Seed Bank Formation Research Articles

Seed germination requirements of the rare Helosciadium repens (aka Apium repens) determine persistence of seeds in the soil seed bank.

The rare and threatened Heliosciadium repens grows in moist grasslands and has a distinct life cycle. Plants reproduce both clonally, although ramets tend to be short-lived, and sexually, with seeds that can form a persistent soil seed bank. The germination requirements of H. repens were investigated, yielding important information for its habitat management and conservation. We examined the soil seed bank in three populations and carried out germination experiments and embryo growth measurements with fresh seeds in laboratory, greenhouse and outdoor conditions. We also investigated the effects of storage and burial of seeds. H. repens formed a long-term persistent (>6 years) soil seed bank with very pronounced primary dormancy, but no secondary dormancy or dormancy cycles. Seeds can germinate throughout the growing season when temperatures are sufficiently high. Embryo growth and seed germination are triggered by light and, to a lesser extent, daily temperature fluctuations. Seeds of H. repens seem to have developed a unique germination syndrome with several strategies to remain dormant in the soil until optimal conditions are present for seedling establishment and survival. Both sexual reproduction and seed bank formation are crucial for the long-term survival of the populations.

Large and non-spherical seeds are less likely to form a persistent soil seed bank.

There is some evidence that seed traits can affect the long-term persistence of seeds in the soil. However, findings on this topic have differed between systems. Here, we brought together a worldwide database of seed persistence data for 1474 species to test the generality of seed mass-shape-persistence relationships. We found a significant trend for low seed persistence to be associated with larger and less spherical seeds. However, the relationship varied across different clades, growth forms and species ecological preferences. Specifically, relationships of seed mass-shape-persistence were more pronounced in Poales than in other order clades. Herbaceous species that tend to be found in sites with low soil sand content and precipitation have stronger relationships between seed shape and persistence than in sites with higher soil sand content and precipitation. For the woody plants, the relationship between persistence and seed morphology was stronger in sites with high soil sand content and low precipitation than in sites with low soil sand content and higher precipitation. Improving the ability to predict the soil seed bank formation process, including burial and persistence, could benefit the utilization of seed morphology-persistence relationships in management strategies for vegetation restoration and controlling species invasion across diverse vegetation types and environments.

Adaptive advantage of Sesbania virgata (Cav.) Pers. in the phytochemical production: the influence on fungi occurring in seeds

Sesbania virgata is a native Brazilian plant species. It exhibits rapid growth, a high soil cover potential, and efficient soil seed bank formation and is used in environmental restoration projects. The soil seed bank is susceptible to fungal infection and other biotic factors. However, only a few studies have reported on the fungi on the surface of S. virgata seeds. Moreover, little is known about how substances present in the seed integument affect fungal communities and their role in adapting to and thriving in new environments. Herein, S. virgata seeds were collected from populations that produce or do not produce the flavonoid catechin in the seed coat. These seeds were subjected to laboratory tests to identify and quantify the fungal populations in the integument. We selected and subjected three genera to irrigation and inoculation tests with S. virgata extracts and seeds from both populations. We observed that the aqueous seed coat extracts inhibited Alternaria sp. micellar and augmented Phoma sp. growth. Phoma sp. also caused post-germinated seed lethality. Our data indicate that the seed coat of S. virgata contains antifungal substances that endow this species with an adaptive advantage.

Germination and Secondary Dormancy Of Hydrocharis Dubia (Blume) Seed

The germination of freshly harvested, dry-stored and wet-stored Hydrocharis dubia seeds were treated with exogenous GA3, cold stratification, puncture, different temperatures and combined treatments under controlled laboratory conditions. The results showed that: The optimal temperature for H. dubia seed germination is 23℃ and fresh seed has conditional dormancy, which can be released by puncture. Seed germination percentage decreased significantly after dry seed storage and the main reason for the reduction of "seed germination ability" by dry storage was that dry storage. caused secondary dormancy but a reduction of seed vigor. The secondary dormancy is non- deep physiological dormancy, which can be released by cold stratification, seed puncture and combination treatments. The findings provided further insight into how germination strategy contributes to the seed bank formation and species reproduction. Bangladesh J. Bot. 52(2): 429-435, 2023 (June)

