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• Outcomes of interactions can be sorted along continua from mutualism to antagonism. • We modelled seed dispersal and predation effects by hawfinches on a tree population. • At rates above 72% seed predation, its costs exceeded benefits of seed dispersal. • Changes in environment, seed dispersal and plant demography influence the continuum. • As the hawfinch predated at least 80% of seeds, it is an exploiter of the mutualism. Seeds removed by animals have one of two mutually exclusive fates – they are either predated or dispersed and still alive. The quality of seed dispersal by animals and the number of predated seeds will therefore determine net interaction outcomes for plants. Yet, it is poorly understood what proportion of removed seeds animals can predate before benefits of dispersal no longer outweigh costs of seed loss. Here, we calculated the mutualism-antagonism continuum for seed removal of the fleshy-fruited tree Frangula alnus by the seed-predating bird Coccothraustes coccothraustes in Białowieża Forest. We integrated effects of the bird during seed dispersal (fruit handling, seed predation, and seed deposition) into microhabitat-structured tree population models. Results of our models showed that the probability of a seed of F. alnus reaching maturity after seed removal by C. coccothraustes decreased from 0.0028% to 0% as seed predation increased from 0% to 100%. Seed removal was beneficial when less than 63.7% of seeds were predated, and antagonistic when more than 72.0% of seeds were predated. Modifying key model parameters (here, the negative effect of fruit pulp on seedling recruitment and the frequency of forest gaps) decreased and increased rates of seed predation, at which costs of seed loss outweighed benefits of seed dispersal (from 37.9% to 80.7%). Our findings highlight that benefits of animal seed dispersal can largely outweigh costs of seed predation in a fleshy-fruited tree. Yet, the mutualism-antagonism continuum of seed removal depends on intrinsic factors (e.g. variation in interactions among individuals) and extrinsic factors (e.g. the environment) of seed dispersal and plant demography. Because C. coccothraustes was observed predating at least 80% of removed seeds, it appears to be an antagonist of animal-dispersed plants and exploiter of the seed dispersal mutualism. [ABSTRACT FROM AUTHOR]

• Low-intensity selective logging has no significant effect on seed predation. • High-intensity selective logging reduces tree seedling density. • High-intensity selective logging increases root sucker density. • Low-intensity selective logging has no significant effect on soil nutrient status. Woodlands that have been affected by selective logging are ubiquitous in southern Africa but how this harvesting practice impacts seed regeneration of dominant tree species remains unclear. To address this deficiency, the study assessed the effects of different selective logging intensities on post-dispersal seed predation and seedling recruitment of Brachystegia spiciformis Benth. in Ruzawi Forest, Zimbabwe. Data were collected in blocks that were subjected to selective logging intensities of 0 % (00 L, unlogged), 5 % (05 L), 10 % (10 L), and 15 % (15 L). Ten years after logging, three transects (200×30 m) were laid in each block and five main plots (20×20 m) were laid in each transect, making a total of 60 plots. Low-intensity selective logging of 5 % did not cause any significant changes to seed predation levels, densities of true seedlings, seedling sprouts and root suckers, and soil nutrient concentrations. Seed predation was significantly greater in 10 L and 15 L sites than in unlogged and 05 L sites. As logging intensity increased, the relative importance of sexual reproduction decreased and that of vegetative reproduction increased. Canopy cover and seedling density decreased as logging intensity increased but a reverse trend was observed with grass biomass and root sucker density. Grass biomass was negatively correlated with the density of true seedlings and seedling sprouts. Soil organic C, N, P, and K were all significantly reduced in 10 L and 15 L sites than in unlogged and 5 L sites. Our results suggest that unless selective logging is practiced at very low harvest intensities, it can create opportunities for the growth of dense grass swards, potentially promoting rodent seed predation and limiting seedling recruitment. This study recommends effective use of low-impact selective logging practices as well the adoption of woodland management policies that prioritize sustainable utilization practices. [ABSTRACT FROM AUTHOR]

Crop production with little to no tillage, permanent plant or residue soil cover, and diverse crop rotations are frequently marketed throughout the world as a way to sustainably produce crops. While these management techniques contribute a wide suite of ecosystems services to crop production systems, they typically come at the expense of increased reliance on herbicides for weed control, which is known to negatively impact ecosystems. This two-year study investigated three cropping systems (i.e., integrated, organic transition and no-till) to determine their effects on granivorous invertebrate activity-density, invertebrate weed seed predation and crop yield. A redundancy analysis (RDA) revealed significant effects of cropping system on invertebrate community structure and associated seed predation rates. Specifically, species abundance and seed predation rates in the integrated treatment differed from those found in the organic and no-till systems (F = 6.97, p = 0.002). Secondarily, no-till systems differed from organic systems (F = 3.09, p = 0.006). The analysis indicated that most invertebrate groups, and seed predation rates for all weed species assessed, were more highly associated with the integrated system. Crop yields did not differ significantly between cropping systems (One-way ANOVAs, p >0.05). This work shows that the application of an integrated crop management system results in an increase in beneficial invertebrate activity-densities and increases surface seed predation when compared to no-till and organic systems. These results suggest that integrated cropping systems can reduce herbicide application while effectively controlling weeds and thereby help to reduce the ecosystem impact of agricultural systems. [ABSTRACT FROM AUTHOR]

Habitat conversion to agricultural land is one of the main threats to terrestrial biodiversity and can affect ecosystem processes and cause changes in ecosystem services (ESs) and disservices (EDs). Yet, studies often rely only on the abundance and diversity of the service providers; the effects on ecological processes of habitat conversion are rarely directly monitored. In this study, we used the sentinel approach to evaluate how habitat conversion from native forest to agricultural land affected ESs and EDs on an oceanic island. We quantified herbivory on lettuce plants, invertebrate and vertebrate predation rates on artificial caterpillars, pollination on strawberry plants, seed predation on wheat and mustard seeds, and leaf decomposition rates in native forests, maize fields and pastures on Terceira Island, Azores (Portugal). Herbivory, invertebrate predation rates, and pollination service were not significantly different between habitats. Vertebrate predation rates in native forests (mean 6.1% d−1) were significantly higher than that in pastures (0.3% d−1), or high-elevation maize fields (0.5% d−1), and marginally higher than in low-elevation maize fields (2.2% d−1). Overall seed predation after 48 h was significantly higher on wheat (mean 16.8%) than mustard seeds (5.6%). High-elevation maize fields also had higher seed predation (27.8%) than low-elevation ones (0.6%) or pastures (3.6%), but did not differ from the native forest (12.9%). Decomposition after 90 days was highest in pastures (78.4% and 45.9%, for tea and rooibos, respectively); although no significant differences between habitats were detected, except for low-elevation maize fields (64.4% and 33.6%). Conversion from native forest to cultivated land did not cause a clear decrease in the intensity of the studied ESs/EDs except for vertebrate predation. Using direct monitoring tools to simultaneously and consistently quantify multiple ecological processes is not only possible but needed, as ecological processes can respond differently to landscape changes. [Display omitted] • Ecological processes were assessed after converting Azorean forests to agriculture. • All quantified ecosystem services/disservices showed idiosyncratic changes. • Predation rates significantly decreased when forest was converted to cropland. • Herbivory and pollination did not indicate significant changes. • Decomposition and seed predation increased in high elevation maize fields and pastures. [ABSTRACT FROM AUTHOR]

