Twenty‐five years of plant community dynamics and invasion in New Zealand tussock grasslands

Understanding how plant communities respond to plant invasions is important both for understanding community structure and for predicting future ecosystem change. In a system undergoing intense plant invasion for 25 years, we investigated patterns of community change at a regional scale. Specifically, we sought to quantify how tussock grassland plant community structure had changed and whether changes were related to increases in plant invasion. Frequency data for all vascular plants were recorded on 124, permanent transects in tussock grasslands across the lower eastern South Island of New Zealand measured three times over a period of 25 years. Multivariate analyses of species richness were used to describe spatial and temporal patterns in the vegetation. Linear mixed‐effects models were used to relate temporal changes in community structure to the level and rate of invasion of three dominant invasive species in the genus Hieracium while accounting for relationships with other biotic and abiotic variables. There was a strong compositional gradient from exotic‐ to native‐dominated plant communities that correlated with increasing elevation. Over the 25 years, small‐scale species richness significantly decreased and then increased again; however, these changes differed in different plant communities. Exotic species frequency consistently increased on some transects and consistently declined on others. Species richness changes were correlated with the level of Hieracium invasion and abiotic factors, although the relationship with Hieracium changed from negative to positive over time. Compositional changes were not related to measured predictors. Our results suggest that observed broad‐scale fluctuations in species richness and community composition dynamics were not driven by Hieracium invasion. Given the relatively minor changes in community composition over time, we conclude that there is no evidence for widespread degradation of these grasslands over the last 25 years. However, because of continuing weed invasion, particularly at lower elevations, impacts may emerge in the longer term.     

Declining plant species richness in the tussock grasslands of Canterbury and Otago, South Island, New Zealand

We studied vegetation change on 142 permanently marked transects spread throughout tussock grasslands of Otago and Canterbury, in areas subject to both pastoral and conservation management. The transects were established between 1982 and 1986 and remeasured between 1993 and 1999, providing a record of vegetation change at each site over an interval varying from 10 to 15 years. Each transect consisted of 50 quadrats, each 0.25m(2), in which the presence of all vascular plant species had been recorded. For each transect, we calculated the change between measurements in the mean number of species recorded per quadrat, and the change in the total number of species recorded per transect. Averaged across all transects, there was a significant decline in species richness between measurements at both the quadrat and transect scales. Small herbs (those less than or equal to2 cm tall, excluding Hieracium species) showed the greatest decline. On average, more than one quarter of the small herb species present in a quadrat at the first measurement had disappeared within 10 years. Larger herbs, ferns, rushes, sedges and grasses (excluding Chionochloa species) also declined significantly in species richness, reflecting declines in the abundance of species in these groups. Woody species richness remained constant, while species in the genera Chionochloa and Hieracium increased significantly in mean quadrat species richness, reflecting increases in the abundance of these species along transects. The rate of decline in mean quadrat species richness was unrelated to changes in the abundance of either Chionochloa or Hieracium species, or to an overall increase in total vegetation cover on transects. The rate of decline in species richness was also unrelated to the level of grazing or burning between measurements. However, the rate of decline in species richness was greater at lower elevation, on schist rock and on yellow-brown and yellow-grey soils. Our results suggest that a major compositional change is occurring in these grasslands at a rate that is independent of local variation in management and independent of the widespread invasion of these grasslands by Hieracium species.     

