Acorn germination is not enhanced near cache sites relative to random locations

2013 ◽  
Vol 91 (7) ◽  
pp. 529-532 ◽  
Author(s):  
A.R. Sipes ◽  
N.I. Lichti ◽  
R.K. Swihart
Keyword(s):  
Seedling Survival ◽  
Seedling Emergence ◽  
First Year ◽  
Oak Regeneration ◽  
Directed Dispersal ◽  
Positive Effects ◽  
Wildlife Species ◽  
Survival And Growth ◽  
Dispersal Agents

Acorns produced by oak (genus Quercus L.) trees are eaten by numerous wildlife species, many of which may also contribute to oak regeneration by dispersing acorns to favorable microhabitats. According to the directed dispersal hypothesis, seed dispersal agents may preferentially move seeds to locations that favor seedling establishment. As a case study of the directed dispersal hypothesis, we tested the hypothesis that vertebrate scatterhoarders preferentially cache acorns in locations where conditions favor germination. We planted acorns within 0.3 m of known cache sites (cache plots) and at paired random plots that were located at equal distances from the acorn source. We then monitored germination, seedling emergence, and growth over the first year. Acorns near actual cache sites germinated at lower rates than acorns in random sites, the opposite of what would be predicted by the directed dispersal hypothesis, but insufficient seedling survival prevented statistical analysis of survival and growth. These results do not support the directed dispersal hypothesis with regard to the microhabitat at cache plots, and do not address the effects of seed burial or the potential for longer term positive effects on survival of germinated seedlings.

scholarly journals Seed encrusting with salicylic acid: A novel approach to improve establishment of grass species in ecological restoration

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0242035
Author(s):  
Simone Pedrini ◽  
Jason C. Stevens ◽  
Kingsley W. Dixon
Keyword(s):  
Salicylic Acid ◽  
Seed Germination ◽  
Ecological Restoration ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Field Conditions ◽  
Grass Species ◽  
Seed Coating ◽  
Seedling Density ◽  
Survival And Growth

To achieve global ambitions in large scale ecological restoration, there is a need for approaches that improve the efficiency of seed-based interventions, particularly in overcoming the bottleneck in the transition from germination to seedling establishment. In this study, we tested a novel seed-based application of the plant stress modulator compound salicylic acid as a means to reduce seedling losses in the seed-to-seedling phase. Seed coating technology (encrusting) was developed as a precursor for optimising field sowing for three grass species commonly used in restoration programs, Austrostipa scabra, Microlaena stipoides, and Rytidosperma geniculatum. Salicylic acid (SA, 0.1mM) was delivered to seeds via imbibition and seed encrusting. The effects of SA on seed germination were examined under controlled water-limited conditions (drought resilience) in laboratory setting and on seed germination, seedling emergence, seedling growth and plant survival in field conditions. Salicylic acid did not impact germination under water stress in controlled laboratory conditions and did not affect seedling emergence in the field. However, seedling survival and growth were improved in plants grown from SA treated seeds (imbibed and encrusted) under field conditions. When SA delivery methods of imbibing and coating were compared, there was no significant difference in survival and growth, showing that seed coating has potential to deliver SA. Effect of intraspecific competition as a result of seedling density was also considered. Seedling survival over the dry summer season was more than double at low seedling density (40 plants/m2) compared to high seedling density (380 plants/m2). Overall, adjustment of seeding rate according to expected emergence combined with the use of salicylic acid via coating could improve seed use efficiency in seed-based restoration.

Ecological Studies of the Endangered Rutidosis leptorrhynchoides. II. Patterns of Seedling Emergence and Survival in a Native Grassland

1995 ◽  
Vol 43 (1) ◽  
pp. 13 ◽  
Author(s):  
JW Morgan
Keyword(s):  
Soil Moisture ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Moisture Stress ◽  
Seedling Mortality ◽  
Themeda Triandra ◽  
Established Plant ◽  
Survival And Growth ◽  
Growth Of Seedlings

