New article: Testing for environmental induced changes in ecology

In order to test hypotheses about changes in the environment induced by man, including climatic change, ecologists are sampling portions of the environment repeatedly across time.

This new paper co-authored by Miquel de Cáceres paper describes a method for testing a space–time interaction in repeated ecological survey data, when there is no replication at the level of individual sampling units (sites). This methodological development is important for the analysis of long-term monitoring data, including systems under anthropogenic influence. In these systems, an interaction may indicate that the spatial structure of community composition has changed in the course of time or that the temporal evolution is not the same at all sites.

This paper describes ANOVA models corresponding to the steps leading to a solution to the problem, which is based on the representation of space and time by principal coordinates of neighbor matrices (PCNM eigenfunctions) in the ANOVA. The paper presents two applications to real ecological data.

Legendre, P., De Càceres, M. & Borcard, D. 2010. Community surveys through space and time: testing the space–time interaction in the absence of replication. Ecology, 91:262–272.