Annales Zoologici Fennici 

About: Annales Zoologici Fennici is an academic journal published by Finnish Zoological and Botanical Publishing Board. The journal publishes majorly in the area(s): Population & Predation. It has an ISSN identifier of 0003-455X. Over the lifetime, 1307 publications have been published receiving 37371 citations.

The adaptive significance of schooling as an anti-predator defense in fish

Abstract: Recent experiments have demonstrated the adaptive advantages of schooling behav iour during predator defence. Fish in schools benefit from increased vigilance and, as a consequence of inspection behaviour, predator recognition and assessment is im proved. Information about advancing predators can be obtained from other school members without each fish needing to independently confirm the extent of the danger. Schooling behaviour and inspection behaviour may inhibit attack by predators, and, if schools are attacked a variety of tactics, ranging from the confusion effect to the flash expansion, serve to protect individual members. There are however a number of constraints on the evolution of schooling and asso ciated anti-predator mechanisms. For instance, conflicting selection pressures, such as the need to forage, mate and avoid predation, can operate simultaneously. Selection pressures acting on immature and adult fish may be discontinuous necessitating a period of increased vulnerability when individuals switch tactics. Schooling may not be an equally appropriate defence against all predators and the phylogenetic origins of populations or species can lead to additional genetic constraints. It seems probable that behavioural ecologists will increasingly focus on how interactions between such con straints govern the evolution of behaviour.

Extinction debt and species credit in boreal forests: modelling the consequences of different approaches to biodiversity conservation.

Abstract: The extinction debt of boreal forest species is estimated to be of the order of 1 000 species in Finland. Using a spatially explicit metapopulation model, this paper examines the likely consequences for the survival of species of different scenarios of forest management and conservation. The results point to the conclusion that it generally pays to concentrate the efforts of improving forest quality at certain areas rather than to spread the same total effort evenly and therefore thinly throughout the entire forest landscape. The practical conclusion is that in southern Finland an extensive restoration program of managed forests to natural-like successional forests is needed to avert the imminent wave of extinctions of specialist forest species. The greatest positive effect is obtained if forests located close to the existing remnants of biologically diverse forests are restored, which would facilitate the migration of target species to the restored forests.

Patch use under predation risks. I : Models and predictions

Abstract: Patch use under predation risk requires animals to trade off needs for safety and food. I consider within a common framework four ways of modeling how safety and energy influence fitness. These models make similar predictions for when a forager should stop feeding from depletable patches that vary in predation risk. In accord with Brown (1988), patches should be abandoned when the harvest rate no longer compensates for the metabolic, predation, and missed opportunity costs of foraging. In accord with Gilliam & Fraser (1987), safe and risky patches should be left at the same ratio of predation risk to net feeding rate when the alternative activities include resting in a safe refuge to save energy. The quitting harvest rate of the forager within a food patch should be sensitive to predation risk and to the marginal value of food (the fitness value of an additional food item). Quitting harvest rates should be higher in food patches with higher predation risk. Quitting harvest rates and the costs of predation should increase as the marginal value of food decreases. The difference in quitting harvest rates between patches with high and low predation risk should increase as the marginal value of food decreases. Fortunately, the shared qualitative predictions of these models have and can be tested. Unfortunately, distinguishing among the models' differing quantitative predictions shall prove challenging.