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Plantations, and associated invasions, of exotic Pinus trees occur extensively in the southern hemisphere, threatening the persistence of biodiverse Mediterranean‐climate vegetation. Large‐scale decommissioning of such plantations in the eastern Cape Floristic Region (South Africa) enabled a wide‐ranging study showing successful passive restoration of fynbos vegetation after afforestation. Using a paired study design, we compared the diversity, and floristic and growth‐form composition of post‐fire recovering fynbos in former plantations with that in recently burnt neighboring fynbos in a natural state within the Garden Route National Park. The fynbos of the study area showed good autogenic recovery after several decades of pine afforestation and a fire subsequent to the clearcutting of these trees. On average, native plant abundance and species richness (particularly of shrubs) were significantly lower, and non‐native plant species richness significantly higher, in former plantation areas than in natural fynbos, but these differences were small. Species diversity (Shannon–Wiener index) did not differ significantly between the two vegetation states. The former plantations harbored 91% of the number of native species that the natural fynbos had, while the similarity of the two floras was 65%. Non‐metric multidimensional scaling ordination and multivariate generalized linear models accordingly showed no clear distinction in community composition between the two vegetation states. We concluded that the restoration potential of the montane grassy fynbos in the study area is superior to that previously documented in montane proteoid fynbos, and that fire and invasive alien plant control after clearcutting of the plantations is essential to promote fynbos restoration. [ABSTRACT FROM AUTHOR]

The expansion of subtropical thicket vegetation at the expense of more species-rich, fire-prone fynbos, potentially due to lower frequency and severity of fire and browsing, is a concern in many coastal dune landscapes of the Cape Floristic Region (CFR) where these two vegetation types co-occur. We were interested in the effects of severe fire or browsing treatments (causing complete loss of aboveground biomass) on the vigour of post-fire resprouts of dune thicket shrubs. Cape St Francis, CFR, South Africa. We used an in situ experimental approach to compare the effects of simulated fire and browsing by herbivores on mortality, resprouting vigour and resprouting rate of 10 canopy-forming dune thicket shrub species from different architectural guilds, 5 years after a previous severe wildfire. Survival was significantly lower after fire (85%) than after browsing (95%), and was significantly positively related to pre-treatment shrub size. All measures of resprouting vigour were significantly lower after fire than after browsing, and were significantly positively related to pre-treatment size. Resprouting rate was significantly lower after fire than after browsing, and was significantly positively affected by pre-treatment size. Survival and measures of resprouting vigour were generally decoupled from architectural guild and species identity. Dune thicket shrubs showed high survival after both fire and browsing treatments, suggesting that these species are resilient to frequent complete loss of above-ground biomass. Our results suggest that short interval fires (5–15 years) of high severity will merely maintain the co-occurrence of dune fynbos and thicket vegetation by setting back thicket growth rather than causing large-scale mortality of thicket shrubs. [ABSTRACT FROM AUTHOR]

In Mediterranean-Climate Ecosystems (MCEs), Holocene coastal dunes comprise small, fragmented and dynamic features which have nutritionally imbalanced and excessively drained, droughty, sandy soils. These characteristics, along with summer drought and salt-laden winds, pose many challenges for plant colonization and persistence. Consequently, MCE dune floras are likely to be distinctive with a high proportion of habitat specialists and strong convergence in growth form mixes. Very little research has compared the species traits of dune floras within and across MCEs. This paper contributes to filling that gap. Here, we analyze the taxonomic, biological and geographical traits for all 402 species in a flora from a dune landscape (Cape St Francis) in the southeastern Cape Floristic Region (CFR) and compare patterns with the trait profiles of other dune floras at a regional (CFR) and global (MCE) scale. Within the CFR, the southeastern (all-year-rainfall) flora at Cape St Francis had a similar trait profile to western (winter-rainfall) dune floras, except for having a lower representation of species belonging to CFR-endemic clades, and higher number of species associated with tropical lineages. The St Francis flora, in common with other CFR and MCE floras, was dominated by members of the Asteraceae, Fabaceae and Poaceae. Some 40% of the St Francis flora was endemic to the CFR, typical of the high rate of MCE-level endemism elsewhere in the CFR, and in other MCEs. About 30% of the flora was confined to calcareous sand, a value typical for many other MCE sites. The St Francis flora, as well as other CFR dune floras, differs from those of other MCEs by having many species associated with shrubby lineages, and by the relatively high incidence of species associated with tropical lineages. The growth form profile of the St Francis and other CFR floras shows strongest similarity with that of Australian MCE dunes in that in both regions, evergreen hemicryptophytes and shrubs share dominance, and annuals are floristically and ecologically subordinate. The least similar of MCEs to the St Francis trait profile is the Mediterranean Basin where annuals are the most frequent growth form while shrubs are subordinate. California and Chile dune floras appear to occupy an intermediate position, in terms of growth form mix, between the Cape and Australia on the one hand, where dune floras have retained features typical of nutrient-poor soils, and the Mediterranean Basin, where dwarf, deciduous shrubs and annuals dominate the life form spectrum. All MCE dunes are threatened by alien plants, infrastructure development, tourism demands and rising sea levels. The high incidence of species of conservation concern in CFR dune floras underestimates the exponentially increasing threats to their habitats, which are already historically at a much-reduced extent. All remaining coastal dune habitat in the CFR, and probably in other MCEs, should be conserved in their entirety. [ABSTRACT FROM AUTHOR]

