Shrublands and grasslands are widespread in dry lowland areas and some moist upland areas of the USVI, especially on St. Croix and cays, and provide an important resource for wildlife despite being greatly altered by the activities of humans and livestock. Fewer species of wildlife occur in shrublands and grasslands than in forest because of the lower diversity of plant species and simpler vegetative structure, although common species such as the Zenaida Dove (Zenaida aurita) may be abundant. Shrublands and grasslands can be thought of as a transitional stage as land becomes naturally reforested after agriculture or other land clearing. As species diversity and structure increase, so does the quality of wildlife habitat. The key to managing shrublands is to prevent fire, grazing and other disturbances so succession can continue unimpeded. Shrubland and grassland formations are highly variable. Although several types of formations can be recognized, they grade into one another and are generally difficult to delineate.
Shrublands and herbaceous plant communities provide a range of ecological services, including wildlife habitat, though to a lesser extent than more mature plant communities (Lugo and Helmer 2004). Shrublands and secondary forests are able to regain much of their structure and species diversity in a matter of decades. The vegetation controls erosion and provides some generalist habitat to wildlife. Undisturbed coastal areas, steep slopes and other sites that experience extreme conditions may remain as shrublands indefinitely. Shrublands on cays provide critical nesting habitat for migratory seabirds, columbids, and other ground nesting birds.
The extensive development of coastal and low elevation areas has displaced, degraded, or fragmented large areas of shrublands, resulting in increased surface temperatures, increased erosion of soils, and increased sedimentation and eutrophication of wetlands and inshore marine habitats. The effects of vegetation removal, degradation, and fragmentation of shrublands on wildlife include decreased carrying capacity for wildlife populations, decreased dispersal and gene flow among fragmented populations, decreased genetic variability, increased genetic inbreeding, decreased effective population sizes, and increased risk of local extirpations. Wildfires, especially on St. Croix, pose an increasing threat to these habitats under drought conditions, which are becoming more intense and prolonged.