▁Trans formation : ▁Political ▁Cont ing ency , ▁Historical ▁E col ogy , ▁and ▁the ▁Ren eg ot iation ▁of ▁Nature ▁in ▁Central ▁Ser am ” ( 2 0 0 8 ) ▁is ▁one ▁of ▁Ellen ' s ▁most ▁influ ential ▁works . ▁He ▁applied ▁a ▁historical ▁perspective ▁to ▁understand ▁the ▁N ua ulu ' s ▁current ▁relationship ▁with ▁nature . ▁He ▁offered ▁that ▁nature ▁co - e vol ves ▁with ▁humans . ▁Ch anges ▁that ▁have ▁acceler ated ▁in ▁the ▁last ▁ 2 0 ▁years ▁such ▁as ▁c ash ▁cro pping ▁and ▁forest ▁extra ction ▁have ▁ren eg oti ated ▁the ▁N ua ulu ' s ▁relationship ▁with ▁nature . ▁ ▁“ How ▁people ▁concept ual ize ▁nature ▁depends ▁on ▁how ▁they ▁use ▁it , ▁how ▁they ▁transform ▁it , ▁and ▁how ▁in ▁doing ▁so ▁they ▁invest ▁knowledge ▁in ▁a ▁different ▁part ▁of ▁it ” ▁( 2 0 0 8 : ▁ 3 2 6 ). ▁He ▁is ▁influenced ▁by ▁Les lie ▁White ' s ▁energy ▁capture ▁theory . ▁ ▁The ▁technology ▁available ▁has ▁a ▁great ▁impact ▁and ▁changes ▁people ' s ▁per ception ▁of ▁nature , ▁as ▁it ▁is ▁instrument al ▁in ▁the ▁evolution ▁and ▁adv ancement ▁of ▁our ▁species . ▁ ▁The ▁work ▁of ▁Roy ▁Ellen ▁contributed ▁to ▁anth rop ologist ' s ▁understanding ▁of ▁the ▁inter rel ations hip ▁between ▁nature ▁and ▁culture ▁and ▁helped ▁anth rop ology ▁contribute ▁to ▁practical ▁deb ates ▁that ▁depend ▁on ▁definitions ▁of ▁nature ▁such ▁as ▁sust ain able ▁development . ▁ ▁He ▁focused