scholarly journals Size-Dependent Patterns of Seed Rain in Gaps in Temperate Secondary Forests, Northeast China

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 123 ◽  
Author(s):  
Qiaoling Yan ◽  
Qun Gang ◽  
Jiaojun Zhu

Secondary forests have become the major forest type worldwide, and are experiencing various disturbances and exhibiting obvious vegetation degradation (e.g., reduced biodiversity and decreased productivity) compared with primary forests. Forest gap is a common small-scale disturbance in secondary forests. Promoting natural regeneration under gap disturbance is an important approach to recover biodiversity and ecosystem services for temperate secondary forests. The gap size is the crucial characteristic controlling natural regeneration of many tree species. However, little is known about the spatiotemporal pattern of seed rain for gravity-dispersed and wind-dispersed tree species in gaps of varying sizes. The objectives of this study were to determine how seed rain of dominant tree species depend on gap size, and consequently, to explore some gap-based silviculture solutions for restoring secondary forests from the view of seed dispersal. The spatial distribution of seed rain in gaps with three sizes (large gaps of 250–350 m2, medium gaps of 150–250 m2, and small gaps of < 150 m2), the temporal dynamics of seed rain over three years, and the relationship between seed rain and soil seed banks were explored in temperate secondary forests. The results showed that more than 90% of the seeds in seed rain were wind-dispersed, and their seed rain density and the contribution of seed rain to soil seed bank in medium gaps reached the highest (p = 0.03). The results suggest that establishing medium-sized gaps (i.e., gap size with 150–250 m2) in the secondary forests is more favorable for improving the natural regeneration potential (arrival of seeds and forming soil seed bank) of gap-dependent and wind-dispersed species (e.g., Acer mono) in gaps.

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 500
Author(s):  
Zong Zhao ◽  
Yong Liu ◽  
Hongyan Jia ◽  
Wensheng Sun ◽  
Angang Ming ◽  
...  

Objective: To investigate the impact of different slope directions on the quantity and quality of the soil seed bank and seedling germination process of Castanopsis hystrix plantations. Method: Fixed sample plots in forest stands of Castanopsis hystrix were established on different slope directions (sunny slope, semi-sunny slope, semi-shady slope, and shady slope). The characteristics of the forest stand were investigated, and per-wood scaling was carried out. The temporal dynamics of the seed rain and seed bank were quantified using seed rain collectors and by collecting soil samples from different depths. The quantity and quality of the seeds were determined, and the vigor of mature seeds was measured throughout the study. Results: (1) The diffusion of Castanopsis hystrix seed rain started in mid-September, reached its peak from late October to early November, and ended in mid-December. (2) The dissemination process, occurrence time, and composition of the seed rain varied between the different slope directions. The seed rain intensity on the semi-sunny slope was the highest (572.75 ± 9.50 grains∙m−2), followed by the sunny slope (515.60 ± 10.28 grains∙m−2), the semi-shady slope (382.13 ± 12.11 grains∙m−2), and finally the shady slope (208.00 ± 11.35 grains∙m−2). The seed rain on the sunny slope diffused earliest and lasted the longest, while the seed rain on the shady slope diffused latest and lasted the shortest time. Seed vigor and the proportion of mature seeds within the seed rain were greatest on the semi-sunny slope, followed by the sunny slope, semi-shady slope, and the shady slope. (3) From the end of the seed rain to August of the following year, the amount of total reserves of the soil seed banks was highest on the semi-sunny slope, followed by the sunny slope then the semi-shady slope, and it was the lowest on the shady slope. The amount of mature, immature, gnawed seeds and seed vigor of the soil seed bank in various slope directions showed a decreasing trend with time. The seeds of the seed bank in all slope directions were mainly distributed in the litter layer, followed by the 0–2 cm humus layer, and only a few seeds were present in the 2–5 cm soil layer. (4) The seedling density of Castanopsis hystrix differed significantly on the different slope directions. The semi-sunny slope had the most seedlings, followed by the sunny slope, semi-shady slope, and the shady slope. Conclusions: The environmental conditions of the semi-sunny slope were found to be most suitable for the seed germination and seedling growth of Castanopsis hystrix, and more conducive to the regeneration and restoration of its population.


