Search

Three-dimensional (3D) vegetation structure influences animal movements and, consequently, ecosystem functions. Animals disperse the seeds of 60%-90% of trees in tropical rainforests, which are among the most structurally complex ecosystems on Earth. Here, we investigated how 3D rainforest structure influences the movements of large, frugivorous birds and resulting spatial patterns of seed dispersal. We GPS-tracked white-thighed (Bycanistes albotibialis) and black-casqued hornbills (Ceratogymna atrata) in a study area surveyed by light detection and ranging (LiDAR) in southern Cameroon. We found that both species preferred areas of greater canopy height and white-thighed hornbill preferred areas of greater vertical complexity. In addition, 33% of the hornbills preferred areas close to canopy gaps, while 16.7% and 27.8% avoided large and small gaps, respectively. White-thighed hornbills avoided swamp habitats, while black-casqued increased their preference for swamps during the hottest temperatures. We mapped spatial probabilities of seed dispersal by hornbills, showing that 3D structural attributes shape this ecological process by influencing hornbill behaviour. These results provide evidence of a possible feedback loop between rainforest vegetation structure and seed dispersal by animals. Interactions between seed dispersers and vegetation structure described here are essential for understanding ecosystem functions in tropical rainforests and critical for predicting how rainforests respond to anthropogenic impacts.

Animals disperse seeds in various ways that affect seed deposition sites and seed survival, ultimately shaping plant species distribution, community composition, and ecosystem structure. Some animal species can disperse seeds through multiple pathways (e.g., defecation, regurgitation, epizoochory), each likely producing distinct seed dispersal outcomes. We studied how seed traits (size and toughness) interact with disperser species to influence seed dispersal pathway and how this ultimately shapes the proportion of seeds deposited in various habitat types. We focused on three frugivorous species of duikers (African forest antelopes) in the Dja Faunal Reserve, a tropical rainforest in southern Cameroon. Duikers can both defecate and regurgitate seeds, the latter predominantly occurring during rumination at their bedding sites (or "nests"). We located duiker nests and dungs along 18 linear 1-km-transects to assess: (1) how seed traits affect the likelihood of dispersal via defecation versus regurgitation, (2) if defecated versus regurgitated seeds are deposited at different rates in different forest types (assessed by indigenous Baka), microhabitats, and forest structural attributes (measured by drone lidar), and (3) if these differ between three duiker species that vary in size and diel activity patterns. We found that duikers predominantly defecated small seeds (10 mm length), the latter including 25 different plant species. The three duiker species varied in their nesting habits, with nocturnal bay duikers (Cephalophus dorsalis) nesting in dense understory vegetation at proportions 3-4 times higher than Peter's and yellow-backed duikers (Cephalophus callipygus and Cephalophus silvicultor). As a result, bay duikers deposited larger regurgitated seeds at a higher rate in habitats with denser understory where lianas and palms predominate and near fallen trees. This directed regurgitation seed deposition likely plays an important and unique role in forest succession and structure. This study highlights the importance of ungulate seed dispersal by regurgitation, a vastly understudied process that could impact many ecosystems given the prevalence of ruminating ungulates worldwide.

The flavonoid pathway is characteristic of land plants and a central biosynthetic component enabling life in a terrestrial environment. Flavonoids provide tolerance to both abiotic and biotic stresses and facilitate beneficial relationships, such as signalling to symbiont microorganisms, or attracting pollinators and seed dispersal agents. The biosynthetic pathway shows great diversity across species, resulting principally from repeated biosynthetic gene duplication and neofunctionalization events during evolution. Such events may reflect a selection for new flavonoid structures with novel functions that enable occupancy of varied ecological niches. However, the biochemical and genetic diversity of the pathway also likely resulted from evolution along parallel trends across land plant lineages, producing variant compounds with similar biological functions. Analyses of the wide range of whole-plant genome sequences now available, particularly for archegoniate plants, have enabled proposals on which genes were ancestral to land plants and which arose within the land plant lineages. In this review, we discuss the emerging proposals for how the flavonoid pathway may have evolved and diversified. This article is part of the theme issue 'The evolution of plant metabolism'. [ABSTRACT FROM AUTHOR]

This study presents a stochastic model of seed dispersal based on a branching random walk (BRW) framework, incorporating both homogeneous and non-homogeneous Poisson point processes (PPP). Building on the model introduced by Coletti et al. (2023), we examine the effects of habitat reduction on seed dispersal dynamics. We analyze the phase transition behavior of the BRW model under varying conditions of habitat fragmentation, focusing on how these conditions influence the critical dispersal rate. Specifically, we study a BRW on the real line with a non-homogeneous PPP driven by a log-normal density, constrained between spatial barriers. Our simulations localize the critical dispersal rate with respect to barrier positions and compare this dependence between homogeneous and non-homogeneous models. [ABSTRACT FROM AUTHOR]

Seed dispersal by frugivores is a crucial step of the life cycle of most plants, influencing plant population and community dynamics. Although very important for most ecosystems, we are just beginning to understand which are the mechanisms driving frugivore‐mediated seed dispersal. Most studies identifying the drivers of seed dispersal use interaction frequency as a proxy for estimating seed dispersal success, rather than looking at the functional outcomes of those interactions (e.g., contributions to successful seed germination). A valuable tool to link plant–frugivore interactions to seed dispersal success is the seed dispersal effectiveness (SDE) framework, which accounts for the quantity and quality components of seed dispersal. We evaluated which mechanisms, including morphological traits, trait matching and phenological overlap of interacting species, as well as degree of frugivory and feeding behaviour of frugivores, influenced the quantity (interaction frequency and number of seeds dispersed per visit) and quality (seed germination after gut passage) components of SDE. To this end, we combined three methods (focal observations, mist‐netting and camera traps) to sample interactions between plants, birds and mammals in a species‐rich community of Cerrado in southeastern Brazil. We recorded 590 pairwise interactions between 34 plants and 49 frugivores. We found that phenological overlap among interacting species explained most of the variation in interaction frequencies. Trait matching affected the number of seeds dispersed per visit more for gulpers than mashers and peckers, and frugivore body mass and seed sizes positively affected seed germination. Finally, interaction frequencies had a stronger contribution to SDE, compared with the number of seeds dispersed per visit and seed germination, indicating an indirect effect of phenological overlap on SDE. Synthesis. We found that highly abundant plant–frugivore species with the most overlap in their phenologies also yield the highest values of SDE, suggesting that phenological overlap was the most important driver of SDE in this hyperdiverse community. However, the number of seeds dispersed per visit also influenced SDE and seed germination was species‐specific, suggesting that estimating SDE at the community level is necessary to understand how communities work, and the current and future challenges they face. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Understanding the factors influencing how fast populations can spread across the landscape will be crucial as species ranges shift due to climate change. While the role of abiotic factors in determining expansion speed has been well studied in theory and empirical research, how competition impacts speed has received far less attention. Here, we investigated how seed dispersal distances change in response to competition and how these changes to distributions of dispersed seeds impact expansion speed. We dispersed four genotypes of the annual plant Arabidopsis thaliana with variation in life history traits into greenhouse mesocosms of either empty habitat or habitat containing the annual grass competitor, Lolium multiflorum. We found that competition decreased both mean and maximum dispersal distance. We then built a simulation model of range expansion with experimental data from this and a prior experiment to explore whether competition slows species expansions primarily through decreasing dispersal or fecundity. We found that competition primarily slows expansion speed through decreases in dispersal, but that when competition impacts both dispersal and fecundity, expansions slow more than with dispersal alone. The genotype with traits associated with longer distance dispersal was the most affected by competition in both experimental dispersal and simulations. This research suggests that not only does competition slow range expansions through decreases in both fecundity and dispersal, but that there may be consequences for evolutionary processes at the leading edge. [ABSTRACT FROM AUTHOR]

An examination of the dynamics of seed markets in Bihar, India, reveals a paradox—despite an influx of wheat varieties bred by public and private sectors and the proliferation of seed market networks in rural villages, older wheat varieties remain prevalent—necessitating a thorough investigation of the seed distribution system. Unlike most empirical studies that examine the adoption of new and improved crop varieties from a farmer's perspective, our study shifts the focus to the seed supply side. We analyse data collected from 200 private seed dealers who cater to the needs of over 163,000 farmers spread across 10 districts in Bihar. We use descriptive statistics alongside dealer-level and varietal-level regression models to examine the relationship between seed sales and varietal age. Findings indicate that the number of varieties available with a dealer (varietal richness) is positively associated with the number of seed buyers (dealer's reach) and the total quantity of seeds sold. Private varieties are in demand despite their higher prices. Dealer-level models showed that varietal age affects neither the reach nor the sales, allowing older public-sector varieties to coexist with more recent private-sector ones. However, the varietal-level regression models show that dealers rank the new varieties higher as the ones being sold more. To explore the potential of private seed markets to reduce the proliferation of old wheat varieties that are more susceptible to evolving biotic and abiotic stress factors, we recommend strengthening the varietal registration and seed certification processes, implementing better seed traceability systems, and fostering public–private partnerships in variety development and seed dissemination. Investing in market experiments to incentivize seed dealers to engage in quality assurance can help refine strategies and ensure efficient and inclusive dissemination of promising wheat varieties. [ABSTRACT FROM AUTHOR]

