INTERACTIONS
Intricate but harmonious interactions between plants, animals and their environment exist in the complex and species-rich tropical forest ecosystem of Malaysia. In food chains and energy flows, for example, autotrophic or photosynthesizing plants are the primary producers, while animals and other heterotrophic or non-photosynthesizing plants are the consumers. Green plants possessing chlorophyll perform photosynthesis. During this process, inorganic carbon dioxide from the atmosphere and water absorbed by the roots are converted, with the help of sunlight, into organic compounds in the form of carbohydrates, proteins and vitamins. These photosynthetic products are then transferred to and stored in various plant tissues, such as roots, stems and branches, leaves, flowers, fruits and seeds. Through various means, animals and other heterotrophic organisms utilize photosynthetic products as food. When plants and animals die, organisms like bacteria and fungi begin to decompose the dead organic matter, returning its inorganic nutrients to the ecosystem.
Plant communities in the forest also provide homes for animals in which to breed and raise their offspring. In return, certain animals, including insects, birds, bats, squirrels, primates, civets, elephants and tapirs, act as pollinators of flowers or dispersers of fruits and seeds. For successful seed germination and seedling establishment of many plant species, the assistance of a fungus or bacteria is sometimes needed. To avoid being damaged by the animals, the plants protect themselves by developing hard tissue or by producing chemicals that are poisonous or unpalatable. In ant-plants, the harmonious interaction is mutually beneficial. Plants, such as Macaranga triloba, provide the ants with food and a place to live and breed, while the ants protect the plant from being attacked by herbivores. Ants that live in Myrmecodia tuberosa also collect and accumulate organic and inorganic debris which is tapped by the plants' roots.
Interactions between plants and the environment are seen in photosynthesis, respiration and evapotranspiration. Through these processes, plants and forests play important roles in maintaining the environmental quality and the ecological balance of their surrounding areas. Particularly important is the function of forests and other vegetation types in the hydrological and nutrient cycles and in maintaining heat balance and regulating the oxygen and carbon dioxide content of the atmosphere. The presence of dense vegetation in water catchment areas also helps in reducing soil erosion and siltation of rivers and streams, thereby ensuring a supply of clean water. In cities and other urban areas, plants are grown in gardens, along roadsides, and in parks and other open spaces to mitigate and alleviate the impact of air, heat, noise and water pollution, as well as to create a more pleasant living environment.