Plants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1391
Author(s):  
Anussara Chalermsri ◽  
La-aw Ampornpan ◽  
Witoon Purahong

Human activity negatively affects the sustainability of forest ecosystems globally. Disturbed forests may or may not recover by themselves in a certain period of time. However, it is still unclear as to what parameters can be used to reasonably predict the potential for self-recovery of human-disturbed forests. Here, we combined seed rain, soil seed bank, and seed emergence experiments to evaluate the potential for self-recovery of a highly disturbed, tropical, mixed deciduous forest in northeastern Thailand. Our results show a limited potential for self-recovery of this forest due to low seedling input and storage and an extremely high mortality rate during the drought period. There were 15 tree species of seedlings present during the regeneration period in comparison with a total number of 56 tree species in current standing vegetation. During the dry season, only four tree seedling species survived, and the highest mortality rate reached 83.87%. We also found that the correspondence between the combined number of species and composition of plant communities obtained from seed rain, soil seed bank, and seedling emergence experiments and the standing vegetation was poor. We clearly show the temporal dynamics of the seed rain and seedling communities, which are driven by different plant reproductive phenology and dispersal mechanisms, and drought coupled with mortality. We conclude that this highly disturbed forest needs a management plan and could not recover by itself in a short period of time. We recommend the use of external seed and seedling supplies and the maintenance of soil water content (i.e., shading) during periods of drought in order to help increase seedling abundances and species richness, and to reduce the mortality rate.


1993 ◽  
Vol 71 (3) ◽  
pp. 471-485 ◽  
Author(s):  
Jeanne C. Chambers

Relationships among the aboveground vegetation, seed rain, and seed bank were examined on a late seral herb field characterized by pocket gopher disturbance and on an early seral gravel borrow that had been severely disturbed 35 years ago on the Beartooth Plateau, Montana. Aboveground vegetation cover was assessed by species in twelve 5-m2 plots. Seed rain was sampled during the 1988, 1989, and 1990 growing seasons with pitfall traps, and the soil seed bank was sampled in fall 1989, spring 1990, and fall 1990. The seed rain (filled seeds) on the borrow area ranged from 7730 to 14 009 seeds/m2 and was higher than that found on other alpine sites; that on the Geum turf ranged from 3375 to 6179 seeds/m2 and was similar to that for other alpine sites. Although highly variable among dates on the borrow area, the seed banks were similar to those of comparable alpine sites. Seed bank density ranged from 1980 to 6003 seeds/m2 on the borrow area and from 3202 to 4647 seeds/m2 on the Geum turf area. The Geum turf area had higher vegetation cover than the borrow area (87 vs. 25%) and higher numbers of species in the aboveground vegetation, seed rain, and seed bank. Relationships among the aboveground vegetation, seed rain, and seed bank were largely determined by the disturbance characteristics of the different sites and the life-history strategies of the dominant species. Medium-lived species, primarily grasses, with high production of small and compact seeds had colonized the borrow area. Despite establishment of other species, 35 years after disturbance the medium-lived species still dominated the aboveground vegetation, seed rain, and seed bank. Species abundances in the three different components were all highly correlated. In contrast, on the Geum turf area there were no correlations among the aboveground vegetation, seed rain, or seed bank. Long-lived forbs that produced low numbers of relatively large seeds dominated the aboveground vegetation and persisted on the area primarily in the vegetative state. The same medium-lived species that dominated the borrow area had the highest abundance in the seed rain on the Geum turf area and appeared to persist by colonizing small-scale disturbances caused by gopher burrowing. Short-lived species with small, long-lived seeds existed on the site primarily through a highly persistent seed bank. The relationships among the aboveground vegetation, seed rain, and seed bank on the Geum turf and borrow areas are compared with those observed for more temperate systems following disturbance. Key words: alpine, herb field, Geum turf, disturbance, vegetation cover, seed rain, seed bank, colonization, establishment, succession.