In boreal streams, restoration after channelization typically consists of increasing instream geomorphic complexity with no other active restoration measures (e.g. planting) as it mainly targets fish. Unsurprisingly, this restoration fails to restore riparian vegetation within the time frames needed to meet biodiversity goals. To understand the potential role of dispersal and seed banks in the poor restoration results, we compared deposition patterns from a seed release experiment conducted during spring flood and summer low flow conditions to seed bank‐ and vegetation composition. The experiment was conducted across seven boreal streams, each differing in time since restoration (0–22 years). We found that seed deposition increased due to low flow and local flow obstruction, suggesting the importance of instream boulders. Locations where there was a high deposition likelihood in our seed release experiment had higher Shannon diversity compared to locations with a low seed deposition likelihood. Riparian vegetation composition is related to flow obstruction, while seed bank species composition is correlated to spring flood seed deposition. In general, the sampled riparian seed banks contained few seeds and species. We therefore conclude that (1) restoration of hydrogeomorphic complexity (especially instream boulders) can enhance seed deposition with some effects on species composition of the vegetation and seed bank diversity, and (2) the importance of these generally species poor seed banks for the return of species after restoration boreal streams is questionable. Other (active) methods or more time may therefore be needed to meet biodiversity goals within riparian vegetation restoration. [ABSTRACT FROM AUTHOR]

Berries are a staple of bear diets during late summer and fall in the southern Rocky Mountains, enabling bears to build up fat reserves and prepare to enter torpor during winter. In turn, bears can benefit fruiting shrubs through dispersal of their seeds. Bears are highly mobile species and seed passage through their guts (endozoochory) can influence seed germination in three ways: deinhibition (removal of germination inhibiting compounds), scarification (mechanical or chemical alteration) and fertilization (enhancement of germination from increased nutrients). We conducted a germination experiment to assess the ways each mechanism of bear endozoochory affects germination success of huckleberry (Vaccinium membranaceum.) in the southern Canadian Rocky Mountains. The potential for bears to act as long-distance seed dispersers was also investigated, using a combination of available literature on bear gut retention times and movement data of 74 GPS radio-collared grizzly bears. Deinhibition had a positive significant impact (28.5% germination for the Seeds from Berry treatment compared to 0.2% for Whole Berry at 60 days), while scarification and fertilization did not have detectable positive effects on huckleberry germination success. These results suggest that the removing germination-inhibiting compounds in berry pulp is the primary mechanism through which endozoochory can increase germination in huckleberry seed. We estimated that 50% of the seeds defecated by bears in the region are dispersed 1.1 km away from feeding places (and up to 7 km). The surfaces covered by the seed shadow was up to 149.6 km2, demonstrating that bears can act as effective vectors of seeds over long distances. Endozoochory bolsters the germination success of seeds from fruiting shrubs, and enables seeds to spread to new locations using bears as dispersal agents. Development, resource extraction, and climate change may disrupt the beneficial relationship between bears and huckleberries, where huckleberries help bears gain fat, and bears help spread huckleberry seeds—a process that may become increasingly important as climate change alters habitats. [ABSTRACT FROM AUTHOR]

Vertical seed dispersal, involving seed movement to higher or lower elevations, plays a vital role in plant adaptation to rising temperatures. However, its assessment has been limited owing to labor‐intensive processes. A recently developed method exploits the negative correlation between elevation and seed oxygen isotope ratios (18O/16O; hereafter δ18O) for efficient evaluation of vertical seed dispersal. Nevertheless, it remains unclear whether this method is suitable for conifers and whether plant size and age introduce noise into δ18O values, which would affect vertical seed dispersal estimations. In this study, we investigated the association between elevation and seed δ18O values of Japanese larch (Larix kaempferi) and explored the relationship among these oxygen isotope ratios, tree height, diameter at breast height (DBH), and age. Notably, we found a negative correlation between elevation and seed δ18O values of L. kaempferi but failed to detect any influence of tree height, DBH, and age on these oxygen isotope ratios. These findings suggest this method's potential for accurately estimating vertical seed dispersal across diverse plant lineages. [ABSTRACT FROM AUTHOR]

Antagonist and mutualist organisms mediate the long‐standing, classical Janzen‐Connell effects and yet they are rarely investigated, especially when they share plant species hosts. Here, we propose that plant species create an “antagonists‐ and mutualist‐scape” which, coupled with seed dispersal mechanisms, will govern the relative survival rates of juveniles within the landscape and influence their later life stages. We combined data on fully stem mapped plots of woody plant species in two Mediterranean forests (Mixed Forest of Segura [MFS] and Mixed Forest of Jaen [MFJ]) with data on the associated communities of leaf epiphytic fungi, leaf pathogens, sap‐sucking insects and chewer insects hosted by each woody plant species. This allowed us to indirectly test the Janzen‐Connell hypothesis by investigating the placement of plant species with contrasting seed dispersal mechanisms (fleshy fruited vs. dry‐fruited plant) within the antagonists‐ and mutualist‐scapes. More specifically, we determined the degree of host‐specificity of plant‐associated organisms and defined the antagonist‐ or mutualist‐scapes for focal plants as the mean number of antagonist‐ or mutualist species the focal plant shares with its (sapling or adult) plant neighbours, respectively. We then applied multivariate spatial point pattern analysis to test whether saplings and adults of the focal species tended to be located in favourable sites of the antagonist‐scapes (i.e. were neighboured by fewer antagonist species than expected) or were distributed independently of the antagonist‐scapes. A substantial proportion of organisms was associated with more than one plant species, with organisms at MFJ being more “host‐specific” than organisms at MFS. Our spatial analyses revealed spatial patterns that differed strongly between fleshy‐fruited and dry‐fruited species and were, in most cases, consistent with our expectations. For example, saplings of dry‐fruited species were placed in favourable sites in the saplings antagonist‐scapes, whereas saplings of fleshy‐fruited species were independently placed with respect to the saplings antagonist‐scapes. Our results show how the placement of plant species within the antagonist‐scapes changes during the ontogeny, and how this is influenced by Janzen‐Connell effects and the seed dispersal mechanisms. We provide a new approach and indications about the importance of generalist antagonists and mutualists as drivers of the spatial assembly of plant communities. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

This is the first documented instance of Sri Lanka's endemic Macaca sinica (toque macaque) foraging on invasive Annona glabra (pond apple). We observed a troop of toque macaques (∼15) consuming A. glabra in a mangrove forest in Negombo lagoon in western Sri Lanka. This behaviour highlights the need to understand species interactions in the design of effective invasive species interventions for mangrove management. [ABSTRACT FROM AUTHOR]

This study investigates the effects of seasonal changes in vegetation productivity on olive baboon feeding behavior in a protected Guinea savannah (Kainji Lake National Park). Over two consecutive years (2017 and 2018), observations were conducted both during the wet and dry seasons using a scan sampling method. Results revealed that olive baboons consumed 34 plant species belonging to 20 families, with 28 species in the wet season and 12 in the dry season. A total of 922 feeding events were recorded in the wet season and 621 in the dry season, indicating significant seasonal variation. Fruits were the preferred food item, especially in the dry season, followed by animal matter, seeds, leaves, and subterranean food. Interestingly, baboons also consumed tree bark regardless of season. In addition, their consumption of fruits (in both seasons) and seeds (in the dry season) highlights their ecological role in seed dispersal and plant regeneration within the park. To sustain baboon (and all non-human primates) conservation efforts within the park, it's important to maintain a high diversity and abundance of native fruit trees throughout the year. This study highlights the importance of understanding how seasonal changes in vegetation affect olive baboon feeding behavior for effective park management and biodiversity conservation. [ABSTRACT FROM AUTHOR]

