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Arid regions are especially vulnerable to climate change and land use. More than one-third of Earth's population relies on these ecosystems. Modern observations lack the temporal depth to determine vegetation responses to climate and human activity, but paleoecological and archaeological records can be used to investigate these relationships. Decreasing rainfall across the Late Holocene provides a case study for vegetation response to changing hydroclimate. Rock hyrax (Procavia capensis) middens preserve paleoenvironmental indicators in arid environments where traditional archives are unavailable. Pollen from modern middens collected in Dhofar, Oman, demonstrates the reliability of this archive. Pollen, stable isotope (δ13C, δ15N), and microcharcoal data from fossil middens reveal changes in vegetation, relative moisture, and fire from 4000 cal yr BP to the present. Trees limited to moister areas (e.g., Terminalia) today existed farther inland at ~3100 cal yr BP. After ~2900 cal yr BP, taxa with more xeric affiliations (e.g., Senegalia) had increased. Coprophilous fungal spores (Sporormiella) and grazing indicator pollen revealed an amplified signal of domesticate grazing at ~1000 cal yr BP. This indicates that trees associated with semiarid environments were maintained in the interior desert during ~3000-4000 yr of decreasing rainfall and that impacts of human activity intensified after the transition to a drier environment. [ABSTRACT FROM AUTHOR]

Dionysia mira (Jaub. & Spach.) Wendelbo is endemic to the northern mountains of Oman, where it is restricted to a few isolated populations in the eastern and western Hajar Mountains; the extent of populations has not been accurately documented. Here we investigate the population size and distribution, habitat preferences, reproductive biology and potential threats, and ex‐situ conservation initiatives at Oman Botanic Garden are discussed. In 2017, 4045 flowering plants were recorded; of which 3595 were concentrated around the village of Shnoot on Jabal Al Akhdar in the western Hajar mountains. Plants are found between 1700 m and 2500 m a.s.l. on north facing limestone gravel slopes and fissures on vertical outcrops and cliff faces within Sideroxylon mascatense – Olea europaea and Teucrium mascatense – Juniperus seravschanica vegetation communities. Plant density within the core population at Shnoot is 52 plants/100 m2; 46% of which were mature plants, 32% semi‐mature and 15% seedlings. The mean number of seeds per plant was 14 000; bee‐flies (Bombyliidae) are suggested as likely pollinators. Using freshly collected seeds under controlled conditions between 10°C and 30°C a 90% germination rate was recorded; there was no difference in the germination rates between stratified and non‐stratified seeds. Dionysia mira is under threat from predicted climate change scenarios in the region and habitat loss through widespread development within its core range. Long‐term ex‐situ conservation programme at Oman Botanic Garden maintains a seed and living plant collection. [ABSTRACT FROM AUTHOR]