Kin structure and genotype‐dependent mortality: a study using the neotropical tree Caryocar brasiliense

Abstract

Summary 1. In many species, density‐dependent processes regulate population size through size‐ and neighbourhood‐dependent mortality. 2. If a kin structure exists in a particular population, mortality may be spatially clustered due to enhanced competition among relatives. 3. Demography, kin structure and genetic diversity, based on 10 microsatellite loci, of a local population of the Neotropical tree Caryocar brasiliense were studied for 23 years. Overall population growth was static (λ = 1.0) during this time, but some time intervals showed negative growth. 4. Mortality was spatially clustered and negatively correlated with spatial distance among pairs of individuals at distances lower than c. 13 m. Probability of death was related to individual genotypes, and seedlings and juveniles with lower proportion of heterozygous loci had the highest probability of mortality. 5. Kinship was significantly related to spatial distance among pairs of individuals at distance lower than 10 m and kinship structure did not change along the life stages, but the inbreeding coefficient was not significantly different from zero in adults. 6. Synthesis. We hypothesize that genetic clustering in C. brasiliense dissipates over time due to more intense competition among relatives. Thus, the kin structure in C. brasiliense is highly important in determining mortality patterns, driving the spatial pattern in plant recruitment.