Studies on a climosequence of soils in tussock grasslands

Nematodes were extracted and identified from tussocks growing on eight soil types (Conroy, Cluden, Tawhiti, Lammerlaw, Carrick, McKerrow, Obelisk, Harihari) from altitudes of 80–1550 m. Most soils were from schist parent material in Otago. Samples from the bottom 5 cm of the leaves and the 0–5‐cm and 8–12‐cm soil strata were analysed separately. Altogether 4455 specimens of nematodes were identified, and the percentage composition in each stratum was calculated. Seventy species were found; only 1 occurred at all sites, 22 were found at only 1 site; 28 occurred in all 3 strata, 18 in only 1 stratum. A strong site factor was noted in species distribution, and there was distinct stratification. Correlation coefficients were calculated for nematode abundance and diversity with altitude, rainfall, and chemical factors (pH, organic C, and soil N); calculations were also made for only six sites by omitting Lammerlaw and Harihari, which did not reflect stages in the climosequence. Considering the six sites, total numbers of nematodes decline with altitude, but numbers of species do not; numbers in 0–5‐cm soil are significantly positively correlated with pH, and negatively with organic C. The correlation with pH is not causal, but reflects a negative association of pH with both precipitation and altitude which tends to obscure relationships between nematodes and environmental factors. Paratylenchus sp. was dominant at the two driest sites; at the next site it was mixed with Macroposthonia, which occurred at the subsequent wetter sites; this distribution apparently reflects the resistant preadult stage of Paratylenchus. Most Dorylai‐moidea had a wide distribution, but Belondiroidea and Mononchoidea showed a preference for the wetter sites. Of the 70 species found, 30 were named and 18 were previously known from New Zealand, 6 appear cosmopolitan in distribution, 2 have Australian relationships, and 1 has Southern Hemisphere relationships.     

Web-invasion and araneophagy by New Zealand and Australian pholcid spiders

Abstract

Pholcus phalangioides, Pholcus ancoralis, and Psilochorus sphaeroides were observed in the field in New Zealand (first species only) and Australia (all three species) to invade the webs of other species. P. phalangioides was observed to feed on spiders in alien webs. Webs of each species were frequently contiguous with webs of other spiders and P. sphaeroides sometimes invaded neighbouring webs in pursuit of insects.     

Ecology of snow tussocks in the mountain grasslands of New Zealand

Summary Most species of the genus Chionochloa are endemic in New Zealand where they dominate extensively in the low-alpine vegetation. The severe environment, low summer temperatures and persistent high winds in particular, allows only slow growth rates, especially at higher altitudes, in these long-lived plants.Flowering in several species is associated with some unusual but adaptive features, of which the combined temperature-daylength control of flowering and non-flowering years may be unique among grasses. Adaptive genetic variants of the most widespread species, C. rigida, exploit a wide altitudinal range. This species is favoured by periodic fires but its tolerance was evolved in the absence of grazing mammals.The serious deterioration of alpine grasslands in the 120 years since European settlement can be attributed largely to the alien domestic and feral animals, and future changes will probably reflect the intensity of their grazing.

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Zusammenfassung Die meisten Arten der Gattung chionochloa sind in Neuseeland endemisch, wo sie extentsiv in der niederalpinen Vegetation dominieren. Die rauhe Umgebung, die niedrigen Sommertemperaturen und besonders die anhaltenden heftigen Winde erlauben nur ein langsames Wachstum bei diesen langlebigen Pflanzen, vor allem in größeren Höhen. Diese Pflanzen zeigen, was die Blüte betrifft, einige ungewöhnliche Anpassungen.Periodische Brände begünstigen die häufigste Art (C.rigida); diese Toleranz wurde aber in der Abwesenheit von Beweidung entwickelt.Die erhebliche Verschlechterung der Alpinen Grasländer in den 120 Jahren seit der Ansiedlung der Europäer kann dem Einfluß der fremden Tiere (Haustieren sowie wilden Tiere) zugeschrieben werden; weitere Änderungen dürften vor allem von der Beweidungsintensität abhängig sein.

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Miss E. L. Hellaby Indigenous Grasslands Research Fellow.     

