies associated with Mimosa in Cambodia, including a number of biocontrol agents that have moved into Cambodia from Vietnam and Thailand. 5.4. RESTORATION Restoration is the process of re-establishing natural populations and ecosystem functions. In theory, this increases the ecosystem’s resistance to future invasions (Mueller- Dombois, 1981). According to Mr. Tem Sokhtearng, site manager of the Stung Sen Core Area, reported that some parts of the Stung Sen Core Area were restored in these recent years because the flooded forest in those areas had been burnt during the dry season. The plant species used for the restoration purpose is Rang Teuk (Barringtonia acutangula) which is dominant and native to that area. Other possible plant species for restoring the flooded forest in the area are Phtul (Diospyros cambodiana), Sandann (Garcinia cochinchinensis), Chhkeng (Mallotus anisopodus) and morning glory (Ipomoea aquatica). These species are native can be found locally and the morning glory is used by some local communities to suppress seedling of mimosa in their agricultural land.

VI. PROPOSED MANAGEMENT ACTIVITIES To cope with the spread of mimosa, relevant institutions in Cambodia should focus on the most effective measures for immediate control and long term prevention of its spread. In terms of this UNEP/GEF Project the intention is to develop best management practices for the control of M. pigra. Activities to be undertaken over the next three years have been grouped as follows:

6.1. AWARENESS RAISING Capacity building and awareness creation activities have been developed to target different stakeholders about the potential problems associated with M. pigra and the measures that need to be taken to manage Mimosa. Awareness is being generated through the use of mass media, presentations, field days, local community meetings, weed awareness days, and workshops.

6.2. EXPERIMENTAL TRIAL ON MIMOSA PIGRA AT STUNG SEN CORE AREA

6.2.1. Purpose of the Trial The general aim of this research is to evaluate two (2) control methods against the target species, Mimosa pigra, in the Stung Sen National Pilot Site. The impact of each method on the target species and on biodiversity will be determined. The following questions will be addressed: 1. Has there been a reduction in the abundance alien plant species after control? 2. Has there been a positive response from the native plants after control?

3. Have other alien plants invaded the site after control of the target species, or have existing alien plants increased in cover or density? 4. What are the costs and benefits associated with the management strategy?

6.2.2. Materials and Methods  Description of treatments The experiment was designed in such as way so as to compare two mimosa control methodologies (manual vs manual plus herbicide) followed by no revegetation (natural regeneration), revegetation by a native tree species, and revegetation by the same tree species and a native ground cover. There were control plots where no management activities were undertaken for comparative purposes (see Figure 3 for the experimental design tree). The various treatments were as follows: Treatment 1A (T1A): Manual control in a 10 x 5m plot whereby mimosa stems are cut just above ground level using bush knives. All cut stems/branches removed from the plot. Treatment 1B (T1B): As in T1A followed by revegetation using Rang Teuk (Barringtonia acutangula). Treatment 1C (T1C): As in T1B but including morning glory (Ipomoea aquatica) in revegetation. Treatment 2A (T2A): Combination of manual and herbicide control in a 10 x 5m plot. The Mimosa plant will be cut c.a 10 cm above ground level using bush knives followed by the immediate application of a 10% herbicide solution (Glyphosate) to the cut stump using a hand sprayer. All cut stems/branches removed from the plot. Treatment 2B (T2B): As in T2A followed by revegetation using Rang Teuk (Barringtonia acutangula) Treatment 2C (T2C): As in T2B but including morning glory (Ipomoea aquatica) in revegetation.

Figure 3: The experimental design tree showing the combined effects of manual, herbicide and restoration controls.

 Experimental Research Design Experimental Sites The trials will be conducted in one site along the river inside the Stung Sen Core Area, with three replicates as shown in Figure 3. The selected area is at Toul Neang Say village: UTM 48P 0445746/1387892. The site was selected based on the presence of large monocultures of mimosa, all with similarly-sized trees at similar densities.

Plot Design The plots will be arranged in blocks that have similar mimosa density. Each block consists of 3 plots (10m x 15m) and each plot consists of 3 sub-plots (5m x 10m) on which each of the treatments will be randomly assigned (see Figure 4 below for the plot design). All together, the experiment employed 9 plots in 3 blocks in one experimental site.

Control T2 T1

T2A T2C T2B T1C T1A T1B

Figure 4: Plot Design

 Monitoring

Monitoring activities All costs associated with various management strategies will be recorded. The specifics include the costs of paid labour, materials, contractors, as well as office costs related to management activities. Additionally, the number of days spent monitoring is also a very useful measure for future reference and planning.

