Paleoecology (also spelt palaeoecology) uses data from fossils and subfossils to reconstruct the ecosystems of the past. It involves the study of fossil organisms and their associated remains (such as shells, teeth, pollen, and seeds), which can help in the interpretation of their life cycle, living interactions, natural environment, communities, and manner of death and burial. Such interpretations aid the reconstruction of past environments (paleoenvironments).
Paleoecologists have studied the fossil record to try to clarify the relationship animals have to their environment, in part to help understand the current state of biodiversity. They have identified close links between vertebrate taxonomic and ecological diversity, that is, between the diversity of animals and the niches they occupy.
The aim of paleoecology is therefore to build the most detailed model possible of the life environment of previously living organisms found today as fossils. Such reconstruction takes into consideration complex interactions among environmental factors such as temperatures, food supplies, and degree of solar illumination. Often much of this information is lost or distorted by the fossilization process or diagenesis of the enclosing sediments, making interpretation difficult.
The environmental complexity factor is normally tackled through statistical analysis of the available numerical data (quantitative paleontology or paleostatistics), while the study of post-mortem processes is known as the field of taphonomy.
Much of the original paleoecological research has focused on the last two million years (the Quaternary period), because older environments are less well represented in the fossil timeline of evolution. Indeed, many studies concentrate on the Holocene epoch (the last 11,500 years), or the last glacial stage of the epoch (the Wisconsin/Weichsel/Devensian/Würm glaciation of the ice age, from 50,000 to 11,500 years ago). Such studies are useful for understanding the dynamics of ecosystem change and for reconstructing pre-industrialization ecosystems. Many public policy decision-makers have pointed to the importance of using palaeoecological studies as a basis for choices made in conservation ecology.