Habitat Use, Distribution and Conservation Status of the Mikado Pheasant (Syrmaticus mikado) in Taiwan

To evaluate the conservation status of Taiwan’s mikado pheasant, Syrmaticus mikado (Phasianidae), I test the similarity of preferred habitat to primary and secondary forest, develop models of habitat availability within Taiwan, and examine population trends within two locations inside Yushan National Park. The characteristics of locations with pheasant activity were most similar to secondary forest: high shrub stem counts and low canopy and leaf litter coverage. None of these variables were applicable to geographic informationsystems analysis. To the known extent of range and area of occupancy, I compared a model based on the habitats described in field guides. This model underestimated extent of range, confirmed that 39% of the pheasant’s range is protected inside parks and reserves, and suggest that Taiwan potentially has 6477 km2 of habitat available to S. mikado. Within Yushan National Park, there may be as many as 10,000 S. mikado. The small home ranges (\u3c0.86 km2) and the lack of movement across the 400 m separating the study sites imply limited gene flow between populations and poor ability to colonize suitable habitat. There were 58 pheasants per km2 in the primary forest site and 48 in the secondary forest site. At the primary forest site, the population appeared stable. At the secondary forest site, the population declined 65% from 3.56 pheasants encountered per day in 1989-1992 to 1.24 in 1996-1999 due to poor productivity because of increased numbers of nest predators (from 1.4 predators per day to 2.2) and the cooler weather conditions during hatching. In 1989-1991, most rainfall was in the last week of June, but rainfall was evenly distributed throughout May and June of 1996-1998. Poaching, a threat to adult pheasants, increased during this time from 0.06 incidents per day to 0.23. As the pheasant lives at elevations naturally disturbed by landslides, tolerance for disturbance would be adaptive. Because of the poaching, the limited nature of the pheasant’s distribution, and until the population decline is identified as indicating a general trend or part of a cyclic pattern in the pheasant’s population dynamics, I recommend S. mikado be considered vulnerable to the risks of extinction

Frequency-Dependent Seed Dispersal by Ants of Two Deciduous Forest Herbs

Two co—occurring deciduous forest myrmecochores, Asarum canadense and Jeffersonia diphylla, release their seeds at approximately the same time, and therefore potentially compete for ants as dispersers. Within a single woodlot, we placed seeds of both species inside a dense Jeffersonia population away from Asarum plants, inside a dense Asarum population away from Jeffersonia plants, and in a site where plants of neither species occurred. No preference was exhibited by ants where natural populations were absent. Preference at the other two sites was frequency dependent: ants preferred seeds of the introduced species. Species preferred by ants have higher seed and seedling survival because by being carried into ant nests they escape predation and avoid nutrient deficiency. Implications of frequency—dependent dispersal are discussed