Quantifying loss and degradation of former American marten habitat due to the impacts of forestry operations and associated road networks in northern Idaho, USA [Chapter 12]

The global human population has more than tripled in the past century, reaching seven billion in 2012. The total footprint of humanity on the biosphere has more than doubled since the mid-twentieth century (Vitousek et al. 1997). Every year globally more than 14 million hectares of natural forest are converted to other land uses (FAO 2011), and many other ecosystems, such as temperate grasslands, are mere remnants of their original area. More than 30% of Earth’s annual primary productivity is utilized directly by humans (Vitousek et al. 1986) and between one-third and one-half of Earth’s land surface has been transformed by human action. As a result, many scientists estimate that between 33% and 50% of all species of mammal may become extinct by the end of the twenty-first century (Leakey and Lewin 1996; Wilson 2002).