Multiple disturbances accelerate clonal growth in a potentially monodominant bamboo

Organisms capable of rapid clonal growth sometimes monopolize newly freed space and resources. We hypothesize that sequential disturbances might change short-term clonal demography of these organisms in ways that promote formation of monotypic stands. We examined this hypothesis by studying the clonal response of Arundinaria gigantea (giant cane, a bamboo) to windstorm and fire. We studied giant cane growing in both a large tornado-blowdown gap and under forest canopy, in burned and unburned plots, using a split-block design. We measured density of giant cane ramets (culms) and calculated finite rates of increase (lamda) for populations of ramets over three years. Ramet density nearly doubled in stands subjected to both windstorm and fire; the high ramet densities that resulted could inhibit growth in other plants. In comparison, ramet density increased more slowly after windstorm alone, decreased after fire alone, and remained in stasis in controls. We predict that small, sparse stands of giant cane could spread and amalgamate to form dense, monotypic stands (called "canebrakes") that might influence fire return intervals and act as an alternative state to bottomland forest. Other clonal species may similarly form monotypic stands following successive disturbances via rapid clonal growth.     

基于复合节间组分关系的结缕草克隆植株形态可塑性特征分析

结缕草Zoysia japonica克隆植株的基本形态学单元是复合节间。分析复合节间组分关系,可以进一步揭示其形态可塑性的细微特征和资源传输与分配的差异,同时也可以为形态可塑性成因提供合理的生理生态学解释。本文对温室内、外两种环境条件下生长的结缕草克隆植株的复合节间组分进行测定和分析,结果表明：温室内、外植株主匍匐茎的长度和生物量的波动比一级分枝大,缩短节间长度比伸长节间长度稳定,但缩短节间生物量较伸长节间生物量变化幅度大。伸长、缩短节间长度、生物量分别与复合节序数呈二次函数关系。伸长、缩短节间生物量和分株生物量在一个生长季的生长方程亦均呈二次函数关系。主匍匐茎根数量、生物量随复合节数递增基本呈递增趋势。在两种环境下,A分株根数、生物量均大于B分株根数、生物量（在结缕草匍匐茎上,着生于每个复合节的基端和梢端缩短节间上的分株分别称为A、B分株）,且差异明显。温室内植株,在分株发育形成后,伸长、缩短节间的长度、生物量分别与匍匐茎根、A分株根数、B分株根数、生物量间相关性显著,温室外的相关性格局较复杂,且总体显著性低于温室内。结缕草克隆植株基本形态结构单元的复合节上的各个组成部分之间存在的密切相关关系,是导致结缕草克隆植物形成形态可塑性的细微特征格局的主要原因。     

Disturbance by ice and life-history adaptations of the seagrassZostera marina

The formation of winter ice, and its movement with the tides, has had a major influence on the life-history parameters of shallow-water populations of the rhizomatous marine angiosperm eelgrass (Zostera marina) in Nova Scotia, Canada. In this region, and annual form of eelgrass inhabits intertidal and shallow subtidal mudflats and a perennial form is common in subtidal areas. Where lowtide water depth was greater than winter ice thickness (25 cm), ice movement removed much of the aboveground biomass from perennial ramets, but did not influence the density of ramets. Measurements of primary production showed that perennial plants allocated a greater proportion of their total production to below-ground structures than measured in all previous studies on eelgrass. Thus perennials are well anchored in the sediment, are more able to withstand removal by ice, and have reserves available for production of new leaves when ice melts. In the spring, seed germination was greatest in areas where ice had removed whole plants (or their aboveground parts) than among mature ramets which had survived winter intact. Survival of seedlings (new genets) was not affected by shading from the adult canopy, but a shading experiment showed that competition for light with mature ramets had a significant negative effect on morphology, growth and the allocation of seedling biomass to below-ground parts, thus reducing the ability of new genets to survive ice disturbance in the next winter. The annual form ofZ. marina was restricted to areas where low tide water depth was much less than winter ice thickness. Annual plants did not survive winter, had small investment in below-ground parts and high reproductive effort, and overwintered as seeds. The genetic status of the two forms and the restriction of the annual to very shallow water are discussed in the light of previous work on eelgrass     

Size and estimated age of genets in eelgrass, Zostera marina, assessed with microsatellite markers