Breakdown of tussock grass in streams along a gradient of agricultural development in New Zealand

Summary 1. We measured the breakdown rate of tussock grass in 12 New Zealand streams in catchments that provided a gradient of agricultural development. We also examined the microbial and invertebrate communities associated with decomposing tussock litter.
2. Pristine streams in the study had low concentrations of dissolved inorganic nitrogen (<10  μ g L⁻¹) and dissolved reactive phosphate (<3  μ g L⁻¹), whereas streams in the most developed catchments had high concentrations of nitrate (>2500  μ g L⁻¹) and phosphate (35  μ g L⁻¹), as well as greater amounts of suspended sediment and fine sediment covering the streambed.
3. Breakdown rate and microbial respiration were significantly related across the sites, and both were positively related to concentrations of nitrate and phosphate. Fungal biomass, measured as ergosterol, was positively related to microbial respiration and was also higher at sites with higher concentrations of nutrients. Total and shredding invertebrates were most abundant at the sites with high nutrient concentrations, but abundance of shredding invertebrates was not significantly related to breakdown rate. Amphipods were the most common shredding invertebrate at most sites, but probably did not contribute greatly to high rates of breakdown in streams in agricultural catchments.
4. With the exception of one site, nutrients from agricultural development appeared to have larger positive effects on litter breakdown than negative effects from sedimentation. Litter breakdown can serve as a functional measure of ecosystem health in streams, but caution should be exercised when a stress, such as land use, can have both positive (nutrients) and negative (sedimentation) effects.     

Determinants for the successful establishment of exotic ants in New Zealand

Biological invasions can dramatically alter ecosystems. An ability to predict the establishment success for exotic species is important for biosecurity and conservation purposes. I examine the exotic New Zealand ant fauna for characteristics that predict or determine an exotic species’ ability to establish. Quarantine records show interceptions of 66 ant species: 17 of which have established, 43 have failed to establish, whereas nests of another six are periodically observed but have failed to establish permanently (called ‘ephemeral’ establishment). Mean temperature at the highest latitude and interception variables were the only factors significantly different between established, failed or ephemeral groups. Aspects of life history, such as competitive behaviour and morphology, were not different between groups. However, in a stepwise discriminant analysis, small size was a key factor influencing establishment success. Interception rate and climate were also secondarily important. The resulting classification table predicted establishment success with 71% accuracy. Because not all exotic species are represented in quarantine records, a further discriminant model is described without interception data. Though with less accuracy (65%) than the full model, it still correctly predicted the success or failure of four species not used in the previous analysis. Techniques for improving the prediction accuracy are discussed. Predicting which species will establish in a new area appears an achievable goal, which will be a valuable tool for conservation biology.     

Protura in native and exotic forests in the North Island of New Zealand

Abstract

This study provides data on population and community ecology of Protura in native forests and Pinus radiata plantations in New Zealand. Abundance, age structure, sex ratios, biodiversity, and relationship with soil chemistry are discussed. Protura were significantly more abundant in pine plantations in comparison to native forests. Among native forests, Protura were most abundant under Southern beech (Nothofagus solandri). The abundance patterns may reflect the association between Protura and fungal communities in the soil. No correlation was found between soil organic matter, nitrogen, phosphorous, pH, cation exchange capacity, and the density of Protura. Protura assemblage composition was significantly related to forest type. New Zealand endemic species were associated with native forests; species with distribution outside New Zealand dominated in pine plantations. The distribution records within New Zealand were expanded for five species. The Protura fauna of New Zealand was increased to 18 species. Berberentulus capensis, Eosentomon australicum and Australentulus tillyardi are new records for New Zealand fauna.     

