The Editor’s Choice for issue 56:2 is written by Associate Editor, Alex Fajardo.  The selected article, Maintaining ecosystem properties after loss of ash in Great Britain by Louis Hill et al, focuses on the importance of using plant functional traits to predict potential changes to an ecosystem, following the loss of a key species.

In their study, Maintaining ecosystem properties after loss of ash in Great Britain, Dr. Louise Hill and colleagues aimed to respond to an increasingly common applied ecological problem: how to predict the most probable trajectories of a natural system when altered by a large-scale disturbance?  In this case, there are three protagonists in the story: common ash (Fraxinus excelsior) – the victim; and the emerald ash borer (Agrilus planipennis) beetle and the ash dieback-causing fungus, Hymenoscyphus fraxineus – the two aggressors.  You could in fact substitute the protagonists for others; you just need a natural or anthropogenic disturbance agent (e.g. landslides, pathogens, over-logging trees), and a victim (e.g. a forest, a watershed, a pond). This is especially important if the victim is a keystone species such as ash, whitebark pine or the jaguar.

canopy gaps due to ash dieback - louise hill
Gaps in the woodland canopy created by death of ash trees (photo by Louise Hill)

With an impressive data set at hand across whole of Great Britain, Hill et al. developed and applied an innovative analytic approach, Analytical Hierarchy Process (a tool borrowed from the social sciences), and used plant functional traits, which allowed them to predict changes in ecosystem properties due to ash loss (the ecology part), optimized by a hierarchy of traits’ importance. From this they could offer recommendations to managers and decision makers about how to avoid the disappearance of ash and the ecosystem services it provides.  Here, plant functional traits are essential in the link between biodiversity and ecosystem properties.

It is imperative to move from the idiosyncratic, species-specific responses of plants to changes in their milieu (be these global warming or over-logging) towards the trait-based approach, which has a more solid understanding of the system´s properties. The rationale here is that plant species with different traits may have different resource or habitat requirements. Another critical point of using the trait-based approach in these situations is that the ecological problem at hand can be modelled and therefore predictions can be made.  And this is exactly what Hill et al. did. Ultimately, they recommend different silvicultural practices (mixed-species forests) in different site locations to reach the optimal combination of ash conservation and ecosystem properties through the maintenance of several other species with specific traits.

This is applied ecology at its best and the study and the approximation used has the potential to be replicated elsewhere – I, for example, am thinking of using it to help determine resilience thresholds in temperate rainforest degradation in southern Chile.

The Editor’s Choice article, Maintaining ecosystem properties after loss of ash in Great Britain is free to read in issue 56:2 of Journal of Applied Ecology.

Read the authors’ own summary of the article here.