Environmental effects on growth phenology of co-occurring Eucalyptus species

Abstract

Growth is one of the most important phenological cycles in a plant's life. Higher growth rates increase the competitive ability, survival and recruitment and can provide a measure of a plant's adaptive capacity to climate variability and change. This study identified the growth relationship of six Eucalyptus species to variations in temperature, soil moisture availability, photoperiod length and air humidity over 12 months. The six species represent two naturally co-occurring groups of three species each representing warm-dry and the cool-moist sclerophyll forests, respectively. Warm-dry eucalypts were found to be more tolerant of higher temperatures and lower air humidity than the cool-moist eucalypts. Within groups, species-specific responses were detected with Eucalyptus microcarpa having the widest phenological niche of the warm-dry species, exhibiting greater resistance to high temperature and lower air humidity. Temperature dependent photoperiodic responses were exhibited by all the species except Eucalyptus tricarpa and Eucalyptus sieberi, which were able to maintain growth as photoperiod shortened but temperature requirements were fulfilled. Eucalyptus obliqua exhibited a flexible growth rate and tolerance to moisture limitation which enables it to maintain its growth rate as water availability changes. The wider temperature niche exhibited by E. sieberi compared with E. obliqua and Eucalyptus radiata may improve its competitive ability over these species where winters are warm and moisture does not limit growth. With climate change expected to result in warmer and drier conditions in south-east Australia, the findings of this study suggest all cool-moist species will likely suffer negative effects on growth while the warm-dry species may still maintain current growth rates. Our findings highlight that climate driven shifts in growth phenology will likely occur as climate changes and this may facilitate changes in tree communities by altering inter-specific competition.

Models of Eucalypt phenology predict bat population flux

“…; Rawal et al. , ,b, ). The combined effect of habitat fragmentation and climate changes may be decreased abundance, increased spatial heterogeneity, and increased asynchrony of nectar resources.…”

Climate and competition affect growth and survival of transplanted sugar maple seedlings along a 1700‐km gradient

“…Over the long term, climate‐mediated effects on phenology and growth may shift the competitive balance between species (Savage and Cavender‐Bares , Rawal et al. ), which in turn has the potential to influence species’ distributions (Chuine and Beaubien ). Future studies of tree species’ range limits should compare the phenology and reproductive success of mature stands within the range and near range margins and examine the focal species’ phenology and reproductive success relative to that of other competing species in the forest community.…”

Thermal Requirements and Photoperiod Influence in the Leaf Development of Two Forest Species

“…However, there is no confirmation of the influence of photoperiod on LD in forest species, such as eucalyptus (Rawal et al, 2015). This information could help improving the quality of seedlings and increase the probability of success in the implantation and establishment of forests (Martins et al, 2007;Rawal et al, 2014;Ferreira et al, 2019).…”

“…One of the ways to identify the influence of photoperiod is through field experiments with several sowing dates throughout the year (Rosa et al, 2009). Some studies have reported the effect of photoperiod on the flowering and germination of woody species (Rawal et al, 2014). However, there is no confirmation of the influence of photoperiod on LD in forest species, such as eucalyptus (Rawal et al, 2015).…”