Assessment of floristic diversity in the arid steppe region of Tiaret, Algeria

The study of plant diversity of the arid steppe regions is an important aspect of assessing their ecological and economical value and their need for conservation and rehabilitation in light of climate change today. The present study aims to determine the floristic diversity of three sites in the steppe region of Tiaret (Algeria) in terms of species and families present, phytogeographical aspects, and plant life forms using field observations carried out from 2010 to 2018. Overall, 245 plant species belonging to 175 genera and 53 families were recorded in the study region. The richest site in terms of biodiversity was Chot Ech-Chergui with 150 plant species belonging to 38 families, followed by the Massif of Nadhor with 130 species (37 families), then the Plateau of Ain Deheb with 121 plant species (31 families). The most frequent families recorded in these sites were: Asteraceae (17.96%), Poaceae (11.02%), and Fabaceae (7.35%). Shannon's diversity index analysis showed high diversity at the species level but low diversity in terms of plant families. The Pielou equitability index indicated significant evenness. In terms of Raunkier life-forms, therophytes (annuals and ephemerals) were predominant (37.69-49.59%) followed by chamaephytes (18.46-24.79%) and hemicryptophytes (14.67-17.69%). Mediterranean and Multi-regional species were the most frequent chorotypes contributing 50.20% and 33.23% of the total flora, respectively. Several North African endemic species were noted, namely Saccocalyx satureioides Coss. & Durieu, Carum foetidum (Coss. & Durieu) Maire, Tamarix boveana Bunge, Taraxacum getulum Pomel, Onopordum arenarium (Desf.) Pomel, Helianthemum apertum Pomel, Helianthemum hirtum (L.) Mill., Frankenia thymifolia Desf., Thymus algeriensis Boiss. & Reut., Thymelaea microphylla Meisn. and Pistacia atlantica Desf. Management programs are imperative to preserve the reported biodiversity and these fragile environments.