Nile waterscapes facilitated the construction of the Giza pyramids during the 3rd millennium BCE.

The pyramids of Giza originally overlooked a now defunct arm of the Nile. This fluvial channel, the Khufu branch, enabled navigation to the Pyramid Harbor complex but its precise environmental history is unclear. To fill this knowledge gap, we use pollen-derived vegetation patterns to reconstruct 8,000 y of fluvial variations on the Giza floodplain. After a high-stand level concomitant with the African Humid Period, our results show that Giza's waterscapes responded to a gradual insolation-driven aridification of East Africa, with the lowest Nile levels recorded at the end of the Dynastic Period. The Khufu branch remained at a high-water level (∼40% of its Holocene maximum) during the reigns of Khufu, Khafre, and Menkaure, facilitating the transportation of construction materials to the Giza Pyramid Complex.

Climate change: A driver of future conflicts in the Persian Gulf Region?

Ongoing global change and its direct environmental impacts, in addition to securing economic transition to the post-oil era, could trigger complex socio-economic and political crises in oil-dependent economies of the Persian Gulf Region (PGR). To evaluate the role of climate change and related policies in degrading the environment and its socio-economic impacts in the PGR, we have used a variety of available global datasets and published data. The results show that the countries of the PGR pursue some types of socio-economic reforms to alleviate the impacts of climate change. However, it seems that these attempts are not compatible with the environment's capacity. The main problem stems from the fact that political differences between the PGR nations prevent them from managing the Persian Gulf environment as an integrated natural system and consequently they have to limit their efforts within their borders, regardless of what happens in other parts of the system. The shift to alternative revenue sources by the countries needs socioeconomic preparedness while there are environmental obstacles, political tensions and geopolitical rivalries. Unless there is a cooperative approach to mitigate the effects of climate change, accompanied by a reorientation of PGR economies, the situation is likely to worsen rather than improve. To address the challenges of climate change, integrated regional collaborations are needed. Collective action, such as more investment in regional research and development and education, is required if the PGR is to successfully transition from a commodity-based to a knowledge-based economy.

A Review of C4 Plants in Southwest Asia: An Ecological, Geographical and Taxonomical Analysis of a Region With High Diversity of C4 Eudicots.

Southwest Asia is climatically and topographically a highly diverse region in the xeric belt of the Old World. Its diversity of arid habitats and climatic conditions acted as an important area for the evolution and diversification of up to 20 (of 38 known) independent Eudicot C4 origins. Some of these lineages present unique evolutionary strategies like single-cell functioning C4 and C3-C4 switching mechanisms. The high diversity of C4 taxa in Southwest (SW) Asia is also related to the presence of seven phytogeographic zones including the Irano-Turanian region as a center of diversification of many Caryophyllales lineages and the Somali-Masai region (Southern Oman and Yemen) as a center of diversification for C4 Monocots. Nevertheless, the C4 flora of SW Asia has not received detailed attention. This paper presents a comprehensive review of all known C4 species in the area based on a literature survey, own floristic observations, as well as taxonomic, phylogenetic and herbarium data, and δ13C-isotope ratio analysis. The resulting checklist includes a total number of 923 (861 native, of which 141 endemic, and 62 introduced) C4 species, composed of 350 Eudicots and 509 Monocots, most of which are therophytic and hemicryptophytic xerophytes with pluriregional and Irano-Turanian distribution. Two hundred thirty-nine new δ13C-isotope ratios of C4 and C3 plants, as well as some taxonomic changes are presented. An analysis of the distribution of the three main C4 plant families (Chenopodiaceae, Poaceae, and Cyperaceae) in the region in relation to climatic variables indicates that the increase of C4 species follows more or less a latitudinal gradient similar to global patterns, while separate taxonomic groups seem to depend on specific factors as continentality (Chenopodiaceae), average annual temperature (Cyperaceae), and the presence of summer precipitation (Poaceae). An increase of C4 Eudicots in W-E direction even in similar longitudinal belts is explained by a combination of edaphic and climatic conditions. The provided data should encourage a deeper interest in the evolution of C4 lineages in SW Asia and their adaptation to ecological and climatical conditions and awaken interest in the importance of local C4 crops, the conservation of threatened C4 taxa, and awareness of human impacts on the rapid environmental changes in the region.

20,000 years of societal vulnerability and adaptation to climate change in southwest Asia.

