Over the last few decades, stormwater ponds have become increasingly utilized to manage runoff from urban landscapes, acting as a key hydrological filter between cities and surrounding natural waterbodies. Additionally, the unique habitat provided by these engineered ecosystems is often colonized by a variety of plants and animals, which can then disperse into nearby streams, rivers, and lakes. This potential for stormwater ponds to export organisms from urban into natural areas is particularly concerning given that the characteristics of these ponds (i.e. association with human activities, nutrient-rich, often disturbed) are common drivers of species invasion. Despite the likely widespread and increasing usage of stormwater ponds in urban watersheds, we currently do not know their quantity or distribution, their degree of invasion, nor what pond characteristics affect invasion. For example, stormwater ponds can be designed as permanent (‘wet’) or temporary (‘dry’) waterbodies. Ponds are also often landscaped for aesthetic purposes by businesses and homeowner associations. These characteristics of pond design and management could subsequently affect opportunities for invader establishment. Using Florida as a study system, we examined statewide stormwater pond coverage and conducted a survey of invasive plant occurrence across a variety of pond types.
Results/Conclusions
We identified over 95,000 stormwater ponds that have been built throughout Florida, concentrated in urbanized areas and along roads. These ponds are now a major component of urban land cover, similar to industrial, institutional, or commercial land types. Additionally, in a subset of 30 surveyed ponds, we determined that 96% contained at least one invasive plant species with 28 total invasive species identified across all ponds. The degree of invasion also varied depending upon pond design, management, and nutrient levels. Our results highlight how rapid development can drive the widespread construction of engineered ecosystems, which can harbor a wide diversity of invasive species. The next steps of our research will examine how pond vegetative structure and water chemistry affects benthic invertebrates, and the traits that drive invasive plant occurrence across these habitats. Stormwater ponds, along with other engineered ecosystems, will continue to be built as urbanization progresses. Their ubiquitous usage and likely ongoing proliferation necessitate that we understand their potential to contribute both positively (e.g. biodiversity) and negatively (e.g. invasive species) to urban watersheds.