The importance of recruitment patterns versus reproductive output in the persistence of a short-range endemic shrub in a highly fragmented landscape of south-western Australia

2012 ◽  
Vol 60 (7) ◽  
pp. 643 ◽  
Author(s):  
Neil Gibson ◽  
Colin Yates ◽  
Margaret Byrne ◽  
Margaret Langley ◽  
Rujiporn Thavornkanlapachai
Keyword(s):  
Short Range ◽  
Reproductive Output ◽  
Fruit Set ◽  
Seedling Recruitment ◽  
Fragment Size ◽  
Fragmented Landscape ◽  
Recruitment Failure ◽  
Degree Of Isolation ◽  
Number Of Seeds ◽  
Significant Mortality

Calothamnus quadrifidus subsp. teretifolius A.S.George & N.Gibson is a short-range endemic shrub whose habitat has been greatly reduced by clearing for agriculture. Reproductive output was high in all populations sampled, although there were large differences among populations in fruit set, the number of seeds per fruit and seed germination. These traits showed no relationship to population size, degree of isolation, or fragment size, which contrasts strongly with the patterns found in a widespread congener. Demographic studies in remnants with an intact understorey showed stable adult populations with continuous seedling recruitment. In contrast, there was consistent widespread failure of seedling and juvenile recruitment in degraded roadside remnants that also showed significant mortality of reproductive adults. In these degraded remnants, recruitment failure appears to be the primary cause of species decline.

scholarly journals SEED PRODUCTIVITY AND DEVELOPMENT OF PLANTLETS POPULUS × JRTYSCHENSIS CH. Y. YANG

2019 ◽  
pp. 51-57
Author(s):  
B. V. Proshkin ◽  
A. V. Klimov
Keyword(s):  
Filter Paper ◽  
Fruit Set ◽  
Control Group ◽  
Natural Hybrid ◽  
Seed Productivity ◽  
Model Trees ◽  
Fruit Number ◽  
Black Poplar ◽  
Petri Dishes ◽  
Number Of Seeds

The research explores the seed productivity and plantlets growth in the free pollination of the natural hybrid taxon P. × jrtyschensis. Fruits of P. × jrtyschensis were selected from four plants that grow in the collection ofResearchCenter“EducationalBotanical Garden” ofKemerovoStateUniversity. Four P. nigra model trees, randomly selected from theTomRiverfloodplain population, were applied as a control group. The authors used 30 fruit-bearing amentumsfrom each model. The researchers measured set of fruit (capsule); number of ovules per fruit; number of seeds per fruit; set of seeds.. Laboratory germination was determined by sowing Petri dishes on wet filter paper. The authors found out sowing germination by sowing 100 seeds in a box with soil and drainage. The energy of germination was determined on the second day while germination - on the fifth day. P. × jrtyschensis is characterized by a lower level of seed productivity (15-30%) compared to P. nigra. In terms of laboratory germination of seeds, the descendants of hybrids surpassed many P. nigra models, but their soil germination was 20-30% lower than that of black poplar. The observed variability in reproductive indices of both P. × jrtyschensis and P. nigra is mainly caused by specific features of their genotypes. Plantlets being developed, the authors observed no significant differences among the descendants of P. nigra and hybrids. The researchers highlighted plantlets that can stop growing and even more abnormal plants with one, three or four seeds in P. × jrtyschensis. This may be caused by underdevelopment of hypocotyl or germ root. The authors observed breaches in development of P. nigra just once. They outline high plantlets destruction when sowing hybrids on the first day after germination The share of destructed plants within a month (from the beginning of the experiment) reaches 66,0 %, and in P. nigra it does not exceed 40,0 %.

