Environmental factors controlling the distribution of forbs on coastal foredunes in Cape Hatteras National Seashore

1974 ◽  
Vol 52 (5) ◽  
pp. 1057-1073 ◽  
Author(s):  
A. G. van der Valk

Shifting sand, which either buries the seeds or seedlings of dune forbs or carries them away, is responsible for the absence of forbs on the front of the foredune and in other zones accumulating sand regularly. Experimental work with the seedlings of six dune forbs showed that they can withstand burial by no more than 5 cm of sand and that their seeds can survive burial under only 1 to 16 cm, depending on the species. At least 20 to 30 cm of sand normally accumulates each winter in a zone subject to regular sand deposition. Salt spray plays a secondary role in preventing the establishment of forbs on the front of the foredune. It is responsible for the elimination of species which may occasionally escape burial during the winter months and which happen to be susceptible to salt spray injury. Measurements of soil moisture, soil nutrients, and soil temperatures indicate that these factors differ only slightly on the front, top, and back of the foredune. These three factors, then, appear to have little influence on the distribution of the forbs.


Author(s):  
V. N. Suleimanova ◽  
N. Yu. Egorova

The object of our research was one of the most common orchids in the world – Cypripedium calceolus L. As a rare species, it is listed in the Red book of the Russian Federation (3 category of rarity) [8], the Kirov region (3 category of rarity) [9], as well as in the Red books of 59 regions of the Russian Federation [2]. Limiting factors in the Kirov region are the violation of habitats as a result of anthropogenic impacts – deforestation, recreation, collection for bouquets, digging, reducing the number of species. Studies on the study of C. calceolus in the Kirov region are isolated [10–12]. The purpose of this work is to identify phytocenotic parameters and environmental conditions of C. calceolus habitats within the southern taiga fragment of the range. Studies of ecological and cenotic conditions of C. calceolus habitats were conducted in southern taiga forest ecosystems within the Kirov region (Slobodskaya, Afanasyevsky districts) (See table 1) in the period from 2012 to 2019. The studied habitats of C. calceolus are confined to non-morally-boreal-small-grass and grass spruce forests (Melico nutantis-Piceetum abietis subass. typicum, Maianthemo-Piceetum subass. typicum var. typical) (See fig. 1), pine trees with fir and spruce of various grasses (Melico nutantis-Pinetum sylvestris var. Lathyrus vernus). The growth of C. calceolus on the technogenically disturbed substrate of an old spent limestone quarry overgrown with coniferous rocks and various grasses was also noted. All the studied biotopes are characterized by a large constancy of non-moral species with not significant coverage of mosses. The stand of spruce forest types is dominated by Picea abies, pine-Pinus sylvestris. Abies sibirica occurs as an impurity. The undergrowth layer has a diverse species composition: Sorbus aucuparia, Frangula alnus, Lonicera xylosteum, Yuniperus communis, Daphne mezereum. In this tier of most studied phytocenoses there is a Atragene sibirica. The grass-shrub layer is also very diverse, which determines the high specificity of these communities. In addition to species of boreal small grass (Maianthemum bifolium, Orthilia secunda, Luzula pilosa, Rubus saxatilis), the presence of non – morals is characteristic-Lathyrus vernus, Melica nutans, Stellaria holostea, Asarum europaeum. Moss-lichen layer is fragmentary (covering up to 45 %), Pleurozium schreberi and Hylocomium splendens act as sodominants. Phyto-indication of the studied C. calceolus habitats according to ten ecological scales of D. N. Tsyganov (See table 2, Fig. 2) showed that in relation to the complex of all environmental factors, the studied species is mesovalent (MV) (It total = 0.54) and has an average level of lability in relation to the studied environmental factors. In relation to the complex of all environmental factors, C. calceolus is a mesobiont species. On a scale of soil acidity, the species is semistarvation at termokhimicheskie and apolitically scale and dial illumination-shading – metavalent on the scale of the wealth of the soil nitrogen – hemimillennial at createmotions scale and the scale of continentality of the climate avivamento. Only on the scale of soil moisture and the scale of soil salt regime, C. calceolus is stenovalent, which indicates a very limited range of possible habitats for this factor. The species, in the studied habitats, realizes from 4.61 to 23.84 % of its potential according to the studied factors. For C. calceolus, the results obtained allow us to extend the scale of soil acidity by 0.75 degrees to the right. According to the other scales, the values of the ecological space of the studied CP are placed in the ranges given by D. N. Tsyganov for this type Edaphic conditions of C. calceolus on the scale of soil moisture correspond to regimes from dry-saline to wet-forest-saline; on the factor of soil salt regime-poor soils; soil acidity – acidic-slightly acidic soils; soil richness in nitrogen – nitrogen – poor soils; moisture variability-soils with relatively stable and poorly variable moisture.