Deep soil flipping increases carbon stocks of New Zealand grasslands

Sequestration of soil organic carbon (SOC) has been recognized as an opportunity to off‐set global carbon dioxide (CO₂) emissions. Flipping (full inversion to 1–3 m) is a practice used on New Zealand's South Island West Coast to eliminate water‐logging in highly podzolized sandy soils. Flipping results in burial of SOC formed in surface soil horizons into the subsoil and the transfer of subsoil material low in SOC to the “new” topsoil. The aims of this study were to quantify changes in the storage and stability of SOC over a 20‐year period following flipping of high‐productive pasture grassland. Topsoils (0–30 cm) from sites representing a chronosequence of flipping (3–20 years old) were sampled (2005/07) and re‐sampled (2017) to assess changes in topsoil carbon stocks. Deeper samples (30–150 cm) were also collected (2017) to evaluate the changes in stocks of SOC previously buried by flipping. Density fractionation was used to determine SOC stability in recent and buried topsoils. Total SOC stocks (0–150 cm) increased significantly by 69 ± 15% (179 ± 40 Mg SOC ha^‐1) over 20 years following flipping. Topsoil burial caused a one‐time sequestration of 160 ± 14 Mg SOC ha^‐1 (30–150 cm). The top 0–30 cm accumulated 3.6 Mg SOC ha^‐1 year^‐1. The chronosequence and re‐sampling revealed SOC accumulation rates of 1.2–1.8 Mg SOC ha^‐1 year^‐1 in the new surface soil (0–15 cm) and a SOC deficit of 36 ± 5% after 20 years. Flipped subsoils contained up to 32% labile SOC (compared to <1% in un‐flipped subsoils) thus buried SOC was preserved. This study confirms that burial of SOC and the exposure of SOC depleted subsoil results in an overall increase of SOC stocks of the whole soil profile and long‐term SOC preservation.     

Competition, coexistence, and adaptation amongst rodent invaders to Pacific and New Zealand islands

Variation in skull size was investigated for three species of rats (kiore –Rattus exulans Peale; ship rat –R. rattus L.; Norway rat –R. norvegicus Berkenhout) which were introduced by humans to various islands in New Zealand and other Pacific islands. Data from seventy-one islands and 882 specimens are examined for evidence of the effects of latitude, island size and interspecific competition among rats and the house mouse (Mus musculus L.) on skull size, using multiple regressions. For R. exulans, skull size increases with latitude as predicted by Bergmann's rule, but no such effect occurs for the other two rats. There was a positive relationship between island size and the number of species inhabiting it, and some species combinations were more likely to occur than others. For example, R. exulans and R. norvegicus were more likely to occur together, while R. rattus and R. exulans were rarely sympatric. R. exulans and R. rattus skull size was negatively correlated with the number of other rodents on the same island. R. exulans skull size increased on smaller islands in some island groups, perhaps because increased density and consequent increased intraspecific competition on smaller islands favours increased body size. This effect is more pronounced in tropical islands (Solomon islands), than in subtropical ones (Hawaiian islands) and less so in temperate New Zealand. Collectively the data demonstrate that rapid evolution of body size in predictable directions can follow within 150 years of the introduction of species to new receiving communities.     

Distribution and forage use of exotic bumblebees in South Island, New Zealand

The rapid decline in bumblebee populations within Europe has been linked to habitat loss through agricultural intensification, and a consequential reduction in the availability of preferred forage plants. The successful introduction of four European Bombus species to the South Island of New Zealand from England (in 1885 and 1906) provides an opportunity to determine how important different forage plants (also introduced from the U.K.) are to two severely threatened European bumblebee species (Bombus ruderatus and B. subterraneus). In January 2003 we conducted a survey of bumblebee populations across 70 sites in the central and southern South Island, recording which plant species were being used as pollen and nectar sources for each Bombus species. All four bumblebee species showed a clear preference for plants of European origin. Only B. terrestris, the most polylectic species, was recorded feeding on native plant species. The longer-tongued bumblebees, B. hortorum, B. ruderatus, and B. subterraneus, foraged predominantly on just two plant species; Trifolium pratense for both nectar and pollen, and Echium vulgare for nectar. These plant species are now declining in abundance in the U.K. Our results provide support for the hypothesis that the loss of flower-rich meadows, particularly those containing populations of Fabaceae species with long corollae, is responsible for the decline of bumblebee species across Europe. Comparison with earlier bumblebee surveys suggests that long-tongued bumblebees may also be in decline in New Zealand, particularly B. subterraneus which is now very localised and scarce.     

