(Mimosaceae) in Peninsula Malaysia: 1980-2004

M. Asyraf1,2, M J. Crawley.1 and M. Mashhor2 1Division of Biology, Imperial College London, Silwood Park, Ascot, Berkshire, United Kingdom. 2School of Biological Sciences, Universiti Sains Malaysia, Minden, Penang, Malaysia. [email protected]

Abstract: Mimosa pigra L. (Mimosaceae), a noxious semi-aquatic woody plant and once considered to be an important invasive species in the early 1980s has now spread through out Peninsula Malaysia. This happened despite an effort to control the spread through the introduction of two biological control agents, Carmenta mimosa and Acanthoscelides puniceus between 1992 and 1994. To assess the present status of Mimosa spread, a survey was conducted in 2004, which covered six habitat types namely a construction site, roadside, riverbank, reservoir, plantation and forest reserve. A total of 53 from 80 sites visited have been recorded with Mimosa populations. Five habitat types were more prone to be invaded by Mimosa whilst forest reserves were found to be non-susceptible to Mimosa invasion. Three conclusions can be drawn from this survey; (1) Soil contaminated with Mimosa seeds used in construction industries is likely to be the main dispersal agent, (2) Mimosa infestation has never been dealt successfully at its earliest establishment phase, and (3) the invasion is no longer restricted to wetland habitat but has spread into various types of landscapes and terrestrial ecosystems.

Key words: Mimosa pigra, distribution, Peninsula Malaysia

Introduction

Mimosa pigra L., Fabaceae (henceforth Mimosa) is a fast spreading thorny shrub, growing frequently up to 4 m but occasionally to 5-6 m tall (Forno et al. 1989). With annual seed rain of c. 9000 seeds m-2 (Lonsdale 1992; Lonsdale et al. 1985), Mimosa infestation can easily spread through soil contaminated with it seeds. The introductions of Mimosa outside its native range have caused great concern as it become highly invasive and important weed of the tropics (Lonsdale, et al. 1985). Serious environmental threats associated with Mimosa invasion are including loss of important native flora (Braithwaite et al. 1989; Triet et al. 2004a) and fauna, (Lonsdale 1992), restricted of accessible water body both to human and livestock, safety problem, and reducing land value and its productivity (Heard et al. 2005; Marambe et al. 2001; Marambe, 2001; Miller and Pickering, 1983; Napompeth, 1983; Robert, 1982; Thamasara, 1982). Wetland ecosystems face a constant threat by Mimosa invasion, where it can forms dense and impenetrable monospecific stands (Lonsdale 1992) which affecting agricultural activity and conservation effort. Similar condition already faced by some Southeast Asia countries (e.g. Thailand, Vietnam and Cambodia) which bordering the Mekong River basin (Winotai et al. 1992; Samouth 2004; Son et al. 2004;). The earliest record of Mimosa in Peninsula Malaysia was in 1980 from a survey conducted by the Department of Agriculture (DOA) although farmers in the state of Kelantan claimed the species has spread as early as 1970s (Anwar and Sivapragasam, 1999). Its population in Kelantan was assumed to be originated from Thailand where propagules might have been brought across the border by man-related activities and/or by water along the Golok River (Anwar and Sivapragasam, 1999; Napompeth, 1983). Mimosa was gazetted as “an A2 pest” based on the 4th Schedule of the Agriculture Pest and Noxious Plants (Import/Export) Regulation in March 1982 (Mislamah et al. 1991) where it was considered as already introduced and spreading in Malaysia. This has been further confirmed by a DOA survey in 1991 which revealed ten of 11 states surveyed were recorded with Mimosa populations, compared to only three states in 1981 (Anwar and Sivapragasam, 1999; see also Chan et al. 1981 and Mansor, 1987). To control further spread of Mimosa, Malaysian

