Patterns of Solidago altissima ramet growth and mortality: the role of below-ground ramet connections

Summary For the rhizomatous perennial, Solidago altissima, I identified clonal fragments in the field, mapped ramet spatial locations, and documented patterns of ramet recruitment, growth, and mortality. Parent ramet size influenced the size and number of daughter ramets produced, and small ramets had lower survivorship and fecundity than large ramets. Similarly, small rhizomes tended to develop into small ramets, and ramets that survived to produce daughter ramets had longer parent-daughter rhizome connections than ramets that did not survive. In addition, most ramets that died during the growing season were connected to (genetically identical) ramets that persisted. There were large size inequalities among rhizomes, ramets, and clonal fragments. Inequalities in the size of ramets increased during the early part of the growing season, then decreased at the end of the season; similar patterns were observed for the growth of clonal fragments. In both instances, the decrease in size inequality could be attributed to the mortality of small individuals (ramets or clonal fragments). I found little evidence that ramet size hierarchies were structured by intraspecific competition. For example, path analyses and randomization tests indicated that size variation among S. altissima ramets was influenced little by the size of their near neighbors (but was influenced by parent size and rhizome size). In addition, within-season variation for the relative size and growth rate of individual ramets led to poor correlations between early and final ramet size; this result suggests that there was no stable hierarchy of dominant and suppressed ramets. I discuss implications of my results for contrasting interpretations of clonal plant population dynamics.     

Daylength and development in four species of Ceramiaceae (Rhodophyta)

Developmental patterns in four species of Ceramiaceae were determined using excised thallus apices grown under a range of light periods. Models of thallus development and organization based on these patterns are presented. Increased rates of apical cell division, greater growth of apical fragments and increased average cell size were found with increasing number of hours light per day between 8–16 and 16–8 h. No aspect of growth investigated was associated with photoperiodic phenomena, and growth occuring during the light break (8-7.5-1-7.5 h) was intermediate between that in 8–16 and 12–12 h. Three patterns of cell elongation were found in the four species in which (1) cell age, (2) cell age and position and (3) cell age, cell position and light period determined cell length at different axial cell positions. Elongation was followed within cells, along axes ofAntithamnion spirographidis for plants grown under different day lengths. Three regions of development were found along main axes: (1) an apical region in which basipetal expansion was greater than acropetal expansion. (2) a zone of stability with equal elongation in apical and basal growth region of cells, and (3) a basal region with greater acropetal expansion. With increasing daylength, the zone of stability was extended to greater ranges of cell length.     

Water integration patterns in two rhizomatous dune perennials of different clonal fragment size

In clonal plants, a clonal fragment is a basic unit. There may exist clonal integration that is often regarded adaptive. By definition, a larger clonal fragment comprises more interconnected ramets and/or occupies a larger area of the habitat. When the habitat is so heterogeneous in terms of essential resources that the resources the whole clonal fragment needs can be captured only in a limited number of microhabitats, a large clonal fragment may require extensive and/or intensive clonal integration. Therefore, we hypothesize that in an environment where the resources are distributed in a highly heterogeneous way, a species forming large clonal fragments possesses more extensive and/or intensive clonal integration gaining essential resources than that forming small ones.This hypothesis was tested in a field experiment with two rhizomatous species growing in inland-dune habitats with high heterogeneity of water resource, one (Psammochloa villosa) forming large clonal fragments and the other (Hedysarum laeve) forming small ones. In P. villosa, tracer-(water-soluble acid fuchsin)-labeled water could be transported along the rhizome at a velocity of about 0.93 m per hour and 4 ramets per hour, which was much faster than that in H. laeve. Similarly, the acid fuchsin-labeled water was transported to a longer length in the rhizomes (3.96 m vs. 1.12 m) and to more ramets (14 vs. 3) in P. villosa than in H. laeve. In P. villosa, the acid fuchsin-labeled water reached the ends of the rhizomes and all ramets along the rhizomes were dyed purple. In H. laeve, however, the acid fuchsin-labeled water could not reach the rhizome tips and along the rhizomes only some ramets were labeled. The results suggest that P. villosa is an extensive and intensive integrator, whereas H. laeve is a restrictive and less intensive integrator, supporting the hypothesis. The possible mechanisms and the ecological implications of the findings were discussed.     