We examined the spatial distribution of genotypes in a perennial population of eelgrass, Zostera marina L., at two spatial scales. We mapped and sampled 80 ramets in a subtidal area of 20 × 80 m, and an additional 15 ramets in two 1-m² sub-quadrats. Ramets were genotyped for seven polymorphic microsatellite loci. Among a total number of 54 genotypes detected, 12 occurred more than once. The ramets of ten of these genotypes occurred in clusters and represented genets based on their expected multi-locus genotype frequencies. The size distribution of genets was uneven with estimated ramet numbers ranging from 2 to 5000. Whereas some areas displayed a high genet diversity, which may indicate past disturbances, large genets (≥10 m²) predominated in other locations of the sampled plot. Spatial heterogeneity in clone distribution was also obvious at the smaller sampling scale (15 ramets sampled within 1 m²) where the clonal diversity (genets identified/ramets sampled) was 0.24 in one quadrat, and 0.077 in the other. Ramets belonging to the largest clone were maximally 17 m apart, which corresponds to a genet age of 67 yr based on annual rhizome growth rates. We conclude that the spatial arrangement of clones in seagrasses allows inferences about the past demography and the disturbance regime at a given site which may prove useful for coastal zone management of ecologically valuable seagrass meadows. Received: 15 September 1998 / Accepted: 14 November 1998     

黑麦草与入侵杂草紫茎泽兰苗期的相对竞争力

为研究利用黑麦草(Lolium perenne)替代种植治理外来入侵杂草紫茎泽兰(Eupatorium adenophorum)再入侵或新入侵丢荒地,采取复合deWit取代试验设计方法用盆栽植物研究了黑麦草和紫茎泽兰在苗期的相对竞争力,观察在若干密度梯度每密度下不同比例条件下两种植物的相对产量、相对产量总和以及竞争攻击力等参数,并比较其表型特征在不同竞争格局下的异同.黑麦草与紫茎泽兰在所有密度及其比例下的相对产量总和(RYT)均近似于1.0,说明这两种植物面临着对相同资源的直接竞争.竞争的结果是,在所有密度及其比例下,紫茎泽兰混种时的生物量均显著小于单种时的生物量(即相对产量RY小于1.0);而黑麦草的相对产量(RY)变化则恰恰相反.黑麦草的株高和地上生物量并不受混种竞争的显著影响(与单种无显著差异),分蘖数反而高于单种,表现出很强的竞争性;而紫茎泽兰在混种竞争下的株高、分株数和地上生物量均显著低于单种(无竞争),表现出较弱的竞争性.对利用黑麦草替代种植治理紫茎泽兰在机械防治后再入侵以及对丢荒地新入侵问题的可行性进行了讨论.图1表3参18     

Density-mediated, context-dependent consumer-resource interactions between ants and extrafloral nectar plants

Interspecific interactions are often mediated by the interplay between resource supply and consumer density. The supply of a resource and a consumer's density response to it may in turn yield context-dependent use of other resources. Such consumer-resource interactions occur not only for predator-prey and competitive interactions, but for mutualistic ones as well. For example, consumer-resource interactions between ants and extrafloral nectar (EFN) plants are often mutualistic, as EFN resources attract and reward ants which protect plants from herbivory. Yet, ants also commonly exploit floral resources, leading to antagonistic consumer-resource interactions by disrupting pollination and plant reproduction. EFN resources associated with mutualistic ant-plant interactions may also mediate antagonistic ant-flower interactions through the aggregative density response of ants on plants, which could either exacerbate ant-flower interactions or alternatively satiate and distract ants from floral resources. In this study, we examined how EFN resources mediate the density response of ants on senita cacti in the Sonoran Desert and their context-dependent use of floral resources. Removal of EFN resources reduced the aggregative density of ants on plants, both on hourly and daily time scales. Yet, the increased aggregative ant density on plants with EFN resources decreased rather than increased ant use of floral resources, including contacts with and time spent in flowers. Behavioral assays showed no confounding effect of floral deterrents on ant-flower interactions. Thus, ant use of floral resources depends on the supply of EFN resources, which mediates the potential for both mutualistic and antagonistic interactions by increasing the aggregative density of ants protecting plants, while concurrently distracting ants from floral resources. Nevertheless, only certain years and populations of study showed an increase in plant reproduction through herbivore protection or ant distraction from floral resources. Despite pronounced effects of EFN resources mediating the aggregative density of ants on plants and their context-dependent use of floral resources, consumer-resource interactions remained largely commensalistic.     