海草床种子扩散过程及种子库形成机制研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 海草床种子扩散过程及种子库形成机制研究进展 DOI: 10.5846/stxb202108262396 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划(2019YFE0121500);国家自然科学基金委-山东联合基金(U2006215);唐仲英基金会 A review on seed dispersal process and mechanism of seed bank formation of seagrass meadows Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:海草是唯一一类可以完全生活在海水中的高等被子植物,具有重要的生态服务功能和巨大的经济价值。但受气候变化和人类活动的双重影响,海草床退化趋势日益严峻。海草床生态系统受到外界胁迫后的稳定性和恢复能力很大程度上依赖于有性繁殖即种子繁殖,当胁迫造成海草死亡等不可逆转的伤害时,通过沉积物种子库能够进行种群维持和自我更新,因此研究海草种子扩散过程及种子库形成机制对海草生态系统稳定性的维持具有重要意义。综述了海草生活史类型、种子繁殖特征、种子扩散过程及影响因素、种子库形成机制等。在此基础上总结了目前研究存在的几方面不足和未来展望:1)不同环境胁迫条件对海草有性繁殖努力的影响研究;2)海草种子二次扩散的影响因素和扩散机制研究;3)沉积物沉降和再悬浮对种子扩散和截留的影响研究;4)环境因素变化下种子库的潜在分布和海草适宜生境预测与模拟。本研究以期为海草床生态系统的保护恢复研究提供理论参考。 Abstract:Seagrasses are the only higher angiosperms fully living in marine environments, which have important ecosystem service functions and enormous economic value. However, in recent years, the structure and function of seagrass ecosystems have been threatened by multiple global stressors caused by human activities and climate change, resulting in the continuous degradation of seagrasses. The stability and resilience of the seagrass ecosystem under external stress depend highly on its sexual reproduction, i.e., seed reproduction. When stressors cause irreversible damage to seagrasses, population maintenance and self-renewal could occur through sediment seed banks. Therefore, it is crucial to study the dispersal processes of seeds and the mechanism of seed bank formation, which play a key role in maintaining seagrass ecosystem stability. This paper reviews the life-history types, seed reproductive characteristics, seed dispersal processes and their influencing factors and seed bank formation of seagrass. On the basis of these understandings, we further proposed that future studies should focus on: 1) sexual reproductive efforts of seagrass under different environmental stress conditions; 2) the influencing factors and mechanism of secondary dispersal of seagrass seeds; 3) the influence of sediment deposition and resuspension on seed dispersal and retention processes; 4) prediction and simulation of the potential distribution of seagrasses and suitable habitat of seed bank under changing environments. This study is expected to provide theoretical references for the protection and restoration of seagrass meadow ecosystems. 参考文献 相似文献 引证文献

Dormancy and viability ofFerocactus peninsulae(Cactaceae) seeds

AbstractKnowledge on seed dormancy is crucial for the understanding of plant population dynamics, as it controls seed germination and seed bank formation. Dormant seeds have high potential to establish in soil seed banks, but such information within Cactaceae is scarce, although it is essential for conservation programs. The aim of this study was to determine if seeds ofFerocactus peninsulaeshowed any kind of dormancy and to test their germination capacity after storage. This was assessed with 15 seed sowing experiments done over 4 years with seeds stored under room conditions (20 ± 2°C). We demonstrated the existence of physiological dormancy inF. peninsulaeseeds that is broken with an after‐ripening period. Germination was low during the first 3 months of storage (d = 0.206) but increased after 10 months of storage (d = 0.654), and seeds maintained their viability at 48 months (d = 0.707). Also, their speed of germination increased with storage time.Ferocactus peninsulaeseeds are positively photoblastic, and the requirement for light for germination persisted over all experiments. The results provide crucial information for propagation and conservation research and may allow us to infer thatF. peninsulaeseeds are able to form a persistent soil seed bank, as they maintained their viability after dormancy is released.

Potential of arboreal individuals as facilitators of seed bank formation in a Cerrado and Caatinga ecotone.

RESUMO Este estudo verificou as diferenças na riqueza, densidade e composição de espécies do banco de sementes sob a copa es espécies arbóreas e a área de campo adjacentes e a relação entre altura total do caule e área da copa com a densidade e riqueza do banco de sementes. Foram coletados o banco de sementes sob a copa de 10 indivíduos de cada espécies (Curatella americana L., Luetzelburgia auriculata (Allemão) Duckee, Copernicia prunifera (Mill.) H.E.Moore)), e em 10 pontos em área de campo adjacente. A densidade e riqueza do banco de sementes foram maiores sob as copas das espécies. A altura do caule apresentou relação positiva com riqueza e densidade do banco de sementes e, área da copa relação negativa. As espécies arbóreas estudadas potencializam a formação de banco de sementes, aumentando a riqueza e densidade. Também influenciam na distribuição das espécies e na diversidade local.

