The Dissemination of Prickly Pear Seed by Jack Rabbits¹

Abstract

DECENT experiments at the Fort Hays Branch of the Kansas f'.. Agricultural Experiment Station indicate that jack rabbits are important agents in disseminating the seed of prickly pear cactus. It may be responsible for much of the rapid spread of this weedy plant over the range lands in western Kansas and possibly in other sections of the Great Plains and Southwest in recent years. The increased attention now being given to the control of prickly pear encourages consideration of this me~hod of spreading the seed.Dameron and Smith (1) 3 estimated that the area in Texas infested with prickly pear (Opuntia spp.) comprises at least 6o million acres but stated that it is only during recent years that the plant has become sufficiently abundant to give concern to livestock men. Nearly 4 million acres of pasture land in Kansas are infested with prickly pear according to a survey made by. Yost (8) in 1939. The importance of rabbits and other animals as agencies in the spread of prickly pear (Opuntia spp.) was recognized in Australia (2) in 1919. Most of the seeds found in rabbit droppings were chewed into small bits but occasionally whole seeds were observed. The emu and the black magpie were considered of much more importance in the spread of prickly pear since they ate large quantities of the ripened fruit and the seed passed uninjured through their digestive tracts and was scattered by them over wide areas. Large quantities of seed were also found in the droppings of cattle.Toit (3) and Phillips (4) reported that in South Afric(!. the fruit of prickly pear (Opu_ntia spp.) furnishes an important item in the diet of native tribesmen and that~~~ed of increased viability is thus disseminated over wide areas. Monkeys, babdo~s, goats, and. various kinds of birds were also reported to play important rol~~:~ disseminating the seed. Cattle were observed to eat ripened prickly pear frtiits·ayidly, often acquiring such a craving for them that they would eat prac-ticaitY~othing else during the fruiting season.At Hays, Kans., the activities of jack rabbits in feeding upon ripened fruit and in disseminating seed of prickly pear were observed (7) by chance in August 1939 during the course of some cactus eradication experiments. Following this observation, rather careful studies were made to determine the nature and extent of the seed dissemination. Germination tests of seed recovered from rabbit droppings and from the dried fruits were made to determine the effect upon viability of passage through the digestive tract of the jack rabbit.

Seasonal changes in the diet of the European rabbit (Oryctolagus cuniculus) from three different Mediterranean habitats in south-western Australia

“…Seed comprised 13-16% of the diet of rabbits during summer in semi-arid Western Australia (Robley et al 2001), and European rabbits are also known to consume flowers and seed heads, and impact on the biomass of several forbs in subalpine New South Wales , and grasses in the UK (Watkinson and Harper 1978). American jackrabbits (Lepus californicus) have been implicated in the spread of prickly pear (Timmons 1942), and European rabbits can affect pasture establishment immediately after seeding in Europe (Phillips 1953). Rabbits are also implicated in the dispersal of Retama monosperma seed in coastal sand dunes in Spain (Dellafiore et al 2006).…”

Reproductive biology of Opuntia: A review

“…Only seeds damaged by mastication (85%) were found in the pig (Mandujano et al, 1997), which could be indicative of a poor role for peccaries (Peccary tajacu) as dispersers. The jackrabbit (Lepus californica) consumes O. macrorhiza fruits (Timmons, 1941) and the eastern cottontail (Sylvilagus floridanus) O. compressa fruits (Baskin and Baskin, 1977). There are several small mammal species, including Chaetodipus penicillatus, Dipodomys merriami, D. nelsoni, Perognathus flavus, Peromyscus eremicus and Spermophilus spilosoma that play a minor role in the consumption of Opuntia fruits (Montiel and Montan˜a, 2000).…”

The Role of Some Birds and Mammals in Seed Germination

“…Because of this beneficiul effect, acacia seed from goat and sheep pens is said to be used extensively in nursery sowings in India. Timmons (1942) working with prickly pear seed in Kansas found the germination of seeds recovered from the pellets of wild jack rabbits to be 50 percent higher than the controls. Subsequent studies by Brown (1947) in this same area not only confirmed Timmons' findings, but also showed that these animals as well as cottontails may have a beneficia!…”