Species Richness of Sclerophyll (Heathy) Plant Communities in Australia ̵2 the Influence of Overstorey Cover

1989 ◽  
Vol 37 (4) ◽  
pp. 337 ◽  
Author(s):  
RL Specht ◽  
A Specht

The species richness (number of vascular-plant species per unit area) of sclerophyll (heathy) plant communities is examined from south-east Queensland to south-west Western Australia. The species richness of communities of heathy open forest, heathy open scrub, dry heathland and wet heathland is consist- ently similar throughout southern Australia and decreases from dry heathland (on laterite, coastal and inland localities) to heathy open forest, heathy open scrub and wet heathland. Investigation of related microcommunities at Cooloola, Stradbroke Island, Ku-ring-gai Chase and Wilsons Promontory indicates that species richness decreases linearly as overstorey cover increases. In post-fire succession on Stradbroke Island heathy woodland and Dark Island heathland, species richness declines linearly as overstorey cover increases during the regeneration of the community. The appli- cation of limiting fertiliser to Stradbroke Island heathy woodland and Dark Island heathland increases the rate of development of overstorey cover, with a simultaneous decrease in species richness. Species richness of the understorey strata of plant communities appears to be inversely related to the rate of development of foliage projective cover in the overstorey. If an environmental or biotic factor inhibits or retards the development of overstorey cover, the understorey increases in species richness. Conversely, if any environmental or biotic factor accelerates the development of overstorey cover, the understorey species show a reduction in species richness.

Author(s):  
Marju Prass ◽  
Satu Ramula ◽  
Miia Jauni ◽  
Heikki Setälä ◽  
D. Johan Kotze

AbstractThe ecological impacts of invasive species may change or accumulate with time since local invasion, potentially inducing further changes in communities and the abiotic environment. Yet, time since invasion is rarely considered when investigating the ecological impacts of invasive non-native species. To examine the effect of time since invasion on the ecological impacts of Lupinus polyphyllus, a perennial nitrogen-fixing herb, we surveyed vascular plant communities in the presence and absence of L. polyphyllus in young, intermediate, and old semi-natural grassland sites (ca. 5, 10, 15 years representing both time since lupine invasion and plant community age). We analyzed vascular plant community composition, vascular plant species richness, and the cover of various ecological plant groups and L. polyphyllus. In contrast to our hypotheses, we found no change in the mean cover of L. polyphyllus (about 35%) with time since local invasion, and an ordination did not suggest marked changes in plant community composition. L. polyphyllus was associated with lower species richness in invaded plant communities but this effect did not change with time since invasion. Invaded plant communities were also associated with lower occurrence of generalist, oligotrophic (low-nutrient-adapted) and copiotrophic (nutrient-demanding) species but no temporal dynamics were detected. We conclude that even the intermediate cover of L. polyphyllus can reduce plant species richness, but the ecological impact caused by this invader might not dramatically change or accumulate with time since invasion.


Check List ◽  
2009 ◽  
Vol 5 (1) ◽  
pp. 035 ◽  
Author(s):  
Ruy José Válka Alves ◽  
Jiří Kolbek

The campos rupestres form a mosaic of rocky savannas concentrated mainly along the Espinhaço chain, on the Brazilian shield. Though the Serra de São José lies over 100 km to the south of the Espinhaço chain, the campo rupestre flora of this small range harbors several endemic plant taxa. The provided checklist is the result of two decades of floristic research complemented with data from herbaria and literature. The flora is compared with the results of several other pertinent surveys. A total of 1,144 vascular plant species, representing 50.3 species/km2, were documented to date in the São José range, representing a species-richness per unit area over five times greater than other known campo rupestre floras. The most species-rich families were the Asteraceae (126 species), Orchidaceae (106), Melastomataceae (63), Leguminosae (60), Cyperaceae (45), Poaceae (41), Rubiaceae (37), Myrtaceae (28), Bromeliaceae (27), Eriocaulaceae (23), Lamiaceae (23), and Malpighiaceae (22).


2017 ◽  
Vol 105 (5) ◽  
pp. 1199-1209 ◽  
Author(s):  
Marion Boutin ◽  
Emmanuel Corcket ◽  
Didier Alard ◽  
Luis Villar ◽  
Juan-José Jiménez ◽  
...  

2007 ◽  
Vol 55 (3) ◽  
pp. 225 ◽  
Author(s):  
B. L. Shearer ◽  
C. E. Crane ◽  
S. Barrett ◽  
A. Cochrane

The invasive soilborne plant pathogen Phytophthora cinnamomi Rands is a major threatening process in the South-west Botanical Province of Western Australia, an internationally recognised biodiversity hotspot. Comparatively recent introduction of P. cinnamomi into native plant communities of the South-west Botanical Province of Western Australia since the early 1900s has caused great irreversible damage and altered successional change to a wide range of unique, diverse and mainly susceptible plant communities. The cost of P. cinnamomi infestation to community values is illustrated by examination of direct (mortality curves, changes in vegetation cover) and indirect impacts on biodiversity and ecosystem dynamics, the proportion of Threatened Ecological Communities infested, Declared Rare Flora either directly or indirectly threatened by infestation and estimates of the proportion of the native flora of the South-west Botanical Province susceptible to the pathogen. While direct impacts of P. cinnamomi have been poorly documented in the South-west Botanical Province, even less attention has been given to indirect impact where destruction of the habitat by the pathogen affects taxa not directly affected by infection. Current poor understanding and quantification of indirect impacts of P. cinnamomi through habitat destruction results in an underestimation of the true impact of the pathogen on the flora of the South-west Botanical Province. Considerable variation of susceptibility to P. cinnamomi among and within families of threatened flora and responses of taxa within the genus Lambertia show how classification within family and genus are poor predictors of species susceptibility. Within apparently susceptible plant species, individuals are resistant to P. cinnamomi infection. Intra-specific variation in susceptibility can be utilised in the long-term management of threatened flora populations and needs to be a high research priority. Current control strategies for conservation of flora threatened by P. cinnamomi integrate hygiene and ex situ conservation with disease control using fungicide. Application of the fungicide phosphite has proven effective in slowing progress of P. cinnamomi in infested, threatened communities. However, variation in plant species responses to phosphite application is a major factor influencing effective control of P. cinnamomi in native communities. A greater understanding of the mechanisms of action of phosphite in plant species showing different responses to the fungicide may provide options for prescription modification to increase phosphite effectiveness in a range of plant species. The range of responses to P. cinnamomi infection and phosphite application described for Lambertia taxa suggests that the genus would make an ideal model system to elucidate the mechanisms of resistance to P. cinnamomi and the effectiveness of phosphite against the pathogen.


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