Statistics for Spatial Data.

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.

Alpine plant life

Climate change due to greenhouse gas emissions is predicted to raise the mean global temperature by 1.0–3.5°C in the next 50–100 years. The direct and indirect effects of this potential increase in temperature on terrestrial ecosystems and ecosystem processes are likely to be complex and highly varied in time and space. The Global Change and Terrestrial Ecosystems core project of the International Geosphere-Biosphere Programme has recently launched a Network of Ecosystem Warming Studies, the goals of which are to integrate and foster research on ecosystem-level effects of rising temperature. In this paper, we use meta-analysis to synthesize data on the response of soil respiration, net N mineralization, and aboveground plant productivity to experimental ecosystem warming at 32 research sites representing four broadly defined biomes, including high (latitude or altitude) tundra, low tundra, grassland, and forest. Warming methods included electrical heat-resistance ground cables, greenhouses, vented and unvented field chambers, overhead infrared lamps, and passive night-time warming. Although results from individual sites showed considerable variation in response to warming, results from the meta-analysis showed that, across all sites and years, 2–9 years of experimental warming in the range 0.3–6.0°C significantly increased soil respiration rates by 20% (with a 95% confidence interval of 18–22%), net N mineralization rates by 46% (with a 95% confidence interval of 30–64%), and plant productivity by 19% (with a 95% confidence interval of 15–23%). The response of soil respiration to warming was generally larger in forested ecosystems compared to low tundra and grassland ecosystems, and the response of plant productivity was generally larger in low tundra ecosystems than in forest and grassland ecosystems. With the exception of aboveground plant productivity, which showed a greater positive response to warming in colder ecosystems, the magnitude of the response of these three processes to experimental warming was not generally significantly related to the geographic, climatic, or environmental variables evaluated in this analysis. This underscores the need to understand the relative importance of specific factors (such as temperature, moisture, site quality, vegetation type, successional status, land-use history, etc.) at different spatial and temporal scales, and suggests that we should be cautious in "scaling up" responses from the plot and site level to the landscape and biome level. Overall, ecosystem-warming experiments are shown to provide valuable insights on the response of terrestrial ecosystems to elevated temperature.

/pdf/a-meta-analysis-of-the-response-of-soil-respiration-net-4y6fejl9qw.pdf

A meta-analysis of the response of soil respiration, net nitrogen mineralization, and aboveground plant growth to experimental ecosystem warming

Experimental evidence for positive interactions, or facilitation, among plants has increased markedly during the last 10 years. Experiments documenting facilitation have been conducted in many diverse ecological systems, which suggests that positive interactions may be fundamental processes in plant communities. Here, I review the evidence for facilitation, the mechanisms by which facilitation operates, and the effects facilitation has on community structure. Facilitative mechanisms may act simultaneously with resource competition or allelopathy, and the overall effect of one species on another may be the product of multiple, complex interactions. Positive interactions may also determine community spatial patterns, permit coexistence, enhance diversity and productivity, and drive community dynamics. Once viewed as anecdotal and idiosyncratic, facilitation is now contributing to a more complete understanding of community structure and dynamics.

Positive interactions among plants

▪ Abstract Recent overviews have suggested that the relationship between species richness and productivity (rate of conversion of resources to biomass per unit area per unit time) is unimodal (hump-shaped). Most agree that productivity affects species richness at large scales, but unanimity is less regarding underlying mechanisms. Recent studies have examined the possibility that variation in species richness within communities may influence productivity, leading to an exploration of the relative effect of alterations in species number per se as contrasted to the addition of productive species. Reviews of the literature concerning deserts, boreal forests, tropical forests, lakes, and wetlands lead to the conclusion that extant data are insufficient to conclusively resolve the relationship between diversity and productivity, or that patterns are variable with mechanisms equally varied and complex. A more comprehensive survey of the ecological literature uncovered approximately 200 relationships, of which 3...

The Relationship Between Productivity and Species Richness

Of the world's major biomes, tundras, including Antarctica and Green­ land, occupy about 15% of the land surface. These treeless areas, above treeline (alpine ) or beyond treeline latitudinally (arctic ) , contain relatively few plant species. The plants that are preadapted to tundras have bcen se­ lected by environmental regimes that contain less biologically usable energy than in other biomes. Yet Hare (78 ) has shown that even in the Canadian Archipelago the Arctic is not a heat sink on a yearly basis, for solar radia­ tion amounts to 35-40 kilolangleys/year (0-5 kly /year in net radiation), compared with 1 5-20 kly/year at treeline in Alaska and Keewatin. While altitudinal and latitudinal treeline conforms quite well to the lOoC mean for the warmest month, Bryson (46 ) reports that the northern limit of trees also corresponds with the southern limit of the arctic frontal zone in sum­ mer. This dynamic boundary may be controlled by vegetational differences in albedo and surface roughness. The functioning of plants, as influenced directly and indirectly by tem­ perature, becomes central in determining the various strategies that have evolved to enable them to cope with these heat-deficient ecosystems. The purpose of this review is to bring together recent information and theories on the adaptive mechanisms which enable plants to survive and function in environments with cool, short summers and cold, long winters-save for tropical alpine environments where "winter" comes nearly every night­ and, where possible, to relate these findings to the pattern of species and communities in different tundras. Much research has been done in recent years on the floristics, plant com­ munities, soils, ecophysiology, and now the ecosystems of different tundras. A few key books and articles that speak to this background of information are those of Schroeter ( 169 ) , S0rensen (176 ) , Polunin ( 1 50, 152 ) , Bliss

Arctic and Alpine Plant Life Cycles

Discusses tundra environments, i.e. beyond the climatic timberline, mostly in Alaska, Canada, Greenland, and USSR, and various mechanisms used by plants in adapting to them. Despite a very short growing season with low air and soil temperatures, adverse wind effects, and a low nitrogen-utilization level, tundra plants are well adapted to their environment. They are apparently efficient converters of energy, due partly to their utilization of much of the growing season for growth and development, their use of considerable carbohydrate reserves of the previous year, and the higher caloric values of the species.

https://journalhosting.ucalgary.ca/index.php/arctic/article/download/66614/50527

Adaptations of Arctic and Alpine Plants to Environmental Conditions

Tundra ecosystems: a comparative analysis.

Studies of flowering, germination, and seedling survival were conducted in various stable and unstable soil (surface scraped and surface tilled) sites on King Christian Island, N.W.T., Canada. Although most species flowered, few set seed in 1973 or 1974. Germination was slow (3 to 6 wk), occurring only after spring snowmelt or summer rains when there were thin films of standing water. Field

L. C. Bliss

Papers

Arctic and Alpine Plant Life Cycles

Adaptations of Arctic and Alpine Plants to Environmental Conditions

Tundra ecosystems: a comparative analysis.

Plant reproduction in a high arctic environment

Arctic Tundra Ecosystems