Developmental phenology of Persoonia longifolia (Proteaceae) and the impact of fire on these events

2015 ◽  
Vol 63 (5) ◽  
pp. 415 ◽  
Author(s):  
K. A. Chia ◽  
J. M. Koch ◽  
R. Sadler ◽  
S. R. Turner
Keyword(s):  
Seedling Survival ◽  
Soil Seed Bank ◽  
Fruit Production ◽  
Early Spring ◽  
Late Winter ◽  
First Year ◽  
Land Restoration ◽  
Seed Collection ◽  
Baseline Information ◽  
The Impact

Persoonia longifolia R.Br. is a common understorey tree that is difficult to re-establish following bauxite extraction and land restoration in parts of the jarrah forest of south-western Western Australia. To improve restoration outcomes for P. longifolia, understanding its phenology is vital for developing methods for returning this plant to rehabilitated areas. The present study investigated in detail different aspects of the phenology of P. longifolia over a 3-year-period. Most vegetative growth occurred during the summer months and flowering and fruiting occurred concurrently. Fruit matured from July through to September, at which time these dropped to the forest floor. Germination occurred in late winter–early spring from fruit that was at least 1-year old, with poor seedling survival in natural bush (<10%) during the first 12 months. Following fire, P. longifolia plants resprouted prolifically in the next growing season, although there was very little fruit production in the first year following fire. Fruit was not produced until at least the second year following a fire, and when dispersed, required at least another year in the soil seed bank before germination commenced (i.e. 3 years post-fire). Results from the present study will improve restoration outcomes for this species, by providing guidance on better seed-collection strategies and baseline information concerning growth rates under natural conditions that can then be used to assess performance of this species in restored environments.

A Subice Suction Corer for Sampling Epontic Ice Algae

1988 ◽  
Vol 45 (3) ◽  
pp. 562-568 ◽  
Author(s):  
Harold E. Welch ◽  
Martin A. Bergmann ◽  
John K. Jorgenson ◽  
William Burton
Keyword(s):  
Sea Ice ◽  
Quantitative Assessment ◽  
Early Spring ◽  
Late Winter ◽  
First Year ◽  
Ice Algae ◽  
Sources Of Error

Standard SIPRE coring was compared with a new Subice Suction Corer and cores taken by diver for the quantitative assessment of epontic (subice) algae on first-year congelation sea ice at Resolute, N.W.T., Canada (≈75°N). The diver cores were probably most accurate but were slow and costly. SIPRE coring was as good as other techniques in late winter and early spring but gave progressively poorer (under) estimates as the season progressed, with up to 90% of the ice algae being lost from SIPRE cores by June. The Subice Suction Corer was fast, easy to operate, cheap, and gave results comparable with samples obtained by diving. Sources of error are discussed.

scholarly journals Salinization of Alpine rivers during winter months

2020 ◽  
Author(s):  
Georg H. Niedrist ◽  
Miguel Cañedo-Argüelles ◽  
Sophie Cauvy-Fraunié
Keyword(s):  
Ecosystem Functioning ◽  
Road Salt ◽  
Early Spring ◽  
Small Rivers ◽  
Late Winter ◽  
European Alps ◽  
Aquatic Biodiversity ◽  
Secondary Salinization ◽  
Alpine Rivers ◽  
The Impact

Abstract Human-induced (i.e., secondary) salinization affects aquatic biodiversity and ecosystem functioning worldwide. While agriculture or resource extraction are the main drivers of secondary salinization in arid and semi-arid regions of the world, the application of deicing road salt in winter can be an important source of salts entering freshwaters in cold regions. Alpine rivers are probably affected by salinization, especially in highly populated mountain regions, although this remains to be explored. In this study, we analyzed multi-year conductance time series from four rivers in the European Alps and demonstrated that the application of deicing road salt is linked to peaking rivers’ salinity levels during late winter/early spring. Especially in small catchments with more urban surfaces close to the rivers, conductance increased during constant low-flow periods in late winter and was less correlated with discharge than in summer. Thus, our results suggest that small rivers highly connected to urban infrastructures are prone to considerable salinity peaks during late winter/early spring. Given the low natural level of salinities in Alpine rivers, the aquatic biodiversity might be significantly affected by the recorded changes in conductance, with potential consequences on ecosystem functioning. Thereby, we urge the research community to assess the impact of secondary salinization in Alpine rivers and call for an implementation of management practices to prevent the degradation of these pristine and valuable ecosystems.