When non‐native species invade ecosystems, coevolved plant–animal interactions and associated ecological functions are altered, often to the detriment of local biodiversity. While mutualistic interactions can benefit from—and assist with—ecological restoration through the removal of non‐native species, community‐level changes in antagonistic interactions due to restoration are less well understood. Insect seed predators provide important ecosystem functions, but can also have antagonistic effects through pre‐dispersal seed predation which can cause fruit abortion or premature fruit drop, potentially affecting plant community composition.Here, we used a network approach and data on trophic interactions from a large‐scale field experiment to investigate the differences in insect seed predator communities between native restored sites (where non‐native plants were removed) and unrestored sites dominated by non‐native plants on the island of Mahé, Seychelles.Restored sites contained more individuals and species of seed predators (up by 81% and 50% respectively), and experienced a greater predation intensity (1.06 ± 0.53 vs. 0.27 ± 0.09), and predator specialisation compared to unrestored sites. The proportion of predated samples was similar between treatments (~14%). Beta diversity, measured as species and interaction turnover, increased at restored sites.Synthesis and applications: Our findings imply that vegetation restoration generates marked biodiversity benefits on native seed predator communities and their interactions. However, removing non‐native plants did not result in the elimination of non‐native seed predators, which might require targeted control measures. Our results highlight the importance of considering the effects of restoration on antagonistic interactions, in addition to those reported for pollination and seed dispersal services. Management practices should aim to control plant invasions for the conservation of native plant communities that serve as resources and refugia both for mutualists (e.g., seed dispersers and pollinators) and native insect seed‐predator antagonists, both of which benefit native ecosystem function. [ABSTRACT FROM AUTHOR]

Premise of research. Seed dispersal has an essential role in structuring plant populations. Most studies of effects of variation of wind-dispersed diaspore characteristics on dispersal capacity have focused on single-seeded fruits. However, effects of seed number on dispersal capacity of multiseeded fruit diaspores have rarely been explored. We assessed the relationships between seed number and fruit and seed packaging characteristics in multiseeded fruits of Cercis canadensis and how these influence their dispersal potential. Methodology. We performed indoor dispersal experiments with fruits in still air to determine how variability in seed number and mass affected their rates of descent and dispersal distances. Pivotal results. Few-seeded fruits had an asymmetrical distribution of seeds, with more seeds being situated at the bases than at the tips of fruits, whereas seeds were more evenly distributed in many-seeded fruits. Few-seeded fruits had significantly higher rates of descent and dispersed significantly shorter distances compared with many-seeded fruits, despite the former having lower wing loading values. We determined that redbud fruits could be grouped into two aerodynamic types, with few-seeded fruits behaving as rolling autogyros with tight helical trajectories and many-seeded fruits behaving as rolling autogyros with broad helical flight paths. Conclusions. Our findings suggest that differences in seed number and internal seed weight distribution within redbud fruits have variable effects on diaspore flight behavior. Future studies of wind dispersal of multiseeded diaspores will need to account for within-fruit variation in the locations, sizes, and numbers of seeds. [ABSTRACT FROM AUTHOR]

Social Impact Statement: Gingko biloba is an iconic tree with a surprising connection to the SARS and Covid viruses that have impacted human health since 2003. Natural history studies on the ecology of Gingko seed dispersal by Carnivoran scavengers in Asia over the past 30 plus years have elucidated the deep evolutionary history that not only makes these animals effective at spreading seeds but also predisposes them to become intermediate hosts for spreading diseases to humans. Understanding the behavioral traits that underlie these kinds of plant–animal interactions has the potential to help people limit the spread of future spillover diseases. Summary: Raccoon dogs and masked palm civets are Carnivoran scavengers native to Eastern Asia that have been documented feeding on the malodorous sarcotesta of Ginkgo biloba seeds and effectively dispersing the hard nuts they contain. Research has shown that their immune systems are genetically enhanced to protect them from the disease‐causing organisms they might pick up from their omnivorous diets that include live and dead animals. Both species are farmed for fur and meat across China and, up until recently, were commonly sold in "wet" markets. Research has determined that the palm civet played a role in spreading the SARS virus to humans in 2003 and that the raccoon dog may have played a similar role in spreading Covid in Wuhan in 2019, although this has not been proven. In areas where Ginkgo is cultivated, there are numerous internet reports of Carnivorans feeding on its seeds indicating that its dispersal strategy of attracting scavengers by mimicking the smell of carrion is adaptive and effective. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: This study illuminates the underappreciated role of invertebrates in seed dispersal, extending beyond the well‐documented contributions of ants. Focusing on Monotropastrum humile (銀竜草 [silver dragon plant] or 水晶蘭 [crystal orchid]), a non‐photosynthetic plant known for its minuscule, dust‐like seeds, the present research uncovers their seed dispersal roles of woodlice and earwigs in Japan. Remarkably, these invertebrates include the smallest known endozoochorous seed dispersers. Summary: Endozoochory, or internal seed dispersal through the digestive tracts of animals, has been less studied in invertebrates compared with vertebrates. Nonetheless, endozoochory is plausible whenever seeds are small enough for ingestion by frugivorous animals, suggesting a potential role for invertebrates in seed dispersal, especially for plants with minute seeds.Monotropastrum humile (Ericaceae), characterized by its fleshy fruits and dust‐like seeds, is known to utilize invertebrate agents such as camel crickets and cockroaches for seed dispersal. Here, we investigate this seed dispersal mechanism using time‐lapse photography, feeding experiments, and seed coat anatomy analysis, particularly focusing on interactions among undocumented invertebrate internal seed dispersers.Field observations indicated that in the studied population, M. humile fruits were primarily consumed by camel crickets, woodlice, and earwigs. Their effectiveness as seed dispersers varied, with camel crickets primarily acting as dispersers, whereas earwigs and woodlice were more inclined toward seed predation. Nonetheless, some seeds defecated by earwigs and woodlice remained intact, suggesting that they could also function as dispersal agents.The woodlouse Porcellio scaber is now recognized as the world's smallest internal seed dispersal agent. Combined with earlier discoveries, such as seed dispersal by camel crickets, cockroaches, and ants, and the fact that P. scaber is an exotic species in the study site, M. humile likely depends on a broad spectrum of local invertebrates. The engagement of multiple invertebrate dispersers may enhance seed dispersal across diverse habitats. [ABSTRACT FROM AUTHOR]

Summary: Amphicarpy is an unusual trait where two fruit types develop on the same plant: one above and the other belowground. This trait is not found in conventional model species. Therefore, its development and molecular genetics remain under‐studied. Here, we establish the allooctoploid Cardamine chenopodiifolia as an emerging experimental system to study amphicarpy.We characterized C. chenopodiifolia development, focusing on differences in morphology and cell wall histochemistry between above‐ and belowground fruit. We generated a reference transcriptome with PacBio full‐length transcript sequencing and analysed differential gene expression between above‐ and belowground fruit valves.Cardamine chenopodiifolia has two contrasting modes of seed dispersal. The main shoot fails to bolt and initiates floral primordia that grow underground where they self‐pollinate and set seed. By contrast, axillary shoots bolt and develop exploding seed pods aboveground. Morphological differences between aerial explosive fruit and subterranean nonexplosive fruit were reflected in a large number of differentially regulated genes involved in photosynthesis, secondary cell wall formation and defence responses.Tools established in C. chenopodiifolia, such as a reference transcriptome, draft genome assembly and stable plant transformation, pave the way to study amphicarpy and trait evolution via allopolyploidy. [ABSTRACT FROM AUTHOR]

Tritaxis kurnoolensis, a small tree of the Euphorbiaceae family, is endemic to a valley within the Sullavai Sandstone plateau in close proximity to the Paleru Reservoir (Owk dam). The species is a narrow endemic. No documented sightings of this species have been recorded beyond the type locality since its description in 1994 by Venkataraju & Pullaiah as Dimorphocalyx kurnoolensis from the Nandyal District of Andhra Pradesh. In this study, the authors applied the grid method for quantification and subjected the species to a meticulous analysis aligning with IUCN Red List Criteria. The distribution was found to be restricted due to habitat (valley) fragmentation, reservoir which is arresting seed dispersal, and destruction caused by tunnel construction civil works. The area of occupancy (AOO) at 16 km² and the extent of occurrence (EOO) at 0.474 km², were systematically computed using GeoCAT. The species is assessed here using the Red List methodology for evaluating extinction risk. Based on its AOO, EOO, and population size, it has been classified as Critically Endangered. [ABSTRACT FROM AUTHOR]