Proceedings of the 21st Asian Pacific Weed Science Society Conference (Editors: B. Marambe, U.R. Sangakkara, W.A.J.M. De Costa, and A.S.K. Abeysekara), 2-6 October 2007, Colombo, Sri Lanka. government through the Malaysian Agriculture and Research Development Institute (MARDI) has initiated collaboration on biological control program with neighbouring countries and CSIRO, Australia in the 1980s. As a result, two agents; Carmenta mimosa and Acanthoscelides puniceus were introduced between 1992 and 1994. After 24 years, Mimosa has been reclassified as weed of waste land (Othman and Abu- Hashim 2003) and less attention has been given to monitor its spread and impact. However, Mimosa invasion into wetland habitats remains a threat. Based on this, a general survey has been conducted from March to May 2004 with objectives to review current Mimosa infestation especially in Peninsula Malaysia and to monitor Mimosa population and its distribution especially in wetland habitats.

Materials and Methods

Mimosa populations were surveyed in all states within Peninsula Malaysia, divided geographically into four groups as follow; (a) northern states: Perlis, Kedah, Penang, (b) east coast: Kelantan, Terengganu and Pahang, (c) southern states: Johor, Negeri Sembilan and Melaka, and (d) west coast: Perak and Selangor. Six habitat types (Table 1) were determined prior to the survey. The survey was conducted in such way that every habitat type is represented in each geographical group. Survey was carried out by; (a) driving along the main trunk road (federal road) and for every 100 km, a 10 m x 10 m plot was established to asses the mimosa population wherever the geographical condition permitted (data for this is to be published elsewhere), (b) assessment of Mimosa population for wetland habitats type and forest reserve were carried out within the riparian zone and forest fringe, respectively.

Results and Discussion

The survey has shown that Mimosa has spread to all 13 states in Peninsula Malaysia (Figure 1). Generally infestations are recorded at more than 60% of the area surveyed in each habitat type. Results also suggested that construction sites, roadsides and riparian zones are highly susceptible to Mimosa. However, forest reserves were free of Mimosa (Table 1). Major infestation was marked in Figure 1, along with eight forest reserves where no record of Mimosa was made.

Table1: Major site surveyed recorded with Mimosa infestation.

Habitat Type No. of sites surveyed No. of sites with infestation % Construction site 20 15 75.0 Roadside 20 17 85.0 Riverbank 12 9 75.0 Reservoir 8 5 62.5 Plantation 10 7 70.0 Forest reserve 10 0 0.0 Total 80 53

Construction sites and roadsides Comparatively, roadside is more highly invasible by Mimosa than are other habitat types (Table 1). Soil contaminated with its seeds is most likely the source of propagule. The movement of seed banks is enhanced by transporting soil from one construction site to another (Benyasut and Pitt, 1992; Miller and Pickering, 1983). This may also explain its successful establishment along the East-West Highway. Since this highway is one of the main routes linking East and the West coast of Peninsula Malaysia, it is likely that Mimosa seeds

Proceedings of the 21st Asian Pacific Weed Science Society Conference (Editors: B. Marambe, U.R. Sangakkara, W.A.J.M. De Costa, and A.S.K. Abeysekara), 2-6 October 2007, Colombo, Sri Lanka. are being moved unintentionally, in greater distance. However, populations observed in developing zones with active construction projects are most probably only to survive during the construction period.

Figure1. Some of major infestation of Mimosa ( ) and forest reserves (only eight of ten forest reserves shown here) visited were without Mimosa ( ) during the survey

Riverbanks and reservoirs Wetland habitats especially river corridors, flood plains, lakes and reservoirs face extreme possibility of being invaded by Mimosa as also observed in other tropical countries (Samouth, 2004; Triet, et al. 2004b). Five reservoirs have been observed to be infested with Mimosa, namely Pedu (Kedah), Temenggor and Bukit Merah (Perak), Pergau (Kelantan) and Kenyir (Terengganu). Infestations in all these sites are likely due to soil containing Mimosa seeds brought into those areas during construction. The spread of its population however is limited to open flood plain and has not been observed within the forest edge bordering the dams. Newly constructed water canals and riverbanks used as soil dumping sites are also highly prone to Mimosa infestation, which conform to studies by Napompeth (1983) and Mansor (1987). The survey also revealed that waterways located in vicinity of newly developed roads and highways are likely to be infested with Mimosa. Although Mimosa infestation in reservoirs may has not reached an alarming state, as faced by other Southeast Asian countries, e.g. Cambodia (Samouth, 2004) and Vietnam (Triet et al. 2004b), preventing possible outbreak must be included as part of the management program.