The emergence, survival and growth of seedlings of the endangered Rutidosis leptorrhynchoides F.Muell. were followed in a Themeda triandra grassland during 1991 and 1992. The effect of summer irrigation on seedling survival was also investigated. Seedling emergence occurred in both years within 2 weeks of the 'autumn break' when soil moisture rose above 20%. Ninety percent of emergence was observed within 4 weeks of the onset of germination and 87% of seedlings were within 20 cm of an established plant. No emergence was observed after 8 weeks. Thirteen percent of the 1991 cohort survived for 14 months. Mortality of most seedlings (63%) was attributed to soil moisture stress in summer. Small seedlings (Ͱ4 3 leaves) were no more susceptible to drought than larger seedlings. Seventy two percent of the 1991 cohort produced four leaves before subsequently dying. In 1992, however, most early seedling mortality was amongst cotyledonary seedlings. No seedlings flowered in their first year. Above-ground growth was slow and by 14 months, 60% of surviving seedlings had seven or fewer live leaves. Irrigation in a year of below-average rainfall had no significant effect on the survival and growth of seedlings. This suggests that seedling recruitment is not restricted to climatically favourable years (i.e. is not episodic) but rather, is potentially on-going provided suitable microsites are available for seedling survival.

Seedbanks and seedling emergence of saffron thistle (Carthamus lanatus) in eastern Australian pastures

2002 ◽  
Vol 53 (12) ◽  
pp. 1327 ◽  
Author(s):  
B. S. Grace ◽  
A. W. Sheppard ◽  
R. D. B. Whalley ◽  
B. M. Sindel
Keyword(s):  
Weed Management ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
First Year ◽  
Seed Loss ◽  
Eastern Australia ◽  
Mesh Bags ◽  
Second Year ◽  
Number Of Seeds ◽  
Over Time

Weed management has often proved difficult because of persistent seedbanks that allow recruitment to occur for many years after the weed has otherwise been controlled. The number of seeds in seedbanks of Carthamus lanatus, a widespread and troublesome weed, has not been investigated. Little is known about longevity of its seedbanks in pastures of eastern Australia.The numbers of seeds in the soil and the rate of seed loss were investigated at 3 sites in eastern Australia. Seedbanks were found to be patchy, and they had mean densities between 815 and 2290 seeds/m2 after the main germination flush. These seedbanks decreased over time and between 11 and 15% of seeds remained in the soil after 2 years without further input. More seeds were lost in the first year than in the second year, and pasture cover did not affect the rate of seed loss.Seeds buried in mesh bags and exhumed regularly showed that dormancy was lost, induced, then lost again within the 2-year experiment. Maximum seed germinability coincided with peak germination times. The likelihood of a seed producing a seedling was reduced when seeds were sown at high density. C. lanatus seeds appear to be well adapted for persistence in eastern Australian pastures by maintaining a bank of seeds that generally germinate when conditions favour seedling survival.

Root Growth Potential, First-Year Survival, and Growth of Shortleaf Pine Seedlings Show Effects of Life Date, Storage, and Family

1989 ◽  
Vol 13 (4) ◽  
pp. 163-169 ◽  
Author(s):  
S. W. Hallgren ◽  
C. G. Tauer
Keyword(s):  
Root Growth ◽  
Seedling Survival ◽  
Lateral Roots ◽  
Growth Potential ◽  
First Year ◽  
Pinus Echinata ◽  
Shortleaf Pine ◽  
Root Growth Potential ◽  
Terminal Bud ◽  
Survival And Growth

Abstract Root growth potential (RGP), and first-year field survival and growth of shortleaf pine (Pinus echinata Mill.) seedlings were significantly affected by lift date, storage, and family. Seedlings lifted in December and January showed highest RGP, survival, and growth. Storage for 28 daysalways reduced survival and growth, and the effect was greatest for late-lifted seedlings. However, for late planting, the difference in performance between freshly lifted seedlings and earlier lifted and stored seedlings may be small. Large family differences existed for seasonal changesin RGP and survival, suggesting separate management by family may be beneficial. The presence of a terminal bud and secondary needles showed little value in predicting seedling performance, whereas RGP and number of primary lateral roots were strongly correlated with seedling survival. South.J. Appl. For. 13(4):163-169.

