SIMSPAR - Decision Based Flow Chart

Flow Chart of Decisions

A detailed approach to modeling the Cape Sable Seaside Sparrow population is feasible because the main threat to the population is disruption of reproduction due to the flooding of nesting areas which can be simulated through hydrologic modeling. The behavior of the sparrows during reproduction and the influence of water levels on the initiation and successful completion of reproductive behavior are relatively well known from field studies. Additionally, the water levels in the sparrow's range can be predicted at a fine enough temporal and spatial scale to be explicitly modeled. Since the sparrow's population is affected by landscape level changes in water level which vary dramatically through time, a spatially expilict population model represents a realistic approach for combining individual sparrow behavior with landscape level elements.

The flow chart, at left, represent the series of decisions that an individual male sparrow makes during the course of a year. At the beginning of the season, SIMSPAR determines whether each individual male was unmated or mated during the previous season. Unmated males are those that were "floater" males or those males that fledged during the previous season. Unmated or unsuccessful males search the area for suitable unoccupied breeding sites. If they find a territory, they will sing and attempt to mate. Those males that successfully mated during the previous season will mate with the same females in the same territories. Once the individuals are mated, they will attempt to breed. If during the breeding season the water level within their territory raises above the nesting height, the sparrows will desert the nest. Once the brood has successfully reared or the nest deserted, the sparrow pair will attempt another nest if the breeding season has not yet ended. The overwintering season is not modeled explicitly by SIMSPAR.

By following a set of logical decisions, SIMSPAR models each of the individual sparrows across the landscape. These sparrow interact with other individuals as well as the environment. The sum total of all individual decisions made determines the breeding success of the population and subsequently population size.



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