Ecology Letters (2011) 14: 615–624 Abstract Biological invasions are a global and
increasing threat to the function and diversity of ecosystems. Allee effects (positive density …

Understanding the dynamics of small populations is obviously important for declining or rare
species but is also particularly important for invading species. The Allee effect, where fitness …

Allee effects are (broadly) defined as a decline in individual fitness at low population size or
density. They can result in critical population thresholds below which populations crash to …

Allee effects are a density-dependent phenomenon in which population growth or individual
components of fitness increase as population density increases. They are named after North …

Allee effects, strongly related to the extinction vulnerability of populations and gradually
becoming acknowledged by both theoretically oriented and applied ecologists, have already …

Summary 1 In a population with Allee effects a positive relationship exists between fitness
and population size or density. Allee effects may result in extinction thresholds and are …

We aim to develop a simple model to explore how disturbance and propagule pressure
determine conditions for successful invasion in systems where recruitment occurs only in …

Many factors, both biotic and abiotic, impede the success of reintroductions. Among these is
the difficulty that small populations have in surviving and thriving. For many species of …

All species' ranges are the result of successful past invasions. Thus, models of species'
invasions and their failure can provide insight into the formation of a species' geographic …

Allee effect that refers to a positive relationship between individual fitness and population
density provides an important conceptual framework in conservation biology. While …