Forest fragmentation often leads to changes in the abundance and composition of various organisms, thereby affecting biotic interactions. Currently, many studies lack consensus on the magnitude or direction of the impact of forest fragmentation on plant-animal interactions. Here, we employed seed-rodent interaction as a case study and assessed the removal by rodents of 66,960 seeds belonging to 31 woody species in 18 fragmented forests with areas of 1.05–14,517.63 ha, in a seriously fragmented tropical area in Southwest China for two consecutive years. Our study provided strong evidence that forest fragmentation affected seed-rodent interactions but did not follow a consistent pattern between years. Forest size and edge effects on seed removal were mainly due to variations in seed availability but not rodent activity. Interestingly, the effect of fragment size on seed removal was species-specific with monotonic decreases as well as U-shaped and humped-shaped patterns. These remarkable spatiotemporal and interspecific variations pertaining to forest fragmentation impact on seed removal may translate into subsequent seed germination and seedling regeneration processes, which may further influence the species composition in different fragmented forests. This complexity in responses among plant species reiterates the need to consider the interspecies specificity in conservation and management initiatives of fragmented forests. Additionally, we recommend that multiple field surveys involving multiple species be conducted in future studies focusing on forest fragmentation to help us better understand fragmentation effects on ecological processes. • Fragmentation influences seed-rodent interactions inconsistently. • Interannual and interspecific variations were observed. • Seed availability can explain interannual variations of seed removal. • Long-term studies are crucial for these ecological insights on effects of fragmentation. [ABSTRACT FROM AUTHOR]

Insect herbivores can inflict substantial costs on plant reproductive success. Seed herbivory impacts directly by reducing the number of seeds and therefore the dispersal and reproductive potential of the plant. Fig trees, Ficus , provide keystone resources for tropical forests. The pollinating fig wasps develop inside figs, so consumption of unripe figs results in trees not only losing seeds but also their pollen dispersers. Selection to defend figs should therefore be strong. Seed herbivory is understudied in tropical forests and most data has been collected from fallen fruits. Here we use canopy sampling to identify fig-consuming larvae in central Panama and quantify both their consequences for the fig trees' reproductive success and the defensive value that ants provide against these larvae. Field surveys of 46 crops from nine fig species revealed that larvae could destroy up to 80% of figs on a tree. From seven Ficus species we barcoded (using COI) 51 individual fig consuming larvae (mainly Lepidoptera) that grouped into seven molecular operational taxonomic units. Lepidopteran larvae formed two feeding strategies, either stationary within a fig or tunneling between figs. Within the context of our study, stationary larvae were specialists whereas tunneling larvae were either specialists or generalists found on different Ficus species. Trees with ants had significantly fewer figs consumed by larvae (9% ± 17% (mean ± SD) for trees with azteca ants and 16% ± 24% for trees with other ants) than did trees without ants (51% ± 27%). Our results corroborate earlier findings that hosting ants can be an effective defensive mechanism for trees against seed herbivores or other antagonistic insects. Our study contributes to a wider body of research around the networks of insects associated with figs that highlights the importance of a multitrophic approach for understanding mutualism stability and persistence in the face of antagonism. • Seed herbivory impacts plant fitness, yet it is understudied in tropical forests. • We studied six lepidopteran seed predators across eight Panamanian Ficus species. • Lepidopteran larvae can destroy up to 80% of the figs on an individual tree. • We found two feeding strategies: stationary specialist and tunneling generalists. • Trees with ants had significantly fewer figs consumed by larvae than trees without. [ABSTRACT FROM AUTHOR]

• Serotinous leucadendron produce light and dark polymorphic, sometimes mottled seeds. • These seeds background match post-fire soil backgrounds. • Small mammal granivores consumed background matching seeds indiscriminately. • Visual models suggest the background matching seeds are cryptic to bird granivores. • The role of visually-cued granivores is likely underestimated in fynbos. Plant species with large seeds are susceptible to high levels of seed predation. Seeds of serotinous Proteaceae plants display what appears to be background matching, with polymorphic colours or ornamented surfaces reducing their detectability on certain soil types. We investigated whether seed crypsis (background matching) in Proteaceae seeds can reduce seed predation by visually-cued bird granivores using field observations, seed removal trials and spectrophotometry data. We found no difference in seed predation of winged seeds on different substrates by a diurnal rodent granivore. We therefore ruled out rodent granivores as selective agents driving visual seed crypsis in Cape Proteaceae. Light seeds of most polymorphic Leucadendron seeds showed background matching with their native soils, with granivorous birds predicted to have difficulty distinguishing them apart. Monomorphic Protea seeds with hairs generally do not background match with no reduction in detectability from visually cued predators. This is the first widescale documentation of seed colours and first description of crypsis in the seeds of Cape plants. We suggest that seed colour polymorphisms are adaptations to substrate-specific seed predation biases, with visually-cued bird granivores the likely selective agent driving the visual crypsis of Cape fynbos seeds. [ABSTRACT FROM AUTHOR]

Woody encroachment in savannas represents an ecological process of current global interest given its negative impact on ecosystem functioning, particularly on forage production. Traditional savanna models propose competition and niche differentiation as the main mechanisms allowing tree-grass coexistence. Demographic models, instead, propose abiotic and biotic factors as bottlenecks controlling vital rates and transitions from seeds to adult trees. The role played by domestic grazing on woody encroachment is yet controversial. Here, using a multistage tree life approach, we combine both models and evaluate the role of grazing and herbaceous vegetation on woody recruitment in a Neotropical savanna dominated by Vachellia caven , a successful and widely spread encroacher tree species. We performed three experiments to evaluate seed predation, seedling emergence and survival of V. caven by manipulating cattle grazing (grazed and ungrazed areas) and herbaceous vegetation presence (vegetated and unvegetated). Finally, we combined the results of the three experiments to estimate the probability of plant recruitment across these experimental factors. Grazing decreased seed predation by half, did not modify seedling emergence and decreased seedling survival. Herbaceous vegetation did not affect seed predation nor seedling emergence rate, but increased seedling survival. Overall, the net effect of grazing on V. caven recruitment was neutral since the increase in seed availability due to the reduction in seed predation rate was compensated by the negative effect of grazing on seedling survival. Our analysis revealed that cattle grazing and herbaceous vegetation had contrasting effects on the seed and seedling life stages. We propose that in order to restrain the early stages of encroachment, cattle grazing pressure could be managed following the seasonality of demographic tree transitions. Through rotational grazing amongst paddocks, stocking rates could be relaxed during the primary dispersal stage to maximize granivory, and then increased to enhance the chance of seedling consumption and trampling. [Display omitted] • Woody encroachment drivers change whit the encroacher's life stage. • Cattle increased seed availability by a negative effect on seed predation rate. • Cattle decreased seedling survival through consumption and trampling. • Woody encroachment could be limited through rotational grazing amongst paddocks. [ABSTRACT FROM AUTHOR]

To expand our understanding of what tasks are particularly helped by UV vision and may justify the costs of focusing high-energy light onto the retina, we used an avian-vision multispectral camera to image diverse vegetated habitats in search of UV contrasts that differ markedly from visible-light contrasts. One UV contrast that stood out as very different from visible-light contrasts was that of nutrient-dense non-signaling plant foods (such as young leaves and immature fruits) against their natural backgrounds. From our images, we calculated color contrasts between 62+ species of such foods and mature foliage for the two predominant color vision systems of birds, UVS and VS. We also computationally generated images of what a generalized tetrachromat, unfiltered by oil droplets, would see, by developing a new methodology that uses constrained linear least squares to solve for optimal weighted combinations of avian camera filters to mimic new spectral sensitivities. In all visual systems, we found that nutrient-dense non-signaling plant foods presented a lower, often negative figure-ground contrast in the UV channels, and a higher, often positive figure-ground contrast in the visible channels. Although a zero contrast may sound unhelpful, it can actually enhance color contrast when compared in a color opponent system to other channels with nonzero contrasts. Here, low or negative UV contrasts markedly enhanced color contrasts. We propose that plants may struggle to evolve better UV crypsis since UV reflectance from vegetation is largely specular and thus highly dependent on object orientation, shape, and texture. [ABSTRACT FROM AUTHOR]

