Modelling the potential impact of climate variability and change on species regeneration potential in the temperate forests of South‐Eastern Australia

Abstract

The sensitivity of early plant regeneration to environmental change makes regeneration a critical stage for understanding species response to climate change. We investigated the spatial and temporal response of eucalypt trees in the Central Highland region of south eastern Australia to high and low climate change scenarios. We developed a novel mechanistic model incorporating germination processes, TACA-GEM, to evaluate establishment probabilities of five key eucalypt species, Eucalyptus pauciflora, Eucalyptus delegatensis, Eucalyptus regnans, Eucalyptus nitens and Eucalyptus obliqua. Changes to regeneration potential at landscape and site levels were calculated to determine climate thresholds. Model results demonstrated that climate change is likely to impact plant regeneration. We observed increases and decreases in regeneration potential depending on the ecosystem, indicating that some species will increase in abundance in some forest types, whilst other forest types will become inhabitable. In general, the dry forest ecosystems were most impacted, whilst the wet forests were least impacted. We also observed that species with seed dormancy mechanisms, like E. pauciflora and E. delegatensis, are likely to be at higher risk than those without. Landscape-and site-level analysis revealed heterogeneity in species response at different scales. On a landscape scale, a 4.3°C mean temperature increase and 22% decline in precipitation (predicted for 2080) is predicted to be a threshold for large spatial shifts in species regeneration niches across the study region, while a 2.6°C increase and 15% decline in precipitation (predicted for 2050) will likely result in local site-level shifts. Site-level analysis showed that considerable declines in regeneration potential for E. delegatensis, E. pauciflora and E. nitens were modelled to occur in some ecosystems by 2050. While overall model performance and accuracy was good, better understanding of effects from extreme events and other underlying processes on regeneration will improve modelling and development of species conservation strategies.

Climate change impacts and adaptation in forest management: a review

“…Regionally, there have been relatively few published journal articles on impacts or adaptation in forests in the Southern Hemisphere (Hughes et al 1996;Williams 2000;Pinkard et al 2010;Gonzalez et al 2011;Mok et al 2012;Breed et al 2013), although there have been more studies in the grey literature for Australian forests (Battaglia et al 2009;Cockfield et al 2011;Medlyn et al 2011;Stephens et al 2012). There have been some valuable analyses for the tropics (Guariguata et al 2008(Guariguata et al , 2012Somorin et al 2012;Feeley et al 2012).…”

Landscape Structure and Mature Forest Biodiversity in Wet Eucalypt Forests: A Spatial Analysis of Timber Production Areas in South-Eastern Australia

“…If these reserved forests transition to maturity over time, they may provide important additional habitat to facilitate the recolonisation by mature-forest-associated species of both future coupes and historically harvested coupes. However, in these flammable ecosystems, fires may truncate the transition to maturity and managers should continue to develop strategic planning systems that retain mature forest in parts of the landscape representing the lowest fire risk (e.g., because of landscape position or forest type; [63,79,80]). …”

Germination Phenological Response Identifies Flora Risk to Climate Change

“…The TACA-GEM (Mok et al, [35]) is a modified version of TACA [32][33][34] was used to model the species-specific germination and establishment responses for the assessment of species resiliency to climate change. The model analyses the influence of projected climate change on the ability of a tree species to regenerate and establish.…”

“…The Tree and Climate Assessment (TACA, [32][33][34]) and the Tree and Climate Assessment-Germination and Establishment Module (TACA-GEM [35]) mechanistic models have been largely used to assess the vulnerability of plant species to climate change, modeling the regeneration response. This model primarily utilizes species phenological parameters like growing degree days (GDD), base temperature, chilling requirement, frost, and drought to show the shift in species germination timing under projected climate conditions, that helps in the identification of vulnerable species [35,36].…”

“…A study conducted by Thapa et al [37] also indicates that climate change may adversely affect the lowlands and mid hills, consequently inviting major biodiversity loss in tropical and subtropical broad leaf forests by the 2050s and 2080s in several regions of Nepal [37]. Therefore, the current study explores the effect of projected climate change on regeneration and recruitment phenology of some timber tree species inhabiting tropical/subtropical broad leaf forests, using a forest vulnerability tool: the TACA-GEM mechanistic model [35,36]. Thus, the main objective of the study is to identify the resilient species that can adapt to projected climate change conditions by modeling species regeneration response.…”