Related Experiment Video
Updated: May 6, 2026
09:19
Measuring the Structure, Composition, and Change of Underwater Environments with Large-area Imaging
Published on: April 18, 2025
1.6K
Differences in ecological structure, function, and native species abundance between native and invaded Hawaiian
Tara M Holitzki1, Richard A MacKenzie, Tracy N Wiegner
1Tropical Conservation Biology and Environmental Science, University of Hawai'i at Hilo, 200 West Kawili Street, Hilo, Hawaii 96720, USA. holitzki@hawaii.edu
Summary
Invasive poeciliids significantly alter tropical stream ecosystems, increasing nutrient yields and impacting native fish and macroinvertebrate communities. These findings highlight the urgent need for managing these invasive species in Hawaii and globally.
Area of Science:
- Tropical stream ecology
- Invasive species biology
- Ecosystem impact assessment
Background:
- Poeciliids are a globally invasive fish family, recognized as a significant concern in the US, Australia, and New Zealand.
- Their ecological impacts on tropical stream ecosystems, however, remain underquantified.
- Hawaiian streams provide a valuable model system for studying these impacts due to their unique biodiversity and susceptibility to invasion.
Purpose of the Study:
- To quantify the ecological differences between poeciliid-invaded and poeciliid-free tropical streams in Hawaii.
- To assess the effects of poeciliid invasion on stream ecosystem structure, function, and native biodiversity.
- To provide data supporting the need for invasive poeciliid management strategies.
Main Methods:
- Comparison of ecological parameters (nutrient yields, biofilm biomass, macroinvertebrate and fish densities, community structures) between invaded and uninvaded Hawaiian streams.
- Quantification of nutrient loads, including sum nitrate (sigmaNO3-), total nitrogen, and total organic carbon.
- Analysis of benthic biofilm biomass and community composition of algae, macroinvertebrates, and fish.
Main Results:
- Poeciliid-invaded streams exhibited significantly higher nutrient yields (8x nitrate, 6x total nitrogen, 5x TOC) and biofilm biomass (1.5x).
- Macroinvertebrate communities shifted, with reduced native chironomids and hydroptilids, and increased invasive species like Cheumatopsyche analis.
- Native goby densities were halved in invaded streams, where invasive poeciliids outnumbered native fish by approximately 8:1.
Conclusions:
- Invasive poeciliids negatively impact tropical stream ecosystem structure, function, and native species abundance.
- The widespread distribution of poeciliids necessitates increased public awareness to prevent further introductions.
- Effective eradication and restoration strategies are crucial for mitigating the ecological damage caused by invasive poeciliids.
Related Concept Videos
01:24Freshwater Microbial Ecology
67
Freshwater systems such as streams, rivers, and lakes exhibit distinct physical and biological characteristics that influence their microbial communities. These environments are broadly categorized into lotic systems—those with flowing waters like streams and most rivers—and lentic systems, which include still or slow-moving waters such as lakes, ponds, and marshes.In lentic systems, phytoplankton drive primary production, generating autochthonous organic carbon. In contrast, lotic...
67
02:17Ecological Succession
19.2K
Ecological succession is influenced by the processes of facilitation, inhibition, and toleration. Facilitation occurs when early successional species create more favorable ecological conditions for subsequent species, such as enhanced nutrient, water, or light availability. In contrast, inhibition happens when early successional species create unfavorable ecological conditions for potential successive species, such as limiting resource availability. In some cases, later successional species...
19.2K
01:39Keystone Species
20.9K
Measures of species biodiversity, such as richness (i.e., the number of species present) and evenness (i.e., their relative abundance), describe an ecological community’s structure. Many factors affect community structure, including abiotic factors (e.g., sunlight and nutrients), disturbances (e.g., fire or flood), species interactions (e.g., predation or competition), and chance events (e.g., foreign species invasion). Certain species—such as keystone species—also play a...
20.9K
02:26Ecological Disturbance
16.2K
An ecological disturbance is a temporary disruption in the environment resulting from abiotic, biotic, or anthropogenic factors, causing a pronounced change in an ecosystem. The impact of an ecological disturbance, which can depend on its intensity, frequency, and spatial distribution, plays a significant role in shaping the species diversity within the ecosystem.
16.2K
02:02Ecological Niches
22.4K
All organisms have a position within an ecosystem. The complete set of living and nonliving factors—including food resources, climate, and terrain—that define the position of a given organism are collectively referred to as the organism’s ecological niche.
22.4K
01:19What is Biodiversity?
28.1K
Biodiversity describes the variety of living things at multiple organizational levels: genetic, species and ecosystem diversity. Species diversity includes all branches of the evolutionary tree from single-celled prokaryotic organisms, bacteria, and archaea, to the eukaryotic kingdoms: plants; animals; fungi; and protists. To date, there have been about 1.75 million species identified, and new species are discovered every week.
28.1K