Agricultural intensification is a major driver of biodiversity loss, but the majority of studies highlighting these threats come from industrialised agriculture in temperate countries of the global North. However, more than 30% of global food production is produced by smallholder farmers, particularly in Africa. We know very little about the impact of these farming practices on arthropod communities and associated ecosystems in dryland agroecosystems. We investigated the trophic group composition of arthropod communities (detritivorous, herbivorous, predatory & mixed feeders) and levels of associated ecosystem functions in replicated maize fields, paired adjacent natural bushveld habitats and the edge habitats between them in north-eastern Namibia and central-eastern Botswana during the dry and wet seasons. Predator activity densities differed significantly between habitats depending on the season, with higher numbers in natural habitats in the wet season but lower numbers in the dry season compared to maize fields. In general, edge habitats had higher numbers of predators than the other habitats. Predator attack rates on artificial caterpillars in both seasons and dung removal in the wet season were higher in habitats with natural vegetation (natural and edge). However, dung removal in the dry season and herbivory in the wet season were highest in the maize fields, the latter due to high level of fall armyworm infestation. Wet season multifunctionality was higher in natural habitats in Botswana, and to a lesser extent in Namibia, than in maize fields. Smallholder agriculture is not detrimental to decomposers, herbivores and mixed feeders compared to adjacent natural habitats, but may be detrimental to the provision of some ecosystem services. These results highlight the challenge of sustainably managing dryland agricultural land that is marginal for crop production, while providing smallholders with an optimal environment to benefit from the ecosystem services associated with arthropod communities. New conservation agriculture practices need to support the production of higher and more stable yields over time, while maintaining the limited impact of smallholder agriculture on biotic communities. • Dryland agriculture does not reduce trophic groups compared to natural habitats. • Predator attacks & dung removal (wet season) were higher in natural habitats. • Dung removal (dry season) & herbivory (wet season) were higher in maize fields. • Wet season multifunctionality was highest in natural habitats. • Smallholder agriculture reduced multifunctionality, but not arthropod numbers. [ABSTRACT FROM AUTHOR]

The lack of natural oak regeneration within forests is one of the most pressing conservation issues facing oak-dominated ecosystems in eastern North America. Although the restoration of suitable fire regimes appears to favor oaks over fire-sensitive mesophytes in many cases, differences in the effects of fire restoration on different species of oak have not received nearly as much attention. In particular, greater sapling recruitment of historically lowland Quercus alba compared to that of the historically upland and dominant Quercus stellata in response to fire restoration appears to be related to differences in seedling establishment, but the causes of these differences are not clear. In this study, we investigated species differences in acorn viability and rate of removal by predators, as well as differences in oak seedling emergence, survival, and vigor over two growing seasons (fall 2020 to fall 2022) in a restored oak woodland in northern Mississippi (USA). The proportion of viable acorns was greater for Q. alba than for Q. stellata, especially in 2020. Both species had similar acorn predation/removal rates in the winter of 2021. Seedling survival and vigor were greater in Q. alba than in Q. stellata , although these differences were more pronounced in patches dominated by the invasive Microstegium vimineum. Seedling emergence, survival, and vigor for both oak species were significantly lower in patches dominated by M. vimineum than in those dominated by native species. Neighboring vegetation and litter removal significantly increased seedling survival in both species. The positive effect of neighbor/litter removal on seedling survival was no greater in patches dominated by M. vimineum than in those dominated by native species, a result consistent with the existence of legacy effects of M. vimineum. Altogether, our findings suggest greater acorn viability combined with higher seedling survival and vigor in Q. alba than in Q. stellata may contribute to the lower regeneration rates of the historically dominant Q. stellata compared to encroaching Q. alba in fire-maintained woodlands. Negative effects of an invasive grass, M. vimineum , may further complicate restoration efforts. • Acorn and seedling viability can be limiting factors in natural oak regeneration. • Quercus alba had higher acorn and seedling viability than Quercus stellata. • Q. alba seedling survival was greater than that of Q. stellata in invasive patches. • Acorn/seedling viability and invasive species need consideration in oak restoration. [ABSTRACT FROM AUTHOR]

• We show novel mechanisms of seed to seedling survival in Hyaenanche globosa. • We show a first case of scatter-hoarding in recalcitrant Picrodendraceae seeds. • H. globosa seeds appear to deter a widespread seed predator Micaelamys namaquensis. • We suggest this is due to directed deterrence linked to H. globosa 's toxic seeds. • We show H. globosa seeds produce copious mucilage which aids germination. We investigated seed dispersal, directed deterrence and germination in the Cape narrow-endemic plant Hyaenanche globosa (gifboom). We found that gifboom seeds were predominantly removed and cached by the known scatter-hoarding specialist, small mammal, Acomys subspinosus , a first case of scatter-hoarding in the Picrodendraceae and the first case of a recalcitrant seed being scatter-hoarded in Cape fynbos. This represents an unusual exception to most hard-seeded, dormant scatter-hoarded seeds. In contrast, the ubiquitous, generalist, small mammal Micaelamys namaquensis , which is known to consume a variety of seeds, ignored gifboom seeds. The seeds, which contain the toxins, appear to have a directed deterrence effect on this common seed predator. We show that imbibed gifboom seeds produce copious mucilage, due to pectins, which aid in germination. Gifboom seeds appear to have two novel mechanisms for increasing seed to seedling survival, including toxins for seed predator deterrence and mucilage production for enhanced germination. [ABSTRACT FROM AUTHOR]

Prescribed burnings have been generally used for fuel reduction in Mediterranean forest ecosystems and in fire-prone areas. It is usually held that prescribed fire may alter microsite conditions, but very little is known about the impact of prescribed burning on Mediterranean pine species’ natural regeneration. In this study, we aim to know the effect of prescribed burning, soil preparation (scalping) and seed protection on the initial recruitment of Spanish black pine ( Pinus nigra Arn. ssp s alzmannii) , maritime pine ( Pinus pinaster Ait.) and Aleppo pine ( Pinus halepensis M.) in the Cuenca Mountains (central-eastern Spain) after a 1 year of experiments. Our results indicated that the seed emergence rate was higher in the scalped plots for Maritime pine and Aleppo pine. In the case of Spanish black pine, differences comparing treatments for the emergence rate were weaker. Scalped and protected plots showed the highest seedling survival rate for Aleppo pine and Spanish black pine whereas protected and control plots perform better in the case of Maritime pine. Thus, seed protection is a crucial factor for ensuring seedling survival after the first growing season. By considering our results about early pine species recruitment, prescribed burning must be carefully planned when the natural regeneration of Spanish black pine, maritime pine and Aleppo pine is the aim. [ABSTRACT FROM AUTHOR]

Since the early 2000s, there has been a resurgence in shade coffee production on the island of Puerto Rico. The newly restored specialized shade canopy consists of four native tree species, three of which are nitrogen fixers, and is intended to provide 30% shade cover once the trees are matured. Though much is known about the benefits of rustic and traditional shade plantations to coffee production, there is little information available for specialized shade plantations. Here, we investigate the ways in which fruit set, seed predation, bean weight, proportion of peaberries (i.e., malformed fruits), and beverage quality differ between sun and specialized shade plantations of Coffea arabica and Coffea canephora . Additionally, to assess whether coffee plants were pollen limited, we conducted a pollen supplementation experiment in which we compared pollen deposition and berry production on hand-pollinated branches to those of naturally, open-pollinated ones. We found that there was no evidence of pollen limitation on fruit set between sun and specialized shade plantations of C. arabica or C. canephora . We found that specialized shade benefits the proportion of C. arabica fruit set, without compromising bean weight or the proportion of peaberries produced. In comparison, C. canephora showed no improvement in the proportion of fruits set with specialized shade; however, beans from open-pollinated flowers weighed more in specialized shade than sun. Beverage quality was marginally better under shade, and for hand-pollinated flowers. Our results add to the limited body of work investigating the benefits of specialized shade coffee plantations on ecosystem services. [ABSTRACT FROM AUTHOR]

