The use of demographic sensitivity analysis in marine species conservation planning

We explore the idea that a sensitivity analysis conducted on stage-specific demographic rates can be used to improve our ability to determine the efficacy of conservation plans that are designed to enhance the recovery of individual marine species. Because a given reserve may not be able to protect all life stages and habitats for wide-ranging marine organisms, reserves should target life history stages for which protection will foster the highest population growth rates. Likewise, it should be recognized that reserves designed to reduce mortality of a particular life stage, such as adults that are the focus of a fishery, will benefit some life history types more than others. For a representative range of marine life histories, we found that the change in λ resulting from a decrease in adult mortality varied for each species considered, with the largest positive impact on population growth in marine invertebrates and fish and lowest in species with very low adult mortality rates. Results from analyses of both mortality elasticity and absolute change in λ resulting from a decrease in adult mortality were highly correlated with adult survival rate and maximum fecundity, and also showed a significant relationship with age at sexual maturity, longevity and juvenile survival. Standardized demographic analysis may be a useful first step to compare disparate conservation goals for marine reserve design for species with distinct life histories.