Population Size and Reproduction in Phlox pilosa

Abstract: We analyzed the relationships between population size and reproductive characteristics in the perennial prairie forb Phlox pilosa , an obligate outcrossing butterfly-pollinated species. We examined 27 populations ranging in size from 9 to over 75,000 flowering ramets in two regions of the state of Iowa (eastcentral and northwest) in 1993 and 1994. We collected flowers from each population and scored them for pollen arrival to stigmas and number of pollen tubes. We collected fruiting ramets from each population at the end of the Phlox growing season and scored them for height, biomass, and reproductive variables, including the number of flowers initiated and opened and the number of capsules initiated and matured. In both years, population size was significantly correlated with the number of capsules matured per ramet. Differences between populations in capsule production were set primarily at the pollination stage. In 1993, pollen arrival to stigmas was significantly lower than in 1994 and was correlated with population size in eastcentral Iowa populations, indicating that lower reproduction in small populations that year was at least partially due to inadequate amounts of pollen being moved. In 1993, weather conditions likely depressed pollinator activity, but absolute capsule formation was high because of high flower production per ramet and high population densities. In 1994, when pollen arrival to stigmas was relatively high and unrelated to population size, outcross pollen movement was greater in larger populations. Increased efficacy of outcross pollen movement in 1994 may have resulted from lower flower production and less dense populations forcing greater pollinator movement between ramets or from variation between years in fine-scale spatial genetic substructuring of populations. Our results indicate that the viability of Phlox pilosa can be best ensured by protecting and creating populations of at least 1000–2000 flowering ramets.     

Evidence that reef-wide patterns of coral bleaching may be the result of the distribution of bleaching-susceptible clones

The hypothesis that intraspecific variation in coral bleaching is a result of the distribution of bleaching-susceptible clonal genotypes (genets) was addressed using photoquadrats recorded during the 1987 Caribbean bleaching event on a reef dominated by Montastraea annularis (Morphotype I), together with manipulative experiments with Porites porites. Nearest-neighbor analysis showed that bleached colonies (ramets) of M. annularis at 10 m depth had a high probability (0.80) of having a nearest bleached neighbor of the same genet rather than a bleached ramet of a different genet. Furthermore, the frequency distributions of bleached ramets of M. annularis in the photoquadrats was significantly different from a Poisson distribution, suggesting that bleached ramets were aggregated on the reef. Manipulative experiments with P. porites from 15 m depth showed that some genets were more susceptible to thermal bleaching than others, since three genets had significantly different rates of zooxanthellae loss when exposed to elevated temperatures in tanks receiving irradiances similar to those found in situ. These results suggest that the in situ patchy distribution of bleached ramets could correspond to the distribution of certain genets, and that adjacent genets can exhibit sufficiently different phenotypes to account for intraspecific variation in bleaching. Further studies of genet-specific coral bleaching may provide valuable insights into the causes and consequences of bleaching.     

水位变化对三峡库区低位狗牙根种群的影响

2009年调查研究了三峡库区长寿段消落带的狗牙根（Cynodon dactylon L．）种群,探讨了库区水位变化对低位狗牙根种群的影响。结果表明,156m处狗牙根地下茎的总茎长、总茎节数和总茎节数／总茎长大于150m处的狗牙根,分别比后者多20．3％、30．1％、11．3％;而其地下茎的总芽数／总茎长、萌芽数和萌芽率分别比后者低7．5％、34．3％、74．9％。同时,156m处狗牙根分株的株数、茎长、叶宽、叶长低于150m处的狗牙根,分别比后者少了26．2％、10．8％、19．0％、37．9％;其茎节数、茎节数／茎长、叶片数、根长较大,分别比后者增加了18．7％、34．2％、10．0％、22．6％。156m处狗牙根植株分株的鲜质量、干质量、鲜质量／总鲜质量、干质量／总干质量分别比150m处的狗牙根低32．5％、13．2％、18．2％和14．2％;其地下茎的鲜质量、干质量、鲜质量／总鲜质量、干质量／总干质量分别比后者高5．8％、17．5％、27．2％、15．2％;且前者的分株、地下茎和根的干鲜质量比均分别比后者高29．6％、12．5％和17．6％。表明,库区水位变化显著促进了150m处狗牙根地下茎茎节伸长、芽形成、芽萌发和分株的生长。因而,低位狗牙根对库区水位变化具有较强的适应能力。     

Influences of season and water depth on the clonal biology of the seagrassThalassia testudinum

