Response of past and present Mediterranean ecosystems to environmental change

Allen, Harriet

doi:10.1191/030913303767888482

Cited by 37 publications

(20 citation statements)

References 24 publications

(32 reference statements)

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“…Such questions appear particularly important in the spatially heterogeneous mountainous and Mediterranean environments where climatic change is known to be higher and faster than in other contexts (Allen 2003;Giorgi and Lionello 2008;Goubanova and Li 2007) and forest ecosystems extremely vulnerable to environmental changes (Gaucherel et al 2008;Lindner et al 2010). Over the present century, climatic models predict an increase in temperature (?2 to ?4°C) and a decrease in precipitation (except in winter) (Giorgi and Lionello 2008).…”

Section: Introductionmentioning

confidence: 98%

Instability of climate signal in tree-ring width in Mediterranean mountains: a multi-species analysis

Lebourgeois¹,

Mérian²,

Courdier³

et al. 2011

Trees

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Temporal instability of climate signal in treering width of the five dominant species (Pinus nigra, P. sylvestris, P. uncinata, Abies alba, Fagus sylvatica) growing under Mediterranean mountainous climate was studied over the last century . To disentangle the tree-climate-site complex, the effects of both soil water availability (SWA) (dry, mesic and humid sites) and altitude (from 430 to 1,690 m) were investigated on the response patterns. Responses to climate were analysed using bootstrapped correlation coefficients from 17 ring-

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Section: Introductionmentioning

confidence: 98%

Instability of climate signal in tree-ring width in Mediterranean mountains: a multi-species analysis

Lebourgeois¹,

Mérian²,

Courdier³

et al. 2011

Trees

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“…Mediterranean-climate ecosystems are characterised by warm, dry summers and cool, wet winters, with the water limitation associated with the normal dry season a major constraint to plant growth and survival (Allen 2003). Global forecasts of rising temperatures and increasing aridity are likely to exacerbate these limitations and impact severely on plant diversity in these disturbance-prone ecosystems (Klausmeyer and Shaw 2009).…”

Section: Introductionmentioning

confidence: 99%

The phenotypic response of co-occurring Banksia species to warming and drying

et al. 2014

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Projected warmer and drier climates are expected to impact heavily on plant diversity in Mediterranean-climate ecosystems, but experimental investigations of sensitivity and adaptive capacity are needed to better understand species responses. Here, we examine the effects of warming and drying on growth and allocation in seedlings from populations of two co-occurring Banksia shrub species from southwest Western Australia. We hypothesised that the species would show ecological divergence in functional traits reflecting niche differentiation. We expected to see tolerance to warming and drought correlated with position of the population on a climate gradient. We predicted that populations at the warmer/ drier end of the gradient would show greater homeostasis of growth and allocation patterns in response to experimental treatment. Seedlings of the two species differed in leaf and allocation traits and in responses to experimental warming and drying. B. coccinea had smaller leaves with higher specific leaf area, and accumulated less overall biomass compared to B. baxteri when grown under cooler conditions. Under warmer conditions, B. coccinea could maintain growth, whereas B. baxteri suffered significant decline in biomass accumulation. Under water deficit conditions, both species showed significant reductions in leaf mass and area. Under combined warmer/drier conditions B. baxteri forfeited height growth and biomass and increased leaf allocation. The results support our hypothesis that seedlings of B. baxteri and B. coccinea are divergent in key functional traits and their sensitivity to warming and drying. However, we found no evidence for inter-population variation in traits being associated with position on a climate gradient.

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“…Fire-prone, species-rich Mediterranean regions of the world with their cool wet winters and hot dry summers have been recognized as potentially highly vulnerable to climate change (Allen 2003;Cowling et al 2004). Increasing temperatures and changes in amount and variability of rainfall may also alter fire frequency, further endangering this rich plant diversity (Pittock 2003;Pitman et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Seed-based approach for identifying flora at risk from climate warming

Cochrane¹,

Daws

Hay

2010

Austral Ecology

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In obligate seeding species, the germination niche is crucial for colonization and population survival. It is a high-risk phase in a plant's life cycle, and is directly regulated by temperature. Seeds germinate over a range of temperatures within which there is an optimum temperature, with thresholds above and below which no germination occurs. We suggest that abrupt changes in temperature associated with a warming climate may cause a disconnect between temperatures seeds experience and temperatures over which germination is able to occur, rendering obligate seeding species vulnerable to decline and extinction. Using a bidirectional temperature gradient system, we examined the thermal constraints in the germination niche of some geographically restricted species from the low altitude mountains of the Stirling Range, southern Western Australia, including seedlots from lowland populations of four of these species. We demonstrated that high temperatures are not a limiting factor for germination in some restricted species, signifying a lack of relationship between geographic range size and breadth of the germination niche. In contrast, we identified other restricted species, in particular Sphenotoma drummondii, as being at risk of recruitment failure as a consequence of warming: seeds of this species showed a strong negative relationship between percentage germination and increasing temperature above a relatively low optimum constant temperature (13°C). We found some ecotypic differences in the temperature profiles between seeds collected from montane or lowland populations of Andersonia echinocephala, and while specific populations may become more restricted, they are perhaps at less risk of extinction from climate warming.This seed-based approach for identifying extinction risk will contribute tangibly to efforts to predict plant responses to environmental change and will assist in prioritizing species for management actions, directing limited resources towards further investigations and can supplement bioclimatic modelling.

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Response of past and present Mediterranean ecosystems to environmental change

Cited by 37 publications

References 24 publications

Instability of climate signal in tree-ring width in Mediterranean mountains: a multi-species analysis

Instability of climate signal in tree-ring width in Mediterranean mountains: a multi-species analysis

The phenotypic response of co-occurring Banksia species to warming and drying

Seed-based approach for identifying flora at risk from climate warming

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