قارن الطرق

	نموذج الإسقاط المتكامل	تحليل جدوى التجمعات السكانية (Population Viability Analysis)
المجال	علم البيئة	علم البيئة
العائلة	Process / pipeline	Process / pipeline
سنة النشأة	2000	1981
صاحب الطريقة	Stephen Ellner and Mark Rees	Mark Shaffer
النوع	size-structured population projection	extinction risk assessment
المصدر التأسيسي	Easterling, M. R., Ellner, S. P., & Dixon, P. M. (2000). Size-specific sensitivity: applying a new structured population model. Ecology, 81(3), 694-708.	Shaffer, M. L. (1981). Minimum population sizes for species conservation. BioScience, 31(2), 131-134.
الأسماء البديلة	IPM, continuous size structure, kernel model, size-structured population	PVA, extinction risk, minimum viable population, MVP
ذات صلة	4	4
الملخص	Integral projection models (IPMs) are a class of structured population models that use continuous traits (size, age, height) to describe population dynamics. Introduced by Easterling and colleagues (2000) and developed extensively by Ellner, Rees, and collaborators, IPMs overcome limitations of age- or stage-structured models by treating individual traits as continuous. They use integration to project populations forward in time, making them particularly suitable for organisms with continuous size distributions or flexible developmental pathways. IPMs enable estimation of population growth rate (λ), sensitivity analysis, and projection under changing environmental conditions.	Population Viability Analysis (PVA), introduced by Shaffer (1981), estimates the probability that a population will persist over a given time period under specified conditions. PVA combines demographic models (Leslie matrices, IPMs) with stochastic simulation to project population trajectories, quantifying extinction risk. This allows conservation planners to assess whether a population will likely persist, evaluate management scenarios, and estimate the minimum viable population (MVP) size for long-term persistence. PVA is a decision-support tool, not a precise predictor.