Colonization in metapopulations: a review of theory and observations

Abstract

In metapopulation dynamics turnover of populations in isolated patches may be frequent. Regional survival of a species in such a system with frequent extinctions hinges on its colonization ability. Colonization is more than just dispersal; when a propagule reaches a new patch i t Faces higher extinction probabilities than does an established population. Extinction models as wrll as empirical data suggest that a large propagule with a potential for rapid increase in a varying environment, 01 with a low mortality rate in an environment perceived as constant, has a higher probability of successful colonization. Large variation in population size when it is still small increases the risk of failure. Factors introducing such variation are dcmographic stochasticity and environmental variation. It is hard to single out demographic traits that ensure good colonizing ability, since colonization can be achieved in many direrent ways, but generalists and species with selffertilization seem to be superior.

Metapopulation dynamics: brief history and conceptual domain

“…Hansson (1991) discusses the different categories of animal movement and relates them to the dispersal process. Ebenhard (1991) extends the original work of MacArthur & Wilson (1967) on the establishment of arriving individuals at a habitat patch, the colonization process.…”

Indirect measures of gene flow and migration: FST≠1/(4Nm+1)

“…Island biogeography theory predicts variance in migrant number for a variety of reasons (MacArthur & Wilson, 1967), as has often been observed in natural populations (Ebenhard, 1991). Furthermore, dispersal is often distance dependent, such that populations near many other populations receive a greater number of migrants, whereas more isolated populations receive fewer (Brown & Kodric-Brown, 1977).…”

Tackling degradation of a seminatural landscape: options and evaluations

“…Critical to this idea of a 'landscape' is the mutual support between aquatic and terrestrial elements. For example, amphibian metapopulations (Ebenhart, 1991) require several elements including: (a) clusters of 'suitable' ponds (in water quality, species composition, successional state); (b) a supportive terrestrial matrix around and between the ponds, affording foraging and hibernation resources, and (c) a high matrix permeability allowing interpond dispersal both annually and for (re)colonization. Degradation of a pond landscape can thus be recognized by (a) lowered pond densities towards or below a critical level, (b) deleterious changes to the matrix which remove support functions and (c) impedance of dispersal routes.…”