2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abdullah Al Mamun ◽  
Mohammed Kamal Hossain ◽  
Md. Akhter Hossain

PurposeIn this paper, the authors show that ecological restoration potential through natural regeneration of degraded tropical rainforest is possible. This is significant because at present most of the tropical forest of the world, including of Bangladesh, are degraded.Design/methodology/approachRegeneration status of Chunati Wildlife Sanctuary (CWS) was assessed through stratified random sampling method using sample plots of 5 × 5 m in size covering 269 sample plots.FindingsA total of 3,256 regenerating seedlings/saplings of 105 species belonging to 35 families were recorded from CWS. From regenerating tree species, maximum (37.83) family importance value (FIV) index was found for Euphorbiaceae followed by Myrtaceae (18.03). Maximum importance value index (IVI) was found for Aporosa wallichii (21.62) followed by Grewia nervosa (16.41). Distribution of seedlings into different height classes of regenerating tree species was also calculated.Practical implicationsForest scientists are working to find out the best nature-based solution for ecological restoration of tropical rainforests to attain climate resilient ecosystem in a sustainable way. Tropical rain forest has huge plant diversity, and we find that ecological restoration is possible through natural regeneration from its rich soil seed bank. Natural regeneration is the best nature-based solution for sustainable management of the forest.Social implicationsThe authors believe that the findings presented in our paper will appeal to the forest and environmental scientists. The findings will allow readers to understand degraded tropical hill forest ecosystem and its management strategy.Originality/value The authors believe that this manuscript will give a clear picture about degraded tropical hill forest ecosystem and its genetic composition, diversity and soil seed bank status to apply appropriate management strategy.


Ecoscience ◽  
2002 ◽  
Vol 9 (3) ◽  
pp. 407-413 ◽  
Author(s):  
Christopher J. Lortie ◽  
Roy Turkington

2020 ◽  
Vol 13 (3) ◽  
pp. 256-265 ◽  
Author(s):  
José Djalma de Souza ◽  
Bruno Ayron de Souza Aguiar ◽  
Danielle Melo dos Santos ◽  
Vanessa Kelly Rodrigues de Araujo ◽  
Júlia Arruda Simões ◽  
...  

Abstract Aims In dry tropical forests, herbaceous species may have dormancy mechanisms and form persistent and transient seed banks in the soil. Evolutionarily acquired, these mechanisms are efficient for the establishment and survival of these herbs, especially in forests with unpredictable climates, such as the Caatinga. Thus, our objective was to verify whether the studied herbaceous species adopt the physical dormancy mechanism and how these natural barriers are overcome, to understand the temporal dynamics existing in the soil seed bank from a Brazilian dry tropical forest. Methods Seeds of five native herbaceous species from the Caatinga forests were selected and submitted to pre-germinative treatments for verifying the presence of physical dormancy. We collected soil samples in the rainy and dry seasons for four consecutive years and monitored the emergence of the selected herbaceous in the greenhouse. We verified the differences in germination and seed bank emergence in the soil by generalized linear models. Important Findings The presence and absence of physical dormancy were observed in seeds from Caatinga herbaceous species. We found intraspecific and interspecific differences in the herbaceous emergence from soil seed banks between years and climatic seasons. In perennial herbs, consecutive lack of emergence between seasons and years was frequent, which suggests a direct relationship with the mechanism of physical dormancy and the environmental conditions necessary to overcome integument barriers. In these species, seed dimorphism and dormancy may confer additional advantages to their survival. Moreover, presenting intermediate levels of physical dormancy in an annual species may be an evolutionary adjustment to rainfall unpredictability. In contrast, we found that the annual herb without dormancy is more sensitive to seasonal and interannual climate changes, as evidenced by the increase and significant reduction of its emergence in the soil seed bank. These differences acquired evolutionarily are advantageous for the establishment of herbaceous populations, mainly in semiarid regions with an unpredictable climate.


