Glacier Forelands: Lessons of Plant Population and Community Development
01 Jan 2016-pp 259-284
TL;DR: In this paper, the authors summarize the results of several case studies from the Austrian and Italian Alps, draw conclusions and highlight research gaps, and conclude that the already established species are the ones which contribute most to the genesis of a seed bank; an input of seeds by long distance dispersal was hardly detected.
Abstract: After glacier retreat, the ice-free forelands arise as easily detectable landforms where primary succession starts from the beginning onwards. Here, basic ecological lessons of colonization and community development can be learned. In this review we summarize the results of several case studies from the Austrian and Italian Alps, draw conclusions and highlight research gaps. Glacier foreland species exhibit a considerable intra-population diversity. Actual gene flow was shown to be high enough to maintain the genetic diversity throughout all successional stages. Most seeds of the glacier foreland species are light-weighted and wind-dispersed. Heavier seeds with no specific dispersal traits such as those of certain late successional species will hardly be dispersed to the pioneer stages. In most glacier forelands, a seed bank has to be developed from zero onwards. The already established species are the ones which contribute most to the genesis of a seed bank; an input of seeds by long distance dispersal was hardly detected. A relatively high quantity of glacier foreland species has a deep physiological dormancy. Thus, they will be able to form persistent seed banks. Seedling recruitment is highly governed by drought and seed availability. Additionally, frost and heat might be essential abiotic factors for germination and seedling survival. Growth rates of the glacier foreland species vary considerably among the successional stages and seem to be phylogenetically constrained. Population growth rates are characterised by low seedling recruitment and/or high mortality rates of the seedlings; some species overcome this low reproductive success by clonal growth strategies. From seed sowing experiments we learned that facilitation and competition may occur side by side. However, this topic has to be further explored in the future. By means of plant functional types, the pioneer species were classified as fast-growing ruderal strategists. In contrast, late successional stages harbour mainly stress-tolerant species with dense leaves and low relative growth rates. Phytosociological community descriptions are a challenging topic in glacier forelands. Nevertheless, several communities were described mainly from the Italian Alps. One of the less investigated topics, although being essential in ecology, is the species interaction issue. Among the scarce studies in this context, pollination and flower-visiting insects were studied. Species interactions including different organismic levels as well as species adaptations to changing conditions are still topics to be studied along glacier forelands. Climate warming probably will enhance the speed and the pathway of colonization. If glacier forelands can act as refugia for alpine-nival species remains to be proved. Thus, glacier foreland offer ample ecological questions and further research is highly recommended.
Citations
More filters
TL;DR: It is suggested that, despite the accelerating rate of warming, the dynamics of primary succession remains slow, generating a climatic debt and hampering the adaptation to climate change in alpine plant communities.
Abstract: Species range shifts and possible species extinctions in alpine regions are hypothesized being influenced by the increasing time lag between the velocity of global warming and the slowness of primary succession. We tested this hypothesis in tropical alpine environments above 4700 m a.s.l. (Central Andes) and we explored the underlying mechanisms at work by using four sites gradually deglaciated since the acceleration of warming in the late 1970’s. These post-glacial chronosequences, made available by a multidisciplinary approach combining glaciology and ecology, are extremely rare and provide a pertinent space-for-time substitution for the study of climate change effects. We found consistent patterns in plant succession (abundance, species richness and functional strategies) along the four chronosequences. Dispersal limitation was a prominent constraint for succession, even at the end of the chronosequences, leading to an overrepresentation of anemochorous species in comparison with adjacent ecosystems. Nurse plants were infrequent and their low maturity seemed to make them poorly efficient as facilitators, contrarily to the expectations made by the stress-gradient hypothesis in alpine regions. This suggests that, despite the accelerating rate of warming, the dynamics of primary succession remains slow, generating a climatic debt and hampering the adaptation to climate change in alpine plant communities.
55 citations
Cites background from "Glacier Forelands: Lessons of Plant..."
...…tropical alpine regions may exacerbate the dispersal filter with new species assemblages being even more dominated by anemochorous species than what has been observed along longer postglacial chronosequences, so far (Stöcklin and Bäumler, 1996; Erschbamer and Caccianiga, 2016; Marta et al., 2016)....
[...]
..., 2016)? And (2) would the short time available for the development of alpine nurse plants in recently deglaciated sites impact negatively plant communities because of limited ontogenic variations between the nurse and the beneficiary (Anthelme and Dangles, 2012)? More generally, how the various pioneer organisms interact early after glacial retreat is poorly known and requires further investigation (Matthews and Vater, 2015; Erschbamer and Caccianiga, 2016)....
[...]
...As observed and interpreted in the Alps, this shift may indicate a first colonization step by R-strategists taking advantage of glacial till deposit thanks to their rapid phenological development (Caccianiga et al., 2006; Erschbamer and Caccianiga, 2016)....
[...]
...The dominance of anemochorous species early after glacial retreat is a classical feature observed along post-glacial chronosequences (Stöcklin and Bäumler, 1996; Erschbamer and Caccianiga, 2016)....