Factors Influencing the Establishment of Seedlings of the Mallee, Eucalyptus luehmanniana (Myrtaceae)

1997 ◽  
Vol 45 (6) ◽  
pp. 997 ◽  
Author(s):  
M. G. Tozer ◽  
R. A. Bradstock
Keyword(s):  
Leaf Area ◽  
Leaf Litter ◽  
Seedling Survival ◽  
First Year ◽  
Seedling Mortality ◽  
Factors Influencing ◽  
Time Since Fire ◽  
Invertebrate Predators ◽  
Survival And Growth ◽  
Survival Of Seedlings

Factors influencing the survival of seedlings of the wet mallee-eucalypt Eucalyptus luehmanniana F.Muell. were examined using seedlings germinated in the laboratory and planted into the field. The effects of time since fire (0, 13 and 26 years), predation and position relative to adult canopy on seedling survival and growth in the first year after establishment were tested experimentally. Drought, predation by invertebrates and burial in leaf litter were identified as factors causing seedling mortality. Seedlings were most susceptible to predation at unburnt sites. Seedlings planted at burnt sites were more susceptible to drought, although a small percentage were killed by invertebrate predators. Burial of seedlings in leaf litter was most common under eucalypt canopies. After 200 days, seedlings in burnt sites were significantly more advanced in height, leaf area and leaf number than those in unburnt sites. It is predicted that E. luehmanniana seedlings are unlikely to achieve fire tolerance before fire occurs (assuming a fire interval of 10–20 years) unless they establish immediately after fire. The results suggest that mass establishment cued by fire allows seedlings to avoid predation, however mortality due to drought was greater at burnt sites than mortality due to predation at unburnt sites.

Impact of sowing, canopy cover and litter on seedling dynamics of two Polylepis species at upper tree lines in central Ecuador

2007 ◽  
Vol 23 (3) ◽  
pp. 309-318 ◽  
Author(s):  
Arne Cierjacks ◽  
Juan Enrique Iglesias ◽  
Karsten Wesche ◽  
Isabell Hensen
Keyword(s):  
Linear Models ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Canopy Cover ◽  
Climatic Conditions ◽  
First Year ◽  
Tree Line ◽  
Seedling Dynamics ◽  
Log Linear

Failure of reproduction is hypothesized as being a main reason for the formation of upper tree lines but there is, as yet, little supportive evidence of such. This study investigates the effects of experimental sowing, canopy cover and litter depth on seedling emergence and survival of Polylepis incana and Polylepis pauta at the upper distribution limit of the species in the Páramo de Papallacta, central Ecuador. We established 18 study plots located in the interior, at the edge and at the exterior of closed forests at the upper tree line and analysed seedling dynamics for 1 y following experimental sowing with four different litter treatments. For both species, seedling numbers were significantly higher in the forest interior than outside, and higher in the treatments with the litter layer removed. In P. pauta, sowing significantly increased seedling number, which was more pronounced within and at the edge of the forest than outside. In contrast, there was no impact of sowing on seedling emergence in P. incana. First-year seedling survival and mean growth rate per month were low in both species. Log-linear models did not reveal significant interactions between survival and canopy cover or litter removal. Our data show that seedling recruitment is limited at the upper tree line – presumably due to extreme climatic conditions – which indicates the importance of constraints in sexual regeneration for tree-line formation in central Ecuador.

scholarly journals Seed encrusting with salicylic acid: a novel approach to improve establishment of grass species in ecological restoration

2020 ◽  
Author(s):  
Simone Pedrini ◽  
Jason C. Stevens ◽  
Adam Cross ◽  
Kingsley W. Dixon
Keyword(s):  
Salicylic Acid ◽  
Ecological Restoration ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Field Conditions ◽  
Grass Species ◽  
Seed Coating ◽  
Seeding Rate ◽  
Significant Difference ◽  
Survival And Growth