In brood pollination mutualisms, predation of developing fruit can have large negative repercussions for both plant and pollinator population dynamics. The Sonoran Desert rock fig Ficus petiolaris and its highly-coevolved wasp pollinator are subject to frequent attack by lepidopteran larvae that consume fig fruit and the developing seeds and larval pollinators they contain. We used generalized linear mixed models to investigate how the phenology, quantity, and spatial distribution of fig fruits is associated with variation in lepidopteran damage intensity on individual trees at nine geographic locations spanning a 741 km latitudinal transect along Mexico's Baja California Peninsula. We found lepidopteran damage to be strongly positively associated with more synchronous fig crops and larger trees, and only weakly associated with lower local host tree density. These results imply that fruit production that is asynchronous within trees and spread out over time, as observed in several fig species, benefits female and male components of fitness (pollen disperser and seed production, respectively) by reducing pre-dispersal predation by frugivores. [ABSTRACT FROM AUTHOR]

Taking advantage of facilitation mechanisms to counteract harsh environmental conditions may prove to be a successful strategy in the restoration of degraded man-made ecosystems. Seed sowing is often a viable and less expensive technique to restore forest cover in environments subjected to heavy anthropic disturbance. In this context, nurse plants and shield objects can improve microsite conditions, enhancing the emergence and growth of seedlings. However, their presence can also create preferred microhabitats for seed predators, and as a result, may alter their movement decisions and foraging behavior. In this study, we investigated whether nurse shrubs and artificial shade structures, with and without previous soil amelioration, could facilitate acorn emergence. We also tested their effects on the predation of acorns by small mammals, within the framework of a larger project aimed at restoring a Quercus robur L. forest. The research was conducted in a former roadbuilder’s yard located along the Mediterranean Corridor, in Northern Italy. The yard had been in use during the widening of a highway that runs parallel to a stretch of the Corridor. The area was restored in 2014. Mechanical preparation of the soil included two treatments, with and without the addition of compost and zeolitite. Acorns were then sown in plots in different microsites, i.e., (1) close to a shrub ( Cytisus scoparius L., Scotch broom), (2) to the north and (3) south of a shield object (a 30 cm × 30 cm wood particle board), and (4) without any protection element (control). We recorded acorn emergence and predation during the first growing season. At the end of the season, overall acorn emergence was observed to be low, and, surprisingly, was higher in the non-amended soil treatment. The amended soil had a higher temperature and a lower water volumetric content in the summer (JJA). No evidence of direct facilitation on emergence by shield objects or Scotch broom was found, but indirect effects were detected. Acorn predation was generally high (67.45%), but was negatively affected by the presence of C. scoparius . The distance of the plot from the rainwater drainage ditch surrounding the study site also influenced winter predation; a larger number of acorns were removed by rodents at longer distances from the drainage ditch. In order to restore degraded sites to lowland oak forests through direct seeding, it is necessary to deal with complex interactions between direct and indirect facilitation mechanisms, competition and predation. Predation was particularly important because of the high predation pressure on acorns. [ABSTRACT FROM AUTHOR]

Biodiversity-ecosystem function experiments test how species diversity influences fundamental ecosystem processes. Historically, arthropod driven functions, such as herbivory and pest-control, have been thought to be influenced by direct and indirect associations among species. Although a number of studies have evaluated how plant diversity affects arthropod communities and arthropod-mediated ecosystem processes, it remains unclear whether diversity effects on arthropods are sufficiently consistent over time such that observed responses can be adequately predicted by classical hypotheses based on associational effects. By combining existing results from a long-term grassland biodiversity experiment (Jena Experiment) with new analyses, we evaluate the consistency of consumer responses within and across taxonomic, trophic, and trait-based (i.e. vertical stratification) groupings, and we consider which changes in arthropod community composition are associated with changes in consumer-mediated ecosystem functions. Overall, higher plant species richness supported more diverse and complex arthropod communities and this pattern was consistent across multiple years. Vegetation-associated arthropods responded more strongly to changes in plant species richness than ground-dwelling arthropods. Additionally, increases in plant species richness were associated with shifts in the species-abundance distributions for many, but not all taxa. For example, highly specialized consumers showed a decrease in dominance and an increase in the number of rare species with increasing plant species richness. Most ecosystem processes investigated responded to increases in plant species richness in the same way as the trophic group mediating the process, e.g. both herbivory and herbivore diversity increase with increasing plant species richness. In the Jena Experiment and other studies, inconsistencies between predictions based on classic hypotheses of associational effects and observed relationships between plant species richness and arthropod diversity likely reflect the influence of multi-trophic community dynamics and species functional trait distributions. Future research should focus on testing a broader array of mechanisms to unravel the biological processes underlying the biodiversity-ecosystem functioning relationships. [ABSTRACT FROM AUTHOR]

Small semi-natural and natural habitats in agricultural landscapes are important for biodiversity. With modern and more intensive agricultural practices they have become smaller (less than 1600 m 2 ) and more isolated study which also affects ecosystem functions. Most ecosystem function studies using field experiments focus on a single function. Here, we investigate three functions in the same landscape at the same time. We investigated how local (trees, shrubs and grass-cover in small remnant habitats) and landscape factors (amount of and distance from key habitats i.e. forest and semi-natural grasslands) affect pollination, biological pest control and seed predation. We applied a multifunctional approach using different organisms to analyze pollination success ( Primula veris ), predation on aphid pests (Rhopalosiphum padi) and seed predation (of Helianthus annuus ). A set-up of 3 different experiments were placed in situ on 12 midfield islets. Pollination was more affected by local factors than landscape factors, although pollination success was improved by a smaller proportions of surrounding crop fields. Seed predation was higher on islets with more surrounding forest and also with more trees on the habitat, especially close to shrubs, compared to more open areas of habitat. Predation on aphids decreased on midfield islets with a larger amount of nearby forest but was positively affected by increasing local tree cover on the habitat. We show that managing semi-open habitats that are connected to other natural or semi-natural habitats can improve pollination success and biological pest and weed control, thus potentially increasing yield in surrounding crop fields. [ABSTRACT FROM AUTHOR]

It is generally accepted that selective logging significantly influences the vegetation coverage and habitat structures, but little is known about whether and how low intensity selective logging affects seed dispersal mediated by small rodents. In this study, we compared the differences in seed disperser composition and abundance as well as primary and secondary seed dispersal and predation of Quercus aliena var. acuteserrata by scatter-hoarding rodents in different aged forest (i.e., unlogged stands, stands in the second and fifth year after low intensity logging 150 stems per ha) in Huoditang Forest in the Qinling Mountains, China. We found that the rodent composition of stands in the second year after logging (large-bodied disperser Sciurotamias davidianus was absent) differed conspicuously from that of the other two stands. Selective logging reduced the abundance of rodents, seed removal rate, scatter–hoarded proportion, and seed dispersal distance during the second year after selective logging. However, no significant differences were found in the composition and abundance of rodents as well as their seed dispersal services between the unlogged stands and in stands during the fifth year after logging. In addition, the proportions of initially buried acorns were significantly lower in stands in the second year after logging compared with the other two types of stands, but after seed caching, the seed revisiting rates were lower in stands in the second year after logging compared with the other two types of stands. Rodent–mediated seed dispersal was lower in the second year after selective logging but it recovered to its initial level within five years. The dispersal distance was significantly lower in stands in the second year after logging compared with the distances (3.12 ± 0.23 m) in the unlogged forest stands (5.75 ± 0.41 m) and in stands in the fifth year after logging (4.44 ± 0.36 m). Therefore, selective logging in forests is likely to temporarily alter the composition of rodent communities, change seed dispersal services, and the capacity for plant movements. Number of years after selective logging is important for determining whether seeds are removed rapidly by potential dispersers, which can lead to different rates of seed removal, seed predation, scatter–hoarding, and survival, and eventually influence forest recovery after selective logging. [ABSTRACT FROM AUTHOR]