Differential effects of clonal integration on performance in the stoloniferous herb Duchesnea indica, as growing at two sites with different altitude

Clonal integration may be adaptive and enhance the genet performance of clonal plants. Degree of clonal integration may differ between different environments . Here, a container experiment was used to determine how clonal integration affected the performance of the stoloniferous herb Duchesnea indica at two sites with different altitude along the transitional zone between the Qinghai-Tibet plateau and the Sichuan basin of Southwest China. In the experiment, the stolon between partially shaded two ramets experienced severing and intact treatments.We predicted that clonal integration would increase performance of whole clonal fragments and their shaded clonal parts at both sites. In both arctic and alpine environments, clonal plants may form highly integrated plant units (group of ramets).We predicted again that the reduction due to stolon severing in performance of whole clonal fragments and their shaded clonal parts would be greater at the site with high altitude than one with low altitude. The results indicated that the benefit for the shaded clonal parts and whole clonal fragments due to clonal integration was only observed at the site with high altitude. The results suggest that the performance of Duchesnea indica tends to be more responsive to the stolon severing at the site with high altitude than one with low altitude and support the second prediction. In addition, the effects of conditions of the sites and clonal integration on local morphological traits of ramets may be adaptive, five morphological traits of ramet-level (length of petiole, mean stolon internode length, specific petiole weight, specific stolon internode weight and specific leaf area) were investigated. Altogether, the results suggest that clonal integration might help D. indica plants to successfully inhabit the high-altitude habitat of the Qinghai-Tibet plateau of Southwest China, providing new evidences for the notion that clonal integration is an adaptive trait in stressful environments.     

Long-term suppression of insect herbivores increases the production and growth of Solidago altissima rhizomes

Summary Although insect herbivores have many well documented effects on plant performance, there are few studies that assess the impact of above-ground herbivory on below-ground plant growth. For a seven year period in which no large-scale herbivore outbreaks occurred, a broad spectrum insecticide was utilized to suppress herbivorous insects in a natural community dominated by Solidago altissima. Ramet heights, rhizome lengths, rhizome biomass, and the number of daughter rhizomes all were lower in the control plots than in the insecticidetreated plots. These effects should lead to a decrease in the fitness of genets in the control plots relative to the fitness of genets in the insecticide-treated plots. We also found that ramets in the control plots appear to have compensated for herbivory: the ratio of rhizome length to rhizome biomass was greatest in the control plots, which indicates that clones moved farther per unit biomass in these plots than in the insecticide-treated plots. Clonal growth models show that this shift in allocation patterns greatly reduced the magnitude of treatment differences in long-term clonal displacements.Previous work has shown, and this study verified, that clonal growth in S. altissima is well represented by random-walk and diffusion models. Therefore, we used these models to examine possible treatment differences in rates of clonal expansion. Although rhizome lengths were greater in the insecticide-treated plots, results from the models suggest that our treatments had little impact on the short- and long-term displacement of S. altissima ramets from a point of origin. This occurred because S. altissima ramets backtrack often, and thus, treatment differences in net displacements are less pronounced than treatment differences in rhizome lengths.     

Intersexual differences in phenology and damage by herbivores and pathogens in dioecious Rubus chamaemorus L.

Summary Shoot development and damage by herbivores and pathogens to male, female and non-floral ramets of the dioecious, perennial herb Rubus chamaemorus were studied in the field during three consecutive years. Leaves on male ramets were usually consumed more by herbivores and attacked more by fungi than were leaves on female ramets. Male ramets unfolded their leaves later than did female ramets. In 1983, when the level of herbivory was comparatively high, ramets that were fully developed in early June were more damaged by herbivores than were ramets that unfolded their leaves later. Non-floral ramets usually showed intermediate levels of damage compared to male and female flowering ramets.Defoliation caused a greater increase in ramet mortality among females than among males in a field experiment. It is suggested that the different reproductive roles of males and females differently constrain the evolution of defense against herbivores and pathogens in dioecious plants. This may result in intersexual differences both in palatability to herbivores and susceptibility to pathogens.     

