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Ecotones have long been a focus of ecological research, and there is considerable current interest in functional traits in community ecology. Yet, surprisingly, the functional trait approach has not been applied to ecotones. A bog-forest sequence in southern New Zealand was sampled with a grid of quadrats, and eight traits related to leaf function were measured on the 54 species found. Two ecotones were identified using moving-window analysis: Ecotone I was the transition from bog to edge forest, and Ecotone II was the transition from edge forest to tall climax forest. No strict ecotonal species were present. In contrast to theoretical predictions, species richness was not higher or lower in either ecotone, rather, both ecotones represented a transition in richness from one community to the other. It has long been said that ecotones are mosaics, but species mosaicity was no higher in either ecotone than in the adjacent communities, in fact it was lower in Ecotone I. Functional trait diversity decreased along the sequence from bog to forest, with no deviation in either ecotone. However, examining mosaicity in terms of traits, there was a steady rise in Ecotone I and, in conformance with ecotone / functional trait theory, a clear peak in Ecotone II. We conclude that the features claimed for ecotones are often not present, and whether they are present is dependent on the components measured: species vs traits. Here, the clearest patterns were seen in trait mosaicity, but even this differed markedly between the two ecotones. Generalisations about ecotones should be avoided; they will vary from ecotone to ecotone, and probably depend on the type of ecotone: anthropogenic, environmental, switch, etc.

Effects of up to 46 yr retirement from grazing Chionochloa spp. rangeland were assessed in exclosure plots on the Old Man Range, Central Otago. Exclosures at 910 and 1220 m have been ungrazed since 1960, one at 1230 m since 1964, and another at 1590 m remained stock-proof from 1960 until the mid 1980s. Burning history varied between sites. Vegetation structure and composition, including invasive Hieracium spp. and topsoil chemistry, were measured in the exclosures and adjacent grazed sites. Retirement had no significant effect on topsoil chemistry but was associated with increased indigenous plant diversity. There was negligible increase in the woody component under long-term protection. Density and cover of Hieracium lepidulum were significantly higher in the ungrazed 910 and 1230 m exclosures, but not in the 1220 m exclosure. Its invasiveness decreased with altitude, probably through frosting of maturing inflorescences. H. pilosella and H. praealtum were common only on a recently burnt, heavily grazed site at 1230 m. Strategic light grazing of these grasslands may facilitate removal of flower heads of H. lepidulum and reduce its invasiveness, but maximizing recovery of snow tussock following burning is recommended to retard establishment and/or spread of H. pilosella and H. praealtum.

Vegetation patterns of subalpine gully-head mires were investigated in the flat-topped Lammerlaw and Lammermoor Ranges, South Island, New Zealand. Two intensively studied mires each consist of a series of peaty terraces and scarps. Terraces may contain pools, elongated downslope in the narrow, lower altitude mire, but across slope in the broader, upper mire. A crest occurs on some terrace lips, and marginal “spillways” (channel-like zones) occur down some scarps. Some mires have drained by subsurface pipes.Vegetation analysis distinguished between grassland or herbfield on gully sides, vegetation of mire margins, showing aspect differences on the steeper, lower mire, and the vegetation of gully floors, including oligotrophic mire centre vegetation and species-poor pools. The crests, though warmer, bore no special vegetation type.Mineral soil beneath the peat indicates a previous non-mire vegetation, which has subsequently paludified. Scarp slumps indicate downslope creep of organic material. Peat fissures, and mineral, vegetation, and erosion dams all appear to have initiated development of some pools.Mires are designated gully-head ribbon fens. Patterning appears to be accentuated because of the mires' gully-head location on broad-topped ranges, and drainage of soligenous water from upslope gully sides. These apparently unique fens give insight into patterning in aapa mires, and merit special conservation.

AbstractSeasonal changes in the semi‐arid grassland vegetation of Central Otago, New Zealand, are examined using data collected in nine pairs of spring and autumn sampling dates at five long‐term plots, and data from consecutive autumn, spring, and summer surveys across an environmental gradient. Seasonal changes are small in relation to those occurring in the vegetation from year to year, and to spatial differences in vegetation across the landscape. Seasonal changes in community characteristics and in the abundance of most species differ between years. Climatic control of seasonal change appears to be complex and site‐specific. Greater seasonal variation, in both species presence and species abundance, is found in shady sites and on deeper soils. Spring vegetation tends to be more variable and less well structured than autumn vegetation. It is suggested that the annual soil moisture cycle of winter recharge and summer depletion leads to a random element in the spring vegetation (i.e., the relatively widespread germination of distributed seed under temporarily favourable climatic conditions) and that, by autumn, species are more strongly confined to particular environments according to their tolerance of moisture stress.