Prairie deer mice ( Peromyscus maniculatus bairdii ) are permanent residents of row-crop fields in the Midwestern United Sates, and may provide ecosystem services by regulating weed seed and waste grain populations. Seed predation is especially critical in the months of highest seed availability following crop harvest, and is dictated by population density and individual patterns of diet choice. We used a combination of spatial mark-recapture demographic and stable isotope dietary analyses to investigate the ecology of prairie deer mice during this critical over-winter period within corn and soybean agro-ecosystems of west-central Indiana. Winter prairie deer mouse populations were robust in the row-crop habitats we sampled, with densities typically > 13 individuals/ha but variable among trapping grids and throughout winter. Apparent survival of individuals also varied throughout winter (57–79% monthly survival rate), and mean over-winter (December–April) survival of adults was 21%. Winter diets were dominated by waste grain, with corn and soybean contributing 55% and 77% of diet for mice sampled in corn and soybean fields, respectively. Weed seeds contributed less (2–27%) to winter diets. Based on our results and published field metabolic rates, we estimate that prairie deer mice consume 6.3 kg/ha of waste corn and 7.1 kg/ha of waste soybean seeds during the non-growing season. Collectively, our results suggest that prairie deer mice make meaningful contributions to reducing waste-grain populations during winter in post-harvest row-crop fields, during a time of year when most other seed predators are inactive. [ABSTRACT FROM AUTHOR]

Seed predation may be an important ecosystem service for controlling glyphosate–resistant crop volunteers, which are a growing management concern in conventional cropping systems that rely heavily on pesticide based management. In the Midwest USA, prairie deer mice ( Peromyscus maniculatus ) are important seed predators, removing unwanted weed seeds and waste grain from the soil surface all year round. In this study, we examined how the spatial distribution of experimental maize ( Zea mays ) seed patches influenced overwinter foraging, mouse populations and waste grain removal in conventional crop fields. We predicted that (1) individual mice will increase foraging on maize waste grain in fields with many small maize seed patches compared to fields with a few large maize seed patches (functional response) and (2) more mice will forage in fields with many small seed patches than in fields with a few large seed patches (numerical response). We found mouse functional responses were not influenced by the spatial distribution of maize seed patches nor did mice respond numerically to seed addition in general. Mice did, however, remove 59–66% (94–106 kg ha −1 ) of the maize seeds, providing a valuable ecosystem service. Our work shows that prairie deer mice are able to remove large amounts of waste grain from the soil surface over winter, supporting the hypothesis that overwinter seed predation by mice can drastically reduce volunteer maize densities in conventional crop fields. Future research should further examine what management practices (such as practicing no-till) increase mouse abundance and foraging efficacy, so that management strategies that maximize seed predation can be developed. [ABSTRACT FROM AUTHOR]

Concerns exist over the continual decline of marula trees ( Sclerocarya birrea subsp. caffra ), a large ecologically and economically important tree species in southern Africa, primarily as a consequence of impact by African elephants ( Loxodonta africana ) and poor regeneration. We assessed changes to marula tree population structure in a protected area that was only recently opened to elephants. Jejane Private Nature Reserve (JPNR) has been subjected to elephants from the Greater Kruger National Park (Greater KNP) since 2013, as it was fenced off beforehand. A previous survey of the marula population in JPNR was done in 2009 and again in 2016. Therefore this study aimed to (i) assess elephant-induced impact and mortality levels on the previously surveyed JPNR marula tree population, (ii) compare these levels with previously recorded impact and mortality levels on marula trees across the Greater KNP, and (iii) assess marula seed predation and seedling recruitment in JPNR. The resurveyed marula population had declined by 23.8% post-elephant movement into JPNR, with the highest annual mortality rates (AMR) and elephant impact scores for trees in the 5–8 m height class. The JPNR marula tree AMR of 8.1% was higher than that of Greater KNP (4.6%). Only two marula seedlings were found across all transects, whilst 84.2% of all endocarps’ locules had seeds missing, with bite marks present on 42.3% of all endocarps. This suggests potential high levels of seed predation and a lack of seedling recruitment. The concern over the impact by elephants on adult marula trees is therefore escalated as a consequence of the lack of regeneration, primarily because of seed and seedling predation. Management policies should be focused on protection methods for individual trees, seedlings and seeds, together with a large scale artificial surface water management plan to manipulate herbivore densities and pressures on marula tree populations. [ABSTRACT FROM AUTHOR]

Seed mortality represents a substantial cost for plants and can have a large effect on plant reproductive fitness. Here we report evidence for pre-dispersal seed mortality by a novel mechanism: culm felling in female nut-seeded restios by rodents. We noted strong female-specific culm felling in the nut-fruited Cannomois congesta Mast. (Restionaceae) from the South Western Cape, South Africa. Camera-trap analysis showed that this culm felling is carried out by the striped mouse, Rhabdomys pumilio Spar. (Muridae) and is primarily aimed at obtaining ripe seeds held at the tips of female culms rather than eating the culm. All seeds acquired by R. pumilio were found to be consumed. We recorded a mean loss of 81% culms/seeds in affected female C. congesta plants in contrast to very few culm losses from males. This highly selective rodent behaviour is presumably due to detectable differences in the nutritional reward associated with terminal male/female inflorescences (large nut-like seeds vs. pollen). Pre-dispersal seed predation through culm felling could significantly reduce the fecundity of ant-dispersed restios such as C. congesta because fewer seeds manage to fall to ground where mutualistic ground foraging ants compete with rodents for seeds. Culm losses through felling could also have physiological and nutritional implications. Future research should explore the generality of this phenomenon amongst the Restionaceae, and quantify the associated physiological and reproductive costs. [ABSTRACT FROM AUTHOR]

Insect predation on seeds of forests species during the predispersal phase is a special case of plant-pest interaction in which, while plant survival and growth is not threatened, natural regeneration can be negatively affected. In the case of seeds with a high economic value, as is the case of nuts from the Mediterranean stone pine ( Pinus pinea L.), predispersal predation can also result in severe economic losses. The insect-seed relationship shows complex spatiotemporal dynamics, including patterns of dependency between fruit availability and fluctuations in insect population, occurrence of insect outbreaks, spatial contagion and masting habit. In the present study, we focus on the damage caused by a native pest, the Dioryctria mendacella Stgr. moth, to cones and seeds of P. pinea , a forest species showing a marked masting habit. We firstly identified those environmental and stand-level factors controlling the spatiotemporal pattern of damage by D. mendacella , as well as the self-regulatory effect that interannual variability in seed production could have on the population dynamics of the moth. In a second phase, we constructed a predictive phenomenological model to forecast the probability of cone damage in a given location, as well as the expected patterns of spatiotemporal spread and dispersion. Our results revealed a strong correlation between the probability of damage and crop size in a given year, pointing to a dependency between feeding resources and predator population. Additionally, the probability of damage is affected by the number of damaged cones observed in the previous year, indicating temporal contagion. Cone and seed damage is also affected by the temperature during different phases of the complex life-cycle of D. mendacella , which suggests that breakout processes are synchronized within the territory and linked to the occurrence of bumper crops and favorable climatic conditions. We detected that the level of infestation at a given location is related to site and environmental conditions, with no significant pattern of contagion/spreading from stands with high resource availability to those with low availability. Damage prediction under warmer climate scenarios reveals a counterbalance among favorable/unfavorable conditions for insect expansion and expected decline in cone production, resulting in only slight changes. [ABSTRACT FROM AUTHOR]

Soil seedbanks contribute to development of weed communities in agroecosystems and thus, understanding their regulation contributes to weed management strategies. In this context, the impacts of beneficial seed-consuming arthropods like carabids may contribute to sustainable long-term weed management. We were interested in assessing the spatial relationship between carabid beetles, weeds, and weed seeds in canola ( Brassica napus L.), one of the most widely grown crops in Canada. To do this, we collected spatially referenced count data representing the activity-density of seed predatory carabid species and data regarding weed density and weed seed density. We used Spatial Analysis by Distance Indices (SADIE) to explore spatial distributions of carabids in four commercial canola agroecosystems in western Canada. Carabids and weed populations were highly clustered. Moreover, there was significant spatial overlap between activity-density of carabids and patches of high weed density, with an association index, X, ranging between 0.40 and 0.71. Patterns of spatial association also became generally stronger with more advanced crop development. Our results suggest that presence of weedy patches of vegetation in cropped areas contributes to biodiversity by conserving populations of carabids, which also increases rates of weed seed predation. [ABSTRACT FROM AUTHOR]