The intrinsic ability of plants to face environmental diel changes is paramount for flowering and interactions with pollinators and herbivores. Surprisingly, despite the commendable research efforts on the ecology and evolution of fruit‐frugivore interactions, very little is known about how fruit ripening and dropping vary throughout 24‐h cycle. Even less is known about the potential consequences of circadian fruit phenology on plant interactions with mutualistic and antagonistic frugivores. We illustrate for the first time how the circadian pattern of fleshy fruit dropping and its matching/mismatching with the diel activity of functionally diverse frugivores (fruit/seed predators, seed dispersers, pulp feeders) can drive the outcome of complex multispecies plant‐frugivore interactions. To that end, we used camera trapping to quantify the circadian fruit dropping of a mammal‐dispersed tree, Pyrus bourgaeana, and the diel activity patterns of its functionally diverse vertebrate frugivores during two fruiting seasons in two tree populations of Mediterranean Spain. Using a large data set (20,878 frugivore visits and 701 fruit‐dropping records), we evaluate the adaptive hypothesis that the circadian pattern of fruit dropping will match the diel activity of seed dispersers rather than that of fruit/seed predators. Fruit dropping during daytime doubled that at night‐time, being considerably consistent across and within seasons, study sites and individual trees. Specifically, overlaps between circadian patterns of fruit dropping across and within seasons (0.83 and 0.84 ± 0.02, respectively), study sites (0.95) and individual trees (0.68 ± 0.01) were always high. Whereas seed dispersers (mammalian carnivores) were mostly nocturnal, the most frequent fruit/seed predators (cervids) were mostly diurnal. Consequently, and contrary to our expectations, circadian fruit dropping was more aligned with the diel activity of overabundant fruit/seed predators than with that of carnivore seed dispersers. Our study illustrates how quantifying the circadian patterns of fruit dropping, the diel activity of functionally diverse frugivores, and the matching/mismatching between both patterns can contribute to a better understanding of multispecies plant‐frugivore interactions. Circadian fruiting phenology is an overlooked key attribute for most tropical and temperate fruiting plants, which patterns, mechanisms and outcomes must be fully investigated. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Invasive species are major drivers of global ecosystem change. They often displace native species through competitive exclusion, creating novel species interactions. These interactions can lead to ecological cascades, where the presence of one invasive species enhances the fitness of another. Despite this, the mechanisms that underpin these mutualistic interactions and promote secondary invasions remain poorly understood. We assessed how the introduction of the invasive Argentine ant (Linepithema humile) alters mutualistic interactions within the recipient community, enhancing the dispersal and fitness of species of a secondary invasive plant genus (Acacia spp.). Our study examines these interactions at the community, individual species, and trait levels for a range of native and non‐native ant and plant species. Specifically, we aimed to investigate the direct and indirect effects of L. humile on seed dispersal mutualisms. We found that in L. humile invaded locations, seeds of the invasive Acacia plant species were approximately three times more likely to be dispersed than seeds of native endemic plant species. This preference is driven by indirect changes in the community structure of native seed‐dispersing ants, rather than direct interactions between the invasive ant and plant species. Moreover, we found that native ant species that co‐exist with L. humile, such as Tetramorium sericeiventre, respond to a narrower range of seed traits—traits which the invasive Acacia seeds possess. Our findings suggest that the invasion of L. humile has cascading effects on ant‐plant mutualisms, potentially increasing community permeability to secondary invasions. These results highlight that the impact of invaders like the Argentine ant may be greater than initially perceived, driving losses in both biological and functional plant diversity. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Premise Methods Results Conclusions Volatile emissions from flowers and fruits play a key role in signalling to animals responsible for pollination and seed dispersal. Here, we investigated the pollination biology and chemical ecology of reproduction in Apodolirion buchananii, an African amaryllid that flowers in a leafless state soon after grassland vegetation is burnt in the dry late‐winter season.Pollinators were identified through field collection and pollen loads were quantified. Floral traits including spectral reflectance and scent chemistry were documented. Bioassays using cup traps were used to test the function of floral volatiles. Fruiting biology was investigated using controlled hand‐pollination experiments and chemical analysis of fruit scent. Seed germination was scored in greenhouse trials. Seed dispersal was monitored using observations and camera trapping.The sweetly scented white flowers of A. buchananii are pollen‐rewarding and pollinated mainly by a diverse assemblage of bees. Cup‐trap experiments demonstrated that pollinators are attracted to phenylacetaldehyde, the dominant volatile in the floral scent. Plants are shown to be self‐incompatible, and the fleshy fruits were found to emerge from the soil six months after pollination during the peak of the summer rains. Fruits emit a diverse blend of aliphatic and aromatic esters and contain large fleshy recalcitrant seeds which germinate within days of fruits splitting open. Seed dispersal by ants was recorded.This first account of the reproductive biology of a species in the genus Apodolirion highlights an outcrossing mating system involving bees attracted to color and scent as well as the unusual fruiting biology and ant‐mediated system of seed dispersal. [ABSTRACT FROM AUTHOR]

Understanding how biotic interactions shape ecosystems and impact their functioning, resilience and biodiversity has been a sustained research priority in ecology. Yet, traditional assessments of ecological complexity typically focus on species-species interactions that mediate a particular function (e.g., pollination), overlooking both the synergistic effect that multiple functions might develop as well as the resulting species-function participation patterns that emerge in ecosystems that harbor multiple ecological functions. Here we propose a mathematical framework that integrates various types of biotic interactions observed between different species. Its application to recently collected data of an islet ecosystem—reporting 1537 interactions between 691 plants, animals and fungi across six different functions (pollination, herbivory, seed dispersal, decomposition, nutrient uptake, and fungal pathogenicity)—unveils a non-random, nested structure in the way plant species participate across different functions. The framework further allows us to identify a ranking of species and functions, where woody shrubs and fungal decomposition emerge as keystone actors whose removal have a larger-than-random effect on secondary extinctions. The dual insight—from species and functional perspectives—offered by the framework opens the door to a richer quantification of ecosystem complexity and to better calibrate the influence of multifunctionality on ecosystem functioning and biodiversity. Studies of species interactions tend to focus on single ecological functions. Here, the authors show that plant species tend to participate across different ecological functions in a non-random, nested structure, and some species and functions emerge as unexpected keystone actors of the multifunctional ecosystem. [ABSTRACT FROM AUTHOR]

Three‐dimensional (3D) vegetation structure influences animal movements and, consequently, ecosystem functions. Animals disperse the seeds of 60%–90% of trees in tropical rainforests, which are among the most structurally complex ecosystems on Earth. Here, we investigated how 3D rainforest structure influences the movements of large, frugivorous birds and resulting spatial patterns of seed dispersal. We GPS‐tracked white‐thighed (Bycanistes albotibialis) and black‐casqued hornbills (Ceratogymna atrata) in a study area surveyed by light detection and ranging (LiDAR) in southern Cameroon. We found that both species preferred areas of greater canopy height and white‐thighed hornbill preferred areas of greater vertical complexity. In addition, 33% of the hornbills preferred areas close to canopy gaps, while 16.7% and 27.8% avoided large and small gaps, respectively. White‐thighed hornbills avoided swamp habitats, while black‐casqued increased their preference for swamps during the hottest temperatures. We mapped spatial probabilities of seed dispersal by hornbills, showing that 3D structural attributes shape this ecological process by influencing hornbill behaviour. These results provide evidence of a possible feedback loop between rainforest vegetation structure and seed dispersal by animals. Interactions between seed dispersers and vegetation structure described here are essential for understanding ecosystem functions in tropical rainforests and critical for predicting how rainforests respond to anthropogenic impacts. [ABSTRACT FROM AUTHOR]

Many plants exhibit a canopy seed bank, where seeds persist within the canopy for prolonged periods, gradually descending over time and potentially influencing seed predation and animal‐mediated dispersal. However, the impact of delayed seed drop on animal predation and seed dispersal remains unclear. We used Chinese Armand pine seeds to simulate delayed seed drop of the canopy seed bank by releasing 7800 pine seeds in both winter and the following summer over 2 years, tracking their fates to investigate its effect on seed predation and dispersal by rodents in a pine plantation in southwest China. Results showed significant seasonal differences in seed fate. In summer, seeds experienced higher predation rates (62.08% vs 3.80% in winter) and lower scatter‐hoarding rates (4.18% vs 15.40% in winter). Additionally, seeds in summer were dispersed farther (4.20 m vs. 3.56 m in winter) and primarily formed single‐seed caches, as opposed to multi‐seed caches in winter. Although delayed seed drop increased immediate predation risks, favorable summer conditions allowed for rapid germination, reducing long‐term exposure to predation. In conclusion, while delayed seed drop increases immediate predation risks and reduces caching, it concurrently enhances dispersal distances and reduces cache size. [ABSTRACT FROM AUTHOR]

Different convergent evolutionary strategies adopted by angiosperm fruits lead to diverse functional seed dispersal units. Dry dehiscent fruits are a common type of fruit, characterized by their lack of fleshy pericarp and the release of seeds at maturity through openings (dehiscence zones, DZs) in their structure. In previous decades, a set of core players in DZ formation have been intensively characterized in Arabidopsis and integrated in a gene regulatory network (GRN) that explains the morphogenesis of these tissues. In this work, we compile all the experimental data available to date to build a discrete Boolean model as a mechanistic approach to validate the network and, if needed, to identify missing components of the GRN and/or propose new hypothetical regulatory interactions, but also to provide a new formal framework to feed further work in Brassicaceae fruit development and the evolution of seed dispersal mechanisms. Hence, by means of exhaustive in-silico validations and experimental evidence, we are able to incorporate both the NO TRANSMITTING TRACT (NTT) transcription factor as a new additional node, and a new set of regulatory hypothetical rules to uncover the dynamics of Arabidopsis DZ specification. [ABSTRACT FROM AUTHOR]