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 A Vernalization Response in a Winter Safflower (Carthamus tinctorius) Involves the Upregulation of Homologs of FT, FUL, and MAF

2021 ◽  
Vol 12 ◽  
Author(s):  
Darren P. Cullerne ◽  
Siri Fjellheim ◽  
Andrew Spriggs ◽  
Andrew L. Eamens ◽  
Ben Trevaskis ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Cold Treatment ◽  
Carthamus Tinctorius ◽  
Early Spring ◽  
Differentially Expressed ◽  
Late Winter ◽  
Vernalization Response ◽  
Long Read ◽  
Small Set ◽  
The Impact

Safflower (Carthamus tinctorius) is a member of the Asteraceae family that is grown in temperate climates as an oil seed crop. Most commercially grown safflower varieties can be sown in late winter or early spring and flower rapidly in the absence of overwintering. There are winter-hardy safflower accessions that can be sown in autumn and survive over-wintering. Here, we show that a winter-hardy safflower possesses a vernalization response, whereby flowering is accelerated by exposing germinating seeds to prolonged cold. The impact of vernalization was quantitative, such that increasing the duration of cold treatment accelerated flowering to a greater extent, until the response was saturated after 2 weeks exposure to low-temperatures. To investigate the molecular-basis of the vernalization-response in safflower, transcriptome activity was compared and contrasted between vernalized versus non-vernalized plants, in both ‘winter hardy’ and ‘spring’ cultivars. These genome-wide expression analyses identified a small set of transcripts that are both differentially expressed following vernalization and that also have different expression levels in the spring versus winter safflowers. Four of these transcripts were quantitatively induced by vernalization in a winter hardy safflower but show high basal levels in spring safflower. Phylogenetic analyses confidently assigned that the nucleotide sequences of the four differentially expressed transcripts are related to FLOWERING LOCUS T (FT), FRUITFUL (FUL), and two genes within the MADS-like clade genes. Gene models were built for each of these sequences by assembling an improved safflower reference genome using PacBio-based long-read sequencing, covering 85% of the genome, with N50 at 594,000 bp in 3000 contigs. Possible evolutionary relationships between the vernalization response of safflower and those of other plants are discussed.

scholarly journals Strategies for Successful Mangrove Living Shoreline Stabilizations in Shallow Water Subtropical Estuaries

2021 ◽  
Vol 13 (21) ◽  
pp. 11704
Author(s):  
Rebecca M. Fillyaw ◽  
Melinda J. Donnelly ◽  
Jason W. Litwak ◽  
Julia L. Rifenberg ◽  
Linda J. Walters
Keyword(s):  
Environmental Factors ◽  
Seedling Survival ◽  
High Water ◽  
Water Velocity ◽  
First Year ◽  
Living Shorelines ◽  
Red Mangrove ◽  
Living Shoreline ◽  
Subtropical Estuaries ◽  
The Impact

By combatting erosion and increasing habitat, mangrove living shorelines are an effective alternative to hard-armoring in tropical and subtropical areas. An experimental red mangrove living shoreline was deployed within Mosquito Lagoon, Florida, using a factorial design to test the impact of mangrove age, breakwater presence, and mangrove placement on mangrove survival within the first year of deployment. Mixed mangrove age treatments were included to identify if seedling (11-month-old) survival could be enhanced by the presence of transitional (23-month-old) and adult (35 to 47-month-old) mangroves. Environmental factors were monitored to detect possible causes of mangrove mortalities. Approximately half (50.6%) of mangroves died, and of those, 90.7% occurred within the annual high-water season, and 88.9% showed signs of flooding stress. Planting seedlings haphazardly among older mangroves did not attenuate enough wave energy to significantly increase seedling survival. Breakwaters alleviated stress through a reduction in water velocity and wave height, increasing the odds of survival by 197% and 437% when mangroves were planted in the landward and seaward rows, respectively. Compared to seedlings, deployment of adult mangroves increased survival odds by 1087%. Collectively, our results indicate that sites with a high-water season should utilize a breakwater structure and mangroves with a woody stem.

scholarly journals Estimation of Yield Loss of Jatropha Curcas Due to Aphthona Whitfieldi in Burkina Faso

2021 ◽  
Author(s):  
Alizèta Sawadogo ◽  
Issaka Zida ◽  
Marc Kenis ◽  
Souleymane Nacro
Keyword(s):  
Burkina Faso ◽  
Jatropha Curcas ◽  
Yield Loss ◽  
Insect Pest ◽  
Leaf Beetle ◽  
Fruit Production ◽  
First Year ◽  
Beetle Damage ◽  
On Farm ◽  
The Impact

