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A new model for vegetation patterns is introduced. The model reproduces a wide range of patterns observed in water-limited regions, including drifting bands, spots, and labyrinths. It predicts transitions from bare soil at low precipitation to homogeneous vegetation at high precipitation, through intermediate states of spot, stripe, and hole patterns. It(More)
A mathematical model for plant communities in water-limited systems is introduced and applied to a mixed woody-herbaceous community. Two feedbacks between biomass and water are found to be of crucial importance for understanding woody-herbaceous interactions: water uptake by plants' roots and increased water infiltration at vegetation patches. The former(More)
Habitat and species richness in drylands are affected by the dynamics of a few key species, termed "ecosystem engineers." These species modulate the landscape and redistribute the water resources so as to allow the introduction of other species. A mathematical model is developed for a pair of ecosystem engineers commonly found in drylands: plants forming(More)
We examine the role of the sit and wait foraging strategy and of the stability and predictability of the biotic environment in shaping population biology and life history traits of the desert scorpion, Scorpio maurus palmatus. The study was carried out in a loessial plain in the Negev desert, Israel. We used a grid system (5x80 m) within the Hammada(More)
The Mediterranean landscape is characterized by a heterogeneous structure: a mosaic of woody plants (trees or shrubs) with scattered patches of herbaceous vegetation. Although the herbaceous and woody patches are adjacent to each other, plant species composition in them is substantially different. This could be attributed to either differences in(More)
Recent studies demonstrate positive density-dependent feedbacks between animal populations and their resource supply that result in increased individual fitness at high densities. Such feedbacks occur in both terrestrial and aquatic organisms not showing strong social organization. A number of different mechanisms are involved. Detecting positive feedbacks(More)
We explore the demographic consequences of site selection by animals on their abundance among habitats. We found that pre and post settling survivorship are important links between the behavioral decisions where to settle and the distribution of a population among habitats. This was demonstrated for 10 generations of the desert isopod, Hemilepistus(More)
Understanding biotic influences on soil processes is a major research frontier made challenging by organismal diversity, variation in distribution, and variety of interactions. Nevertheless, two fundamental influences can be recognized: assimilation/ dissimilation (uptake, metabolism, wastes, death) and physical ecosystem engineering(More)
Woody vegetation, as an ecosystem engineer, can modulate the landscape such that the levels of resources in its vicinity undergo positive and negative changes as far as the herbaceous vegetation is concerned. To better understand how these processes play out in a semi-arid ecosystem, we examined resource modulation by woody vegetation, and the response of(More)