Predators pressure

Can land and wildlife managers use it in assessing predator pressure ... 

Van Damme, R. and Castilla, A. M. (1996). Chemosensory predator recognition in the lizard Podanis hispania effects of predation pressure relaxation. Journal of Chemical Ecology 11,13-22. 

Bertness, M. D., Garrity, S. D., and Levings, S. C., Predation pressure and gastropod foraging a tropical-temperate comparison, Evolution, 35, 995, 1981. 

FIGURE 9.2 Different allocation patterns predicted to be adaptive along environmental gradients of abiotic stresses, competition, and predation pressures, which should select for high resource allocation to maintenance, resource acquisition, and defense, respectively. This model predicts allocation patterns for Grime s plant strategies13 and draws predictions from various chemical defense theories. Allocation to reproduction and growth are not shown for clarity. 

Avoiding consumption involves being where and/or when consumers are rare or inactive. Seaweeds and sessile invertebrates can avoid predators spatially, by growing in habitats with low densities of predators, such as reef flats, sand plains, sea grass beds, and mangroves,20-23 or temporally, by growing when predation pressures are low.24-26... 

Brooks, M. T., Hood, R. R., and Kemp, W. M. (2005). Nonlinear interactions between predation pressure and nutrient inputs in simulated estuarine food-webs. Mar. Ecol Prog. Ser. (draft manuscript). 

FIGURE 18.12 Predation pressure (C/P—sprat population consumption per copepod production) by sprat on the copepods Pseudocalanus acuspes (blackbars) and Temora longicornis (grey bars) data are from Mollmann and Koster, 2002. 

The laboratory and field experiments include both short- and long-tenn experiments. Examples of short-term experiments include tests to investigate the genninative capacity of seeds in substrate and standard laboratory experiments to measure the toxicity of the surface water (bioassays). Long-tenn experiments include compartmentalisation (enclosure) of a water body to prevent predation pressure from fish and the use of mesocosms (model ecosystem to scale) to assess the influence of tides on reed growth. 

Another prediction drawn from the present model is the decrease in the optimal P ax with the increment of r Plants would have lower photosynthetic capacity in habitats where the environmental constraints make the leaf cost higher. Nutrient deficiencies, drought, and high predation pressure can increase the cost to construct and maintain a leaf (27,32,33) The low photosynthetic capacities found in plants growing under nutrient-poor conditions (27,33) agree with the above prediction. For detailed discussion using this model, see (30). 

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