Applications of the IUCN Red List in evaluating global extinction risk of timber tree species.

Abstract

Anthropogenic deforestation and habitat degradation are major pressures on biodiversity. The world’s wild-growth timber tree species additionally face pressure from unsustainable and illegal harvest practices. Despite the threats to these economically valuable species, our understanding of their extinction risk remains incomplete and outdated. In fact, many timber tree taxa are marketed under trade names only, making it difficult to identify those most at risk. An additional challenge is presented by limited data and the pressing need for rapid species assessment in order to inform conservation actions. However, the use of ‘big data’ is coming to the fore in ecological research, and offers a valuable chance to meet international assessment targets such as those of The Global Strategy for Plant Conservation (GSPC), which call for knowledge of the conservation status of all known plant species to guide conservation actions (GSPC Target 2), in addition to sustainable harvesting of all wild- sourced plant-based products (GSPC Target 12), by the year 2020 (CBD, 2012). This thesis therefore aimed to identify timber tree taxa in trade at the species level; to assess utility of occurrence records from the Global Biodiversity Information Facility (GBIF) in timber species range mapping; to assess current extinction risk of a priority subset of timber tree species by applying the IUCN Red List (Red List) of Threatened Species Categories and Criteria; and, lastly, to evaluate the uncertainty of these preliminary Red List assessments. Consolidation of open-access timber lists produced a ‘working list’ of 1,578 angiosperm timber taxa in trade. GBIF records were demonstrated to be a suitable low time-cost resource with which to estimate species extent of occurrence and prioritise range-restricted timber tree species for Red List assessment. In addition to GBIF datasets, Global Forest Change (GFC) satellite imagery was found to be a valuable resource for assessing timber tree species range size, habitat fragmentation, and population trends over time. Preliminary Red List assessments conducted for 324 timber tree species suggest that some 69% may be threatened with extinction if current rates of deforestation persist. Although GBIF and GFC ‘big data’ were found to introduce some uncertainty into timber tree Red List categorisations, quantitative comparison to assessments conducted using ‘expert’ datasets suggested that categorisations were not greatly impacted. Furthermore, these evaluations illustrated the scarcity and inaccessibility of more traditional sources of Red List assessment data for timber tree species. It is evident that if we are to meet GSPC and other conservation targets for timbers and other at-risk, poorly-known tree taxa, we must recognise that open-access ‘big data’ repositories represent a powerful opportunity for Red Listing.