Morphological responses to nutrient availability in four clonal herbs

This paper examines morphological plasticity of clonal plants of contrasting habitats and of contrasting architectures in response to nutrient supply. The hypotheses were tested that plants from rich habitats possess greater plasticity in response to variation in resource supply than species from poor habitats, and that rhizomatous species are less plastic in their response than stoloniferous species. Two sympodial rhizomatous herbs (Carex flacca, C. hirta) and two monopodial stoloniferous herbs (Trifolium fragiferum, T. repens) were subjected to four levels of nutrient supply in a garden experiment. One of the two species of each genus (C. hirta, T. repens) is from fertile and the other from infertile habitats. We measured 1) whole plant characters: total plant dry weight, number of modules (product of a single apical meristem) and number of ramets; 2) ramet characters: ramet leaf area and ramet height; and 3) spacer characters: branches per module, length per module and length per module internode.All measured characters in the Trifolium species significantly responded to treatment: the values for all measured characters increased with higher levels of fertilization. The differences in plant characters between fertilization levels were larger in Trifolium repens than in T. fragiferum in terms of whole plant characters, ramet characters and stolon internode length. The two Carex species did not differ in their responses to treatment in terms of most characters measured. In ramet characters and in some whole plant characters the species from fertile habitats were more plastic than those from infertile habitats. In spacer characters this pattern was not found. Foraging could not be demonstrated unequivocally.Morphological plasticity in the stoloniferous (Trifolium) species was much larger than in the rhizomatous (Carex) species. This seems in accordance with a foremost storage function of rhizomes, as against a foremost explorative function of stolons.     

Effects of moisture availability on clonal growth in bamboo Pleioblastus maculata

The effects of moisture availability on clonal growth and biomass investment in the bamboo Pleioblastus maculata were investigated over a four-year period by transplanting Pleioblastus maculata clones into soils with different levels of moisture availability in the field. The results showed that: (1) The higher the moisture availability, the greater the total biomass of P. maculata clones. Although fewer culms are produced at the higher moisture levels, mean tiller biomass is greater. (2) Under different levels of moisture availability, obvious differences in the total rhizome length (p < 0.01), spacer length (p < 0.05) and the sizes of bamboo culms (height, p < 0.01; diameter, p < 0.01) were observed. Thus, the higher the moisture availability, the shorter the rhizomes and the larger ramets. (3) In microhabitats with low moisture availability, bamboo allocated more biomass to underground organs, which promotes elongation of rhizomes and increases root production, thereby helping to capture underground resources essential to growth. In microhabitats of high moisture availability, the biomass is primarily allocated to the aboveground growth of ramets. (4) We suggest that soil moisture availability effects the foraging strategies of bamboo, that bamboo plants growing with low moisture availability produce longer rhizomes (that is, more, although shorter, spacers) with more biomass allocation than plants in high moisture and have a better ability to forage to increase the probability of locating adequate moisture patches. Also, longer length distance between shoots (that is, longer spacers) in high soil moisture than in low is adapted to avoid intense competition from faster growing aboveground growth in high moisture patches.     

Sexual dimorphism in clonal growth forms and ramet distribution patterns in <Emphasis Type="Italic">Rumex acetosella</Emphasis> (Polygonaceae)

We investigated clonal traits in the dioecious herb Rumex acetosella to characterize sexual dimorphism in clonal forms and to correlate below-ground clonal patterns and above-ground ramet distributions. We recorded creeping root length, branching patterns, ramet and clump (caespitose ramets from the same position on the root) sprouting patterns, and biomass allocations in three females and males. We also estimated the patch size of flowering ramets within a quadrat. No sexual dimorphism was detected in the frequencies of branches and flowering ramets per root length. Male plants allocated proportionally more biomass to below-ground organs. Total root length did not differ between the sexes. Females sprouted more clumps with fewer flowering ramets per root length than males, which sprouted fewer clumps with more flowering ramets, which meant that clump sprouting patterns were phalanx-like in females and guerrilla-like in males. Flowering ramets were aggregately distributed in both females and males and patch sizes were similar between sexes, indicating that the spreader propagations were not found in the guerrilla-like males. We assumed that sexual dimorphism occurred in response to physiological integration for higher reproductive effort in females.     

The transition from vegetative to fertile tissue in Fucus vesiculosus

At various stages of receptacle development, segments of Fucus vesiculosus thallus subtending the fertile tips have been grown in culture. At the times of gamete maturation and gamete shedding a number of both reproductive and vegetative branches are regenerated from the wound callus. This is the only region of the Fucus thallus which has been found capable of regenerating fertile receptacles. The effects of a number of growth regulatory substances were studied. 1-naphthoxyacetic acid stimulated budding but no substance increased the proportion of fertile branches. Extracts prepared from mature receptacles did not induce the regeneration of fertile branches from vegetative thallus, but they markedly inhibited the regeneration of any branches. Subsequent estimations of the growth regulatory substances in the receptacles showed that there was a marked increase in growth inhibitors during gamete development. Growth stimulatory substances were also present but these were masked in crude extracts by the amount of inhibitors.     

