Seed banks and emergent vegetation of temporary freshwater rock pools

Abstract

Temporary freshwater rock pools are important ecosystems having large species diversity. They form karstic hollows on limestone rocks mostly by solution processes. This study focused on the seed banks and emergent plant communities found in two areas; San Pawl tat- Targa and Qala, Gozo. The study period was between October and March 2009, therefore a whole wet season was studied. The vegetation of these pools includes a wide range of both common and rare species. The emergent flora is derived from seeds found in the seed bank. However the seed bank is not always a good indication of the emergent flora. The seed data indicated low species richness; however the emergent vegetation was quite rich. Some causes leading to this result might have been various; predation is one of them. The main vegetation varied between the two locations. While the most common flora for San Pawl tat- Targa were Elatine gussonei, Chara vulgaris, Ranunculus saniculifolius and filamentous algae the most dominant species in Qala were Crassula vaillantii, Lythrum hyssopifolia and Sedum caeruleum. Another remarkable result regarding the flora found in these rock pools was that vegetation is likely to be more abundant during winter months. However in some of the rock pools in San Pawl tat- Targa species such as filamentous algae experienced an increase during late winter and beginning of spring time.