AbstractTo achieve global ambitions in large scale ecological restoration, there is a need for approaches that improve the efficiency of seed-based restoration, particularly in overcoming the bottleneck in the transition from germination to seedling establishment. In this study we tested a novel seed-based application of the plant stress modulator compound, salicylic acid, as a means to reduce seedling losses in seed-to-seedling phase. First-time seed coating technology (encrusting) was developed as a precursor for optimising field sowing for three grass species commonly used in restoration programs, Austrostipa scabra, Microlaena stipoides, and Rytidosperma geniculata. Salicylic acid (SA, 0.1mM) was delivered to seeds via imbibition and seed encrusting with the effects tested on seed germination under controlled conditions (to test for resilience to drought), and in field conditions on seedling emergence, plant survival, and seedling growth. SA did not significantly impact germination under water stress in controlled laboratory condition and did not affect seedling emergence in the field. However, seedling survival and growth was improved in plants from SA treated seeds (imbibed and encrusted) under field conditions. When SA delivery mechanisms of imbibing and coating were compared, there was no significant difference in survival and growth, showing that seed coating has potential to deliver SA. Effect of intraspecific competition as a result of seedling density was also considered. Seedling survival over the dry summer season more than doubled when seed was sown at low density (40 plants/m2) compared to high density seeding (380 plants/m2). Overall, adjustment of seeding rate according to expected emergence combined with the use of salicylic acid is a cost-effective means for improving seed use efficiency in seed-based restoration.

scholarly journals Converting Stands of Low-Grade Hardwoods to Loblolly Pine: Stimulating Growth and Reducing Costs Through Litter Retention

1998 ◽  
Vol 22 (3) ◽  
pp. 148-155 ◽  
Author(s):  
E.S. Gardiner ◽  
J.L. Yeiser
Keyword(s):  
Soil Moisture ◽  
Loblolly Pine ◽  
Seedling Survival ◽  
Chemical Reduction ◽  
First Year ◽  
Low Grade ◽  
Herbaceous Biomass ◽  
Stand Conversion ◽  
Survival And Growth ◽  
Reducing Costs

Abstract Conversion of upland, low-grade hardwood stands to pine commonly includes hardwood competition control followed by burning of the site prior to planting. These practices risk erosion of sloped, thin soils. Litter retention provides mulch for newly planted seedlings, potentially increasing soil retention, moisture, and nutrient availability and reducing herbaceous competition without herbicides. This study assessed: (1) litter development, (2) levels of herbaceous biomass and soil moisture, and (3) pine seedling survival and growth resulting from litter retention incorporated into two approaches to stand conversion—inject and plant or underplant and release. A conventional preplant injection and burn prescription was the standard for comparison. When compared with conventional methods, conversion methods with litter retention significantly (1) reduced first- and second-year herbaceous biomass, (2) improved first-year soil moisture, (3) enhanced seedling growth and (4) eliminated the need for burning and first-year chemical reduction of herbs, thereby improving the economics of investment in these poor sites. South. J. Appl. For. 22(3):148-155.

The Implementation of Biological Phosphorus and Nitrogen Removal with the Bio-Denipho Process on a 265,000 PE Treatment Plant

1992 ◽  
Vol 25 (4-5) ◽  
pp. 161-168 ◽  
Author(s):  
J. Einfeldt
Keyword(s):  
Nitrogen Removal ◽  
Treatment Plant ◽  
First Year ◽  
In Series ◽  
Design Loads ◽  
Last Stage ◽  
Two Stages ◽  
The City ◽  
Biological Phosphorus

A process, called Bio-Denipho, for combined biological phosphorus and nitrogen removal in a combination of an anaerobic tank and two oxidation ditches is described. In this process the anaerobic tank consisting of three sections working in series is followed by two oxidation ditches. These too are working in series, but with both inlet to and outlet from the tanks changing in a cycle. The Bio-Denipho process is described specifically for the process itself and as a case study for the implementation of the process on a 265,000 pe wastewater treatment plant for the city of Aalborg in Denmark. The plant was designed and erected in two stages and the last stage was inaugurated October 31,1989. Lay-out and functions for the plant is described and design loads, plan lay-out and tank volumes are given in this paper together with performance data for the first year in operation.

Sign in / Sign up

Export Citation Format

Share Document