Agricultural lands and forest reserves Plantations recorded with Mimosa were young oil-palm plantations and coconut orchards. Plantation areas under constant disturbance (e.g. weed management program) are relatively free of Mimosa. However, as the above crops are much stronger competitor in their later stage, Mimosa infestation is presumably negligible.

Proceedings of the 21st Asian Pacific Weed Science Society Conference (Editors: B. Marambe, U.R. Sangakkara, W.A.J.M. De Costa, and A.S.K. Abeysekara), 2-6 October 2007, Colombo, Sri Lanka. Intact forest areas are non-susceptible to Mimosa infestation. However, Mimosa might be able to establish at the forest edges due to large canopy opening and with substantial supply of propagules, although it is very unlikely to survive within the intact forest.

Conclusions

Generally the spread of Mimosa into many parts of Peninsula Malaysia is due to movement of soil with its seed from an infested areas to another as also reported in Australia (Miller, 1983) and Thailand (Napompeth, 1983). In addition, biological control program of Mimosa was most probably failed to materialise although scattered population of seed bruchids can be found especially in Penang and Selangor (personal observation, 2004). The reclassification of Mimosa as a common weed doesn’t reduce its potential of being invasive. As shown, Mimosa is capable to invade successfully into terrestrial ecosystem and no longer restricted to aquatic and semi-aquatic habitats. Thus preventing new invasion should be the first priority for land owners and respective government agencies. The integrated pest management (IPM) which combine several control methods (Paynter and Flanagan, 2004) should be taken into consideration for better result in managing Mimosa infestation.

Acknowledgement

The authors would like to thank Universiti Sains Malaysia for logistic and technical support.; Mr. Amir Shah Ruddin Md Shah and Mr. Zarul Hazrin Hashim for field assistance.

Literature cited

Anwar, A.I. and Sivapragasam, A. 1999. Impact and management of selected alien and invasive weeds and insect pests: a Malaysian perspective. Global Biodiversity Forum - South and Southeast Asia, Colombia, Sri Lanka. Benyasut, P. and Pitt, J.L. 1992. Preventing the introduction and spread of Mimosa pigra. In A guide to the management of Mimosa pigra, Harley, K.L.S. (ed.), CSIRO, Canberra, pp. 107-108. Braithwaite, R.W., Lonsdale, W.M., and Estbergs, J.A. 1989. Alien Vegetation and Native Biota in Tropical Australia - the Impact of Mimosa pigra. Biological Conservation. 48(3), 189-210. Chan, H.H., Yunos, K.M., and Ismail, A.R. 1981. Status of Mimosa pigra L. in Johore. Malaysian Plant Protection Society Newsletter. 5, 6. Forno, I.W., Miller, I.L., and Napompeth, B.T.S. 1989. Management of Mimosa pigra in South-East Asia and Australia. Malaysian Plant Protection Society, Genting Highlands, Pahang, Malaysia, pp. 40-54. Heard, T.A., Paynter, Q., Chan, R., and Mira, A. 2005. Malacorhinus irregularis for biological control of Mimosa pigra: host-specificity, life cycle and establishment in Australia. Biological Control. 32, 252-262. Lonsdale, W.M. 1992. The Biology of Mimosa pigra. In A guide to the management of Mimosa pigra. Harley, K.L.S. (ed.), CSIRO, Canberra, pp. 8-32. Lonsdale, W.M., Harley, K.L.S., and Miller, I.L. 1985. The biology of Mimosa pigra L. Asian Weed Science Society, Department of Agriculture, Bangkok, Thailand, pp. 484-490. Mansor, M. 1987. The spread of Mimosa pigra L. in Peninsular Malaysia. Weedwatcher, 2&3, 3. Marambe, B. 2001. Alien invasive plants threatening the agro-ecosystems of Sri Lanka., Secretariat of the Convention on Biological Diversity, Montreal, 1. Marambe, B., Bambaradeniya, C., Pushpa-Kumara, D. K., and Pallewata, N. 2001. Human dimensions of invasive alien species in Sri Lanka. In The Great Reshuffling - Human Dimensions of Invasive Alien Species, McNeeley, J.F. (ed.), IUCN, Gland, Switzerland and Cambridge, UK, pp. 135-142. Miller, I.L. and Pickering, S.E. 1983. Strategies for the control of Mimosa pigra in Australia. Robert, G.L. and. Habeck, D.H. (eds.), International Plant Protection Center, Corvallis, pp. 85-94. Mislamah, A.B., Norlia, R., and Hamzah, C. 1991. Mimosa pigra in Malaysia. Plant Quarantine Congress, Kuala Lumpur. Napompeth, B. 1983. Background, threat and distribution of Mimosa pigra L. in Thailand. Robert, G.L. and Habeck, D.H. (eds.), International Plant Protection Center, Chiang Mai, Thailand, pp. 15-26.