The taxonomy of the genusFumaria has not been considered in detail sincePugsley's work in 1919 ff., and few modern methods have been applied to it. In a phenetic study, 33 populations of 11Fumaria spp. were grown in uniform conditions, and seven morphological characters measured. After re-expression and transformation the data were analysed by cluster analysis and principal components analysis. Alternative analyses did not indicate contradictory taxonomic conclusions. Artificial crosses gave some evidence on interfertility, and suggestedF. occidentalis to be an allopolyploid ofF. bastardii ×F. capreolata.Pugsley's subsectional classification is supported within sect.Parviflora, but not within sect.Grandiflora. His two sections are seen to be meaningful, but not discrete.

Many plant species prominent in the native vegetation of the dry shingle banks at Dungeness (Britain) are also prominent as exotics in the dry Upper Clutha catchment (New Zealand). To examine the realised niche relations of these species, vegetation was sampled in the two areas. Inverse classification and ordination were used to determine the relative beta niches of the species in the two areas. There was little agreement; it seems that the exotic species in the Upper Clutha were pre-adapted to different niches from those in their native range.

Much ecological theory assumes that the number of species that can coexist (by ‘species packing’) is limited, because competitive exclusion occurs when any pair of species within a guild is too similar — ‘species saturation’ or ‘niche limitation’. If such niche limitation occurs, the proportion of species in each guild should be relatively constant — ‘guild proportionality’. This concept is applied to the guilds represented by strata in a forest. A method is produced, and used to examine a New Zealand temperate rain forest. Most strata showed no deviation from a null model of no niche limitation, i.e. no tendency to guild proportionality. The proportion of lianes was more variable than in the null model, tending to be inversely related to the proportion of epiphytes, Canopy tree proportion was significantly more constant than in the null model, but this could be interpreted as a limit caused by the size of a canopy tree individual.

Apparent constancy in the ratio of predator species to prey species has been offered as evidence that ecological communities are structured by interspecific interactions. If significantly different from random expectation, this effect would be one of the few sound pieces of evidence for community structure. The evidence was re-evaluated by using the data from previous studies to form species pools, and forming simulated ‘communities’ by drawing species at random from these pools (with replacement). Using a correlation coefficient (number of predator species versus number of prey species), and also the statistic used by the original workers (where different), the observed predator:prey correlation was compared to that for the random communities. In five studies, the observed predator:prey ratio was not significantly different from random expectation. In the only two studies where there was significant departure from the null model, it was with more variation in the ratio than expected on a random basis. It is concluded that there is as yet no evidence for near-constant predator:prey ratios.

Identification techniques are discussed with particular reference to online keys. These are interactive keys in which a computer program selects successive questions from its database to guide the key‐user through an optimal identification course. Criteria that can be taken into account in selecting the optimum question at each stage include evenness of the split, the number of indeterminate database entries for each question, commonness of the species, and the part of the plant to which questions refer. Allowance can be made for user preferences and mistakes, and for inaccurate database entries. All such information can be accumulated over a number of identification sessions. This enables the program to improve its own performance, and points out sources of difficulty to the compiler of the database.

An area of New Zealand alpine herbfield, 22×22 m, was sampled on a 3×3 m grid.

The vegetation of a dune slack at Mason Bay, Stewart Island, New Zealand was found to comprise a mosaic of communities. Although the broad vegetational patterns could be correlated with the depth of the water table, the patterns were far from simple. Species diversity over the whole slack was lower than values reported from European dune slacks; even the most diverse communities did not reach European mean values.

Roadside vegetation was surveyed across the southern part of the South Island, New Zealand. Samples were taken at 10 km intervals along 750 km of selected roads that provided a climatic gradient from semi-arid to hyperoceanic conditions and which crossed both, areas of farmland, where the native vegetation has been replaced by an anthropogenic plant cover consisting almost entirely of introduced species, and areas of managed native tussock grassland and native forest. Contiguous plots, placed in four zones parallel to the road, were used to examine any lateral differentiation of vegetation.

Plant community structure was investigated in a species-poor grassland on slightly alkaline soil, subjected to eight combinations of seasonal grazing management.

Several mechanisms have been proposed for group selection, to account for the evolution of altruistic traits. One type, Neighbourhood models, suggests that individuals react with those immediately around them, but with no recognition mechanism. The organization of plant populations seems especially favorable for this type of selection. The possibility of Neighbourhood selection was investigated by simulating a plant population. It was possible for an altruistic trait to evolve, though only under restricted conditions. The main requirement was gene flow only by very restricted pollen dispersal, and a high benefit : cost ratio in the altruistic relationship. Under conditions favourable for such evolution, the starting frequency of the allele, the initial pattern, and the population size, had little effect. Inbreeding tended to prevent the increase of the altruism allele, though this depended on the mechanism of selfing. Known ecological features of plants are discussed that could be considered altruistic and hence require some form of group selection for their evolution, and whether the benefit : cost requirements are likely to be met. Neighbourhood models of group selection are a possibility in plant populations, and we therefore cannot exclude the possibility of altruism in plants. However, Neighbourhood selection is weak force, unlikely to be effective in the face of opposing individual selection. It may be more important as reinforcement of individual selection.

