Foliar damage modifies floral attractiveness to pollinators in Alstroemeria exerens

Pollination is a requisite for sexual reproduction in plants and its success may determine the reproductive output of individuals. Pollinator preference for some floral designs or displays that are lacking or poorly developed in focal plants may constrain the pollination process. Foliar herbivory may affect the expression of floral traits, thus reducing pollinator attraction. Natural populations of the Andean species Alstroemeria exerens (Alstromeriaceae) in central Chile show high levels of foliar herbivory, and floral traits show phenotypic variation. In the present field study, we addressed the attractive role of floral traits in A. exerens and the effect of foliar damage on them. Particularly, we posed the following questions: (1) Is there an association between floral display and design traits and the number and duration of pollinator visits? and (2) Does foliar damage affect the floral traits associated with pollinator visitation? To assess the attractiveness of floral traits for pollinators, we recorded the number and duration of visits in 101 focal plants. To evaluate the effects of foliar damage on floral traits, 100 plants of similar size were randomly assigned to control or damage groups during early bud development. Damaged plants were clipped using scissors (50% of leaf area) and control plants were manually excluded from natural herbivores (<5% of leaf area eaten). During the peak of flowering, we recorded the number of open flowers, and estimated corolla and nectar guide areas. The number and duration of pollinator visits was statistically associated with floral design and display traits. Plants with larger displays, corollas and nectar guide areas received more visits. Visits lasted longer as display increases. In addition, foliar damage affected attractive traits. Damaged plants had fewer open flowers and smaller nectar guide areas. We conclude that foliar damage affects plant attractiveness for pollinators and hence may indirectly affect plant fitness.     

Production of food bodies on the reproductive organs of myrmecophytic Macaranga species (Euphorbiaceae): effects on interactions with herbivores and pollinators

In protective ant–plant mutualisms, plants offer ants food (such as extrafloral nectar and/or food bodies) and ants protect plants from herbivores. However, ants often negatively affect plant reproduction by deterring pollinators. The aggressive protection that mutualistic ants provide to some myrmecophytes may enhance this negative effect in comparison to plant species that are facultatively protected by ants. Because little is known about the processes by which myrmecophytes are pollinated in the presence of ant guards, we examined ant interactions with herbivores and pollinators on plant reproductive organs. We examined eight myrmecophytic and three nonmyrmecophytic Macaranga species in Borneo. Most of the species studied are pollinated by thrips breeding in the inflorescences. Seven of eight myrmecophytic species produced food bodies on young inflorescences and/or immature fruits. Food body production was associated with increased ant abundance on inflorescences of the three species observed. The exclusion of ants from inflorescences of one species without food rewards resulted in increased herbivory damage. In contrast, ant exclusion had no effect on the number of pollinator thrips. The absence of thrips pollinator deterrence by ants may be due to the presence of protective bracteoles that limit ants, but not pollinators, from accessing flowers. This unique mechanism may account for simultaneous thrips pollination and ant defense of inflorescences.     

Influence of leaf herbivory,root herbivory,and pollination on plant performance in Cucurbita moschata

Abstract 1. Plants experience herbivory on many different tissues that can affect reproduction directly by damaging tissues and decreasing resource availability, or indirectly via interactions with other species such as pollinators. 2. This study investigated the combined effects of leaf herbivory, root herbivory, and pollination on subsequent damage, pollinator preference, and plant performance in a field experiment using butternut squash (Cucurbita moschata). Leaf and root herbivory were manipulated using adult and larval striped cucumber beetles (Acalymma vittatum F.), a cucurbit specialist. 3. Leaf herbivory reduced subsequent pistillate floral damage and powdery mildew (Sphaerotheca fuliginea) infection. In spite of these induced defences, the overall effect of leaf herbivory on plant reproduction was negative. Leaf herbivory reduced staminate flower production, fruit number, and seed weight. In contrast, root herbivory had a minimal impact on plant reproduction. 4. Neither leaf nor root herbivory altered pollinator visitation or floral traits, suggesting that reductions in plant performance from herbivory were as a result of direct rather than indirect effects. In addition, no measured aspect of reproduction was pollen limited. 5. Our study reveals that although leaf herbivory by the striped cucumber beetle can protect against subsequent damage, this protection was not enough to prevent the negative impacts on plant performance.     

