ARS Works to Mitigate Spread of Highly Invasive Water Hyacinth
As a highly invasive plant, water hyacinth can be deceptively beautiful. (Getty Images).
Though its lush green leaves and lavender flowers are deceptively beautiful, water hyacinth is a highly destructive threat that creeps along rivers and streams, eventually choking critical infrastructure. As one of the world’s most aggressive plants, water hyacinth clogs freshwater bodies, while cutting off fishing and boat passage. It also provides habitat for mosquitoes carrying diseases like malaria and dengue.
As part of ARS’ Area-Wide Pest Management Programs, Melissa Smith, a research ecologist at the Agricultural Research Service (ARS) Invasive Plant Research Laboratory, Fort Lauderdale, FL, has launched two projects focused on integrated weed management (IWM) approaches to reduce water hyacinth’s impact.
In a first for water hyacinth research, Smith’s team established 40 research plots in Florida’s Lake Okeechobee. Through these lake plots, they are tracking water hyacinth and native plant response to several IWM strategies, including biological control. Biological control, or biocontrol, aims to curb the population of invasive species by reuniting them with their natural “enemies,” like native insects.
In the case of water hyacinth, two weevils and a plant hopper (developed and released by ARS), can reduce water hyacinth biomass by 60 to 70% and flowering of the invasive plant by more than 90%. While this is helpful, water hyacinth remains problematic.
ARS researchers established plots in Florida’s Lake Okeechobee (shown here), for Integrated Weed Management and Biocontrol of the area where water hyacinth is prevalent. Creation of these “lake plots” is a first in water hyacinth research. (Google Earth satellite image).
Smith is testing approaches that integrate biocontrol with herbicides to increase efficacy, while reducing herbicide volume and frequency. Previous studies looking at IWM have been conducted in mesocosms (experimental water enclosures). “While mesocosm studies are important, they do not encompass all environmental processes,” she said.
Smith’s team is also developing multi- and hyper-spectral image technologies from drones and satellites.
“We’re developing multi-spectral and hyperspectral signatures, which is like having multiple cameras with multiple lenses,” said Smith. “Software can detect water hyacinth from images and differentiate it from other plants. It can also detect herbivores that feed on water hyacinth. We’re gathering the data from both satellite images and drones equipped with cameras. Once developed, this technology can be applied to other invasive plant systems or even agricultural pest systems.”
According to Smith, water hyacinth is much more damaging than many realize, debilitating agriculture, local environments, and fishing and shipping industries worldwide. It also impacts every continent except Antarctica.
“This is an international-level issue and it’s problematic for several reasons,” said Smith. “Water hyacinth lowers dissolved oxygen in the water, which has implications for fish populations, macroinvertebrates, and all the other community members within that aquatic ecosystem. It also outcompetes floating aquatic plants and rooted aquatic plants like native pond lilies and wetland systems, growing in the Florida Everglades.
“On the human side of things, water hyacinth impedes navigation from large shipping containers to small vessels, often isolating human populations,” Smith said.
The growth of water hyacinth impedes waterways. (Getty Images).
She added there is also a very strong link between water hyacinth, stagnant water, and Anopheles mosquitoes, which can carry mosquito-borne illness like malaria and dengue, causing significant harm to humans. – Tami Terella-Faram, ARS Office of Communications.