Two members of the pgip gene family (pgip-1 and pgip-2) of Phaseolus vulgaris L. were expressed separately in Nicotiana benthamiana and the ligand specificity of their products was analysed by surface plasmon resonance (SPR). Polygalacturonase-inhibiting protein-1 (PGIP-1) was unable to interact with PG from Fusarium moniliforme and interacted with PG from Aspergillus niger; PGIP-2 interacted with both PGs. Only eight amino acid variations distinguish the two proteins: five of them are confined within the β-sheet/β-turn structure and two of them are contiguous to this region. By site-directed mutagenesis, each of the variant amino acids of PGIP-2 was replaced with the corresponding amino acid of PGIP-1, in a loss-of-function approach. The mutated PGIP-2s were expressed individually in N.benthamiana, purified and subjected to SPR analysis. Each single mutation caused a decrease in affinity for PG from F.moniliforme; residue Q253 made a major contribution, and its replacement with a lysine led to a dramatic reduction in the binding energy of the complex. Conversely, in a gain-of-function approach, amino acid K253 of PGIP-1 was mutated into the corresponding amino acid of PGIP-2, a glutamine. With this single mutation, PGIP-1 acquired the ability to interact with F.moniliforme PG.

A central issue in ecology lies in identifying the importance of resources, natural enemies and behaviour in the regulation of animal populations. Much of the debate on this subject has focused on animals that show cyclic fluctuations in abundance. However, there is still disagreement about the role of extrinsic (food, parasites or predators) and intrinsic (behaviour) factors in causing cycles. Recent studies have examined the impact of natural enemies, although spatial patterns resulting from restricted dispersal or recruitment are increasingly recognized as having the potential to influence unstable population dynamics. We tested the hypothesis that population cycles in a territorial bird, red grouse Lagopus lagopus scoticus, are caused by delayed density-dependent changes in the aggressiveness and spacing behaviour of males. Here we show that increasing aggressiveness experimentally for a short period in autumn reduced recruitment and subsequent breeding density by 50%, and changed population trajectories from increasing to declining. Intrinsic processes can therefore have fundamental effects on population dynamics.

The successful resolution of human-wildlife conflicts requires the participation of local communities and other stakeholder groups in formulating management decisions. In the uplands of the United Kingdom, a controversial conservation issue concerns the relationship between the conservation of a legally protected raptor, the Hen Harrier (Circus cyaneus) and the management of a gamebird, the Red Grouse (Lagopus lagopus scoticus). We used multicriteria analysis to evaluate the perspectives of two groups of stakeholders, grouse managers and raptor conservationists, and the acceptability to them of different management solutions to this conflict. Both groups quantified the relative importance of evaluation criteria and used these as a basis for comparing different upland and Hen Harrier management options. In relation to upland management, grouse managers placed more importance on economic criteria than did raptor conservationists, who valued natural-environment criteria more highly. Intensively managed grouse moors, involving the control of harrier numbers, were ranked most highly by grouse managers and managed nature reserves by raptor conservationists, but both groups also ranked legally managed grouse moors highly. When evaluating Hen Harrier management options, grouse managers considered time scale and cost the most important criteria, whereas raptor conservationists considered the effects on harrier populations to be most important. Harrier quota schemes were the management solution most favored by grouse managers, whereas raptor conservationists preferred allowing harriers to attain natural densities. Notably, however, one technique that has already been partly tested in the field-the use of diversionary feeding was scored highly by both groups and thus holds promise for some form of compromise. This exercise highlighted the value of these objective techniques for developing dialog and trust between stakeholder groups, and it highlighted the need to conduct further research to test the effectiveness of different management options. There was broad agreement that the workshop moved the prior positions of individual stakeholders and was a valuable tool in helping to resolve human-wildlife conflicts.Utilización de Modelos de Decisión con Grupos de Interés para Reducir Conflictos Humanos-Vida Silvestre: un Estudio de Caso Rapaz-Codorniz Resumen: La solución exitosa de conflictos humanos-vida silvestre exige la participación de comunidades locales y otros grupos de interés para la formulación de decisiones de manejo. Un tema controvertido de conservación en las tierras altas del Reino Unido se refiere a la relación entre la conservación de una rapaz legalmente protegida (Circus cyaneus) y el manejo de una ave de presa cinegética ( Lagopus lagopus scoticus). Utilizamos análisis de criterios múltiples para evaluar las perspectivas de dos grupos de interés (manejadores de Lagopus lagopus scoticus y conservacionistas de rapaces) y su aceptabilidad de diferentes soluciones de manejo de este conflicto. Ambos grupos cuant...

Summary 1.Hen harriers Circus cyaneus can reduce the numbers of red grouse Lagopus lagopus scoticus available for shooting. We conducted a supplementary feeding experiment on Langholm Moor, UK, in 1998 and 1999 to determine whether feeding hen harriers could reduce the numbers of red grouse killed. The experiment was done at two distinct stages of the breeding cycle: prior to incubation (spring experiment) and after hatching (summer experiment). In spring, Langholm Moor was divided into two areas, one with food and one without. In summer a number of birds were provided with food in both areas. 2. Providing harriers with food in spring had no significant effect on the breeding density of males or females, although feeding was associated with an increase in density on one area in one year. In addition, over the 2 years of the experiment, there was no evidence that feeding led to more chicks returning to breed in subsequent years. Fed harriers had larger clutches but did not lay earlier than unfed birds. 3. A minimum of 78% of the radio-tagged grouse that were killed during spring were killed by raptors. The mortality rates of adult grouse did not differ between the two areas or between the two years despite the availability of supplementary food and the large differences in harrier breeding density between areas. We infer that other raptors were responsible for much of the predation of adult grouse. 4. During the nestling period, female harriers took supplementary food at a higher rate than males. Females that were fed during the spring took more supplementary food in summer than those fed only during summer. Fed birds did not deliver more food overall to nests than those not provided with food. 5. Both male and female harriers at nests where supplementary food was available caught grouse chicks at a lower rate than harriers at nests not provided with food. For both years combined, fed harriers delivered on average 0·5 grouse chicks to their nests per 100 h, compared with 3·7 grouse chicks delivered to nests without supplementary food. 6. We estimated that feeding all harriers at Langholm would cost approximately £11 000 per annum. In both 1998 and 1999, the numbers of grouse chicks lost were 10 times higher than expected from harrier predation rates. Some other, unknown, factor had a strong influence on grouse chick survival in these years. Feeding some of the breeding harriers did not lead to an increase in grouse density at Langholm. 7. The results suggest that supplementary feeding may provide a useful tool in reducing the number of grouse chicks taken by harriers. Further experiments are now necessary to see under what conditions this reduced predation will lead to increases in grouse density.

The role of parasites in regulating populations has been the subject of debate. We tested whether parasites caused population cycles in red grouse by manipulating parasite intensities in four, paired 1 km(2) study areas during cyclic population declines over 4 years. Parasite reductions led to (1) larger grouse broods, (2) higher population densities in both autumn and spring, (3) reduced autumn population declines in one of two regions, and (4) reduced spring declines, but only in the first year. We infer that a single trophic interaction between a parasite and its host does not explain cyclic dynamics in spring breeding density in this species, although it contributed to the start of a cyclic decline. Another process was operating to drive the populations down. Together with our other results these findings emphasize that both trophic and intrinsic processes may act within populations to cause unstable dynamics.