Keystone coleopterans? Colonization by wood-feeding elmids of experimentally immersed woods in south-eastern Australia

1998 ◽  
Vol 49 (1) ◽  
pp. 79 ◽  
Author(s):  
B. G. L. McKie ◽  
P. S. Cranston
Keyword(s):  
Surface Area ◽  
Wood Species ◽  
Riparian Vegetation ◽  
Native Forest ◽  
South Eastern ◽  
Eucalyptus Wood ◽  
Eastern Australia ◽  
Forest Streams ◽  
South Eastern Australia

Macroinvertebrates on immersed woods in streams in montane south-eastern Australia respond to differences in wood taxa, according to a 4-month colonization study of experimentally positioned sticks. Xylophagous elmids (Coleoptera : Elmidae) strongly preferred local native Eucalyptus over other types of wood including non-native softer timbers (Pinus and Alnus). Where gouging elmids were abundant (in native forest streams with native riparian vegetation), immersed Eucalyptus wood supported high abundances of other macroinvertebrates; in their absence (in open grassland streams), Eucalyptus supported few other macroinvertebrates. Macroinvertebrate-gouged channels were present disproportionately on Eucalyptus sticks relative to other wood species. It is proposed that xylophagous elmid beetles are the principal macroinvertebrate modifiers of wood in these south-eastern Australian streams, where their gouging of channels increases surface area, thereby facilitating colonization by other macroinvertebrates and wood-decaying microorganisms and fungi.

Tree water sources over shallow, saline groundwater in the lower River Murray, south-eastern Australia: implications for groundwater recharge mechanisms

2006 ◽  
Vol 54 (2) ◽  
pp. 193 ◽  
Author(s):  
K. L. Holland ◽  
S. D. Tyerman ◽  
L. J. Mensforth ◽  
G. R. Walker
Keyword(s):  
Soil Water ◽  
Riparian Vegetation ◽  
Water Sources ◽  
Plant Water ◽  
Deep Soil ◽  
Saline Groundwater ◽  
Low Salinity ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

The decline of riparian vegetation in the lower River Murray, south-eastern Australia, is associated with a reduction in flooding frequency, extent and duration, and increased salt accumulation. The plant water sources of healthy Eucalyptus largiflorens trees growing over highly saline (>40 dS m–1) groundwater were investigated during summer when water deficit is greatest. The study found low-salinity soil water overlying highly saline groundwater at most sites. This deep soil water, rather than the saline groundwater, was identified as the plant water source at most sites. Stable isotopes of water and water potential measurements were used to infer how the deep soil water was recharged. The low-salinity, deep soil water was recharged in the following two ways: (1) vertically through the soil profile or via preferential flow paths by rainfall or flood waters or (2) horizontally by bank recharge from surface water on top of the saline groundwater. Vertical infiltration of rainfall and floodwaters through cracking clays was important for trees growing in small depressions, whereas infiltration of rainfall through sandy soils was important for trees growing at the break of slope. Bank recharge was important for trees growing within ∼50 m of permanent and ephemeral water bodies. The study has provided a better understanding of the spatial patterns of recharge at a scale relevant to riparian vegetation. This understanding is important for the management of floodplain vegetation growing in a saline, semi-arid environment.

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