Effects of different herbivores on an actinorhizal species in Northwest Patagonia

Above-ground herbivory has a direct impact on plant life cycles, particularly at more sensitive stages, due to reduction of vegetative biomass. However, this effect may not be negative if it results in net biomass compensation. As sapling stage could be the best stage for native species to be outplanted, understanding the impact of aboveground herbivory on tree saplings is necessary for restoration purposes. We studied the effect of herbivory on saplings of Ochetophila trinervis (Rhamnaceae), a native woody species from North-west Patagonia, which forms an actinorhizal symbiosis with the N₂-fixing actinobacteria Frankia. This tree species has the potential to be used for recovering degraded lands. Nevertheless, there is a perplexing contradiction between the high seed output of O. trinervis and the scarcity of saplings in the field. For 4 months, 1-year-old O. trinervis saplings were exposed to aboveground herbivory by generating different protection degrees (unprotected, protected against some kind of walking herbivores—protected saplings; and protected against all kind of walking herbivores—excluded saplings). The impact of herbivores over sapling survival was minimal (92?±?3%, mean?±?SE) and it was similar among saplings exposed to different protection degrees. The highest frequency of foliar damage in excluded saplings suggests the attack of flying herbivores. The increased emergence of new sprouts and root length growth in saplings highly damaged by herbivores (about three fold and two fold higher than in excluded saplings, respectively), evidenced the capacity of O. trinervis to develop a compensatory growth. The results contradict the assumption that herbivory explains the low density of saplings despite high seed production. Given the high-sapling survival and biomass compensation of O. trinervis after herbivory, we suggest that this species might be appropriate for restoration of degraded areas in the region.     

Demographic effects of large, introduced herbivores on a long-lived endemic plant

The introduction of alien ungulates is a major threat for the survival of endangered plants, especially in island ecosystems. However, very few studies have investigated the potential damage of large herbivores on plant diversity in Mediterranean protected areas. In this study, we describe the population structure and the long-term dynamics of the main populations of the Sardinian narrow endemic Centaurea horrida Bad. (Asteraceae), by means of permanent plots where individual plants were tagged and monitored through 6?years (2004?C2009). We monitored this endangered plant at three sites: two were protected areas where introduced and feral ungulates are present, and the other one was a non-protected site without introduced ungulates. We found that adults and saplings were more abundant at the non-protected site. Through matrix models, we also highlighted that the non-protected population showed the highest population growth rate. Finally, by means of an exclusion experiment for ungulates at one protected site, we demonstrated that herbivores had a negative effect on the survival of seedlings and adult plants, and reduced the stochastic population growth rate. An LTRE analysis showed that differences in the survival, especially of adult individuals, had the highest responsibility in explaining the higher population growth rate when herbivores are excluded. Our study constitutes a clear example on how the protection of alien large herbivores can have opposite effects on the conservation of an endangered plant. Some management options are proposed, and the urgent need of manipulative experiments on species-specific interactions between protected plants and alien herbivore species is invoked.     

What works for threatened species recovery? An empirical evaluation for Australia

