Why do we need stewardship?
California is biologically rich, but many of the state’s natural habitats face threats. California has been designated a biodiversity hotspot, which means that it is a place where exceptional concentrations of endemic (“native to or confined to a certain region”) species are undergoing exceptional losses of habitat. These losses occur in two ways:
- Conversion: the change of natural habitat into developed or agricultural areas.
- Degradation: losses which involve changes in the structure, function, or composition of an ecosystem. At some level of degradation, an ecosystem ceases to be natural.
Losses have been significant. California native grasslands have been reduced to about one percent of their original extent, both through land conversion and degradation by exotic species invasions. Other seriously threatened ecosystems include wetlands and riparian woodlands, which have been reduced to 10 percent or less of their original area. Many of the animal species dependent on these habitats have declined as well.
Like California, the Elkhorn Slough watershed is rich with diverse habitats and animals. However, the watershed also faces many of the threats. For example, many of the Elkhorn Slough Reserve’s grassland and oak woodland understories are highly invaded by exotic plants; its freshwater springs have been almost entirely lost due to groundwater overdraft; and 75% of its historical salt marshes have been lost through conversion.
In order to preserve the important natural habitats that remain, the Elkhorn Slough Reserve’s stewardship program gives high priority to habitat protection within Reserve boundaries. In areas already degraded by past land uses, invasive species, or pollution, the stewardship program endeavors to sustainably restore at least some of the lost aspects of local biodiversity and natural processes.
