A spatially explicit computer model for immature distributions of Glyptotendipes paripes (Diptera: Chironomidae) in central Florida lakes

Abstract

Density and spatial distribution data of immature Glyptotendipes paripes Edwards (Diptera: Chironomidae), in relation to selected water and sediment characteristics prevailing in three central Florida lakes, were used to develop and calibrate a qualitative model of G. paripes distributions with the purpose of developing more efficient sampling plans for research or population management. For the model, each lake habitat was defined by a two-dimensional matrix, while a three-dimensional matrix was used to simulate the life stage-structured population. A Lefkovitch population matrix was used to project survival and development of the population in each spatial unit. The model incorporated lake bathymetry, sediment dry weight, water level, food availability (as a function of Secchi disk transparency) and strength of density dependence as influences on immature survival and adult fecundity. Temperature-dependent development data for G. paripes were incorporated to estimate development time. A simple redistribution function was used to simulate the dispersal of adults over the simulated habitat for oviposition. Immatures and relevant environmental data taken for eight dates, at each of two other central Florida lakes were used to validate the model. The mean correct prediction rate of the model for field density distributions within 0.5 log(n+1) immatures/m2 density in spatial habitat cells was 0.64 and 0.66 for the validation lakes. Presence/absence correct prediction rates were 0.61 and 0.76, while matching to a proposed sampling stratification based on a treatment threshold was 0.85 and 0.88. These values indicate that the model is efficient for preparing stratified immature G. paripes sampling plans for central Florida lakes.