[...]
...More generally, how the various pioneer organisms interact early after glacial retreat is poorly known and requires further investigation (Matthews and Vater, 2015; Erschbamer and Caccianiga, 2016)....
[...]
TL;DR: In this study, in situ vegetation sampling along a chronosequence between Little Ice Age maximum extent and the recent glacier terminus at Jamtalferner in the Austrian Alps is compared to time series of the Normalized Difference Vegetation Index (NDVI), calculated from 13 Landsat scenes (1985–2016).
Abstract: Monitoring of plant succession in glacier forelands has so far been restricted to field sampling. In this study, in situ vegetation sampling along a chronosequence between Little Ice Age (LIA) maximum extent and the recent glacier terminus at Jamtalferner in the Austrian Alps is compared to time series of the Normalized Difference Vegetation Index (NDVI) calculated from 13 Landsat scenes (1985–2016). The glacier terminus positions at 16 dates between the LIA maximum and 2015 were analysed from historical maps, orthophotos and LiDAR images. We sampled plots of different ages since deglaciation, from very recent to approx. 150 years: after 100 years, roughly 80% of the ground is covered by plants and ground cover does not increase significantly thereafter. The number of species increases from 10–20 species on young sites to 40–50 species after 100 years. The NDVI increases with the time of exposure from a mean of 0.11 for 1985–1991 to 0.20 in 2009 and 0.27 in 2016. As the increase in ground cover is clearly reproduced by the NDVI (R² ground cover/NDVI 0.84) – even for sparsely vegetated areas –, we see a great potential of satellite-borne NDVI to perform regional characterizations of glacier forelands for hydrological, ecological and hazard management-related applications.
23 citations
TL;DR: The nature of the timescale, patterns and environmental factors, and the ecological significance of recently-deglaciated terrain are discussed.
Abstract: 1. Introduction 2. The nature of the timescale 3. The physical landscape 4. Soil development 5. Plant succession: patterns and environmental factors 6. Plant succession: processes and models 7. The ecological significance of recently-deglaciated terrain.
14 citations
10 citations
Cites background from "Glacier Forelands: Lessons of Plant..."
...However, a different successional pathway is started due to the proximity of a mature seed pool (Fastie, 1995; Cichini et al., 2011; Erschbamer & Caccianiga, 2016)....
[...]
TL;DR: This study presents a germination screening of seeds from 255 species of the European Eastern Alps, which were to be stored at the Millennium Seed Bank, and provides ecological insights of the species tested.
Abstract: Storing seeds in seed banks is an effective way to preserve plant diversity and conserve species. An essential step towards a valuable conservation is the validation of germination. This study presents a germination screening of seeds from 255 species of the European Eastern Alps, which were to be stored at the Millennium Seed Bank (Kew, UK). The final germination percentage (FGP) was determined using a standard protocol in the laboratory. Species were classified according to species rarity, plant community, occurrence at elevation belts, bedrock types, as well as CSR strategies, and further, seed mass was examined. We could not find statistically significant differences of FGP within these classes, but 74.9% of all tested species germinated using the standard protocol, and half of them had FGP ≥ 20.1–100%. A treatment with gibberellic acid enhanced the germination in half of the species to which this treatment was applied. Common families in alpine regions, i.e. Asteraceae, Poaceae and Saxifragaceae were highlighted in terms of their germination behaviour. The results provide an evaluation of the application of standard protocols to a broad Alpine species pool on the one hand, and on the other hand, provide ecological insights of the species tested. Germination is not only one of the most important events of the reproductive cycle of plants but could also be a key feature in species' responses to changing environmental conditions.
9 citations
References
More filters
Book•
01 Jan 1979
TL;DR: In this paper, the authors present plant strategies in the established phase and the regenerative phase in the emerging phase, respectively, and discuss the relationship between the two phases: primary strategies and secondary strategies.
Abstract: PLANT STRATEGIES. Primary Strategies in the Established Phase. Secondary Strategies in the Established Phase. Regenerative Strategies. VEGETATION PROCESSES. Dominance. Succession. Co-Existence. References. Index.
5,687 citations
TL;DR: In the majority of natural communities succession is frequently interrupted by major disturbances, such as fires, storms, insect plagues, etc., starting the process all over again, but if not interrupted, it eventually reaches a stage in which further change is on a small scale as individuals die and are replaced.
Abstract: The sequence of species observed after a relatively large space is opened up is a consequence of the following mechanisms. "Opportunist" species with broad dispersal powers and rapid growth to maturity usually arrive first and occupy empty space. These species cannot invade and grow in the presence of adults of their own or other species. Several alternative mechanisms may then determine which species replace these early occupants. Three models of such mechanisms have been proposed. The first "facilitation" model suggests that the entry and growth of the later species is dependent upon the earlier species "preparing the ground"; only after this can later species colonize. Evidence in support of this model applies mainly to certain primary successions and in heterotrophic succession. A second "tolerance" model suggests that a predictable sequence is produced by the existence of species that have evolved different strategies for exploiting resources. Later species will be those able to tolerate lower levels...