Despite the growing numbers of threatened species and high levels of spending on their recovery worldwide, there is surprisingly little evidence about which conservation approaches are effective in arresting or reversing threatened species declines. Using two government data sets, we examined associations between population trends for 841 nationally-threatened terrestrial species in Australia, and four measures of conservation effort: (a) how much their distribution overlaps with strictly protected areas (IUCN I–IV), (b) and other protected areas (IUCN V–VI), (c) the number of recovery activities directed at the species, and (d) numbers of natural resource conservation activities applied in areas where populations of the threatened species occur. We found that all populations of 606 (72%) species were in decline. Species with greater distributional overlap with strictly protected areas had proportionately more populations that were increasing or stable. This effect was robust to geographic range size, data quality differences and extent of protection. Measures other than strictly protected areas showed no positive associations with stable or increasing trends. Indeed, species from regions with more natural resource conservation activities were found to be more likely to be declining, consistent with differential targeting of such generalised conservation activities to highly disturbed landscapes. Major differences in trends were also found among the different jurisdictions in which species predominantly occurred, which may be related to different legislative protections against habitat destruction. Although we were not able to test causation, this research corroborates other evidence that protected areas contribute to the stabilization or recovery of threatened species, and provides little empirical support for other conservation approaches.     

Effectiveness of a protected areas network in the conservation of Tamarindus indica (Leguminosea–Caesalpinioideae) in Benin

In the absence of effective conservation of its wild relatives, exploitation of a species could lead to genetic depletion. Research on how well do protected areas contribute to the conservation of plant species subject to human exploitation is still limited. The potential niche of Tamarindus indica (tamarind) was evaluated and the contribution of the protected areas network (PAN) of Benin to its conservation was assessed. The maximum entropy approach was used to model the ecological niche of the species, and forest inventories were used to address its population structure. To test its effectiveness, the PAN map was overlapped with the habitat suitability map of the species, and its population structures in protected versus unprotected areas were compared. Tamarindus natural populations were confined to the Sudanian and Sudano‐Guinean regions. The species populations in the Sudanian region appeared well represented in protected areas in contrast to those in the Sudano‐Guinean region. Results showed a positive effect of protected areas on juvenile density but a weak effect on adult density and current size‐class distribution. Protection seemed to be unlikely to ensure the long‐term persistence of the species. Cryopreservation, assisted recruitment and artificial enrichment of tamarind stands are recommended to ensure the long‐term persistence of the species.     

Effects of floral herbivory on foraging behaviour of bumblebees and female reproductive success in Pedicularis gruina (Orobanchaceae)

The effects of floral herbivores on floral traits may result in alterations in pollinator foraging behaviour and subsequently influence plant reproductive success. Fed-upon plants may have evolved mechanisms to compensate for herbivore-related decreased fecundity. We conducted a series of field experiments to determine the relative contribution of floral herbivores and pollinators to female reproductive success in an alpine herb, Pedicularis gruina, in two natural populations over two consecutive years. Experimental manipulations included bagging, hand supplemental, geitonogamous pollination, and simulated floral herbivory. Bumblebees not only avoided damaged flowers and plants but also decreased successive visits of flowers in damaged plants, and the latter may reduce the level of geitonogamy. Although seed set per fruit within damaged plants was higher than that in intact plants, total seed number in damaged plants was less than that in intact plants, since floral herbivory-mediated pollinator limitation led to a sharp reduction of fruit set. Overall, the results suggest that resource reallocation within inflorescences of damaged plants may partially compensate for a reduction in seed production. Additionally, a novel finding was the decrease in successive within-plant bumblebee visits following floral herbivory. This may increase seed quantity and quality of P. gruina since self-compatible species exhibit inbreeding depression. The patterns of compensation of herbivory and its consequences reported in this study give an insight into the combined effects of interactions between floral herbivory and pollination on plant reproductive fitness.     

Contrasting effects of herbivory on plant size and reproductive performance in two populations of the Critically Endangered species,Euphorbia clivicola R. A. Dyer

Euphorbia clivicola R.A. Dyer is a Critically Endangered Northern Province endemic confined to two populations that have declined drastically over the last decade. One population is protected within a Nature Reserve, while the other occurs in a peri-urban area. In order to determine the causes of the population declines, herbivory damage to plants in both the protected and urban populations was quantified and the effects of herbivory on various aspects of the population biology were assessed. Mountain reedbuck are believed to have been responsible for the herbivory in the protected population. Herbivory on the above-ground branches probably caused the small sizes of protected plants. These were on average less than half the size of urban plants. Herbivory caused a reduction in the number of flowers and fruit produced per protected plant and may have prevented the maturation of flowers into fruit, thereby reducing the total regenerative output of the population. An eight-year absence of fire had resulted in the build-up of a dense moribund grass layer. The selection of E. clivicola plants by mountain reedbuck may therefore have been due to their relatively high nutritional value and accessibility in the thick moribund grass layer. Fencing off the population to prevent entry of herbivores, and implementing a more suitable fire management programme is recommended, as is the adoption of a new IUCN status for the species of Critically Endangered (CR A1).     