Abstract In Burkina Faso, the leaf beetle Aphthona whitfieldi is the main insect pest of the biofuel plant Jatropha curcas. The beetle affects plant growth and seed yield, but the impact on yield has never been properly quantified. This study was conducted on-station and on-farm in the district of Léo, southern Burkina Faso, in 2015. It aimed at evaluating the yield losses that A. whitfieldi inflicts to J. curcas. The first experiment used 25 caged trees in their first year of fruit production, on which various amounts of beetles were released. When 200 beetles were released, the defoliation level reached 55% and caused 61% of yield loss. Releases of 400 or more beetles caused a defoliation level of at least 74% and seed losses of 98%. On-farm observations were made on attack levels and seed yields in three different types of plantations, i.e. pure plantations, plantations intercropped with food crops and hedges. These observations showed that defoliation levels over 50% were common in the three types of plantations, resulting in very low yields. This study shows the importance of beetle damage in the cultivation of J. curcas. This is likely one of the reasons for the very low yields, which, among other causes, led to the abandonment of J. curcas plantations in the region.

scholarly journals Influence of Pollen on Solar Photovoltaic Energy: Literature Review and Experimental Testing with Pollen

2020 ◽  
Vol 10 (14) ◽  
pp. 4733
Author(s):  
Carlos Sanz Saiz ◽  
Jesús Polo Martínez ◽  
Nuria Martín Chivelet
Keyword(s):  
Experimental Testing ◽  
Mass Density ◽  
Soda Lime ◽  
Float Glass ◽  
Early Spring ◽  
Late Winter ◽  
Solar Photovoltaic ◽  
Pv System ◽  
The Impact ◽  
Pv Power Generation

This work attempts to shed some light on the impact of organic soiling due to pollen on solar photovoltaic (PV) power generation. Apart from introducing several soiling-related pollen features, the previous works reporting soiling by pollen have been reviewed. Local observations from late winter to early spring showed that a rooftop PV system experienced both uniform and non-uniform soiling issues, which were mainly caused by pollen from nearby cypress specimens. In addition, this work publishes preliminary results regarding an artificial soiling test performed with pollen. In this test, soda lime float glass coupons were artificially soiled with fresh cypress pollen. A linear relationship was found between the pollen mass density (ρA) and the glass averaged transmittance (TAVE) for values up to 9.1 g/m2. In comparison with other artificial soiling tests performed with different soiling agents, the transmittance loss caused by pollen cypress deposition was relatively high and spectrally selective.

Seeds of Thalictrum mirabile (Ranunculaceae) require cold stratification for loss of nondeep simple morphophysiological dormancy

2000 ◽  
Vol 77 (12) ◽  
pp. 1769-1776 ◽  
Author(s):  
Jeffrey L Walck ◽  
Carol C Baskin ◽  
Jerry M Baskin
Keyword(s):  
Gibberellic Acid ◽  
Seed Bank ◽  
Soil Seed Bank ◽  
Early Spring ◽  
Late Winter ◽  
Cold Stratification ◽  
Morphophysiological Dormancy ◽  
Physiological Dormancy ◽  
Buried Seeds ◽  
Persistent Soil Seed Bank

Seeds of the eastern North American herbaceous polycarpic perennial Thalictrum mirabile Small have differentiated but underdeveloped (small) embryos that are physiologically dormant at maturity in September. Physiological dormancy was broken effectively by cold stratification at 1°C, but embryos required temperatures [Formula: see text]15:6°C for growth after physiological dormancy was broken. Gibberellic acid substituted for cold stratification. Breaking of physiological dormancy in seeds exposed to natural temperatures in a greenhouse occurred during winter, and embryo growth and germination occurred in late winter - early spring. Furthermore, seeds in the greenhouse remained viable until the second and third (spring) germination seasons. Thus, T. mirabile seeds have the capacity to form a short-lived persistent soil seed bank. Buried seeds of T. mirabile apparently go through an annual dormancy-nondormancy cycle. Seeds buried in September 1994 were nondormant when exhumed in April 1995 and April 1996 and incubated in light at 25:15°C for 2 weeks, but they were dormant in June 1995 and September 1995. Seeds of T. mirabile have nondeep simple morphophysiogical dormancy. This is the first report of nondeep simple morphophysiological dormancy being broken by cold, and not by warm, stratification.

scholarly journals A Comparison of Decimeter Scale Variations of Physical and Photobiological Parameters in a Late Winter First-Year Sea Ice in Southwest Greenland

