Isotopic Tracking of Migrant Wildlife

摘要: KEITH A. HOBSONIntroductionAnimal movement, including dispersal and migration, is a phenomenon that captures the imagination of scientist layperson alike. In Northern Hemisphere, we are perhaps most familiar with annual movements birds much research has been devoted to understanding proximate ultimate mechanisms trigger these impressive patterns in nature (Ber-thold et al. 2003). However, tracking animal movements, those insects, fi sh, mammals, also an endeavor important both theoretical conservation disciplines. Unfortunately, have severely restricted our ability follow vagile organisms using conventional techniques rely on extrinsic markers. addition, many interest simply too small hold satellite or radio transmitters for direct monitoring (re-viewed by Hobson All studies initial capture ul-timate recapture individual typically subject sampling bias, especially species widespread distributions, so-called “nee-dle haystack” problem. contrast, methods intrinsic markers dependent only “recovery” sites. (2005a) referred this advantage as “every recapture”. The measurement naturally occurring stable isotopes tissues represents one means assaying animals order infer information their origins. Few areas involving application isotope ecological seen such explo-sive growth eld tracking, consequence funda-mental limitations (Hobson 2005b).Rubenstein & (2004) provided review relative advantages vs. track movements. Intrinsic biogeochemical include trace elements (Szep 2003) well each disadvantages. As elements, use based fact concentrations refl ect foodwebs spatial patterns, gradients, changes exist nature. Thus making iso-topic measurements knowing how isotopic pat-terns change spatially, it often possible By combining knowledge behavior