Complex sentence: In one field survey, three areas with high encounter rates in early 2008 were resurveyed in late 2008 and 2009, but no individuals were encountered, thought to be due to both high hunting pressures, and gold mine development.
Split into simpler sentences: In one field survey, three areas with high encounter rates in early 2008 were resurveyed in late 2008 and 2009, but no individuals were encountered. This change was thought to be due to both high hunting pressures and gold mine development.