Ecological relationships among eastern cottontail rabbits, tall fescue, and native warm-season grasses.

摘要

Tall fescue (Festuca arundinacea) grasslands may not provide suitable habitat for many wildlife species. Also, most fescue contains an endophytic fungus (Neotyphodium coenophialum) associated with nutritional and reproductive problems in livestock and laboratory mammals. The objectives of my research were (1) to determine the effects of the tall fescue endophyte on nutrition and reproduction in the free-ranging eastern cottontail (Sylvilagus floridanus) rabbit and (2) to develop effective methods of converting tall fescue grasslands to native warm-season grasslands. Eastern cottontails (n = 111) were collected during the 1998 breeding season (May–August) from both tall fescue and non-fescue grasslands habitats. Sex, age, Condition Index, Kidney Fat Index, and paired adrenal weights were determined for each rabbit. Paired testes and epididymal weights in males, and a variety of physiological reproductive parameters in females were also assessed. In fall 1998, plant communities were described by sampling 30 1-m2 plots in each grassland where a rabbit was collected. Also, >30 tall fescue plants from each site were collected and analyzed for the presence of the endophyte. Tall fescue cover (%) and tall fescue endophyte infection levels were used to classify cottontail collection points as tall fescue or non-fescue habitats. Tall fescue habitats were dominated by fescue (x¯ = 83% cover) that was highly endophyte-infected (x¯ = 92% infection rate), whereas non-fescue grassland habitats generally lacked tall fescue (x¯ = 6% cover) and were relatively uninfected (x¯ = 1% infection rate) by the tall fescue endophyte. Body condition (nutritional) and reproductive parameters of male and female cottontails collected from endophyte-infected tall fescue grasslands and non-fescue grassland habitats were similar. My results suggest that under natural conditions, the tall fescue endophyte is not negatively influencing the nutritional ecology or reproductive potential of free-ranging eastern cottontail rabbits in Kentucky.; Conservation of tall fescue to native warm-season grasses can be accomplished by two methods. The first method includes a spring burn, followed by a pre-emergence application of imazapic, and no-till seeding native warm-season grasses. The second method involves conventional tillage and includes preparing a firm seedbed, seeding native warm-season grasses, and applying imazapic at the time of seeding. Both methods consistently resulted in established stands of native warm-season grasses in one growing season.