Data Collection In each sub-plot, baseline information will be collected from ten 1 m2 quadrats prior to the initiation of any management activities and at regular intervals subsequent to that to measure any changes in biodiversity. In each sub-plot the following parameters will be measured and recorded:  mimosa stumps density (number of stumps per square metre),  plant height,  number and height of seedlings,  number of new shoots and height of new shoots,  plant species composition including the monitoring species (see Table 1),  photo points  observational data These parameters are measured and recorded before the treatments, one month, two months, four months and six months after treatment.

Plant Species Monitoring Ten native and exotic plant species present in the experimental plots will be monitored in terms of the biodiversity assessments.

Table 1: Ten native and exotic plant species which will be monitored during the experiment

Species Names No Scientific Name Khmer Name 1 Barringtonia acutangula Rang Teuk 2 Diospyros cambodiana Phtul 3 Garcinia cochinchinensis Sandann 4 Mallotus anisopodus Chhkeng 5 Breynia vitis-idaea Phnek Preap 6 Croton canidatus Brobuoy 7 Morinda tomentosa Nhorprey 8 Cardiospermum halicacabum Peng Pohsrom 9 Passiflora foetida Savmao prey 10 Merremia emarginata Vor Ta oeuk

Equipment and Herbicide Needed

 Caliper  Pen, Pencil, clear plastic bag...  Tap meter  Mask  Glove  Hand Sprayer  Boot  GPS and External Hard Disk  Bush knife  Camera and Monopod  Spade  Plant Book ( Madame Dyphon Book)  Hand saw / pruning scissors  Water pipe ( Quadrat tool)  Permanent marker  Herbicide ( Metsulfuron / glyphosate)  Board for sighter ( photo point)  String  Billboard indicating the Pilot Site.  First Aid Kit

6.3. GANTT CHART OF ACTIVITIES AGAINST DURATION OF THE EXPERIMENT 6.3.1. Gantt Chart of Plot Activities

Table 2: Gantt Chart of Pilot Activities

Activities of Integrated Weed Management PY 2 (2013) PY 3 ( 2014) PY 4 (2015) No Responsible Person Practice Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 NPC, PMC, and 1 Selection of demonstration site Project Technical Advisor Design and print billboard showing the pilot site of 2 NPC & F.Coordinator the Project. Buy all equipment or materials need for the field 3 NPC & F.Coordinator work Experimental trial practice Plot demarcation, stump cutting and removing

M.pigra out where necessary Herbicide spot spraying of the selected plot NPC, Task Team and 4 Planting of selected tree species in the Field coordinator

selected plot Pre-treatment data collection Regular monitoring and post treatment data

collection

5 Data processing and report writing Field coordinator

6.3.2. Gantt Chart of Proposed Management Activities

Table 3: Gantt Chart of Proposed Management Activities Responsible PY 2 (2013) PY 3 ( 2014) PY 4 (2015) No Activities Objectives Expected Output Indicators Body (ies) Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 1 Survey of Insects on Mimosa To identify natural List of natural Survey report was National pigra in the Tonle Sap Great enemies associated with enemies associated submitted in May consultant Lake and the surrounding M. pigra in Cambodia with M. pigra in 2013 provinces Cambodia.

2 Selection of To identify Identification of Experimental plots Field demonstration/experimental demonstration plots for experimental plots approved by the coordinator; plots at the National Pilot trials. Project Technical Project Site Advisor Management Committee; Project Technical Advisor. 3 Identification of target plant To identify 10 target Ten target plant Ten target plant Field species at the plant species for pre- and species identified. species were coordinator; demonstration sites for post implementation reported and National Project biodiversity monitoring monitoring. documented in Coordinator; early July 2013. Project Technical Advisor 4 Study on distribution of To determine the A map showing the Map showing the BSc. Student Giant mimosa (Mimosa presence of M.pigra in distribution of distribution of from RUA. pigra) at Stung Sen Core Phat Sanday Commune mimosa in the mimosa in the Area study area. study area; Thesis

5 Collection of baseline data To determine socio- Socio-economic and Survey report National prior to intervention economic and other other impacts of Consultant management impacts of mimosa mimosa