Effects of agricultural development on processing of tussock leaf litter in high country New Zealand streams

1. We compare the rates and mechanisms of processing of tussock (Chionochloa spp.) leaf litter in six New Zealand streams draining grassland catchments that contrast in the extent to which they have been developed for pasture. 2. Rates of processing, measured as rate of weight loss of leaf packs and rate of leaf softening, were at the slow end of the spectrum for vascular plant processing. Processing was faster at developed sites, mediated mainly through the influence of oxidized nitrogen concentration on microbial activity. 3. Few invertebrate shredders colonized leaf packs and it is unlikely that invertebrates had an appreciable effect on leaf processing in our study streams, which do not effectively retain leaf litter. Very small headwater tributaries appear to retain leaf litter and possess a more abundant shredder community. 4. Measures of leaf processing in our six streams were significantly correlated with Petersen's (1992) RCE score of stream condition. We discuss the potential for using rate of leaf litter processing as a method of bioassessment. 5. Even the most degraded stream in our study is classed as ‘good’ using the RCE inventory system. Human impact in the Taieri River is relatively small compared with the degradation observed in some parts of the world.     

Non-random co-occurrence of native and exotic plant species in Mediterranean grasslands

Invasion by exotic species in Mediterranean grasslands has determined assembly patterns of native and introduced species, knowledge of which provides information on the ecological processes underlying these novel communities. We considered grasslands from Spain and Chile. For each country we considered the whole grassland community and we split species into two subsets: in Chile, species were classified as natives or colonizers (i.e. exotics); in Spain, species were classified as exclusives (present in Spain but not in Chile) or colonizers (Spanish natives and exotics into Chile). We used null models and co-occurrence indices calculated in each country for each one of 15 sites distributed along a precipitation gradient and subjected to similar silvopastoral exploitation. We compared values of species co-occurrence between countries and between species subsets (natives/colonizers in Chile; exclusives/colonizers in Spain) within each country and we characterised them according to climatic variables. We hypothesized that: a) the different coexistence time of the species in both regions should give rise to communities presenting a spatial pattern further from random in Spain than in Chile, b) the co-occurrence patterns in the grasslands are affected by mesoclimatic factors in both regions. The patterns of co-occurrence are similar in Spain and Chile, mostly showing a spatial pattern more segregated than expected by random. The colonizer species are more segregated in Spain than in Chile, possibly determined by the longer residence time of the species in the source area than in the invaded one. The segregation of species in Chile is related to water availability, being species less segregated in habitat with greater water deficit; in Spain no relationship with climatic variables was found. After an invasion process, our results suggest that the possible process of alteration of the original Chilean communities has not prevented the assembly between the native and colonizer species together.     

Bergmanns's size cline in New Zealand marine spray zone spiders (Araneae: Anyphaenidae: Amaurobioides)

Members of the spider genus Amaurobioides are restricted to the spray zone of rocky marine coasts, where they construct and hunt from silk retreats. Collecting for this study shows these spiders to be distributed around the entire New Zealand coast. A Templeton, Crandall, and Sing (TCS) analysis of the ND1 mitochondrial gene places specimens from the North Island and the northern half of the South Island into a group distinct from Amaurobioides maritima O.P.‐Cambridge, 1883, which is restricted to the southern half of the South Island. Females of this northern group exhibit latitude‐ and temperature‐related clines in body length, body mass, and residual index of condition, with larger individuals with greater indices of condition being found at cooler, southern sites. This size cline also appeared in a broader geographical analysis that included Amaurobioides piscator Hogg, 1909 from the sub‐Antarctic Auckland and Campbell Islands. Thirteen ND1 haplotypes are represented in the northern group. Both independent contrast analyses and standard regressions of the mean body lengths and mean masses of these haplotypes, and the mean latitudes and temperatures of the sites where haplotypes were present, document a Bergmann's size cline, and provide evidence for an underlying genetic component. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 78–92.     

