Can spatial variation and inter-annual variation in precipitation explain the seed density and species richness of the germinable soil seed bank in a tropical dry forest in north-eastern Brazil?

Abstract:Seasonal fluctuations in bird abundance are expected in semi-arid environments, but estimates may be biased if detectability is not considered. In a tropical dry forest in north-eastern Brazil, we evaluated whether bird abundance is highly seasonal, and associated with time-specific variability in detectability. We mark-recaptured birds with mist nets over three field visits (3487 records from 75 species), and used closed-capture models to estimate detectability and abundance in birds divided into three groups (all, residents, insectivores). In the two dry periods, the best models resulted in capture estimates at least three times larger than recapture, and both estimates were twice that of when rains occurred on the day preceding sampling. Abundance varied between dry and wet periods from 4.0 (from 115 ± 34 to 479 ± 144) to 13 times (183 ± 8 to 2463 ± 351). Estimates were 1.5–3.2 times greater in the dry period when behavioural responses of birds were excluded from capture-recapture models. Meanwhile, in the wet period the relative abundance was between 33–76% smaller than best-fit models estimated. This study found variation in avian abundance greater than that observed in other Neotropical dry forests, and indicates that biases may be common when not including detectability.

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Impact of forest fire on soil seed bank composition in Himalayan Chir pine forest

Journal of Plant Ecology ◽

10.1093/jpe/rtz060 ◽

2019 ◽

Vol 13 (2) ◽

pp. 177-184

Author(s):

Bobbymoore Konsam ◽

Shyam S Phartyal ◽

Nagendra P Todaria

Keyword(s):

Species Richness ◽

Forest Fire ◽

Seed Bank ◽

Soil Depth ◽

Soil Seed Bank ◽

Pine Forest ◽

Seed Density ◽

Postfire Regeneration ◽

Standing Vegetation ◽

Chir Pine

Abstract Aims To explain how plant community copes with a recurring anthropogenic forest fire in Himalayan Chir pine forest, it is important to understand their postfire regeneration strategies. The primary aim of the study was to know: (i) how fire impact soil seed bank composition and (ii) how much soil seed bank composition differs with standing vegetation after the forest fire. Methods Soil samples were collected from burned and adjoining unburned sites in blocks using three layers down to 9 cm depth immediately after a forest fire and incubated in the net-house for seedling emergence. Same sites were revisited during late monsoon/early autumn season to know the species composition of standing vegetation recovered after a forest fire. Important Findings Soil contained viable seeds of >70 species. The average seed bank density was 8417 and 14 217 seeds/m2 in the burned and unburned site, respectively. In both sites, it decreased with increasing soil depth. Overall fire had no significant impact on seed density; however, taking individual layers into consideration, fire had a significant impact on seed density only in the uppermost soil layer. The species richness of soil seed bank and standing vegetation was 73 and 100, respectively (with 35 shared species), resulting in a similarity of about 40%. In contrast, >80% species in soil seed bank was found similar between burned and unburned sites. Further, there were no significant differences in species richness of standing vegetation in burned (87 spp.) and unburned (78 spp.) sites. Our results showed that fire had an insignificant impact on soil seed bank composition and restoration potential of a plant species from seeds. The understory herb and shrub plant community’s ability to form a fire-resistant viable soil seed bank and capable to recover in the postfire rainy season, explains how they reduce the risk of recurring fire damage in maintaining their population.

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Natural vegetation regeneration from soil seed banks in the cultivated edges of Sudd wetlands in Juba, Southern Sudan

East African Journal of Science, Technology and Innovation ◽

10.37425/eajsti.v2i2.214 ◽

2021 ◽

Vol 2 (2) ◽

Author(s):

Josephine Esaete ◽

Augustine Bongo ◽

Thomas Lado ◽

Tomor Bojoi ◽

Henry Busulwa

Keyword(s):