Seed dispersal is crucial for ecosystem persistence, especially in fragmented landscapes, such as those common in Europe. Ongoing defaunation might compromise effective seed dispersal, but the conservation status of pairwise interactions remains unknown. With a literature review, we reconstructed the first European-wide seed dispersal network and evaluated the conservation status of interactions by assessing each interacting partner's IUCN (International Union for Conservation of Nature) conservation status and population trends. We found that a third of the disperser species and interactions face potential extinction and that 30% of the plant species have most of their dispersers threatened or declining. Our study reveals a developing seed dispersal crisis in Europe and highlights large knowledge gaps regarding the dispersers and conservation status of zoochorous plants, urging further scrutiny and action to conserve the seed dispersal service. [ABSTRACT FROM AUTHOR]

Frugivory and seed dispersal are fundamental ecological interactions influencing plant population dynamics and distribution. Still, understanding how the ingestion of seeds by fruit-eating animals affects seedling emergence performance remains poorly documented. Seed dispersal through animal ingestion can either promote or hinder germination. In this study, we assessed how seed ingestion by Saguinus bicolor, a critically endangered primate from the Brazilian Amazon, affects germination rate and germinability. As primate seed ingestion often improves seed germination, we predicted that germination rate and germinability would be higher in seeds defecated by the tamarins if compared to hand-extracted seeds. Of the 23 species, five did not germinated in either the control or gut-passage treatments. Among the ones that germinated, nine had an average increase in germinability, two decreased in germinability, and seven had a neutral effect. The germination rate increased in four species, reduced in eight species and had a neutral effect in six of the species. Most of the seeds that passed through the tamarins' digestive tract successfully germinated, demonstrating that seed ingestion by pied tamarins can benefit the plant populations by dispersing viable seeds through the landscape. [ABSTRACT FROM AUTHOR]

The ovules or seeds (fertilized ovules) with wings are widespread and especially important for wind dispersal. However, the earliest ovules in the Famennian of the Late Devonian are rarely known about the dispersal syndrome and usually surrounded by a cupule. From Xinhang, Anhui, China, we now report a new taxon of Famennian ovules, Alasemenia tria gen. et sp. nov. Each ovule of this taxon possesses three integumentary wings evidently extending outwards, folding inwards along abaxial side and enclosing most part of nucellus. The ovule is borne terminally on smooth dichotomous branches and lacks a cupule. Alasemenia suggests that the integuments of the earliest ovules without a cupule evolved functions in probable photosynthetic nutrition and wind dispersal. It indicates that the seed wing originated earlier than other wind dispersal mechanisms such as seed plume and pappus, and that three- or four-winged seeds were followed by seeds with less wings. Mathematical analysis shows that three-winged seeds are more adapted to wind dispersal than seeds with one, two or four wings under the same condition. [ABSTRACT FROM AUTHOR]

The use of propagules collected in ecotonal regions for restoration purposes is challenging because of the mix of species from different vegetation types and reproductive phenological variability. We used a database of the Xingu Seed Network in Brazil, which contains data on 139 native tree species for 8 years (2011–2018) in the Cerrado–Amazonia transition zone, to answer three questions: (1) What is the spatio‐temporal variability in the seed dispersal of tree species, and how does it relate to the species' preferential habitat? (2) Is there a relationship between the seed dispersal period and climate variables? (3) Is the frequency of tree species with different dispersal syndromes equally distributed among biomes and seed‐size classes? Independent of their preferred ecosystem (Amazonia or Cerrado), some species showed substantial spatio asynchrony in fruit dispersal, extending the dispersal period at a regional scale. The seed dispersal period was strongly correlated (rs > 0.6) with precipitation and minimum or maximum air temperature in 41% (n = 57) of the studied species. We showed that three‐quarters of the species (n = 105) dispersed seeds in the late dry and early rainy periods, with little variation among dispersal syndromes. Our findings will enhance the effectiveness of restoration initiatives by increasing the accuracy of predictions of the location and time for collecting seeds in the extensive Cerrado–Amazonia transition zone. [ABSTRACT FROM AUTHOR]

Background and Aims The size and shape of reproductive structures is especially relevant in evolution because these characters are directly related to the capacity for pollination and seed dispersal, a process that plays a basic role in evolutionary patterns. The evolutionary trajectories of reproductive phenotypes in gymnosperms have received special attention in terms of pollination and innovations related to the emergence of the spermatophytes. However, variability of reproductive structures, evolutionary trends and the role of environment in the evolution of cycad species have not been well documented and explored. This study considered this topic under an explicitly phylogenetic and evolutionary approach that included a broad sampling of reproductive structures in the genus Ceratozamia. Methods We sampled 1400 individuals of 36 Ceratozamia species to explore the evolutionary pattern and identify and evaluate factors that potentially drove their evolution. We analysed characters for both pollen and ovulate strobili within a phylogenetic framework using different methods and characters (i.e. molecular and both quantitative and qualitative morphological) to infer phylogenetic relationships. Using this phylogenetic framework, evolutionary models of trait evolution for strobilar size were evaluated. In addition, quantitative morphological variation and its relation to environmental variables across species were analysed. Key Results We found contrasting phylogenetic signals between characters of pollen and ovulate strobili. These structures exhibited high morphological disparity in several characters related to size. Results of analyses of evolutionary trajectories suggested a stabilizing selection model. With regard to phenotype–environment, the analysis produced mixed results and differences for groups in the vegetation type where the species occur; however, a positive relationship with climatic variables was found. Conclusions The integrated approach synthesized reproductive phenotypic variation with current phylogenetic hypotheses and provided explicit statements of character evolution. The characters of volume for ovulate strobili were the most informative, and could provide a reference for further study of the evolutionary complexity in Ceratozamia. Finally, heterogeneous environments, which are under changing weather conditions, promote variability of reproductive structures. [ABSTRACT FROM AUTHOR]

We present a combination of laboratory experiments and computational fluid dynamics (CFD) simulations to understand the wind-induced drag force and drag coefficient for Saccharum contortum seeds. Seed drop experiments indicate that the settling fall velocities of hair-equipped seeds are within 1–2 m/s, compared to 2.34 times higher settling fall velocity of the seed without hairs. The experimental data illustrate a power-law relationship between drag coefficient ( C d ) and Reynolds number (Re) under the free fall condition: C d ∼ R e − 1.1 . CFD simulations show that both viscous and pressure drag force components are important in contributing to wind drag. The presence of hairs substantially increases pressure drag, and its relative importance depends on hair number and orientation. Seed morphology including hair number and orientation influences the drag coefficient under different flow directions relatively to the seed body. The lower drag coefficient observed with crossflow wind compared to free fall suggests that seeds encounter less air resistance while drifting horizontally in the wind, favoring extended flying time and distance. Based on the varying drag coefficients under different conditions, we propose the incorporation of varying drag coefficients in future wind-driven seed dispersal models. [ABSTRACT FROM AUTHOR]

Premise: Seed dispersal is a critical process impacting individual plants and their communities. Plants have evolved numerous strategies and structures to disperse their seeds, but the evolutionary drivers of this diversity remain poorly understood in most lineages. We tested the hypothesis that the evolution of wind dispersal traits within the melicgrasses (Poaceae: Meliceae Link ex Endl.) was correlated with occupation of open and disturbed habitats. Methods: To evaluate wind dispersal potential, we collected seed dispersal structures (diaspores) from 24 melicgrass species and measured falling velocity and estimated dispersal distances. Species' affinity for open and disturbed habitats were recorded using georeferenced occurrence records and land cover maps. To test whether habitat preference and dispersal traits were correlated, we used phylogenetically informed multilevel models. Results: Melicgrasses display several distinct morphologies associated with wind dispersal, suggesting likely convergence. Open habitat taxa had slower‐falling diaspores, consistent with increased wind dispersal potential. However, their shorter stature meant that dispersal distances, at a given wind speed, were not higher than those of their forest‐occupying relatives. Species with affinities for disturbed sites had slower‐falling diaspores and greater wind dispersal distances, largely explained by lighter diaspores. Conclusions: Our results are consistent with the hypothesized evolutionary relationship between habitat preference and dispersal strategy. However, phylogenetic inertia and other plant functions (e.g., water conservation) likely shaped dispersal trait evolution in melicgrasses. It remains unclear if dispersal trait changes were precipitated by or predated changing habitat preferences. Nevertheless, our study provides promising results and a framework for disentangling dispersal strategy evolution. [ABSTRACT FROM AUTHOR]

