| 1. |
- Antonsson, Henrik, 1976, et al.
(författare)
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Nurse plant effect of the cushion plant Silene acaulis (L.) Jacq. in an alpine environment in the subarctic Scandes, Sweden
- 2009
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Ingår i: Plant Ecology & Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 2:1, s. 17-25
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Tidskriftsartikel (refereegranskat)abstract
- Background: Facilitation plays important roles in the structuring of plant communities and several studies have found that it tends to increase with environmental severity in alpine plant communities. In addition, cushion plants have been shown to act as nurse plants, moderating extreme environmental conditions, and providing resources for other species, with substantial effects on local plant diversity. Aims: This study addresses the nurse plant effects of Silene acaulis – a common, circumpolar alpine plant species with a compact cushion-forming growth form – along an altitude transect in the mid- to high-alpine zones in northern Sweden. Methods: The numbers of species in paired S. acaulis cushions and identical-sized control plots along an altitude transect between 1150 m and 1450 m above sea level were compared, and differences in species composition were analysed. Results: At altitudes above c. 1280 m, but not at lower altitudes, more species were found inside the cushions than in their paired control plots. Species composition was similar inside cushions and in control plots. Conclusions: Our results suggest that S. acaulis acts as a nurse plant at altitudes higher than a certain threshold (c. 1280 m at the investigated site). It appears to play an important role in creating focal points for local vascular plant diversity in highalpine environments, where vegetation is open and occurs in small patches. Keywords: facilitation; plant-to-plant interactions; Silene acaulis; species richness; stress
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| 2. |
- Auffret, Alistair G., et al.
(författare)
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Ontogenetic niche shifts in three Vaccinium species on a sub-alpine mountain side
- 2010
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Ingår i: Plant Ecology & Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 3:2, s. 131-139
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Tidskriftsartikel (refereegranskat)abstract
- Background: Climate warming in arctic and alpine regions is expected to result in the altitudinal migration of plant species, but current predictions neglect differences between species' regeneration niche and established niche. Aims: To examine potential recruitment of Vaccinium myrtillus, V. uliginosum and V. vitis-idaea on a mountain slope in northern Sweden in relation to current adult occurrence. Methods: We combined a seed-sowing experiment in seven community types with adult occurrence observations and species distribution mapping. Results: Emergence of V. myrtillus and V. vitis-idaea seedlings was significantly related to community type, while V. uliginosum was indifferent, but exhibited the highest average emergence. Adult occurrence was related to community, and ontogenetic niche shifts were observed for all three study species. V. myrtillus was shown to have the highest potential recruitment in habitats at altitudes above its current populations. Conclusions: The potential for migration exists, but incongruence between regenerative and established niches presents a challenge for colonisers, as well as for plant migration modelling.
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| 3. |
- Belinchon, Rocio
(författare)
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The diversity and community dynamics of hazelwood lichens and bryophytes along a major gradient of human impact
- 2016
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Ingår i: Plant Ecology and Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 9, s. 359-370
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Tidskriftsartikel (refereegranskat)abstract
- Background: Oceanic hazelwoods in western Scotland are hypothesised to be unmanaged post-glacial relicts, representing an unusual type of old-growth forest habitat in Europe. They are characterised by an exceptionally high epiphytic diversity, including their status as hotspots' for indicators of woodland ecological continuity.Aims: The aim of this study was to evaluate the effects of climate, pollution and management on the occurrence of epiphytic lichens and bryophytes on Corylus avellana.Methods: Thirteen hazelwood study sites were systematically sampled along a climate, pollution and management gradient in Britain. Epiphyte composition and richness were examined in a strict hierarchical framework, and compared against site-, stool- and stem-scale environmental predictors.Results: The study showed that along the gradient from clean-air' relict sites to polluted' coppiced sites: (i) epiphytic local stem-scale diversity declined, (ii) there was a loss of late-successional species including foliose cyano- and tripartite lichens and bryophytes and (iii) stem sizes were reduced, providing a further limit to the accumulation of species richness within a site.Conclusions: Relict hazelwoods in western Scotland are confirmed as an example of the most intact epiphyte communities. In particular, we show that the transition to coppicing can be clearly linked to ecological processes causing species loss.
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| 4. |
- Bochenek, Grazyna, 1977, et al.
(författare)
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Annual growth of male and female individuals of the Common Ash (Fraxinus excelsior L.)
