Contributions of microenvironmental variation to population persistence

The environment can vary at small spatial scales, so small that neighbouring plants in a natural population can grow with different resource levels and experience different degrees of competition. This fine-grained biotic and abiotic variation in the environment could favour the maintenance of genetic diversity within populations. Yet, ecological and evolutionary studies often ignore the effects of micro-environment on plant population and community dynamics. Climate change is also rapidly altering complex suites of environments to which natural populations have adapted.

Examples of micro-environmental variation. (A) Soil ionic properties change drastically, as shown by zeolite outcrops in south-eastern Oregon, USA. (B) Slope and aspect influence light intensity along the Snake River, Idaho, USA. (C) Surface temperatures and soil depth are affected by the granite outcrops of Rock and Shoals, Georgia, USA. (D) The Tierra Amarilla Anticline of northern New Mexico, USA, is composed of sandstone and gypsum soils, which affect water availability to plants. Image credit: Denney et al.

In a new review published in AoBP, Denney et al. discuss the influence of the microenvironment on plant physiology, adaptation and plasticity in the context of novel and rapidly changing environments. The authors consider the role of microenvironments as paleo-refugia during historic climate shifts, and the potential of existing variation in the microenvironment to serve as refugia under contemporary climate change. The authors highlight that if microrefugia sustain local populations in the short term, other eco-evolutionary processes, such as gene flow and adaptation, could enhance population stability in the longer term. They caution, however, that local populations may still decline in size as they contract into rare microhabitats and microrefugia. They hope that their review will open the door to future work that explicitly examines the role of the micro-environment in maintaining genetic variation within local populations. They also hope that conservation management will benefit from a better understanding of the roles of microrefugia in a plant species’ perseverance to climate change.

This article was published in the AoBP Special Issue entitled The Ecology And Genetics Of Population Differentiation In Plants.