Invasion of the North American sand dropseed (Sporobolus cryptandrus) – A new pest in Eurasian sand areas?

For the effective control of an invasive species, gathering as much information as possible on its ecology, establishment and persistence in the affected communities is of utmost importance. We aimed to review the current distribution and characteristics of Sporobolus cryptandrus (sand dropseed), an invasive C4 grass species of North American origin recently discovered in Hungary. We aimed to provide information on (i) its current distribution paying special attention to its invasion in Eurasia; (ii) the characteristics of the invaded habitats in Central Europe; (iii) seed bank formation and germination characteristics, crucial factors in early establishment; and (iv) the effects of its increasing cover on vegetation composition. Finally, we aimed to (v) point out further research directions that could enable us to understand the invasion success of this potential invasive species. Field surveys uncovered large stands of the species in Central and Eastern Hungary with most of the locations in the former, especially in the Kiskunság region. The species invaded disturbed stands of dry and open sand grasslands, closed dune slack grasslands and it also penetrates natural open sand grasslands from neighboring disturbed habitats. Increasing cover of Sporobolus cryptandrus was associated with a decline in species richness and abundance of subordinate species both in the vegetation and seed banks, but a low density of Sporobolus cryptandrus can even have a weak positive effect on these characteristics. Viable seeds of Sporobolus were detected from all soil layers (2.5 cm layers measured from the surface to 10 cm in depth), which indicates that the species is able to form a persistent seed bank (1114 to 3077 seeds/m 2 with increasing scores towards higher abundance of the species in vegetation). Germination of Sporobolus cryptandrus was negatively affected by both litter cover and 1 cm deep soil burial. To sum up, Sporobolus cryptandrus can be considered as a transformer invasive species, whose spread forms a high risk for dry sand and steppe grasslands in Eurasia. We can conclude that for the effective suppression of the species it is necessary: (i) to clarify the origin of the detected populations; (ii) to assess its competitive ability including its potential allelopathic effects; (iii) to assess its seed bank formation potential in habitats with different abiotic conditions; and (iv) to assess the possibility of its suppression by natural enemies and management techniques such as mowing or livestock grazing. • We studied the distribution and characteristics of the invasive sand dropseed. • The species invades degraded grasslands, undisturbed sand grasslands and steppes. • With increasing dropseed cover declining plant species diversity was found. • Persistent seed banks and an effective germination of the species was detected. • Spread of sand dropseed forms a high risk for dry sand grasslands in Eurasia.

Key decision-making criteria for dormancy-breaking and ability to form seed banks of Cerrado native tree species

ABSTRACT Ecological restoration by direct seeding in the Cerrado biome still lacks information about native species germination, the need for dormancy overcoming and seed bank formation. This study aims to verify the effects of dormancy overcoming on germination of four tree species and the ability of 12 tree species to form seed banks for restoration use. Our results showed wide variation of species’ germination rates. Overcoming dormancy enhanced germination for Dimorphandra mollis, Hymenaea stigonocarpa, and Peltophorum dubium and decreased it for Copaifera langsdorffii, but was only cost-effective for H. stigonocarpa. Regarding the ability to form seed banks, only H. stigonocarpa and Cecropia pachystachya germinated and live seedlings of Terminalia corrugata were found after being buried for six months, thus forming a transient seed bank. Despite the fact that overcoming dormancy may optimize germination after direct seeding, maintaining dormancy mechanisms of species that can form seed banks could be essential for species establishment over time in restoration areas. Hence, our key decision criteria based on seed costs and seed and labor availability would be useful for the seeding actions of restoration practitioners.

