to reprisals by villagers for damaging their crops. To mitigate the losses, the authorities have increased patrols, purchased additional speedboats for patrol, and created artificial highlands for shelter. Several corridors have been set up for the safe passage of animals across National Highway–37 which skirts around the southern boundary of the park. To prevent the spread of diseases and to maintain the genetic distinctness of the wild species, systematic steps such as immunization of livestock in surrounding villages and fencing of sensitive areas of the park, which are susceptible to encroachment by local cattle, are undertaken periodically. Water pollution due to run-off from pesticides from tea gardens, and run-off from a petroleum refinery at Numaligarh, pose a hazard to the ecology of the region. Invasive species such as Mimosa and wild rose have posed a threat to the native plants in the region. To control the growth and irradiation of invasive species, research on biological methods for controlling weeds, manual uprooting and weeding before seed settling are carried out at regular intervals. Grassland management techniques, such as controlled burning, are effected annually to avoid forest fires. Visitor activities Observing the wildlife, including birding, is the main visitor activity in and around the park. Guided tours by elephant or Jeep are available. Hiking is prohibited in the park to avoid potential human-animal conflicts. Observation towers are situated at Sohola, Mihimukh, Kathpara, Foliamari, and Harmoti for wildlife viewing. The Lower Himalayan peaks frame the park's landscape of trees and grass interspersed with numerous ponds. An interpretation centre is being set up at the Bagori range of Kaziranga, to help visitors learn more about the park. The park remains closed for visitors from 1 May to end-October due to monsoon rains. Four tourist lodges at Kohora and three tourist lodges outside the park are maintained by the Department of Environment and Forests, Government of Assam. Private resorts are available outside the park borders. Increase in tourist inflow has led to the economic empowerment of the people living at the fringes of the park, by means of tourism related activities, encouraging a recognition of the value of its protection. A survey of tourists notes that 80 percent found rhino sightings most enjoyable and that foreign tourists were more likely to support park protection and employment opportunities financially, while local tourists favored support for veterinary services. Recently set up Kaziranga National Orchid and Biodiversity Park