Seed bank dynamics of a serotinus, fire-sensitive Banksia species

1988 ◽  
Vol 36 (2) ◽  
pp. 193 ◽  
Author(s):  
BB Lamont ◽  
MJ Barker

Banksia burdettii is a locally abundant shrub restricted to a small area in south-western Australia. At the study site, the canopy-stored seed bank built up exponentially with plant age to yield a mean of 830 viable seeds per plant from about 212 000 ovules produced over 16 years. Seed availability was the net result per year of number of flower heads, extent of head removal by cockatoos, number of florets per head and number of fruits (follicles) per floret in the production phase and the extent of seed abortion, insect granivory, seed senescence and spontaneous seed release in the mortality phase. Plants are killed by fire and a substantial proportion of cones was consumed by a hot fire. Up to 87% of viable seed may survive and be released within 100 days of a fire, depending on intensity and season of burn. Plants which died in the absence of fire released little viable seed subsequently, while the remainder were consumed when fire occurred. Comparison of 25 reproductive attributes between B. burdettii and another two Banksia species occurring in the vicinity indicated that it has much in common with these serotinous, non-sprouters. Although viable canopy-stored seeds account for few of the original ovules, reproductive inefficiency, once a fire interval of 10 years is exceeded, cannot explain the restricted distribution of this species.

1991 ◽  
Vol 39 (4) ◽  
pp. 385 ◽  
Author(s):  
ETF Witkowski ◽  
BB Lamont ◽  
SJ Connell

Seed bank dynamics of three co-occurring, non-sprouting Banksia species (B. baxteri, B. speciosa and B. coccinea) in patch-burnt scrub-heath (aged 10 and 21 years) were studied in the southern sandplains of Western Australia. In the younger plants, canopy seed storage was highest in B. coccinea. However, 21-year-old B. coccinea stored an order of magnitude fewer seeds than the other species and no more than young B. coccinea. Seed storage per year increased exponentially with plant age in B. speciosa and B. baxteri, whereas a quadratic function, peaking at 16 years, best described seed storage in B. Coccinea. Degree of serotiny was lowest in B. coccinea. Seed abortion did not vary between age cohorts but was highest in B. coccinea. Granivory ranged from 18 to 42% and was highest in the older plants and in B. baxteri. Cockatoos removed about 20% of cones in B. baxteri and B. coccinea and 10% in B. speciosa. Experimental cone removal accelerated follicle opening, especially in B. coccinea, irrespective of whether cones were placed on the ground (simulating cockatoo removal) or reattached to the plant (simulating plant death). Half the 21-year-old B. coccinea were dead and the remainder were considered senescent, as most branches showed dieback and cone fertility had fallen to 8%. Death of the other species was negligible, with cone fertility rising to a mean of 45% (B. speciosa) and 66% (B. baxteri). Interfire establishment was significant only in B. coccinea. The build-up of a viable seed bank with time occurred at a slower rate than for non-sprouting banksias in the northern sandplains.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Itzel Guzmán-Vázquez ◽  
Silvia Castillo-Argüero ◽  
Alma Orozco-Segovia ◽  
Margarita Collazo-Ortega

Background: Soil and aerial seed banks directly affect recruitment in plant populations. Soil banks result as the balance between seed inputs and outputs. Seed bank dynamics vary by species and environmental conditions. Few records on cacti seed banks are available. Questions: What types of seed banks do two cacti genera form in a lava-field reserve? Does seasonality influence the seed bank dynamics? Are inputs and outputs associated to the microenvironment? Studied species: Opuntia tomentosa, O. lassiacantha, Mammillaria haageana subsp. san-angelensis, M. magnimamma. Study site and dates: Xerophytic shrubland in the “Reserva Ecológica del Pedregal de San Ángel” in Mexico City. 2016 to 2018. Methods: We collected soil samples from four microenvironments during the rainy and the dry seasons, searched for seeds and tested their viability. We compared the number of inputs, outputs and viable seed by microenvironment and season. For M. magnimamma, each month we registered fruit maturation and searched for seeds remaining between tubercles. Results: Opuntia seed bank inputs occurred in all microenvironments and in both seasons. Rain favored inputs in hollows by secondary seed dispersal. We registered a large number of outputs caused by germination, granivory and loss of viability. Opuntia seed bank was developed in headland, plain and slope. No Mammillaria seed inputs were found, neither an aerial bank in M. magnimamma. Conclusion: Opuntia seed banks were restricted to microenvironments that provided “safe sites” which stored viable seeds. Mammillaria seed dynamics may hinders recruitment for their populations.


