A Model of Mosquito–Mangrove Basin Ecosystems with Implications for Management

Abstract

A model of the mosquito-mangrove basin ecosystem is presented detailing the habitat of the saltwater mosquito Aedes vigilax utilizing mangrove basin forests in Australia. The modeling included a synthesis of empirical observations and published descriptions including the insect's relevant lifestages, mangrove basin topography and hydrodynamics. Shallow mangrove basins periodically connected by only the highest 10% of high tides with a hummocky substrate micro-topography characterize the main mangrove form conducive to Ae. vigilax breeding. Other essential features include the synchronization of the mosquito's lifecycle to basin hydrodynamics and thus an intricate relationship between hydrodynamics and basin structure. Very small decreases in basin water level (~1 cm/day) lead to significant decreases in extent of standing water (for example, 60% over 6 days) across the basin. This results in corresponding increases in the extent of exposed substrate. Also, the modeling demonstrated sensitivity of the mosquito- mangrove basin ecosystem to sea level changes. A hydrologic model of the basin was used to predict mosquito breeding episodes which were tested against a mosquito management larviciding program. The model predicted 75% of all 29 larviciding treatments undertaken. Comparing the model against the two triggers used by mosquito control, tides and rainfall, the model predicted 92% of tidally instigated treatments and 60% of rainfall instigated treatments. Application of the model enables consideration of environment-based minimal habitat modification for mosquito control in mangroves, not previously possible. The model will be applicable to similar species, such as Ae. taeniorhynchus, found in Florida's (USA) mangroves.