A new Middle Pleistocene interglacial occurrence from Ejby, Sjælland, Denmark

Despite more than a century of investigations, parts of the Quaternary stratigraphy of Denmark with their fragmented record of deposits remain ambiguous. Here we describe a newly found interglacial clay deposit from Ejby on Sjælland, Denmark, from a borehole at 55.695°N, 11.839°E (terrain elevation 5.7 m above sea level). We place the new occurrence on record and provide details of the macrofossil analysis of the sample. The clay contains remains of the present-day temperate bivalve Corbicula fluminalis and the caddis fly Hydropsyche contubernalis – both inhabiting rivers. The presence of C. fluminalis indicates that the deposit most probably is of Middle Pleistocene age, older than the last interglacial, the Eemian

An Early Pleistocene interglacial deposit at Pingorsuit, North-West Greenland

At the Pingorsuit Glacier in North-West Greenland, an organic-rich deposit that had recently emerged from the retreating icecap was discovered at an elevation of 480 m above sea level.This paper reports on macrofossil analyses of a coarse detritus gyttja and peaty soil, which occurred beneath a thin cover of till and glacifluvial deposits. The sediments contained remains of vascular plants, mosses, beetles, caddisflies, midges, bryozoans, sponges and other invertebrates. The flora includes black spruce, tree birch, boreal shrubs and wetland and aquatic taxa, which shows that mires,lakes and ponds were present in the area.We describe an ewextinct water wort species Elatineodgaardii.The fossils were deposited in a boreal environment with a mean July air temperature that was at least 9°C higher than at present. The fossil assemblages show strong similarities with others from Greenland that have been assigned an Early Pleistocene age, and we suggest a similar age for the sediments found at the margin of the Pingorsuit Glacier. At the Pingorsuit Glacier in North-West Greenland, an organic-rich deposit was discovered at an elevation of 480 m above sea level. The sediments contained remains of vascular plants, mosses, beetles, caddisflies, midges, bryozoans,sponges and other invertebrates. The fossils were deposited in aboreal environment with a mean July air temperature that was at least 9°C higher than at present

Structural and functional responses of macroinvertebrate assemblages to long‐term flow variability at perennial and nonperennial sites

Temporary streams constitute a significant proportion of rivers globally and are common in wet, cool, temperate regions. These heterogeneous ecosystems harbour high biodiversity associated with the dynamic turnover of taxa. Despite flow permanence being widely recognised as an important environmental control, few studies have characterised biotic responses to long‐term hydrological variability in temporary streams. We examined taxonomic and functional macroinvertebrate communities of perennial and nonperennial river reaches over a 26‐year period. Flow permanence resulted in spatial variation in taxonomic and functional macroinvertebrate communities. Nonperennial river reaches, which were characterised by dynamic habitat provision (lotic, lentic, and dry states) over the study period, supported more heterogeneous communities than perennial river reaches. Hydrological variables, in particular wetted width, water depth, and zero‐flow states, were instrumental in structuring taxonomic and functional communities, although the importance of substrate conditions increased in autumn. Hydrological conditions resulted in separation of perennial and nonperennial taxonomic communities regardless of season, whereas functional communities differed only in spring. Our results emphasise that understanding of community responses to hydrological variability is enhanced by analyses that concurrently explore taxonomic and functional responses to long‐term intraannual and interannual hydrological variability. Moreover, functional responses represent a robust method to test ecological responses to hydrological drivers. Further research that builds on our work is needed to inform the protection of both perennial and nonperennial streams as they adapt to ongoing environmental change