The diversity and origin of exotic ants arriving in New Zealand via human-mediated dispersal

The number of exotic ant species being dispersed to new regions by human transportation and the trade pathways responsible for this are poorly understood. In this study, the taxonomic diversity, trade pathways, and origin of exotic ants intercepted at the New Zealand border were examined for the period 1955–2005. Overall, there were a total 4355 interception records, with 115 species from 52 genera. The 10 most frequently intercepted genera, and the 20 most frequently intercepted species contributed > 90% of all records. Many of the species frequently intercepted are regarded as invasive species, and several are established in New Zealand. The most intercepted species was Pheidole megacephala . Despite a relatively low trade relationship, a high proportion (> 64%) of the exotic ants which were intercepted originated from the Pacific region. However, the majority of species intercepted from the Pacific was exotic to the region (71%), or to a lesser extent, wide-ranging Pacific native species. No endemic species from the Pacific were intercepted. The effectiveness of detecting exotic ant species at the New Zealand border ranged from 48–78% for different trade pathways, indicating a number of species remain undetected. Trade routes associated with specific geographical regions represent a major filter for the arrival of exotic ant species. Despite the importance of the Pacific as a frequent pathway, we suggest that the future establishment of exotic ant species in New Zealand is likely to be mitigated by a renewed focus on trade routes with cool temperate regions, particularly Australia.     

Invasion patterns across multiple scales by Hieracium species over 25 years in tussock grasslands of New Zealand's South Island

Studying patterns of species invasions over time at multiple spatial scales may help us to elucidate important factors driving those patterns and how they change according to temporal or spatial resolution. Here we provide a large, long‐term, landscape‐scale study of the invasion of three Hieracium species using a dataset that encompasses vegetation change on 124 transects over 25 years across the lower eastern South Island of New Zealand. We investigated the relationships between key environmental and ecological factors and the invasion trajectories of H. lepidulum, H. pilosella and H. praealtum, at two spatial scales: (i) among‐transect colonization and (ii) within‐transect changes in frequency and per cent cover. Our results show that the colonization and spread of Hieracium species among and within transects reflect (i) the importance of initial environmental and biological conditions, (ii) that our sampling captured different periods of the invasion trajectories of each of the three species, and (iii) the effects of differences in life histories of the three species.     

Grass allometry and estimation of above‐ground biomass in tropical alpine tussock grasslands

The puna/páramo grasslands span across the highest altitudes of the tropical Andes, and their ecosystem dynamics are still poorly understood. In this study we examined the above‐ground biomass and developed species specific and multispecies power‐law allometric equations for four tussock grass species in Peruvian high altitude grasslands, considering maximum height (h_max), elliptical crown area and elliptical basal area. Although these predictors are commonly used among allometric literature, they have not previously been used for estimating puna grassland biomass. Total above‐ground biomass was estimated to be of 6.7 ± 0.2 Mg ha^?1 (3.35 ± 0.1 Mg C ha^?1). All allometric relationships fitted to similar power‐law models, with basal area and crown area as the most influential predictors, although the fit improved when tussock maximum height was included in the model. Multispecies allometries gave better fits than the other species‐specific equations, but the best equation should be used depending on the species composition of the target grassland. These allometric equations provide an useful approach for measuring above‐ground biomass and productivity in high‐altitude Andean grasslands, where destructive sampling can be challenging and difficult because of the remoteness of the area. These equations can be also applicable for establishing above‐ground reference levels before the adoption of carbon compensation mechanisms or grassland management policies, as well as for measuring the impact of land use changes in Andean ecosystems.     

