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Despite the ubiquitous presence of fungal endophytes in woody plants, mechanisms underlying variation in foliar fungal endophyte communities are poorly understood. Given that endophytes in woody plants are predominantly horizontally transmitted, fungal endophyte colonization of foliar tissues is likely to be influenced by plant resistance traits. Here, we evaluated the association between leaf resistance traits and colonization and community composition of horizontally transmitted endophytes (HTE) in 10 dominant trees species in a temperate rainforest in Southern Chile. Because resistance traits might restrict colonization of HTE, it was hypothesized that host trees with similar leaf resistance traits would show similar HTE communities.We measured leaf traits with reported roles in plant resistance against pathogens and/or herbivores: cell wall polysaccharides, leaf toughness, flavonoids, anthocyanins, terpenoids and chitinases. We also determined variation in fungal read counts, number of operational taxonomic units (OTUs), diversity and community structure across tree species. Foliar fungal endophyte communities were characterized using Illumina MiSeq sequencing of tagged amplicons of the ITS1 region.Fungal read counts were significantly different among host trees, while number of OTUs and diversity were similar among them. Multivariate analyses showed that community composition of endophytic fungi significantly differed among hosts, and that variation in cell wall, flavonoids, anthocyanins and terpenoids was associated with differences in HTE communities. We found that host trees sharing leaf resistance traits harbour similar HTE communities. Fungal read counts decreased with increasing content of cell wall polysaccharides, while endophyte diversity decreased with increasing anthocyanin levels. Fungal read counts, in contrast, were positively associated with terpenoids. Additionally, culture‐based data indicated that some HTE strains inhibited the growth of the common fungal pathogen Botrytis cinerea.Synthesis. Overall, we found that leaf resistance traits may influence fungal endophyte colonization and community composition in tree species, likely through deterrent effects of structural and chemical traits. We suggest that endophytic fungi that overcome resistance traits might play a role in plant protection. [ABSTRACT FROM AUTHOR]

Several plant species have the potential to facilitate the presence of other plant species in the community, and yet most of our knowledge on this phenomenon comes from studies considering only one facilitator species. What happens when there are two facilitator species in the community? Are the facilitation effects by one species being altered by the presence of a potentially second facilitator species and vice‐versa (i.e. bidirectional facilitation)?Knowing that cushion plants ameliorate stress and improve soil fertility and that cluster root‐bearing species mobilize soil phosphorus (P), we investigated the potential occurrence of bidirectional facilitation via stress amelioration and nutrient exchange in the cushion plant Acaena integerrima (Rosaceae) and the cluster root‐bearing tree species Embothrium coccineum (Proteaceae).In southern Chile, where both species naturally occur, we compared aspects of the vegetative and reproductive performance of each species growing in association or not. We also determined if Embothrium alters the nurse effects of Acaena cushions on other species by evaluating species richness, frequency, and abundance in cushion plants with and without Embothrium. To infer the existence of nutrient exchange, we determined soil and leaf nutrient levels of both species.Species richness, frequency and abundance were higher within than outside Acaena cushions. Although the presence of Embothrium did not enhance the overall positive effects of Acaena on species composition, nine species occurred more frequently when Embothrium was present. Embothrium occurred more frequently and had a higher survival and leaf nitrogen (N) concentration when growing with Acaena than without it, although its growth and leaf P concentration were lower. In contrast, Acaena had a lower number of and mass of fruits per inflorescence and a higher leaf P concentration when growing with versus growing without Embothrium.Synthesis. The cushion plant Acaena integerrima facilitates the occurrence of many species in the community, including the cluster root‐bearing species Embothrium coccineum, which in turn enhances the facilitation effect of Acaena on certain species. When Embothrium and Acaena occur together, the latter improves its nutritional status but reduces its fitness, implying a lack of bidirectional facilitation. [ABSTRACT FROM AUTHOR]

