Buried propagule bank of a high subalpine site: microsite variation and comparisons with aboveground vegetation

1993 ◽  
Vol 71 (5) ◽  
pp. 712-717 ◽  
Author(s):  
Cheryl A. Ingersoll ◽  
Mark V. Wilson

We assessed the composition and spatial pattern of the persistent buried propagule bank (seeds and vegetative structures) of a treeline site in the Oregon Cascade Mountains. We monitored emergence from soil cores removed from four microsite types and recorded vegetation cover and seedling abundance on the site. Over 3100 seedlings/m2 emerged from the greenhouse soil cores; the seed bank was dominated by Juncus species. Few vegetative sprouts emerged. Vegetated microsites produced significantly more emergents than did bare soils, but even bare soils contained abundant seeds. Overall site cover was low and few seedlings occurred on the site. Discrepancies between aboveground and belowground abundance were common. Phyllodoce empetriformis and Luetkea pectinata were abundant in the vegetation and produced many seeds but were poorly represented in the seed bank and as seedlings on the site. Other species were abundant in the seed bank, but rare in the vegetation. Our results indicate that despite the abundance of seeds in bare soil, colonization is likely to be extremely slow. Key words: seed bank, subalpine, seedlings, microsite, spatial pattern.

1994 ◽  
Vol 72 (1) ◽  
pp. 52-58 ◽  
Author(s):  
S. P. Vander Kloet ◽  
N. M. Hill

Vegetative cover, fruiting phenology, and seed production was estimated from six Vaccinia heathlands on the Avalon Peninsula of Newfoundland so that the efficacy of the Vaccinium seed bank could be ascertained. Out of the six species of Vaccinium present in this vegetation, only V. angustifolium and V. boreale were recovered from 120 soil cores taken; V. uliginosum and V. vitis-idaea, two of the most common species on these heaths, were not represented in the seed bank at all, yet experimentally buried seeds from both these taxa will successfully germinate when exhumed after 6 years of burial. Indeed, 81% of the germinants were from taxa with dry fruits such as Kalmia, Luzula, Juncus, and Agrostis. Paucity of Vaccinium seed in the soil column may be due in part to fungal rot and avian predation. Key words: Vaccinium, seed production, seed banks, heaths.


1998 ◽  
Vol 8 (1) ◽  
pp. 39-46 ◽  
Author(s):  
Mónica B. Bertiller

AbstractThe spatial variation of the soil seed bank in the steppe of Larrea divaricata and Stipa spp. was evaluated in relation to the spatial pattern of the established vegetation, over two years. Plant distribution was expected to affect the spatial pattern of the soil seed bank. It was hypothesized that patches of bare soil are seed-limited, while soil beneath the external crown of vegetation patches contains greater numbers of seeds. The soil seed bank of the steppe of Larrea divaricata and Stipa spp. displayed a patchy distribution associated with the spatial pattern of above-ground vegetation. Seed banks in areas of bare soil showed lower numbers of seeds than those beneath vegetation. The soil seed bank was dominated by annuals, both in open areas of soil and under vegetation canopies. The relative composition of the soil seed bank varied spatially. Annuals (dicots and grasses) were more abundant in grass-shrub patches (GSP) and grass patches (GP) than in incipient grass-shrub patches (IGSP) and bare soil (BS). Seeds of perennial grasses were more abundant under GP, less abundant under grass-shrub mixed canopies (IGSP and GSP) and practically absent in BS. In addition, seeds of perennial dicots were more frequent in grass-shrub mixed canopies, scarcely represented in GP and absent in BS. The concentration of seeds of perennial grasses in GP and GSP indicates that these are essential for the maintenance of the size of grass populations. Sustainable management should be focused to maintain the structure and function of these types of vegetation patches.


Polar Biology ◽  
2021 ◽  
Vol 44 (3) ◽  
pp. 587-591
Author(s):  
Halina Galera ◽  
Agnieszka Rudak ◽  
Małgorzata Pielech ◽  
Anna Znój ◽  
Katarzyna J. Chwedorzewska ◽  
...  