Different response of transient and persistent seed bank of alpine wetland to grazing disturbance on the Tibetan Plateau

With increased grazing disturbance of wetlands, soil moisture decreases, which could have an effect on the seed bank. The seed bank is a crucial resource for vegetation restoration; however, the effects of grazing disturbance on density and richness of seed banks and consequences on restoration of degraded wetlands are unclear. We selected six alpine wetlands along a degradation gradient on the Tibetan Plateau for study. The structural equation model was used to explore the direct and indirect effects of soil moisture on transient and persistent seed banks through soil physicochemical factors and vegetation. Non-metric multidimensional scaling was used to explore the role of seed banks in alpine wetland vegetation regeneration. A decrease in soil moisture directly increased richness and density of the transient seed bank. However, decreased soil moisture indirectly decreased density of transient and increased richness and density of the persistent seed bank though soil pH and richness and abundance of vegetation. The similarity between the seed bank and vegetation increased with wetland degradation. Slope of the Bray-Curtis dissimilarity between transient seed bank and vegetation was higher than that for the persistent seed bank and vegetation. Transient seed banks remained almost constant under grazing disturbance, which favours persistent seed bank formation. Transient and persistent seed banks were determined by aboveground vegetation and soil environment, respectively. Seed banks provide strong resistance and resilience to degradation of wetland ecosystems, while persistent seed banks play a more important role than transient seed banks in restoration of degraded alpine wetlands.

Seed bank formation and removal of Pinus hartwegii (Pinaceae) seeds along an altitudinal gradient in the Cofre de Perote National Park, Veracruz, Mexico

Background: Seed banks, an important element in the natural regeneration of plant communities, are regulated mostly by granivores along an altitudinal gradient.
 Question/Hypothesis: Pinus hartwegii forms transient and probably persistent seed banks along an altitudinal gradient. Seed removal will vary according to the removing agents, the altitude and the season.
 Species under study/Data description/Mathematical model: The formation of seed banks and the removal of Pinus hartwegii (Pinaceae) seeds along an altitudinal gradient were evaluated in different seasons using a linear model with two factorial variance analyses. 
 Site and years of study: The study was conducted at the Cofre de Perote National Park, Veracruz, Mexico, over an altitudinal gradient (at 3,400, 3,600, 3,800 and 4,000 m a.s.l.) in July-September 2015 (rainy season), and January-March 2016 (dry season). 
 Methods: In order to understand seed bank formation and identify the removal agents along an altitudinal gradient, two experiments were conducted with seeds from 10 trees at each altitudinal tier.
 Results: The results of the first experiment, after one year, demonstrated the formation of transient and probably persistent seed banks along an altitudinal gradient ( P < 0.0001). The results of the second experiment showed significant variations in seed removal according to the removal agents and the seasons ( P < 0.0001).
 Conclusions: Pinus hartwegii forms transient and probably persistent seed banks along an altitudinal gradient. Seed removal varies according to altitude and season.

The role of the soil seed store in the survival of an invasive population of Poa annua at Point Thomas Oasis, King George Island, maritime Antarctica

Poa annua, an invasive species in the Antarctic, had established a relatively large population at Point Thomas Oasis (Maritime Antarctic) recorded from 1985/1986 austral summer. We present a detailed account of the expansion of P. annua across its 30 years of establishment (1985/1986, 1986/1987, 1987/1988, 1989/1990 and 1991/1992 – historic data, 2014/2015 and 2015/2016 – our own observations) and how this relates to the historical human activity at this site. We also evaluate the first stages of the control effort, i.e. tussock removal by hand. For a subset of the removed tussocks we also removed soil in order to assess the importance of the soil seed bank in the course of this invasion. The population showed a spatio-temporal dynamic increase in area from 1985/1986 to 1987/1988 growing season followed by a decrease in area noted in 1989/1990 and subsequent increase in area and diversity of occupied habitats. Analysis of distribution dynamics did not show a significant difference in the number of tussocks recorded in the 2014/2015 austral summer between cartogram squares occupied in 1991/1992 or earlier, and those occupied just in 2014/2015. There was, however, a high correlation in the number of tussocks per square between the 2014/2015 and 2015/2016 census. Field observations conducted in 2015/2016 within the whole Point Thomas Oasis indicated that on 6 out of 51 sites cleared during the 2014/2015 austral summer, P. annua had re-established, mostly on sites where no soil was collected. Of the soil samples removed from beneath tussocks, seed germinated in 19% of the samples (160 seedlings in total). These results indicate that the strategy of soil seed bank formation has been very effective in extreme Antarctic conditions, providing a ‘temporal rescue effect’ which has enabled the survival of the population, and hinders the effective eradication of this invasive species.