1. Altitudinal tree line ecotones (ATE) are among the most sensitive plant formations facing global warming as the altitudinal decrease in temperature is considered the driver controlling the upper elevation limit of tree lines world-wide. In this study, we attempted to answer the following questions: (i) how have the conditions during the last 2-3 centuries affected ATE tree growth (physiology) and recruitment (demography)? and (ii) how strong is synchrony between these two processes at the ATEs? 2. We used spatial sampling grids at different ATEs in two ecosystems on two subcontinents: Nothofagus pumilio in the Andes of Chilean Patagonia (46° SL) and Pinus albicaulis in the Rockies of Western Montana, USA (46° NL). Basal increment cores were extracted from trees to estimate the growth and recruitment date. An annual detrended basal area increment was estimated for each tree and was modelled against elevation and time. 3. Tree growth improved over multiple centuries at all tree lines. Recently ( c. 50 years), however, improvements are disappearing or reversing. The uppermost tree line trees showed moderate declines in Montana and incipient declines in Patagonia. The declines are most dramatic slightly below current tree line ( c. 200 m). Tree recruitment patterns showed that tree lines have been moving uphill in both regions until at least 40-70 years ago. These movements occurred primarily through abrupt pulses upward with infilling occurring concurrently (Patagonia) or at some time thereafter (Montana). 4. Synchrony between growth and recruitment occurred in the 18th and 19th centuries in both regions. This synchrony was negative in Patagonia and positive in Montana, with varying lag periods. During the 20th century, these patterns of synchrony were lost at all sites. This loss of synchrony suggests that we could be entering a global period in which temperature is no longer the dominant driver of key features of tree lines. 5. Synthesis. Our study shows that at two structurally different tree lines, recent and initial declines in growth and losses of long-term synchrony are occurring in the latter part of the 20th century. These findings are opposite to simplistic expectations of global warming effects on tree line dynamics and call for a model reformulation that uncouples drivers of growth and recruitment. [ABSTRACT FROM AUTHOR]

1 Ecosystem engineers are organisms that change abiotic conditions in ways that affect the performance and distribution of other species, including exotics. Several mechanisms have been proposed for the successful establishment of exotic plants in natural communities, but the positive effects that native engineer species may have on the distribution and performance of exotic plants remain unknown. 2 In this study, we propose that amelioration of extreme abiotic conditions by ecosystem engineers can make stressful habitats invadable by exotic plant species, with larger positive effects on the performance of exotic plants as environmental harshness increases. We tested this hypothesis by assessing the effects of a high-Andean ecosystem engineer, the cushion plant Azorella monantha, which is known to create habitat patches where environmental conditions are less extreme than in the surrounding habitats, on the distribution and the performance of two exotic plant species, field chickweed ( Cerastium arvense) and common dandelion ( Taraxacum officinale), along a an elevation gradient in the Andes of central Chile. 3 We measured and compared the abundance, biomass and survival of both exotic species within and outside cushion habitat patches at three elevations (3200 m, 3400 m and 3600 m), and evaluated whether the effects of A. monantha varied across elevations. 4 The results indicated that cushion plants positively impact the performance of both exotics, and have greater facilitative effects at higher elevations. Indeed, at the higher elevation site, C. arvense was only detected within A. monantha patches, suggesting that cushions may expand the distribution range of exotics. These results suggest that ecosystem engineering by native species could promote biological invasions in harsh environments, leading to higher abundances of invaders than those expected in the absence of engineers. 5 Given the conspicuousness of ecosystem engineering in nature, we suggest that exotic species eradication programmes might be less successful by not taking into account the facilitative effects of native engineer species on invaders. Further, we suggest that the recent proposals to use engineer species in ecosystem restoration should be aware of their potential role in promoting invasions. [ABSTRACT FROM AUTHOR]

Investigates plant phenological patterns in the high Andean Cordillera of Central Chile. Vegetative activity, flowering and fruiting activity; Categories of phenological behavior and their altitudinal distribution; Floral development; Spatial and temporal displacement by competition for light and water.

