How strong is the effect of invasive ecosystem engineers on the distribution patterns of local species, the local and regional biodiversity and ecosystem functions?

We will search a number of online databases to gather empirical evidence from the literature on the impacts of invasive ecosystem engineers on: (1) species richness and other univariate and multivariate measures of biodiversity; (2) productivity and abundance of algae, and animals; and (3) biogeochemical cycling and other flows of energy and materials, including trophic interactions. Data from relevant studies will be extracted and used in a random effects meta-analysis in order to estimate the average effect size of invasive ecosystem engineers on each response of interest.Ecosystem engineers (also termed habitat modifiers or bioconstructors) are defined as organisms that affect other biota via alterations to the abiotic environment [1,2] either directly with their bodies (e.g., add structure) or their activities (e.g., dig a hole) or indirectly through their biotic interactions (e.g., eat the canopy and let more light in the forest). Such species create, destroy, or otherwise modify habitats, and thereby affect resources or stressors (e.g., living space, sediment load, light availability and temperature) that have an impact on other organisms. Invasive species have the potential to play a dominant role as ecosystem engineers and can have ecosystem-level impacts by modifying their receptive environment, thus inhibiting or facilitating other species, either invasive or indigenous [3].Jones et al (1994) identified two types of ecosystem engineers (that are not mutually exclusive, i.e., a species can be both types) based on the way they alter the ecosystem:Autogenic engineers modify the environment with their own bodies which act as part of the engineered habitat and this engineering is dynamic (when engineers grow they can modify the environment in different ways). For example, as mussels grow, their shells increase the available habitat for other organisms (e.g., by providing settlement space and/or ameliorating environmental stress).Allogenic engineers are species