The Fertile Crescent, its hilly flanks and surrounding drylands has been a critical region for studying how climate has influenced societal change, and this review focuses on the region over the last 20,000 years. The complex social, economic, and environmental landscapes in the region today are not new phenomena and understanding their interactions requires a nuanced, multidisciplinary understanding of the past. This review builds on a history of collaboration between the social and natural palaeoscience disciplines. We provide a multidisciplinary, multiscalar perspective on the relevance of past climate, environmental, and archaeological research in assessing present day vulnerabilities and risks for the populations of southwest Asia. We discuss the complexity of palaeoclimatic data interpretation, particularly in relation to hydrology, and provide an overview of key time periods of palaeoclimatic interest. We discuss the critical role that vegetation plays in the human-climate-environment nexus and discuss the implications of the available palaeoclimate and archaeological data, and their interpretation, for palaeonarratives of the region, both climatically and socially. We also provide an overview of how modelling can improve our understanding of past climate impacts and associated change in risk to societies. We conclude by looking to future work, and identify themes of "scale" and "seasonality" as still requiring further focus. We suggest that by appreciating a given locale's place in the regional hydroscape, be it an archaeological site or palaeoenvironmental archive, more robust links to climate can be made where appropriate and interpretations drawn will demand the resolution of factors acting across multiple scales. This article is categorized under:Human Water > Water as Imagined and RepresentedScience of Water > Water and Environmental ChangeWater and Life > Nature of Freshwater Ecosystems.

Past and future global transformation of terrestrial ecosystems under climate change.

Impacts of global climate change on terrestrial ecosystems are imperfectly constrained by ecosystem models and direct observations. Pervasive ecosystem transformations occurred in response to warming and associated climatic changes during the last glacial-to-interglacial transition, which was comparable in magnitude to warming projected for the next century under high-emission scenarios. We reviewed 594 published paleoecological records to examine compositional and structural changes in terrestrial vegetation since the last glacial period and to project the magnitudes of ecosystem transformations under alternative future emission scenarios. Our results indicate that terrestrial ecosystems are highly sensitive to temperature change and suggest that, without major reductions in greenhouse gas emissions to the atmosphere, terrestrial ecosystems worldwide are at risk of major transformation, with accompanying disruption of ecosystem services and impacts on biodiversity.

A note on the biogeographical origin of the brine shrimp Artemia urmiana Günther, 1899 from Urmia Lake, Iran.

The brine shrimp Artemia urmiana, an abundant inhabitant of the hypersaline Urmia Lake in northwestern Iran, has recently been described from Lake Koyashskoe, also a shallow hypersaline lake that is located on the Black Sea coast of the Crimean Peninsula (Ukraine). This discovery has questioned the endemicity of A. urmiana in Urmia Lake and has also brought into question the biogeographical origin of this species. In the present study, we combined recent genetic divergence data (mtDNA-COI) with palaeoecological evidence to address the biogeographical origin of A. urmiana. Calibration of the molecular clock of the COI region was set by assigning the age of the micro-crustacean Daphnia pulex minimally at 145 Mya. The divergence age of A. urmiana in Urmia Lake dates back to 383,000 years, whereas Ukrainian Artemia reflects a very young populations that diverged about 196,000 years ago. Palaeoecological evidence suggests that the age of the major habitat of A. urmiana i.e. Urmia Lake goes back to the Tertiary Period while the Ukranian habitats of the species are very young, by virtue of geological features of the Holocene age. We conclude that the biogeographical origin of A. urmiana is outside of Europe and the current state of knowledge strongly suggests that Urmia Lake has been the major source of its expansion into its modern habitats in Europe.

[Pollen analysis from two littoral marshes (Bourdim and Garaat El-Ouez) in the El-Kala wet complex (North-East Algeria). Lateglacial and Holocene history of Algerian vegetation]. / Nouvelles contributions à l'histoire tardiglaciaire et holocène de la végétation en Algérie: analyses polliniques de deux profils sédimentaires du complexe humide d'El-Kala.

The study of two pollen sequences from El-Kala marshes allowed the reconstruction of the regional vegetation history supported by eight radiocarbon dates. Pollen assemblages from Bourdim site were dominated by local input of Alnus and Salix, while regional vegetation was characterized by scattered Quercus suber forests with a well-developed Erica arborea matorral. While the vegetation dynamics recorded at Bourdim is recent (Late Holocene), the majority of the pollen diagram from Garaat El-Ouez is contemporaneous to the Late Pleniglacial and is characterized by open woodlands with Pinus, Poaceae and several heliophilous herbs. The significant values of Cedrus pollen identified in this period indicate that the region of El-Kala most probably played the role of a refugium for this tree.