- 2010
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Ingår i: Plant Ecology and Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 3:1, s. 47-57
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Tidskriftsartikel (refereegranskat)abstract
- Background: In general, females of woody dioecious plants are expected to grow more slowly than males because of the high cost associated with fruit bearing. Yet wind-pollinated species may invest relatively heavily in male reproduction, and various compensatory mechanisms can offset incurred costs, therefore the apparent growth of genders might be similar over a longer period of time. Any cost-related disparities are expected to be most pronounced in mast flowering years, when female reproductive resource demand is highest. Aims: We aimed to investigate gender-related response in relation to the cost of reproduction, and as a function of climate. Methods: Using dendrochronology techniques and analysing growth parameters at the branch level, we compared long-term and seasonal growth of male and female Fraxinus excelsior trees. Results: There was no observed decline in trunk growth of either of the genders over a 55-year period, but male and female trees had distinguishable annual growth patterns. The tree-ring widths of both genders were smaller in masting years than in other years. The difference between genders could be explained by their response to different climatic variables: females are more sensitive to spring frost and drought in early summer, while male growth depends more on late summer conditions. Conclusions: Vegetative development and flowering create a feedback system that minimises the cost of reproduction and assures that expenses are covered. Hence, growth differences between genders may be related to their phenological and physiological disparities rather than reproductive cost differences per se.
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| 5. |
- Bokhorst, Stef Frederik
(författare)
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Rapid photosynthetic recovery of a snow-covered feather moss and Peltigera lichen during sub-Arctic midwinter warming
- 2013
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Ingår i: Plant Ecology and Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 6, s. 383-392
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Tidskriftsartikel (refereegranskat)abstract
- Conclusions: The moss, and to a lesser extent the lichen, may contribute to subnivean midwinter ecosystem respiration, and both are opportunistic, and can take advantage of warmer winter phases for photosynthesis and growth. This ought to be taken into account in vegetation change projections of cryptogam-rich ecosystems.
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| 6. |
- Caseys, Celine, et al.
(författare)
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Effects of interspecific recombination on functional traits in trees revealed by metabolomics and genotyping-by-resequencing
- 2012
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Ingår i: Plant Ecology & Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 5:4, s. 457-471
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Tidskriftsartikel (refereegranskat)abstract
- Background: Understanding the potential and limits of recombination in adaptive evolution is of great interest to evolutionary biology. New (ultra-) high-throughput technologies in metabolomics and genomics hold great promise for addressing these questions, but their use in interspecific hybrids remains largely unexplored. Aims: Our goal was to test if recombination between the highly divergent genomes of Populus alba and P. tremula has the potential to contribute to the standing variation for functionally important chemical traits. Methods: We studied the metabolomes of interspecific hybrids by ultra-high-pressure liquid chromatography (UHPLC) coupled with quadrupole-time-of-flight (QTOF) mass spectrometry (MS) and initiated the characterisation of hybrid genomes by restriction site associated DNA (RAD) sequencing. Results: UHPLC-QTOF-MS indicated a complex 'mosaic' of chemical traits in recombinant hybrids and pointed to a heritable component for many of these. RAD sequencing confirmed the recombinant nature of natural hybrids previously characterised by microsatellites and suggested a complex history of recombination. Conclusions: It is likely that hybridisation has affected these species' genomes over several glacial cycles. Recombination holds great potential to create functionally relevant chemical variation in these trees. Nevertheless, correlations between chemical traits are not entirely broken up in recombinant hybrids, suggesting limits to adaptive evolution by genetic exchange.
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| 7. |
- Da Re, Daniele, et al.
(författare)
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Global analysis of ecological niche conservation and niche shift in exotic populations of monkeyflowers (Mimulus guttatus, M. luteus) and their hybrid (M. × robertsii)
- 2020
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Ingår i: Plant Ecology & Diversity. - : Taylor & Francis Group. - 1755-0874 .- 1755-1668. ; 13:2, s. 133-146
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Tidskriftsartikel (refereegranskat)abstract
- Background Hybridisation associated with biological invasions may generate new phenotypic combinations, allowing hybrids to occupy new ecological niches. To date, few studies have assessed niche shifts associated with hybridisation in recently introduced populations while simultaneously characterising the niche of parental species in both native and introduced ranges.Aims Here, we compared (1) the ecological niche of a novel hybrid monkeyflower,M. xrobertsii, with the niches of its two parental taxa (M. guttatus, M. luteus), and (2) the ecological niches of native (Americas) and introduced parental populations (Europe and New Zealand).Methods We assembled >13,000 geo-referenced occurrence records and eight environmental variables and conducted an ecological niche model analysis using maximum entropy, principal component and niche dynamics analysis.Results We found no evidence of niche shift in the hybrid, which may result in potential competition between parental and derived taxa in the introduced range.M. guttatusshowed niche conservatism in introduced populations in Europe, but a niche shift in New Zealand, whileM. luteusshowed a niche shift in Europe.Conclusions The comparison of native and non-native populations of parental taxa, suggests that whether invasions result in niche shifts or not depends on both taxon and geographic region, highlighting the idiosyncratic nature of biological invasions.