4,068 citations
TL;DR: Evidence for the importance of positive interactions - facilitations - in community organization and dynamics has accrued to the point where it warrants formal inclusion into community ecology theory, as it has been in evolutionary biology.
Abstract: Current concepts of the role of interspecific interactions in communities have been shaped by a profusion of experimental studies of interspecific competition over the past few decades. Evidence for the importance of positive interactions — facilitations — in community organization and dynamics has accrued to the point where it warrants formal inclusion into community ecology theory, as it has been in evolutionary biology.
3,107 citations
Book•
[...]
01 Jan 1999
TL;DR: In this article, a taxonomic index (genera) of alpine plants is presented, with a brief review of water relations and water relations of alpin plants in the alpine life zone.
Abstract: 1 Plant ecology at high elevations.- The concept of limitation.- A regional and historical account.- The challenge of alpine plant research.- 2 The alpine life zone.- Altitudinal boundaries.- Global alpine land area.- Alpine plant diversity.- Origin of alpine floras.- Alpine growth forms.- 3 Alpine climate.- Which alpine climate.- Common features of alpine climates.- Regional features of alpine climates.- 4 The climate plants experience.- Interactions of relief, wind and sun.- How alpine plants influence their climate.- The geographic variation of alpine climate.- 5 Life under snow: protection and limitation.- Temperatures under snow.- Solar radiation under snow.- Gas concentrations under snow.- Plant responses to snowpack.- 6 Alpine soils.- Physics of alpine soil formation.- The organic compound.- The interaction of organic and inorganic compounds.- 7 Alpine treelines.- About trees and lines.- Current altitudinal positions of climatic treelines.- Treeline-climate relationships.- Intrazonal variations and pantropical plateauing of alpine treelines.- Treelines in the past.- Attempts at a functional explanation of treelines.- A hypothesis for treeline formation.- Growth trends near treelines.- Evidence for sink limitation.- 8 Climatic stress.- Survival of low temperature extremes.- Avoidance and tolerance of low temperature extremes.- Heat stress in alpine plants.- Ultraviolet radiation - a stress factor.- 9 Water relations.- Ecosystem water balance.- Soil moisture at high altitudes.- Plant water relations - a brief review of principles.- Water relations of alpine plants.- Desiccation stress.- Water relations of special plant types.- 10 Mineral nutrition.- Soil nutrients.- The nutrient status of alpine plants.- Nutrient cycling and nutrient budgets.- Nitrogen fixation.- Mycorrhiza.- Responses of vegetation to variable nutrient supply.- 11 Uptake and loss of carbon.- Photosynthetic capacity of alpine plants.- Photosynthetic responses to the environment.- Daily carbon gain of leaves.- The seasonal carbon gain of leaves.- C4 and CAM photosynthesis at high altitudes.- Tissue respiration of alpine plants.- Ecosystem carbon balance.- 12 Carbon investments.- Non-structural carbohydrates.- Lipids and energy content.- Carbon costs of leaves and roots.- Whole plant carbon allocation.- 13 Growth dynamics and phenology.- Seasonal growth.- Diurnal leaf extension.- Rates of plant dry matter accumulation.- Functional duration of leaves and roots.- 14 Cell division and tissue formation.- Cell size and plant size.- Mitosis and the cell cycle.- From meristem activity to growth control.- 15 Plant biomass production.- The structure of alpine plant canopies.- Primary productivity of alpine vegetation.- Plant dry matter pools.- Biomass losses through herbivores.- 16 Plant reproduction.- Flowering and pollination.- Seed development and seed size.- Germination.- Alpine seed banks and natural recruitment.- Clonal propagation.- Alpine plant age.- Community processes.- 17 Global change at high elevation.- Alpine land use.- The impact of altered atmospheric chemistry.- Climatic change and alpine ecosystems.- References (with chapter annotation).- Taxonomic index (genera).- Geographical index.- Color plates.- Plant life forms.- The alpine life zone.- Environmental stress.- The human dimension.
2,971 citations
TL;DR: Crossfertilization between approaches based on species richness on the one hand, and on functional traits and types on the other, is a promising way of gaining mechanistic insight into the links between plant diversity and ecosystem processes and contributing to practical management for the conservation of diversity andcosystem services.
Abstract: The links between plant diversity and ecosystem functioning remain highly controversial. There is a growing consensus, however, that functional diversity, or the value and range of species traits, rather than species numbers per se, strongly determines ecosystem functioning. Despite its importance, and the fact that species diversity is often an inadequate surrogate, functional diversity has been studied in relatively few cases. Approaches based on species richness on the one hand, and on functional traits and types on the other, have been extremely productive in recent years, but attempts to connect their findings have been rare. Crossfertilization between these two approaches is a promising way of gaining mechanistic insight into the links between plant diversity and ecosystem processes and contributing to practical management for the conservation of diversity and ecosystem services.
2,756 citations