C. Philip Wheater

The implications of grassland and heathland management for the conservation of spider communities: a review

Both intensity and type of habitat management in grasslands and heathlands affect spider communities. With high intensity management, spider communities often lack diversity and are dominated by a few r -selected species affiliated with bare ground. Low intensity management produces more complex communities introducing more niches for aerial web spinners and climbing spiders. The preferred management will be site-dependent and may not be appropriate for all spiders in all situations, particularly for some rare or threatened species. Providing natural cover is recommended when using extreme forms of management or intensive grazing (particularly by sheep). In extreme cases, or where trampling is heavy, the litter layer should be conserved. We advocate research and survey before and after major management implementation. Habitat management for spiders should not be considered alone, but integrated into a holistic plan. Management for spiders may conflict with rare plant conservation and small reserves should examine the viability of providing two contrasting regimes.

Peer assessment of oral presentations: effects of student gender, university affiliation and participation in the development of assessment criteria

Peer assessment provides a useful mechanism to develop many positive qualities in students studying in higher education (HE). Potential influences on peer‐awarded marks include student qualities such as gender, HE background (e.g. university affiliation) and participation in the development of the assessment criteria. Many studies that have investigated peer assessment have placed great emphasis on marks from a single tutor, or very few tutors, from a single university. This study examined grades awarded by 11 tutors (affiliated with four universities) to oral presentations delivered on a residential field course by second‐year undergraduate students from two universities studying environmental or biological disciplines. Student assessors awarded marks of fairly high precision (correlating strongly with tutor grades) but averaged 5% higher than their tutors (i.e. of only moderate accuracy). Marginally higher marks (circa 1.6%) were awarded by student assessors to speakers studying at the same university. Gender influences were detected as males tended to grade other male speakers very slightly more highly than female speakers. Marks from females were unaffected by speaker gender. Students who participated in the development of the assessment criteria did not achieve higher grades for their presentations. However, when these ‘participants’ were assessing, they awarded lower marks than their peers (i.e. closer to, but not as low as, those awarded by tutors). Lower marks were also awarded during the middle of sessions, possibly resulting from factors associated with motivation and attention of speakers and markers. Overall, the potential biases in marking by naive assessors examined in this study may influence the validity of marks generated by peer assessment schemes, but the experience of this type of assessment had positive effects on those involved.

Relationships between student characteristics and self‐, peer and tutor evaluations of oral presentations

There are many influences on how assessors grade themselves and others. Oral presentations are useful for exploring such factors in peer, self‐ and tutor marked assessments, being rapidly completed and assessed, commonly used in HE and very difficult to anonymize. This opportunistic study examined the effects of gender and level of attainment on the triangulation of marks awarded to student presenters. Grades generated by peer assessment were associated more strongly with tutor‐awarded marks than those from self‐assessment. For self‐assessment there was a strong effect of gender (female students undervalued their performance compared with tutor grades). Peer assessment produced higher marks than from tutors, perhaps because of the close‐knit community developed during residential courses. For tutor marks, the greatest variability was at the lower end of the scale, whereas peer assessors were most variable when marking students who self‐evaluated or peer assessed highly. Students awarded a narrower range of marks to peers compared with tutors, but when self‐assessing used a larger range. Presentations by students who admitted to little sleep the night before received lower grades from both peers and tutors, but this was not reflected by self‐assessments, suggesting they were unaware of their poorer performances. Sessions with fewer talks (four rather than seven) reduced the ‘dip’ in marks previously observed in the middle of sessions. Findings are discussed in the context of bias in this mode of assessment.

Establishment of species-rich vegetation on reclaimed limestone quarry faces in Derbyshire, UK

Abstract Landform replication attempts to create species-rich calcareous grassland ecosystems on disused limestone quarry faces. This is important because: (i) similar semi-natural communities are often at risk from agriculture and other development; and (ii) although there are many abandoned quarries of nature conservation importance, modern extraction processes increase the time required for natural colonisation. Quarry faces were blasted selectively to produce several landforms, including scree slopes which were hydroseeded with an appropriate seed mix based on local daleside communities. The vegetation communities established after 2 years on three such areas are compared with those of a natural daleside and seven disused quarries (40–85 years since abandonment). It is encouraging for the restoration programme that the vegetation communities on the landform replications are more closely allied to the natural dalesides than to the disused quarries. However, rabbit grazing appears to influence the species composition of the landform replications and the development of cover. The implications for the management of these sites are discussed.

