Using airborne lidar to characterize North European terrestrial high-dark-diversity habitats

Abstract

A key aspect of nature conservation is knowledge of which aspects of nature toconserve or restore to favor the characteristic diversity of plants in a given area.Here, we used a large plant dataset with>40 000 plots combined with airbornelaser scanning (lidar) data to reveal the local characteristics of habitats having ahigh plant dark diversity—that is, absence of suitable species—at nationalextent (>43 000 km2). Such habitats have potential for reaching high realizeddiversity levels and hence are important in a conservation context. We calcu-lated 10 different lidar based metrics (both terrain and vegetation structure)and combined these with seven different field-based measures (soil chemistryand species indicators). We then used Integrated Nested Laplace Approximationfor modelling plant dark diversity across 33 North European habitat types(open landscapes and forests) selected by the European communities to beimportant. In open habitat types high-dark-diversity habitats had relatively lowpH, high nitrogen content, tall homogenous vegetation, and overall relativelyhomogenous terrains (high terrain openness) although with a rather highdegree of local microtopographical variations. High-dark-diversity habitats inforests had relatively tall vegetation, few natural-forest indicators, low potentialsolar radiation input and a low cover of small woody plants. Our results high-light important vegetation, terrain- and soil-related factors that managers andpolicymakers should be aware of in conservation and restoration projects toensure a natural plant diversity, for example low nutrient loads, natural micro-topography and possibly also open forests with old-growth elements such asdead wood and rot attacks.