Ramet density, leaf relative growth rates, leaf chlorophyll levels, and proximate constituent levels were determined on three dates in 1988 at three water depths for aThalassia testudinum Banks ex Konig meadow in lower Tampa Bay, Florida, USA. Density varied seasonally in patterns unique to each depth. Leaf relative growth rates indicated a unimodal, rather than bimodal, growth pattern at this site. Leaf chlorophyll levels reflected both depth-related and seasonal influences, with levels at all depths increasing in times of high light attenuation. Based on results from leaf relative growth rates and proximate constituent levels, the degree of ramet interdependence appears to vary with sampling date and water depth. The degree of ramet interdependence appears to be maximal in times of genet expansion (June and August) and minimal in times of energy storage (November). Interdependence of ramets varies spatially as well; ramets are maximally integrated in shallow regions (on those dates when genet proliferation occurs), and minimally integrated at deep edges. Depth-related differences in ramet integration are probably due to the spatial heterogeneity of the primary resource limitation varying with water depth, and to depth-related differences in ramet population dynamics. Patterns of ramet physiological integration inT. testudinum are similar to the patterns reported for terrestrial clonal plants.     

Fitness consequences of choosy oviposition for a time-limited butterfly

For the majority of insects, a female's choice of oviposition site(s) greatly influences both the success of individual offspring and her own total fitness. Theory predicts that females most strongly limited by egg number will employ greater oviposition site discrimination than those predominately subject to time limitation. The reproductive success of the butterfly Pieris virginiensis at our Connecticut, USA, field site is strongly time constrained on two fronts. First, during their three-week flight season, only 60% of days and 28% of daytime hours were suitable for flight. Second, larval survival is impacted by the rapid senescence of their spring ephemeral host plant Dentaria diphylla, with eggs laid during the first half of the flight season having approximately three times the survival chance of those laid later. Yet, on average, females choose to oviposit on only half the plants they closely inspect and fly over most ramets without any inspection. Our experiments demonstrate that the preferred host ramets confer an approximate two-fold survival advantage. Females are not choosing plants that senesce later, despite the advantage that such plants would confer. We use empirical data on female behavior and larval performance to parameterize a simulation model. Model results suggest that, despite the notable time limitation in this system, the observed level of female oviposition site preference not only increases individual larval survival, but also total female fitness. Low egg loads in this species may contribute to selection for strong host plant discrimination.     

Disappearing plants: why they hide and how they return

Prolonged dormancy is a life-history stage in which mature plants fail to resprout for one or more growing seasons and instead remain alive belowground. Prolonged dormancy is relatively common, but the proximate causes and consequences of this intriguing strategy have remained elusive. In this study we tested whether stored resources are associated with remaining belowground, and investigated the resource costs of remaining belowground during the growing season. We measured stored resources at the beginning and end of the growing season in Astragalus scaphoides, an herbaceous perennial in southwest Montana, USA. At the beginning of the growing season, dormant plants had lower concentrations of stored mobile carbon (nonstructural carbohydrates, NSC) than did emergent plants. Surprisingly, during the growing season, dormant plants gained as much NSC as photosynthetically active plants, an increase most likely due to remobilization of structural carbon. Thus, low levels of stored NSC were associated with remaining belowground, and remobilization of structural carbon may allow for dormant plants to emerge in later seasons. The dynamics of NSC in relation to dormancy highlights the ability of plants to change their own resource status somewhat independently of resource assimilation, as well as the importance of considering stored resources in understanding plant responses to the environment.     

Differential tree and shrub production in response to fertilization and disturbance by coastal river otters in Alaska

We explored the interacting effects of marine-derived nutrient fertilization and physical disturbance introduced by coastal river otters (Lontra canadensis) on the production and nutrient status of pristine shrub and tree communities in Prince William Sound, Alaska, USA. We compared production of trees and shrubs between latrines and non-latrines, while accounting for otter site selection, by sampling areas on and off sites. Nitrogen stable isotope analysis (delta15N) indicated that dominant tree and shrub species assimilated the marine-derived N excreted by otters. In association with this uptake, tree production increased, but shrub density and nonwoody aboveground shrub production decreased. The reduced shrub production was caused by destruction of ramets, especially blueberry (Vaccinium spp.), through physical disturbance by river otters. False azalea (Menziesia ferruginea) ramets were less sensitive to otter disturbance. Although surviving individual blueberry ramets showed a tendency for increased production per plant, false azalea allocated excess N to storage in leaves rather than growth. We found that plant responses to animal activity vary among species and levels of biological organization (leaf, plant, ecosystem). Such differences should be accounted for when assessing the influence of river otters on the carbon budget of Alaskan coastal forests at the landscape scale.     

