Soil seed bank composition over desert microhabitats: patterns and plausible mechanisms

2004 ◽  
Vol 82 (12) ◽  
pp. 1809-1816 ◽  
Author(s):  
Luis Marone ◽  
Víctor R Cueto ◽  
Fernando A Milesi ◽  
Javier Lopez de Casenave
Keyword(s):  
Seed Production ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Bare Soil ◽  
Seed Density ◽  
Seed Composition ◽  
Monte Desert ◽  
Total Seed ◽  
Seed Dynamics ◽  
Primary Dispersal

We assessed soil seed bank composition and size over several microhabitats of two habitats of the central Monte Desert of Argentina (open Prosopis woodland and Larrea shrubland) to analyse differences among them. Seed densities were similar to those already reported for other deserts, but we found consistent differences in seed composition among microhabitats. Whereas grass seeds (e.g., Aristida, Pappophorum, Neobouteloua, Trichloris, Digitaria) prevailed in natural depressions of open areas, forb seeds (e.g., Phacelia, Lappula, Descurainia, Plantago, Chenopodium) were more abundant under trees. The comparison of seed production during primary dispersal (i.e., seed rain) with seed density on the ground at the end of dispersal indicated that most forb seeds entered the habitat through the micro habitats located beneath the canopy of trees and tall shrubs, and remained there after redistribution. Most grass seeds, by contrast, entered it through bare-soil and under-grass microhabitats, and reached more even distributions after secondary dispersal, especially because of dramatic losses in bare soil. Patterns of plant recruitment and seed dynamics in specific microhabitats were better understood when differences of soil seed bank composition, but not of total seed density, were taken into account.Key words: Monte Desert, seed dispersal, seed predation, seed production, seeds.

The effects of recreation disturbance on subalpine seed banks in the Rocky Mountains of Montana

2000 ◽  
Vol 78 (5) ◽  
pp. 577-582 ◽  
Author(s):  
Catherine Zabinski ◽  
Todd Wojtowicz ◽  
David Cole
Keyword(s):  
Organic Matter ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Density ◽  
Soil Cores ◽  
Bare Ground ◽  
Recreation Impacts ◽  
Natural Revegetation ◽  
Site Types

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.

The role of seedbanks in invasions by Hyparrhenia hirta (L.) Stapf in Australia

2019 ◽  
Vol 41 (5) ◽  
pp. 383 ◽  
Author(s):  
Vinod K. Chejara ◽  
Paul Kristiansen ◽  
R. D. B. (Wal) Whalley ◽  
Brian M. Sindel ◽  
Christopher Nadolny
Keyword(s):  
South African ◽  
Seed Production ◽  
Seed Dormancy ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Perennial Grass ◽  
Seed Banks ◽  
Invasive Weed ◽  
South Wales ◽  
Poor Seed

Hyparrhenia hirta (L.) Stapf (also known as Coolatai grass, South African bluestem or thatching grass) has become a serious invasive weed in Australia. Within its native range, it is generally regarded as a useful grass particularly for thatching, and seed production is low with a low soil seed bank of from 2 to 200seedsm–2. Several hundred accessions of H. hirta were deliberately introduced into Australia up until the 1980s and nearly all were discarded because of poor seed production. However, at least one introduction in the 1890s in northern New South Wales (NSW), Australia, has possibly contributed to the present serious weed problem. Annual seed production from roadside stands in northern NSW ranged from 7000 to 92000seedsm–2 in 2015. The soil seed bank under dense H. hirta infestations in the same region in 2006 and 2007, was found to be ~30000seedsm–2 mostly confined to the top 2cm, with few dormant seeds and a large reduction of these numbers over the next 12 months when further seed input was prevented. Similar studies of other perennial grass weeds have found seed banks of similar sizes, but dormancy mechanisms ensure that their seed banks last for at least 10 years without further seed input. These results suggest that the present weedy populations of H. hirta have dramatically increased fecundity enabling a large seed bank to develop beneath dense stands. The development of seed dormancy and consequently a long-lived seed bank would make this weed even more difficult to control. Until seed dormancy develops, control of H. hirta in northern NSW can be effective provided further input into the seed bank can be prevented.

