Bestandsstørrelse

Bestandsstørrelse is a term used in ecology and wildlife management referring to the number of individuals in a population of a given species, typically within a defined geographic area and time frame. The concept is closely related to population size, and is distinct from population density (the number of individuals per unit area) and from aspects like age structure or genetic diversity.

Estimating bestandsstørrelse involves a range of methods. Direct counts work for conspicuous or small areas, while transect and point-count surveys are used for mobile or cryptic species. Capture–mark–recapture, camera-trap monitoring, and acoustic surveys provide data for elusive populations, often with statistical models to correct for imperfect detection. Genetic methods can also help infer population size from samples. In forestry-related contexts, bestandsstørrelse may refer to stand-level attributes such as the number of trees or the total biomass per stand.

Population size is influenced by births, deaths, immigration, and emigration, as well as environmental variation and density-dependent factors. Growth can be described by simple models, such as exponential growth, N_t = N_0 e^{rt}, or logistic growth that incorporates carrying capacity. Real populations exhibit stochastic fluctuations due to random events and climate change, and size estimates carry uncertainty from sampling and detection biases.

Applications of bestandsstørrelse data include conservation status assessments, wildlife management and harvesting quotas, ecological research, and population viability analyses. Accurate estimates support informed decision-making and help monitor trends over time.