Almost everyone depends on trees in one way or another. They provide wood, food, shade, medicines and much more. Some of us have special connections with or important memories of trees. I remember a majestic, old oak tree on the property we lived on and climbing mango and breadfruit trees. Trees are also vital for many ecosystems. For example, they create forests and provide a home for many animals, plants and fungi. Because trees are so important, much information about them is available in online databases, published literature and herbariums. But how much information is available and how can we best use this information to better understand the world around us? We recently investigated these questions.
We were surprised at both how much and how little data there is when looking at different aspects of biodiversity. For more than 84% of all tree species, we found information about where they occur and their functional traits. Furthermore, the proportion of tree species for which biodiversity information was available was about 10% greater than that for plant species overall. This is impressive and shows that trees are a good model group for investigating biodiversity patterns. However, there are important gaps. For example, the most complete database on plant functional traits (TRY) did have data for more than 95% of all tree species, but only about half of these species (45%) had data available for traits other than the growth form being a tree and being woody, which by definition is true for all trees. Furthermore, limited data are available about the demography, ecological interactions, and socio-economic role of tree species.
So, what is the value of all these data? We can integrate the existing data and to identify and infer patterns and processes in trees and of biodiversity in general. Such information can be very useful for conservation. We looked at one of Australia’s most fascinating trees, the Australian Desert Oak (Fig. 1), Allocasuarina decaisneana (Casuarinaceae). This species often constitutes the only trees in the sandy desert environments of central Australia and starts out as feather-duster like seedlings (Fig. 2) that only start branching after the roots reach underground water sources. It defines the desert oak woodlands, which are considered a major vegetation subgroup (MVS 72). When we compared the occurrence records for the species with the mapped distribution of these woodlands, we found that MVS 72 likely occurs outside its mapped range.
Therefore, existing data on tree biodiversity is important information that can produce new scientific insights and help improve biodiversity conservation and management. Ideally, such biodiversity data would be readily and freely accessible to researchers and conservation practitioners alike. Having an easy-to-use platform to access this data would allow better-informed conservation decisions and could avoid duplication in data collection.
Futher reading: Keppel G, D Craven, P Weigelt, SA Smith, MT van der Sande, B Sandel, SC Levin, H Kreft & TM Knight (2021) Synthesizing tree biodiversity data to understand global patterns and processes of vegetation. J. Veg. Sci. 32: e13021.