2010 ◽  
Vol 3 (3) ◽  
pp. 327-333 ◽  
Author(s):  
Matthew M. Cousins ◽  
Jeanne Briggs ◽  
Ted Whitwell ◽  
Chuck Gresham ◽  
Jack Whetstone

AbstractBeach vitex is an invasive plant of coastal areas of the southeastern United States from Maryland to Georgia. Many resources have been dedicated to the control of established beach vitex stands. Successful eradication will require knowledge of this plant's ability to reestablish from seed after control efforts. To understand seed-based regenerative potential, studies were conducted to characterize the fruits and seeds, document the existence and size of seed banks, determine stratification requirements for germination, and ascertain seed dormancy mechanisms. Studies of fruit lots from three consecutive years (2003 to 2005) found that the average fruit contained 1.39 seeds, and more than 76% of fruits contained at least one viable seed. A positive correlation existed between seed number and both fruit mass and fruit diameter. A substantial soil seed bank was discovered that contained viable seeds 4 yr after vegetation removal. Stratification was required for seed germination. All stratification treatments induced germination, with highest rates realized when stratification was performed at 10 C for 8 or 12 wk. Germination rates were modestly increased (from 0 to 17%) through mild scarification in the absence of stratification. Results indicate that beach vitex has physical (fruit coat) and physiological (seed) dormancy mechanisms that are capable of delaying germination for multiple seasons, allowing development of a soil seed bank. Beach vitex can reestablish from seed after vegetation removal.


1989 ◽  
Vol 3 (1) ◽  
pp. 166-169 ◽  
Author(s):  
David L. Zamora ◽  
Donald C. Thill

Seedling emergence and seed bank longevity were followed in field experiments with natural populations of common crupina for 4 yr. Emergence the first fall after dissemination was 90 to 98% of all seedlings eventually to emerge from the seedbank. Seedling emergence over time did not differ between plots which either were treated with the potassium salt of picloram or were hand weeded. No viable seed remained in the soil 25 to 26 months after seed production stopped. Five locations in a common crupina infestation undergoing eradication were sampled for seed in the soil. No viable seeds were found during the first year of the eradication, and no intact seeds were found after 4 yr.


Plant Ecology ◽  
2021 ◽  
Vol 222 (5) ◽  
pp. 647-657
Author(s):  
Alejandro Polo ◽  
Alba Fragoso ◽  
María D. Infante-Izquierdo ◽  
Francisco J. J. Nieva ◽  
Adolfo F. Muñoz-Rodríguez ◽  
...  

2005 ◽  
Vol 21 (2) ◽  
pp. 223-226 ◽  
Author(s):  
D. A. Fornara ◽  
J. W. Dalling

Many tropical pioneer species depend on the presence of high seed densities in the soil for successful recruitment following canopy disturbance (Cheke et al. 1979, Dalling & Hubbell 2002, Guevara Sada & Gómez Pompa 1972, Whitmore 1983). However determinants of variation in the composition and abundance of soil seed banks remain poorly understood. Seed bank densities can be affected by rates of seed predation and pathogen infection on the surface and in the soil, by intrinsic rates of loss in viability following dispersal, and by variation in the timing and duration of fruit production (Dalling et al. 1997, Garwood 1983, Murray & Garcia 2002). Here we compare seasonal fluctuations in seed bank density in five Panamanian forests varying in elevation and seasonality of precipitation (Table 1). We predict that lowland forests should show stronger intra-annual fluctuation in seed bank densities than montane forests because seed production and loss rates should be higher under conditions of greater resource availability, and where consistent high temperatures support greater abundance or activity of seed predators and pathogens (Brühl et al. 1999). Secondly, among lowland sites, we predict greater fluctuations in seed bank densities at drier, more seasonal sites where seasonally favourable conditions for seedling recruitment may select for interspecific synchrony in fruit production (Daubenmire 1972, Garwood 1983).


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