The value of indicator species for landscape characterization

Abstract

Given that different types of landscape are affected by different environmental factors, is it possible to identify plant species indicative of these landscape types? An analysis of indicator species was made using 140 vegetation samples distributed over five landscape types. A total of 30 indicator species were identified, displaying varying indicator value. The variation disclosed the existence of a gradient between landscape types in terms of the prevailing ecological conditions. The analysis of the results also led to a reflection on the hierarchical level of which species are indicative (landscape vs. ecosystem). Further 20 samples were taken to check the validity of the indicator species. The identification of the indicator species present in these samples enabled each sample to be assigned to one of the landscape types; that assignment was subsequently checked against the actual landscape from which samples were taken. Seventy-five percent of the 20 validation samples were correctly assigned; the misassignment of the remaining 25% was due largely to the heterogeneous nature of the landscapes. On the basis of these results, we concluded that it is possible to characterize landscapes on the basis of indicative plant species, although characterization becomes more incomplete as the internally heterogeneous nature of the landscape increases.