scholarly journals Changes in diatom patch-size distribution and degradation in a spatially self-organized intertidal mudflat ecosystem

Ecology ◽  
2012 ◽  
Vol 93 (3) ◽  
pp. 608-618 ◽  
Author(s):  
E. J. Weerman ◽  
J. Van Belzen ◽  
M. Rietkerk ◽  
S. Temmerman ◽  
S. Kéfi ◽  
...  
1994 ◽  
Vol 49 (9) ◽  
pp. 856-860
Author(s):  
Barbara Drossel ◽  
Siegfried Clar ◽  
Franz Schwabl

Abstract We modify the rules of the self-organized critical forest-fire model in one dimension by allowing the fire to jum p over holes of ≤ k sites. An analytic calculation shows that not only the size distribution of forest clusters but also the size distribution of fires is characterized by the same critical exponent as in the nearest-neighbor model, i.e. the critical behavior of the model is universal. Computer simulations confirm the analytic results.


Evolution ◽  
2010 ◽  
Vol 65 (2) ◽  
pp. 490-500 ◽  
Author(s):  
François Massol ◽  
Anne Duputié ◽  
Patrice David ◽  
Philippe Jarne

2014 ◽  
Vol 142 (10) ◽  
pp. 3830-3846 ◽  
Author(s):  
Malte Rieck ◽  
Cathy Hohenegger ◽  
Chiel C. van Heerwaarden

Abstract This study analyzes the effects of land surface heterogeneities at various horizontal scales on the transition from shallow to deep convection and on the cloud size distribution. An idealized case of midlatitude summertime convection is simulated by means of large-eddy simulations coupled to an interactive land surface. The transition is accelerated over heterogeneous surfaces. The simulation with an intermediate patch size of 12.8 km exhibits the fastest transition with a transition time two-thirds that over a homogeneous surface. A similar timing is observed for the precipitation onset whereas the total accumulated rainfall tends to increase with patch size. The cloud size distribution can be approximated by a power law with a scale break. The exponent of the power law is independent of the heterogeneity scale, implying a similar cloud cover between the simulations. In contrast, the scale break varies with patch size. The size of the largest clouds does not scale with the boundary layer height, although their maximum size scales with the patch size. Finally, the idea that larger clouds grow faster, known from homogeneous surface conditions, is not fully valid over heterogeneous surfaces. These various aspects can be understood from the complex interplay between the characteristics of the triggered mesoscale circulations and a cloud development acting in response to the diurnal cycle in surface heating. The results also call for adequate representation of such effects in convective parameterizations.


2020 ◽  
Author(s):  
Kathrin Holenstein ◽  
Eric Harvey ◽  
Florian Altermatt

AbstractBiological invasions are globally affecting ecosystems, causing local species loss and altering ecosystem functioning. Understanding the success and unfolding of such biological invasions is thus of high priority. Both local properties and the spatial network structure have been shown to be determinants of invasion success, and the identification of spatial invasion hubs directly promoting invasion dynamics is gaining attention. Spatial dynamics, however, could also indirectly alter invasion success by shaping local community structure: in many ecosystems, such as riverine networks, regional properties such as patch size distribution are known drivers of local community structures, which themselves may affect the establishment success of invading species. Using microcosm experiments in dendritic networks, we disentangled how patch size distribution and dispersal along specific network topologies shaped local communities, and, subsequently, affected the establishment success of invading species. We find that inherent patch size distributions shaped composition and diversity of local communities, and, subsequently, modulated invasion success. Specifically, the relationship between local diversity and invasion success changed across an increasing patch size gradient from a negative to a positive correlation, while overall increasing patch size reduced invasion success. Connectivity did not have a direct effect on invasion success but indirectly affected invasions by shaping diversity patterns in the whole network. Our results emphasize the relevance of indirect, landscape-level effects on species invasions, which need to be considered in the management of spatial habitat networks.


2013 ◽  
Vol 33 ◽  
pp. 84-87 ◽  
Author(s):  
J. Fornell ◽  
N.T.C. Oliveira ◽  
E. Pellicer ◽  
N. Van Steenberge ◽  
M.D. Baró ◽  
...  

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