Threats to the Conservation of Southwestern Australian Proteaceae

Lamont, Byron B.; Wills, Robin; Witkowski, E.T.F.

doi:10.17660/actahortic.1995.387.1

Cited by 9 publications

(5 citation statements)

References 11 publications

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“…Previous studies have reported that few or no banksias are killed due to prescribed burning (Baird 1977;Lamont 1985;Enright and Lamont 1989;Hobbs and Atkins 1990). Prescribed burning is more likely to remove a short understory rather than the midstory or canopy strata (Baird 1977;Lamont et al 1995;Hodgkinson 2002;Sitters et al 2015). Removing the understory can temporarily reduce resource competition (Gill 1975), which may enhance growth Table 3 The numbers of B. attenuata and B. menzeseii adult trees and cones per hectare, closed follicles per cone, and estimated grams of seed per hectare and carrying capacity for Carnaby's cockatoo compared among banksia woodland sites located 30 to 50 km north of Perth, Western Australia, from 2017 through 2019.…”

Section: Discussionmentioning

confidence: 99%

“…Prescribed burning represents a useful tool to minimize disturbance caused by unplanned bushfire, particularly when high-intensity bushfires are typically stand-replacing events. To conserve viable populations of Carnaby's cockatoo, it is necessary to maintain or increase areas that contain productive B. attenuata and B. menziesii adults, particularly as the population size of banksia stands may affect seed set (Lamont et al 1995). Prescribed burning produces a mosaic of lower intensities, including unburned patches, compared to a more uniform high intensity typical of bushfires in banksia woodland (Wilson et al 2010).…”

Section: Discussionmentioning

confidence: 99%

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Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby’s cockatoo

Densmore¹,

Clingan²

2019

fire ecol

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Background: Prescribed burning is used to reduce fire hazard in highly flammable vegetation types, including Banksia L.f. woodland that occurs on the Swan Coastal Plain (SCP), Western Australia, Australia. The 2016 census recorded well over 1.9 million people living on the SCP, which also encompasses Perth, the fourth largest city in Australia. Banksia woodland is prone to frequent ignitions that can cause extensive bushfires that consume canopystored banksia seeds, a critical food resource for an endangered bird, the Carnaby's cockatoo (Calyptorynchus latirostris, Carnaby 1948). The time needed for banksias to reach maturity and maximum seed production is several years longer than the typical interval between prescribed burns. We compared prescribed burns to bushfires and unburned sites at three locations in banksia woodland to determine whether low-intensity prescribed burns affect the number of adult banksias and their seed production. Study sites were matched to the same vegetation complex, fire regime, and timesince-fire to isolate fire intensity as a variable. Results: Headfire rates of spread and differenced normalized burn ratios indicated that prescribed burning was generally of a much lower intensity than bushfire. The percentage survival of adult banksias and their production of cones and follicles (seeds) did not decrease during the first three years following a prescribed burn. However, survival and seed production were significantly diminished followed high-intensity bushfire. Thus, carrying capacity for Carnaby's cockatoo was unchanged by prescribed burning but decreased markedly following bushfire in banksia woodland. Conclusions: These results suggest that prescribed burning is markedly different from bushfire when considering appropriate fire intervals to conserve canopy habitats in fire-resilient vegetation communities. Therefore, low-intensity prescribed burning represents a viable management tool to reduce the frequency and extent of bushfire impacts on banksia woodland and Carnaby's cockatoo.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby’s cockatoo

Densmore¹,

Clingan²

2019

fire ecol

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“…There have been numerous examples of parasites and diseases posing major threats to populations of endangered species ( MacCallum & Dobson 1995). In south‐western Australia, the root fungus Phytophthora cinnamomi is a major conservation problem ( Lamont et al 1995 ). Bacterial wilts are often not particularly host‐specific and could be carried by woody plants and spread through the soil or via pollinators ( Billing 1987).…”

Section: Discussionmentioning

confidence: 99%

Conservation biology of the succulent shrub, Euphorbia barnardii, a serpentine endemic of the Northern Province, South Africa

