scholarly journals Macroecology of seed banks: The role of biogeography, environmental stochasticity and sampling

2017 ◽  
Vol 26 (11) ◽  
pp. 1247-1257 ◽  
Author(s):  
Franck Jabot ◽  
Julien Pottier
Keyword(s):  
Seed Banks ◽  
Environmental Stochasticity

Role of seed banks in the dynamics of desert communities

2008 ◽  
pp. 163-175 ◽  
Author(s):  
M. Ajmal Khan ◽  
Farhat Agha ◽  
Bilquees Gul
Keyword(s):  
Seed Banks

scholarly journals Heterogeneity in susceptible–infected–removed (SIR) epidemics on lattices

2010 ◽  
Vol 8 (55) ◽  
pp. 201-209 ◽  
Author(s):  
Franco M. Neri ◽  
Francisco J. Pérez-Reche ◽  
Sergei N. Taraskin ◽  
Christopher A. Gilligan
Keyword(s):  
Control Strategies ◽  
Random Variable ◽  
Environmental Stochasticity ◽  
Two Dimensional ◽  
Epidemic Threshold ◽  
Heterogeneous Model ◽  
Non Invasive ◽  
Mean And Variance ◽  
Invasion Threshold

The percolation paradigm is widely used in spatially explicit epidemic models where disease spreads between neighbouring hosts. It has been successful in identifying epidemic thresholds for invasion, separating non-invasive regimes, where the disease never invades the system, from invasive regimes where the probability of invasion is positive. However, its power is mainly limited to homogeneous systems. When heterogeneity (environmental stochasticity) is introduced, the value of the epidemic threshold is, in general, not predictable without numerical simulations. Here, we analyse the role of heterogeneity in a stochastic susceptible–infected–removed epidemic model on a two-dimensional lattice. In the homogeneous case, equivalent to bond percolation, the probability of invasion is controlled by a single parameter, the transmissibility of the pathogen between neighbouring hosts. In the heterogeneous model, the transmissibility becomes a random variable drawn from a probability distribution. We investigate how heterogeneity in transmissibility influences the value of the invasion threshold, and find that the resilience of the system to invasion can be suitably described by two control parameters, the mean and variance of the transmissibility. We analyse a two-dimensional phase diagram, where the threshold is represented by a phase boundary separating an invasive regime in the high-mean, low-variance region from a non-invasive regime in the low-mean, high-variance region of the parameter space. We thus show that the percolation paradigm can be extended to the heterogeneous case. Our results have practical implications for the analysis of disease control strategies in realistic heterogeneous epidemic systems.

The role of soil temperature and seed dormancy in the creation and maintenance of persistent seed banks of Nassella trichotoma (serrated tussock) on the Northern Tablelands of New South Wales

2020 ◽  
Vol 42 (2) ◽  
pp. 85
Author(s):  
Annemieke Ruttledge ◽  
Ralph D. B. Whalley ◽  
Gregory Falzon ◽  
David Backhouse ◽  
Brian M. Sindel
Keyword(s):  
Seed Bank ◽  
New South ◽  
Soil Seed Bank ◽  
Seed Banks ◽  
Early Summer ◽  
Secondary Dormancy ◽  
South Wales ◽  
The Creation ◽  
Persistent Soil Seed Bank

A large and persistent soil seed bank characterises many important grass weeds, including Nassella trichotoma (Nees) Hack. ex Arechav. (serrated tussock), a major weed in Australia and other countries. In the present study we examined the effects of constant and alternating temperatures in regulating primary and secondary dormancy and the creation and maintenance of its soil seed bank in northern NSW, Australia. One-month-old seeds were stored at 4, 25°C, 40/10°C and 40°C, in a laboratory, and germination tests were conducted every two weeks. Few seeds germinated following storage at 4°C, compared with seeds stored at 25°C, 40/10°C and 40°C. Nylon bags containing freshly harvested seeds were buried among N. trichotoma stands in early summer, and germination tests conducted following exhumation after each season over the next 12 months. Seeds buried over summer and summer plus autumn had higher germination than seeds buried over summer plus autumn plus winter, but germination increased again in the subsequent spring. Seeds stored for zero, three, six and 12 months at laboratory temperatures were placed on a thermogradient plate with 81 temperature combinations, followed by incubation at constant 25°C of un-germinated seeds. Constant high or low temperatures prolonged primary dormancy or induced secondary dormancy whereas alternating temperatures tended to break dormancy. Few temperature combinations resulted in more than 80% germination.

The Role of Soil Seed Banks in Natural Restoration of the Degraded Hunshandak Sandlands, Northern China

2009 ◽  
Vol 17 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Meizhen Liu ◽  
Gaoming Jiang ◽  
Shunli Yu ◽  
Yonggeng Li ◽  
Gang Li
Keyword(s):  
Northern China ◽  
Seed Banks ◽  
Soil Seed Banks ◽  
Natural Restoration

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.

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