RESISTANCE OF SPIDERS TO CRETACEOUS–TERTIARY EXTINCTION EVENTS

Abstract Throughout Earth history a small number of global catastrophic events leading to biotic crises have caused mass extinctions. Here, using a technique that combines taxonomic and numerical data, we consider the effects of the Cenomanian—Turonian and Cretaceous—Tertiary mass extinctions on the terrestrial spider fauna in the light of new fossil data. We provide the first evidence that spiders suffered no decline at the family level during these mass extinction events. On the contrary, we show that they increased in relative numbers through the Cretaceous and beyond the Cretaceous—Tertiary extinction event.

Spider communities as tools in monitoring reclaimed limestone quarry landforms

Spider communities are sensitive to a wide range of environmental factors and are potential ecological indicators which may be effective in the assessment and monitoring of restored ecosystems. One restoration technique of disused limestone quarry faces, landform replication, attempts to create landforms and ecosystems similar to those found on natural dalesides. Vegetation surveys indicate that communities developing on landform replications are more closely allied to natural dalesides than are those of naturally recolonised disused quarries. Assessment of the spider communities of three landform replication sites, a natural limestone daleside and seven naturally recolonised disused limestone quarries, using DECORANA and TWINSPAN, produced differing patterns of sites than those observed through the assessment of the vegetation communities. DECORANA assessment based on vascular plant species composition highlights the similarities between daleside and reclaimed site communities. The sensitivity of spider communities to vegetation structure and extent of bare ground highlights differences between sites and provides evidence of important differences in vegetation community development particularly in relation to cover and structure. Implications for the assessment of reclamation and restoration techniques are discussed.

Re-emerging syphilis: a detrended correspondence analysis of the behaviour of HIV positive and negative gay men

BackgroundRecent syphilis outbreaks in the UK have raised serious concerns about the sexual health of the population. Moreover, syphilis appears more likely to facilitate HIV transmission than any other sexually transmitted infection (STI).MethodsThe sexual and other risk behaviour of a sample of HIV positive and negative gay men with and without syphilis was subjected to a detrended correspondence analysis (DCA).ResultsA DCA plot was used to illustrate similarity of individuals in terms of their behaviours, regardless of their infection status. The majority of those with syphilis (78%; 18/23) fell into a high-risk group with more partners, and use of anonymous sex venues and drugs during sex. However, 16% of uninfected controls (8/49) and 62% of HIV positive individuals without syphilis (8/13) also fell into this high-risk group.ConclusionsUsing a statistical technique that is novel for this type of investigation, we demonstrate behavioural overlaps between syphilis-infected individuals in an ongoing UK outbreak and uninfected HIV positive and negative controls. Given the high-risk behaviour of a significant proportion of uninfected individuals, ongoing transmission of syphilis and HIV in this population seems likely.

Students assessing student: case studies on peer assessment

Abstract Peer-assessment can be viewed in many ways: from a tool for reflection by students to a method of reducing staff marking loads. When deciding whether to use peer-assessment, several questions arise. Can naïve inexperienced markers evaluate their peers? What factors influence student assessors? Should you ‘pass on’ your marking to students? This article considers current issues about peer-assessment by discussing preliminary findings from two current projects currently being undertaken.

Does the Small White Butterfly (Pieris rapae L.) Aggregate Eggs on Plants with Greater Gas Exchange Activity

Few studies have investigated insect egg-laying preferences in relation to photosynthesis or transpiration of their host plants. It has been suggested that intravarietal preferences of the small white butterfly (Pieris rapae L.: Pieridae) include larger plants with characteristically higher transpiration rates. Interestingly this species, like many other Lepidoptera, may detect biogenic CO2 gradients associated with photosynthesis. We studied egg-laying preferences in working farm environments examining relationships among host choice, plant gas exchange activity, and plant size. Females discriminated between plants in monocultures on the basis of height. A balance of pre- and post–alighting preferences resulted in plants of medium size receiving eggs. Post–alighting preferences led to plants, but not alighted leaves, with higher rates of photosynthesis supporting eggs. These findings do not support a mechanistic basis for the use of gas exchange activity during host selection but, for the first time, indicate the greater physiological activity of crop plants that ultimately received the eggs of a pest insect.

Group work in the teaching of ecology

Recent experience of using small group work in teaching ecological subjects has identified factors for consideration when using these techniques. The advantages of group work are discussed from an academic perspective and several examples of its use in higher education are described. Experience has shown that there are many areas of concern relating to the planning, management, and implementation of group work. Several potential problems of such work are examined together with their associated solutions. Positive recommendations are made for the smoother operation and management of group work for undergraduate teaching and learning.