摘要：
Aims The pine rocklands of southern Florida are a fire-dependent forest associated with outcrops of limestone. Pine rockland plants have several adaptations to fire, and for many species, burning increases plant growth, flowering and seedling establishment. The pine rockland forest has been reduced and fragmented in recent decades. Outside of Everglades National Park, only 2% of the original pine rocklands remain, and they are in the form of small fragments. Our objective is to investigate the effects of fragmentation and habitat quality on abundance and plant reproductive fitness of Angadenia berteroi (A.D.C.) Miers, a threatened species of the southern Florida pine rockland.
Methods We estimated the density of plants using a stratified random sampling design, and reproductive fitness (in terms of percentage of plants with flowers and fruit) by walking transects in an array of habitat fragments of different sizes and degrees of isolation (distance to the nearest fragment) as well as in continuous habitat. Structural equation modeling (SEM) was employed to investigate how A. berteroi reproductive fitness was affected by fragmentation and habitat quality.
Important findings Habitat fragment size was correlated with the density of A. berteroi, but did not have a great impact on its reproductive success. However, habitat quality represented by litter depth and subcanopy cover had strong negative effects on the reproductive fitness of A. berteroi, suggesting that increased light availability and low litter cover resulting from recent fires may favor reproduction.
