Understanding spatial and temporal dynamics of bird populations with a hierarchy of ecological approaches

The dynamics of bird populations are often governed by a range of ecological processes at different spatial and temporal scales. The quantity and quality of information available from ecological surveys also depend on the scale. Thus, for a thorough understanding of the dynamics of bird populations and their effective conservation, it is necessary to establish a set of approaches suited to ecological processes at hierarchical spatial and temporal scales. This paper focuses on three ecological approaches based on behavioural ecology, landscape ecology, and macroecology, and shows how these approaches can be used effectively to understand the dynamics of bird populations in a complementary manner. Behavioural ecology is helpful in understanding processes that produce patterns in spatial and temporal population dynamics at a local scale, by revealing decision-making in individual birds. This approach also makes it possible to develop behaviour-based models to predict spatial distribution and population dynamics under novel conditions. Landscape ecology focuses on the effect of landscape structures on biodiversity dynamics at the landscape level. At a larger spatial scale (macro-scale), climate, topography, and human activities are known to influence greatly population dynamics and spatial distribution of birds, but information available at this scale is usually limited because of the difficulty in conducting intensive field surveys. Macroecological approaches thus aim to understand such relationships by first quantifying spatial and temporal dynamics of bird populations and then generalizing the revealed dynamics based on species ecological traits. This review also discusses the advantages and disadvantages of the three approaches and suggests future tasks for promoting the understanding of the dynamics of bird populations at hierarchical spatial and temporal scales.