(1) In south-central Chile, bamboos of the genus Chusquea often dominate the undergrowth of the mainly broad-leaved rain forests, and where these forests have been burned or logged they frequently form dense thickets in which tree regeneration is greatly impeded. (2) Standing crop and above-ground net primary production were estimated for a pure stand of C. culeou at 700 m altitude, and standing crop for C. tenuiflora in the understorey of a mixed Nothofagus betuloides-N. pumilio forest near the timberline at 1040 m in the Andes. (3) Above-ground biomass of the Chusquea culeou thicket and the C. tenuiflora undergrowth was approximately 156-162 t ha[sup -1] and 13.0 t ha[sup -1], respectively. (4) The annual above-ground net primary production for the C. culeou thicket was approximately 10.0-11.4 t ha[sup -1]. [ABSTRACT FROM AUTHOR]

(1) Analysis of the structure of old-growth Nothofagus-dominated forests m the Valdivian Andes indicates that they are not m a steady-state condition. At midelevations the lack of saplings and of relatively small-diameter individuals clearly shows that the shade-intolerant Nothofagus spp are not regenerating in undisturbed old-growth stands. On the other hand, the population structures and reproductive behaviour of the shade-tolerant Laurelia philippiana and Saxegothaea conspicua suggest that in the absence of massive disturbance these species would replace the Nothofagus spp at mid-elevations. (2) The failure of succession to proceed beyond the relatively early successional phase represented by the N dombeyi- and N alpina-dominated forests is a consequence of a long history of periodic natural catastrophes—principally landslides and volcanic eruptions Catastrophic mass movements in the Andes of southcentral Chile, such as those triggered by the devastating 1960 earthquake, periodically destroy or drastically alter thousands of square kilometres of old-growth forest, creating conditions favourable to the establishment of the rapidly growing Nothofagus spp. (3) Models of vegetation change which assume long-term stability of site, and postulate successional development towards a stable end-point, are not fully consistent with the regional importance of the mid-elevation Nothofagus forests of the Valdivian Andes which are maintained by catastrophes A kinetic scheme which does not require a stable end-point for succession and which emphasizes continuous change, even in old-growth forest, is more consistent with the dynamics described for the old-growth forests of the Valdivian Andes. [ABSTRACT FROM AUTHOR]

(1) Mixed evergreen-deciduous Nothofagus forests in south-central Chile, western Patagoma and Magellanic. Chile were studied to determine the influence of the tree dominants on the distribution and dominance of plants in the understorey. (2) In mixed stands of Nothofagus dombeyi-N. pumilio and N. betuloides-N. pumtho near the timberline in south-central. Chile, the understorey dominant Chusquea tenuiflora, a bamboo, is more abundant and taller beneath the evergreen trees Most of the other common species are more abundant and larger under the deciduous N. pumilio. (3) Spring snow-melt is earlier beneath the evergreen Nothofagus spp, resulting in a longer vegetative period in comparison to sites beneath the deciduous trees. During summer, light levels are also greater beneath the evergreen trees Both these habitat differences favour the tall, rapidly-growing bamboos, which, in turn, retard the establishment and growth of herbs, shrubs and tree seedlings beneath the evergreen species. [ABSTRACT FROM AUTHOR]

(1) The vegetation structure on four slopes of different aspect (north, west, east and south) in the mediterranean zone of Chile was analysed. The evergreen and summer-deciduous life-forms are predominant. (2) The south-, east- and west-facing slopes are closely similar in terms of floristic composition, and on these slopes the numbers of species of evergreens and the plant dimensions are greater than on the north-facing slope. Only the latter shows a high cover of summer-deciduous species. This suggests that the four slopes fall on a non-linear moisture gradient, with the north-facing slope at the xeric end. (3) A certain number of hygrophilous species restricted to the south-facing slope are interpreted as relicts of the southern rain forest expansion which occurred during the Pleistocene. The vegetation of the west- and east-facing slopes is most similar to the Chilean matorral. The north-facing .slope contains a component of xeromorphic species which may have invaded from the north. (4) Intensive wood-cutting and/or cattle-grazing of evergreen species in central Chile may have contributed to the high cover of xeromorphic plants. [ABSTRACT FROM AUTHOR]

The article examines the vegetation and soils in the South Chilean Islands. South-western Chile is a mountainous region which has an oceanic climate and evergreen rain forest or peat-forming herbaceous vegetation. The hollows at Chepu on Chiloé Island feature woodland dominated by Nothofagus nitida and Tepualia stipularis, which have waterlogged peaty soils of about 60 percent organic content. Meanwhile, on the central uplands of Chiloé Island peat formation still happen mainly in hollows, and Astelia pumila dominates the bog vegetation.