Biotic and abiotic drivers of dipterocarp seedling survival following mast fruiting in Malaysian Borneo

2014 ◽  
Vol 31 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Chiaki Oshima ◽  
Yuji Tokumoto ◽  
Michiko Nakagawa
Keyword(s):  
Survival Data ◽  
Species Coexistence ◽  
Seedling Survival ◽  
Abiotic Factors ◽  
Canopy Openness ◽  
Relative Importance ◽  
Tropical Rain Forests ◽  
Seedling Density ◽  
Mast Fruiting ◽  
General Flowering

Abstract:South-East Asian tropical rain forests experience sporadic, but profuse, seed production after general flowering, leading to the synchronous emergence of various seedlings and subsequent seedling dynamics, which play a crucial role in determining species distribution and coexistence. We examined the relative importance of both biotic (initial height, conspecific seedling density) and abiotic (canopy openness, per cent sand, soil water content) drivers using survival data for 1842 seedlings of 12 dipterocarp species for 1.5 y following mast fruiting in an old-growth Bornean tropical rain forest. More than 30% of all dipterocarp seedlings survived 1.5 y after mast fruiting. When all species were analysed together, we found that initial seedling height, canopy openness and conspecific seedling density affected dipterocarp seedling survival. Negative density dependence indicated that predators were not satiated, but dipterocarp seedlings rather suffered from host-specific natural enemies or intraspecific competition. Species-level analyses of seven dipterocarp species showed large variation in response to biotic and abiotic factors. These results suggest that interspecific differences in the relative importance of biotic and abiotic effects on seedling survival might contribute to species coexistence.

Do dipterocarp seedlings really partition tropical rain forest gaps?

1992 ◽  
Vol 335 (1275) ◽  
pp. 369-378 ◽  
Keyword(s):  
Rain Forest ◽  
Seedling Survival ◽  
Canopy Gaps ◽  
Forest Recovery ◽  
Canopy Openness ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Regeneration Dynamics ◽  
Closed Forest ◽  
Survival And Growth

The theory of gap regeneration dynamics proposes that different species of tree partition canopy gaps because they are preferentially adapted to a particular gap size class. A variety of gap sizes would therefore favour the regeneration of a range of species. The theory has been used to explain the extraordinarily high tree species diversity of tropical rain forests. A test was mounted in lowland evergreen dipterocarp rain forest in the Danum Valley, Sabah, East Malaysia by the creation of ten, artificial canopy gaps ranging in size from 10 m 2 to 1500 m 2 (6 to 30% canopy openness). The responses of established populations of seedlings of three dipterocarp species ( Hopea nervosa , Parashorea malaanonan and Shorea johorensis ) with contrasting silvicultural reputations were monitored for 40 months in these gaps and under closed forest. There were significant differences in survival and growth under closed forest between these three species. However, in gaps, the most important determinant of seedling survival and growth was seedling size at the time of gap creation, regardless of species. An ability to persist for long periods under closed forest and slowly accumulate growth may bestow an enormous size advantage on seedlings when gaps occur. Generalizations on the regeneration dynamics of dipterocarp rain forests need to be modified in the light of this result. Further observations for several years are important to see whether forest recovery eventually converges on predictions from the original paradigm.

scholarly journals Dynamics of Abies Nephrolepis Seedlings in Relation to Environmental Factors in Seorak Mountain, South Korea

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 702
Author(s):  
Kim ◽  
Lim ◽  
Yun
Keyword(s):  
Species Richness ◽  
Environmental Factors ◽  
Abiotic Factors ◽  
Negative Relationship ◽  
Basal Area ◽  
Ecosystem Dynamics ◽  
Environmental Drivers ◽  
Canopy Openness ◽  
Seedling Density ◽  
Rock Exposure