Impacts of fine sediment addition to tussock, pasture, dairy and deer farming streams in New Zealand

1. Increased fine sediment input caused by agricultural development is expected to act as a stressor for stream ecosystems. In a large‐scale field experiment, we added fine river sand to 50‐m reaches of three second‐order streams in each of four categories of catchment development (ungrazed tussock grasslands, grazed pasture, dairying and deer farming) and measured the responses of macroinvertebrates and aquatic moss. 2. Before addition, fine sediment cover differed between land uses, being lowest in tussock (7%), intermediate in pasture (30%) and dairy (47%) and highest in deer streams (88%). Sediment addition increased cover by one land‐use category (e.g. augmented sediment cover in tussock streams was similar to pre‐existing cover in pasture streams), and cover remained high in impact reaches (compared with controls) throughout the 5‐week experiment. Sediment addition did not change concentrations of phosphate, nitrate and ammonium, which were generally highest in dairy streams and lowest in tussock streams. 3. Aquatic mosses (most common in tussock, absent in dairy and deer), invertebrate density (highest in deer, lowest in tussock), taxon richness (highest in pasture, lowest in deer) and diversity (highest in pasture and tussock, lowest in dairy and deer) all differed between land uses. Sediment addition resulted in reductions of moss cover, invertebrate taxon richness and richness of Ephemeroptera, Plecoptera and Trichoptera in impact relative to control reaches. 4. The impact of sediment addition was strongest in pasture streams where pre‐existing sediment cover was moderate and richness and diversity of the invertebrate community highest. However, even in the already sediment‐rich and species‐poor deer streams, density of one common taxon was reduced significantly by sediment addition, and another two were affected in the same way in dairy streams, the second‐most intense land use. 5. Our experiment has disentangled the impact of sediment addition from other concomitant land‐use effects that could not be reliably distinguished in previous research, which has mainly consisted of correlative studies or unrealistically small‐scale experiments.     

Tempo and mode of vegetation dynamics over 50 years in a New Zealand alpine cushion / tussock community

Abstract. Question: What are the tempo and mode of long‐term succession and of demographic processes in an alpine community, especially: tenacity, transition patterns, predictions, growth of individual cushion plants, cyclic succession, spatial patterns? Location: A low‐alpine mixed cushion /turf /snow‐tussock / shrub community in southeastern New Zealand. Methods: The distribution of seven plant cover‐types was recorded at 1024 fixed points in an 8 m × 8 m plot at approximately decade intervals for 50 years. The diameters of eight Donatia novae‐zelandiae cushions were monitored. Results: The process was essentially first‐order Markovian. There was a change in transition frequencies about 1980. The tenacity of the two major cover types — cushion and turf — was high, but that of cushion decreased about 1980 as some of its area was taken over by turf. The original informal prediction of 1955 that the cushion/turf would increase proved to be correct, probably because of paludification of the site. A prediction of 1987 made from observed transitions that cushion would dominate over turf has proved untrue because of a change in the transition probabilities in the 1980s, of unknown cause. There is a ten‐fold range in diameter growth rates among the eight cushions measured, but the mean rate of 5.3 mm.a^‐1 is similar to that reported from other alpine and arctic sites. As cushions aged, turf colonized their centres, and in two cases new cushions colonized into this turf: consistent with cyclic succession. The pattern of transitions was compatible with a general interpretation of cyclic succession, but not definitive. Conclusions: Change is slow in this alpine community, and tenacity high. The change in transition frequencies about 1980, the invasion of individual cushions, and the decrease in spatial autocorrelation all suggest that cushions established on the site as a result of the clearance of woody vegetation after 1400 AD. Paludification may be causing some loss of tussock grass. A tendency for the cushions to break up, and the shallow peat accumulated below them, may indicate that they are the first generation of cushions on the site. Though these cushions are breaking up, other cushions are establishing, and cushions will continue to be an important part of the vegetation dynamics which may be part of a cyclic succession.