Do freeze events create a demographic bottleneck for Colophospermum mopane?

Whitecross, M.A.; Archibald, Sally; Witkowski, E.T.F.

doi:10.1016/j.sajb.2012.07.008

Cited by 35 publications

(45 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Whitecross et al . () in their case study on the impact of frost on Colophospermum mopane in South Africa proved that frost resembles a disturbance regime maintaining saplings in a ‘freeze trap’ similar to the often cited ‘fire trap’ and ‘browse trap’. Furthermore, they found evidence that topographic position in the landscape has an influence on the severity of frost damage.…”

Section: Frost As a Major Ecological Drivermentioning

confidence: 92%

See 1 more Smart Citation

Climate refugees going underground – a response to Maurin et al. (2014)

2016

View full text Add to dashboard Cite

Section: Frost As a Major Ecological Drivermentioning

confidence: 92%

“…Impact of frost on southern African savanna ecosystems has been documented by several authors (Holdo, ; Chafota & Owen‐Smith, ; Whitecross et al ., ). Whitecross et al .…”

Section: Frost As a Major Ecological Drivermentioning

confidence: 97%

Climate refugees going underground – a response to Maurin et al. (2014)

2016

View full text Add to dashboard Cite

“…In severe cases this damage can lead to tissue necrosis and leaf abscission, followed by topkill (death of the aboveground parts) or even whole-plant mortality (Ball et al, 1991;Holdo, 2006;Wakeling et al, 2012;Whitecross et al, 2012). The occurrence of frost can thus be an important localised factor involved in distribution of plant species, a known phenomenon in African Savannas (Holdo, 2006;Wakeling et al, 2012;Whitecross et al, 2012). In this study we test the hypothesis that the local distribution of frost determines where spekboom can grow.…”

Section: Introductionmentioning

confidence: 99%

“…This may lead to photoinhibition upon illumination and rapid declines in photosynthetic efficiency (F v / F m ), and an inability to quench captured radiant energy (Pearce, 2001;Ehlert and Hincha, 2008;Sonoike, 2011). In severe cases this damage can lead to tissue necrosis and leaf abscission, followed by topkill (death of the aboveground parts) or even whole-plant mortality (Ball et al, 1991;Holdo, 2006;Wakeling et al, 2012;Whitecross et al, 2012). The occurrence of frost can thus be an important localised factor involved in distribution of plant species, a known phenomenon in African Savannas (Holdo, 2006;Wakeling et al, 2012;Whitecross et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Frost, Portulacaria afra Jacq., and the boundary between the Albany Subtropical Thicket and Nama-Karoo biomes

Duker

Cowling

Preez

et al. 2015

South African Journal of Botany

View full text Add to dashboard Cite

a b s t r a c t a r t i c l e i n f o Available online xxxx Edited by WJ BondNumerous shrublands exist in areas where soil moisture should support tree growth. In South Africa, the dwarf shrublands of the Nama-Karoo biome and tree-dominated vegetation of the Albany Subtropical Thicket biome share a boundary that is often abrupt. This boundary is not associated with edaphic or rainfall transitions. Field observations and leaf-level experiments suggest that the vulnerability of thicket species to frost damage is responsible for this thicket-shrubland boundary. We tested this hypothesis by establishing cuttings of Portulacaria afra (spekboom) -a dominant thicket succulent shrub that is a keystone species in arid forms of thicket -in two separate transplant experiments. Firstly across a topographic gradient from frost-free, thicket clad slopes to frostprone, karoo shrubland dominated valley floor; and secondly, inside and outside a thicket clump in the frostprone valley floor. We quantified the effects of frost on spekboom by measuring photosynthetic efficiency (F v / F m ), leaf number, estimating the percentage of healthy stem before and after frost events in June 2013. Frost-exposed spekboom cuttings rapidly underwent declines in photosynthetic efficiency, followed by severe leaf and stem necrosis; herbivores played no role in these declines. Those planted on the frost-free valley slopes or under the frost-protecting thicket canopy on the valley floor remained largely unaffected. This supports the hypothesis that frost-exposure is likely to be the main factor determining the growth rates, and ultimately survival of spekboom. These results suggest that frost occurrence is an important factor involved in determining the boundaries between the arid, and spekboom-rich subtypes of Albany Subtropical Thicket, and the frost tolerant shrublands of the Nama-Karoo.

show abstract

“…Recent studies suggest that recurrent frosts can reinforce boundaries between tropical savannas and forests in Brazil (Hoffmann et al, ) or between savannas and shrublands in South Africa (Muller, O'Connor, & Henschel, ). Extreme freezing events could be thus important for maintaining or reducing tropical and subtropical ecosystems sharp borders and range limits by inducing tree mortality in species with low frost resistance (e.g., Whitecross, Archibald, & Witkowski, ). Our limited knowledge about the effects of frost disturbance on tropical forests restricts our ability to accurately identify frost‐prone areas, particularly at the landscape scale where forest management planning usually takes place.…”

Section: Introductionmentioning

confidence: 99%

Understanding and predicting frost‐induced tropical tree mortality patterns

Bojórquez

Álvarez‐Yépiz

Búrquez

et al. 2019

Global Change Biology

View full text Add to dashboard Cite

Extreme climatic and weather events are increasing in frequency and intensity across the world causing episodes of widespread tree mortality in many forested ecosystems. However, we have a limited understanding about which local factors influence tree mortality patterns, restricting our ability to predict tree mortality, especially within topographically complex tropical landscapes with a matrix of mature and secondary forests. We investigated the effects of two major local factors, topography and forest successional type, on climate‐induced tropical tree mortality patterns using an observational and modeling approach. The northernmost Neotropical dry forest endured an unprecedented episode of frost‐induced tree mortality after the historic February 2011 cold wave hit northwestern Mexico. In a moderately hilly landscape covering mature and secondary tropical dry forests, we surveyed 454 sites for the presence or absence of frost‐induced tree mortality. In addition, across forty‐eight 1 ha plots equally split into the two forest types, we examined 6,981 woody plants to estimate a frost‐disturbance severity metric using the density of frost‐killed trees. Elevation is the main factor modulating frost effects regardless of forest type. Higher occurrence probabilities of frost‐induced tree mortality at lowland forests can be explained by the strong influence of elevation on temperature distribution since heavier cold air masses move downhill during advective frosts. Holding elevation constant, the probability of frost‐induced tree mortality in mature forests was twice that of secondary forests but severity showed the opposite pattern, suggesting a cautious use of occurrence probabilities of tree mortality to infer severity of climate‐driven disturbances. Extreme frost events, in addition to altering forest successional pathways and ecosystem services, likely maintain and could ultimately shift latitudinal and altitudinal range margins of Neotropical dry forests.

show abstract

Do freeze events create a demographic bottleneck for Colophospermum mopane?

Cited by 35 publications

References 27 publications

Climate refugees going underground – a response to Maurin et al. (2014)

Climate refugees going underground – a response to Maurin et al. (2014)

Frost, Portulacaria afra Jacq., and the boundary between the Albany Subtropical Thicket and Nama-Karoo biomes

Understanding and predicting frost‐induced tropical tree mortality patterns

Contact Info

Product

Resources

About