Measuring dispersal as distance-dependent recruitment rates: testing the performance of DDRR on simulated data

Arie J. Noordwijk (1)

1 NIOO-KNAW - Netherlands Institute of Ecology

Dispersal is an important process in ecology, but its measurement is difficult. In particular, natal dispersal--the net movement between site of birth and site of first reproduction--is important, since it determines population structure. Using simulated data, I study the claim that measuring dispersal in terms of distance-dependent recruitment rates filters out many problems. Using several dispersal rules and several spatial distributions of breeding sites, it is shown that distance-dependent recruitment rate (DDRR) estimates are independent of the spatial distribution of breeding sites and are sensitive to differences in dispersal rules. These simulations were carried out with sample sizes of 200 individuals, which is a number exceeded in many studies. Variation in clumping of breeding sites (colony sizes) also has little effect on the resulting DDRR estimates. The effects of individuals entering and leaving the study area was simulated by assuming that only half the area was observed. Comparing the "observed" movements with the total distribution of distances dispersed shows that the shape of the DDRR is not affected, although the absolute values are, of course, lower. Thus, DDRR estimates will allow us to start studying dispersal behavior independent of the peculiarities of the study area and independent of the distribution of observer effort.

Mots clés: Methods; Spatial ecology; Breeding; Population dynamics; Observer effects; Behavior; Movement analysis

Arie J. Noordwijk. Measuring dispersal as distance-dependent recruitment rates: testing the performance of DDRR on simulated data. Journal für Ornithologie = Journal of Ornithology, 2011, 152 (S1), pp.239-249. ⟨10.1007/s10336-010-0637-2⟩. ⟨hal-00664098⟩