Melbourne, Nov 25 : Changes in wildfire intensity and frequency driven by human activities are putting at risk more than 4,400 species across the globe, says a study. A large proportion of these species is critically endangered or vulnerable. "Those species include 19 per cent of birds, 16 per cent of mammals, 17 per cent of dragonflies and 19 per cent of legumes that are classified as critically endangered, endangered or vulnerable," said lead author, Luke Kelly, Senior Lecturer at University of Melbourne, Australia. "That's a massive number of plants and animals facing threats associated with fire." The paper, published in the journal Science, found that the species categorised as threatened by an increase in fire frequency or intensity, include the orangutan in Indonesia and mallee emu-wren in Australia. "Recent fires have burned ecosystems where wildfire has historically been rare or absent, from the tropical forests of Queensland, Southeast Asia and South America to the tundra of the Arctic Circle," Kelly said. "Very large and severe fires have also been observed in areas with a long history of recurrent fire, and this is consistent with observations of longer fire seasons and predictions of increased wildfire activity in the forests and shrub lands of Australia, southern Europe and the western United States." However, some species and ecosystems are threatened when fire doesn't occur. Frequent fires, for example, are an important part of African savanna ecosystems and less fire activity can lead to shrub encroachment, which can displace wild herbivores such as wildebeest that prefer open areas. "Understanding what's causing changes in different places helps us to find effective solutions that benefit people and nature," Kelly said. Researchers, including 27 authors from a combined 25 institutions around the world, identified three main groups of human drivers as transforming fire activity and its impacts of biodiversity: global climate change, land-use and biotic invasions. This means that people and governments around the world need to act and confront the diverse changes to the environment that are occurring. "It really is time for new, bolder conservation initiatives," Kelly said. "Emerging actions include large-scale habitat restoration, reintroductions of mammals that reduce fuels, creation of low-flammability green spaces and letting bushfires burn under the right conditions. The role of people is really important: Indigenous fire stewardship will enhance biodiversity and human well-being in many regions of the world." /IANS