Estimation of dieback process caused by herbivory in an endangered root-sprouting shrub species,Paliurus ramosissimus (Lour.) Poir., using a shoot-dynamics matrix model

Mortality, a critical parameter for population dynamics, is difficult to measure in long-lived trees or clonal herbaceous species because of the extremely low frequency of deaths. A model based on shoot recruitment would be helpful to estimate the population fate of species without a sufficient number of observed deaths. Existing matrix models are applicable to the dynamics of physiologically independent shoots, but not to physiologically dependent ones. We developed a shoot-dynamics model for plants with physiologically-dependent shoots, and used the model to estimate the effects of herbivory and conservation measures on the dynamics of a long-lived, shoot-sprouting shrub species, Paliurus ramosissimus (Rhamnaceae). Two populations of the endangered shrub have been severely damaged by herbivory by sika deer. The damage was mainly to new sprouting shoots. No deaths of individual plants were observed during an 8-year survey, and we could not estimate mortality. Thus, prediction of population dynamics based on births and deaths of individuals was impossible. Because P. ramosissimus is a shoot-sprouting species, we instead estimated the decline of individuals using a shoot-dynamics model. Using this model, we estimated the time to an 80 % decrease in shoot number per individual in the two populations at 37.8 and 37.2 years. These lengths suggest an immediate need for conservation measures to prevent herbivory even though no death of any individual was observed in the field survey. The estimated recovery times from the herbivory damage were 28.7 and 29.2 years if herbivory of new shoots is completely prevented by conservation measure.     

Herbivory alters the expression of a mixed-mating system

The direct and indirect effects of vegetative herbivory on the mating system of Impatiens capensis were analyzed through a survey of herbivory in natural I. capensis populations and manipulation of leaf damage in the field. Across 10 wild populations of I. capensis proportion of cleistogamous flowers had a significant positive exponential relationship with natural levels of herbivory. Similarly, experimental leaf damage increased the proportion of flowers and seeds that were cleistogamous. Leaf damage also reduced the biomass of cleistogamous progeny more severely relative to that of chasmogamous progeny. The cumulative effect of leaf damage was to increase plant reliance on fitness derived from cleistogamous progeny. Leaf damage indirectly affected mating system traits by reducing chasmogamous flower size, leading to a reduction in pollinator visitation. Under these experimental conditions, herbivory did not significantly reduce the number of simultaneously open flowers and potential for geitonogamy, nor did it result in significant changes in the composition of the pollinator fauna. These findings are among the first to demonstrate that herbivory has consequences for mating system and should be considered a factor shaping mating system evolution.     

Population size, pollination and reproductive success in two endangered Genista species

Habitat fragmentation often leads to small and isolated plant populations as well as decreased habitat quality. These processes can fundamentally disrupt the interactions between plants and pollinators and decrease reproductive success. This concerns especially self-incompatible, non-clonal species that depend on pollination for successful reproduction.In two rare and endangered heathland plant species, Genista anglica and G. pilosa, we examined pollination and reproduction in relation to population size. Eight populations of G. anglica and ten populations of G. pilosa were surveyed in the vicinity of Bremen, NW-Germany. We counted the visits of pollinators (honeybees, bumblebees, and other insects) and determined the reproductive output of the observed shoots.Contrary to our expectation to find increased pollinator visitation rates in larger populations of both Genista species, the number of flower-visiting insects was unrelated to the number of flowering shoots. Increasing shoot length had a positive and increasing temperature a negative impact on the number of visiting honeybees and bumblebees. Despite the general absence of population size effects on pollinator numbers, the number of fruits and seeds in G. anglica increased with increasing population size. Fruit and seed set in G. pilosa were negatively related to the number of ‘other insects’. Our field observations showed that larger populations of both Genista species flowered earlier than smaller populations and much earlier than reported in the literature. Flowering in large populations therefore tends to coincide less well with pollinator abundance, and this may cause a disruption of the temporal coincidence between flowering phenology and pollinator activity.     