Species Richness ◽

Species Composition ◽

Seed Bank ◽

Natural Regeneration ◽

Soil Seed Bank ◽

Seed Banks ◽

Interquartile Range ◽

Seed Density ◽

Soil Seed Banks ◽

Species Richness And Diversity

Soil seed banks are important for regeneration of degraded wetlands ecosystems. The Sudd wetlands of Juba city have long been encroached for crop cultivation. Seedling germination was monitored in a greenhouse to establish possible natural regeneration in Mindiari, Rejaf and Roton wetlands in the Sudd. Sixty-four species germinated from the soil seed bank of which 12.5% were dominated by Cyperus difformis and Typha capensis. The findings showed that median wetland species richness in Mindiari was 1.5 (interquartile range = 0.75?3.5), Rejaf 2.5 (interquartile range = 1.0 ? 4.0), Roton 3 (interquartile range = 1.0 ? 5.0) while median Shannon-Wiener diversity was 1.5 (1.14 ?1.73), 1.43 (1.01?1.66), 1.15 (0.98?1.67) for Mindiari, Rejaf and Roton respectively. Both the median seed species richness and diversity were not significantly different among the study wetlands. The median of seed density (56.1) was significantly higher in Roton than in Mindiari (36.7) and Rejaf (29.4) wetlands. The NMDS results showed that species composition of Mindiari and Rejaf was different from Roton. It is concluded that growing crops in wetlands did not influence species richness and diversity but it reduced seed density and altered species composition. Although wetland species were not significantly different in the three-wetland categories, dominance of canopy species belonging to Typhaceae and Cyperaceae indicates that these species are resilient to cultivation and could facilitate natural regeneration of cultivated wetlands edges of the Sudd region in Juba. Further research should examine effect of cultivation duration and flooding regimes on soil seed bank species richness, diversity, and density and composition.

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¿Qué ocurre con el banco de semillas del suelo 17 años después del corte de la vegetación?

Revista de Biología Tropical ◽

10.15517/rbt.v63i2.14683 ◽

2015 ◽

Vol 63 (2) ◽

pp. 321 ◽

Cited By ~ 5

Author(s):

Leonardo Brasil Mendes ◽

Kleber Andrade da Silva ◽

Danielle Melo dos Santos ◽

Josiene Maria Falcão Fraga dos Santos ◽

Ulysses Paulino De Albuquerque ◽

...

Keyword(s):

Species Richness ◽

Seasonal Variation ◽

Leaf Litter ◽

Seed Bank ◽

Soil Depth ◽

Dry Forest ◽

Annual Rainfall ◽

Seed Density ◽

Mature Forest ◽

Young Forest

Seed banks play an important role in the resilience of potential anthropogenic areas and are influenced by seasonal variation. The spatial and temporal heterogeneity of the forests influences the richness and density of the soil seed bank, but there is a hypothesis that such influence can be changed in anthropogenic areas, where we expect to find lower richness and seed density in relation to the seed bank of mature forests. The richness and seasonal density of seeds in the soil depth of a young caatinga forest, 17 years after an agricultural activity was abandoned, were evaluated and compared with those of a mature forest. The study was conducted at the Instituto Agronômico de Pernambuco - IPA (Estação Experimental José Nilson de Melo), located in Caruaru, Pernambuco, Brazil, in an area of tropical dry forest, known locally as “caatinga”. The local climate is seasonal, the dry season occurring from September to February and the rainy season concentrated in the remaining months. The average annual rainfall over time (time series of 30 years) is 692mm. In each climatic season (rainy and dry), the seed bank was sampled in 210 20x20cm plots (105 in the leaf litter and 105 at 5cm soil depth). The richness and seed density of the soil samples were evaluated by the method of seedling emergence. The seed bank had 47 species, with a predominance of herbaceous plants. Seasonal variation in richness and seed density in the soil (leaf litter + soil) was not significant, but 42 species of the mature forest were absent from the seed bank of the young forest, despite 17 years of natural regeneration and its proximity to the mature forest. On its own, the soil has greater richness and density of seeds than the leaf litter. The depth of seed deposition in the soil bank of the young forest significantly explained 36% of the species richness and 16% of the seed density, with a significant interaction effect with the climatic season only on species richness, explaining 4% of the variation recorded. The seed density of the young forest (1 277seeds/m<sup>2</sup>) was greater than that the mature forest indicating that the time abandoned had not yet been sufficient for complete recovery of plant diversity and there is no longer any seed limitation of pioneer species for regeneration of the young forest.

