Human Impacts

PAPER

Human Impact on Plant Resources

Evidences from Western Chitwan, Nepal Introduction Human activities are principal causes for change in natural resources. These activities include environmental consumption and introduction of plant species for different purposes. The rural people of Nepal highly depend on plant resources for medicine, timber, fuel-wood, food, fodder plants, buildings, animal-sheds, wild genetic resources for improving crop plants, etc. In Nepal, many scientists explored and documented information on plant resource uses from different parts of Nepal. Among the useful plants recorded, a renowned ethnobotanist, Dr. N. P. Manandhar reported that 800 species were recorded as medicinal plants, 440 species as wild food plants, 100 species as fodder and animal bed, 71 species as fiber bearing plants, and 30 species as spices. This indicates that the people of Nepal exert pressure on plants of different ecosystems. To describe the impact of people on plant resources of forests and common lands of western Chitwan, Nepal, field observation and data gathered for “the reciprocal relationship study between population and environment conducted in 1996, 2000 and 2006” were used. Impact of conversion of land The forest and common lands are the habitats for growing indigenous plants. These lands are converted for the purpose of constructing huts, or buildings of clubs/ gymnasium/ temples. In some areas, common or forest 24

lands are converted to agricultural fields, agricultural lands to fallow or abandoned or protected areas in western Chitwan. This type of human activity replaces natural ecosystems temporarily or permanently and changes flora of the area. For instances, Oxalis corniculata, Rungia parviflora, Desmodium triflorum of the common lands of Ghailaghari of Jagatpur area were replaced by Urtica dioica, Clerodendrum viscosum, and Pogostemon benghalensis when the land was protected by Park and People Program in collaboration with local people of the area. Impact of agriculture In rural areas, farmers live in a house with a courtyard, kitchen garden and khetland or bariland. They also keep some animals, especially buffalo, cattle, goats and sheep. To keep animals and store other farm products (straw) and fuelwood, each farmer has a Dhansar. They also have planted Bakaino for fodder and fuelwood or Euphorbia roylena as hedge plants. Some farmers use local plants, for example, Justicia adhatoda as green manure and Artemisia dubia as insect repellent. Agricultural entomologists are now searching alternative way to replace or find out the integrated pest management. They are conducting experiments to screen effectiveness of plants for controlling insect pests of different crops. If the tested botanicals are used on commercial scale, the change on vegetation may be marked due to mass exploitation of the plants for their products.

Impact of grazing or fodder collection Domestic animals either graze in the natural or man-made environments or stall-feed. Due to daily use of the track by the animals and even by humans, one can see the trampling effect on the ground flora. Animals are also selective in grazing and graze on plants, which are palatable. The unpalatable plants are left in the ground, as a result the habitat is covered by weedy species like Lantana camara, Eupatorium odoratum, Clerodendrum viscosum, Parthenium hysterophorus, Ageratum houstonianum especially on the grounds of the roadsides, canalways and other common lands. Impact of tourism industry In Chitwan, Wildlife tourism is very famous and uses the riverine forest and the grassland habitats to see one-horned rhinoceros, peacock, deer, hogs, fowls, etc. in the Chitwan National Park and villages/ parts of western Chitwan. As a result of tourists flow in Chitwan, many hotels and lodges were made using local plant materials including plant canes, poles, posts, beams and plant fibers. In the lodge or hotel environment, also a lot of alien ornamental plants were introduced for beautification. Some plants, for example Justicia gendarusa- a common species with strong propagating potential, are becoming problem even in the jungle of National Park. Besides, this industry also consumes a lot of fuelwood for warming rooms, NTTR December 17 - 30, 2007

PAPER boiling water, and for camp firing. Impact of social and religious activities Religious people, especially women, need lot of flowers to worship the god and goddess. They pick up flowers from different places. The environment of the temples may have many ornamental plants such as Poinsettia pulcherrima, Nyctanthes arbortris, Hibiscus rosa-sinensis, Catharanthus roseus, Thevetia peruviana, and Cynodon dactylon. Impact of conservation education and research To protect biodiversity and ecosystems, many organizations and individuals are conducting research and training events on conservation of habitats and species. As a result of such activities, people became aware about nature conservation and started to participate in the protection of nature, culture, indigenous knowledge and biodiversity. Park and People program, for example, protected a forested area mobilizing local people of the area. As a result of protection, tall forest shrubs replaced the herbaceous ground vegetation of a place and herbs and rhinos started to come from the jungle and live there. The impact of research activities may be cited giving the example of Ecological Services Center or Rampur Campus. In Rampur Campus, researchers are introducing germplasms of citrus collected from different parts of Nepal in the research farm. This also brought changes in the weed vegetation of the citrus plantation area. Impact of resource utilization People of western Chitwan utilize plant resources of forests as well as common lands for many purposes, including timber, food, medicine, fodder, fuelwood, and many others. Overexploitation of the plant resource causes the resource depletion, biodiversity loss, environmental degradation, etc. Due to overexploitation, some of the species, for example Rauwolfia serpentina, Asparagus racemosus, Helicteres isora already became rare or NTTR December 17 - 30, 2007

endangered in the forests of western Chitwan. Impact of alien plants In western Chitwan, many alien plants are introduced in forest and common lands. Many alien species, for example Ageratum houstonianum, is naturalized not only in agricultural fields but also in natural forests, community forests, and common lands. Such species are responsible for replacing useful species, especially fodders grasses. Other common invasive alien species such as Lantana camara, and Eupatorium odoratum are abundantly found on the roadsides, playing grounds and paths that are the habitats for invasive species. In addition, residents of western Chitwan also cultivate many alien species for beautification. The widely cultivated ornamental species include: Tabermontana coronariea, Hibiscus rosa-sinensis, Polyalthia longifolia and pendula, Roses, Poinsettia pulcherrima, Tagetus spp., Gladiolus spp., etc. Impact of construction works In our study area, B. P. Memorial Cancer Hospital gives a picture of a change in the former Yagya Puri Horticulture Farm. Here, the land of orchards was converted to construct buildings and roads of the hospital. Further, the roads were black topped or graveled leaving no space for growing plants. Most of the areas were cleared for planting

ornamental plants such as Acalypha hispida, Dahlia, Bougainvillea, and other annuals and perennials for beautification of the area replacing indigenous plants. Conclusion Neighborhoods of western Chitwan use plants for many purposes. Because of utilization of the resources, many plants, which are useful, are getting under pressure. The human pressure on the species becomes higher when the species have multi-uses. The trees, which have timber as well as fodder and fuelwood value, receive higher pressure. Some plants with multiuses are Dalbergia sissoo, Shorea robusta, Terminalia alata, Phyllanthus emblica, Trewia nudiflora. Such multipurpose trees are illegally cut for timber or fuelwood or fodder. Acknowledgements This research was supported by a grant from the National Institute of Child Health and Human Development (Grant # Rol-HD 33551), USA. I extend my sincere thanks to Dr. William G. Axinn (Principal Investigator) and Dr. D. J. Ghimire for encouraging me to write papers. Dr. Dharma Raj Dangol Senior Research Associate in Institute for Social and Environmental Research, Fulbari, Chitwan, Nepal [email protected], [email protected] 25