Degree of fragmentation and population size do not adversely affect reproductive success of a rare shrub species, Banksia nivea (Proteaceae), in a naturally fragmented community

2019 ◽  
Vol 191 (2) ◽  
pp. 261-273 ◽  
Author(s):  
Rujiporn Thavornkanlapachai ◽  
Margaret Byrne ◽  
Colin J Yates ◽  
Philip G Ladd
Keyword(s):  
Population Size ◽  
Fruit Set ◽  
Medium Size ◽  
Fragmented Landscape ◽  
Pollinator Visitation ◽  
High Germination ◽  
Germination Success ◽  
Landscape System ◽  
Density Population ◽  
Degree Of Fragmentation

Abstract Fragmentation of plant communities is generally considered to be detrimental to the survival of the constituent species, especially those that are rare. We investigated the effects of fragmentation on reproductive biology in nine populations of the rare taxon Banksia nivea subsp. uliginosa, differing in size and habitat context. Small mammals were the main pollinator, with lower contributions from honeybees and birds (honeyeaters). There was no significant relationship between population size, fruit set and seed germinability. Fruit set was marginally highest (25.5 ± 3.4) in medium size populations and was variable over years. Lower fruit set (1.0 ± 0.6) in the smallest population may be due to inbreeding depression or lack of pollinators in a degraded habitat, but low fruit set was also observed in the largest population despite high levels of gene flow, possibly due to low pollinator visitation rate in a low-density population. Seeds from all populations had high germination success (>93.4%). Predation occurred in up to 56% of fruit and increased with increasing population size, but was not significantly different between populations of different size. Our study provided evidence that the reproductive output in species in a naturally fragmented landscape system may be resilient to reduced population size and other influences of anthropogenic fragmentation.

Pollination and Seed Set of Banksia spinulosa: Evidence for Autogamy

1988 ◽  
Vol 36 (6) ◽  
pp. 633 ◽  
Author(s):  
G Vaughton
Keyword(s):  
New England ◽  
Breeding System ◽  
Seed Weight ◽  
National Park ◽  
Fruit Set ◽  
Seed Set ◽  
Pollen Vectors ◽  
Specific Variation ◽  
Number Of Seeds

The breeding system of Banksia spinulosa var. neoanglica in the New England National Park was examined by excluding pollen vectors and hand pollinating inflorescences. Fruit set of xenogamous and open inflorescences was greater than geitonogamous and autogamous treatments, although not all differences were significant. No differences were found in the number of seeds per follicle or seed weight between treatments. A reduced number of follicles and smaller seeds occurred in the apical third of inflorescences in all treatments. This report of autogamous seed set contrasts with previous findings for this species and indicates intra-specific variation in the breeding system.

scholarly journals The influence of habitat conditions on the performance of two invasive, annuals — Impatiens glandulifera and Bidens frondosa

Biologia ◽  
2014 ◽  
Vol 69 (4) ◽  
Author(s):  
Kinga Kostrakiewicz-Gierałt ◽  
Maria Zając
Keyword(s):  
Seedling Recruitment ◽  
Riparian Forest ◽  
Fruit Production ◽  
Spatial And Temporal Variability ◽  
Habitat Conditions ◽  
Impatiens Glandulifera ◽  
Long Distance ◽  
Bidens Frondosa ◽  
Number Of Seeds ◽  
Invasive Annuals