We present novel evidence of environmental drivers of seedling density in Abies nephrolepis, an alpine and subalpine tree species. Continuous monitoring of natural conditions is required to understand forest ecosystem dynamics. We investigated Abies nephrolepis seedling dynamics in relation to biotic and abiotic factors. The survey, which included the measurement of trees and seedlings, was carried out from March to October in 2016 and 2018. Monitoring sites in the coniferous forests of Seorak Mountain were divided into 27 quadrats. We analyzed relationships using simple and multiple linear regression. The majority of Abies nephrolepis individuals had a diameter at breast height less than l0 cm, and the number of seedlings increased over the study period. This reflects survival and growth due to successive annual mast seeding events. Aspect direction (R2 = 0.201, p < 0.05), rock exposure (R2 = 0.364, p < 0.001), canopy openness (R2 = 0.322, p < 0.05), herbaceous cover (R2 = 0.268, p < 0.01), and basal area (R2 = 0.199, p < 0.05) show significant linear relationships with seedling density. Seedling density was positively related to rock exposure, canopy openness, and species richness, and there was a negative relationship between herbaceous cover and basal area (p < 0.0001). The relative importance of predictor variables was as follows: Rock exposure (40.3%), canopy openness (30.2%), basal area (13.9%), herbaceous cover (11.5%), and species richness (4.1%). Seedling density was most strongly influenced by the presence of large rocks, which provide shelter from harsh winds and a substrate for moss. We conclude that appropriate canopy openness creates a synergistic relationship. We found a positive association between the Abies nephrolepis seedling density in subalpine forests and certain physical environmental factors. Therefore, environmental gradients about the roles of rocks and canopies apply, even in this habitat.

scholarly journals Carbohydrates on the growth of Cattleya schilleriana Reichb.f. seedlings (Orchidaceae)

2018 ◽  
Vol 48 (7) ◽  
Author(s):  
Renato Fernandes Galdiano Júnior ◽  
Cibele Mantovani ◽  
Eliana Gertrudes de Macedo Lemos
Keyword(s):  
Survival Data ◽  
Culture Medium ◽  
Seedling Survival ◽  
In Vitro Growth ◽  
Growth Data ◽  
Carbohydrate Source ◽  
Carbohydrate Supplementation ◽  
Percentage Survival ◽  
Half Strength

ABSTRACT: The aim of the present study was to evaluate the effects of carbohydrate supplementation on the propagation of the orchid Cattleya schilleriana. The 120-d-old seedlings were subcultured in fructose-, glucose-, or sucrose-supplemented (0, 15, 30, and 45g L-1) ½ MS culture medium (half-strength macronutrient concentrations), using a completely random design with four repetitions per treatment. After 120d of treatment, root number and length, leaf number and length, and fresh weight were evaluated, and seedling survival was evaluated after 75d of acclimatization in a greenhouse. The in vitro growth data were submitted to regression analysis, whereas the percentage survival data were analyzed using ANOVA and Tukey’s test. Both in vitro growth and ex vitro survival were lowest when the plantlets were grown in the absence of a carbohydrate source and highest (>90% survival) when supplemented with glucose. According to our findings, the addition of either glucose (30g L-1) or sucrose (30g L-1) is recommended for mass propagation of C. schilleriana.

The relative importance of biotic and abiotic factors influencing aspen recruitment in Arizona

2019 ◽  
Vol 441 ◽  
pp. 32-41 ◽  
Author(s):  
Matthew J. Clement ◽  
Larisa E. Harding ◽  
Richard W. Lucas ◽  
Esther S. Rubin
Keyword(s):  
Abiotic Factors ◽  
Relative Importance ◽  
Biotic And Abiotic Factors ◽  
Factors Influencing

Preemergence Control of Spotted Spurge (Chamaesyce maculata) with Flumioxazin as Influenced by Formulation and Activation Moisture

2015 ◽  
Vol 29 (1) ◽  
pp. 108-114 ◽  
Author(s):  
Glenn Wehtje ◽  
Q. Yang ◽  
Charles H. Gilliam ◽  
Anna-Marie Murphy ◽  
Jason Fausey
Keyword(s):  
Survival Data ◽  
Seedling Survival ◽  
Separation Distance ◽  
Irrigation Level ◽  
Time Of Application ◽  
Nursery Production ◽  
Excellent Control ◽  
Substrate Moisture ◽  
The Relationship ◽  
Maximum Separation