Pulses of dead periodical cicadas increase herbivory of American bellflowers

Resource pulses can have both direct bottom-up and indirect top-down effects on their consumers, but comparatively few studies have investigated the top-down effects of naturally occurring resource pulses on plants. This study describes two years of field experiments conducted to determine the indirect effects of 17-year periodical cicadas (Magicicada spp.) on herbivory in American bellflowers (Campanulastrum americanum). In 2004, the area of damaged leaves on cicada-supplemented plants was 78% greater than the area of damaged leaves on control plants. In 2005, cicada-supplemented plants were more likely to experience herbivory by mammalian herbivores than control plants. When large herbivores were excluded, similar patterns of leaf herbivory were observed, but these differences were not statistically significant. These results suggest that the pulsed input of dead periodical cicada bodies increased rates of herbivory on bellflowers, and that this effect was largely mediated by the selective foraging of large mammalian herbivores. More broadly, this study suggests that pulses of limiting resources can have both positive direct effects on plants and negative indirect effects due to selective herbivory, and that the net effects of pulsed resources on plants may depend on the composition and behavior of the surrounding herbivore community.     

九寨沟自然保护区4种水深梯度下芦苇分株地上生物量的分配与生长

芦苇是世界自然遗产--九寨沟自然保护区的一种重要的湿地植物.本文对该地区芦苇海4个不同水深梯度下芦苇的无性系地上分株的生物量分配、生长与繁殖策略进行了比较研究.结果表明,在47 cm (水在土层表面上)水深环境中,芦苇单株的平均生物量(4.2 g)最大.在-15 cm (水在土层表面下15 cm)的生境中,叶生物量百分比(叶生物量占单株总生物量的百分比, 46.1%)最大.芦苇地上分株高度、地上分株有分枝的单株百分比(茎上有分枝的分株占样地总分株的百分数)也存在明显的差别.茎的生物量分配百分比和生长速率随水深的增加而增加.在滩地生境中,开花率、花序的生物量百分比明显大于水较深的生境.分株株高与分株生物量、茎生物量与叶生物量都表现出较明显的幂指数异速生长规律.在-15 cm水深的生境中,叶生物量的生长快于茎的增长;在其他水深梯度的生境中,则是茎生物量的增加快于叶生物量的增加.     

克隆整合提高了入侵植物空心莲子草对北美车前的竞争力

选取北美车前Plantago virginica L.为竞争背景草,以空心莲子草Alternanthera philoxeroides（Mart.）Griseb.为研究对象,通过切断或保持其先端分株与后端分株间的匍匐茎连接,研究了克隆整合对先端分株生长以及竞争力的影响。结果显示：不管是否存在竞争,克隆整合显著提高了空心莲子草先端分株的生物量、总匍匐茎长度、叶片数目和分株数目,并降低了其对茎的生物量投资。此外,克隆整合显著提高了空心莲子草先端分株对北美车前的竞争力。种间竞争显著降低了空心莲子草的生长,但并没有显著影响其生物量分配。上述结果表明,克隆整合在一定程度上能够促进入侵克隆植物的生长和竞争力,从而可能潜在影响其入侵性。     

Ecological Survey of Coastal I Water Adjacent to Nuclear Power I Plants in Taiwan

A total of six nuclear reactors installed in three power plants, two along the northern and one along the southern coasts of Taiwan, started their operations one after another since October 1977. Owing to the large quantities of cooling water intake into and discharge from the plants, some environmental factors such as water temperature, chlorine, environmental radioactivity and nearshore currents may be significantly changed. Variations of these abiotic environmental factors may influence the biological activities in the ecosystem, particularly doing some kinds of damage to marine biological resources. Therefore, the possible environmental impact upon the biological systems including the fishery resources along the northern and southern coasts of Taiwan should be studied before and during the plant operation.

We have started the long-term programmes of biological, chemical and hydro-graphical surveys of the nuclear power plant sites on both northern (since July 1974) and southern (since July 1979) coasts of Taiwan. the survey items include ocean currents, physical and chemical properties of sea water, primary productivity, specific compositions and interspecific relationships among phyto- and zooplankton, algae, invertebrates, corals, and fishes; and radionuclides in water and biological specimens, and fishery statistics. in general, except for a few events, the operations of the six units of nuclear power plants have not produced detectable effects on the marine ecosystem. Radio activity levels and radionuclides in water and the biological specimens remained the same as background levels throughout the survey period. However, the events of coral bleaching and fish body anomalies caused by thermal discharges were observed respectively along the outlets of third and second Nuclear Power Plants. the purposes of this paper are to report and evaluate these two events during the operations of nuclear power plants in Taiwan.     

