Biodiversity Consequences of Genetic Variation in Bark Characteristics within a Foundation Tree Species

Abstract

The developing field of community genetics has the potential to broaden the contribution of genetics to conservation biology by demonstrating that genetic variation within foundation plant species can act to structure associated communities of microorganisms, invertebrates, and vertebrates. We assessed the biodiversity consequences of natural patterns of intraspecific genetic variation within the widely distributed Australian forest tree, Eucalyptus globulus. We assessed genetic variation among geographic races of E. globulus (i.e., provenances, seed zones) in the characteristics of tree-trunk bark in a 17-year-old common garden and the associated response of a dependent macroarthropod community. In total, 180 macroarthropod taxa were identified following a collection from 100 trees of five races. We found substantial genetically based variation within E. globulus in the quantity and type of decorticating bark. In the community of organisms associated with this bark, significant variation existed among trees of different races in composition, and there was a two-fold difference in species richness (7-14 species) and abundance (22-55 individuals) among races. This community variation was tightly linked with genetically based variation in bark, with 60% of variation in community composition driven by bark characteristics. No detectable correlation was found, however, with neutral molecular markers. These community-level effects of tree genetics are expected to extend to higher trophic levels because of the extensive use of tree trunks as foraging zones by birds and marsupials. Our results demonstrate the potential biodiversity benefits that may be gained through conservation of intraspecific genetic variation within broadly distributed foundation species. The opportunities for enhancing biodiversity values of forestry and restoration plantings are also highlighted because such planted forests are increasingly becoming the dominant forest type in many areas of the world.

Community Genetic and Competition Effects in a Model Pea Aphid System

“…This pattern is consistent with other community genetic studies where the genotype of the dominant species influences both the presence and abundance of species in the plantassociated community (e.g. Johnson and Agrawal, 2005;Johnson et al, 2006;Whitham et al, 2003Whitham et al, , 2006, see also Barbour et al, 2009).…”

Genetic variation in a tropical tree species influences the associated epiphytic plant and invertebrate communities in a complex forest ecosystem

“…Within temperate ecosystems, genetic variation within a dominant plant species can influence the structure of the associated invertebrate [8][9][10][11][12][13][14][15][16][17], plant [18], endophytic fungi [19] and vertebrate [20,21] communities. An important factor in these interactions has been found to be plant biochemistry.…”

Compromising genetic diversity in the wild: unmonitored large-scale release of plants and animals

“…Barbour et al [66,67] examined the effects of genetic variation in Eucalyptus globulus on dependent biodiversity. They studied 160 trees representing eight races in a 15-year-old common garden, and showed that genetic composition of trees affects species occurrence and composition of a number of other groups of organisms including arthropods, fungi, snails and spiders, not only on the living trees but also in the associated litter.…”