1998 ◽  
Vol 78 (1) ◽  
pp. 115-126 ◽  
Author(s):  
R. L. Fleming ◽  
T. A. Black ◽  
R. S. Adams ◽  
R. J. Stathers

Post-harvest levels of soil disturbance and vegetation regrowth strongly influence microclimate conditions, and this has important implications for seedling establishment. We examined the effects of blading (scalping), soil loosening (ripping) and vegetation control (herbicide), as well as no soil disturbance, on growing season microclimates and 3-yr seedling response on two grass-dominated clearcuts at different elevations in the Southern Interior of British Columbia. Warmer soil temperatures were obtained by removing surface organic horizons. Ripping produced somewhat higher soil temperatures than scalping at the drier, lower-elevation site, but slightly reduced soil temperatures at the wetter, higher-elevation site. Near-surface air temperatures were more extreme (higher daily maximums and lower daily minimums) over the control than over exposed mineral soil. Root zone soil moisture deficits largely reflected transpiration by competing vegetation; vegetation removal was effective in improving soil moisture availability at the lower elevation site, but unnecessary from this perspective at the higher elevation site. The exposed mineral surfaces self-mulched and conserved soil moisture after an initial period of high evaporation. Ripping and scalping resulted in somewhat lower near-surface available soil water storage capacities. Seedling establishment on both clearcuts was better following treatments which removed vegetation and surface organic horizons and thus enhanced microclimatic conditions, despite reducing nutrient supply. Such treatments may, however, compromise subsequent stand development through negative impacts on site nutrition. Temporal changes in the relative importance of different physical (microclimate) and chemical (soil nutrition) properties to soil processes and plant growth need to be considered when evaluating site productivity. Key words: Microclimate, soil temperature, air temperature, soil moisture, clearcut, seedling establishment



1951 ◽  
Vol 4 (3) ◽  
pp. 211
Author(s):  
GC Wade

The disease known as white root rot affects raspberries, and to a less extent loganberries, in Victoria. The causal organism is a white, sterile fungus that has not been identified. The disease is favoured by dry soil conditions and high soil temperatures. It spreads externally to the host by means of undifferentiated rhizomorphs; and requires a food base for the establishment of infection. The spread of rhizomorphs through the soil is hindered by high soil moisture content and consequent poor aeration of the soil.



2021 ◽  
Author(s):  
Lisa Baron

In 2018 and 2019 the Southeast Coast Network (SECN), with assistance from park staff, collected long-term shoreline monitoring data at Cape Hatteras National Seashore as part of the National Park Service (NPS) Vital Signs Monitoring Program. Monitoring was conducted following methods developed by the NPS Northeast Coastal and Barrier Network and consisted of mapping the high-tide swash line using a Global Positioning System unit in the spring of each year (Psuty et al. 2010). Shoreline change was calculated using the Digital Shoreline Analysis System (DSAS) developed by the United States Geological Survey (USGS; Himmelstoss et al. 2018). Following the same field methods used for monitoring long-term shoreline change, geospatial data were collected as part of the Hurricane Dorian (or Dorian) Incident Response from September 12–16, 2019. This report summarizes the post-Dorian data and the previous two shoreline data collection efforts (spring 2019 and fall 2018).



2018 ◽  
Vol 25 (03) ◽  
pp. 1850074
Author(s):  
YAN SHEN ◽  
PRASANTA K. SAHOO ◽  
YIPENG PAN

In order to enhance the corrosion resistance of mooring chain, the composite coatings are carried out on the surface of 22MnCrNiMo steel for mooring chain by double-pulsed electrodeposition technology using centrifugal force in the rotating device. The microstructure and anti-corrosion performance of the composite coatings have been investigated experimentally. This paper mainly focuses on the experimental work to determine the structural characteristics and corrosion resistance of composite coatings in the presence of nano-SiC. The results show that the presence of nano-SiC has a significant effect on the preparation of composite coating during the process. The surface of the coating becomes compact and smooth at a moderate concentration of nano-SiC particles. Furthermore, the best corrosion resistance of the composite coatings can be obtained when the concentration of nano-SiC particles is 2.0[Formula: see text]g.L[Formula: see text] after salt spray treatment.



