Addressing indicators for geoheritage monitoring based on degradation risk and scientific value quantitative assessment

Keywords: monitoring, criteria, degradation, geoheritage, Vale de Meios, Portugal

Monitoring is one of the main stages in geoconservation strategies, essential to guarantee
geoheritage sustainability. Nevertheless, few studies focus on geoheritage monitoring techniques
and methods, unlike the multitude of works focusing on procedures to inventory and assess the
value of geosites. Moreover, criteria used in these methods can be applied on monitoring
procedures, specifically those supporting degradation risk and scientific value quantitative
assessments. In this context, a geoheritage monitoring model is being applied in Vale de Meios
(Alcanede, Portugal), an abandoned limestone quarry with well-preserved Middle Jurassic
Theropod footprints, inside the Serras de Aire e Candeeiros Natural Park. This geosite was
previously assessed for its scientific value and vulnerability and it is included in the Portuguese
inventory of geoheritage with national and international relevance. A set of “scientific value” and
“degradation risk/vulnerability” criteria were reviewed to assess the degradation of the geosite
and used to identify the most suitable monitoring model. The “integrity” criterium used in most
methods to assess the scientific value of geosites, also credited as “conservation status”, is strictly
connected with the deterioration of the geoheritage elements in the past and present, while
degradation risk is normally referring to the threats and potential losses in the future. Fourteen
“degradation risk” assessment sub-criteria (intrinsic active processes, deterioration of geological
elements, size, extrinsic active processes, proximity to active processes, economic potential,
collectible elements potential, protection status, proximity to human activities, accessibility,
population density, visitor facilities, degradation by public use, and visitation control) can be
distributed by the main criteria fragility, natural vulnerability, anthropic vulnerability, and public
use. A detailed analysis of the criteria and the specific characteristics of each geosite support the
definition of suitable monitoring indicators. In the Vale de Meios geosite, monitoring actions
should primarily consider: active natural process, deterioration of geological elements,
accessibility, visitor facilities, degradation by public use, and visitation control in order to define
the monitoring indicators. An analysis of the conservation status over the past decades has been
carried out, using time indicators of deterioration. Long-term monitoring results will provide more
data about the geoheritage degradation though partial data show that in Vale de Meios the main
concern is related with the high natural vulnerability of the Theropod footprints, which are
exposed to natural erosion. Despite the protection status of the area and design of a plan for
visitation control measures, conservation procedures should prioritize physical protection
initiatives in the geosite management strategies.