CHUVA DE SEMENTES E ESTABELECIMENTO DE PLÂNTULAS EM FLORESTA TROPICAL NA REGIÃO NORDESTE DO BRASIL

Mecanismos de regeneração natural são fundamentais para o restabelecimento das funções ecológicas de fragmentos florestais e de áreas degradadas. O presente trabalho teve como objetivo avaliar a chuva de sementes e o estabelecimento de plântulas de espécies arbóreas em Floresta Atlântica, localizada na região Nordeste do Brasil. Para amostragem da chuva de sementes foram alocados 60 coletores (área de 0,196 m²), ficando equidistantes, aproximadamente, de 50 m. As coletas foram realizadas com intervalo de 30 dias por um período de 12 meses. Para avaliar o estabelecimento de plântulas foram alocadas subparcelas ao lado dos coletores, totalizando 60 subparcelas de 0,25 m² cada. Os indivíduos arbóreos identificados pelos diásporos coletados na chuva de sementes e pelas plântulas estabelecidas no fragmento foram contados e classificados quanto à síndrome de dispersão e grupo sucessional. A chuva de sementes foi representada por 60 morfoespécies e 20 famílias botânicas. O grupo ecológico e a síndrome de dispersão predominante foram de espécies secundárias iniciais e zoocórica, respectivamente. Em relação às plântulas estabelecidas foram contadas 122 plântulas, sendo Tapirira guianensis L. com maior número de plântulas. A chuva de sementes apresenta potencial para manutenção da dinâmica florestal por apresentar alta riqueza de espécies que compõe a atual vegetação, sendo composta, predominantemente, por espécies que produzem frutos abundantes com dispersão zoocórica que servem de alimento para fauna. Enquanto poucas sementes germinam para formar o banco de plântulas, a maioria está contribuindo para formação do banco de sementes.

Climatic control of seed longevity of Silene during the post-zygotic phase: do seeds from warm, dry climates possess higher maturity and desiccation tolerance than seeds from cold, wet climates?

Seed longevity derived from artificial ageing experiments has been shown to be related to the macroclimate at the sampling site and with individual seed traits. Nevertheless, the ecological interpretation of artificial seed longevity remains to be clarified. In this article, the ecological significance of seed longevity expressed by the p50 index was explored using 16 closely related populations of the genus Silene L. Seeds were subjected to an artificial ageing treatment at 45 °C, 60% relative humidity and regularly tested for germination. The decline of viability to 50% (p50 index) was calculated using probit analysis. Its relationship with known ecological predictors of seed longevity was assessed by multiple regression analysis. Values of p50 ranged from 3.7 to 68.3 days. Seed lots which normally experience drought during the post-zygotic phase in a dry, warm environment, were long-lived. Consistently, precipitation during the driest months of the reproductive period was the strongest predictor of p50 variability (partial regression, R 2 = 0.424). We could not find any relationship between ex situ seed longevity and soil seed bank formation or seed size. Our results indicate that ex situ seed longevity has an ecological significance related to long-term climatic differences at population site. Increased longevity presumably reflects resistance to desiccation stress attained by seeds through local adaptation to warm, dry climates. We cannot exclude that seed tolerance to ageing could also represent phenotypic plasticity mediated by a drier maturation environment. The vulnerability of seeds from wet, cool climates and the adaptive response of seed longevity to different environments may have implications for ex situ conservation in the face of climate warming.

The seed ecology ofAegilops triuncialis: linking trait variation to growing conditions

AbstractAdaptive plastic responses in invasive species allow for establishment and persistence despite the lack of genetic matching to new environments. The capacity of annual species to invade habitats to which they are not adapted is likely to be predicated on post-invasion seed trait variation correlated with conditions in the new habitat. To test this, I compared variation in seed traits and germination patterns ofAegilops triuncialis, an invasive annual grass, from 69 sample populations from 24 sites in California (USA) across 13 years. Seed mass, germination fractions, seed viability, and strength of induced dormancy between dimorphic seed pairs were used to investigate plastic variation within and among populations, across two general soil types, and among two widespread maternal genotypes. I found that seed mass variation was constrained although both seed types showed a 3-fold range among populations, 20–25% variation within populations between years, and was positively correlated with longer growing seasons. However, induced seed dormancy in the small seed type was correlated with large seed mass and to late-season precipitation, suggesting that longer growing seasons influence the strength of maternal and sibling chemical signals that induce dormancy in the small seeds. Thus variation in small seed germination fractions varies with the growing conditions experienced by the maternal plant. The greater longevity of the small seed type suggests that plasticity in germination in this species may contribute to seed bank formation, which is atypical of invasive annual grasses in California, and this may contribute to the persistence and spread ofA. triuncialisin invaded ranges.