Are there contrasted impacts of urbanization and land uses on population persistence? The case of Teucrium pseudochamaepitys, an endangered species in Southern France

Among the endangered flora of the Mediterranean basin, Teucrium pseudochamaepitys, endemic Lamiaceae, is threatened by human activities. The threats are even more important that its distribution in Mediterranean France is very limited. This study was based on the comparison of nine sites urbanized or impacted by other human activities. Particularly, the associated plant community, the density and reproductive parameters of the study species, and pollinator activities were compared to asset the effect of urbanization and land use changes on the local population persistence. Interestingly, in urban sites, the result shows more ruderal species and a higher density of T. pseudochamaepitys due to clonal growth. Surprisingly, reproductive success is low in each site despite an effective insect pollination. However, diversity of pollinators is lower in urban sites. Effects are thus contrasted considering urbanization and land use changes. Changes in land uses lead to closing landscape which threaten short term persistence of populations due to competition while the loss of pollinator diversity may impact urban populations over the long term only.     

Effects of above- and belowground herbivory on growth,pollination, and reproduction in cucumber

Plants experience unique challenges due to simultaneous life in two spheres, above- and belowground. Interactions with other organisms on one side of the soil surface may have impacts that extend across this boundary. Although our understanding of plant–herbivore interactions is derived largely from studies of leaf herbivory, belowground root herbivores may affect plant fitness directly or by altering interactions with other organisms, such as pollinators. In this study, we investigated the effects of leaf herbivory, root herbivory, and pollination on plant growth, subsequent leaf herbivory, flower production, pollinator attraction, and reproduction in cucumber (Cucumis sativus). We manipulated leaf and root herbivory with striped cucumber beetle (Acalymma vittatum) adults and larvae, respectively, and manipulated pollination with supplemental pollen. Both enhanced leaf and root herbivory reduced plant growth, and leaf herbivory reduced subsequent leaf damage. Plants with enhanced root herbivory produced 35% fewer female flowers, while leaf herbivory had no effect on flower production. While leaf herbivory reduced the time that honey bees spent probing flowers by 29%, probing times on root-damaged plants were over twice as long as those on control plants. Root herbivory increased pollen limitation for seed production in spite of increased honey bee preference for plants with root damage. Leaf damage and hand-pollination treatments had no effect on fruit production, but plants with enhanced root damage produced 38% fewer fruits that were 25% lighter than those on control plants. Despite the positive effect of belowground damage on honey bee visitation, root herbivory had a stronger negative effect on plant reproduction than leaf herbivory. These results demonstrate that the often-overlooked effects of belowground herbivores may have profound effects on plant performance.     

Herbivory Differentially Affects Plant Fitness in Three Populations of the Perennial Herb Lythrum salicaria along a Latitudinal Gradient

