Drivers of functional diversity in native Ericaceae species across Nova Scotia

Abstract

Plant functional diversity is defined by variation in morphological, chemical, or phenological characteristics that influence the way a plant functions. Variation in such traits across different species can be influenced by evolutionary history and environmental factors. Functional traits can also vary within species, and the level of within-species trait plasticity can vary among species and habitats. This study investigates the relative influence of evolutionary history and environmental variation (light, nutrient availability, water) in driving plant functional diversity across 24 species from the Ericaceae family. Plants were sampled across three habitat types (barren, bog, and forest) in Nova Scotia. Morphological traits measured were specific leaf area (SLA), leaf dry matter content (LDMC), leaf thickness (Lth), leaf size (LS), and leaf arrangement (alternate or opposite). Chemical traits measured were leaf pH, and phenological traits were leaf lifespan (evergreen or deciduous) and flowering strategy (precocious or serotinous). Leaf arrangement, leaf lifespan, and leaf pH were influenced by evolutionary history, but the relative influence of evolutionary history was weaker at the family level than at a broader taxonomic scale. All traits were influenced by environmental factors and all traits except leaf pH and leaf arrangement are likely driven more by variation in light than soil water availability. In addition, some species exhibited higher trait plasticity than others. Understanding which environmental factors influence traits, which species had higher levels of plasticity, and the role that evolution and the environment play in shaping those traits is important to understand how species will cope with increasing environmental pressures from climate change.