Clonal integration enhances survival and performance of Potentilla anserina, suffering from partial sand burial on Ordos plateau, China

On Ordos plateau, a semi-arid, desertified area in China, sand burial is a common stress factor for plants. The extent to which sand burial occurs is heterogeneous and unpredictable in space and in time. Therefore, clonal fragments (i.e., interconnected ramets of a clonal plant) often experience partial sand burial, with some ramets buried in sand while the rest may remain unburied. It was hypothesized that clonal fragments are able to benefit from clonal integration, in case they experience partial sand burial. A pot experiment was conducted with Potentilla anserina, a stoloniferous herb often found on Ordos plateau. We used clonal fragments consisting of four interconnected ramets. In the experiment, the two proximal (older) ramets were unburied while the two distal (younger) ramets were either unburied (control) or buried with a 2, 4 or 6 cm deep layer of sand (burial treatments). The stolon connection between the proximal and the distal ramets was either severed or left intact. Stolon severing dramatically decreased the survival of buried ramets. Stolon severing and sand burial had significant effects on plant performance in terms of biomass production, number of leaves and leaf area. A cost–benefit analysis based on performance measures shows that the proximal ramets supported their connected distal ramets and did not incur any cost from this resource export. These results suggest that clonal integration, which is one of the functionally most important consequences of clonal growth, contributes significantly to our test species' capacity to withstand partial sand burial on Ordos plateau, a semi-arid and desertified area of China.     

Competitive Performance of Nymphoides Peltata (Gmel.) O. Kuntze Growing in Microcosm

Two experiments were conducted to investigate the effects of competition on growth and performance of Nymphoides peltata (Gmel.) O. Kuntze in microcosm. Part of the research on growth and biomass allocation of N. peltata in response to competition had been reported early (Wu, Z. & D. Yu, 2004, Hydrobiologia 527: 241–250). This paper focuses on the morphological variations of N. peltata under competitive pressure. First, competition between N. peltata and Zizania latifolia (Griseb.) Turcz. ex Stapf. was assigned with the densities of N. peltata to Z. latifolia ratios of 4:0, 4:2, 4:4 and 4:8. Water surface coverage, surface area per leaf blade and number of leaves per plant of N. peltata all declined significantly with increasing density of competitor. Similar results were also found for petiole length and density of branching. However, the variations of planting density did not significantly affect the number of ramets per plant and the stolon length of N. peltata. Second, competitions between N. peltata and emerged Z. latifolia, floating-leaved Trapa bispinosa Roxb. and submerged Myriophyllum spicatum L. were also studied simultaneously. The results showed that significant difference was only found for the water surface coverage of N. peltata. No other significant differences were found for the number of ramets per plant, number of leaves per plant, density of branching, surface area per leaf blade, petiole length, and stolon length of N. peltata. Our studies indicate that N. peltata presents morphological variations when it is growing with Z. latifolia, such that the growth of above-ground parts decrease (i.e., leaf number, petiole length, branching density) and the growth of below-ground parts remains stable (i.e., stolons length). However, N. peltata does not show apparent differences in morphology when it is growing with T. bispinosa or M. spicatum. Accordingly, we conclude that the growth of N. peltata may be apparently inhibited by the presence of Z. latifolia, while T. bispinosa and M. spicatum may have little impact on the growth and performance of N. peltata.     

The reproductive biology of Pellonula afzeliusi Johnels,and Sierrathrissa leonensis thys Audenaerde in Lake Kainji,Nigeria

Aspects of the reproductive biology of the two species of clupeids known to occur in Lake Kainji, Pellonula afzeliusi Johnels and Sierrathrissa leonensis Thys Van Den Audenaerde were studied for a period of twenty eight months. Mature individuals were found in both species all the year round but with a prolonged peak of activity from December to May, more distinct in P. afzeliusi than in S. leonensis.There were no significant length differences between mature males and females in both species. The smallest mature individuals were 28 mm standard length female; 27 mm standard length male in P. afzeliusi, while the corresponding figures for S. leonensis were 18 mm standard length female and 19 mm standard length male.No sexual dimorphism was observed. There was a simple correlation between fecundity and fish standard body length as well as weight in both species.     

