Vegetation in stormwater practices affects natural processes and can provide a variety of ecosystem services. This page provides a summary of these processes and services and includes numerous links to additional information.
There are an almost uncountable variety of pollinators that are highly beneficial to the functioning of an ecosystem. Pollinators and insects help promote vegetation establishment, growth, and long-term vegetation survivability. Considerations of vegetation selection and insect/pollinator interaction are highly encouraged when designing landscaping and building green infrastructure. Extensive research has been done into pollinators give their place as a key ecosystem group of species that has proven to be instrumental in ecosystem cascading.
Bees are a vital and keystone species to the long-term stability and sustainability of our ecology. Bees provide multiple benefits such as pollination, medicinal, food, and seed dispersal. It is estimated that there are about 400 different species of bees are in Minnesota. These bees are among many of the pollinators and insects that are beneficial to vegetation.
It is highly encouraged to take into consideration design methods that will attract pollinators and insects and help them thrive and grow. Additionally, soil compaction during construction should be taken into consideration as well as because ~70% of bee species are ground nesting. Tightly packed soils will not allow proper establishment of vegetation and prevent colony establishment for insects and pollinators that make their habitats in soil. Additionally, vegetation considerations should be focused on the feeding, above ground nesting, or sheltering for these species that access ground space through vegetation stems.
The presence of birds can signify a healthy and robust ecosystem. Birds provide a vital ecosystem service that can help determine the success or failure of a site when it comes to vegetation and wildlife.
Birds are important to vegetation design for a variety of reasons. The presence of birds can promote cross pollination, fertilize plants, increase soil fertility, act as insect control, rodent control, and other wildlife control. They add beauty to nature with their colorful songs and plumage while some provide for the removal of dead animals.
When designing vegetation for bird use, consider what types of birds you would like to attract, the type of vegetation needed to attract their food source, and if human use of the site will have an impact on survivability. The use of chemicals to stabilize or grow plants can be detrimental to wildlife and inadvertently prevent bird propagation.
The presence of birds helps in a variety of ways, such as:
Cross pollination, movement of gametes, fertilize plants, increase in soil fertility, insect control, some birds eat rodents, some eat snakes, eat fish, seed propagation, beauty in nature, removal of dead animals
Amphibians provide multiple benefits to a constructed ecosystem. They can operate as an ecosystem indicator, provide insect and pest control, and provide services to help clean water quality when plants they eat regrow. With up to 40% of amphibians classified as endangered, creating minor adjustments to ecosystem designs can create opportunities for this wildlife to thrive. Other animals also rely upon amphibians as a prey and the addition or removal of plants that sustain amphibians can mitigate or promote this effect.
Amphibians are sensitive to their surrounding environments. Toxic chemicals associated with urban development can alter their ability to survive and thrive. Chemistry, pH, and temperature of urban runoff may negatively impact amphibians. Amphibians also experience increased mortality due to crossing impervious surfaces. Consideration and selection of vegetation can help protect the ecosystem’s ability to sustain amphibians.
Amphibians provide multiple benefits. They can operate as an ecosystem indicator, provide insect and pest control, and provide services to help clean water quality through plants they eat. With up to 40% of amphibians classified as endangered, creating minor adjustments to ecosystem designs can create opportunity for this wildlife to thrive. Other animals also rely upon amphibians as a prey and the addition or removal of plants that sustain amphibians can mitigate or promote this effect.
Amphibians are sensitive to their surrounding environments. Toxic chemicals associated with urban development can alter their ability to survive and thrive. Chemistry, pH, and temperature of urban runoff may negatively impact amphibians. Amphibians also experience increased mortality due to crossing impervious surfaces. Consideration and selection of vegetation can help protect the ecosystem’s ability to sustain amphibians.
Beneficial vegetation the improves water quality, removes nutrients, stabilize pH, prevents excessive siltation and provides desirable shade and protection for amphibians should be considered. Amphibians like damp, dark areas that have controllable access points with them. Consideration of using rock formations in conjunction with vegetation should be considered. Vegetation that also attracts food sources such as mosquitoes, worms, mice, and any other small creatures that can fit into an amphibians mouth is beneficial to amphibian populations.
Below is a list of additional reading, including stormwater design considerations.
Human use of green spaces is the primary focus that many designers focus on. When designing a landscape that will be occupied by humans it is advised that the space take into consideration species of wildlife that can cohabitate/exist alongside humans to ensure that the environmental impact of the build is minimized.
Human impact on green spaces has a wide variety of impacts. Water quality and soil compaction are two of the most concerning activities when it comes to establishing vegetation. Unintended human use after seeding, planting, or grading can significantly alter the landscape and prevent successful vegetation establishment. Water quality from human use is also significant as the more pollutants introduced into the water is a significantly limiting factor for what types of plants will be successful in the vegetation plan.
The downstream effect is a common design consideration that is missed as well. The impact of stormwater and vegetation isn’t just an isolated system that only impacts the area that it is developed on; the design also has downstream consequences if there are pollutants introduced to a water source if they are not filtered, treated, or distanced far enough away.
Different landscapes can achieve desirable interactions with humans and provide the aesthetic pleasantries that humans enjoy such as rain gardens, water detention/retention systems, reuse irrigation systems, and wildlife habitats. Recreational purposes and drinking purposes are other uses that should be taken into consideration with how humans will interact with the area.
Consideration of the application of stormwater vegetation systems is highly encouraged. Design considerations involving cisterns, rain barrels, groundwater table, distance from water sources, erosion control blankets, impermeable liners, among others should be thought of to see if the onsite vegetation can be self-sustaining and minimize the impact between vegetation and the way humans use the landscape.
The construction of urban structures can cause major changes in the temporal and spatial make up of water systems. This can lead to increased peak flows, decreased minimum flows, increased flow variability, higher flood rates, and warmer temperatures in the summer and decreased temperature in the winter.
Wildlife and aquatic species use conveyance systems to move around areas and they are all interconnected through a food web. These conveyance systems have a major impact on the surrounding region through the provisioning services, regulatory services, supporting services, and cultural services that they affect. This should be taken into consideration as ecosystem collapse, unintended alterations, or undesirable conditions may develop if these considerations aren’t planned for.
Water conditions desired should be established and during this time frame it is important to determine what sort of pollutant load the vegetation and incoming stormwater will be exposed to. Phosphorus and nitrogen are two compounds that should be accounted for during selection of aquatic species as their tolerance to these nutrients may be required to properly establish a feasible vegetation plan. Alterations can also impact the sediment and nutrient loads, local food webs, pesticides, contaminants, local aquatic habitats, species assemblages, ecosystem processes.
When designing for aquatic species a survey of the surrounding area is strongly recommended to determine what sort of environmental stressors are applied to that zone. Some examples are wastewater treatment plants, industrial discharges, storm sewers, septic systems, lawns, gardens, roads, nearby vegetation and parking lots. Local wildlife will be attracted to this area as well and should be considered when selecting aquatic species.