AbstractDistribution of seeds of an invasive species is important for the spread of the invasion and for any directed eradication action. This distribution is driven by seed rain. We studied the influence of tussocks on the spatial pattern of seed rain and resulting population spatial pattern of an invasive Antarctic Poa annua L. population. Our hypothesis was that the tussocks trap wind-dispersed seeds. We set 40 artificial grass seed traps simulating tussocks and 40 soil seed traps (control) in the area occupied by the population. The traps were exposed for a total of 3 years and exchanged periodically. We assessed the seed bank in soil extracted for installation of our control traps. Seed number was determined by the germination method. We did not find any significant difference between the types of traps regarding the number of trapped seeds and the number of traps containing seeds, however trapping events were greater for artificial grass traps. The average size of the seed rain was 13.5 seeds m−2 year−1 and the size of the soil seed bank was 216 seeds m−2. We estimated that accumulation of the soil seed bank required around 16 years. Artificial grass discs may be more efficient than bare soil in accumulating seeds, therefore grass tussocks may influence the spatial population structure not only through local seed deposition, but also by intercepting seeds dispersed by wind. Our research further supports, that directed soil removal from underneath the tussocks is the most efficient eradication method of P. annua in Antarctica.


1989 ◽  
Vol 69 (3) ◽  
pp. 711-714 ◽  
Author(s):  
K. I. N. JENSEN ◽  
E. R. KIMBALL ◽  
J. A. IVANY

The half-life of metribuzin applied to a bare soil surface was calculated to be 3–7 d over four field tests. An artificial cover erected after application or a shallow incorporation increased the half-life of metribuzin approximately 2.5- to 3-fold. Leaching out of the 0- to 5-cm-deep sampling zone could not account for loss of metribuzin. It was concluded that metribuzin persistence may be affected by volatility and/or photodecomposition losses under field conditions, especially shortly after application. Key words: Metribuzin half-life, volatility, photodecomposition, row width


2006 ◽  
Vol 17 (5) ◽  
pp. 665-674 ◽  
Author(s):  
A.M. Gurnell ◽  
A J. Boitsidis ◽  
K. Thompson ◽  
N J. Clifford

Author(s):  
Paulo Roberto Fidelis Giancotti ◽  
Mariluce Pascoína Nepomuceno ◽  
Juliana de Souza Rodrigues ◽  
Micheli Yamauti ◽  
José Valcir Fidelis Martins ◽  
...  

Sorghum is an important crop to plant in rotation with sugarcane. This is mainly because both are inputs for the ethanol industry. Crop residues of sweet sorghum promote suppression of weed re-infestation, avoiding weed interference to the sugarcane crop due to the strong allelopathic potential of sorghum. In order to determine the suppressive effects of sorghum crop residues on weeds, a field experiment was carried out. Seven vegetation covers were used as options for crop rotation with sugarcane. The treatments were sweet sorghum, velvet bean, sunflower, soybean, sugar cane, fallow, and an area without cover. The experiment was randomized blocks with four replications of 27 m2 plots. The weed community of each plot was evaluated by phytosociological indexes at 60 and 120 days after the formation of vegetation cover. The composition of soil seed bank was also evaluated. The weeds with the highest indexes of relative importance during the evaluations were Cyperus rotundus, Raphanus raphanistrum and Parthenium hysterophorus. The diversity of the weed community, estimated by relative importance indexes, was lower in the area with velvet bean as soil cover. Sorghum, velvet bean and sunn hemp covers reduced the soil seed bank compared to the fallow treatment and the treatment without vegetation cover. Crop residues of sweet sorghum and velvet bean provide a decrease in weed infestation in field, and the weed suppression period can last up to 120 days during the dry season.


Author(s):  
Bas van Wesemael ◽  

This chapter first reviews recent pilot studies covering limited areas often with exposed bare soils. Then we focus on the challenges for large-scale application of spectral mapping when the soil and parent material are heterogeneous and surface conditions are unknown. In order to deal with these constraints we discuss i) calibration of spectral models based on large spectral libraries, ii) surface conditions that disturb the soil signal, and iii) time series of images in order to delimit cropland fields and increase the extent of bare soil that can be mapped. Finally, a case study deals with a SOC prediction map derived from the spectra of a Sentinel-2 image and calibrated using the LUCAS spectral library.