South American subtropical landscapes are dominated by open grasslands and mosaics of forest–grassland formations. Forests are often restricted to riverine margins with sharp forest–grassland ecotones. Understanding the mechanisms maintaining forest–grassland ecotones is important to anticipate the effects of changing climate and disturbance regimes on the extent of these biomes and the ecosystem services they provide.We used a combination of field surveys and long‐term field experiments to explore the mechanisms that explain tree cover expansion at the ecotone of riverine forests and grasslands in central Uruguay, within the South American Campos. We assessed the role of tree seed dispersal and seedling establishment limitations, and experimentally tested for the effects of cattle, nurse tree cover and grasses on the recruitment of forest and grassland tree species at the forest–grassland ecotone.We found that forest expansion depends on the interplay between cattle and nurse trees. Vachellia caven trees colonize the grassland successfully and facilitate the formation of forest patches by enhancing seed accumulation and seedling establishment of forest tree species. Surprisingly, grass cover had mostly positive effects on early seedling survival of forest tree seedlings. However, cattle limits tree seedling growth and survival, especially of forest tree species. This results in a nucleated vegetation pattern of tree patches that ultimately limits forest expansion.Synthesis and applications. Tree cover can potentially expand on the subtropical South American grasslands. Reductions in cattle densities and increases in rainfall levels associated with climate change could facilitate forest expansion in this region. [ABSTRACT FROM AUTHOR]

The downsizing of disperser assemblages by selective defaunation is a worldwide phenomenon thought to have important consequences in animal‐dispersed plants. Numerous large‐seeded Neotropical plants currently depend on the last megafaunal survivors, the large tapirs Tapirus spp., and medium‐sized frugivores. The extent to which medium frugivores are functionally equivalent to tapirs remains unresolved. We combined feeding trials, seed dispersal kernel modeling based on seed retention times and animal movement simulation (Levy walks), and germination experiments in a large‐seeded palm to assess the dispersal quality provided by the largest (tapirs) and two medium (foxes and howler monkeys) frugivore species in terms of dispersal distances and gut passage effects on germination. Tapirs retained the seeds in the gut for much longer (mean = 221 hours) than howlers (43 h) and foxes (22 h). Median dispersal distance by tapirs (1252 m) was 14 and 40 times larger than that by foxes (88 m) and howlers (31 m), respectively. The seed dispersal kernel of tapirs showed a 5th percentile value (291 m) larger than the 95th percentiles of foxes (285 m) and howlers (108 m). Manually depulped and gut‐passed seeds germinated in similar proportions, showing, respectively, 3.5 and 2.5–2.9 times higher values than intact fruits. Germination probability and seed viability decreased with retention time in howlers' and tapirs' gut, with howlers showing a steeper negative relationship. Such detrimental effect implies a trade‐off between germination success and dispersal distance. We conclude that tapirs may not play a unique role in germination enhancement but move seeds much further than medium frugivores, thus playing a critical role as long‐distance dispersers of many plants. This study provides important insights on palm–frugivore interactions and the potential consequences for large‐seeded plants of losing the last megafaunal representatives in the Neotropics. [ABSTRACT FROM AUTHOR]

The global loss of plant diversity is expected to have reverberating effects on other trophic levels, affecting the structure and functioning of ecosystems. To understand such effects, biodiversity–ecosystem function (BEF) experiments that manipulate tree diversity have been established around the world. In a BEF experiment carried out since 2016 in a seasonally dry tropical forest, we examined the effects of tree diversity, facilitation and density of trees with extrafloral nectaries on the abundance, richness, functional diversity and phylogenetic diversity of ground ants. Also, we used artificial seeds to test seed dispersal efficiency of ants within the experiment. Generalized linear mixed models (GLMM) showed that tree richness positively affects ant abundance, richness, functional diversity and phylogenetic diversity. Also, tree richness had a strong positive effect on the proportion of dispersed seeds, as well as their dispersal distance. Contrary to our expectations, facilitation and the number of trees with extrafloral nectaries did not affect ground ants and their functions. Our results indicate that the global impoverishment of tree communities can affect several dimensions of ant diversity and their ecosystem functions, including forest regeneration processes. [ABSTRACT FROM AUTHOR]

Seed dispersal by frugivorous animals is a key process for plant populations and communities. When frugivores consume fruits, seeds are temporarily retained inside their guts until seed deposition. Hence, information on retention times is essential to estimate seed‐dispersal distances. Although it is well known that retention times are affected by the body size of frugivores, there is an important knowledge gap on the effects of plant species traits, such as seed size and pulp content.Here, we comprehensively address whether and which plant traits affect seed retention times in frugivorous birds. On the one hand, we conducted a first set of experiments to assess variation in retention times among 31 plant species dispersed by a single bird species, and a second set to assess variation among five plant species dispersed by a guild of five frugivorous passerines. On the other hand, we conducted a literature review retrieving retention times for 231 interactions involving 155 plant species and 55 bird species from nine different avian orders.Seed size had negative effects on retention times at the three levels addressed in this study: the larger the seeds, the shorter the times. The effects of seed size were higher within a single bird species, intermediate for the small assemblage of five passerine species, and lower for all frugivorous birds included in the compilation. Notably, the effects of seed size on retention times were comparable to that of frugivore body size in Passeriformes. We analysed the effects of the pulp content on a single bird species, but these lacked predictive power. Importantly, the effects of seed size were indirect and mediated by the type of seed ejection (digestive processing): birds generally defecate smaller seeds and regurgitate the larger ones.We provide comprehensive evidence that retention times are intrinsically linked to plant traits and to frugivores' response to such traits, particularly to seed size and the type of seed ejection, respectively. Thus, our study unveils a source of interspecific variability in the capacity of plants to disperse at long distances. Moreover, we provide methodological improvements to trait‐based models that estimate mean retention times and seed‐dispersal distances. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Ducks are known to be important seed dispersers, but the role of geese in plant dispersal is less clear. Wintering populations of migratory geese are undergoing rapid changes in distribution and habitat use in response to climate change and changes in land use, and the implications for seed dispersal have not previously been studied. At the southern end of Eurasian goose flyways, numbers are declining through short‐stopping. The Doñana wetlands, or ‘marismas del Guadalquivir’, in south‐west Spain were formerly Europe's most important wintering grounds for the greylag goose Anser anser. There, we collected 151 faecal samples to compare seed dispersal by endozoochory in early and late winter in natural marshes and ricefields. We also tested seed germinability and simulated potential seed dispersal distances to assess the importance of this decreasing wintering population for dispersal of dry‐fruited plants previously assumed to rely on abiotic seed dispersal over short distances. We retrieved 1196 intact seeds belonging to 24 different taxa, including eight species not previously reported from waterfowl (Anatidae) vectors. Seeds were present in 47% of samples, with a peak of 90% in natural marshes in November, compared to only 27% in ricefields at the same time, or in the same marsh site in February. Seed abundance and richness per sample were significantly higher in early than late winter, and in natural compared to in artificial wetlands. Major differences in plant species composition between sampling sites were partly related to habitat differences and moisture requirements of individual species. Germinability in aquatic plants was higher when gut passage was followed by cold storage for 2 months prior to germination tests. We simulated seed dispersal events to and from our sampling sites using GPS tracking of three geese. This suggested that seeds can be dispersed up to 25 km during daily movements, with a median of 0.2–5 km, depending on the sampling site. The most frequent dispersal syndrome assigned to the plant species dispersed by geese was barochory (gravity), and geese disperse plants much farther than the mechanisms predicted by their syndromes. Geese likely have an important role in the dispersal and connectivity of plant populations within and beyond Mediterranean wetlands, providing an ecosystem service which is threatened by changes in migratory behaviour. Our results highlight the importance of studying seed dispersal interactions involving migratory waterbirds in the current context of species loss and distribution shifts, as many crucial interactions may be disappearing even before they are discovered. [ABSTRACT FROM AUTHOR]

Habitat selection of seed-dispersing animals influences where seeds are deposited, seedling establishment, and population dynamics. In the Patagonian temperate forests there is a key mutualistic relationship between the mistletoe Tristerixcorymbosus and its seed disperser, the nocturnal arboreal marsupial Dromiciopsgliroides. In this study, we analyzed the habitat selection of D.gliroides at two different habitat scales: site selection and step selection. Also, we analyzed if the selected microsites by this marsupial are suitable for the establishment of T.corymbosus. We captured 24 individuals in Parque Municipal Llao Llao (San Carlos de Bariloche, Argentina) during the austral summer of 2014 and 2015. The captured individuals were equipped with a spool and line device to register habitat use: substrate, vegetation cover, diameter and angle of branches. We used a conditional hierarchical logistic Bayesian regression at each habitat scale. We found that, at the site scale, D.gliroides selected habitats with more shrub cover and, at the step scale, D.gliroides selected more T.corymbosus host species. Besides, our results show that D.gliroides selected branches with intermediated size (4–10 cm) and also horizontal branches. The relationship between the selected sites and those where it deposits the T.corymbosus seeds suggests that the marsupial dispersing the seeds to suitable hosts and branch sizes. Therefore, the behavior of D.gliroides would be favoring the regeneration of T.corymbosus. [ABSTRACT FROM AUTHOR]

