Detecting population trends of Gibson's and Antipodean wandering albatrosses
|Title||Detecting population trends of Gibson's and Antipodean wandering albatrosses|
|Publication Type||Journal Article|
|Year of Publication||2005|
|Authors||Elliott, G, Walker, K|
|Type of Article||paper|
|Keywords||Diomedea sp., mark-recapture, Population counts, simulation model|
Counts, mark-recapture estimates of abundance, and simulations were used to assess the population trends of Antipodean wandering albatross (Diomedea antipodensis) and Gibson's wandering albatross (D. gibsoni). Estimates of population size based on mark-recapture analysis had much greater power to detect trends than did annual counts of nests. In fact, nest counts were so variable that significant trends would only be detected when populations had already changed by more than 25%. Population simulation models were constructed using survival and productivity data from the two species, and recruitment data from closely related species. The simulation models were sensitive to variation in recruitment data and suggested that the recruitment of Gibson's wandering albatrosses is significantly lower than that of Antipodean wandering albatrosses. The sensitivity of the models to variation in the surrogate data compromises the usefulness of such models as predictive tools. After large, probably fisheries-induced declines during the 1970s and 1980s, Antipodean wandering albatross populations are now increasing at about 3.1% per annum, while Gibson's wandering albatross populations are static.