Phenologies and Litter Fall of Two Mangrove Trees, Sonneratia alba Sm. And S. caseolaris (L.) Engl., And Their Putative Hybrid, S. × Gulngai N.C. Duke

1988 ◽  
Vol 36 (4) ◽  
pp. 473 ◽  
Author(s):  
NC Duke

Litter fall studies were used to assess phenologies and productivity of Sonneratia alba, S. caseolaris and their putative hybrid, S. × Gulngai, in north-eastern Australia. Annual total litter falls (mean ± s.d.) were 2.5 × 0.5, 2.6 × 1.4 and 3.2 g dry weight m-2 day-1, respectively. Litter was partitioned into leaves (47, 61 and 50%), wood (12, 14 and 19%) and reproductive parts (41, 25 and 31%). In addition, monthly reproductive schedules were produced for each taxon. Differences between taxa were pronounced. For S. alba, flowering peaked in December and fruiting in February. For S. caseolaris, flowering peaked in late February and fruiting in June and July. S. × Gulngai was characterised by an apparent combination of events described for the two putative parental forms. This observation, along with a low (a%) fruiting success, provides further support for the hybrid status of this taxon.

1981 ◽  
Vol 29 (5) ◽  
pp. 547 ◽  
Author(s):  
NC Duke ◽  
JS Bunt ◽  
WT Williams

Annual totals of the components of litter fall (leaves, reproductive parts, stipules, wood and residual debris) are presented for Rhizophora apiculata, R. lamarckii and R. stylosa as well as for Sonneratia alba, Avicennia sp., Ceriops tagal, Bruguiera gymnorrhiza and B. parviflora from a large number of sites at Hinchinbrook Island (lat. 18°15'S.; long. 146°15'E.). Annual total litter fall among all species ranged from 3.8 to 19.6 Mg ha-1. The mean value among the Rhizophora spp., the most extensively sampled was 9.6 Mg ha-1 yr-1. Leaves, generally, made up the most important component of all litter materials. The results are compared with records in the literature for tidal as well as non-tidal forests elsewhere in the tropics.


1981 ◽  
Vol 29 (5) ◽  
pp. 555 ◽  
Author(s):  
WT Williams ◽  
JS Bunt ◽  
NC Duke

Fourier analysis was used to demonstrate distinctive seasonal patterns of leaf litter fall in the mangrove species Rhizophora apiculata, R. stylosa and R. lamarckii. Similar treatment of data for stipule fall was not successful, indicating that this process may be controlled by random events. The fall of leaves and reproductive parts appears to be correlated with climatic factors, notably rainfall, in a fashion that varies with species. Seasonal trends without Fourier analysis are described for Sonneratia alba, Bruguiera gymnorrhiza, B. parviflora, Avicennia sp. and Ceriops tagal in terms of leaves and reproductive parts, and for leaves only in Excoecaria agallocha, Xylocarpus granatum, Heritiera littoralis, Lumnitzera racemosa and L. littorea.


1984 ◽  
Vol 32 (1) ◽  
pp. 87 ◽  
Author(s):  
NC Duke ◽  
JS Bunt ◽  
WT Williams

The mangrove forests of north-eastern Australia are both species-rich and well developed but there is very little information available on their vegetative growth or flowering and fruiting behaviour. This account attempts to rectify this situation by presenting the results of at least 4 years of field studies and observations. Previous reports recorded no less than 35 mangrove species occumng along the north-eastern coast and observations of the flowering and fruiting status of all these species were made. The results are supported by some litter fall studies and overall they reflect the diversity of mangrove species by displaying a range of peak activity months. However, there are some common trends and most species flower mainly during the dry hot summer (September-December) prior to the rainy season when they drop their propaguies during the morniks of peak rainfall (around February). Detailed studies of litter fall were camed out in Missionary Bay, Hinchinbrook Island (18° 16̸2S.,146° 13̸2E.), and care was taken to record components of floral development and vegetative growth. The results for five species (Rhizophora apiculata, R. stylosa, R. × lamarckii, Bruguiera gymnorhiza and Ceriops tagal var. tagal) include estimates of mean leaf longevity and also suggest that the floral and vegetative cycles are coordinated.


