Applying trait-based models to achieve functional targets for ecological restoration
The restoration of degraded ecosystems is one of the greatest environmental challenges of the 21st Century and often involves manipulating indigenous ecological communities to achieve functional targets. The response-and-effect trait framework lays the conceptual groundwork for translating restoration goals into functional trait targets by unifying the mechanisms of community assembly with biodiversity effects on ecosystem functioning. However, quantitative frameworks have been lacking for translating functional trait targets into assemblages of species that practitioners can actually manipulate. This talk will describe new quantitative trait-based models that can be used to generate experimental communities to test theories about which traits, which trait values, and which species assemblages will be most effective for achieving functional targets. The first model uses systems of linear equations and is an adaptation of Shipley’s CATS model. The second model applies Bayes Theorem and Monte Carlo integration to obtain a range of species abundances that meet specified trait distributions. The quantitative frameworks introduced in this talk are applicable to any restoration project that includes the manipulation of biotic community composition in order to achieve quantifiable functional targets.
Three examples illustrate how the frameworks can be used to generate assemblages of indigenous species by applying ecological theories to achieve functional targets and restoration goals. First, we can apply the theory of environmental filtering to restore forest resiliency in the face of climate change by deriving assemblages of species that have trait values that will promote survival under a changing climate. Second, we can apply competition theories, such as limiting similarity or competitive hierarchies, to derive assemblages of native species to control and exclude non-native invaders. Third, we can apply the mass ratio or niche complementarity theories to derive assemblages that will influence ecosystem processes in specified ways. These frameworks are generalizable, flexible tools that can be widely applied across many terrestrial ecosystems to confront some of the most pressing ecological challenges of our time, but there is still much to be learned about which specific trait target values will achieve our functional objectives. The application of these models within experimental contexts will bring us closer to achieving our goals. A trait-based framework provides restoration ecology with a robust scaffold on which to apply fundamental ecological theory to maintain diverse functioning ecosystems in a rapidly changing world.