Residential and lower-density housing landscapes are rapidly expanding, possibly comprising greater than 26% of total US land cover. Despite the increasing commonality of these landscapes, not enough is known about their general ecology and management. For instance, the expansion of residential landscapes alters ecological spatial patterns via fragmentation and habitat loss. Strategies are required to restore the ecological functions and services that these lost habitats once provided. Designer and engineered ecosystems such as ornamental gardens and stormwater ponds are placed throughout urban and residential landscapes to provide important functions, including recreation, enhanced aesthetics and property value, and the protection of water resources. These anthropogenic ecosystems, if designed, constructed, and managed properly, may also provide at least a portion of the ecological functions and services lost to initial development. Such an approach acknowledges the conservation value that even small, fragmented pieces of land can have and the potential to enhance ecosystem services and functionality via the manipulation of species composition.
Results/Conclusions
Here, we describe the potential for designer and engineered ecosystems to provide important ecosystem services and functions within residential landscapes, using ornamental gardens and stormwater ponds (SWPs) of Florida, USA as case studies. Ornamental gardens provide multiple ecosystem services to residential landscapes (e.g. enhanced biodiversity, cooling, aesthetics). However, their plants are vulnerable to arthropod pests that limit these services. A regional field investigation of ornamental gardens in residential communities of north-central Florida revealed evidence that designing gardens with more dense plantings can decrease the abundance of these pests, and that increasing plant alpha diversity can increase the abundance of arthropod predators that feed on these pests.
Regarding stormwater ponds (SWPs), these engineered ecosystems limit stormwater and pollutant runoff from developed landscapes into nearby natural water bodies. We have identified over 95,000 SWPs in Florida alone, forming a potential network for species movement among cities. We also found that SWPs harbor a diversity of invertebrates whose community composition varies relative to plant community structure, i.e. a component of SWPs heavily managed by humans.
These case studies suggest that manipulating plants in ornamental gardens and SWPs can promote the services of pest resistance and biodiversity. Nevertheless, we also found that ornamental gardens serve as sources of, and SWPs as habitat for, many invasive plant species. These disservices need consideration when developing strategies to maximize the benefits of designer and engineered ecosystems in residential landscapes.