2021 ◽  
Vol 9 (1) ◽  
pp. 60
Author(s):  
Lars Chresten Lund-Hansen ◽  
Clara Marie Petersen ◽  
Dorte Haubjerg Søgaard ◽  
Brian Keith Sorrell
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Biological Properties ◽  
Early Spring ◽  
Small Scale ◽  
Late Winter ◽  
First Year ◽  
Chl A ◽  
Bulk Salinity ◽  
Southwest Greenland

Small-scale variation in the physical and biological properties of sea ice was examined by collecting nine sea ice cores within 1 m2 in a land-fast first-year ice in southwest Greenland in late winter. Cores were sectioned in four segments and sea ice physical, biological, and photobiological parameters were measured. The main purpose was to explore the decimeter-scale horizontal and vertical variations in common sea ice parameters. ANOVA analyses revealed significant within-core variations for bulk salinity, brine salinity, brine volume, gas volume, chlorophyll a (Chl a), and the maximum light-limited photosynthetic efficiency (α). Only temperature and bulk salinity variations were significant between cores, and no significant variations were found within or between cores for other photobiological parameters. Power analyses were applied to determine the number of replicates needed to achieve a significance at p < 0.05 with sufficient power, and showed a minimum of four and preferably five replicate cores to detect the observed variability in this first-year ice. It is emphasized that these results only apply to this type of first-year ice in late winter/early spring, and that different variations may apply to other types of ice.

The long-term impact of nitrogen fertiliser on perennial ryegrass tiller and white clover growing point densities in grazed dairy pastures in south-western Victoria

2002 ◽  
Vol 53 (11) ◽  
pp. 1203 ◽  
Author(s):  
F. R. McKenzie ◽  
J. L. Jacobs ◽  
G. Kearney
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Block Design ◽  
Early Spring ◽  
Late Winter ◽  
Climatic Effects ◽  
Nitrogen Fertiliser ◽  
Point Density ◽  
Long Term Impact ◽  
The Impact

A 3-year grazing experiment determined the impact of multiple applications of different rates of nitrogen (N) fertiliser, applied over autumn and winter in 1997, 1998, and 1999, on perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) tiller and growing point densities (stolon apices with at least 2 nodes). Annual pasture dry matter (DM) yields were also monitored. Four treatments were replicated 3 times in a randomised block design and included: 0 N (A); 3 applications of 25 kg N/ha (B); 3 applications of 50 kg N/ha (C); and 3 applications of 75 kg N/ha (D). Urea (46% N) was the N source. Grazing of treatment plots occurred at a pre-grazing herbage mass of 2200–2500 kg DM/ha.Over 3 years, N applications consistently increased annual pasture DM yields by 0.9–3.3 t/ha when a total of 75–225 kg N/ha was applied annually.Generally, treatments B, C, and D resulted in higher perennial ryegrass tiller densities than treatment A. An exception occurred from July 1998 in Year 2 to July 1999 in Year 3, when all perennial ryegrass densities were similar. Nitrogen fertiliser generally produced no consistent effect on white clover growing point density, with the exception of July–December in Year 2 when treatments B, C, and D resulted in lower growing point densities than treatment A. Clover growing point density decreased over the trial period irrespective of treatment. There were no N fertiliser effects on 'other' grasses and broadleaved weeds. 'Other' grasses (mainly winter grass, Poa annua) did, however, peak in density (up to 2500 tillers/m2) from July to September each year.Seasonally, the peak perennial ryegrass tiller density was similar each year and occurred during late winter–early spring (5450 tillers/m2 in July 1997; 6200 tillers/m2 in August 1998; 5400 tillers/m2 in July 1999). This was followed by a trough over midsummer (800 tillers/m2 in January 1998; 725 tillers/m2 in January 1999). White clover growing point density declined over 3 years. During this decline there were peaks in June 1997 (2650 growing points/m2), November 1997 (1600 growing points/m2), June 1998 (1250 growing points/m2), April 1999 (1050 growing points/m2), and November 1999 (850 growing points/m2). Troughs occurred in January 1998 (530 growing points/m2) and February 1999 (380 growing points/m2).It is concluded that although increasing applications of N increased annual pasture DM yields and generally increased perennial ryegrass tiller densities, with little effect on clover growing point densities, there is little to suggest that N fertiliser alone would enhance the persistence of these pasture species. Persistence is likely to be influenced by a combination of factors including grazing management and climatic effects, rather than N fertiliser alone.

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