6 Capacity building and To increase knowledge of Increased Participation and Field awareness creation on IAS stakeholders on impacts, knowledge of willingness of the coordinator; issues particularly M.pigra at prevention and stakeholders on communities to Project community and national management of mimosa. impacts, prevention mimosa Management level. and management. management. Committee; Local communities; and Local authority. 7 Integrated Weed To conduct experimental Practiced the Observational data Field Management Practice (Pilot trial at the experimental trial and experimental coordinator; Site Activity) demonstration sites. and engaged data were Task Team; stakeholders in this recorded and NPC; experiment. documented. Stakeholders. 8 Effectiveness of traditional To understand i) A MSc. thesis met The deliverables One MSc. methods in controlling and traditional methods that the RUPP were submitted in Student from managing mimosa pigra local people usually use requirement; A late 2014. RUPP (TBC) from the agricultural land to control and manage poster (A0) inside the Stung Sen Core mimosa in their garden indicating the Area. (MSc. Thesis Research) or agricultural lands.; ii) research finding; the effectiveness of and a manuscript those methods; and iii) for Article Journal. the cost of saving agricultural land from the invasion of mimosa. 9 Exploratory surveys and To more understand on i) A MSc. thesis met The deliverables One MSc. assessment of natural kind of natural insects the RUPP were submitted in Student from insects associated to the associating the mimosa; requirement; A late 2014. RUPP (TBC) mimosa pigra in Stung Sen ii) how effective of the poster (A0) Core Area. (MSc. Thesis insects in damaging the indicating the Research) plant species; and kind of research finding; insect species should be and a manuscript recommended to do for Article Journal. mass rearing for the purpose of long term control. 17

10 Monitoring and Evaluation To monitor and evaluate Field visits by PMC, BTORs of the field NPC, PMC and of Management Programme the plan activities. Sub-NSC, NPC and visit were stakeholders ( Task Team Activity) stakeholders produced.

11 Report on pilot project to To document the best A technical report Progress Reports Task Team; NPC demonstrate the best practice of the on best practice and Best practice practice management ( Task management at pilot site management was management sent Team Activity) produced to CABI.

6.4. STAKEHOLDER INVOLVEMENT

During this management plan period, the stakeholders affected by the spread of M.pigra will be identified, contacted and involved in the management of M.pigra. It is important that an effective communication strategy on issues related to management of M.pigra and biodiversity conservation be developed to ensure public awareness and readiness to handle the invasiveness of M.pigra. The stakeholders where M.pigra exists on agricultural lands will be called upon from time to time to participate in the demonstration/ trials that will be established at the edge of the Stung Sen Core Area in order to enable them use the M.pigra management technologies developed and effective dissemination of the technologies to the masses. In order to ensure effective implementation of this management plan, various stakeholders need to have different roles and responsibilities. The table 4 shows various stakeholders and identified roles and responsibilities.

Table 4: Stakeholders' roles/responsibilities Stakeholders Roles /Responsibilities Ministry of Environment Responsible government institutions for environmental concerns (MoE) in general General Department of - Overall coordination and technical inputs for development of Administration for related document and work programme on M.pigra in Nature Conservation and Cambodia. Protection (GDANCP) - Monitor progress of the Project activities. (MoE) - Information dissemination - Provide trainings. Provincial Department of - Overall coordination at site level, Environment (Kampong - Assist in administration inputs for implementation of work Thom) and the Stung Sen programme on M.pigra management at site level, Ranger Station - Participate in the experimental trial activity at the field site. - Mobilize communities for awareness creation on invasive species particularly on mimosa. - Integrate the management of M.pigra in its management plan. - Participate in weeding during seedling emergence to protect its growth and regular control of the weed on roadsides and open areas.

District Forestry - Participate in the control and management of M.pigra Administration (FA) and infestation in both national pilot site and its designated areas. Fishery Administration - Providing technical advice and sharing information with the (FiA)/ (MAFF). Project implementers. - Extension services delivery on invasive species. - Participate in weeding during seedling emergence to protect its growth and regular control of the weed on roadsides and open areas.

Local Authorities and - Participate in the implementation and monitoring of work Community Entities programme on M.pigra management. - Mobilize communities for awareness creation on invasive species particularly on mimosa. - Integrate the management of M.pigra in their Local government plans.

Stakeholders Roles /Responsibilities - Implement approved control measures for invasive plants. - Participate in weeding during seedling emergence to protect its growth and regular control of the weed on roadsides and open areas. - Report new invasion species to the lead agencies. Local Community - Participate in the awareness raising programme on the IAS issues. - Participate in the control and management of the IAS ( M.pigra) infestation in their agricultural lands regularly. - Regular weeding during seedling emergence to protect its growth. - Regular control of the weed on roadsides and open areas. - Report new invasion species to the lead agencies. Universities (RUPP, RUA - Involved in biological research and training on IAS. and PUC) - Promote students to undertake research on the IAS issues at the national pilot site. - Integrate IAS training/research programme/module into its curriculum. - Information dissemination.

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