Influence of light and nitrate assimilation on the growth strategy in clonal weed <Emphasis Type="Italic">Eichhornia crassipes</Emphasis>

We studied as to how the inter-connected modular architecture of clonal Eichhornia crassipes allows nutrient to transfer from established ramets to developing ramets, and nitrate translocation within clonal system and how such a strategy may play an important role in successful establishment and expansion of this clonal plant. Using this stoloniferous E. crassipes as a model, we studied the effects of light and nitrate availability on growth and nitrate assimilation in inter-connected parent and offspring ramets. Our results showed that increase in light and nitrate availability significantly increased growth rate of the whole clonal fragments and reproduction of offspring ramets in E. crassipes. In addition, increases in nitrate reductase (NR) activity and glutamine synthetase (GS) activity were observed in both parent and offspring ramets with increase in light density and nitrate supply. We also found that nitrate translocation is greater in offspring ramets than in parent ramets under abundant light and nitrate environment in this fast-growing clonal plant. Consequently, majority of nitrate assimilation in offspring ramets is beneficial to the growth of whole clonal system, as indicated by a close correlation between nitrate assimilation in offspring ramets and RGR of whole clonal fragments. We strongly contend that nitrate translocation and assimilation within clone system is important for efficient utilization of nitrogen in alien clonal plant E. crassipes during establishment and expansion, and thus for increase in its invasiveness in natural water columns.     

Nutrient addition does not increase the benefits of clonal integration in an invasive plant spreading from open patches into plant communities

• One benefit of clonal integration is that resource translocation between connected ramets enhances the growth of the ramets grown under stressful conditions, but whether such resource translocation reduces the performance of the ramets grown under favourable conditions has not produced consistent results. In this study, we tested the hypothesis that resource translocation to recipient ramets may reduce the performance of donor ramets when resources are limiting but not when resources are abundant.
• We grew Mikania micrantha stolon fragments (each consisting of two ramets, either connected or not connected) under spatially heterogeneous competition conditions such that the developmentally younger, distal ramets were grown in competition with a plant community and the developmentally older, proximal ramets were grown without competition. For half of the stolon fragments, slow‐release fertiliser pellets were applied to both the distal and proximal ramets.
• Under both the low and increased soil nutrient conditions, the biomass, leaf number and stolon length of the distal ramets were higher, and those of the proximal ramets were lower when the stolon internode was intact than when it was severed. For the whole clone, the biomass, leaf number and stolon length did not differ between the two connection treatments. Connection did not change the biomass of the plant communities competing with distal ramets of M. micrantha.
• Although clonal integration may promote the invasion of M. micrantha into plant communities, resource translocation to recipient ramets of M. micrantha will induce a cost to the donor ramets, even when resources are relatively abundant.

     

Physical connection decreases benefits of clonal integration in Alternanthera philoxeroides under three warming scenarios

Physical connection between ramets usually allows clonal plants to perform better but can have the opposite effects in some cases. Clonal integration and the effects of climate warming have been extensively studied, but to date little is known about how climate warming affects the benefits of clonal integration. We conducted a field experiment in which Alternanthera philoxeroides segments with connected and severed stolons were subject to four climate regimes (ambient, day warming, night warming and daily warming), and measured final biomass, number of ramets and total length of stolons. Across the three warming treatments, temperature rise suppressed growth of clonal fragments with connected stolons but increased growth of fragments with severed stolons; temperature rise affected the biomass of distal ramets but not proximal ramets, and had similar effects on the numbers of proximal and distal ramets. When the three warming treatments were considered separately, they had contrasting consequences for the benefits of clonal integration. Specifically, when fragments were exposed to day and night warming, physical connection evened out the advantages of clonal integration that occur under ambient conditions; when fragments were exposed to daily warming, physical connection led to smaller clonal plants. These findings suggest that physical connection between ramets may be disadvantageous to overall performance of A. philoxeroides fragments under climate warming, and also indicate that the net consequences of daily warming outweigh those of day or night warming.     

