Grant: Discovery Grants Program - Individual

Ecosystem functions are essential for life on earth, and there has been a major research effort in past decades to determine the relationships between species diversity and ecosystem functioning. People construct ecosystems such as sewage treatment wetlands and green roofs to provide specific ecosystem services, but the relationships between the number of species in the ecosystem and performance of desired services has been little investigated. The proposed research will evaluate the role of increasing the number of plant species and different plant life-forms (grasses, succulents, shrubs etc.) in improving green roof performance. The ability for green roofs to provide services such as summer temperature reductions, winter temperature increases, carbon capture, stormwater retention and resistance to invasion by undesirable plants will be evaluated in replicated green roof microcosms. The traits of plant species and life-forms that optimally perform these different services will be assessed to determine the relationships between general plant traits and ecosystem functions. This will allow for selection of plants in many different regions to optimize green roof functioning. The benefits of increased plant biodiversity on roofs will only be sustained in the long-term if multiple species or life-forms can coexist without being outcompeted. We will determine whether the species that perform optimally on green roofs can coexist stably, and determine the mechanisms that allow such coexistence. While species differences are essential for biodiversity to enhance ecosystem functioning, recent ""neutral models"" suggest that such differences are not required for long-term coexistence of species. We will investigate whether the degree to which species coexistence is governed by mechanisms that rely on species differences. This research will result in tangible improvement to green roof performance that will in turn lead to energy and economic savings.