How ELUs Can Guide Conservation





4. ELUs as a Planning Tool -- Identifying Conservation Priorities

ELUs Assist Conservation Planners
ELUs are a tool to help resource managers and conservationists achieve important goals for land protection: to preserve diversity, and to preserve representative assemblages of plants and animals. It is important to note that ELUs are but one of many factors conservationists might consider in choosing properties to protect. Aesthetic and cultural values, water resource protection, public access, etc. are criteria that might be considered along with ELUs.

ELU Diversity Maps
To preserve diversity, we mapped how many kinds of ELUs there are within 1,500 feet (30 pixels) of every location in RI.  The values range from 1 ELU in the 1,500 foot radius to a maximum diversity of 65 different ELUs.  Large contiguous areas of high ELU variety would be desirable conservation targets because they are likely to support many different kinds of plant communities.  A map of the different ELUs in a portion of South Kingstown is shown here and a map of the variety (diversity) of ELUs in the same area is also shown.

Identifying Unprotected ELUs
Protecting plants and animals that are representative of the region is another important conservation goal.  ELU’s can provide insight into these targets too.  We calculated the total proportion of land occupied by each of the 20 dominant ELUs in Rhode Island.  We also computed the variety of ELUs in lands that have been protected (e.g., by the towns, the state, federal agencies, NGO’s such as the TNC and the Audubon Society, and local land trusts).  By comparing the extent of an ELU in the state by how much is protected, we can identify ELU classes that are not well-represented in our portfolio of protected lands.  These underrepresented ELUs might be good targets for future land acquisitions.  A map of underrepresented ELUs in an area in the Matunuck Hills of South Kingstown is presented here.

How To Use ELUs
So how can conservation planners use ELUs in their assessment of potential lands to conserve? Here are some simple guidelines:

  • The map of the variety of ELUs is an important planning tool. Where you have many different kinds of ELUs in an area, you have the possibility of finding many different plant and animal communities now and in the future. If the conservation goal is to protect biodiversity, these are high value sites. We have aggregated the ELU variety classes into a small number of categories (* see note below) to guide conservation planners. The most diverse areas of RI have 48 or more different ELU types in a 1,500 foot radius. Only 1 percent of the state is in this class. The next most diverse areas of the state (6.6% total land area) have 39 to 47 different ELU types in a 1,500 footradius. This is followed by diverse areas (23.1% of RI land surface) of 29 to 38 kinds of ELUs in a 1,500 foot radius.
  • The map of underrepresented ELUs is a helpful guide if the conservation goal is to make sure that RI's most common ecosystems are adequately protected. The objective here would be to protected areas that are known to contain underrepresented ELUs.

* These classes are defined by how many standard deviations from the state mean ELU variety they are. The most diverse class is 3 or more SD units greater than the state mean variety (24 kinds of ELUs within 1,500 feet). The next most diverse class is 2 - 3 SD units followed by 1 - 2 SD units. We have chosen this method of aggregating ELU variety classes because it is objective and statistically-based.

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