Application of harmonic radar technology to monitor tree snail dispersal

摘要: Abstract. Planned conservation efforts for tree snails of the endangered genus Achatinella, endemic to island O'ahu, Hawai'i, will include translocations among remaining wild and captive-bred populations. In order establish optimal levels artificial migration neighboring groups within fragmented populations, determine natural dispersal rates through direct observation were initiated. Capture–mark–recapture (CMR) have proved inadequate obtaining requisite estimates, due low recapture probabilities. addition, snail beyond boundaries a finite CMR study site was indistinguishable from mortality. preliminary reported here, both probability detection problems past addressed by using harmonic radar tracking. This approach yielded rough estimates that unattainable alone providing 100% even normal survey area boundaries. Extensive movements clusters connected trees frequently observed after tracking merely few hours, although between unconnected rare recorded only monthly intervals. Just 11 out 40 tracked made between-tree (average distance 4.94±1.52 m) during entire 7-month study, provided data utilizable inferring gene flow in subpopulations. Meteorological loggers deployed when began look an association such movement weather fluctuations. The resultant indicate increases wind gusts humidity facilitate (R2=0.77, p-value <0.001), passive may be responsible many (R2=0.59, p-value=0.0014). Despite having coarse short-term corresponding influences, limitations method can substantial.