The impact of duration of drainage on the seed banks of northern prairie wetlands

1989 ◽  
Vol 67 (6) ◽  
pp. 1878-1884 ◽  
Author(s):  
Carol E. Wienhold ◽  
A. G. van der Valk
Keyword(s):  
Seed Bank ◽  
Seed Banks ◽  
Seed Density ◽  
Prairie Wetlands ◽  
Vegetation Surveys ◽  
The Mean ◽  
Wetland Species ◽  
Total Seed ◽  
The Impact

To determine the potential role of seed banks in the restoration of drained wetlands, the seed banks of 30 extant and 52 drained and cultivated prairie potholes were sampled in Iowa, Minnesota, and North Dakota; the potholes had been drained between 5 and 70 years ago. The midsummer vegetation of most of these potholes was also sampled. The number of species in the seed bank of a pothole declined from a mean of 12.3 in extant potholes to 7.5, 5.4, 5.0, 7.4, 3.2, and 2.1 in potholes drained up to 5, 10, 20, 30, 40, and 70 years ago, respectively. The mean total seed density of extant potholes was 3600 seeds/m2. It increased to 7000 seeds/m2 up to 5 years after drainage, but then declined rapidly to 1400, 1200, 600, 300, and 160 after up to 10, 20, 30, 40, and 70 years after drainage. Changes in both species richness and seed density with increasing duration of drainage varied from state to state. About 60% of the species present in the seed banks of extant or recently drained wetlands were not detected in wetlands that had been drained for more than 20 years. Vegetation surveys of extant and drained wetlands indicated that as many or more wetland species not detected in the seed bank were present in the vegetation, as there were wetland species in the seed bank.

Ecological Studies of the Endangered Rutidosis Leptorrhynchoides .I. Seed Production, Soil Seed Bank Dynamics, Population Density and Their Effects on Recruitment

1995 ◽  
Vol 43 (1) ◽  
pp. 1 ◽  
Author(s):  
JW Morgan
Keyword(s):  
Population Density ◽  
Seed Production ◽  
Seed Bank ◽  
Seedling Recruitment ◽  
Fire Regime ◽  
Seedling Survival ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Bank Dynamics ◽  
The Impact

The seasonal dynamics of the soil seed bank of Rutidosis leptorrhynchoides F.Muell. were studied by the seedling emergence technique. Seed longevity in soil was quantified in a seed burial and retrieval experiment. The importance of annual seed production to recruitment was also determined over a 2-year-period, as was the impact of conspecific neighbour density on seed production per inflorescence. Rutidosis leptorrhynchoides appears to form a transient seed bank with little capacity to store germinable seeds in the soil from year to year. No seedlings were observed in soil sampled after the autumn germination pulse and no viable seed was present in the soil within 16 weeks of burial. The rate of seed loss was similar when seed was buried under all intact grassland canopy and in 0.25m2 canopy gaps. It appears that most seeds simply rot in moist soil or are predated by soil invertebrates. Seedling recruitment was at least 15 times greater in plots where natural seed input occurred than where it was curtailed. Less than 10% of seed shed resulted in seedling emergence. It is suggested that recruitment in the large populations studied was limited by germination rather than by microsite availability for seedling survival. Population density had an impact on seed production with sparsely distributed individuals producing fewer seeds per inflorescence than plants from denser colonies, although there was much variation. Sparse plants produced significantly fewer seeds per inflorescence than hand crosspollinated heads suggesting reduced pollinator efficacy in these colonies relative to larger colonies where there was no such difference. Rutidosis leptorrhynchoides is dependent on the maintenance of the standing population for recruitment. Any factors that influence flowering and subsequent seed production will limit the ability of the species to regenerate. Over sufficient time, this could lead to the localised extinction of the species and may explain why R. leptorrhynchoides has failed to reappear in remnants where a suitable fire regime has been re-implemented after a period of management unfavourable to the survival, flowering and regeneration of this species.

