lands have been developed for agricultural uses and human occupation, natural habitat has for the most part become limited to areas considered unsuitable for human use, such as slopes or rocky areas. This pattern of development limits the ability of animals, especially large ones, to migrate from place to place. Large carnivores are particularly affected by habitat fragmentation. These mammals, such as brown bears and wolves, require large areas of land with relatively intact habitat to survive as individuals. Much larger areas are required to maintain a sustainable population. They may also serve as keystone species, regulating the populations of the species they prey on. Thus, their conservation has direct implications for a wide range of species, and is difficult to accomplish politically due to the large size of the areas they need. With increasing development, these species in particular are at risk, which could have effects that carry down throughout the ecosystem. Conservation actions The threats to the Holarctic realm are not going unrecognized. Many efforts are being made to mitigate these threats, with the hope of preserving the biodiversity of the region. International agreements to combat global warming may help to lessen the effects of climate change on this region. Efforts are also underway to fight habitat fragmentation, both on local and regional scales. The most comprehensive effort to combat global warming to date is the Kyoto Protocol. Developed countries who sign this protocol agree to cut their collective greenhouse gas emissions by five percent since 1990 by sometime between 2008 and 2012. The vast majority of these nations are found within the Holarctic. Each country is given a target for emission levels, and they may trade emissions credits in a market-based system that includes developing countries as well. Once this period is ended, a new agreement will be written to further mitigate the effects of climate change. The process of drafting a new agreement has already begun. In late 2007, an international meeting in Bali was held to begin planning for the successor to the Kyoto Protocol. This agreement will aim to build on the successes and failures of Kyoto to produce a more effective method of cutting greenhouse gas emissions (UNFCCC). If these efforts are successful, the biodiversity of the Holarctic and the rest of the world will see fewer effects of climate change. Fighting habitat fragmentation is a major challenge in conserving the wide-ranging species