. Abstract Research on fragmented ecosystems has focused mostly on the biogeograpbic consequences of the creation of habitat “islands” of different sizes and has provided little of practical value to managers. However, ecosystem fragmentation causes large changes in the physical environment as well as biogeograpbic changes. Fragmentation generally results in a landscape that consists of remnant areas of native vegetation surrounded by a matrix of agricultural or other developed land. As a result fluxes of radiation, momentum (La, wind), water, and nutrients across the landscape are altered significantly. These in turn can have important influences on biota within remnant areas, especially at or near the edge between the remnant and the surrounding matrix. The isolation of remnant areas by clearing also has important consequences for the biota. These consequences vary with the time since isolation distance from other remnants, and degree of connectivity with other remnants. The influences of physical and biogeographic changes are modified by the size, shape, and position in the landscape of individual remnant, with larger remnants being less adversely affected by the fragmentation process. The Dynamics of remnant areas are predominantly driven by factors arising in the surrounding landscape. Management of, and research on, fragmented ecosystems should be directed at understanding and controlling these external influences as much as at the biota of the remnants themselves. There is a strong need to develop an integrated approach to landscape management that places conservation reserves in the context of the overall landscape

Vegetation and the Atmosphere, Volume 1: Principles

Biological consequences of ecosystem fragmentation: a review

/pdf/biological-consequences-of-ecosystem-fragmentation-a-review-2z02qtnwxh.pdf

Biological Consequences of Ecosystem Fragmentation: A Review

Formation of the American Society for Photobiology for meeting the needs of investigators studying the effects of light on man and other organisms is described. The scientific program of the first meeting of the society included discussions of the followiug topics: detrimental effects of excessive exposure to sunlight and artificial uv radiation; repair of uv-induced damage to cells; the roles of light in the human environnnent; photochemistry in photobiology; effects of near uv light; photosynthesis; bioluminescence; light perception without eyes; chronobiology; the ultraviolet world of insects; vision; and solar energy conversion. (HLW)

background

The Science of Photobiology

Numerical simulation and experiments of burning douglas fir trees

Earlier impact studies have suggested that climate change may severely alter the hydro- logical cycle in alpine terrain. However, these studies were based on the use of a single or a few cli- mate scenarios only, so that the uncertainties of the projections could not be quantified. The present study helps to remedy this deficiency. For 2 Alpine river basins, the Thur basin (1700 km 2 ) and the Ticino basin (1515 km 2 ), possible future changes in the natural water budget relative to the 1981-2000 (Thur) and 1991-2000 (Ticino) baselines were investigated by driving the distributed catchment model WaSiM-ETH with a set of 23 regional climate scenarios for monthly mean tem- perature (T) and precipitation (P). The scenarios referred to 2081-2100 and were constructed by applying a statistical-downscaling technique to outputs from 7 global climate models. The statistical- downscaling scenarios showed changes in annual mean T between +1.3 and +4.8°C and in annual total P between -11 and +11%, with substantial variability between months and catchments. The simulated overall changes in the hydrological water cycle were qualitatively robust and independent of the choice of a particular scenario. In all cases, the projections showed strongly decreased snow- pack and shortened duration of snow cover, resulting in time-shifted and reduced runoff peaks. Sub- stantial reductions were also found in summer flows and soil-water availability, in particular at lower elevations. However, the magnitudes and certain aspects of the projected changes depended strongly on the choice of scenario. In particular, quantitative projections of soil moisture in the summer season and of the runoff in both the summer and autumn seasons were found to be quite uncertain, mainly because of the uncertainty present in the scenarios for P. Our findings clearly demonstrate that quantitative assessments of hydrological changes in the Alps using only a small number of scenarios may yield misleading results. This work strengthens our confidence in the overall results obtained in earlier studies and suggests distinct shifts in future Alpine hydrological regimes, with potentially dramatic implications for a wide range of sectors.

/pdf/differential-impacts-of-climate-change-on-the-hydrology-of-3y7juq16wp.pdf

Vegetation and the Atmosphere, Volume 1: Principles

Citations

Biological consequences of ecosystem fragmentation: a review

Biological Consequences of Ecosystem Fragmentation: A Review

The Science of Photobiology

Numerical simulation and experiments of burning douglas fir trees

Differential impacts of climate change on the hydrology of two alpine river basins

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