If the deterministic threats of fragmentation can be stopped or reversed, species may find opportunities to disperse between patches and reduce the risk of extinction. In order to realize these opportunities and apply them to conservation programs it is necessary to understand dynamics and to estimate capacity of sustainability of species at the landscape level. A regional population consisting of several sub-populations, the Incidence function model (IFM) is stochastic, spatially realistic patch occupancy model which can be applied using few parameters. With this model one can simulate and manipulate a patch network for a species. In IFM, the extinction probability is assumed to be proportional to local population size which in turn is assumed to be proportional to the local patch area. Although, the basic area of patches is of importance, influence from the geometric shape of patches may be equally or more important to determine potential incidence of a species in a particular patch. Basic area measurements might overestimate the probability of occupancy and/or capacity of a certain patch network to sustain a metapopulation. To deal with regional dynamics in fragmented landscapes one applicable method is metapopulation capacity. Metapopulation capacity is derived from metapopulation theory and can be used to rank different patch networks. In this study we examine if there is any difference of occupancy level and capacity between four different area scenarios. This is done in order to determine if basic area measurement of patches can result in a biased estimation of population viability in a specific landscape. It is concluded that perimeter-area related measures of patch size combined with capacity could be a more important measure for estimation of population dynamics and impact of landscape changes compared to basic area measurement and occupancy levels.
Keywords: Ecological niche factor analysis, Fragmentation, Incidence function model, Landscape, patch occupancy model, perimeter-area ratio.