Variance deficit in richness is not reliable evidence for niche limitation. The main problem is the effect of limitation to individual plant module packing at small quadrat sizes, though environmental and historical patchiness can also confound the results unless patch models are used. More reliable approaches to community structure (assembly rules) are those that take into account the characters of the species—guild proportionality, texture convergence and limiting similarity test.

The grass, Festuca ovina, was grown in a nutrient-poor medium with three levels of nitrogen (N) fertilization, four of phosphorus (P), and three of potassium (K), in factorial combination. Overall, there were considerable nutrient responses with evidence of toxicity at high levels of all three nutrients. However the nutrients interacted in all possible combinations, such that toxicity effects were seen only when levels of the other nutrients were low. This is the first report of N, P, and K toxicity for a single species, and the first report of N x P x K interactions in macronutrient toxicity. The occurrence of toxicity interactions between all three possible pairs of macronutrients, reported here for the first time from a single species, supports the osmotic theory of macronutrient toxicity.

An undisturbed podocarp-broadleaved rain forest was sampled in eight strata (synusiae): canopy, small tree, shrub, low shrub, herb, ground, epiphyte and liane. Independent classifications of the quadrats were performed using the eight strata, and the classifications were correlated. Relations between strata were significant, but weak. Using records of plants of all ages, the relations largely reflected the presence of seedlings of woody species in the ground and herb strata. Using only records of species present as adults, the relations were quite different, and at least some seemed to reflect sociological interactions. Relations between a tree and a herb stratum was lower than in McCune & Antos' (1981) investigation, probably because of the narrow ecological range of the present study area.

Repeated patterns, of a type that would be expected to result from limitations to species coexistence (i.e. ‘assembly rules’) were sought in the Park Grass experiment. This classical grassland experiment was sampled in two years, using replicated biomass samples. Variance in a number of measures was examined, and compared to the variance expected under appropriate null models, the latter based on assumptions of no interactions between species. In each case, an assembly rule would result in low variance. Examining variance in species richness between quadrats within a treatment, there was no indication of constraint on species co-occurrences; variance in richness was actually greater than expected under the null model, attributable to environmental variation or perhaps positive interactions between species. However, there was control on biomass, evidenced by variance in total biomass (i.e. over all species) within a treatment being significantly lower than expected under the null model. There was no indication of community structure based on guilds (i.e. functional types). Although there was in 1991 some, non-significant, indication of a constant proportion of species from the legume guild, there was no sign of such an effect in 1992. Searches for intrinsic guilds failed to converge. There was no indication at all of constancy in the proportional representation of guilds by biomass. Thus, there is good evidence for competitive control on plant growth, but none for control of species occurrences. There is no convincing evidence for guild structure in this community at the scale sampled. Possible conflict is discussed between the existence of evidence for temporal stability but the absence of evidence for spatial uniformity. It is concluded that most of the mechanisms proposed for temporal stability will not necessarily lead to control on spatial variation. For many mechanisms, this would depend on the spatial scale examined.

There is still disagreement as to whether plant communities can be described as conforming to certain assembly rules. We searched for such rules in the vegetation of four dune slacks in west Wales by examining variance in richness, guild proportionality, biomass constancy and dominance/diversity relations. To test for the occurrence of niche limitation, variance in quadrat species-richness was compared to null models of species occurrence. Using an Overall-model, one site showed a deficit of variance, but this disappeared when a Patch-model analysis was used. It therefore seems likely that the effect observed was due to equality in the species pools adapted to different microenvironments. The proportional representation of functional guilds was examined, in guilds based on morphology and life history. Significant constancy of guild proportions was seen for the annual guild in the only site in which it occurred, perhaps reflecting a regeneration niche. Total biomass per quadrat was examined, and compared to a model in which the biomass of each species was determined at random from the biomasses of that species at the site. Surprisingly, the observed biomasses showed no departure from the null model. However, there was considerable discrepancy from an alternative null model in which biomasses were allocated at random irrespective of species. This would imply that competition limits species coexistence, rather than performance. Examination of the proportions of species from different potential-size classes in each quadrat gave limited confirmation. The local abundance of species (mean biomass) was significantly correlated with the frequency of the species within a site, parallelling the geographical-range/local-abundance correlation previously reported. Five dominance/diversity models were fitted to the biomass data. The best fits were given by the Geometric or the General Lognormal models, though which fitted best varied between and within sites. Between sites, there was some indication of a consistent difference in Preston's ‘gamma’. Most of the results are compatible with Gleason's Individualistic concept of the plant community, though there are several pointers that assembly rules have some impact on community structure.