We investigated the influence of seed-feeding beetles (Chrysomelidae, Bruchinae) and their parasitoids on the germination performance of two Fabaceae, Leucaena leucocephala and Senna multijuga. We collected 150 fruits per species in forest fragments in the city of Lavras, Minas Gerais, Brazil, between July and August 2020. Seeds were examined and separated into predated and non-predated categories. The predated category was divided into two subcategories: predated by Coleoptera (Bruchinae) (PCO) and predated in the presence of Coleoptera parasitoids (PARCO). The non-predated category was divided into artificially injured (AI), intact seeds without insect infestation (IS), and intact seeds with insect infestation (SIF). Seeds of S. multijuga and L. leucocephala germinated to 40% and 30%, respectively. PCO and PARCO seeds not only had a negative and restricting influence on S. multijuga germination (no germination) but also contributed to a large proportion of non-viable predated seeds (38%). PCO (7%) and PARCO (23%), on the other hand, improved L. leucocephala germination. This work represents one of the first attempt to evaluate the parasitoid effect on seeds germination. Our results contribute to a better understanding of the effect of herbivore predation and the presence of parasitoids on host plant seed germination, which can be critical to mother plant fitness depending on plant species. Further studies are necessary to determine the extend seed consumption by beetles and the presence of their parasitoids may facilitate or impair seed germination, and consequently plant fitness in other systems. [Display omitted] • We investigated the influence of beetles and their parasitoids on the seed germination performance of two plant species. • PCO and PARCO seeds had a negative influence on S. multijuga germination and caused non-viability to the majority of seeds. • PCO (7%) and PARCO (23%), on the other hand, improved L. leucocephala germination. • We helped to clarify how herbivore predation and the presence of their parasitoids affect their host plant germination. [ABSTRACT FROM AUTHOR]

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Abstract With a growing body of research dedicated to understanding earthworm seed preferences, we conducted a preliminary investigation of two previously unconsidered factors: seed density and previous earthworm egestion. We used no-choice feeding experiments with the common European earthworm Lumbricus terrestris L. and seed of the biennial forb Alliaria petiolata (M. Bieb) Cavara & Grande. Earthworm seed ingestion increased exponentially when available seed density was doubled (+305%) and was reduced when encountering seed that had previously been egested by another earthworm (−30%). Impacts of seed density and previous earthworm egestion have broader ecological implications for earthworm granivory behaviour and earthworm-plant interactions in natural and managed ecosystems. We recommend both factors as promising candidates for future experimentation. Highlights • Effects of seed density and previous egestion on earthworm granivory are unknown. • Ingestion increased exponentially with a doubling of available seed density. • Ingestion was reduced for seeds previously egested by another earthworm. • Seed density and previous egestion are promising candidates for future research. [ABSTRACT FROM AUTHOR]

• This is the first record of brood pollination by beetles other than weevils in Australia. Brood pollination is one of the more unusual ways in which plants reproduce. The plant has to trade off damage to its flowers and reduction in future offspring in exchange for the production of seeds. Brood pollination occurs along a continuum from parasitism to mutualism. In two closely related monocot species of Thysanotus in southwest Western Australia one autogamous species is parasitised by visiting beetles that eat the ovules and affect viable seed production. In the other species, which is normally buzz pollinated, visiting beetles can be facultative brood pollinators. In many cases, adults of brood pollinator mutualisms feed on nectar or more rarely pollen. The Thysanotus system is unusual, as the anthers of T. manglesianus are poricidal so pollen is not freely accessible to the beetle which is incapable of sonication and no nectar is produced. However the beetles damage the flowers and consume some pollen, which is necessary as the pollen will not be available unless the anther walls are breached. A beetle may lay an egg on a plant's ovary, where the hatched larva burrows through the ovary wall and eats the developing ovules. However, not all flowers receive an egg despite the flower being visited by beetles. Thus, when there is no bee pollinator, beetle visitation allows seed to be produced, albeit less than would be produced if the beetles were absent and a normal pollinator present. As this type of pollination interaction is unknown in other species of Thysanotus , it is not possible to decide if the brood pollination mutualism has developed from a parasitic relationship or the reverse. The autogamous species does not need a pollinator and always had a higher fruit set and fewer beetles than the population of the other species at a site where the more usual bee pollinator was absent. It may be that brood pollination mutualism is a development from a parasitic relationship. [ABSTRACT FROM AUTHOR]

Prescribed fire has been widely used as a fuel reduction tool and silvicultural treatment in Mediterranean forest ecosystems. However, other than the fact that fire may alter microsite conditions, little is known about the impact of prescribed burning on the natural regeneration of Spanish black pine ( Pinus nigra Arn. ssp. salzmanii ). In this study, we compared the effects of post dispersal seed predation, prescribed burning and vegetation treatment (brushing) on initial recruitment of Spanish black pine in both pure and mixed (with maritime pine, Pinus pinaster Ait.) stands during one year (2014) in the Cuenca Mountains (central-eastern Spain). Seedling recruitment in both pure and mixed stands was negatively affected by prescribed burning but was improved by the vegetation treatment. Post dispersal seed protection was an important factor for seed emergence and early survival success. Prescribed burning must be carefully planned in forest management aimed at regeneration. The influence of fire on natural regeneration should be taken into account for developing guidelines for the management of black pine forests, mainly in the Mediterranean Basin. [ABSTRACT FROM AUTHOR]

Omnivorous predators are key contributors to biocontrol, but the relative importance and interactive effects of ecological variables (e.g., habitat and prey- or plant-based foods) that impact their colonization, abundance, and/or function in crop fields are poorly understood. Here, we use immuno-marking to examine both activity density and consumption by omnivorous ground beetles in response to experimentally manipulated cover, weed seeds, and invertebrate prey. Vegetative cover increased per-capita seed predation by 73% compared with bare plots, validating existing correlative evidence that cover crops facilitate weed biocontrol. Interestingly, beetles responded differently to the main effects of seeds and prey. In both years, early season seed presence increased activity-density by 77%, while prey availability never influenced beetle activity. These data suggest that within-field habitat manipulation strategies such as cover crops improve biocontrol, not only by promoting increased activity of omnivores, but also by facilitating their function as seed predators on an individual-level. [ABSTRACT FROM AUTHOR]

Timber harvests that aim to promote oak ( Quercus ) regeneration may have indirect impacts on seedling recruitment by altering trophic interactions between oak and animals. For example, changes in habitat structure following harvest may alter the conditionally mutualistic relationship between oak and small mammal granivores like the gray squirrel ( Sciurus carolinensis ), eastern chipmunk ( Tamias striatus ) and white-footed mouse ( Peromyscus leucopus ) that act both as acorn predators and as dispersers. Over 4 years (2010–2013), we tracked the fate of a total of 8000 tagged acorns placed beneath black ( Quercus velutina ) and white oaks ( Quercus alba ) at 5 control (unharvested) sites and 5 sites where the midstory was removed as part of a three-phase shelterwood harvest in an oak-dominated forest in southern Indiana, USA. We found that acorns in harvested sites were more likely to be taken by granivores and were less likely to survive the winter, resulting in an overall 67% reduction in seed dispersal effectiveness (SDE). Harvested sites had more vegetative cover and coarse woody debris in the understory, providing increased cover from aerial predators and potentially facilitating greater acorn removal and a higher probability of cache recovery. Reduced seed dispersal effectiveness following midstory removal has potential to slow accumulation of oak regeneration prior to overstory removal and therefore to reduce the effectiveness of shelterwood treatments in promoting future oak dominance in harvested stands. Augmentation of shelterwoods with prescribed fire or other treatments to reduce understory density may counter this effect. [ABSTRACT FROM AUTHOR]