Knowles¹,

Witkowski²

2000

Austral Ecology

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Euphorbia barnardii White, Dyer & Sloane is a relatively small, succulent shrub found in the Northern Province of South Africa. In 1994 it was listed as endangered by the Transvaal Threatened Plants Programme, because only three populations, totalling 1150 plants, were found. However, our study found five populations totalling 10 783 plants (9503 were reproductive). One population, found 50 km from the others, in the Bewaarkloof district, differs in terms of habitat type and morphology and may therefore be a different taxon. The other populations occur in Sekhukhuneland. Soil analyses showed that E. barnardii is restricted to ultramafic (serpentine) substrates. A sample of 2015 plants was examined in 1995 for size, stage, new growth, dead branches, reproduction (indices of vigour), damage and disease. Analysis of the results of 10 years’ demographic monitoring (1985–1995) on two of the Sekhukhuneland populations showed that one population, which was vigorous in 1995, showed little change in population size and structure, while the other, which had low vigour in 1995, showed a precipitous decline to local extinction in the monitoring plot. Aerial photographs taken in 1957 (1963 for Bewaarkloof) and 1986 showed large increases in human population density within 1.5 km of the E. barnardii populations except at Bewaarkloof, where it decreased. An increase in human habitation is associated with an increase in livestock (mostly cattle and goats) which trample plants. Trampling damages the terminal segments, which may lead to lowered reproductive output and increase susceptibility to opportunistic bacterial wilt pathogens. Bacterial wilts were prevalent on all populations but were particularly high at Bewaarkloof and on the population that showed a steep decline in numbers. Disease incidence was associated with the level of plant damage. The impact on plants further up the slopes and on the crest of hills (quite far from human settlements) was to a far lesser degree but further increases in human population density could change this situation. While this study has shown that the population size of E. barnardii is much greater than previously thought, the species is still threatened by several different processes and should be listed as ‘Vulnerable (A1a + c, B1, B2b + e, C1, D2)’ according to World Conservation Union categories.

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“…Resolving the taxonomy of these complexes is essential to ensuring adequate documentation of diversity and effective direction of conservation efforts. Many members of Proteaceae have proven more susceptible than other plant groups to threatening factors in the SWAFR, including progressively hotter and drier climate, root‐rot pathogens and other diseases, and the continuing degradation of remnant vegetation through weed infestation and ongoing land clearing (Lamont & al., 1995; Monks & al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Revised taxonomy for two species complexes of Western Australian Isopogon (Proteaceae) using RADseq

Anderson,

Binks,

Byrne

et al. 2024

TAXON

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The Australian genus Isopogon (Proteaceae) consists of approximately 39 species, most of which occur in southwestern Australia, a region of considerable endemism and biodiversity. Unresolved taxonomic issues exist for two species complexes (nine suspected taxa) allied to I. spathulatus and I. polycephalus. There is uncertainty in how to delimit species in these two complexes due to unclear or overlapping morphological characters, although recognition of four phrase‐named taxa provide starting hypotheses for potential new taxa. We used a genomic approach (ddRAD) to generate SNPs for 146 samples from 32 populations across the two complexes to evaluate the genomic distinction of taxa and delimit species. We used an optimised ipyrad assembly of the sequenced libraries, followed by custom filtering of samples and SNPs for ordination, genetic structure, distance and concatenation and coalescent phylogenetic analyses. Population genetic and phylogenetic analyses consistently supported three geographically overlapping yet genomically distinct groups, two of which showed additional genomic divergence consistent with multiple distinct species. Existing morphological hypotheses were congruent with genomic groupings in some cases but discordant in others, where genomic admixture suggested existing taxa were conspecific. Evaluating morphological characters, geographic distribution and genomic distinction, we recognise five species and three subspecies from nine original taxa. We provide a key to species in the complexes and related taxa, updated descriptions for existing taxa, and describe two new species, I. elatus sp. nov. and I. pallidus sp. nov., and two new subspecies, I. spathulatus subsp. obovatus stat. nov. and I. spathulatus subsp. elongatus subsp. nov.

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Threats to the Conservation of Southwestern Australian Proteaceae

Cited by 9 publications

References 11 publications

Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby’s cockatoo

Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby’s cockatoo

Conservation biology of the succulent shrub, Euphorbia barnardii, a serpentine endemic of the Northern Province, South Africa

Revised taxonomy for two species complexes of Western Australian Isopogon (Proteaceae) using RADseq

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