Sensitivity of plant functional types to climate change: classification tree analysis of a simulation model

Abstract

Question: The majority of studies investigating the impact of climate change on local plant communities ignores changes in regional processes, such as immigration from the regional seed pool. Here we explore: (i) the potential impact of climate change on composition of the regional seed pool, (ii) the influence of changes in climate and in the regional seed pool on local community structure, and (iii) the combinations of life history traits, i.e. plant functional types (PFTs), that are most affected by environmental changes. Location: Fire‐prone, Mediterranean‐type shrublands in southwestern Australia. Methods: Spatially explicit simulation experiments were conducted at the population level under different rainfall and fire regime scenarios to determine the effect of environmental change on the regional seed pool for 38 PFTs. The effects of environmental and seed immigration changes on local community dynamics were then derived from community‐level experiments. Classification tree analyses were used to investigate PFT‐specific vulnerabilities to climate change. Results: The classification tree analyses revealed that responses of PFTs to climate change are determined by specific trait characteristics. PFT‐specific seed production and community patterns responded in a complex manner to climate change. For example, an increase in annual rainfall caused an increase in numbers of dispersed seeds for some PFTs, but decreased PFT diversity in the community. Conversely, a simulated decrease in rainfall reduced the number of dispersed seeds and diversity of PFTs. Conclusions: PFT interactions and regional processes must be considered when assessing how local community structure will be affected by environmental change.

Effects of climate change and urban development on the distribution and conservation of vegetation in a Mediterranean type ecosystem

“…For PFTs I expected resprouters (those species that resprout in response to fire) to be most affected by a drier future climate (Esther et al, 2010), as establishment of resprouter seedlings depends on wet summer conditions the year after a fire (Enright and Lamont, 1992;Enright et al, 1998).…”

Low-dimensional trade-offs fail to explain richness and structure in species-rich plant communities

“…In the following sections, we describe the possible PFTs and processes. A detailed site-specific model description, calibration and comparison with field data can be found elsewhere (Esther et al 2008(Esther et al , 2010.…”

“…We use a negative exponential function with an average dispersal distance d m from the parent to describe the distribution of dispersal distances (Bauer et al 2002;Groeneveld et al 2002;Esther et al 2008Esther et al , 2010. Different values of d m distinguish between short-and long-range dispersal (Table 1).…”

“…Resprouters can survive and re-grow from buried stem tissue after a fire event with a basic fire survival probability p f_surv,b depending on their age a, the time since the last fire (t f ) and the rainfall condition of the current year (Enright et al 1998b;Groeneveld et al 2002;Esther et al 2008Esther et al , 2010): …”

“…The annual rainfall condition (wet, average, dry) is chosen according to a probability distribution generated from rainfall records for 110 years from the closest climate station (Dongara) to the Eneabba field sites with long-term rainfall records. Years are randomly assigned as wet (20% of years), average (55%) or dry (25%) as described in Enright et al (1998a, b), Groeneveld et al (2002) and Esther et al (2008Esther et al ( , 2010.…”