Margins of agricultural fields as habitats for pollinating insects

BiologicalConservation 1993, 65, 185-189

SELECTED ABSTRACTS The abslracts reproduced here have been selected from the coverage of Ecological

Abstracts. Further information on Ecological Abstracts, and the associated online database GEOBASE is available from Elsevier/Geo Absttacts, Regency House, 34 Duke Street, Norwich, UK, HR3 3AP.

NATURE CONSERVATION General 93Z/00001 Gap Analysis: a geographic approach to protection of biological diversity J.M. Scott & 11 others, Wildlife Monographs, 123, 1993, 41pp. Gap Analysis identifies the gaps in representation of biological diveristy in areas managed exclusively or primarily for the long-term maintenance of populations of native species and natural ecosystems (hereinafter referred to as biodiversity management areas). Once identified, gaps are filled through new reserve acquisitions or designations, or through changes in management practices. The goal is to ensure that all ecosystems and areas rich in species diveristy are represented adequately in biodiversity management areas. This proactive strategy eliminates the need to list many species as threatened or endangered in the future. -from Authors 93Z/00002 Allocating conservation expenditures: accounting for inter-species genetic distinctiveness M. E. Eiswerth & 3. C. Haney, Ecological Economics, 5(3), 1992, pp 235-249. During recent attempts to discuss biological diversity, economists have drawn upon the tools and techniques of mainstream resource economics to estimate the values of species. This can lead to a tendency to focus on the importance of species in isolation to one another and on the numbers of species (species richness) in natural areas. Such an approach does not incorporate the ongoing afforts of scientiststo define and analyze differenttypes of diversity among species and natural systems (eg genetic diversity and ecosystem diversity). The authors show how potential guidelines for the allocation of conservation expenditures among regions might be changed by consideration of the 'genetic distinctiveness' of species in addition to the numbers of species, inhabiting those regions. -from Authors 93Z/00003 Overview of remote sensing for range management P.T. Tueller, Geocarto International, 7(1), 1992, pp 5-10. Explores a possible approach to the management of a typical sagebrush/grass rangeland allotment. Consideration is given to use of aerial photography, digital image processing, video systems, vegetation indices, high resolution space and aircraft systems, geographic information systems and expert systems. -from Author 93Z/00004 Long-term monitoring of non-forest communities for biological conservation K. J. M. Dickinson, A. F. Mark & W. G. Lee, New Zealand Journal of Botany, 30(2), 1992, pp 163-179. A height-frequency method of vegetation sampling was adequate to describe both the structure and composition of a wide range of indigenous non-forest ecosystems. It is also useful in following both spatial and temporal changes

in such ecosystems, with comparisons being capable of statistical testing. -from Authors 93Z/00005 Spatial scale mediates the influence of habitat fragmentation on dispersal success: implications for conservation D . F . Doak, P. C. Marino & P. M. Kareiva, Theoretical Population Biology, 41(3), 1992, pp 315-336. A simple spatial model simulates the dispsersal of animals in a landscape of stochastically clustered habitat fragments. Varying the number of clusters and the spatial scale at which clustering occurs illustrates that heterogeneity has different and conflicting effects on animal movement when it occurs at different scales. Scale of clustering is the most important feature in determining disperser performance. Explicit consideration of scale is essential in discussions of habitat fragmentation and of optimal conservation strategies. -after Authors 93Z/00006 Agroecosystem biodiversity: matching production and conservation biology M.G. Paoletti, D. Pimentel, B. R. Stirmer & D. Stinner, Agriculture, Ecosystems & Environment, 40(1-4), 1992, pp 3 -23. Sustainable strategies in food production in agriculture improve existing biodiversity and include the following items: increased porosity of the landscape through proper management of natural vegetation, better use and recycling of organic residues, introduction of integrated farming systems, reduced tillage, rotation, biological control, increased number of biota involved in human food webs. -from Authors 93Z/00007 Field margins: can they enhance natural enemy population densities and general arthropod diversity on farmland?

