Dynamics of porcupine {hystrixindica kerr) diggings: Their role in the survival and renewal of geophytes and hemicryptophytes in the negev desert highlands

Porcupines dig as deep as 25-30 cm to obtain corms, bulbs, tubers, and underground parts of leaves and stems that they consume as food. Eighteen species of geophytes and hemicryptophytes were found to be consumed by porcupines in the Negev Desert highlands. Another 10 species inhabit these diggings, but they are not known to be consumed. Porcupine diggings in the Negev Desert were found to be important microhabitats in which runoff water and organic matter accumulate, improving conditions for germination, seedling establishment, and plant growth. The dynamics of the “recovery” of porcupine diggings (the rate of their covering) depends on topography, geomorphology, vegetation, and on the plant species inhabiting them. It is possible to differentiate among 3 patterns of “recovery” occurring in various localities: (1) porcupine diggings covered as a result of flooding as soon as the next rain comes; (2) diggings which may remain uncovered for more than 20 years; (3) an intermediate group of diggings which remain uncovered for about 5-10 years. The latter are mainly inhabited by perennials, which renew themselves in the digging after being partially consumed. The plants are reconsumed by porcupines every few years, which results in the renewal of the digging. In this system, it is possible that a certain degree of mutualism exists between the porcupine and the plants. The importance of porcupine diggings for vegetation renewal by germination or by vegetative propagation and the changes occurring in the diggings in the course of time are discussed.