Consequences of the size structure of fish populations for their effects on a generalist avian predator

Size-structured interspecific interactions can shift between predation and competition, depending on ontogenetic changes in size relationships. I examined the effects of common carp (Cyprinus carpio), an omnivorous fish, on the reproductive success of the red-necked grebe (Podiceps grisegena), an avian gape-limited predator, along a fish size gradient created by stocking distinct age-cohorts in seminatural ponds. Young-of-the-year (0+) carp were an essential food source for young grebes. Only adult birds were able to consume 1-year-old (1+) fish, while 2-year-old (2+) fish attained a size refuge from grebes. Amphibian larvae were the principal alternative prey to fish, followed by macroinvertebrates, but the abundance of both dramatically decreased along the carp size gradient. Fledging success was 2.8 times greater in ponds with 0+ versus 1+ carp; in ponds with 1+ carp, chicks received on average 2.6–3 times less prey biomass from their parents, and over 1/3 of broods suffered total failure. Breeding birds avoided settling on 2+ ponds. These results show that changes in prey fish size structure can account for shifts from positive trophic effects on the avian predator to a negative impact on the predator’s alternative resources. However, competition did not fully explain the decrease in grebe food resources in the presence of large fish, as carp and grebes overlapped little in diet. In experimental cages, 1+ carp totally eliminated young larvae of amphibians palatable to fish. In field conditions, breeding adults of palatable taxa avoided ponds with 1+ and older carp. Non-trophic interactions such as habitat selection by amphibians or macroinvertebrates to avoid large fish may provide an indirect mechanism strengthening the adverse bottom-up effects of fish on birds

Ringing recoveries and the increase in numbers of European great crested grebes **Podiceps cristatus**

This study investigated the mentoring functions and the supervisory relationships of 20 preservice and cooperating teacher-dyads in student teaching. Utilizing three instruments, Mentoring Functions, Supervisory Relationship Measure (SRM), and Supervisory Relationship Questionnaire (SRQ), the compatibility of their mentoring perceptions, their level of satisfaction within their supervisory relationship, and the possible relatedness between the two were examined. The analyses of the results indicated that the mentoring perceptions of the dyads were highly compatible/congruent, with the highest degree of compatibility in the subscales of Advocacy and Role Modeling. Also, the dyads indicated that Coaching, Role Modeling, and Learning Facilitation were the three most important factors in mentoring. Additionally, it was determined that both groups had high degree of satisfaction in their supervisory relationship, more so for the cooperating teachers than for the preservice teachers. Finally, Mentoring Functions (mentoring perceptions) positively correlated to the SRQ (satisfaction) of the preservice teachers

Emerging ecosystem services governance issues in the Belgium Ecosystem Services Community of Practice.

In this paper we will focus on how governance issues are being dealt with in the BElgium Ecosystem Services (BEES) Community of Practice and on some Belgian Ecosystem Services (ES) research projects aimed at policy or practice support. As ES governance is still mainly an aspect of policy or practice oriented research, we will specifically focus on method and methodological decision making. The system or systems we aim to govern are complex. But also the governance processes are inherently complex. How do we take this complexity into account in decision support? Do we acknowledge complexity in our approach or do we drastically simplify and reduce it to relatively simple proportions? The methodological approach of decision support methods is open for debate as neither crystal clear nor undisputed yardsticks for best practices exist. On an ambition level, BEES members generally seem to prefer transdisciplinary as well as inclusive valuation approaches, though not exclusively in all circumstances. In Belgium research projects, similar to the developments within BEES, from a research practice dominated by scientists, gradually research processes are opening up to transdisciplinary collaboration. Simultaneously these processes gradually shift from mainly top down approaches to bottom up approaches or hybrid combinations of both entry points. A closer and more nuanced view shows that real transdisciplinary collaboration in Belgian ES research still is only at the beginning. Partly this can be explained by the fact that inter- and transdisciplinary approaches are perhaps more realistic, but also have to deal with more social complexity. New balances have to be found between sophistication and pragmatics. Also the role of science can become more ambiguous: the closer to stakeholders, the more an independent role can be questioned. Regarding ES valuation methods, in general a trend towards more inclusive valuation is clearly noticeable in Belgian ES research, inclusive in the sense of a diversity of ES valuation aspects to be taken into account, diverse types of expression of value(s), a combination of quantifiable and qualitative information, and a diversity of valuators by way of more bottom-up approaches. Still, there are quite some differences between projects and challenges for integration.SCOPUS: ar.jinfo:eu-repo/semantics/publishe