• Indigenous birds and mammals are consumers of Cotoneaster pannosus fruits. • Birds swallow fruits whole and excrete viable seeds. • Pulp removal enhances germination rate regardless of whether this is mechanical or through bird ingestion. • Germination rate and success were extremely low across three different treatments. Shrubs from the Rosaceae family have become emerging invasive alien plants in the montane grasslands of South Africa. The most common of these species include Cotoneaster pannosus and Pyracantha angustofolia. We explored the seed dispersal and germination of C. pannosus, a species notorious for forming monocultures that can outcompete native plants. This was achieved through the identification of seed dispersers using observations and remote cameras, and by exploring the germination success and rate of C. pannosus seeds ingested by frugivorous birds using laboratory feeding experiments. Footage and direct observations revealed birds and mammals consumed C. pannosus fruits. Field observations and feeding experiments showed that birds ate whole fruits, and the seeds passed through the gastrointestinal tract within 15 min. The germination success was <8 % for the treatments (whole fruits, manually de-pulped fruits, defecated seeds). Germination rates for seeds that birds defecated were faster (192 days) than manually depulped seeds and seeds buried as whole fruits, although differences between treatments were non-significant. Birds and mammals were confirmed as consumers of C. pannosus fruits and, therefore, seed dispersers, but unlike other invasive Rosaceae species, such as P. angustifolia , ingestion by birds is not as crucial for speeding up germination. However, pulp removal improved the rate of germination, regardless of whether this is achieved through bird ingestion or manual de-pulping. Birds are, therefore, one of the disperser taxa driving the spread of C. pannosus in the grassland biome; however, the low germination rate is slowing the spread of the invasion. [ABSTRACT FROM AUTHOR]

Natural populations of Saposhnikovia divaricata (Turcz. ex Ledeb.) Schischk. have recently been subjected to strong anthropogenic impact due to biologically active substances with a wide spectrum of action detected in plants. The purpose of this study is to determine the state of natural populations of S. divaricata and identify biological features of the species that contribute to the stability of the populations. Seven coenopopulations have been studied in the Republic of Buryatia. Phytocenoses and ontogenetic states of S. divaricata are described, demographic indicators of coenopopulations are given, and environmental and biological factors affecting the existence of this species have been identified. S. divaricata has a wide ecological amplitude and occurs from tree communities to steppes and fallow areas. Its proportion in communities does not exceed 2% of the general projective cover. Most populations are characterized by a low density of individuals (5–48 individuals/100 m2) due to the destruction of plants (root extraction). One stable population without damage (density of 209 individuals/100 m2) and one recovering population (113 individuals/100 m2) have been revealed. The height of generative plants varies significantly from 35 to 100 cm, depending on the growing conditions. Environmental factors that negatively affect the stability of natural populations of S. divaricata include biotic (massive damage to seeds by invertebrates) and anthropogenic (root harvesting and grazing) ones. A number of biological features determine the strategy of the species in nature: a probable low stock of seeds in soil and a sharp rise in the amount of seedlings during seed dispersal; biological longevity of seeds for more than 5 years; early contractility of roots; dormant buds and renewal buds in the leaf axils of previous years are protected by remnants of leaf sheaths; when the apical bud is damaged, monopodial growth is changed to sympodial (more often at the beginning of the virginal ontogenetic state); duration of the pregenerative period of 10–12 years; and monocarpicity, up to 50% of generative individuals in the population form false whorls, the percentage of fruit formation in a simple umbel is 50–100%. [ABSTRACT FROM AUTHOR]

Rapid urbanization has caused a series of environmental problems, but its influences on animal-related ecological functions (e.g., seed dispersal) have not been fully studied. Mammals are ideal models for studying the functional consequences of urbanization because they are sensitive to environmental changes. It is well known that large- and medium-sized mammals are vulnerable in fragmentation ecosystem. However, little is known about the functional responses of small mammals (e.g., rodents) to the rapid urbanization. Using infrared cameras and tagged seeds, here, we quantified mammals and mammal-mediated seed dispersal (i.e., Quercus variabilis) in 11 forest patches along city-suburb-exurban gradient in a rapidly urbanizing megacity, central China. We wanted to determine the effects of defaunation on seed dispersal in the isolated urban forests. The results showed that abundance of seed dispersers was higher in the natural exurban forests than in the city forests, while abundance of seed predators did not vary significantly along the city-suburb-exurban gradient. The percentage of seed dispersal was positively associated with the abundance seed dispersers, while the percentage of seed predation increased with the abundance of seed predators. Seed dispersers loss (e.g., small rodents) disrupted the mammal-mediated seed dispersal, possibly contributing to the degradation of urbanized forests. These results suggest that defaunation effects are obvious in the rapidly urbanizing cities, in that abundance of seed dispersers, and mammal-mediated seed dispersal are undergoing decline in the urbanized forests. In order to maintain seed dispersal and natural regeneration of urban forests, diversity of small mammals (e.g., rodents) and their ecological services should be considered in ecological-based urban planning and management. [ABSTRACT FROM AUTHOR]

Changes in canopy structures caused by harvesting and regeneration practices can significantly alter the wind environment. Therefore, it is essential to understand the wind patterns influenced by seed tree arrangements for predicting seed dispersal by winds and ensuring the success of natural regeneration. This study aimed to identify how wind speed responds to seed tree arrangement designs with differing horizontal distances, vertical positions, and free-stream wind speeds. A wind tunnel test was conducted using pine saplings for a scale model of various seed tree arrangements, and the change in wake speed was tracked. The wake's relative wind speed averaged 71%, ranging from 3.5% to 108.5%, depending on the seed tree arrangement, distance from saplings, and vertical position. It peaked within the patch of three seed trees compared to other arrangements and at the top canopy layer. The empirical function effectively described the wind speed reduction and recovery with distance from saplings. For instance, the minimum wind speed was reached at 0.6–2.2 times the canopy height, and a wind speed reduction of over 20% of the free-stream wind speed was maintained at a 1.6–7.6 canopy height. A negative relationship between the seed tree leaf area and the relative wind speed was observed only at the top canopy layer. This study presents empirical evidence on the patterns of wake winds induced by different types of heterogeneous canopy structures. [ABSTRACT FROM AUTHOR]

Research highlights: At the turn of the 21st century, there were more forest territories found disturbed by both natural processes (climate change, wildfires, insect outbreaks, permafrost thawing, etc.) and anthropogenic interferences (air pollution, clearcuts, etc.). Seed collecting, then growing seedlings in forest nurseries, and then planting seedlings over lost forest areas are the forestry measures needed to restore the forest after disturbances. Goals were to construct bioclimatic models of ranges and seed mass of major Siberian conifers (Siberian pine (Pinus sibirica Du Tour), Siberian fir (Abies sibirica Ledeb.), Siberian spruce (Picea obovata Ledeb.), Siberian larches (Larix sibirica Ledeb., L. gmelini (Rupr) Rupr, and L. cajanderi Mayr.) and Pinus sylvestris L.) and predict their potential change in a warming climate by the mid-century. Methods: Multi-year seed mass data were derived from the literature, seed station data, and were collected in the field. Climate data (January and July data and annual precipitation) were derived from published Russian reference books and websites on climate. Bioclimatic indices (growing degree-days > 5 C, negative degree-days < 0 C, and annual moisture index) were calculated from January and July temperatures and annual precipitation for both contemporary and the 2050s (2040–2060) climates using the general circulation model INM-CM5-0 and two climate change scenarios, ssp126 and ssp585, from CMIP6. Our bioclimatic range models (envelope and MaxEnt models) and regression seed mass models for major conifers were built based on these bioclimatic indices. Additionally, their ranges were limited by the permafrost border, which divided the forest area into the permafrost-free zone, where five conifers are able to grow, and the permafrost zone, where only one conifer, Dahurian larch, is able to survive. Results: Under warmed climates, the ranges of all Siberian conifers would expand 1.5-fold due to the decrease in the permafrost zone, except Dahurian larch, which would lose 5–20% of its coverage due to permafrost retreat. Conifers shifting northward would be slower than predicted only by warmed climates because permafrost would thaw slower than climates would warm. Scots pine may expand by up to 60%, covering dryer lands in the south. Future climates were found to favor seed mass increase for major Siberian conifers and for heavier seed to shift northward. Our major conifers differ by the type of seed dispersal mode: zoochoric, animal (Siberian pine) and anemochoric, and wind-dispersed (other five trees). The seed masses of the five anemochoric conifers varied within the range of 1.5–15 g of 1000 seeds, which is about 40–50-fold less than that of zoochoric Siberian pine. Site climate explained about 28–65% of the seed mass variation for the five anemochoric trees and only 11% for Siberian pine (zoochoric tree). This finding needs additional research to explain the reasons. Conclusions: Warmed climates would favor the expansion of the ranges of major Siberian conifers and their seed mass to be heavier, which would support the high-quality seed production for forest well-being and its restoration in Siberia. [ABSTRACT FROM AUTHOR]