AbstractThe investigations of habitat conditions on the variability of selected population features in the two invasive, annuals with different life-history traits were conducted in the years 2008–2010, in the Polish part of the Carpathian Mountains in communities characterized by the gradual decrease of light availability. The individuals of Impatiens glandulifera were surveyed along roadsides, in willow thickets, as well as inside and along the edges of the riparian forest, whereas the individuals of Bidens frondosa were observed in riverside gravels characterized by a different species composition. Each year, the number and density of individuals (stems) occurring in the particular sites were examined, as well as the height and the fruit production in 30 randomly chosen stems were surveyed. Moreover, the number of seeds per fruit, the diaspore dimensions and the seedling recruitment in laboratory conditions were examined during each season. As the values of height of individuals, number of fruits per stem, number of seeds per fruit, as well as the seedling abundance in some groups were not consistent with the normal distribution and the variances were not homogeneous, the non-parametric Kruskal-Wallis test was used in statistical analyses.Much greater number and density of individuals of Impatiens glandulifera were found in riparian forest, than in willow thickets and along the roadsides. In all sites the number and density of individuals increased steadily in consecutive seasons. The great number and density of Bidens frondosa individuals observed in shady and partly shady sites during the first year of studies raised in the second year and subsequently dramatically decreased in the third season. The lowest number and density of individuals noted in the first season in unshaded site raised substantially in subsequent years. The height of stems, as well as seed and fruit production of both taxa diminished with a decrease of height of neighboring plants. The seed dimensions presented the spatial and temporal variability, whereas the number of seedlings among consecutive years and in successive sites did not differ.The considerable height of the individuals of Impatiens glandulifera, high production of large fruits and seeds in open and dry roadside areas can contribute to more effective ballistic dissemination, while substantial seedling recruitment enables the colonization of new, perhaps more advantageous sites. On the other hand, lower individual height, as well as fruit and seed production and considerable seedling emergence allow the population to last and to gradually extend the area in forest communities. The considerable abundance of the high-statured Bidens frondosa individuals, substantial production of large capitula and achenes contribute to long persistence of populations in open and sun-lit sites. The gradually decrease in the height of the stems, achene number and size observed in partly-shaded and shaded places might allow to long-distance dispersal of seeds by animals, while substantial seedling recruitment might contribute to establishment in new areas.

Influence of panicle fragment size on ant seed-harvesting and seedling recruitment in Phalaris aquatica

2002 ◽  
Vol 42 (5) ◽  
pp. 571 ◽  
Author(s):  
W. M. Kelman ◽  
G. M. Lodge ◽  
R. A. Culvenor
Keyword(s):  
Seedling Recruitment ◽  
Fragment Size ◽  
New South ◽  
New South Wales ◽  
Sheep Grazing ◽  
Phalaris Aquatica ◽  
South Wales ◽  
Naked Seed ◽  
Seed Harvesting ◽  
Second Year

Successful seedling recruitment events in sparse stands of the grass Phalaris aquatica (phalaris) are rare. A major contributing factor to this situation is the seed-harvesting activity of ants. In recently developed cultivars of phalaris, the seed is retained within the glumes of the floret and is shed in a seed-retaining panicle fragment. We tested the hypothesis that seed contained in panicle fragments was less likely to be harvested by ants than naked seed and that this would be reflected in increased seedling recruitment. Observations of ant seed-harvesting activity and records of seedling recruitment following dispersal of seed and panicle fragments onto field plots were made at Canberra, Australian Capital Territory, and Tamworth, New South Wales, over 2 years. In the second year, the effects of 2 pasture renovation treatments (sheep-grazing and shallow-discing) on seedling recruitment from seed and panicle fragments were examined. Averaged over the 2 localities, 4% of large-sized (>10�florets), 13% of medium-sized (5-10 florets) and 27% of the small-sized (2 or 3 florets) panicle fragments were harvested in a 24 h period by ants (mainly Pheidole spp.), compared with 83% of the naked phalaris seed. The effects of panicle fragment size on recruitment were variable depending on site in the first year and the interaction of site and renovation treatments in the second year, but contrary to expectation, recruitment often was not higher in panicle fragment treatments than in seeded treatments. Seedling recruitment at Canberra (a hardsetting sandy loam) was lower (22 plants/m2 from naked seed and 15 plants/m2 from seed in panicle fragments) because of the competition from existing vegetation and germination of subterranean clover from the seedbank, than at Tamworth (a self-mulching red chromosol; 179 plants/m2 from naked seed and 118 plants/m2 from seed in panicle fragments), where seedling recruitment was also significantly increased by the sheep-grazing renovation treatment. At Tamworth, a larger seedbank was recovered from plots of oversown panicle fragments compared with plots oversown with naked phalaris seed. This suggested that protection of seeds in panicle fragments over the summer months on the Tablelands of New South Wales would increase the time over which phalaris seeds are available for recruitment. Further work is needed to test seedling recruitment in panicle shattering v. non-shattering phalaris populations and to define the conditions under which the seedbank contained in the panicle fragments can be exploited to improve stand persistence.