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| 8. |
- Hofgaard, Annika, et al.
(författare)
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Comparing warming and grazing effects on birch growth in an alpine environment : a 10-year experiment
- 2010
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Ingår i: Plant Ecology & Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 3:1, s. 19-27
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Tidskriftsartikel (refereegranskat)abstract
- Background : Tree encroachment of arctic tundra and alpine vegetation is a generally predicted response to climate warming. However, herbivory plays an important role in structuring these ecosystems and their responses to warming. Aims : To experimentally test how grazing and increased growing season temperature influence growth, physiognomy and stature of birch in the alpine zone. Methods: Trait responses of naturally regenerated birch saplings to warming (open-top chambers), and changed grazing regime (exclosures) were compared with those growing in unmanipulated conditions over a 10-year period (1999–2008). The effect of treatment over time and differences between treatments were analysed with repeated measures GLM (Generalised Linear Model) and simple contrasts in GLM. Results: Warming alone had no major effect on trait responses, however, significantly smaller leaves and an increased number of short shoots indicated warming-related growth constraints. Grazing showed a strong controlling effect on most traits, conserving low stature sapling stage characterised by fewer shoots and larger leaves, compared with non-grazed treatments. Conclusions: Although derived from one experimental site, the results point to a grazing-controlled response to environmental change, with climate (warming) as a secondary driver. This herbivore-driven masking of expected climate-driven tree expansion emphasises the necessity to consider changes in grazing regimes along with climate change, in order to avoid misleading interpretations regarding climate-driven tundra encroachment.
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| 9. |
- Huaraca Huasco, Walter, et al.
(författare)
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Seasonal production, allocation and cycling of carbon in two mid-elevation tropical montane forest plots in the Peruvian Andes
- 2014
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Ingår i: Plant Ecology & Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 7:1-2, s. 125-142
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tropical montane cloud forests (TMCF) are unique ecosystems with high biodiversity and large carbon reservoirs. To date there have been limited descriptions of the carbon cycle of TMCF. Aims: We present results on the production, allocation and cycling of carbon for two mid-elevation (1500-1750 m) tropical montane cloud forest plots in San Pedro, Kosnipata Valley, Peru. Methods: We repeatedly recorded the components of net primary productivity (NPP) using biometric measurements, and autotrophic (R-a) and heterotrophic (Rh) respiration, using gas exchange measurements. From these we estimated gross primary productivity (GPP) and carbon use efficiency (CUE) at the plot level. Results: The plot at 1500 m was found very productive, with our results comparable with the most productive lowland Amazonian forests. The plot at 1750 m had significantly lower productivity, possibly because of greater cloud immersion. Both plots had similar patterns of NPP allocation, a substantial seasonality in NPP components and little seasonality in R-a. Conclusions: These two plots lie within the ecotone between lower and upper montane forests, near the level of the cloud base. Climate change is likely to increase elevation of the cloud base, resulting in shifts in forest functioning. Longer-term surveillance of the carbon cycle at these sites would yield valuable insights into the response of TMCFs to a shifting cloud base.
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| 10. |
- Lascoux, Martin, et al.
(författare)
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Past demography in forest trees : what can we learn from nuclear DNA sequences that we do not already know?
- 2008
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Ingår i: Plant Ecology & Diversity. - : Informa UK Limited. - 1755-0874 .- 1755-1668. ; 1:2, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- Acquiring nuclear DNA sequences in forest tree species is becoming easier as molecular tools are developing rapidly and we now have at our disposal an array of theoretical methods to carry out statistical inferences from multilocus sequence variation. In the present article we use results from two recent studies of nuclear DNA sequence polymorphism in Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) to illustrate what additional insights to each species' history can be gained compared with classical phylogeographic studies based on chloroplast or mitochondrial DNA. The sampling schemes and statistical analyses used in these two studies were similar facilitating a comparison between them. In both cases we inferred the presence of a rather severe bottleneck predating the Last Glacial Maximum (∌18,000 years ago). This result is discussed in relation to recent reassessments of the fossil pollen record and to its implication for our understanding of adaptation. Finally we briefly outline some suggestions for future research.
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