Methods for assessing the effects of environmental parameters on biological communities in long-term ecological studies - A literature review

• Published in: Ecological modelling 2019-12, Vol.414, p.108732, Article 108732
• Main Authors: Verniest, Fabien, Greulich, Sabine
• Format: Article
• Language: English
• Subjects: Data analysis; Environmental studies; Humanities and Social Sciences; LTER; Modelling; Multivariate data; Sampling; Statistics
• ISSN: 0304-3800; 1872-7026
• DOI: 10.1016/j.ecolmodel.2019.108732

•Most of the long-term ecological studies are conducted in aquatic habitats.•The reviewed studies considerably differ in their design but have analogous aims.•Univariate methods are more frequently used than multivariate techniques.•Univariate tools are mostly linear models and correlation tests.•Constrained and unconstrained ordination techniques are evenly employed. Many ecological processes that play important roles in ecosystems occur over long time periods and can therefore not always be properly studied with short-term studies. However, researchers have to face many challenges while setting up long-term ecological studies, including the choice of relevant data analysis methods and the design of the study (i.e. sampling frequency, number of sites, etc.). This literature review, based on 99 original studies, provides an overview of methodological choices used to analyse the effects of abiotic parameters on biological communities on a long-term scale. To this end, the main characteristics of study design were recorded (e.g. sampling frequency, duration, taxa, variables) and the different data analysis tools summarised and analysed. We found that long-term ecological studies focusing on the effects of environmental factors on biotic parameters mostly concerned aquatic habitats. Studies substantially varied in their design, although many of them had similar aims. Univariate methods, almost entirely performed by means of linear modelling and correlation tests, were used more often than multivariate methods. Finally, constrained and unconstrained ordination methods were used equally, and other data analysis tools were rare. Finally, we created a decision key to help researchers choose the appropriate analysis tools for their specific long-term study.