2016 ◽  
Vol 10 (1s) ◽  
Author(s):  
Paolo Bazzoffi ◽  
Rosa Francaviglia ◽  
Ulderico Neri ◽  
Rosario Napoli ◽  
Alessandro Marchetti ◽  
...  

<p>This paper shows the results of the monitoring carried out in three hilly farms of the MONACO project in order to verify the effectiveness of the Standard 1.1 <sub>(commitment a)</sub> (temporary ditches) and Standard 1.2 <sub>(commitment g)</sub> (Vegetation cover throughout the year in set-aside land) in the reduction in soil erosion, contained in Rule 1: ‘minimum land management that meets specific conditions’ of the decree Mipaaf 2009 and following modifications, until the recent decree No. 180 of January 23, 2015. In addition, the assessment of the competitiveness gap was done. That is the evaluation of the additional costs borne by the beneficiary of the single payment determined from agronomic commitments. Monitoring has also compared the erosion actually observed in the field with that predicted by RUSLE model (Revised Universal Soil Loss Equation) (Renard et al., 1997) in the two situations: with and without the presence of temporary ditches, i.e. assuming Factual (compliance rules) and in that Counterfactual (infringement). This comparison was made in view of the fact that the RUSLE model was chosen by the 'European Evaluation Network for Rural Development (EEN, 2013) as a forecasting tool for the quantification of' Common Indicator ‘soil erosion by water’. The results of soil erosion survey carried out by using a new  UAV-GIS methodology  on two monitoring farms in two years of observations have shown that temporary ditches were effective in decreasing erosion, on average, by 42.5%, from 36. 59 t ha<sup>-1</sup> to 21.05 t ha<sup>-1</sup> during the monitoring period. It was also evaluated the effectiveness of grass strips (at variance with the commitment of temporary ditches). The results showed a strong, highly significant, reduction in erosion by about 35% times respect soil erosion observed in bare soil and also a significant reduction in the volume of runoff water.  With regard to Standard 1.2 <sub>(commitment g)</sub> the statistical analysis shows a strong and highly significant decrease in the erosion due to the vegetation cover of the soil compared to bare soil. The economic competitiveness gap of  Standard 1.1<sub>(commitment a)</sub> stood at € 4.07±1.42 € ha<sup>-1</sup> year<sup>-1</sup>, while CO<sub>2</sub> emissions due to execution of temporary ditches was 2.58 kg ha<sup>-1</sup>year<sup>-1</sup>. As for the Standard 1.2 <sub>(commitment g) </sub>the average differential competitiveness gap amounted to  50.22±13.7 € ha<sup>-1</sup> year<sup>-1</sup> and an output of CO<sub>2</sub> equal to 31.52  kg ha<sup>-1</sup> year.</p>


2000 ◽  
Vol 78 (5) ◽  
pp. 577-582 ◽  
Author(s):  
Catherine Zabinski ◽  
Todd Wojtowicz ◽  
David Cole

We investigated the soil seed bank in a subalpine ecosystem with patchy disturbance from camping. Soil cores were collected from three site types, heavily impacted, lightly impacted, and undisturbed, that differed in area of bare ground and depth of surface organic matter. We hypothesized that the density and composition of the seed bank would vary with depth of surface organic matter and distance from established vegetation. Seedling emergence was determined in the greenhouse. Seed density was significantly lower on disturbed sites, averaging 441 seeds/m2 on heavily impacted sites, 1495 seeds/m2 on lightly impacted sites, and 4188 seeds/m2 on undisturbed sites. Seed density declined exponentially with distance from established vegetation and increased with depth of surface organic matter. The number of species present did not vary across site types, but 10 species that occurred on lightly impacted and undisturbed sites were not present on heavily impacted sites. We concluded that disturbance that causes removal of surface organic matter can affect natural revegetation by lowering the density of propagules and affecting the species represented in the seed bank.Key words: seed bank, subalpine, patchy disturbance, recreation impacts.


2003 ◽  
Vol 45 (1-2) ◽  
pp. 139-151 ◽  
Author(s):  
G. Kemény ◽  
Z. Nagy ◽  
Z. Tuba

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