scholarly journals Seed survival for three decades under thick tephra

2010 ◽  
Vol 20 (3) ◽  
pp. 201-207 ◽  
Author(s):  
Shiro Tsuyuzaki
Keyword(s):  
Seed Bank ◽  
Life Histories ◽  
Community Dynamics ◽  
Soil Surface ◽  
Seed Density ◽  
Genetic Changes ◽  
Seed Survival ◽  
Total Seed ◽  
Exotic Seeds

AbstractSeed longevity in situ is a prerequisite for understanding the life histories and community dynamics of species, although long-term longevity under thick tephra has not been documented because of a lack of opportunity and/or awareness. The seed bank for this study was estimated by both germination and flotation tests. Seeds of 17 species have survived with high density, having been buried under thick tephra for 30 years, since the 1977–1978 eruptions on Mount Usu, Hokkaido Island, northern Japan. The total seed density was >1000/m2. Rumex obtusifolius was the most common seed-bank species for 30 years, but decreased in density between 20 and 30 years. More seeds of Hypericum erectum occurred in deeper soil. The total seed density decreased gradually for 30 years, but H. erectum and Juncus effusus did not decline. Native seeds tended to be viable longer than exotic seeds. These results suggest that small, native seeds tend to survive longer with deep burial, while the more numerous weedy, exotic seeds located at the soil surface declined faster. The seed bank provides long-term monitoring of seed survival under natural conditions, and could be used to detect genetic changes.

Can spatial variation and inter-annual variation in precipitation explain the seed density and species richness of the germinable soil seed bank in a tropical dry forest in north-eastern Brazil?

Flora ◽  
2013 ◽  
Vol 208 (7) ◽  
pp. 445-452 ◽  
Author(s):  
Danielle Melo dos Santos ◽  
Kleber Andrade da Silva ◽  
Ulysses Paulino de Albuquerque ◽  
Josiene Maria Falcão Fraga dos Santos ◽  
Clarissa Gomes Reis Lopes ◽  
...  
Keyword(s):  
Species Richness ◽  
Spatial Variation ◽  
Seed Bank ◽  
Annual Variation ◽  
Soil Seed Bank ◽  
Tropical Dry Forest ◽  
Dry Forest ◽  
Seed Density ◽  
Eastern Brazil ◽  
North Eastern

Effect of hydroperiod on seed-bank composition in semipermanent prairie wetlands

1989 ◽  
Vol 67 (3) ◽  
pp. 856-864 ◽  
Author(s):  
Karen A. Poiani ◽  
W. Carter Johnson
Keyword(s):  
Seed Bank ◽  
Floristic Composition ◽  
Open Water ◽  
Seed Density ◽  
Prairie Wetlands ◽  
Water Zone ◽  
Significant Difference ◽  
Total Seed ◽  
Frequent Exposure

Bottom samples were collected from two semipermanent prairie wetlands to determine if known hydroperiod differences were reflected in seed-bank composition. Samples were also taken a 2nd year in one wetland to assess between-year variation. Seed density and composition were determined by counting and identifying seedlings that emerged from samples placed in a greenhouse. Most seed-bank characteristics were statistically indistinguishable between wetlands, including floristic composition and total seed density. A significant difference occurred, however, in the relative importance of mudflat annuals and émergents. The mudflat group was much more abundant in the wetland with the shorter hydroperiod (82 vs. 51%). More frequent exposure of the substrate probably yielded greater seed production. Also, a longer hydroperiod depressed seed density in the open water zone (open water zone, 1309 seeds/m2; two emergent zones, 2840 and 9893 seeds/m2). A seed-bank assay may detect subtle hydroperiod differences among wetlands of the same permanence class more quickly and economically than long-term hydrological monitoring. A sharp increase in mudflat seeds in the 2nd year of sampling after a drawdown supports the use of seed banks in determining hydroperiod events in these wetlands.

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