The complexities involved in conserving Scottish wildlife are highlighted in an RSPB report, noting that pine martens have been found to be a significant predator of capercaillie nests. Both species are protected, providing conservation agencies with a challenging conundrum to address. In 2012 the Scottish Government published a "Code of Practice on Non-Native Species" to help people understand their responsibilities and provide guidance as to which public body has responsibility for the various habitats involved. Various public sector organisations have an important role in the stewardship of the country's fauna. Scottish Natural Heritage is the statutory body responsible for natural heritage management in Scotland. One of its duties is to establish National Nature Reserves (NNR)s. Until 2004 there were 73, but a review carried out in that year resulted in a significant number of sites losing their NNR status, and by 2006 there were 55. there are 43. Forestry and Land Scotland serves as the forestry department of the Scottish Government and is one of the country's largest landowners. The Joint Nature Conservation Committee is the statutory adviser to Government on UK and international nature conservation. The country has two national parks. Cairngorms National Park includes the largest area of arctic mountain landscape in the UK. Sites designated as of importance to natural heritage take up 39% of the land area, two thirds of which are of Europe-wide importance. Loch Lomond and the Trossachs National Park includes Britain's largest body of fresh water, the mountains of Breadalbane and the sea lochs of Argyll. Charitable and voluntary organisations also have important roles to play. The National Trust for Scotland is the conservation charity that protects and promotes Scotland's natural and cultural heritage. With more than 270,000 members it is the largest conservation charity in Scotland. The Scottish Wildlife Trust is a leading voluntary conservation organisation, working to protect Scotland's natural environment. The Royal Zoological Society of Scotland is a learned society and registered charity that maintains Edinburgh Zoo and the Highland Wildlife Park (a safari park and zoo near Kingussie, which specialises in native fauna). The Society is also involved in various conservation programs around Scotland and the world. The Royal Society for the Protection of Birds promotes conservation of birds and other wildlife through the protection and re-creation of habitats. The John Muir Trust is a charity whose main role is as a guardian of wild land and wildlife, through the ownership of land and the promotion of education and conservation. The trust owns and manages estates in locations including Knoydart and Assynt, and on the isle of Skye.