Liu_et_al_2025_Understanding_biological_invasions_through_the_lens_of_niche

Authors and Affiliations

• Chunlong LiuThe Key Laboratory of Mariculture, Ministry of Education, College of Fisheries, Ocean University of China, Qingdao, PR ChinaShandong Key Laboratory of Green Mariculture and Smart Fisheries, Qingdao, PR ChinaCorresponding Author: liuchunlong@ouc.edu.cn

• Céline BellardUniversité Paris-Saclay, CNRS, AgroParisTech, Ecologie Systématique Évolution, France

• Jonathan M. JeschkeLeibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, GermanyInstitute of Biology, Freie Universität Berlin, Berlin, Germany

Introduction to Biological Invasions

Biological invasions present significant ecological and economic challenges globally, often leading to loss of biodiversity, alteration of habitats, and shifts in ecosystem services. Understanding the stages of biological invasions is critical for developing effective conservation strategies and management practices.

Concept of Environmental Niche

The environmental niche is crucial for comprehending biological invasions as it integrates various factors affecting invasion success across all stages of the invasion process, which include:

• Transport: The movement of organisms from their native habitats to new environments.

• Introduction: The initial release and establishment of a species in a new habitat.

• Establishment: The ability of a species to survive and reproduce in a new environment.

• Spread: The expansion of a species within its new habitat.Current frameworks often focus narrowly on specific invasion stages; therefore, a more holistic approach is necessary to encompass the complexity of these processes.

The Framework Proposed

The proposed framework integrates the environmental niche with invasion processes at both the species and population levels. This integration helps elucidate interspecific (between species) and intraspecific (within a species) variations in invasion success and the impacts of non-native species on native ecosystems. Moreover, it highlights knowledge gaps and the flexibility needed to incorporate various factors influencing species success during invasions.

Key Components of the Environmental Niche

The environmental niche comprises the following essential components:

• Niche Breadth: This refers to the range of environmental conditions that can sustain a species population. A wide niche breadth can indicate resilience to environmental changes.

• Niche Matching: This assesses the suitability of conditions in recipient regions compared to those in occupied regions. Effective niche matching increases chances for establishment and spread.

• Distance to Niche Center: This is the discrepancy between current environmental conditions in the new area and those that are optimal for the species. Species facing long distances may struggle to thrive.

• Distance to Niche Margin: Refers to the extent of deviation from the limits of conditions required for positive growth. Species operating near their niche margin may be more vulnerable to invasive pressures.

Current Understanding of Invasion Success

Success in biological invasions varies among species and can be attributed to several characteristics such as:

• Genetic Diversity: High genetic variability can enhance adaptability to new environments.

• Survival Rates: Species with higher survival rates during transport and introduction tend to establish more successfully.

• Population Growth: Rapid population growth aids in quicker establishment and spread.

• Range Sizes: Larger native ranges may reflect a species' ecological prowess and resilience.The environmental niche framework reconciles ecological and evolutionary factors, providing a deeper understanding of potential invasion outcomes.

Literature Review of Existing Studies

The increasing availability of data on environmental factors and species distributions is critical in enhancing our understanding of ecological niches and how they relate to invasion success. Numerous studies quantitatively evaluate niche attributes, linking them to invasion success while focusing on broad ecological interpretations.

Niche Attributes in Relation to Invasion

• Transport and Introduction: Propagule pressure, defined as the size and frequency of species introductions, plays a significant role in determining invasion success. Species that are more accessible or preferred by humans typically exhibit higher rates of introducibility.

• Establishment: The ability to establish depends on the matching of environmental conditions in the new habitat to those found in the species' native range. Generalists, which possess broader niches, typically demonstrate higher rates of establishment success compared to specialists that have narrower niches.

• Spread: The capacity for spread hinges on a species' dispersal abilities and environmental tolerances. Generalist species tend to expand into varied introduced ranges more readily, which contributes to their success.

• Invasion Impacts: The impacts of invasions can be evaluated using the equation:I = R * A * Ewhere R represents the geographic range size, A indicates population abundance, and E refers to the per capita effect of the species. Generalist species often have larger impacts due to their higher abundance and adaptability.

Conclusions and Future Directions

A unified framework facilitates broader predictions regarding invasions for improved conservation management. Incorporating additional factors related to species characteristics and ecosystem invasibility significantly enriches our understanding. Future studies should leverage big data analytics and refine models for predicting invasions to enhance accuracy and efficacy.

Outstanding Questions

1. Are broader niches more likely to lead to successful invasions and result in significant ecological impacts?

2. How do the environments of populations correlate with their niche center's success?

3. What other factors could enhance the explanatory power of the environmental niche framework in the context of biological invasions?