Breeding System and Tests for Pollen-Limitation in Two Species of Banksia

1990 ◽  
Vol 38 (1) ◽  
pp. 63 ◽  
Author(s):  
RL Goldingay ◽  
RJ Whelan
Keyword(s):  
Breeding System ◽  
Reproductive Output ◽  
Fruit Set ◽  
Pollen Limitation ◽  
Floral Display ◽  
Cross Pollination ◽  
Self Pollination

Three factors that potentially influence fruit set (breeding system, inadequate cross-pollination and variable floral display) were examined for two species of Banksia. Firstly, self-pollination and autogamy treatments failed to produce any fruit in B. spinulosa and produced very few fruit in B. paludosa. This suggests that cross pollen is required to produce the level of fruit set observed in the field. Secondly, when plants were given abundant cross pollen, fruit set was not altered in B. spinulosa but was in B. paludosa. Although the number of follicles per inflorescence was was not different for open- pollinated (control) and manipulated B. paludosa inflorescences, the latter produced twice the proportion of inflorescences with follicles produced by control plants and twice the total number of follicles per plant. Thirdly, larger floral display in open-pollinated B. spinulosa plants was associated with a greater production of fruit. However, larger floral display was not associated with a greater reproductive output in B. paludosa, and we suggest that recurrent pollen-limitation in this species may be responsible for this result.

scholarly journals Interspecific and Intraspecific Pollination Effects in Rabbiteye and Southern Highbush Blueberry

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 324-326 ◽  
Author(s):  
Creighton L. Gupton ◽  
James M. Spiers
Keyword(s):  
Fruit Development ◽  
Fruit Set ◽  
Highbush Blueberry ◽  
Blue Ridge ◽  
Vaccinium Ashei ◽  
Berry Weight ◽  
Cape Fear ◽  
Southern Highbush ◽  
Number Of Seeds ◽  
Partial Diallel

To determine the effects of pollen source on blueberry production, we made a partial diallel set of crosses involving seven rabbiteye (Vaccinium ashei Reade) and seven southern highbush (SH; V. corymbosum L.) parents. Pollination of rabbiteye blueberry flowers with SH pollen reduced fruit set, seeds per berry, and berry weight and increased fruit development period (FDP) compared to pollination with rabbiteye pollen. Pollination of SH flowers with rabbiteye pollen resulted in about the same fruit set and FDP but fewer seeds per berry and slightly lower berry weight compared to intraspecific pollination. Self-pollination significantly decreased the number of seeds per berry and berry weight and increased FDP in SH. Pollination of rabbiteye and SH flowers with mixed pollen produced the same results as intraspecific pollination. Using `Tifblue' and `Baldwin' (rabbiteye) as the pollen parent significantly increased FDP in rabbiteye blueberry. Using `Georgiagem' and `Cape Fear' as pollen parents produced the longest FDP, and using `O'Neal' and `Gulfcoast' produced the shortest FDP in SH blueberry. The heaviest berries were produced by using `Blue Ridge', `O'Neal', and `Gulfcoast' (SH) as pollen parents on SH females. These results suggest that xenia possibly could be used to increase yield and reduce FDP in blueberry.

scholarly journals Experimental food supplementation increases reproductive effort in an antbird in subtropical Brazilian Atlantic Forest fragments

2014 ◽  
Author(s):  
James J Roper ◽  
André M. X. Lima ◽  
Angélica M. K. Uejima
Keyword(s):  
Food Availability ◽  
Reproductive Effort ◽  
Fragment Size ◽  
Food Limitation ◽  
Survival Rates ◽  
Food Supplementation ◽  
Fragmented Landscape ◽  
Forest Fragments ◽  
Daily Nest Survival ◽  
Nesting Patterns