The introduced black locust ( Robinia pseudoacacia ) has become an invasive plant species in Europe. The introduction of alien plants such as the black locust may modify ecosystem composition and functioning. In response to the presence of a potential host plant, herbivores can adapt and shift to the consumption of the new host plant. In Eastern-Central Europe, the seed predator Bruchophagus robiniae (Hymenoptera: Eurytomidae ) is an important consumer of black locust seeds which presumably shifted from its formerly host species to black locust. We tested the influence of host plant abundance on a seed predator – parasitoid community. We found that the seed predator B. robiniae was present in higher numbers in woodlots than in small patches of black locust. The density of the specialist parasitoid Mesopolobus sp. was lower in woodlots than in small patches, while the generalist parasitoid Eupelmus urozonos was evenly distributed between woodlots and small patches of black locust. We found that parasitoid species are influenced by the patch size of host plants, thus characteristics of introduced host plants can also manifest in higher trophic levels. [ABSTRACT FROM AUTHOR]

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Plant–antagonist interactions shape the structure, composition and dynamics of plant communities and ecosystems. Due to their key importance, much research has been advocated to evaluate anthropogenic habitat loss and fragmentation effects on plant–antagonist interactions but no clear response patterns have arisen. Even recent quantitative reviews have failed to provide consistent generalizations. Here we conduct the first phylogenetically independent meta-analysis along with a traditional meta-analytical approach. We examined whether characteristics of the interaction, the fragmented landscape, and methodological approaches modulate the magnitude of effects. Traditional meta-analysis showed that plants within habitat fragments suffer on average less damage from antagonists. However, when incorporating the phylogenetic relationships among plants, the overall effect and the particular effects of moderators became non-significant. Interestingly, we found a strong and consistent trend between both meta-analytical approaches in the overall effect of habitat fragmentation on folivory elicited by insects. This implies the first genuine fragmentation effect that transcends the phylogeny of plants and is not undermined by statistical problems of pseudoreplication. Decreased insect folivory will favor certain plant species, especially those with acquisitive resource use traits such as pioneer and exotic invasive, thereby affecting plant community composition in fragmented habitats. Here, we highlight the importance of incorporating the phylogeny in meta-analytical contexts. Our results imply that current studies worldwide represent a phylogenetically-conserved sample of fragmentation effects on plant-antagonist interactions. Thus, more studies on distantly phylogenetically-related plants are needed to have a broader, more representative, sample of responses across angiosperms. [ABSTRACT FROM AUTHOR]

• Density-dependent effects influence plant reproduction output in restoration sites. • Increasing tree density enhances fruit set, but also the abundance of pre-dispersal seed predators. • Seed germination rates represent the net effect of plant density on plant reproduction. • The influence of density-dependent effects must be accounted during restoration planning and management. Plants are involved in different interactions with animals that may have contrasting effects on their reproductive output. However, as multitrophic interactions are resource-mediated and density-dependent, the frequency at which these interactions occur is modulated by the demographical characteristics of the populations of interacting species. For example, while plant aggregation may increase pollinator attraction and consequently, pollination success, an increased seed set may also attract more seed predators. Therefore, the intensity of pollination and seed predation events may affect plant population dynamics. Although multitrophic plant-animal interactions are crucial for maintaining biodiversity in terrestrial ecosystems, they have seldom been studied together, especially in restored habitats. To fill this gap, we used five restoration sites that used Inga vera trees at different densities to evaluate how density-dependent effects impact fruit set, seed predation, seed germination rate and the number of viable germinated seeds (i.e., the net effect of pollination and seed predation). Using structural equation models to assess the isolated effects of each predictor variable in each response variable and the cascading effects of each response variable on another, we found that density-dependent effects influenced I. vera reproduction. While I. vera trees in high density presented higher fruit set and seed predation rates, trees in low-density plantations presented lower fruit set, but seed predators consumed fewer seeds. The contrasting results of final seed germination rates revealed that density-dependent effects are pivotal to plant establishment and population dynamics. We argue that the study of density-dependent multitrophic plant-animal interactions is essential to guarantee that the efforts done in restoration initiatives can turn into successful results in terms of restoring ecosystem structure and stability. [ABSTRACT FROM AUTHOR]

Many kinds of pests can reduce seed production. Some directly attack seeds before they are released, and some are hosted by the fruit and impact seed ripening and viability indirectly. Pre-dispersal seed mortality may have strong effects on plant population dynamics and evolution. Our goals were to determine to what extent insect-mediated pre-dispersal seed mortality contributes to population-level declines of cornflower, Centaurea cyanus L. We recorded occurrence and abundance of seed-feeding insects on flower heads in twelve cornflower populations. We measured flower head size, number of disc florets, seed production, and seed viability and germination. Larger flower heads had proportionally fewer healthy seeds. Although we observed no visible damage to the C. cyanus seed, the presence of gall midge (Cecidomyiidae) larvae inside the flower head correlated with four times fewer viable seeds. It seems that gall midges could have a significant impact on ovule fertilization, seed abortion and viability of fully developed cornflower seeds. The higher rate of aborted seeds in the presence of gall midge larvae could have been because the larvae extracted resources from the seeds, or because the larvae repelled pollinators. The viability of apparently healthy seeds was 40% lower in flower heads that contained larvae and/or aborted seed. Insect-mediated pre-dispersal mortality could select against evolution toward larger flower head, and have detrimental consequences on seed number, viability and germination, all of which could limit the spread of C. cyanus populations. [ABSTRACT FROM AUTHOR]

The masting phenomenon along with its accompanying suite of seedling adaptive traits has been well studied in forest trees but has rarely been examined in desert shrubs. Blackbrush ( Coleogyne ramosissima ) is a regionally dominant North American desert shrub whose seeds are produced in mast events and scatter-hoarded by rodents. We followed the fate of seedlings in intact stands vs. small-scale disturbances at four contrasting sites for nine growing seasons following emergence after a mast year. The primary cause of first-year mortality was post-emergence cache excavation and seedling predation, with contrasting impacts at sites with different heteromyid rodent seed predators. Long-term establishment patterns were strongly affected by rodent activity in the weeks following emergence. Survivorship curves generally showed decreased mortality risk with age but differed among sites even after the first year. There were no detectable effects of inter-annual precipitation variability or site climatic differences on survival. Intraspecific competition from conspecific adults had strong impacts on survival and growth, both of which were higher on small-scale disturbances, but similar in openings and under shrub crowns in intact stands. This suggests that adult plants preempted soil resources in the interspaces. Aside from effects on seedling predation, there was little evidence for facilitation or interference beneath adult plant crowns. Plants in intact stands were still small and clearly juvenile after nine years, showing that blackbrush forms cohorts of suppressed plants similar to the seedling banks of closed forests. Seedling banks function in the absence of a persistent seed bank in replacement after adult plant death (gap formation), which is temporally uncoupled from masting and associated recruitment events. This study demonstrates that the seedling establishment syndrome associated with masting has evolved in desert shrublands as well as in forests. [ABSTRACT FROM AUTHOR]

The mutualistic interaction between scatter-hoarding rodents and seed plants have a long co-evolutionary history. Plants are believed to have evolved traits that influence the foraging behavior of rodents, thus increasing the probability of seed removal and caching, which benefits the establishment of seedlings. Tannin and nutrient content in seeds are considered among the most essential factors in this plant-animal interaction. However, most previous studies used different species of plant seeds, rendering it difficult to tease apart the relative effect of each single nutrient on rodent foraging behavior due to confounding combinations of nutrient contents across seed species. Hence, to further explore how tannin and different nutritional traits of seed affect scatter-hoarding rodent foraging preferences, we manipulated tannin, fat, protein and starch content levels, and also seed size levels by using an artificial seed system. Our results showed that both tannin and various nutrients significantly affected rodent foraging preferences, but were also strongly affected by seed size. In general, rodents preferred to remove seeds with less tannin. Fat addition could counteract the negative effect of tannin on seed removal by rodents, while the effect of protein addition was weaker. Starch by itself had no effect, but it interacted with tannin in a complex way. Our findings shed light on the effects of tannin and nutrient content on seed removal by scatter-hoarding rodents. We therefore, believe that these and perhaps other seed traits should interactively influence this important plant-rodent interaction. However, how selection operates on seed traits to counterbalance these competing interests/factors merits further study. [ABSTRACT FROM AUTHOR]

