2023 HARPER PRIZE SHORTLIST: Throughout March, we are featuring the articles shortlisted for the 2023 Harper Prize. The Harper Prize is an annual award for the best early career research paper published in Journal of Ecology. Tyler Coverdale’s article ‘Unravelling the relationship between plant diversity and vegetation structural complexity: A review and theoretical framework‘ is one of those shortlisted for the award:

👋 About Tyler

Tyler grew up outside Cleveland, Ohio (USA), but his love of nature was fostered by annual family trips to the montane ecosystems of Rocky Mountain National Park in Colorado. He intended to major in history at the beginning of his undergraduate studies (Brown University), but discovered ecology early on and soon became immersed in field research. Tyler’s early research focused on the causes and consequences of cordgrass die-off in New England salt marshes, before shifting to the effects of large herbivore extinction on African savanna plants during his PhD (Princeton University). After this, Tyler did postdoctoral research on plant chemical ecology at Cornell University and savanna vegetation structure at Harvard University. Currently, Tyler is an Assistant Professor in the Department of Biological Sciences at the University of Notre Dame in South Bend, Indiana USA. Research in Tyler’s lab focuses on the ecology, evolution, and conservation of plant communities in African savannas and Midwest US prairies.

🔎 About the shortlisted paper

Structurally complex habitats tend to support more biodiverse communities, a pattern notably demonstrated by MacArthur and MacArthur (1961). Vegetation structural complexity—the three-dimensional distribution of vegetation in an ecosystem—also affects a number of other important ecological patterns and functions, including microclimate regulation, animal movement, and ecosystem productivity. As such, restoration of vegetation structure has been identified as a potentially useful management tool, particularly for habitats that have been homogenized by human activity. Identifying the best approach(es) for increasing or maintaining structural complexity hinges on understanding the relationship between plant community composition and physical structure. In this context, our study demonstrated that the biodiversity-structural complexity relationship tends to follow classic biodiversity-ecosystem function patterns, and specifically that more diverse plant communities tend to be more structurally complex.  

Using data from 29 studies that used active remote sensing to quantify vegetation structure, we found that vegetation structural complexity was nearly always higher at sites with greater plant diversity. For a subset of these studies that measured complexity across multiple levels of plant diversity, we showed that positive biodiversity-structural complexity relationships were most often positive and saturating (with all others increasing linearly), suggesting that there is at least some functional redundancy in species’ contributions to structural complexity. These results suggest that the restoration of biodiversity and vegetation structure are compatible management goals, and that they can be simultaneously achieved by facilitating the establishment and persistence of diverse plant communities.

🌳 What’s next?

Among other topics in plant community ecology, research in my lab continues to investigate the relationship between plant diversity and structural complexity. To this end, we recently paired high-resolution LiDAR data with long-term plant composition data from a long-term savanna herbivore exclosure study. Consistent with the results of our review (which included almost exclusively forest ecosystems), we found that more diverse savanna plant communities tend to be more structurally complex. However, in this particular savanna ecosystem the relationship between plant diversity and structural complexity was strongly shaped by the identity and abundance of large mammalian herbivores. Overall, plant diversity and structural complexity decreased with increasing herbivory pressure, but the herbivores responsible for these changes were different for the overstory and understory plant communities: elephants and giraffes had the strongest effects on the diversity and structure of the tree layer, while smaller-bodied species like impala and dik-dik had comparable effects in the short-statured herbaceous layer. The impacts of herbivores on vegetation structure appear to be driven by a combination of factors, which include effects on plant community composition and the physical structure of individual plants.

Find Tyler on X and on his website. 

Read the full list of articles shortlisted for the 2023 Harper Prize here.