Southern Africa's Greater Cape Floristic Region (GCFR) – a hotspot of biological diversity and palaeo-anthropological evidence for modern human evolution – is a climatically complex region where broad climatic gradients influence the relative importance of plant photosynthetic types in local vegetation. This mix of photosynthetic pathways imprint an isotopic signature on palaeo-records, thereby allowing for the reconstruction of historical climate and vegetation. Here, we use vegetation plot data, coupled with the photosynthetic-type affinities of plant genera, to relate their relative cover to bioclimatic drivers and use these to create spatial distribution models of C 3 and C 4 grasses and CAM shrubs across the contemporary GCFR. We then use palaeodistribution modelling, drawing on downscaled climate models for the Last Glacial Maximum (LGM), to hindcast the LGM distributions of photosynthetic types for the GCFR and its then-exposed offshore areas. In addition, we construct a model to account for the effect of lower atmospheric CO 2 concentration ([CO 2 ]) during the LGM on the competitive interactions between C 3 and C 4 grasses and use this model to hindcast relative C 4 -grass cover across the glacial-era GCFR. Our palaeodistribution models suggest that, even though there were some reductions in CAM cover and shifts in C 3 -/C 4 -dominated grass layers between the LGM and Holocene, these were mostly localised, with changes at the regional scale being relatively muted. For C 3 /C 4 grasses, distributional shifts were even more subtle once sub-ambient glacial [CO 2 ] was accounted for. Our hindcasts of glacial, [CO 2 ]-adjusted grass cover show agreements and inconsistencies with various sedimentary and herbivore-diet records in the palaeo-archive: both lines of evidence suggest the dominance of C 3 species in the strongly winter-rainfall western GCFR; in the eastern GCFR, with muted rainfall seasonality, hindcasts of relative C 3 :C 4 cover and δ13C signals from palaeo-records vary, with greater disparities between them. The lack of significant upheavals in the distribution of photosynthetic types suggests that the GCFR presented a relatively stable and dependable resourcescape for hunter-gatherer populations through the glacial–interglacial cycle of the LGM–Holocene transition. Our maps of relative C 3 -/C 4 -grass and CAM-shrub cover provide a reasonable surrogate for relative biomass of different photosynthetic types in local vegetation at a landscape scale and depict an independent estimate of carbon isoscapes across the GCFR – under both an interglacial (Holocene) and glacial (terminal Pleistocene) climate – against which palaeo-records can be assessed. • Spatial models of relative cover of CAM shrubs and C 3 /C 4 grasses under current and LGM climates • Spatial model of relative C 4 -grass cover under LGM climate and atmospheric CO 2 concentration ([CO 2 ]) • Muted changes in distribution of photosynthetic types through LGM–Holocene transition • Distributional shifts for C 4 grasses more subtle when sub-ambient glacial [CO 2 ] is accounted for • Maps of CAM-shrub and C 3 -/C 4 -grass cover can be used to assess palaeo-records of carbon isoscapes [ABSTRACT FROM AUTHOR]