Background: Spatial clumping of plants results in intense competition. Aims: We analysed the extent of clumping of Proteaceae seedlings across the Cape Floristic Region after fire. Methods: To demonstrate the extent of clumping in 23 species, we analysed the seedling and adult densities in 290 post-fire surveys each of 100 × 1 m2 plots using standard indices of clumping. Key results: We detected clumping of Cape Proteaceae seedlings, whereas parent plants were less clumped. The clumping is not due to limited safe sites for seedlings because the number of plots at a site with at least one seedling was positively related to the number of seedlings at the site. Sites with seedlings were enriched in nutrients relative to those without. Conclusions: The possible benefits of clumping are saturation of granivores and co-location of buried seeds with nutrient-rich patches of fire-derived ash and debris. A cause of clumping is seeds sticking together. Clumping, which is strongly intraspecific, has implications for trait evolution and the dominance of reseeders over resprouters. Strong clumping reduces the usefulness of the widely used seedling:parent index to determine whether fires were favourable or not. Implications: Clumping has implications for understanding seed dispersal distances, seedling versus adult traits, fire responses and demography. Seedlings of Cape Proteaceae tend to occur in clumps and these clumps thin out with time to produce adult stands that are less clumped. We analysed seedling and adult densities and discuss the implications for trait evolution and dominance of reseeders over resprouters of strongly intra-specific clumping. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between seed morphological traits and dimensions to adapt to arid environments, focusing on microlevel seed structures. Utilizing advanced imaging techniques, we visualized complex seed features and explored their role in enhancing plant adaptability to dry climates, shedding light on crucial mechanisms underlying seed germination and survival strategies in water‐limited ecosystems. Seed morphotypes refer to the physical attributes of seeds, such as size, shape, color, texture, and structure. Fifteen species belonging to ten plant families were examined to investigate seed micromorphological features. Each species exhibits unique seed traits adapted for survival in harsh conditions. Features such as seed size, shape, texture, and surface ornamentation varied significantly among species, reflecting adaptations to optimize seed dispersal, germination, and resilience to arid climates. Seed shape, color, and texture were observed under scanning electron and stereomicroscopes. Micromorphological ultrastructural information has proven useful in determining plant evolution, classification, and ecology. Seed shape varied from elliptic, oblong, ovate, pyramidal to spherical. Surface stratification varied from rugulate, striate reticulate, foveolate, granular to rugose. The seed size varied among species, from very small in Cleome arabica (L = 1.4 mm and W = 0.7 mm) to very large in Aerva (L = 5.1 mm and W = 2.6 mm). Seed color varied from brown, dark brown to black. The microstructural seed traits in arid environments provide valuable insights into plant adaptations to dry climates and have significant implications for crop breeding programs and ecological restoration efforts. [ABSTRACT FROM AUTHOR]

Rodents are important seed dispersers of plants because they move seeds far away from the parent trees and hoard seeds in the soil, benefiting seed dispersal and regeneration. Traits of plant seeds and animals are associated with rodent‐mediated seed dispersal, but animal personality, the consistent individual behavioral differences in time and environments, has not been fully considered. Here, we first measured the personality of 26 Niviventer confucianus in the laboratory, and 10 individuals in the field of one population, and then tested their behavior of seed consumption and hoarding both in semi‐natural enclosures and the field. We tested the hypothesis that individuals with different personalities have different preferences for seed consumption and hoarding, which has different implications for seed dispersal and regeneration. Under the enclosure conditions, all parameters of personality are repeatable; bold individuals harvested fewer seeds but scatter‐hoarded more seeds and dispersed farther than timid ones, whereas active individuals consumed more seeds, but left fewer seeds on the ground surface than inactive ones. In the field, boldness, activity, and exploration of the animals are repeatable; bold individuals scatter‐hoarded more seeds to farther distances than timid ones, whereas active individuals harvested and consumed more seeds than inactive ones. These results suggest that bold rats tended to scatter hoard seeds and disperse them to a longer distance, implying they are more effective in seed dispersal. In the future, animal personality (e.g. boldness and activity) should be considered in seed dispersal studies and ecological‐based manipulation in seed dispersal and regeneration of forests. [ABSTRACT FROM AUTHOR]

Zoysia japonica, a low growing grass, is tolerant to grazing and trampling. Kinkazan Island in northern Japan is inhabited by sika deer (Cervus nippon). The deer population increased in the 1970s at a shrine garden in the western part of the island, leading to expansion of Zoysia swards around the shrine garden and their colonization of remote open patches. The expansion around the garden is due to elongation of the rhizome, but expansion to remote places may be due to endozoochory by deer. This appears to be a good example of the “foliage is the fruit” hypothesis (the FF hypothesis) proposed by Janzen (1984; American Naturalist 123:338–353). To demonstrate this, we confirmed the expansion of the Zoysia swards and tested the traits of Zoysia by field surveys and indoor experiments. The Zoysia peduncles stood among the leaves, and sika deer fed on both the seeds and leaves. One deer fecal pellet contained about 20 seeds at its peak in June. In the feeding experiment, the survival rate through digestion was 38%. In the greenhouse experiment, the germination rate was 72%. An outdoor experiment showed that germination rates of the ingested seeds were 5% in a dark habitat and 58% in a bright habitat. Zoysia exhibited many of the traits presented by the FF hypothesis, and sika deer functioned as seed dispersal agents. Therefore, the Zoysia—sika deer relationship seems to support the FF hypothesis. [ABSTRACT FROM AUTHOR]

Seed dispersal distance is an important indicator of how well a plant species can cope with environmental changes. Seeds of wetland plants are primarily dispersed by hydrochory (floating on the water surface) or endozoochory (ingestion and egestion by animals). However, both mechanisms can also be combined (diplochory), which increases dispersal distances. In wetlands, seeds often float on the water surface before ingestion and transport by animals, such as waterbirds. Here, we consider what happens next after endozoochory and test whether seeds dispersed inside waterbirds can then continue to disperse by hydrochory. We experimentally assessed the buoyancy capacity of 41 wetland plant species for 14 weeks before and after simulated passage through avian digestive systems. This revealed that (1) seeds of plants previously assigned a hydrochory dispersal syndrome floated longer than those from other syndromes, but with considerable overlap; (2) fully aquatic and shoreline plant species had seeds with stronger buoyancy than terrestrial plants; and (3) digestive processes negatively affected seed buoyancy capacity for all plant species, which included wetland species with a typical hydrochory syndrome. The capacity for hydrochory is more limited after endozoochory than beforehand, with strong implications for the effectiveness of seed dispersal. [ABSTRACT FROM AUTHOR]

Most of the plants using epizoochory show adaptations to this diaspore dispersal strategy by having the diaspores covered by barbs, hooks, spines or viscid outgrowths, which allow diaspores to easily attach to an animal surface. Many previous studies have been mainly focused on the dispersal distances and efficiency, or effectiveness of diverse attachment structures depending on their size, anatomy, and morphology. However, the knowledge about the mechanical properties of these structures remains rather poor. In this study, we use a combination of scanning electron microscopy, energy dispersive X-ray element analysis and nanoindentation, to examine the microstructure, biomineralization and mechanical properties of single hooks in Arctium minus, Cynoglossum officinale and Galium aparine. Both the biomineralization and mechanical properties of the hooks strongly differ in examined plant species; mechanical properties depend on the biomineralization pattern, such as the accumulation of silicon and calcium. Elastic modulus and hardness decrease in the series C. officinale G. aparine A. minus. Anisotropic mechanical properties are found between the radial and longitudinal directions in each single hook. By characterizing the mechanical properties and biomineralization of plant hooks, this paper contributes to the understanding of attachment biomechanics related to seed dispersal. The dispersal of seeds is essential for plant survival. Many of the plants that use the outside surface of animals to transport the seeds show adaptations to this dispersal strategy by having the seeds covered with hooks. Although these hooks have various sizes, morphologies and anatomical structures, all of them provide mechanical interlocking to animal surfaces. To reduce the risk of interlocking failure, the hooks are usually reinforced by mineralization. However, the relationship between mineralization, mechanical properties and specialized function of plant hooks has been largely overlooked. Here we perform a characterization study on the hooks of three plant species. Our results deepen the current understanding of the mineralization-material-function relationship in specialized hooks of plant seeds. [Display omitted] [ABSTRACT FROM AUTHOR]