Conservation biology assessment of the Wardija areas scheduled for protection by MEPA

Abstract

Around the Maltese Islands, woodland habitats are rare with only few remaining remnant Quercus ilex woodlands. Il-Ballut tal-Wardija is one of the last remaining woodlands that has survived for more than 400 years. In 2008, MEPA declared this area as well as those areas surrounding it as an Area of Ecological Importance and one of the NATURA 2000 sites under the habitats directive. This study aimed to gain a better understanding of the diversity supported by the habitats present in this woodland. Such results can be compared to those obtained from similar studies conducted Internationally. The diversity assessment study incorporated sampling techniques for flora and fauna populations within the woodland. The overstorey vegetation was sampled using a fixed-plot method whilst the average % abundance for undergrowth vegetation was measured using a belt transect. A combination of pitfall traps, random soil quadrats, and random under stone searches were used to sample the heterogeneity of the soil and leaf litter layer. Canopy diversity was also included with point transect surveys used to measure avian populations within the woodland. Another technique used involved random tree searches so as to better understand the communities that inhabit trees. The nocturnal activity within the woodland was also sampled during the spring season using light traps for nocturnal insects and acoustic bat surveys. The results obtained show that the overall composition of the woodland diversity is similar to that of other Mediterranean climate countries. Quercus ilex is the dominant species in the overstorey vegetation with a wide variety of DBH measurements ranging from 25cm to 205cm. With soil fauna abundances, Kruskal Wallis and One-Way ANOVA results show that certain differences in the spatial and temporal distribution are present. With the order Glomerida, significant differences were seen in the mean abundance between seasons as well as between the areas sampled (p<0.05). Other orders displayed significant differences in mean abundance due to seasonality changes. The order Pulmonata displayed a significantly higher abundance during the winter season when compared to that of spring (p<0.05). The tree searches results show that abundance for most of the orders are not different between the two woodland patches. Although natural effects can be held responsible for certain significant differences, the possibility of anthropogenic effects also being accountable cannot be discarded. The study ends with a short list of recommendations that aim to help better the conservation measures that are currently in place.