Herbivory can negatively and selectively affect plant fitness by reducing growth, survival and reproductive output, thereby influencing plant population dynamics and evolution. Latitudinal variation in intensity of herbivory is common, but the extent to which it translates into corresponding variation in effects on plant performance is still poorly known. We tested the hypothesis that variation in the fitness-consequences of herbivory mirror differences in intensity of herbivory among three natural populations of the perennial herb Lythrum salicaria along a latitudinal gradient from southern to northernmost Sweden. We documented intensity of herbivory and examined its effect on survival, growth and reproductive output over two years by experimentally removing herbivores with insecticide. The intensity of herbivory and the effects of herbivory on plant fitness were strongest in the southern population, intermediate in the central population and weakest in the northern population. The mean proportion of the leaf area removed ranged from 11% in the southern to 3% in the northern population. Herbivore removal increased plant height 1.5-fold in the southern and 1.2-fold in the central population, the proportion plants flowering 4-fold in the southern and 2-fold in the central population, and seed production per flower 1.6-fold in the southern and 1.2-fold in the central population, but did not affect plant fitness in the northern population. Herbivore removal thus affected the relative fecundity of plants in the three populations: In the control, seed output per plant was 8.6 times higher in the northern population compared to the southern population, whereas after herbivore removal it was 2.5 times higher in the southern population. The results demonstrate that native herbivores may strongly affect the demographic structure of L. salicaria populations and thereby shape geographic patterns of seed production. They further suggest that the strength of herbivore-mediated selection varies among populations and decreases towards the north.     

Pollinator community responses to the spatial population structure of wild plants: A pan-European approach

Land-use changes can alter the spatial population structure of plant species, which may in turn affect the attractiveness of flower aggregations to different groups of pollinators at different spatial scales. To assess how pollinators respond to spatial heterogeneity of plant distributions and whether honeybees affect visitation by other pollinators we used an extensive data set comprising ten plant species and their flower visitors from five European countries. In particular we tested the hypothesis that the composition of the flower visitor community in terms of visitation frequencies by different pollinator groups were affected by the spatial plant population structure, viz. area and density measures, at a within-population (‘patch’) and among-population (‘population’) scale. We found that patch area and population density were the spatial variables that best explained the variation in visitation frequencies within the pollinator community. Honeybees had higher visitation frequencies in larger patches, while bumblebees and hoverflies had higher visitation frequencies in sparser populations. Solitary bees had higher visitation frequencies in sparser populations and smaller patches. We also tested the hypothesis that honeybees affect the composition of the pollinator community by altering the visitation frequencies of other groups of pollinators. There was a positive relationship between visitation frequencies of honeybees and bumblebees, while the relationship with hoverflies and solitary bees varied (positive, negative and no relationship) depending on the plant species under study. The overall conclusion is that the spatial structure of plant populations affects different groups of pollinators in contrasting ways at both the local (‘patch’) and the larger (‘population’) scales and, that honeybees affect the flower visitation by other pollinator groups in various ways, depending on the plant species under study. These contrasting responses emphasize the need to investigate the entire pollinator community when the effects of landscape change on plant–pollinator interactions are studied.     

Plant population size and isolation affect herbivory of <Emphasis Type="Italic">Silene latifolia</Emphasis> by the specialist herbivore <Emphasis Type="Italic">Hadena bicruris</Emphasis> and parasitism of the herbivore by parasitoids

Habitat fragmentation can affect levels of herbivory in plant populations if plants and herbivores are differentially affected by fragmentation. Moreover, if herbivores are top–down controlled by predators or parasitoids, herbivory may also be affected by differential effects of fragmentation on herbivores and their natural enemies. We used natural Silene latifolia populations to examine the effects of plant population size and isolation on the level of herbivory by the seed predating noctuid Hadena bicruris and the rate of parasitism of the herbivore by its parasitoids. In addition, we examined oviposition rate, herbivory and parasitism in differently sized experimental populations. In natural populations, the level of herbivory increased and the rate of parasitism decreased with decreasing plant population size and increasing degree of isolation. The number of parasitoid species also declined with decreasing plant population size. In the experimental populations, the level of herbivory was also higher in smaller populations, in accordance with higher oviposition rates, but was not accompanied by lower rates of parasitism. Similarly, oviposition rate and herbivory, but not parasitism rate, increased near the edges of populations. These results suggests that in this system with the well dispersing herbivore H. bicruris, habitat fragmentation increases herbivory of the plant through a behavioural response of the moth that leads to higher oviposition rates in fragmented populations with a reduced population size, increased isolation and higher edge-to-interior ratio. Although the rate of parasitism and the number of parasitoid species declined with decreasing population size in the natural populations, we argue that in this system it is unlikely that this decline made a major contribution to increased herbivory.     

