Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Potential effects of warming and drying on peatland plant community composition (2003)
    Oxford, UK : Blackwell Science, Ltd
    Global change biology 9 (2003), S. 0 
    Details
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Boreal peatlands may be particularly vulnerable to climate change, because temperature regimes that currently constrain biological activity in these regions are predicted to increase substantially within the next century. Changes in peatland plant community composition in response to climate change may alter nutrient availability, energy budgets, trace gas fluxes, and carbon storage. We investigated plant community response to warming and drying in a field mesocosm experiment in northern Minnesota, USA. Large intact soil monoliths removed from a bog and a fen received three infrared warming treatments crossed with three water-table treatments (n = 3) for five years. Foliar cover of each species was estimated annually.In the bog, increases in soil temperature and decreases in water-table elevation increased cover of shrubs by 50% and decreased cover of graminoids by 50%. The response of shrubs to warming was distinctly species-specific, and ranged from increases (for Andromeda glaucophylla) to decreases (for Kalmia polifolia). In the fens, changes in plant cover were driven primarily by changes in water-table elevation, and responses were species- and lifeform-specific: increases in water-table elevation increased cover of graminoids – in particular Carex lasiocarpa and Carex livida– as well as mosses. In contrast, decreases in water-table elevation increased cover of shrubs, in particular A. glaucophylla and Chamaedaphne calyculata. The differential and sometimes opposite response of species and lifeforms to the treatments suggest that the structure and function of both bog and fen plant communities will change – in different directions or at different magnitudes – in response to warming and/or changes in water-table elevation that may accompany regional or global climate change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2486.2003.00571.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Prehistoric, historic, and present settlement patterns related to ecological hierarchy in the Eastern Upper Peninsula of Michigan, U.S.A. (1997)
    Springer
    Landscape ecology 12 (1997), S. 223-240 
    Details
    ISSN: 1572-9761
    Keywords: cultural ecology ; settlement patterns ; landtype associations ; archaeology ; General Land Office surveyors' notes ; LandSAT ; digital elevation model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution of human occupation across a landscape provides informationabout how people use the landscape, about patterns of economic development,and about social interactions of human groups. When the distributions areexamined over several thousand years, we gain an evolutionary understanding,not only of the people and their cultural patterns, but also of physicallandscape development. The focus of this assessment was to examine andcompare settlement patterns of prehistoric, historic, and present timeperiods, based on known cultural sites in the Eastern Upper Peninsula ofMichigan, U.S.A., and to generate hypotheses about the interaction ofsettlement pattern and landscape change at multiple scales. Patterns ofsettlement among the three time periods were compared at three geographicscales: by subregional ecosystems, by landscape ecosystems and by terraincharacteristics. The Michigan Bureau of History database of archaeologicalsites was searched for prehistoric habitation sites of Middle or LateWoodland period (ca. 3000-300 years before present). Historic occupationswere drawn from pre-European settlement landscape data based on General LandOffice survey notes of the 1850s. We extracted “urban” categories from landcover classified from Landsat Thematic Mapper imagery to measure presentoccupations. Spatial patterns and dynamics of settlement areas in each timeperiod were examined using the ARC/INFO geographic information system (GIS).Results showed a tendency for settlement in all time periods on the bedrockand lowland landscape groups near Great Lakes shorelines, generally occupyingslopes less than two percent. The distribution of present occupations, interms of both slope aspect and geographic subregion (multi-scalar), wassimilar to the distribution of prehistoric occupations. Both prehistoric andpresent sites were primarily south facing and were frequently found alongGreen Bay and Lake Michigan shorelines.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007946907682
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Hierarchical relationships between landscape structure and temperature in a managed forest landscape (1998)
    Springer
    Landscape ecology 13 (1998), S. 381-395 
    Details
    ISSN: 1572-9761
    Keywords: hierarchy ; landscape structure ; microclimate ; pattern-process ; scale ; wavelet analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Management may influence abiotic environments differently across time and spatial scale, greatly influencing perceptions of fragmentation of the landscape. It is vital to consider a priori the spatial scales that are most relevant to an investigation, and to reflect on the influence that scale may have on conclusions. While the importance of scale in understanding ecological patterns and processes has been widely recognized, few researchers have investigated how the relationships between pattern and process change across spatial and temporal scales. We used wavelet analysis to examine the multiscale structure of surface and soil temperature, measured every 5 m across a 3820 m transect within a national forest in northern Wisconsin. Temperature functioned as an indicator – or end product – of processes associated with energy budget dynamics, such as radiative inputs, evapotranspiration and convective losses across the landscape. We hoped to determine whether functional relationships between landscape structure and temperature could be generalized, by examining patterns and relationships at multiple spatial scales and time periods during the day. The pattern of temperature varied between surface and soil temperature and among daily time periods. Wavelet variances indicated that no single scale dominated the pattern in temperature at any time, though values were highest at finest scales and at midday. Using general linear models, we explained 38% to 60% of the variation in temperature along the transect. Broad categorical variables describing the vegetation patch in which a point was located and the closest vegetation patch of a different type (landscape context) were important in models of both surface and soil temperature across time periods. Variables associated with slope and microtopography were more commonly incorporated into models explaining variation in soil temperature, whereas variables associated with vegetation or ground cover explained more variation in surface temperature. We examined correlations between wavelet transforms of temperature and vegetation (i.e., structural) pattern to determine whether these associations occurred at predictable scales or were consistent across time. Correlations between transforms characteristically had two peaks; one at finer scales of 100 to 150 m and one at broader scales of 〉300 m. These scales differed among times of day and between surface and soil temperatures. Our results indicate that temperature structure is distinct from vegetation structure and is spatially and temporally dynamic. There did not appear to be any single scale at which it was more relevant to study temperature or this pattern-process relationship, although the strongest relationships between vegetation structure and temperature occurred within a predictable range of scales. Forest managers and conservation biologists must recognize the dynamic relationship between temperature and structure across landscapes and incorporate the landscape elements created by temperature-structure interactions into management decisions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008097011008
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...