Combined effects of water column nitrate enrichment, sediment type and irradiance on growth and foliar nutrient concentrations of Potamogeton alpinus

2005 ◽  
Vol 50 (9) ◽  
pp. 1537-1547 ◽  
Author(s):  
GER BOEDELTJE ◽  
ALFONS J. P. SMOLDERS ◽  
JAN G. M. ROELOFS
1996 ◽  
Vol 23 (2) ◽  
pp. 185 ◽  
Author(s):  
SA Munks ◽  
R Corkrey ◽  
WJ Foley

The distribution of the koala (Phascolarctos cinereus) and the common brushtail possum (Trichosurus vulpecula) within the Prairie-Torrens Creek Alluvials province of the Desert Upland region of north-western Queensland was examined. The optimum habitat for each species as indicated by the occurrence of faecal pellet groups was found to be that associated with creek-lines. However, other land types were also used by each species to varying degrees. The relationship between various habitat variables and pellet group counts was investigated using Multiple regression and a Generalised linear model. Proximity to creek-bed, total basal area of trees, species richness and Acacia basal area (negative) best explained the occurrence of koalas. Proximity to creek-bed, Acacia basal area (negative), total basal area of trees, and available water (negative) best explained the occurrence of brushtail possums. In contrast to studies of arboreal species in the moist-south-eastern forests of Australia no relationship was found between foliar nutrient concentrations and the occurrence of koalas or brushtail possums. However, a significant relationship was found between leaf water concentration and the occurrence of koalas. It is suggested that water availability is the paramount factor defining preferred arboreal habitat in arid and semi-arid woodlands.


2013 ◽  
Vol 59 (No. 8) ◽  
pp. 306-318 ◽  
Author(s):  
I. Kuneš ◽  
M. Baláš ◽  
V. Balcar ◽  
D. Kacálek ◽  
K. Millerová ◽  
...  

We evaluated the potential of crushed amphibolite and artificial slow-release N-P-K-Mg fertiliser to stimulate the survival, growth and nutrition of Norway spruce planted on an acidified air-polluted mountain site. Control plots and treatments with slow-release fertiliser (SRF) and amphibolite (AMT) were installed. In the SRF, forty grams of tabletted amendment were applied in the close vicinity of the trees. In the AMT, two kilograms of amendment were incorporated into the soil inside the planting hole of each tree at planting. The SRF application resulted in a significant growth stimulation of spruces. The growth stimulation by amphibolite was perceptible but not significant; this amendment, however, significantly reduced mortality. None of the amendments induced marked changes in foliar nutrient concentrations.  


1993 ◽  
Vol 23 (4) ◽  
pp. 743-748 ◽  
Author(s):  
André J. Hudson

The natural invasion of mountain alder (Alnuscrispa (Ait.) Pursh) into monoculture plantations of black spruce (Piceamariana (Mill.) B.S.P.) and Sitka spruce (Piceasitchensis (Bong.) Carr.) afforded an opportunity to assess the effects of mountain alder on soils, and on the growth, nutrient status, and survival of spruce in eastern Newfoundland. The plantations were established on ploughed Kalmia–Vaccinium heath in 1968–1969. Significant increases in the growth of spruce were associated with the presence of high densities of mountain alder in the two plantations studied. The increases began 3–6 years after the invasion and establishment of mountain alder. Estimated nitrogen (N) contributions to each plantation from mountain alder leaf litter fall were approximately 50 kg•ha−1•year−1. Spruce foliage N content was 10–15% higher in high-density mountain alder (HD-alder) plots than in low-density mountain alder (LD-alder) plots, but other foliar nutrient concentrations were low and possibly deficient in the HD-alder plots. Development of a litter fall–humus layer was observed in HD-alder plots but not in LD-alder plots; however, B-horizon soil-N values did not differ significantly between HD-alder and LD-alder plots. The mountain alder invasion did not reduce the densities (stems/ha) of spruce. Additional studies on the autecology of Alnus spp. native to Newfoundland, and on alder-spruce interaction are recommended to further the development of an adequate ecological basis for heathland and peatland afforestation in the region.


1996 ◽  
Vol 74 (9) ◽  
pp. 1461-1475 ◽  
Author(s):  
Kenneth A. Barrick ◽  
Anna W. Schoettle

We tested the hypothesis of nutrient limitation in the trees of the alpine forest – tundra ecotone by comparing the foliar nutrient status of windsculpted elfinwood (also called krummholz) growing at the upper limit of tree success with symmetrically formed toll trees growing at the nearby timberline. The species investigated included Picea engelmannii (Parry) Engelmann, Abies lasiocarpa (Hooker) Nuttall, pinus flexilis james, and Pinus aristata Bailey. The foliar nutrient concentrations of the ecotone trees were similar to other healthy montane forests. Most of the significant differences in mean foliar nutrient concentrations between elfinwood and tall trees indicate lower concentrations in elfinwood trees. We found significantly lower mean phosphorus concentrations in Picea engelmannii and Abies lasiocarpa elfinwood compared with tall trees, but the mean nitrogen–phosphorus ratios were within the normal range. The foliar nutrient status of Pinus aristata elfinwood was similar to tall trees, while Pinus flexilis had considerably more significant differences in nutrient concentrations between the tree forms. Although there are many theoretical processes that could cause nutrient deficiencies at treeline, this study suggests that the elfinwood along the Colorado Front Range is not currently nutrient deficient. We discuss the potential differences in nutrient ecology between elfinwood and tall trees. Keywords: foliar nutrients, alpine ecotone, treeline, elfinwood, krummholz, conifer.


2005 ◽  
Vol 23 (2) ◽  
pp. 97-100
Author(s):  
Scott A. Derby ◽  
L. Eric Hinesley

Abstract Containerized Atlantic white cedar [Chamaecyparis thyoides (L.) B.S.P.] seedlings were fertilized with five rates (0.0, 2.4, 4.8, 7.2, and 9.6 kg/m3) (0, 4, 8, 12, and 16 lb/yd3) of controlled-release fertilizers (CRF) [Osmocote 15N–4.0P–10.0K (15N–9P2O5–12K2O), 12–14 month southern formulation, with micros; and Polyon 18N–2.6P–10.0K (18N–6P2O5–12K2O), 9-month formulation, with micros]. Height, stem diameter, dry mass, and foliar nutrient concentrations were evaluated after 16 weeks. Growth was affected by fertilizer source and application rate, with no interaction. In general, the response to increasing fertilization was quadratic. Osmocote yielded larger plants than Polyon, probably owing to its higher P content. Osmocote (4.8 to 7.2 kg/m3) (8 to 12 lb/yd3) or Polyon (7.2 kg/m3) (12 lb/yd3) is suggested for container-grown seedlings the first year.


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