Leaf trait variability explains how plant community composition changes under the intense pressure of deer herbivory

• Published in: Ecological research Vol. 36; no. 3; pp. 521 - 532
• Main Authors: Wakatsuki, Yuki, Nishizawa, Keita, Mori, Akira S.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.05.2021; Blackwell Publishing Ltd
• Subjects: Carbon fixation; Community composition; Composition; deer herbivory; Dry matter; Dry matter content; Ecosystem disturbance; Forest floor; Forest management; Herbivores; Herbivory; Interspecific; intraspecific trait variation; Leaf area; Leaves; plant carbon economy; Plant communities; plant community; Plant populations; Plant species; plant strategy; Plants; Species composition; Species diversity; Understory; Variation
• ISSN: 0912-3814; 1440-1703
• DOI: 10.1111/1440-1703.12224

There is growing evidence indicating that intraspecific trait variation (ITV) plays a prominent role in determining plant community composition. In this study, we investigated the significance of ITV in identifying the processes that shape the development of forest understory plant communities in an area in which excessive herbivory by overabundant deer populations has been an issue. We measured functional traits (height, leaf area, leaf mass per area, leaf dry matter content, and leaf toughness) of 13 forest floor plant species growing in two contrasting sites in which deer were overabundant or had been completely excluded, respectively, and examined the relationships between species dominance and interspecific trait variation and ITV. We detected variations in the trait plasticity of size and morphological features among species, reflecting species‐specific strategies in response to herbivory and consequently observed marked differences in species composition and diversity at the two sites. Notably, small stature and less costly leaves were identified as important traits that enable plants to persist under conditions of intense deer herbivory probably because such plants are less exposed to herbivory and simultaneously optimize carbon assimilation. In contrast, large‐sized plants with costly leaves tended to dominate the plant community in the absence of deer herbivory, as these plants would tend to gain a competitive advantage with respect to the acquisition of space and light. The findings of this study indicate that a focus on ITV represents a promising approach for determining the general ecological patterns of plant communities responding to environmental disturbance. We examined how deer herbivory effects the assembly process of forest floor plant community by observing both inter‐ and intraspecific trait variabilities in the Shiretoko National Park in Japan. Our results highlight plant forms advantageous for survival vary depending on deer presence/absence. Our study suggests that shedding further light on intraspecific trait variations is a promising approach that can help us disentangle how plant community responds to environmental disturbance.