Effects of the loss of clonal integration on four sedges that differ in ramet aggregation

Although clonal growth is a dominant mode of plant growth in wetlands, the importance of clonal integration, resource sharing among ramets, to individual ramet generations (mother and daughter) and entire clones of coexisting species has not been well investigated. This study evaluated the significance of clonal integration in four sedge species of varying ramet aggregations, from clump-forming species (Clumpers –Carex sterilis, Eleocharis rostellata), with tightly aggregated ramets (rhizomes<1cm), to runner species (Runners –Schoenoplectus acutus, Cladium mariscoides), with loosely aggregated ramets. We manipulated clonal integration by either severing connections between target mother and daughter ramets or leaving connections intact, and then planted them in an intact neighborhood of a fen in Michigan, USA. We measured growth parameters of original and newly produced ramets over two growing seasons and conducted a final biomass harvest, to address four hypotheses. First, we expected integrated clones to accumulate more biomass than severed clones. However, final clone-level biomass and ramet production were the same for both treatments in all species although severing initially stimulated ramet production by Schoenoplectus and produced a more compact ramet aggregation in Cladium. Second, we hypothesized that mother ramets would experience a cost of integration, through reduced ramet or biomass production, while daughters would experience a benefit, through increased resource availability from mothers. Mother ramets of Cladium suffered a cost from integration, while Schoenoplectus mothers suffered a slight cost and Carex daughters saw a slight benefit. Finally, we hypothesized that integration would be more active in runner species than in clumper species. Indeed, we documented more active integration in runners than clumpers, but none of the study species were dependent upon integration for growth or survival once daughter ramets were established with their own roots and shoots. This study demonstrates that integration between established ramets may not be the most important advantage to clonal growth in this wetland field site. The loss of integration elicited varied responses among coexisting species in their natural habitat, somewhat but not completely related to their growth form, suggesting that a combination of plant life history traits contributes to the dependence upon clonal integration among established ramets of clonal species.     

Vegetative propagation by fragmentation of Gelidium sclerophyllum (Gelidiales,Rhodophyta)

Results of the first phase of production of "seed" for a project of marine culture of species of Gelidiales are presented. Vegetative fragments of different sizes and from different parts of the thallus of Gelidium sclerophyllum from the Mexican tropical Pacific coast were cultured under nine treatments with different N and P concentrations. In treatments without N all fragments died; good vegetative growth was present in all remaining treatments. Growth in length and branch production were favored in medial fragments, and rhizoid production was favored in apices. Growth in length and biomass increase were stimulated by high N concentrations (2–3 mM), and branch and rhizoid production were stimulated by high P concentrations (100–150 µM).     

A mutant with constitutive sexual organ development in<Emphasis Type="Italic"> Marchantia polymorpha</Emphasis> L.

In lower land plants, genes controlling the transition from vegetative growth to sexual reproduction have not yet been identified. In the dioecious liverwort Marchantia polymorpha, the transition to sexual reproduction accompanied by the formation of sexual organs on the gametophytic thallus is initiated under long-day conditions. By particle bombardment-mediated mutagenesis, we generated a mutant of M. polymorpha that constitutively forms sexual organs. This mutant is fully fertile, showing that the mutation does not affect formation of male or female sexual organs per se. Genetic analysis reveals that this phenotype is caused by mutation of a single autosomal locus, suggesting that this mutation defines or controls a gene regulating the transition to sexual reproduction in M. polymorpha.     

Recovery of evergreen clonal dwarf shrubVaccinium vitis-idaea after simulated microtine herbivory in a boreal forest

The evergreen dwarf shrub lingonberry (Vaccinium vitis-idaea L.) was subjected to microtine herbivory simulations to investigate its recovery in a boreal forest. Beside the control (A), the study included three levels of herbivory: clipping of half the annual branches from 50% of ramets (B), removal of 50% of ramets (C), and removal of 100% of ramets (D). Density, growth, and fecundity of the ramets were monitored during the study. New ramets emerged rapidly from dormant basal buds at the base of the removed ramets in groups C and D. After three growth seasons, 60–117% and 42–112% of density and biomass, respectively, had been regained in the groups damaged relative to the control, the difference being insignificant between the treated groups apparently because of the small sample size. Survival, fecundity and net growth of ramets were not affected by the treatment. Mean dry weight of annual branches in new ramets was lower in the damaged groups than the control. The recovery of the lingonberry was unexpectedly good. The results suggest that, since natural herbivory seldom is as heavy as in this work, the time between population density peaks of microtine rodents is usually long enough for the lingonberry to recover in boreal ecosystems.