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The average growth and size distributions of Douglas-fir (Pseudotsuga menziesii) saplings in three plantations were studied for 7 years (1983–1989) after thinning of associated sprout clumps of tanoak (Lithocarpus densiflorus) or Pacific madrone (Arbutus menziesii); in some cases understory vegetation (shrubs and herbs) was experimentally suppressed. Biologically based nonlinear equations explained 66, 90, and 53% of the variation in the average annual increment of Douglas-fir height, diameter-squared, and cover, respectively. Equations for annual increment of cover of hardwood and understory vegetation explained only 10 to 12% of the variation, because these parameters exhibited a high degree of variability. Model simulations demonstrated that, for the same initial levels of cover, tanoak had faster rates of cover growth than madrone and also caused greater limitations in growth of Douglas-fir. Suppression of understory vegetation increased growth of Douglas-fir only when hardwood cover was absent. Weibull functions adequately described size distributions for Douglas-fir in 92% of the individual-tree data sets. Regression functions of hardwood cover and average Douglas-fir size explained 51, 93, and 24% of the variation in the Weibull A, B, and C parameters, respectively. Model simulations with predicted Weibull parameters demonstrated that hardwood competition caused a positive skewing in size distributions for height and stem diameter of Douglas-fir. 相似文献
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Brigitte Moser Jochen A. G. Jaeger Ulrike Tappeiner Erich Tasser Beatrice Eiselt 《Landscape Ecology》2007,22(3):447-459
Patch-based landscape metrics can be biased by the boundaries and the extent of a reporting unit if the boundaries fragment
patches. We call this the “boundary problem”. The effective mesh size m
eff is a convenient method to quantify landscape fragmentation, that is based on the probability that two points chosen randomly
in a region will be connected, e.g., not be separated by roads, railroads, or urban development. The cutting-out (CUT) procedure,
used in the original computation of m
eff, suffers from the boundary problem because the boundaries of the reporting units are considered to be additional barriers.
Therefore, m
eff will be underestimated, particularly if reporting units are embedded within the broader landscape. In this paper, we present
a solution to overcome this limitation by a new method called “cross-boundary connections” (CBC) procedure. It attributes
the connections between two points that are located in different reporting units to both reporting units. We systematically
compare the CBC procedure to the CUT procedure and show that the boundary problem is intrinsic to the CUT procedure, while
the CBC procedure is independent of the size and administrative boundaries of reporting units. In addition, we elucidate the
superior performance of the new procedure in the case study of South Tyrol where m
eff is being used for sustainability reporting on the level of municipalities. The new CBC procedure eliminates the bias due
to the boundaries and the size of reporting units in measuring landscape fragmentation through m
eff. 相似文献
14.
Purpose
Symbolic plants and animals are recognised as a cultural ecosystem service (CES), which is still underrepresented in ecosystem services assessments. Thus, this study aims at identifying and mapping important symbolic species in the European Alps, which are of cultural significance to large parts of the Alpine population.Methods
Symbolic species were identified by ten expert groups, and their use was assessed in a qualitative way. The spatial distribution of all species across the Alpine Space area was mapped at the municipality level. Through hotspots analysis, we identified spatial patterns in the distribution of species. Spearman correlation was used to evaluate the relationship between symbolic species and selected environmental and social variables.Results
Ten species were identified (edelweiss, gentian, alpenrose, larch, pine, Alpine ibex, chamois, marmot, brown bear, and golden eagle) that are widely used for symbolic representations, i.e., depiction on flags, emblems, logos, and naming of hotels and brands. Hotspots of symbolic species were found in several locations in the European Alps and could be related to high elevation, steep slopes, open land cover, and naturalness.Conclusions
This study proposes a methodology to map and assess symbolic species as a CES. As the spatial distribution of symbolic species depends on environmental characteristics and human activities, our results provide important insights for landscape planning and management. However, it remains unclear whether associated cultural values depend on the presence of the species and further research is needed to understand the relationships between the distribution of symbolic species and social benefits.15.