P. Dennis & G. L. A. Fry, Agriculture, Ecosystems & Environment, 40(1-4), 1992, pp 95-115. The value of field margins to agriculture was assessed as the density of arthropods overwintering in these habitats. The arthropod groups used for the assessment were known aphid predators which moved out into cereal crops in the spring. This assessment was compared with general arthropod diversity at each site to test whether field margins supporting high densities of predators were also of value to nature conservation in supporting greater arthropod biodiversity. In spring, the spatial dynamics of predatory arthropod species were investigated in cereal crops adjacent to field-margin overwintering sites. Enhancement of natural enemies and general arthropod conservation are discussed as components of overall biological diversity at the farm scale. -from Authors 93Z/00008 Margins of agricultural fields as habitats for pollinating insects J. Lagerlof, J. Stark & B. Svensson, Agriculture, Ecosystems & Environment, 40(1-4), 1992, pp 117-124. Occurrence of pollinating insects in field margins with different vegetation was studied. Some margins were widened and vegetation was established by sowing leguminous plants or was allowed to invade spontaneously. Communities of pollinating insects in reclaimed field margins were

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Selected abstracts

compared with those of a margin with a naturally diverse flora and an adjacent pasture. Collection of pollen by honey-bees Apis mellifera was followed over the season in order to compare the bees' preferences with the supply of flowering plants available i n the different experimental field margins. The sown leguminousplants were very attractive to most insect groups, especially bees and bumble-bees, and their pollen constituted an ~.portant part of the bees' total catch. The vegetation established by spontaneous succession especially attracted Syrphidae and other groups of Diptera. Buttterflies were found-in all vegetation types. -from Authors 93Z/00009 Effects of headland management on invertebrate communities in cereal fields M. HassaU, A. Hawthorne, M. Maudsley, P. White & C, Cardwell, Agriculture, Ecosystems & Environment, 40(1-4), 1992, pp 155-178. Two of the management prescriptions for the Breckland Environmentally Sensitive Area in East Anglia, Great Britain, concern the outer 6m of cropped fields; 'Uncrop .ped Wildlife Strips' (no crop sown and restricted pesucide applications) and 'Conservation Headlands' (restricted estieide applications). Total abundance of each group was ighest in uncropped strips, but also higher in Conservation Headlands than in fully sprayed headlands. Species diversity for spiders and Heteroptera was significantly higher in uncropped strips and Conservation Headlands than in fully sprayed headlands. Species richness for both these groups and carabids was higher in all fields in uncropped headlands and Conservation Headlands than in the fully sprayed controls. The community structure of carabids and spiders was altered by headland management; it also changed with the age of the uncropped strips. Movement of Heteroptera from field boundaries into the crop was affected by headland trealment. -from Authors

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93Z/00010 Wasser: Biologie und Umweltqualitat (Water: biology and environmental quality) R. Kinzelbach, in: Wasser. Eine Einfuhring in die Umweltwissenschaflen, ed H.R. Bohm & M. Deneke, (Wissenschaftliche Buchgesellschaft, Darmstadt), 1992, pp 39-71. Human utilization and destruction of water is so extensive that renamring of water course is impracticable; protection and servicing are better than repair. Local specialist engineers and ecologists should be trained in greater numbers to initiate projects and protection work for early implementation. -R.Hardbottle

Species conservation 93Z/00011 Some comparative insect conservation issues of north temperate, tropical, and south temperate landscapes M . J . Samways, Agriculture, Ecosystems & Environment, 40(1-4), 1992, pp 137-154. The network of natural and artificial habitats, such as hedgerows, woodland rides and small tropical forest clearings, has often been beneficial for certain insect communities. In recent decades this situation has changed, and Europe has lost many of its remaining wetlands, heaths and ancient woods, while in the tropics habitat modification has been recent and sweeping. Both north and south temperate conservationists are actively engaged in insect conservatinn efforts, but in the tropics, where the insect fauna is the richest and most imperilled, it is, in general, least cared for. With the inevitable increasing pressure and need for reconciliation between agriculture, urbanization and conservation, insects feature strongly as subjects for concem. After consideration of latitudinal differences in temperatures, the biology and conservation requirements of tropical insects are not verst different from those of temperate species. Intact habltats are the key. But where landscape modification is inevitable, landscape features such as hedgerows, saums and mantels can be incorporated into ecological landscaping to go some way to preserving the diverse tapestry of insect life in the tropics. -from Authors

