Genetic Diversity Parameters Associated with Viability Selection, Reproductive Efficiency, and Growth in Forest Tree Species

Biological diversity, “biodiversity” for short (e.g., Wilson 1988), encompasses all levels of the variability of life, i.e., the diversity within species, among species, among ecosystems, and among biomes. Our contribution addresses the genetic variation within species (intraspecific biodiversity, commonly designated as “genetic diversity”) which is quantified as variation within populations (within and among individuals), among populations, and within metapopulations. The study of functions of biodiversity may follow a hierarchical structure, i.e., coding genes, individuals, ecotypes, species, and various other biological communities. Functionally relevant are also the dynamics of populations and species in time and space, as well as specific characteristics such as abundance, evenness, and reproducibility. At the species level, genetic variation of populations – particularly their potential to create genetic variation (“genetic variability”) – may play a major role in their ability to adapt to heterogeneous environmental conditions and unpredictable host–parasite interactions. Genetic variability is expected to determine the totality of adaptive abilities of populations (e.g., Gregorius 1991; Ziehe et al. 1999). In addition, genetic variation is expected to be correlated with fitness in various plant and animal species (Mitton and Grant 1984; Allendorf and Leary 1986). Biodiversity can also be considered as being redundant (e.g., Lawton and Brown 1993; Yachi and Loreau 1999). The question of whether or not genetic variation (variability) can be expected to be redundant refers to various components of the genetic system of a species including reproduction, gene flow, and the response to stress, but this question has not yet been studied in detail. Concerning functions of biodiversity, forest ecosystems (i.e., natural forests and forest plantations) have a high indicative value because of their longevity compared to other plant species and the wide range of occupied