The importance of genetic diversity in plant conservation

When I talk about my work as a scientist in the Research and Conservation Department at Denver Botanic Gardens, I explain how I study the role of genetic diversity in conserving biodiversity. People often ask for examples of this or cite famous stories of disease resistance, genetic rescue or environmental adaptation. Indeed, there are great examples, such as how a lack of genetic diversity led to widespread disease and die-off of potato crops resulting in the 1800s Irish Potato Famine, or the successful recovery of the endangered Florida panther after introduction of new genetic variation from Texas panthers. I want to highlight a few real-world examples that are specific to plant biodiversity conservation. 

First, adaptation to new environments is facilitated by genetic diversity. Examples of this include colonization of toxic mine tailings by certain grass species (e.g. Anthoxanthum odoratum), adaptation of yarrow (e.g. Achillea borealis) and other species to serpentine (low nutrient, high heavy metal) soils, and existence of new species or varieties of wild sunflowers (e.g. Helianthus petiolaris) in sand dune habitats. These studies of natural phenomena are particularly valuable to understand in the context of conserving biodiversity under ongoing threats of environmental change. 

Second, genetic diversity can increase ecosystem function. While the mechanisms for this are still debated, there is ample evidence that complementarity, or differential strategies by different species or genetic variants, allows for improved functioning of ecosystems. In grasslands for example, it has been shown that species that utilize above- versus below-ground space in complementary ways results in higher productivity overall. Or in the case of threats such as herbivores and climate extremes, different plant species can protect or facilitate each other via mechanisms such as nurse plant effects. Together, these examples emphasize the role of genetic diversity in plant communities and the importance of conserving it.