Pollinator diversity affects plant reproduction and recruitment: the tradeoffs of generalization

One outstanding and unsolved challenge in ecology and conservation biology is to understand how pollinator diversity affects plant performance. Here, we provide evidence of the functional role of pollination diversity in a plant species, Erysimum mediohispanicum (Brassicaceae). Pollinator abundance, richness and diversity as well as plant reproduction and recruitment were determined in eight plant populations. We found that E. mediohispanicum was generalized both at the regional and local (population) scale, since its flowers were visited by more than 100 species of insects with very different morphology, size and behaviour. However, populations differed in the degree of generalization. Generalization correlated with pollinator abundance and plant population size, but not with habitat, ungulate damage intensity, altitude or spatial location. More importantly, the degree of generalization had significant consequences for plant reproduction and recruitment. Plants from populations with intermediate generalization produced more seeds than plants from populations with low or high degrees of generalization. These differences were not the result of differences in number of flowers produced per plant. In addition, seedling emergence in a common garden was highest in plants from populations with intermediate degree of generalization. This outcome suggests the existence of an optimal level of generalizations even for generalized plant species.     

Habitat protection,cattle grazing and density‐dependent reproduction in a desert tree

Anthropogenic activities usually trigger changes in the population density of plants. Thus, land management practices can influence density‐dependent demographic parameters and species interactions. We investigated plant‐pollinator interactions and reproduction in Prosopis flexuosa, the largest tree species in the Central Monte desert of Argentina, an important economic and cultural resource for humans and a functionally prominent species. We hypothesized that reproductive output of P. flexuosa would be limited at low densities, and that exclusion of catle grazing would enhance population density and consequently interaction frequency with pollinators and reproductive success. The study was conducted in and around Ñacuñán Biosphere Reserve (Mendoza, Argentina), where cattle grazing has been excluded for over 35 years. Working in five pairs of protected and cattle grazed 1‐ha plots, we recorded density of adult trees, pollinator visitation frequency to inflorescences and seeds per inflorescence in focal trees. Adult tree density was higher in protected plots than in cattle grazed plots. Density of reproductive trees was positively correlated with seed production, suggesting positive density dependence for reproduction (Allee effect). Pollinator visitation to inflorescences and seed production was higher in protected plots compared with plots under cattle grazing. Suppression of anthropogenic degradation has resulted in higher adult tree density in protected plots, indirectly higher pollinator visitation to inflorescences and higher reproductive success of trees. Increased frequency of plant‐pollinator interactions and tree reproduction suggest success of management practices aimed at protecting P. flexuosa woodlands.     

Demographic variation and conservation of the narrow endemic plant Ranunculus weyleri

Ranunculus weyleri is a narrow endemic protected plant from Majorca Island. It is known from only five populations located in two mountain areas 48 km apart. Using demographic data collected from 2007 to 2010, we assessed the demographic status of two populations – font des Coloms (FC) and talaia Moreia (TM) – using Integral Projection Models (IPMs). We showed that none of the two populations were declining under a deterministic model. Population FC was stable (λ = 1.026, CI_95% = 0.965–1.093), while population TM showed sign of demographic expansion (λ = 1.113, CI_95% = 1.032–1.219). Plant survival, flowering probability and the mean number of seedlings per floral peduncle were lower in TM, whereas growth and the number of floral peduncles per reproductive plant were lower in FC. Elasticity analyses showed that management strategies increasing plant survival and growth would be the most efficient to increase λ for both populations. Herbivory pressure by goats has been shown to be high in TM, resulting in high predation rate on floral peduncles. Controlling goat pressure may thus represent a promising management option, provided that we can demonstrate a negative impact of herbivory by goats on survival and growth which are the most critical parts of the life cycle in this species. Meanwhile, initiating a long-term monitoring is of crucial importance to get more insights into the relationships between environmental variation, plant performance and population dynamics.