Assessment of plant diversity of endemic species of the Saharo-Arabian region in Egypt

Savanna, semi-deserts, and hot deserts characterize the Saharo-Arabian region, which includes Morocco, Mauretania, Algeria, Tunisia, Libya, Egypt, Palestine, Kuwait, Saudi Arabia, Qatar, Bahrain, the United Arab Emirates, Oman, Yemen, southern Jordan, Syria, Iraq, Iran, Afghanistan, Pakistan, and northern India. Its neighboring regions, the Sudano-Zambezian region belonging to the Paleotropical Kingdom and the Mediterranean and Irano-Turanian regions included in the Holarctic Kingdom, share a large portion of their flora with the Saharo-Arabian region. Despite the widespread acknowledgment of the region's global importance for plant diversity, an up to date list of the Saharo-Arabian endemics is still unavailable. The available data are frequently insufficient or out of date at both the whole global and the national scales. Therefore, the present study aims at screening and verifying the Saharo-Arabian endemic plants and determining the phytogeographical distribution of these taxa in the Egyptian flora. Hence, a preliminary list of 429 Saharo-Arabian endemic plants in Egypt was compiled from the available literature. Indeed, by excluding the species that were recorded in any countries or regions outside the Saharo-Arabian region based on different literature, database reviews, and websites, the present study has reduced this number to 126 taxa belonging to 87 genera and 37 families. Regarding the national geographic distribution, South Sinai is the richest region with 83 endemic species compared with other eight phytogeographic regions in Egypt, followed by the Isthmic Desert(the middle of Sinai Peninsula, 53 taxa). Sahara regional subzone(SS1) distributes all the 126 endemic species, Arabian regional subzone(SS2) owns 79 taxa, and Nubo-Sindian subzone(SS3) distributes only 14 endemics. Seven groups were recognized at the fourth level of classification as a result of the application of the two-way indicator species analysis(TWINSPAN) to the Saharo-Arabian endemic species in Egypt, i.e., Ⅰ Asphodelus refractus group, Ⅱ Agathophora alopecuroides var. papillosa group, Ⅲ Anvillea garcinii group, Ⅳ Reseda muricata group, V Agathophora alopecuroides var. alopecuroides group, Ⅵ Scrophularia deserti group, and Ⅶ Astragalus schimperi group. It's crucial to clearly define the Saharo-Arabian endemics and illustrate an updated verified database of these taxa for a given territory for providing future management plans that support the conservation and sustainable use of these valuable species under current thought-provoking devastating impacts of rapid anthropogenic and climate change in this region.

Notes on the key role of stenochoric endemic plants in the floristic regionalization of Yunnan

With the accumulation and accessibility of information about plant species,it is time to re-evaluate and further divide a global biodiversity hotspot region,Yunnan,located in southwestern China.In this study,we combined data on the distribution of 1010 stenochoric endemic seed plants,vegetation constitution,geological history and climate change,and used these to propose a new system of floristic regions.We identified 11 distinct floristic subregions and 84 floristic provinces within Yunnan.Our work confirmed some views emphasized by Wu Zhengyi that the stenochoric endemic species play a key role in defining floristic provinces;that stenochoric endemic plants with long collection and publication histories are more valuable;that greater attention should be paid to woody plants;and that for Yunnan,a border region,some trans-border distributed elements should be treated cautiously.

The role of the pollination niche in community assembly of Erica species in a biodiversity hotspot

Aims Closely related species frequently co-occur in plant communities.The role of niche partitioning for allowing their coexistence has been called into question,but most studies on community ecol-ogy neglect pollination as a niche component,and thus poten-tially underestimate niche partitioning.Here,we investigate the importance of the pollination niche for determining coexistence in a biodiversity hotspot.We specifically test whether co-flowering insect-pollinated species of Erica,the most species-rich plant genus of the South African Cape Floristic Region,are characterized by dif-ferent functional floral traits and different specialized pollination systems.Methods Communities of co-flowering Erica species were studied at three sites in the fynbos biome in the Western Cape of South Africa.We focused on five species with flowers that conform to an insect pol-lination syndrome.We assessed whether floral traits important for pollinator attraction and mechanical fit overlap by comparison of scent(gas chromatography coupled with mass spectrometry),col-our(spectrophotometry and models of bee vision),nectar volume and concentration and corolla morphology.Pollinator partitioning was quantified by comparison of floral visitor profiles and pollinator importance,calculated as the product of visitation rate,number of flowers probed per visit and pollen load for each functional visitor group among species within communities.Potential effects of com-petition were assessed by comparing visitation rates both directly and using anther ring disturbance as a proxy for lifetime visitation.Important Findings Floral phenotypes differed among species within communities in all functional traits.Visitor assemblages were diverse,including ants,beetles,flies,honeybees,moths and solitary bees.However,the Cape honeybee,Apis mellifera capensis,was the main pollinator of all but one Erica species.Insect visitation rates were significantly lower for E.imbricata and E.calycina relative to congeners,but high rates of anther ring disturbance,which differed significantly in only two out of seven comparisons,suggest that long-term visitation rates are mostly similar among species that share pollinators.This study shows that coexistence of co-flowering insect-pollinated Erica species is not determined by specialization for different pollination systems.Pollinator sharing might rather lead to facilitation among co-flowering species,and floral constancy mediated by extensive interspecific floral trait variation might mitigate its potentially nega-tive effects.