Improving the efficiency of augmentative biological control with arthropod natural enemies : A modeling approach
Plouvier, Wouter N. ; Wajnberg, Eric - \ 2018
Biological Control 125 (2018). - ISSN 1049-9644 - p. 121 - 130.
Behavioral ecology - Cost efficiency - Genetic algorithm - Individual-based model - Life-history traits - Natural enemies
A better understanding of the life-history traits of biocontrol agents and their effect on population dynamics is key to obtaining more efficient pest control and generating higher economic returns for biocontrol practitioners. To this end, we constructed an optimality simulation model based on principles of the behavioral ecology of natural enemies. This model allows for the identification of the most important life-history traits of natural enemies (e.g., fecundity, longevity, attack rate, competition and dispersal), taking into account the costs and benefits for biocontrol practitioners. The model was kept general and was designed in such a way that it can be adapted to different target species and their specific ecology (natural enemy-pest-plant combination). Results indicate strong interactions between the optimized life-history traits of the biocontrol agents. Two different optimized life-history strategies for the agents were found with higher potential economic returns. These strategies differ most significantly in the plant-leaving decision and host handling time of the biocontrol agent, but also in their respective fecundity, longevity and dispersal ability. The preferred strategy depends on the number of agents released and the growth rate of the plant. Information from these optimality models can help to determine which agents should be released and how they should be released in a specific agro-ecological situation.
Harbour porpoise movement strategy affects cumulative number of animals acoustically exposed to underwater explosions
Aarts, Geert ; Benda-Beckmann, Alexander M. Von; Lucke, K. ; Özkan Sertlek, H. ; Bemmelen, Rob Van; Geelhoed, Steve C.V. ; Brasseur, Sophie ; Scheidat, Meike ; Lam, Frans Peter A. ; Slabbekoorn, Hans ; Kirkwood, Roger - \ 2016
Marine Ecology Progress Series 557 (2016). - ISSN 0171-8630 - p. 261 - 275.
Acoustics - Anthropogenic sound - Cumulative effects - Impact assessment - Individual-based model - Marine mammals - Population consequences of disturbance - Species distribution
Anthropogenic sound in the marine environment can have negative consequences for marine fauna. Since most sound sources are intermittent or continuous, estimating how many individuals are exposed over time remains challenging, as this depends on the animals' mobility. Here we explored how animal movement influences how many, and how often, animals are impacted by sound. In a dedicated study, we estimated how different movement strategies affect the number of individual harbour porpoises Phocoena phocoena receiving temporary or permanent hearing loss due to underwater detonations of recovered explosives (mostly WWII aerial bombs). Geo-statistical distribution models were fitted to data from 4 marine mammal aerial surveys and used to simulate the distribution and movement of porpoises. Based on derived dose-response thresholds for temporary (TTS) or permanent threshold shifts (PTS), we estimated the number of animals affected in a single year. When individuals were free-roaming, an estimated 1200 and 24 000 unique individuals would suffer PTS and TTS, respectively. This equates to respectively 0.50 and 10% of the estimated North Sea population. In contrast, when porpoises remained in a local area, fewer animals would receive PTS and TTS (1100 [0.47%] and 15 000 [6.5%], respectively), but more individuals would be subjected to repeated exposures. Because most anthropogenic sound-producing activities operate continuously or intermittently, snapshot distribution estimates alone tend to underestimate the number of individuals exposed, particularly for mobile species. Hence, an understanding of animal movement is needed to estimate the impact of underwater sound or other human disturbance.