Flumioxazin is commonly used in nursery production for PRE weed control. Container nursery producers are of the opinion that the granular formulation is less effective than the sprayable formulation. Under the hypothesis that the granular formulation may require more water for activation, an experiment was conducted to evaluate the interaction of flumioxazin formulation, rate, and activation moisture for PRE control of spotted spurge in a pine-bark substrate. Experiment consisted of a factorial arrangement of four experimental variables; flumioxazin formulation (granular and spray), and flumioxazin rate (0.28 and 0.42 kg ai ha−1), substrate moisture level at the time of application (dry, medium, and wet), and after-application irrigation level (a single irrigation at 0.6, 1.3, 2.5, and 5.1 cm). Treated pots were seeded with spotted spurge 2 d after the herbicide application, which was 1 d after the first irrigation. Control as indicated by spotted spurge counts and fresh weight was influenced only by flumioxazin rate and formulation. The sprayable formulation provided excellent control regardless of rate. Granular formulation was generally less effective, and additional activation moisture did not improve efficacy. Further studies were conducted with the granular formulation to determine the maximum separation distance between the spotted spurge seed and herbicide prills at which control is possible. Individual prills and spotted spurge seeds were placed on media surface at progressively increasing separation distances. Nonlinear regression of seedling survival data revealed that ≥99% control required a prill–seed separation of ≤5.2 mm. This prill–seed separation requirement is only marginally obtained with the current registered rate, i.e., 0.42 kg ai ha−1 or 168 kg product ha−1. The relationship between control and prill–seed separation distance cannot be manipulated by additional activation moisture. Inadequate contact between the spotted spurge seeds and the flumoioxazin-containing prills is likely the sole cause of inadequate control.

Seedling emergence and survival of Warea carteri (Brassicaceae), an endangered annual herb of the Florida Scrub

2007 ◽  
Vol 85 (7) ◽  
pp. 621-628 ◽  
Author(s):  
Carl W. Weekley ◽  
Eric S. Menges ◽  
Pedro F. Quintana-Ascencio
Keyword(s):  
Seedling Survival ◽  
Seedling Emergence ◽  
Annual Plants ◽  
Seedling Density ◽  
Florida Scrub ◽  
Seedling Emergence And Survival ◽  
History Of ◽  
Annual Herb ◽  
Winter Annual ◽  
Persistent Seed Bank

Seedling emergence and survival to flowering are critical processes in the life history of annual plants. We evaluated the importance of year and habitat on seedling emergence and the effects of year, habitat, timing of seedling emergence, and seedling density on survival of Warea carteri Small, an annual mustard endemic to Florida scrub. We tagged 1329 seedlings in 78 permanent 0.25 m2 quadrats in two habitats (scrub and disturbed) between 1999 and 2002 and followed seedlings monthly. Most (>80%) seedling emergence occurred between September and December. Emergence peaked 2 months earlier and was more variable in disturbed sites than in scrub. Seedling survival among years ranged from 3.5% to 12.0%. Seedling density varied from 1 to 75 per 0.25 m2 quadrat, with an overall median of 6.0. Survival was not density dependent. Median age at flowering ranged from 11.7 to 15.2 months, with late season recruits most likely to survive to flowering. Warea carteri recruits like a winter annual but flowers like a summer annual. Its delayed germination and a 12–15 month life span contribute to population cycling. Complete reproductive failure in unfavorable years, high seed production in favorable years, low rates of seed germination, and a persistent seed bank are consistent with predictions for an annual species in a variable habitat.

The effects of a hurricane on seedling dynamics and abiotic interactions in a tropical lower montane wet forest

2013 ◽  
Vol 30 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Denneko Luke ◽  
Kurt McLaren ◽  
Byron Wilson
Keyword(s):  
Common Species ◽  
Relative Importance ◽  
Seedling Density ◽  
Negative Effects ◽  
Lower Growth ◽  
Permanent Sample Plots ◽  
Seedling Dynamics ◽  
Before And After ◽  
Abiotic Interactions ◽  
Periodic Changes

Abstract:We assessed seedling dynamics and understorey light before and after a hurricane in five randomly selected 5 × 5-m subplots, within 30 permanent sample plots covering a total area of 3750 m2 in a lower montane wet tropical forest, Jamaica over a period of 3 y. Understorey light increased (≈ 60%) following the passage of Hurricane Dean in 2007 but decreased in 2009. Overall, seedling density was positively related to light and survivorship was positively related to both light and density. Mortality was significantly lower and most species recorded their highest growth when the canopy was open (2007–2008). However, lower diversity during this period coincided with higher (average) mortality of uncommon species. The hurricane altered the relative importance of interactions between light, seedling density and dynamics. Consequently, interactions were significant before or 2 y after but not 1 y after the hurricane and their significance varied among the years and species. Periodic changes in the importance of these interactions and the effects of the hurricane were used to separate 12 common species along a continuum of responses, which ranged from positive (lower mortality), neutral to negative (lower growth). Our results indicate that hurricanes have positive and negative effects on seedling dynamics; therefore an increase in the intensity and frequency of hurricanes will likely alter seedling composition, and hence forest structure.

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