Epigeal Fauna and Soil Chemical Attributes in Grazing and Regeneration Areas

ABSTRACT The objective of this study was to evaluate the influence of natural pasture and spontaneous regeneration on soil chemical properties and epigeal fauna community using a secondary Atlantic Forest as reference. The study areas were located in Passa Vinte, Minas Gerais, Brazil. In each study area, pitfall traps were used to sample epigeal fauna in the dry and rainy seasons. Earth samples were collected at a depth of 0-5 cm in the dry and rainy seasons for analysis of chemical attributes. The pasture and regeneration areas showed an overall activity of epigeal fauna and functional groups similar to the forest area. However, the diversity evaluated by the Shannon and Pielou evenness indices and the total richness were lower than the observed in the forest. The best fertility attributes were observed in the forest and pasture areas. Keywords: land use, diversity, forest fragments. 1. INTRODUCTION The Atlantic Forest is the most fragmented Brazilian biome and the second largest tropical rainforest in the Americas. It originally spread throughout an uninterrupted strip across the Brazilian coast (Fundacao SOS Mata Atlântica, 2001). Although the Atlantic Forest is one of the hotspots on the planet in terms of biological diversity, it is also one of the most threatened biomes (Brasil, 2015 ). Because of anthropogenic interference (deforestation), most forest remnants in this biome are small, highly disturbed, isolated, little known, little protected ( Menezes et al., 2009 ), and often surrounded by agricultural crops and pastures and regenerating forests.Deforestation for agricultural purposes followed by pasture and/or spontaneous regeneration may generate a landscape with different levels of ecological degradation/restoration. The spontaneous regeneration is an essential process for restoration of degraded areas, since it promotes the addition of new individuals. The mechanisms involved in this process (seed falls, soil seed bank formation and seedling and young plant banks) increase the density and richness of species in the community and contribute to ecological succession and its biological diversity. Spontaneous regeneration can make ecological interrelations stronger and contribute to the restoration of the system, and also to its increase in complexity and consequent self-sustainability (Quintela, 2005), which is essential in the case of the Atlantic Forest.Chemical, physical and biological soil attributes are among the main indicators for evaluating environmental restoration and degradation processes ( Silva et al., 2012a ;

Formación del banco de semillas durante la revegetación temprana de áreas afectadas por la minería en un bosque pluvial tropical del Chocó, Colombia

Mining is one of the main economic activities in many tropical regions and is the cause of devastation of large areas of natural tropical forests. The knowledge of the regenerative potential of mining disturbed areas provides valuable information for their ecological restoration. The aim of this study was to evaluate the effect of age of abandonment of mines and their distance from the adjacent forest, on the formation of soil seed bank in abandoned mines in the San Juan, Chocó, Colombia. To do this, we determined the abundance and species composition of the soil seed bank, and the dynamics of seed rain in mines of different cessation period of mining activity (6 and 15 years), and at different distances from the adjacent forest matrix (50 and 100 m). Seed rain was composed by five species of plants with anemocorous dispersion, and was more abundant in the mine of 6 years than in the mine of 15 years. There were no significant differences in the number of seeds collected at 50 m and 100 m from the adjacent forest. The soil seed bank was represented by eight species: two with anemocorous dispersion (common among the seed rain species) and the rest with zoochorous dispersion. The abundance of seeds in the soil did not vary with the age of the mine, but was higher at close distances to the forest edge than far away. During the early revegetation, the formation of the soil seed bank in the mines seems to be related to their proximity to other disturbed areas, rather than their proximity to the adjacent forest or the cessation activity period of mines. Therefore, the establishment of artificial perches or the maintenance of isolated trees in the abandoned mines could favour the arrival of bird-dispersed seeds at mines. However, since the soil seed bank can be significantly affected by the high rainfall in the study area, more studies are needed to evaluate management actions to encourage soil seed bank formation in mines of high-rainfall environments in the Chocó region.