2014 ◽  
Vol 11 (19) ◽  
pp. 5567-5579 ◽  
Author(s):  
Y. Kim ◽  
K. Nishina ◽  
N. Chae ◽  
S. J. Park ◽  
Y. J. Yoon ◽  
...  

Abstract. The tundra ecosystem is quite vulnerable to drastic climate change in the Arctic, and the quantification of carbon dynamics is of significant importance regarding thawing permafrost, changes to the snow-covered period and snow and shrub community extent, and the decline of sea ice in the Arctic. Here, CO2 efflux measurements using a manual chamber system within a 40 m × 40 m (5 m interval; 81 total points) plot were conducted within dominant tundra vegetation on the Seward Peninsula of Alaska, during the growing seasons of 2011 and 2012, for the assessment of driving parameters of CO2 efflux. We applied a hierarchical Bayesian (HB) model – a function of soil temperature, soil moisture, vegetation type, and thaw depth – to quantify the effects of environmental factors on CO2 efflux and to estimate growing season CO2 emissions. Our results showed that average CO2 efflux in 2011 was 1.4 times higher than in 2012, resulting from the distinct difference in soil moisture between the 2 years. Tussock-dominated CO2 efflux is 1.4 to 2.3 times higher than those measured in lichen and moss communities, revealing tussock as a significant CO2 source in the Arctic, with a wide area distribution on the circumpolar scale. CO2 efflux followed soil temperature nearly exponentially from both the observed data and the posterior medians of the HB model. This reveals that soil temperature regulates the seasonal variation of CO2 efflux and that soil moisture contributes to the interannual variation of CO2 efflux for the two growing seasons in question. Obvious changes in soil moisture during the growing seasons of 2011 and 2012 resulted in an explicit difference between CO2 effluxes – 742 and 539 g CO2 m−2 period−1 for 2011 and 2012, respectively, suggesting the 2012 CO2 emission rate was reduced to 27% (95% credible interval: 17–36%) of the 2011 emission, due to higher soil moisture from severe rain. The estimated growing season CO2 emission rate ranged from 0.86 Mg CO2 in 2012 to 1.20 Mg CO2 in 2011 within a 40 m × 40 m plot, corresponding to 86 and 80% of annual CO2 emission rates within the western Alaska tundra ecosystem, estimated from the temperature dependence of CO2 efflux. Therefore, this HB model can be readily applied to observed CO2 efflux, as it demands only four environmental factors and can also be effective for quantitatively assessing the driving parameters of CO2 efflux.



2021 ◽  
Vol 39 (3) ◽  
pp. 115-122
Author(s):  
Zachary Singh ◽  
Adam Maggard ◽  
Rebecca Barlow ◽  
John Kush

Abstract Longleaf pine (Pinus palustris Mill.), and slash pine (Pinus elliottii Engelm.) are two southern pine species that are popular for producing pine straw for landscaping. The objective of this research was to determine the response of soil properties and weed growth to the application of pine straw. Longleaf pine, slash pine, and two non-mulched controls (with and without chemical weed control) were tested. Volumetric soil water content, soil nutrients, soil temperature, weed biomass, and seedling growth were measured. Compared to non-mulched controls, both longleaf and slash pine plots had a greater soil moisture during extended periods without rainfall in the full sun environment. When soil temperatures increased, mulched plots had lower soil temperature relative to non-mulched plots. Soil pH and soil nutrients were generally similar between pine straw types with few significant differences in measured variables. Both pine straw treatments reduced weed growth and longleaf pine maintained a greater straw depth over the study period compared to slash pine, but no differences were observed for decomposition. These results indicate that longleaf pine straw and slash pine straw perform equally as well in terms of increasing soil moisture, moderating soil temperature, and reducing weed growth compared to not using mulch. Index words: Pinus elliottii, Pinus palustris, organic mulch, soil properties, landscaping. Species used in this study: Shumard oak, Quercus shumardii Buckl., Eastern redbud, Cercis canadensis L.



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