1982 ◽  
Vol 12 (1) ◽  
pp. 40-51 ◽  
Author(s):  
Nancy L. Ostman ◽  
George T. Weaver

Retranslocation from leaves was investigated as a means of retaining nutrients in stands of Quercusprinus L. on two sites in southern Illinois, where wind rapidly moves litter downslope. Foliage samples were collected from late summer until leaf fall to describe the trends of leaf dry weight and nutrient concentration (N, K, P, Ca) changes. Free-falling rain and throughfall were collected to estimate foliar leaching. Foliar concentrations of N, K, and P decreased markedly during senescence while Ca concentrations increased. The pattern of concentration change was unique for each element, and the change in N concentration was closely correlated with change in leaf color. For the study sites as a whole, leaf dry weight decreased to 70% of the original value. Of 84.2 kg N/ha in green foliage, only 22.6% was returned to the site as litter. The canopy gained 0.3 kg N/ha (0.4%) from rainfall. The 78.5% N unaccounted for is attributed to retranslocation. Similarly, from 51.4 kg K/ha; 8.2, P; and 47.8, Ca in green foliage, 9.8, 1.3, and 3.3%, respectively, were removed by leaching; 27.4, 43.7, and 85.1% were returned to the site in litter. The remaining 63.0% K, 55.0% P, and 11.5% Ca unaccounted for is attributed to retranslocation. Retranslocation and leaching of nutrients was greater on the site of higher quality. But on both sites it appears that retranslocation is an important means of retaining and conserving N, K, and P countering the effect of annual litter removal.


Phytotaxa ◽  
2013 ◽  
Vol 133 (1) ◽  
pp. 1 ◽  
Author(s):  
GLENN B. MCGREGOR

This volume provides the first detailed account of the Chroococcales of north-eastern Australia. It provides keys, morphological and ecological data for 6 families, 33 genera and 112 species, and photomicrographs and original illustrations to enable the identification of natural populations based on stable and recognizable characters observable with the aid of light microscopy. Distributional data are based on extensive surveys at 270 sites representing the major freshwater habitats including rivers and streams, palustrine and lacustrine wetlands, thermal springs, and man-made reservoirs in Queensland and the Northern Territory as well as a review of the Australian phycological literature. 


1999 ◽  
Vol 50 (2) ◽  
pp. 159 ◽  
Author(s):  
D. Walker

Lakes Barrine and Eacham, ~1.0 and 0.5 km2 area, 67 and 63 m depth respectively, lie at ~740 m a.s.l., ~17°S in north-eastern Australia. Seasonal changes in their volumes modelled from meteorological data correspond well with observations at Eacham. Temperature profiles through 6 years show summer stratification with a metalimnion at 20–30 m; in winter, near isothermy is usually attained. At Barrine, thermal stability varies between winter and summer (<500 and >4000 g-cm cm-2 respectively). Mixing is related to low ground temperatures during periods of generally low thermal stability; exceptionally it penetrates to >60 m. Oxygen saturation decreases from the surface to ~20% at the base of the euphotic zone (15–21 m) but oxygen is carried lower by mixing after which anoxia commonly rises to ~40 m. At Barrine, Fe-reducing redox (<200 mV) usually occurs below 50 m, but during mixing this boundary falls to within 1 m of the mud–water interface. The Barrine solution is dilute (total dissolved solids 55–58 mg L-1), and that of Eacham is more so. A concentrated monimolimnion has developed in the lowermost 2–3 m at Barrine but not at Eacham. Sedimentation at the middle of each lake results from the continuous deposition of open-water products punctuated by the redistribution of coarser detritus from the ‘shallows’ at times of deep mixing. The resultant laminations are preserved only at Barrine, protected by the chemical stability of the monimolimnion.


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