Longevidad y germinación de semillas de Syagrus romanzoffiana (Arecaceae) y sus implicaciones ecológicas

<strong><em>Syagrus romanzoffiana</em> is a palm tree native and widely distributed of South America.</strong> <strong>The present study investigated the longevity and germination of the buried seeds of this species in an experimental seed bank.</strong> <strong>Laboratory germination and</strong> <strong>viability tests were performed for comparison with field results. Pyrenes (seeds enclosed by the endocarp) were buried in a forest fragment edge in July (dry season) in July 2012 and exhumed monthly during one year, for the assessment of water content</strong> <strong>and percentage of germinated and viable seeds.</strong> <strong>Germination tests</strong> <strong>were conducted in a Mangelsdorf-type germinator at 30°C under constant light and the viability was </strong><strong>assessed by the tetrazolium test. An additional sample of</strong> <strong>pyrenes was buried to evaluate the percentage of seedling emergence and survival. Climatic</strong> <strong>and soil moisture</strong> <strong>data</strong> <strong>were recorded.</strong> <strong>In the laboratory, the pyrenes were stored for one year in a temperature-controlled room at 20ºC and 75% (±10%) relative air humidity to assess changes in the percentage of germination and viability over time.</strong> <strong>In the field, a reduction in seed viability</strong> <strong>was observed over the study period, with a total loss of viability of non-germinated seeds at seven months after burial.</strong> <strong>The maximum germination (close to 26%) was observed in the samples that were exhumed between five and seven months after burial. In the field, seedling emergence did not exceed 10% and seedling mortality was not observed. The percentages of germination and of viable seeds decreased both in burial and stored seeds. The stored seeds maintained viability at up to six months, with marked reduction thereafter. After the germination tests (four months) in the laboratory, all of the remaining seeds were nonviable. The ecological, physiological</strong> <strong>and reproductive characteristics of the species are discussed, and we concluded that</strong> <strong><em>S. romanzoffiana</em></strong> <strong>seeds have short longevity after imbibition, and low potential for soil seed bank formation.</strong>

Interactive effects between physical forces and ecosystem engineers on seed burial: a case study using Spartina anglica

Seed burial (i.e. vertical seed dispersal) has become increasingly valued for its relevance for seed fate and plant recruitment. While ecosystem engineers have been generally considered as the most important drivers of seed burial, the role of physical forces, such as wind or water flow, has been largely overlooked. Using tidal habitats as a model system, and a combination of flume and mesocosm experiments, we investigated the effects of 1) currents, 2) benthic animals with different engineering activities and 3) their interplay on seed burial of a common salt marsh pioneer plant, Spartina anglica. Our results reveal that in such systems, water flow can be of equal or higher importance than ecosystem engineers for seed burial. For passive seed‐burying engineers (PSE), coupling their actions with currents produced synergistic seed burial effects, whereas the interactive effects were only additive for active seed‐burying engineers (ASE). This paper extends current understanding of seed burial and seed bank formation by revealing the need to incorporate physical forces into seed burial mechanisms. We provide the first empirical evidence that physical forces influence seed burial by synergistically interacting with ecosystem engineers, thus highlighting the role of biophysical interactions as important drivers for vertical seed movement.

The action of post-dispersal beetles (Coleoptera: Scarabaeidae) and ants (Hymenoptera: Formicidae) on scats of Didelphis spp. (Mammalia: Didelphidae)

A two year study of dung beetles and ants acting on scats of two species of opossum (Didelphis spp.) was carried out. Scats were left in the field in order to detect post-dispersal agents. A portion of each scat (30 %) was examined for seeds in the laboratory. Beetles were recovered from burrows (51% of 84 faecal samples left in the field) where they either buried scats of opossums or were attracted, together with ants, to pitfalls (N = 10) baited with opossum scats. Dung beetles were the main post-dispersal agents of seeds found in scats of opossums, rolling the scats away or burying then on the site of deposition. They buried faeces at 4 to 15 cm in depth (N = 22 tunnels). The main dung beetles identified (medium to large size) were Eurysternus (28.7 % in pitfalls) and Dichotomius (13.7 %), Coprophanaeus (seen only directly on faeces), besides small-bodied beetles (< 10 mm; 57.6 %). The ant Acromirmex sp. transported some seeds from scats. This species was present in 25.5 % of all Formicidae samples (pitfall). These post-dispersal agents contribute to avert scat seed predators such as rodents, and to accelerate seed bank formation.