Physiognomy as a basis for plant species conservation in urban areas : Beirut as a case-study -

Abstract

The Lebanese coast is rich in plant diversity and is simultaneously highly urbanized. This makes the conservation of endemic coastal plants very challenging. Semi-natural open urban spaces harboring remnant patches of endemic plants are being destroyed and re-designed to offer managed open spaces that do not consider plant conservation and do not seek to incorporate native species. In this study, commonly used vegetation description methods were applied in built areas as well as semi-natural and managed urban spaces, with the aim of assessing the growing requirements of native coastal plant species. Case study species were selected following a revision of the literature to identify plant species that are endemic to the Lebanese coast, and that may be at high risk of extinction. Three such species were identified: Limonium mouterdei, Limonium postii, and Matthiola crassifolia. Field surveys of these three species in their historic locations were conducted between 2011 and 2015. Field investigations revealed that L.mouterdei is still found in only one site in Beirut. Limonium postii was found in 7 out of 8 reported locations in Lebanon whereas M. crassifolia was found in 4 out of the 5 previously reported locations. Red listing of the target species revealed M. crassifolia is Endangered (EN), L. mouterdei is Critically Endangered (CR), and L. postii is Endangered (EN). Given that the three target plant species co-occur in a restricted area in Beirut, Lebanon’s most urbanized coastal city, Beirut was selected as the case study location. Field surveys in the study location revealed the presence of both Limonium mouterdei and L. postii in one patch area and M. crassifolia in 73 patches. Quadrats were set in selected patches to collect physiognomic, floristic, and environmental data on the three target species. Physiognomic findings revealed that M. crassifolia was highly associated with several perennial life-forms including tuft trees, low lying creeping succulents, caespitose dwarf-shrubs an