Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

CABI Book Chapter

Invasion biology: hypotheses and evidence.

Book cover for Invasion biology: hypotheses and evidence.


This book, containing 18 chapters, combines the hierarchy-of-hypotheses (HoH) approach with hypothesis networks for invasion biology. This book aims to further develop the HoH approach by inviting critical comments (Part I), apply it to 12 major invasion hypotheses (Part II) and explore how it can be expanded to a hierarchically structured hypothesis network (Chapter 7 and Part III). It is importa...

Chapter 10 (Page no: 79)

Invasional meltdown hypothesis.

Positive interactions among species can be central for community structure and ecosystem functioning. Given the current scenario of species invasions worldwide, the question arises how non-native species will interact in the new environment. Such reasoning has led to the invasional meltdown hypothesis (IM) which states that non-native species facilitate one another's invasion, increasing their likelihood of survival, ecological impact and possibly the magnitude of their impact. However, given the importance of antagonistic interactions in natural communities, it is not yet known to what extent these facilitative effects of non-native species occur. We used the hierarchy-of-hypotheses (HoH) approach to differentiate key aspects of IM and link empirical studies to specific sub-hypotheses of the overall hypothesis. Evidence related to IM was gathered by assessing citations of Simberloff and Von Holle (1999) who first defined it. Our HoH was categorized by the type of interaction among non-native species (e.g. facilitation, mutualism and multi-species interactions), ecological level of evidence and the outcome of the interaction for each non-native species (i.e. response variable measured in the study). We additionally looked for taxonomic and geographic variability. On the basis of the 208 relevant studies we found, the broad hypothesis and the majority of sub-hypotheses indicate that positive interactions among non-natives are happening more frequently than negative ones. Thus, IM is broadly supported by currently available studies. Evidence against IM relates to sub-hypotheses involving reciprocal interactions (e.g. competition between non-native species). We suggest that future research focuses on controlled experimental setups aiming at elucidating the community- or ecosystem-level effects of non-native species interactions, especially for reciprocal interactions.

Other chapters from this book

Chapter: 1 (Page no: 3) Invasion biology: searching for predictions and prevention, and avoiding lost causes. Author(s): Cassey, P., García-Díaz, P., Lockwood, J. L., Blackburn, T. M.
Chapter: 2 (Page no: 14) The hierarchy-of-hypotheses approach. Author(s): Heger, T., Jeschke, J. M.
Chapter: 3 (Page no: 19) Hierarchy of hypotheses or hierarchy of predictions? Clarifying key concepts in ecological research. Author(s): Farji-Brener, A. G., Amador-Vargas, S.
Chapter: 4 (Page no: 23) Mapping theoretical and evidential landscapes in ecological science: Levins' virtue trade-off and the hierarchy-of-hypotheses approach. Author(s): Griesemer, J.
Chapter: 5 (Page no: 30) A hierarchy of hypotheses or a network of models. Author(s): Scheiner, S. M., Fox, G. A.
Chapter: 6 (Page no: 38) The hierarchy-of-hypotheses approach updated - a toolbox for structuring and analysing theory, research and evidence. Author(s): Heger, T., Jeschke, J. M.
Chapter: 7 (Page no: 49) A network of invasion hypotheses. Author(s): Enders, M., Jeschke, J. M.
Chapter: 8 (Page no: 60) Biotic resistance and island susceptibility hypotheses. Author(s): Jeschke, J. M., Debille, S., Lortie, C. J.
Chapter: 9 (Page no: 71) Disturbance hypothesis. Author(s): Nordheimer, R., Jeschke, J. M.
Chapter: 11 (Page no: 92) Enemy release hypothesis. Author(s): Heger, T., Jeschke, J. M.
Chapter: 12 (Page no: 103) Evolution of increased competitive ability and shifting defence hypotheses. Author(s): Müller, C.
Chapter: 13 (Page no: 124) Tens rule. Author(s): Jeschke, J. M., Pyšek, P.
Chapter: 14 (Page no: 133) Phenotypic plasticity hypothesis. Author(s): Torchyk, O., Jeschke, J. M.
Chapter: 15 (Page no: 140) Darwin's naturalization and limiting similarity hypotheses. Author(s): Jeschke, J. M., Erhard, F.
Chapter: 16 (Page no: 147) Propagule pressure hypothesis. Author(s): Jeschke, J. M., Starzer, J.
Chapter: 17 (Page no: 157) Synthesis. Author(s): Jeschke, J. M., Heger, T.
Chapter: 18 (Page no: 167) Conclusions and outlook. Author(s): Heger, T., Jeschke, J. M.