Evaluating, predicting and mapping belowground carbon stores in Kenyan mangroves.

Despite covering only approximately 138,000 km2, mangroves are globally important carbon sinks with carbon density values 3 to 4 times that of terrestrial forests. A key challenge in evaluating the carbon benefits from mangrove forest conservation is the lack of rigorous spatially resolved estimates of mangrove sediment carbon stocks; most mangrove carbon is stored belowground. Previous work has focused on detailed estimations of carbon stores over relatively small areas, which has obvious limitations in terms of generality and scope of application. Most studies have focused only on quantifying the top 1m of belowground carbon (BGC). Carbon stored at depths beyond 1m, and the effects of mangrove species, location and environmental context on these stores, is poorly studied. This study investigated these variables at two sites (Gazi and Vanga in the south of Kenya) and used the data to produce a country-specific BGC predictive model for Kenya and map BGC store estimates throughout Kenya at spatial scales relevant for climate change research, forest management and REDD+ (Reduced Emissions from Deforestation and Degradation). The results revealed that mangrove species was the most reliable predictor of BGC; Rhizophora muronata had the highest mean BGC with 1485.5t C ha-1. Applying the species-based predictive model to a base map of species distribution in Kenya for the year 2010 with a 2.5m2 resolution, produced an estimate of 69.41 Mt C (± 9.15 95% C.I.) for BGC in Kenyan mangroves. When applied to a 1992 mangrove distribution map, the BGC estimate was 75.65 Mt C (± 12.21 95% C.I.); an 8.3% loss in BGC stores between 1992 and 2010 in Kenya. The country level mangrove map provides a valuable tool for assessing carbon stocks and visualising the distribution of BGC. Estimates at the 2.5m2 resolution provide sufficient detail for highlighting and prioritising areas for mangrove conservation and restoration.

Evaluating historic graffiti based on cultural significance and definitions of art.

Many examples of historic graffiti have been shown to be worthy of attention and conservation. The examples discussed in this article have been selected for their previous academic study, enabling rational assessment. This work does not suggest that only those examples of historic graffiti that have been subject to academic investigation can be evaluated and classified. This article, the result of a collaboration between two individuals with complementary interests in building conservation and contextual studies in art and design, brings together formal techniques used in the assessment of cultural significance in traditional architectural conservation and established theories in the evaluation of art. It is the purpose of this work to help those who are attempting to evaluate the merit of graffiti to do so. The current Scottish system that assesses cultural significance may be incomplete in its evaluation of graffiti. This necessitates a supplementary investigation of the artistic characteristics and merit of graffiti. Almost all graffiti could be said to be 'art', using established definitions, but not 'good' art. This evaluation may only be undertaken by experts, as with other aspects of identification of cultural significance within the built environment.