Peckarsky (1979) presents in situ studies of the movements of benthic stream invertebrates into and out of experimental cages. The conclusions drawn from these studies fall into two categories: species or species aggregates were characterized as having density-dependent or density-independent movements; and equilibrium benthic densities in cages were calculated and compared to natural densities...

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"New Zealand's immigration intake is small by the standards of the main immigrant receiving nations and many of her immigrants are subsequently lost through the process of re-emigration. Nevertheless, changes in New Zealand immigration policy over the last 10 years have been profound. This article is the first of a two-part history of these changes."

Few studies have addressed the effects of food availability as a proximate factor affecting local adult survival in long-lived organisms and their consequences at local population dynamics. We used capture-recapture analysis of resightings of 10 birth cohorts of ringed Audouin's gulls, Larus audouinii, to estimate adult survival and dispersal (both emigration and immigration). For the first tim...

1. Local extinctions in habitat patches and asymmetric dispersal between patches are key processes structuring animal populations in heterogeneous environments. Effective landscape conservation requires an understanding of how habitat loss and fragmentation influence demographic processes within populations and movement between populations. 2. We used patch occupancy surveys and molecular data ...

Demographic links among fragmented populations are commonly studied as source-sink dynamics, whereby source populations exhibit net recruitment and net emigration, while sinks suffer net mortality but enjoy net immigration. It is commonly assumed that large, persistent aggregations of individuals must be sources, but this ignores the possibility that they are sinks instead, buoyed demographical...

We offer an empirical, econometric analysis of the impact of migration on the EU 27's NUTS-2 regions in the period 2000-2007. While our results indicate that migration had no statistical impact on regional unemployment in the EU it had a significant impact on both per-capita GDP and productivity. The coefficients suggest that a 1 percent increase in immigration to immigration regions increased ...

Dispersal is a biological process performed in three stages: emigration, transfer and immigration. Intra-specific variation on dispersal behavior, such as sex-bias, is very common in nature, particularly in birds and mammals. However, dispersal is difficult to measure in the field and many hypotheses concerning the causes of sex-biased dispersal remain without empirical confirmation. An importa...

Italian Migration Italy is a country with a long history of emigration and a very short experience of immigration. The paper first surveys the Italian emigration pattern describing the characteristics of the Italian emigrants (age, sex, skill level), their area of origins and the directions of their movement. The determinants of the migration choice are then analyzed as well as the policies aff...

Biogeography-based optimization (BBO) is a new evolutionary algorithm that is inspired by biogeography. Previous work has shown that BBO is a competitive optimization algorithm, and it demonstrates good performance on various benchmark functions and real-world optimization problems. Motivated by biogeography theory and previous results, three variations of BBO migration are introduced in this p...