Ecological Survey of Coastal I Water Adjacent to Nuclear Power I Plants in Taiwan

A total of six nuclear reactors installed in three power plants, two along the northern and one along the southern coasts of Taiwan, started their operations one after another since October 1977. Owing to the large quantities of cooling water intake into and discharge from the plants, some environmental factors such as water temperature, chlorine, environmental radioactivity and nearshore currents may be significantly changed. Variations of these abiotic environmental factors may influence the biological activities in the ecosystem, particularly doing some kinds of damage to marine biological resources. Therefore, the possible environmental impact upon the biological systems including the fishery resources along the northern and southern coasts of Taiwan should be studied before and during the plant operation.

We have started the long-term programmes of biological, chemical and hydro-graphical surveys of the nuclear power plant sites on both northern (since July 1974) and southern (since July 1979) coasts of Taiwan. the survey items include ocean currents, physical and chemical properties of sea water, primary productivity, specific compositions and interspecific relationships among phyto- and zooplankton, algae, invertebrates, corals, and fishes; and radionuclides in water and biological specimens, and fishery statistics. in general, except for a few events, the operations of the six units of nuclear power plants have not produced detectable effects on the marine ecosystem. Radio activity levels and radionuclides in water and the biological specimens remained the same as background levels throughout the survey period. However, the events of coral bleaching and fish body anomalies caused by thermal discharges were observed respectively along the outlets of third and second Nuclear Power Plants. the purposes of this paper are to report and evaluate these two events during the operations of nuclear power plants in Taiwan.     

Mother really knows best: host choice of adult phytophagous insect females reflects a within-host variation in suitability as larval food

Non-random distribution patterns of specialized phytophagous insects on their hosts may depend on intraspecific differences in plant tissue quality, including nutrients and secondary compounds. Secondary compounds are involved in plant resistance, but are also important for the recognition and acceptability of plants as resources by specialized insects. If individuals within a plant species vary in their content of such secondary substances, there may also be qualitative differences between them. In such cases, natural selection will favor insects with the ability to distinguish and prefer the more suitable plants. In Sweden, the leaf beetle Gonioctena linnaeana Schrank (Coleoptera, Chrysomelidae) is highly specialized on one host, the native willow Salix triandra L (Salicaceae). Field observations reveal that some host plants in a population harbor many feeding larvae, causing severe defoliation, whereas neighboring plants may have few or no feeding larvae. Our hypothesis is that the distribution pattern of G. linnaeana larvae in this population results from qualitative differences between individual host plants in combination with the ability of G. linnaeana females to distinguish between plants that are suitable and not suitable for offspring performance. We examine whether larval survival differs depending on diet and whether the content of secondary chemical compounds explains female preference. Based on the higher survival rate of larvae reared on leaves from preferred hosts, we conclude that G. linnaeana females have evolved a behavior that maximizes offspring performance and thus positively affects female fitness. A chemical survey of the plants indicates that luteolin-7-glucoside and an unidentified flavonoid are important for separating the preferred from the non-preferred plants.     

Living at the Edge: Local versus Positional Factors in the Long‐Term Population Dynamics of an Endangered Orchid

Abstract: Populations at the margin of geographic ranges of distribution have been considered more vulnerable than central ones, but recent reviews have caste doubt on this generalization. We examined the reproductive and demographic performance of a rare Euroasiatic orchid (Cypripedium calceolus) at its southwesterly range limit and compared our findings with those of previous studies of nine central populations at the center of the orchid's range. We sought to test the central‐marginal model and to evaluate factors involved in long‐term performance of forest Eurosiberian species with peripheral populations in southern European mountains. We characterized (structure, temporal fluctuations, herbivory, reproductive success, and recruitment at different habitats) four Pyrenean populations of C. calceolus of different sizes (5–3500 ramets) and monitored three of them for up to 13 years. Two quantitative stochastic models (count data and matrix models) were used to assess population trends and viability and the effect of herbivory. Contrary to expectations, and despite the negative effect of sporadic events of herbivory, the peripheral populations we studied (except the smallest one) performed similarly or better than populations occurring in central part of the species’ range in terms of reproductive success and population growth rates. Landscape changes over the last 50 years suggest that natural reforestation could be involved in the success of this plant at its southern limit. Forest expansion in the mountain regions of southern Europe may provide new opportunities for plants with geographic distributions centered mainly at higher latitudes and give some hope for their recovery in future scenarios dominated by biodiversity loss.