Controls on the 87Sr/86Sr ratios of carbonates in the Garhwal Himalaya, Headwaters of the Ganges

The episodic variation of the seawater 87Sr/86Sr ratio has been attributed to either variations in the Sr flux or the Sr-isotopic composition of the riverine-dissolved load derived from weathering of the continental crust. The discovery that Himalayan rivers are characterized by high concentrations of dissolved Sr concentrations with high 87Sr/86Sr ratios has raised the possibility that collisional orogens play a critical role in moderating the variations in seawater 87Sr/86Sr ratios. Here we describe Himalayan carbonates and calc-silicates from Garhwal, the headwaters of the Ganges, with extreme 87Sr/86Sr ratios (>1.0). Elevated Sr-isotope ratios result from exchange with Rb-rich silicate material during both Himalayan and pre-Himalayan metamorphic episodes, and the carbonates contribute a significant fraction to the Ganges 87Sr flux. Particularly elevated 87Sr/86Sr ratios are found in calc-silicates from the Deoban Formation of the Lesser Himalaya. A detailed traverse of shales and calc-silicates from this unit confirms that carbonate horizons have increased 87Sr/86Sr ratios as a result of isotopic exchange over length scales of 1030 cm. We conclude that metamorphism of carbonates may cause elevation of their 87Sr/86Sr ratios and that uplift of metamorphosed carbonates may be a consequence of collisional orogens, which contributes to the elevation of seawater 87Sr/86Sr ratios

Kom el-Farahy: a New Kingdom island in an evolving Edfu floodplain

Two seasons of geoarchaeological and geophysical fieldwork (2008, 2009) were conducted at a small mound, known locally as Kom el-Farahy, some 800m to the south-east of the necropolis of Hagr Edfu. The work shows that the site formed as an island in the Nile, suggesting that the river lay 3km to the west of Edfu town and temple during the New Kingdom. Geophysical fieldwork on the west side of the Edfu mound has clearly revealed the profile of the sandstone outcrop upon which the temple stands

Stratigraphic landscape analysis: charting the Holocene movements of the Nile at Karnak through ancient Egyptian time

Geological analysis of 5-10-m-long sediment cores in the context of the anthropologically derived materials within them has allowed us to identify ancient landscape features in the Theban area around Luxor, Egypt. From these observations we propose a sequence of island formation and northwestward movement of the Nile from the Middle Kingdom onward in the area of the temple complexes of Karnak. The geoarchaeological techniques used appear to document the Holocene lateral migration and vertical aggradation of the Nile. Our method can be used to test postulated movements and is applicable to sites in river or coastal plains where sediments were being deposited during the occupation of the site. The sediments were sieved to retrieve sherds and numerous other small items (2 mm and larger), which included worked stone fragments, rootlet concretions (rhizocretions), desert polished sand grains, and occasionally beads. The small stone fragments can be correlated with buildings and sherds of known age within the site, while the rhizocretions and desert sand grains indicate environmental conditions prevailing at the time of deposition

Native and alien flower visitors differ in partner fidelity and network integration

<div><div>These data files support the following publication</div><div><br></div><div>Trøjelsgaard, K., Heleno, R., & Traveset, A. <b>Native and alien flower visitors differ in partner fidelity and network integration</b>. Ecology Letters, <i>accepted. </i>doi: 10.1111/ele.13287</div><div><i><br></i></div><div>For more details see the Read Me file or the original publication.</div></div><div><br></div><div><b><u>Abstract</u></b></div><div>Globalisation persistently fuels the establishment of non-native species outside their natural ranges. While alien plants have been intensively studied little is known about alien flower visitors, and especially, how they integrate into natural communities. Here we focus on mutualistic networks from five Galápagos islands to quantify whether alien and native flower visitors differ consistently in their pairwise interactions. We find that i) alien flower visitors have more interaction partners and larger species strengths (i.e. plants are more connected to alien insects), ii) native insects tend to have higher partner fidelity as they deviate more from random partner utilization, and iii) the difference between native and alien flower visitors in network integration intensifies with island degradation. Thus, native and alien flower visitors are not interchangeable, and alien establishment might have yet unforeseen consequences for the pairwise dynamics between plants and flower visitors on the Galápagos – especially on the heavily disturbed islands. <br></div

A roadmap for island biology: 50 fundamental questions after 50 years of The Theory of Island Biogeography

Aims: The 50th anniversary of the publication of the seminal book, The Theory of Island Biogeography, by Robert H. MacArthur and Edward O. Wilson, is a timely moment to review and identify key research foci that could advance island biology. Here, we take a collaborative horizon-scanning approach to identify 50 fundamental questions for the continued development of the field. Location: Worldwide. Methods: We adapted a well-established methodology of horizon scanning to identify priority research questions in island biology, and initiated it during the Island Biology 2016 conference held in the Azores. A multidisciplinary working group prepared an initial pool of 187 questions. A series of online surveys was then used to refine a list of the 50 top priority questions. The final shortlist was restricted to questions with a broad conceptual scope, and which should be answerable through achievable research approaches. Results: Questions were structured around four broad and partially overlapping island topics, including: (Macro)Ecology and Biogeography, (Macro)Evolution, Community Ecology, and Conservation and Management. These topics were then subdivided according to the following subject areas: global diversity patterns (five questions in total); island ontogeny and past climate change (4); island rules and syndromes (3); island biogeography theory (4); immigration–speciation–extinction dynamics (5); speciation and diversification (4); dispersal and colonization (3); community assembly (6); biotic interactions (2); global change (5); conservation and management policies (5); and invasive alien species (4). Main conclusions: Collectively, this cross-disciplinary set of topics covering the 50 fundamental questions has the potential to stimulate and guide future research in island biology. By covering fields ranging from biogeography, community ecology and evolution to global change, this horizon scan may help to foster the formation of interdisciplinary research networks, enhancing joint efforts to better understand the past, present and future of island biotas. © 2017 John Wiley &amp; Sons Lt