Living (and reproducing) on the edge: reproductive phenology is impacted by rainfall and canopy decline in a Mediterranean eucalypt

Abstract

Many of the worlds' forests and woodlands are currently showing symptoms of declining condition due to a range of factors, including changing climatic conditions, drought, and insect herbivory. Altered abiotic and 25 biotic conditions can influence the condition of trees which can, in turn, affect tree reproductive cycles.However, the potential impact of tree decline on reproductive cycles has rarely been examined. This study investigated the influence of canopy condition on the reproductive cycle of Eucalyptus wandoo in southwestern Australia. Canopy and seed trap monitoring were used to assess bud production, flowering, fruiting and seed fall over 12 months at 24 sites across two locations (Dryandra Woodland and Wandoo 30 Conservation Park). Time since last fire, rainfall, ambient temperatures and the condition of individual trees were recorded. We found that bud production, flowering and fruiting was correlated with tree condition:healthier trees were generally associated with higher reproductive effort. Time since last fire was also strongly related to the reproductive efforts at both locations. Declining annual rainfall and increased temperatures also an impact on reproduction, made evident by the aborted flowering in Dryandra Woodland. 35Decline in tree condition, coupled with changes in climate, have major implications for flowering phenology of this species and have the potential to alter reproductive effort, recruitment, and future population dynamics. Consideration of these issues should be incorporated into the conservation management of E.wandoo and similar Eucalypt species. 40

From Drones to Phenotype: Using UAV-LiDAR to Detect Species and Provenance Variation in Tree Productivity and Structure

“…Such stress would be consistent with the poorer survival reported for the lower altitude provenances at the study site [15]. Eucalypts are ever-green trees and crown density is commonly assessed as an indicator of their health, including defoliation due to pests and drought stress [44,45] and, while normally assessed on an ordered categorical scale, it has been shown to vary among provenances in field trials [46]. Indeed, these differences in crown densities are now raising new hypotheses on the extent to which they may affect the dependent communities through changes in resource use and animal feeding/nesting behaviour.…”

Plant diversity on the edge: floristics, phytogeography, fire responses, and plant conservation of Two Peoples Bay Nature Reserve in the context of OCBIL theory

“…In terms of global warming and climate change, accumulated evidence suggests that drought stress in Eucalyptus wandoo can cause little to no flowering and reduced reproductive output at Dryandra Woodland and Wandoo Conservation Park in the SWAFR (Moore et al 2016). Such effects are compounded by the impact of fire on flowering in C. calophylla in the same forests inland from Perth.…”