Food limitation may interact with nest predation and influence nesting patterns, such as breeding season length and renesting intervals. If so, reproductive effort should change with food availability. Thus, when food is limited, birds should have fewer attempts and shorter seasons than when food is not limiting. Here we experimentally test that increased food availability results in increased reproductive effort in a fragmented landscape in the Variable Antshrike (Thamnophilus caerulescens) in southern Brazil. We followed nesting pairs in five natural fragments (4, 23, 24, 112, 214 ha) in which food was supplemented for half of those pairs, beginning with the first nest. Nest success in the largest (214 ha) fragment was 59%, compared to 5% in the 112 ha fragment and no nest was successful in the smallest (24 ha) fragment. Birds were seen, but evidence of nesting was never found in the two smallest fragments. Pairs with supplemented food were more likely to increase clutch size from two to three eggs, tended to renest sooner (20 d on average) than control pairs. Also, fragment size interacted with breeding and pairs in the largest fragment had greater daily nest survival rates, and so nests tended to last longer, and so these pairs had fewer nesting attempts than those in the 112 ha fragment while more than those in the smallest fragment with nesting (24 ha). Clearly, pairs increased their reproductive effort when food was supplemented in comparison to control pairs and fragment size seems to influence both predation risk and food abundance.

scholarly journals The Effective Pollination Period in Rabbiteye Blueberry

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 825A-825
Author(s):  
Patricio A. Brevis* ◽  
D. Scott NeSmith
Keyword(s):  
Fruit Set ◽  
Field Performance ◽  
Fruit Crops ◽  
Vaccinium Ashei ◽  
Berry Weight ◽  
Flower Age ◽  
The Difference ◽  
Days After Anthesis ◽  
Number Of Seeds ◽  
Commercial Field

Rabbiteye blueberries (Vaccinium ashei Reade) often exhibit poor fruit set under commercial field conditions. Problems of low fruit set have been attributed to short periods of flower receptivity in different fruit crops. This study seeks to establish the effective pollination period (EPP, defined as the number of days during which pollination is effective to produce a fruit) in rabbiteye blueberry. The cultivars Brightwell and Tifblue were chosen due to their known difference in fruit set and field performance. Flowers were hand pollinated 0, 2, 4, 6, and 8 days after anthesis (DAA) using self- and cross-pollen. Fruit set, seeds per berry, berry weight and days to ripening were recorded. Fruit set showed a polynomial trend across flower ages. `Brightwell' was highly receptive from the day of anthesis, whereas, `Tifblue' receptivity was low until 2 DAA. `Brightwell' and `Tifblue' flowers produced adequate fruit set (≥50%) over a period of 7 and 5 days, respectively. In `Tifblue', fruit set was limited by the low receptivity of newly opened flowers. The difference in EPP helps to explain the performance of these cultivars in the field. The rate of ripening increased with flower age in both cultivars. The number of seeds per berry was affected by flower age only in `Tifblue'. The effect of flower age on berry weight depended on the cultivar and the pollen source.

scholarly journals Effect of Boron and Calcium Foliar Sprays on Pollen Germination and Development, Fruit Set, Seed Development, and Berry Yield and Quality in Lowbush Blueberry (Vaccinium angustifolium Ait.)

1998 ◽  
Vol 123 (4) ◽  
pp. 524-531 ◽  
Author(s):  
Youzhi Chen ◽  
John M. Smagula ◽  
Walter Litten ◽  
Scott Dunham
Keyword(s):  
Pollen Germination ◽  
Fruit Set ◽  
Yield Reduction ◽  
Vaccinium Angustifolium ◽  
Foliar Sprays ◽  
Lowbush Blueberry ◽  
Berry Size ◽  
Number Of Seeds

In a managed field of native Vaccinium angustifolium Ait. clones, the effect of fall foliar sprays of B at 345 g·ha-1 and/or Ca at 3,450 g·ha-1 in remedying tissue deficiency of B varied among 12 clones, as seen in pollen germinability and on individual stems as seen in flower number, fruit set, and number of harvestable berries. With Ca applied alone, increased berry size did not overcome yield reduction due to fewer flowers and berries per stem. Berry diameter and mass correlated better to number of seeds of germinable size than to total number of seeds. Pollen germination averaged 17.4% on stigmata from untreated clones, and all three treatments (B, Ca, B + Ca) increased that average by 8%. More seeds per berry with the B-alone treatment implies more ovules fertilized when B deficiency is remedied. No relation was found between in vitro and in vivo pollen germination.

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