Banksia Woodland Research Articles

Recharge beneath a Banksia woodland and a Pinus pinaster plantation on coastal deep sands in south Western Australia

Recharge was estimated using three methods during a three-year period (1985–1988) in a Banksia woodland and a dense Pinus pinaster plantation growing on deep sandy soils in the northern Swan Coastal Plain. The methods of estimating recharge were water balance, chloride balance and ground-water-table rise. Substantially less rainwater infiltrated into the shallow groundwater (about 6 m deep) beneath the pine plantation compared with the Banksia woodland. The relative difference in recharge between the two vegetation types increased during years of below average rainfall. When averaged over the three methods of recharge estimation during the three years, recharge beneath the pine plantation was 114 mm (equivalent to 15% of annual rainfall), and beneath Banksia woodland was 173 mm (equivalent to 22% of annual rainfall). Reduced recharge under pines and the merits of the methods of recharge estimation are discussed.

Fire-Related Dynamics of a Banksia Woodland in South-Western Western Australia

We studied the post-fire vegetation development of a low open woodland dominated by Banksia attenuata and B. menziesii near Perth, Western Australia. Two similar stands burned in autumn and spring displayed different regeneration patterns, with seedling regeneration occurring only in the autumn burn area. Vegetative regrowth was more rapid and post-fire species numbers were higher in the spring burn area. Introduced annuals increased significantly in the autumn fire area. Longer-term vegetation development was studied in a series of stands ranging in age since last fire from 1 to >44 years. Species richness was greatest in the 5-year-old stand, and many shrub species were most abundant 2-5 years after fire. Non-native annuals were found only in stands less than 5 years old since last fire. Dominance by the shrub Eremaea pauciflora increased with stand age, although shrub structure and total biomass did not vary greatly except in the oldest stand studied. The proportion of total shrub biomass accounted for by leaves declined with stand age. Both the two major Banksia species had mixed size structures with seedlings present in all stands, indicating that neither is dependent on fire for recruitment. The results indicate that while autumn burns promote seedling regeneration they may also increase invasion by non-natives, and spring burning may be preferable in these Banksia woodlands. Burning rotations longer than those required for fuel reduction purposes are necessary to maximise conservation values.

Life-History of the Eastern Pygmy-Possum, Cercartetus-Nanus (Burramyidae, Marsupialia), in South-Eastern Australia

Populations of Cercartetus nanus were investigated in three areas of Victoria: two areas of Banksia woodland at Wilsons Promontory National Park and an area of mixed eucalypt forest with an under- storey of B. spinulosa at Nar Nar Goon North, east of Melbourne. Most births occurred between November and March, but in areas where the dominant Banksia sp. flowered in winter they took place year-round. Most females produced two litters in a year, but some produced three. Males were reproductively active throughout the year. Litter sizes ranged from two to six, with a modal size of four. Pouch life lasted 30 days and weaning occurred at 65 days. Growth was rapid, young became independent immediately after weaning, and matured as early as 4.5-5.0 months old. Maximum longevity in the field was at least 4 years.

The seasonal abundance and foraging behaviour of honeyeaters and their potential role in the pollination ofBanksia menziesii

AbstractSeasonal changes in the abundances of five species of honey‐eaters were assessed in relation to the flowering phenology of Banksia menziesii in banksia woodland near Perth, Western Australia. The total number of honeyeaters was significantly correlated to the number of inflorescences ofB. menziesii. New Holland Honeyeaters. Brown Honeyeaters and Western Spinebills were present throughout the year, whereas the larger honeyeaters (Red and Little Wattlebirds) were observed when B. menziesii was flowering.The foraging behaviours of the Little Wattlebirds, New Holland Honeyeaters, Brown Honeyeaters and Western Spinebills were similar and all were likely to effect pollination of B. menziesii florets. Differences in their foraging position at an inflorescence, number and direction of foraging probes, and the time spent at an inflorescence were minimal. Western Spinebills used inflorescences lower in the tree crown than the other species. Movements to inflorescences on different plants were inversely related to honeyeater size. Smaller honeyeaters were frequently chased from inflorescences by the larger species, increasing the proportion of distant foraging movements made by the smaller species. Also these interrupted visits were of shorter duration than uninterrupted visits. Visitation by smaller species, especially the Brown Honeyeater, may result in more cross pollinations although the effect on the reproductive success of B, menziesii is unknown.

Evaporation from Banksia woodland on a groundwater mound

Annual evaporation from a site within a Banksia woodland on a groundwater mound near Perth, Western Australia, was estimated from measurements of daily evaporation by ventilated chambers on fourteen occasions during a 12-month period. The total evaporation for this period was estimated to be 666 mm (77% of annual rainfall). About two-thirds of the total evaporation came from the ground flora, one-fifth from Banksia trees, and the remainder from the tall shrub Adenanthos cygnorum. Depth to water table, which ranged from 4 to 12 m over the site, had little effect on total evaporation. This work suggests that regular reduction in ground flora foliage, for example, by controlled burning could increase recharge.