Proceedings of the 21st Asian Pacific Weed Science Society Conference (Editors: B. Marambe, U.R. Sangakkara, W.A.J.M. De Costa, and A.S.K. Abeysekara), 2-6 October 2007, Colombo, Sri Lanka. Othman, M.H. and Abu Hashim, A.K. 2003. Malaysia. p. 43-56. In Invasive Alien Species in South-Southeast Asia: National Reports and Directory of Resources. Pallewatta, N., Reaser, J.K. and Gutierrez, A.T. (eds.), Global Invasive Species Programme, Cape Town, South Africa. 111p. Paynter, Q. and Flanagan, G.J. 2004. Integrating herbicide and mechanical control treatments with fire and biological control to manage an invasive wetland shrub, Mimosa pigra. Journal of Applied Ecology. 41, 615-629. Robert, G.L. 1982. Economic returns to investment in control of Mimosa pigra. Robert, G.L. and. Habeck, D.H. (eds.), International Plant Protection Center, Corvallis, pp. 27-37. Samouth, C. 2004. Mimosa pigra infestation and the current threat to wetlands and flood plains in Cambodia. In Research and Management of Mimosa pigra, Julien, M. et al. (eds.), CSIRO Entomology, Canberra, pp. 29-32. Son, N.H., Lam, P.V., Cam, N.V., Thanh, D.V.T., Dung, N., Khanh, L.D., and Forno, I.W. 2004. Preliminary studies on control of Mimosa pigra in Vietnam. In Research and Management of Mimosa pigra, Julien, M. et al. (eds.), CSIRO Entomology, Canberra, pp. 110-116. Thamasara, S. 1982. Mimosa pigra management in irrigation systems in Thailand. Robert, G.L. and Habeck, D. H. (eds.), International Plant Protection Center, Corvallis, pp. 109-112. Triet, T., Kiet, L.C., Thi, N.T.L., and Dan, P.Q. 2004a The invasion of Mimosa pigra of wetlands of the Mekong Delta, Vietnam. In Research and Management of Mimosa pigra, Julien, M. et al. (eds.), CSIRO Entomology, Canberra, pp. 45-51. Triet, T., Man L. C., and Ngyuyen, P. N. 2004b. Impacts of Mimosa pigra on native plants and soil insect communities in Tram Chim National Park, Vietnam. In Research and Management of Mimosa pigra, Julien, M. et al. (eds.), CSIRO Entomology, Canberra, pp. 22-27. Winotai, A., Napompeth, B., and Charernsom, K. 1992. A brief review of problems and biological control of Mimosa pigra L. in Thailand. CSIRO Division of Entomology and Northern Territory Department of Primary Industry and Fisheries, Darwin, Australia.