From twigs to landscapes – methods for studying ecological effects of forest ungulates

In recent decades considerable attention has been focused on plant-ungulate interactions at various spatial and temporal scales. The cascading effects following ungulate actions are also attracting increasing interest. Our knowledge of the effects of ungulates on plants, communities, landscapes and ecosystems is, therefore, growing. At the same time, shifts in ungulate populations (increases and decreases) in various forested parts of the world together with mounting interest in biodiversity issues have heightened management concerns about plant-ungulate interactions. This paper reviews methodologies commonly applied to the study of ungulate-induced effects at various scales. Non-experimental comparisons have long been used, while simulation and exclosure methods were developed decades ago. However, these methods have been progressively refined, the objectives of studies based on them have broadened, and the results obtained have increasingly highlighted the interactive and dynamic nature of plant-ungulate interactions. Recent research has exploited various new techniques, such as remote sensing, to gather and process data over larger spatial scales, while others, such as GIS and powerful modelling and statistical methods are opening up new ways to analyse data and present information. The nature, design and use of the various commonly used methods, as well as their potentials and limitations, are discussed.