Floret Opening in Banksia menziesii R.Br.; The Importance of Nectarivorous Birds

The rates and causes of floret opening in Banksia menziesii were examined in banksia woodland near Perth, Western Australia. On average, 40-60 florets opened per 24 h but this rate was highly variable over the flowering of individual inflorescences. The ages of inflorescences did not greatly influence the rate of floret opening, although fewer florets opened towards the end of flowering. Floret opening occurred predominantly during the day. The numbers of florets opening were similar in wet and dry weather conditions. Florets opened mainly in response to foraging by nectarivorous birds (Meliphagidae) but not honey bees. This would result in more effective pollen transfer to potential avian vectors which may enhance reproductive success.

Thesis abstracts

Bioturbation, rainwash and texture contrast soils: An evaluation of transporting processes on soil genesis in the Sydney Basin G. S. HumphreysSome aspects of the role of bioturbation in soil formation in south‐eastern Australia P. B. MitchellPlant water relations and community water use in a Banksia woodland near Perth, Western Australia Jonathan DoddThe pre‐mining assessment of a coal mining lease north of Esperance, Western Australia Paul G. van der Moezel

Seasonal changes in a honeyeater assemblage inBanksiawoodland near Perth, Western Australia

Abstract Honeyeaters were the most numerous birds in banksia woodland near Perth, Western Australia, throughout the year. Numbers were greatest in a Banksia littoralis swamp, but only during those few months when it contained large amounts of nectar. In the surrounding woodland, numbers were lower but fairly constant during the year. This reflects the smaller amounts of nectar produced throughout the year, by the overlapping flowering patterns of several Banksia and Adenanthos species. Large and medium-sized honeyeaters (wattlebirds and New Holland Honeyeaters) and flocking silvereyes dominated the swamp when it flowered. In contrast, small honeyeaters (spinebills and Brown Honeyeaters), many of whom were highly territorial residents, comprised the majority of the woodland assemblage throughout the year. These observations support a model based upon aggressive defence of rich nectar sources by the larger honeyeater species, and more efficient exploitation of dispersed flowers by smaller honeyeaters.

The Invertebrate Diets of Small Birds in Banksia Woodland Near Perth, W.a., During Winter.

Honeyeaters were the most abundant birds in Banksia woodland in winter, and all species ate insects. Short-billed honeyeaters and non-nectarivores took mostly beetles, ants and bugs by gleaning, whereas long-billed honeyeaters fed more on nectar and caught mostly flies and wasps by hawking. Short-billed species segregated in their foraging heights, prey types and sizes. Long-billed species, however, overlapped considerably in these respects and all took similar small insects whose capture they may have had to subsidize with energy from nectar.

Flowering phenology, seed set and bird pollination of five Western Australian Banksia species

AbstractFlowering phenology and seed set characteristics of five species of Banksia were studied in relation to the nectarivorous birds which feed at their inflorescences. Within the Banksia woodland at the study site near Perth, the flowering seasons of the Banksia species were sequential and only slightly overlapping, providing a year‐round nectar source. Although honeyeaters visited alt five species, seed set was very low in each case. Caging experiments indicated that, in B. attenuata at least, alternative pollinators may play a more important role in pollination than do nectar‐feeding birds. It is suggested that non‐avian pollinators, predatory insects, and characteristics of the breeding system may also have been important in the evolution of the observed flowering phenology and patterns of seed set.

Reproduction in the Herpetofaunal Community of a Banksia Woodland Near Perth, W.a.

Twelve species of lizards (Agamidae, Scincidae, Pygopodidae) and three species of frogs (Leptodac- tylidae) comprise the herpetofaunal community of a Banksia woodland under a mediterranean-type climate in Western Australia. The reptiles bred in September-November and laid eggs in early summer. The requirement of surface water for tadpole development for two of the frog species restricted their breeding time to winter and necessitated their migration from the study area, where no water was avail- able. The third species of frog, Myobatrachus gouldii, lacks an aquatic stage. Its reproductive pattern coincided with neither that of the reptiles nor the other frogs. Collections of most species in the com- munity were not equally divided between sexes. For reptiles, this possibly was owing to differential trapping of the sexes. The very high frequency of capture of female frogs, other than those of M. gouldii, was probably related to differential dispersal of the sexes from breeding areas. The distribution of the percentage frequency of snout-vent lengths for six species of lizards suggests that individuals did not breed until their second year.

A census of a community of small terrestrial vertebrates

A small vertebrate community of eighteen terrestrial species was revealed by removal trapping in 1 ha of Western Australian Banksia woodland in autumn. Nine of these species were lizards, three were mammals, three were snakes and three were frogs. The use of pitfall and mammal traps on an 8 × 8 m grid was shown to be sufficient to census the majority of terrestrial species in the study site. A biomass of 2063 g/ha of terrestrial species was estimated from trapping records. Frogs (three species) had the greatest biomass (41% of total), but the introduced mouse Musmusculus contributed the greatest biomass (36%) of any single specie.