Lukas?Egarter ViglEmail author Uta?Schirpke Erich?Tasser Ulrike?Tappeiner 《Landscape Ecology》2016,31(9):1903-1918
Context
Human driven land-use and land-cover change (LULC) is considered to be among the greatest ecological pressures in mountain regions. Over the past century, across the European Alps, extensive LULC changes have been observed, affecting ecosystem goods and services (ESs).Objectives
For eight case study sites across the Alpine arc we aimed to provide a spatiotemporal explicit assessment of the impacts of LULC dynamics on ES provision and interactions, including cultivated crops, plant material, climate regulation, soil erosion control and aesthetics.Methods
We quantified ES provision in biophysical terms at four time periods (1850, 1955, 1985, 2005) using spatially explicit LULC based assessment models. ES interactions were identified by statistically analyzing the spatiotemporal pattern among ES capacities.Results
Over the past century forested areas have increased mainly at the cost of grasslands, while on easily accessible sites and fertile valley floors agricultural intensification occurred. ES provision shifted between 1850 and 2005, from a predominance of production ESs in 1850 to a landscape characterized by regulating ESs in 2005. Spatiotemporal analyses of ES interactions revealed trade-offs between regulating and cultural ESs and within the provisioning ES bundle and allowed to derive three different ES trajectories: regions developing from single to multifunctional sites in terms of service provision, sites reducing their service capacities and sites with rather stationary patterns over broad time periods.Conclusions
We demonstrated that ES capacities in complex agro-ecological mountain regions are highly sensitive to long-term landscape dynamics. We conclude that assessing ES capacities and interactions in an explicitly spatiotemporal manner can help to guide evidence-based environmental measures.16.
A field study was conducted to investigate the effect of abandonment of management on net N mineralization (NNM) in subalpine
meadows. NNM, soil microbial biomass N (SMBN), fungal biomass and physicochemical characteristics (total C, total N, dissolved
organic carbon (DOC) and pH) were determined in surface (0–10 cm) soil from May to October 1997 in an intensively managed
and an abandoned meadow at 1770 m a.s.l.. The cumulative NNM was lower in the abandoned area and ranged from 150 to 373 and
from 25 to 85 μg N g–1 soil in the intensively managed and the abandoned areas, respectively. The total organic C increased in the abandoned area,
while total N showed no difference between abandoned and managed meadow. SMBN showed no difference between the investigated
sites, whereas ergosterol, a measure of fungal biomass, increased significantly at the abandoned site. The cumulative NNM
was negatively correlated with total organic C, C : N ratio, DOC and ergosterol content, and positively correlated with the
NH4
+-N content of soil. The decrease in NNM at the abandoned site may be explained by the lower availability of N in substrates
characterized by a high C : N ratio which, together with a decrease in pH in the litter layer, may have increased fungal biomass.
Received: 8 January 1999 相似文献
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Angelstam Per Manton Michael Elbakidze Marine Sijtsma Frans Adamescu Mihai Cristian Avni Noa Beja Pedro Bezak Peter Zyablikova Iryna Cruz Fatima Bretagnolle Vincent Díaz-Delgado Ricardo Ens Bruno Fedoriak Mariia Flaim Giovanna Gingrich Simone Lavi-Neeman Miri Medinets Sergey Melecis Viesturs Muñoz-Rojas Jose Schäckermann Jessica Stocker-Kiss Andrea Setälä Heikki Stryamets Natalie Taka Maija Tallec Gaelle Tappeiner Ulrike Törnblom Johan Yamelynets Taras 《Landscape Ecology》2019,34(7):1461-1484
Landscape Ecology - Place-based transdisciplinary research involves multiple academic disciplines and non-academic actors. Long-Term Socio-Ecological Research (LTSER) platform is one concept with ~... 相似文献