Global geodiversity components are not equally represented in UNESCO Global Geoparks

Abstract

The aim of UNESCO Global Geoparks (UGGs) is to protect globally significant geoheritage and geodiversity, but quantitative evidence on the global representativeness of geodiversity components (i.e. geology, soils, geomorphology and hydrology) in these geoparks is in short supply. Here, we provide a first assessment by deriving a global map of geodiversity to test whether the presence of geodiversity components in UGGs is representative for the global availability and distribution of geodiversity. Using openly accessible global datasets and a newly developed workflow, we have calculated metrics for each geodiversity component and a global geodiversity index; we then quantified whether UGGs represent global geodiversity and then compared their components to a randomized spatial distribution of geoparks. Our results show that lithological and topographical diversity are more represented in UGGs than outside these sites, while soil type and hydrological diversity are not significantly different. Furthermore, individual soil types and lithological classes are under-represented and unevenly distributed in Asian and European UGGs. This is probably caused by the concentration of geoparks in Asian and European mountains. To better conserve geodiversity, we suggest an initiative to consider the protection and representation of all geodiversity components in their global context. This article is part of the Theo Murphy meeting issue 'Geodiversity for science and society'.

Keywords: UNESCO Global Geoparks; geoconservation; geodiversity mapping; global geodiversity; protected areas.

Figure 1.

Global distribution of 147 UGGs used for the analysis. Two clusters occur, one in Asia (61) and one in Europe (74). (Online version in colour.)

Figure 2.

Workflow for comparing global, Asian and European geodiversity (component) scores in and outside UGGs. The workflow has four routines: 1. Preprocessing of global layers, 2. Geodiversity metric and component calculations, 3. Index calculations and 4. Statistical analysis. Input layers are indicated in parallelograms.

Figure 3.

Global distribution of geodiversity. (a) Global geodiversity index, (b) lithology diversity index, (c) soil diversity index, (d) topographical diversity index and (e) hydrological diversity index. For visualization and comparison purposes, all data are presented in five classes (1. very low, 2. low, 3. moderate, 4. high, 5. very high) using a Jenks natural-breaks classification.All maps are available for download via figshare: https://doi.org/10.21942/uva.23496923. (Online version in colour.)

Figure 4.

Boxplots displaying the distribution of total geodiversity and geodiversity metrics within UGGs and outside geoparks (in randomly selected polygons), separately shown for a global, Asian and European extent.(a) Total geodiversity and (b–g) individual geodiversity metrics (see details in table 1). ^* Indicates that the metric is significantly higher (corrected p < 0.05) in UGGs then in the random samples for all 100 comparisons. An overview of the percentage of corrected p < 0.05 for each metric is available in electronic supplementary material, table S3. For visualization purposes, the data of all 100 random sampling repetitions are shown together in one boxplot.