Malcolm T. Greenwood

Pond biodiversity and habitat loss in the UK

Ponds are common landscape features but have been poorly studied compared to other freshwater habitats in the UK, despite their high frequency of occurrence. In the last century, many ponds have been lost and those that remain face increasing pressure due to agricultural land drainage, pollution and urban development. However, ponds provide important habitats for diverse floral and faunal communities, including a number of rare taxa of conservation interest. This paper examines the biodiversity and wider environmental value of ponds, with particular reference to the aquatic invertebrate and amphibian communities they support, and the adverse impact of anthropogenic activity on their aquatic habitats.

The response of four lotic macroinvertebrate taxa to burial by sediments

Sedimentation is widely acknowledged as a major.cause of-degradation of instream habitats. However, macroinvertebrate burial by sediment has been poorly studied. Ex situ experiments were undertaken to examine the response of four common and abundant macroinvertebrate taxa (Baetis rhodani, Nemoura cambrica, Hydropsyche pellucidula, and Asellus aquaticus) to burial by six sediment size classes (range = 125 μm - 10mm in size) and two depths of burial (5 mm and 10mm). The nymphs of the ephemeropteran, Baetis rhodani, were unable to excavate themselves from any of the sediments. In contrast, the plecopteran nymphs of Nemoura cambrica were able to excavate themselves from all sediment classes and burial depths. Adults of the isopod, Asellus aquaticus, were able to excavate themselves rapidly from finer sediment classes ( 1 mm in size and became trapped in coarser sediments (>4 mm in size at 5 mm burial depth and > 2 mm at 10mm burial depth). The larvae of the trichopteran, Hydropsyche pellucidula, were able to excavate their heads from all sediment classes and both burial depths, but became trapped in particles <500 μm in size when buried under 10 mm of sediment. The results demonstrate that the response of individual taxa to burial with sediments is highly variable. Consequently, many of the documented changes to benthic macroinvertebrate community composition due to sedimentation probably mask a variety of individual faunal responses.

The effects of amenity management for angling on the conservation value of aquatic invertebrate communities in old industrial ponds

Abstract The conservation value of aquatic macroinvertebrate assemblages in old industrial mill ponds was examined within the urban environment. Of the 60 pond sites identified, 18 (31%) have been drained and/or redeveloped since 1985. Canonical correspondence analysis identified differences between the invertebrate communities of managed and unmanaged ponds. Community composition was strongly influenced by the percentage of vegetation cover and the presence of stocked fish for recreational angling. Managed/stocked ponds have communities dominated by burrowing Oligochaeta and Chironomidae. Unmanaged sites had higher macroinvertebrate diversity compared to managed/stocked ponds and were typified by larval Trichoptera, Coleoptera and Zygoptera. However, unmanaged and ‘derelict’ sites are at greater risk of drainage and redevelopment in the urban environment. The potential conflict between active management of old industrial mill ponds for recreational angling and the conservation of macroinvertebrate biodiversity is explored.

The louse Trinoton anserinum (Amblycera: Phthiraptera), an intermediate host of Sarconema eurycerca (Filarioidea: Nematoda), a heartworm of swans

Abstract. The role of the louse Trinoton anserinum (F) as an intermediate host of Sarconema eurycerca (Wehr) was investigated in swans. 8.3% of healthy swans carried one to twelve lice per bird, dispersed contagiously. Injured and lead‐poisoned swans were more heavily infected.

INSECT FOSSILS AND IRRIGATION IN MEDIEVAL GREENLAND

Abstract Initial uropean, orse, settlement in south‐west reenland lasted from the late tenth to the fifteenth century, with an economy largely based on secondary products from sheep, goats and cattle, supplemented by caribou and marine mammal hunting. Sustainable subsistence farming required acquisition of sufficient fodder, principally hay, to feed stalled animals through extended subarctic winters. At the cathedral site of arðar, the modern sheep farm of galiku, artefact scatters and geoarchaeological evidence show that infields were improved by manuring, and systems of ditches have been interpreted as evidence for controlled irrigation in an area liable to a potential water deficit. Further palaeoecological evidence, largely from insect remains, is presented which indicates the build up of thick plaggen soils as a result of large‐scale manuring with animal, domestic and structural waste, perhaps supplemented by pared turf. It is suggested that the technique of irrigated hayfields was utilized principally to provide fodder for the large numbers of cattle maintained on the bishops farm. The system appears to have been abandoned abruptly in the late medieval period, when wetland takes over from irrigated hayfield.

River Science: Research and Management for the 21st Century

This volume represents the outcome of research by many of the authors and their colleagues over the last 40 years and demonstrates the integral role that River Science now plays in underpinning our understanding of the functioning of natural ecosystems, and how societal demands and historic changes have affected these systems. The book will inform academics, policy makers and society in general of the benefits of healthy functioning riverine systems, and will increase awareness of the wide range of ecosystem goods and services they provide.

Automatic recording of flea activity

Abstract. An Insect Activity Monitor was created to measure the behavioural responses of fleas (Siphonaptera). The apparatus allows for a range of visual, chemo‐ and mechanoreceptor cues to be presented. The jumping response is detected by counting amplified pulses produced as the fleas land on a stretched membrane held over a microphone. Horizontal movements are detected using a system of infra‐red beams and phototransistors which, when broken, are counted as a measure of activity.

A circadian rhythm of locomotor activity in newly emerged Ceratophyllus sciurorum

Abstract Circadian rhythm in newly emerged individuals of the Red Squirrel (Scuirus vulgaris) flea C.s. sciurorum was studied in a constant environment, using an insect activity monitor. Trials were run over 7 days using two start times (08.00 and 17.00 hours). The results show that, regardless of start time, the fleas display a 24 h activity rhythm. The presence of a rhythm under constant conditions gives a strong indication that C. s.sciurorum has a self‐sustaining clock which is started by disturbance and is most likely to be linked to host activity patterns.