93Z/00012 Strategy for conservation of wild bees in an agricultural landscape J. Banaszak, Agriculture, Ecosystems & Environment, 40(I-4), 1992, pp 179-192. Investigations carried out for 15 yr on the WielkopolskoKujawska Lowland (W Poland) showed that wild bees (Apoidea) are under strong human pressure. About 260 bee species were found in the area of 20 000km 2. In a normally functioning agricultural landscape, the share of farmland should not exceed three-quarters of the total surface. The remaining part of the landscape should be made up of refuge habitats for Apoidea. -from Author

93Z/00013 The nesting success of green turtles on beaches at Kazanli, T u r k e y S.J. Coiey & A. C. Smart, Oryx, 26(3), 1992,pp 165-171. The three main nesting beaches of Chelonia mydas in Turkey are in the east, with possibly the densest congregation of nesting turtles in the Mediterranean being found at KazanlL Beach erosion, hatchling predation, agricultural encroachment and chemical pollution mean that the future of the Kazanli nest site is uncertain. The Turkish Society for the Protection of Nature is making efforts to protect all the turtle nesting beaches in Turkey but lacks detailed information on turtle numbers. This paper describes a short study of nesting turtles at Kazanli during 1990 and makes recommendations for the conservation of the nesting beach. -from Authors

93Z/00014 Boabeng-Fiema Monkey S a n c t u a r y - an example of traditional conservation in G h a n a P. J~ Fargey, Oryx, 26(3), 1992, pp 151-156. Villagers who live in the Boabeng-Fiema Monkey Sanctuary have traditionally had a taboo against killing the blackand-white coinbus Colobus polykomos and mona monkey Cercopithecus campbelli which inhabit the forest around their vill.a~es. The sanctuary is an impox~mt example of how traditional values in Ghana have resulted in wildlife conservation. The monkeys are not immediately threatened but some of the forest that the monkeys rely on has become degraded or destroyed. -from Author

93Z/00015 A glut of gibbons in S a r a w a k - is rehabilitation the answer? J. Bennett, Oryx, 26(3), 1992, pp 157-164. Bomean gibbons Hylobates muelleri are protected by law in Sarawak, but their habitat is being destroyed, they are illegally hunted and they are captured for the pet trade. The Wildlife Rehabilitation centre at Semengok Forest Reserve receives confiscated gibbons and those surrendered by the general public. Between October 1976 and June 1988, 122 gibbons were received and 87 were subsequently released. Survey of the forest at Semengok in 1988 revealed that c90% of the gibbons d i d not survive long after release. The author discusses the reasons for this high mortality rate, the shortcomings of rehabilitation as a conservation tool, the problems facing the conservation authorities, and options for dealing with confiscated primates. -from Author

93Z/00016 The decline of the K a l a h a r i wildebeest C . A . Spinage, Oryx, 26(3), 1992, pp 147-150. In the 1980s international publicity was given to the deaths of thousands of Connochaetes tuurinus in southern Botswana. The cause was their drought-induced migrations being prevented by the cordon fences erected to protect cattle from disease. While the mortalities may have accounted for 90% of the wildebeest pouplation since 1979, archive records from the 1920s a n d 1940s show that the decline started much earlier. Wildebeest were once so numerous in the S Kalahari that local farmers ~.garded them as a menace, competing with cattle for grazmg and transmitting malignant catarrh. Extermination programmes reduced the wildebeest population to such an extent that by