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Relationships between soil seed bank composition and standing vegetation along chronosequences in a tropical dry forest in north-eastern Brazil

Journal of Tropical Ecology ◽

10.1017/s0266467419000130 ◽

2019 ◽

Vol 35 (4) ◽

pp. 173-184 ◽

Cited By ~ 3

Author(s):

Fernanda Melo Gomes ◽

Clemir Candeia de Oliveira ◽

Roberta da Rocha Miranda ◽

Rafael Carvalho da Costa ◽

Maria Iracema Bezerra Loiola

Keyword(s):

Seed Dispersal ◽

Seed Bank ◽

Soil Seed Bank ◽

Seedling Emergence ◽

Tropical Dry Forest ◽

Seed Banks ◽

Dry Forest ◽

Dry Forests ◽

High Dispersal ◽

Standing Vegetation

AbstractTo better understand the role of seed banks in ecological succession of dry forests, we compared similarities between vegetation and seed banks and assessed the relative contributions of seed dispersal and persistence in chronosequences in the Brazilian semi-arid region. To sample the standing vegetation and the seed bank, we collected data in three sites with three successional ages in each one (5 y, 25 y and 45 y). A total of 180 soil samples (three sites × three successional ages × 10 plots × two components) were collected. The composition of the seed bank was assessed by the seedling emergence method. Of 166 species identified in the standing vegetation, only 50 (30.1%) were also present in the seed bank, resulting in low similarity (Jaccard index = 0.02–0.21) and reflecting the rarity of woody species and the dominance of annuals (71% of richness). The relative importance of seed persistence and seed dispersal to seed banks composition were balanced in most cases (difference was not rejected in four out six comparisons). Those results suggest that seed banks in tropical dry forests are largely the result of high dispersal rates and the persistence of allochthonous annual species that contribute to decoupling seed bank and vegetation composition.

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Species Richness, Spatial Variation, and Abundance of the Soil Seed Bank of a Secondary Tropical Rain Forest1

Biotropica ◽

10.1111/j.1744-7429.1998.tb00056.x ◽

1998 ◽

Vol 30 (2) ◽

pp. 214-222 ◽

Cited By ~ 51

Author(s):

Brett J. Butler ◽

Robin L. Chazdon

Keyword(s):

Species Richness ◽

Spatial Variation ◽

Seed Bank ◽

Soil Seed Bank

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Dynamics in the emergence of dormant and non-dormant herbaceous species from the soil seed bank from a Brazilian dry forest

Journal of Plant Ecology ◽

10.1093/jpe/rtaa008 ◽

2020 ◽

Vol 13 (3) ◽

pp. 256-265 ◽

Cited By ~ 1

Author(s):

José Djalma de Souza ◽

Bruno Ayron de Souza Aguiar ◽

Danielle Melo dos Santos ◽

Vanessa Kelly Rodrigues de Araujo ◽

Júlia Arruda Simões ◽

...

Keyword(s):

Seed Bank ◽

Linear Models ◽

Temporal Dynamics ◽

Soil Seed Bank ◽

Seed Banks ◽

Dry Forest ◽

Herbaceous Species ◽

Physical Dormancy ◽

Soil Seed Banks ◽

Interspecific Differences

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.

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The effects of recreation disturbance on subalpine seed banks in the Rocky Mountains of Montana

Canadian Journal of Botany ◽

10.1139/b00-031 ◽

2000 ◽

Vol 78 (5) ◽

pp. 577-582 ◽

Cited By ~ 13

Author(s):

Catherine Zabinski ◽

Todd Wojtowicz ◽

David Cole

Keyword(s):

Organic Matter ◽

Seed Bank ◽

Soil Seed Bank ◽

Seedling Emergence ◽

Seed Density ◽

Soil Cores ◽

Bare Ground ◽

Recreation Impacts ◽

Natural Revegetation ◽

Site Types

We investigated the soil seed bank in a subalpine ecosystem with patchy disturbance from camping. Soil cores were collected from three site types, heavily impacted, lightly impacted, and undisturbed, that differed in area of bare ground and depth of surface organic matter. We hypothesized that the density and composition of the seed bank would vary with depth of surface organic matter and distance from established vegetation. Seedling emergence was determined in the greenhouse. Seed density was significantly lower on disturbed sites, averaging 441 seeds/m2 on heavily impacted sites, 1495 seeds/m2 on lightly impacted sites, and 4188 seeds/m2 on undisturbed sites. Seed density declined exponentially with distance from established vegetation and increased with depth of surface organic matter. The number of species present did not vary across site types, but 10 species that occurred on lightly impacted and undisturbed sites were not present on heavily impacted sites. We concluded that disturbance that causes removal of surface organic matter can affect natural revegetation by lowering the density of propagules and affecting the species represented in the seed bank.Key words: seed bank, subalpine, patchy disturbance, recreation impacts.

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