2020 ◽  
Vol 13 (4) ◽  
pp. 489-498
Author(s):  
Wenting Liu ◽  
Shixian Sun ◽  
Chunping Zhang ◽  
Shijie Lv ◽  
Quanmin Dong

Abstract Aims Ecological strategies related to the adaptation of plants to environmental stress have long been studied by ecologists, but few studies have systematically revealed the ecological process of plant adaptation to herbivores as a whole. Methods In this study, Stipa breviflora, the dominant species in the desert steppe of Inner Mongolia, was used to analyse its reproductive individual characteristics and seed traits as well as the soil seed bank and spatial patterns under heavy-grazing and no-grazing treatments. Important Findings The results showed that the number of reproductive branches positively affected the number of vegetative branches. The analysis of the soil seed bank showed that the density of S. breviflora seeds beneath reproductive S. breviflora individuals was significantly higher than that in bare land. The seed density was also significantly negatively correlated with the seed characteristics and the soil seed bank in bare land. The spatial distribution of S. breviflora was aggregated under heavy grazing. Our results suggest that under heavy grazing, reproductive activity plays a key role in resource allocation. Stipa breviflora evolved the ecological strategy of nearby diffusion by regulating the morphological characteristics of the seeds, which promotes a positive spatial correlation between the juvenile and adult populations at a small scale, thus leading to the formation of ‘safe islands’.


FLORESTA ◽  
2011 ◽  
Vol 41 (2) ◽  
Author(s):  
Marcelo Lima de Souza ◽  
Antônio Carlos Nogueira ◽  
Renato Luiz Grisi Macedo ◽  
Carlos Roberto Sanquetta ◽  
Nelson Venturin

O objetivo do presente trabalho foi estudar o banco de sementes no solo de um fragmento florestal com Araucaria angustifolia (Bert.) O. Ktze. no estado do Paraná. Para isso, investigou-se a distribuição vertical das sementes, a influência do sombreamento sobre a emergência das plântulas, sua identificação e quantificação. A distribuição vertical de sementes em quatro camadas foi analisada através da identificação e quantificação das plântulas emergentes em casa de vegetação, levando em consideração o nível de sombreamento. Os dados referentes ao banco de sementes foram obtidos no período de 210 dias, por meio de identificação botânica e contagens semanais das plântulas germinadas das quatro profundidades de solo em quatro parcelas experimentais. As amostras foram colocadas para germinar sob 0 e 50% de sombreamento em casa de vegetação. Os resultados obtidos no estudo de banco de sementes permitiram as seguintes conclusões: o banco de sementes parece ser pobre em espécies arbóreas e abundante em espécies herbáceas; o banco de sementes das espécies arbóreas foi maior na segunda camada; ocorreu maior germinação sob 0% de sombreamento. Provavelmente, a estratégia de regeneração da maioria das espécies presentes nessa área de estudo parece não ser pelo banco de sementes no solo.Palavras-chave: Banco de sementes no solo; Araucaria angustifolia; fragmento florestal. AbstractSoil seed bank analysis in a forest fragment with Araucaria angustifolia, State of Parana. A research on soil seed bank had been developed in an Araucaria angustifolia (Bert.) O. Ktze. forest fragment in the State of Paraná. It had surveyed vertical distribution of seeds within the soil and shadow influence on seedling emergence, besides the improvement of their identification and quantity measuring. Vertical distribution of seeds in four soil layers had been analyzed by identification and quantification of germinated seedlings in greenhouse, with full light or 50% shaded conditions. Data related to seedlings of trees, weeds, grasses and lianas were calculated separately in weekly intervals during a 210-day period. Results suggested that the soil seed bank in this forest was poor in relation to tree species, in diversity as far as density. On the other hand, seeds of grasses and weeds decreased along vertical soil profile, and forest tree species tended to abundance in the 5-10 cm layer. Germination was higher with full light than in 50% shaded conditions. Probably, regeneration strategy for most species in this focused area doesn’t seem to be soil seed bank.Keywords: Soil seed bank; Araucaria angustifolia; forest fragment.


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