Invertebrate weed seed predation is an important component of weed seed loss in agricultural fields. This study investigated the role of seed imbibition on the selection and consumption of the seeds of seven common agricultural weed species by Harpalus pensylvanicus De Geer, a granivorous carabid beetle (Coleoptera: Carabidae) that is found throughout North America. The volatile organic compounds released by ambient dry and imbibed weed seeds were quantified, and Y-tube bioassays were conducted to determine if H . pensylvanicus individuals responded to volatile compounds released from weed seeds. H . pensylvanicus individuals were found to consume higher masses of seeds for each weed species examined in imbibed versus ambient dry trials ( P < 0.05). Larger seeded species had the greatest increase in mass consumption between dry seed and imbibed seed trials. The seeds from the seven weed species examined released carbon dioxide and ethylene when ambient dry and imbibed, but H . pensylvanicus adults were only able to detect weed seeds through olfaction when volatile release was highest as a result of imbibition. These results demonstrate that seed imbibition is important in determining seed detection and consumption by invertebrates and may affect seed banks in agricultural fields. [ABSTRACT FROM AUTHOR]

Avoiding the conversion of tropical production forests to non-forest land uses is a forestry and conservation priority, and is contingent on successful regeneration of commercially important species. The underlying ecological processes that facilitate regeneration, however, are poorly understood. Perhaps as a result, timber yields after regeneration can be lower than expected. Hunting is widespread in timber concessions, and may threaten regeneration by disrupting the various processes facilitated by wildlife. Vertebrate seed dispersers are often heavily hunted, resulting in reduced seed movement for many species and a shift in community composition to favor those plants dispersed by small animals and abiotic means. Timber species with large seeds and fleshy fruit are at particular risk for dispersal and recruitment failure. Hunting also alters granivore communities, resulting in increased predation on species favored by insects and small rodents, and changing the spatial template of seed predation, with detrimental effects on many timber species. Large vertebrate herbivores decline with hunting pressure, resulting in the modification of plant competitive interactions. This is disadvantageous to several traits that are common among timber trees, including relatively slow growth and high wood density. A lack of appreciation for – and management of – these interactions could threaten forest biodiversity, limit future timber production, and increase the likelihood of forest conversion for other land uses. In this review, I highlight the plant-animal interactions that could influence timber regeneration in tropical forests, as well as how these processes might be expected to change under hunting pressure. The review concludes with recommendations for management and future research priorities. [ABSTRACT FROM AUTHOR]

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Modern Neotropical rainforests are characterized by the high intensity and host specificity with which insects feed on plants. Previous studies have shown that, during the middle–late Paleocene, the leaves of the early evolving Neotropical rainforests of tropical South America were heavily herbivorized by insects. Yet, less attention has been given to insect damage found on fossil fruits and seeds, despite the host specialization of many disseminule predators in modern forests. Here, we present and describe borings found on a fruit compression fossil of cf. Cocos (coconut) from the middle–late Paleocene Cerrejón Formation (58–60 Ma) of Colombia. We interpret the borings as constructed by palm seed beetles (Chrysomelidae: Bruchinae: Pachymerina) based on size, number, position, plant reaction tissue, and plant host selection. This occurrence provides the earliest record of an ecological interaction between seed beetles and palms, suggesting that this host-specific interaction has been consistently maintained for several tens of millions of years. • A fossil cf. Cocos sp. fruit, from the Cerrejón Formation, evidences insect borings. • The borings are consistent with the feeding behavior of palm bruchines (Pachymerina). • The borings represent the earliest association between palm bruchines and palms. • Palm bruchines and palms have interacted since, at least, the middle-late Paleocene. [ABSTRACT FROM AUTHOR]

• Canopy openness differs among individual trees within and across species. • Tree canopy openness variation influences seed dispersal and predation by rodents. • Seeds under larger canopies are more likely to be removed and dispersed further. • Individual variation in canopy openness leads to variation in seedling regeneration. • Crown pruning can promote seed dispersal by rodents and natural seedling regeneration. Scatter-hoarding rodents are important seed predators and dispersers in various forest ecosystems and significantly influence the seed fate and seedling regeneration of many tree species. Canopy openness is believed to have an important influence on the foraging behavior of scatter-hoarding rodents, mainly because of the variation in predation risk between open and canopy microsites. Most of the current studies have mainly focused on the spatial variation in canopy openness within a forest or on comparisons among forests; however, the question of how variation in canopy openness at the individual tree scale affects seed-rodent interaction has received little attention, although tree-to-tree variation in canopy openness is ubiquitous. In this study, we measured the individual canopy openness of 45 trees belonging to three species in a subtropical forest, and compared seed dispersal and predation by rodents under the selected trees by labeling and tracking 4,500 seeds. Our results showed that canopy openness differed among individual trees both within and across species. More importantly, our results proved that individual tree variation in canopy openness significantly affected seed dispersal and predation by rodents, although not all species followed a consistent pattern. Seeds under trees with larger canopy openness were more likely to be removed rather than eaten in situ and dispersed farther. Our study highlights the pattern that individual tree characteristics (e.g., canopy openness) have profound effects on rodent-mediated seed dispersal services, which may further lead to tree-to-tree variation in seed fate and seedling regeneration. Our results also provide important implications for forest conservation and management: crown pruning can promote seed dispersal by rodents and natural seedling regeneration. [ABSTRACT FROM AUTHOR]

Abstract: Crotalaria pallida (Fabaceae) is a pantropical plant with extrafloral nectaries (EFNs) near the reproductive structures. EFN-visiting ants attack and remove arctiid moth Utetheisa ornatrix larvae, the main pre-dispersal seed predator, but the impact of ants on C. pallida fitness is unknown. To assess this impact, we controlled ant presence on plants and evaluated the reproductive output of C. pallida with and without ants. Predatory wasps also visit EFNs, prey upon U. ornatrix larvae, and may be driven out by ants during EFN feeding. Does this agonistic interaction affect the multitrophic interaction outcome? We found it difficult to evaluate the effect of both visitors because cages excluding wasps affect plant growth and do not allow U. ornatrix oviposition. Therefore, we verified whether ant presence inhibited wasp EFN visitation and predicted that (1) if ants confer a benefit for C. pallida, any negative effect of ants on wasps would be negligible for the plant because ants would be the best guardians, and (2) if ants are poor guardians, they would negatively affect wasps and negatively impact the fitness of C. pallida. Surprisingly, we found that the number of seeds/pods significantly increased, ca. 4.7 times, after ant removal. Additionally, we unexpectedly verified that controls showed a higher percentage of herbivore bored pods than ant-excluded plants. We found that wasps spent less time visiting EFNs patrolled by ants (ca. 299 s less). These results support our second prediction and suggest that the outcome of multitrophic interactions may vary with natural enemy actors. [Copyright &y& Elsevier]

Highlights: [•] Complete defaunation is not a prerequisite to alter the strength of plant-animal interactions. [•] Hunting reduced the mean seed dispersal distances of mammal-dispersed tree species. [•] Hunted forest had reduced rates of seedling herbivory and lower above-ground biomass. [•] Modification of plant-animal interactions could compromise forest carbon storage potential. [ABSTRACT FROM AUTHOR]

Highlights: [•] Defaunation of large mammals may have strong impact on plant communities. [•] We monitor seedling species richness, diversity and functional groups during 36 months in a semi-defaunated Atlantic forest. [•] We fail to detect any changes in the plant community after mammal exclusion. [•] The high abundance of primates, and the long history of defaunation may already have selected the species in this community. [ABSTRACT FROM AUTHOR]

Highlights: [•] Defaunation is associated with lower diversity. [•] Defaunation leads to lower seed dispersal, seed predation, and herbivory rates. [•] Potential for functional compensation among vertebrates appears limited. [ABSTRACT FROM AUTHOR]