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Administrative: Important Birding Areas (IBAs)
IBA Identification Criteria
The site identification criteria was patterned after the approach taken by BirdLife International. As the IBA Program evolved, it began to take on a more hierarchical approach such that IBAs can be significant at the state, continental, or global level. The importance of all IBAs will eventually be ranked according to their global, continental, or regional significance. For example, a site that contains 100 breeding pairs of a colonial waterbird species might trigger a state-level IBA. Generally, sites that contain at least 1% of a flyway or sub-species population may trigger a continental IBA and those that support at least 1% of the global or biogeographic population of this species would trigger a global IBA (for complete details on the global and continental IBA criteria see http://www.audubon.org/bird/iba/criteria.html). The thresholds at the continental and global levels were set and standardized by the U.S. IBA Technical Committee. The thresholds at the state-level, however, are not nationally standardized and are instead established by the State IBA Technical Committees. This approach allows states the freedom to develop meaningful thresholds that can adequately address the specific habitats and conservation needs of their state’s bird species.
In Virginia, the IBA Technical Committee established thresholds that would generally capture approximately the top 10% of habitats for a particular bird species or assemblage of species in Virginia. This often meant stepping down the Global and Continental thresholds to reflect state level populations. For example, the Continental threshold for Loggerhead Shrikes is over 100 breeding pairs. In Virginia, where the Loggerhead Shrike is rare, locations that support at least 2 consistent breeding pairs could qualify as a state-level IBA. In other cases, setting state-level thresholds meant increasing the thresholds set at the Continental or Global levels to better reflect Virginia populations. One example of this is the Bald Eagle. This species, assessed from a continental perspective, is relatively uncommon. However, the Virginia Bald Eagle population is thriving and eagles are quite common and densely concentrated along coastal waterways. In this case, in order to capture the top 10% of Bald Eagle sites in Virginia, the state-level breeding threshold had to be set higher than that of the continental threshold.
IBA Scale
The Virginia approach to IBA identification often led to relatively large landscape-scale IBAs of high-quality habitat rather than smaller IBAs defined by jurisdictional boundaries. In most cases, IBAs encompassed one or more tracts of land under conservation ownership as well as many privately or municipally owned tracts. These landscape-scale IBAs are both meaningful from an ecological perspective and useful from a conservation perspective.
From an ecological perspective, such IBAs encompass functioning systems whose boundaries are defined by the distribution and abundance of habitat and thus bird populations. Entire guilds or communities of birds were often evaluated when deciding on final IBA boundaries rather than just one high-priority ‘trigger’ species. This allowed us to assess the value of each landscape for the long-term population viability of sensitive species. For instance, boundary decisions were often influenced by the type and value of ecological services provided, the amount of habitat needed to accommodate shifts in distribution or population expansion of priority species, or the extent of habitat diversity needed to maintain stability in the system rather than simply the current distribution of birds on the landscape. This approach is particularly valuable for dynamic systems such as barrier island habitats or successional landscapes, where the amount, type, and quality of habitats are constantly shifting. Jurisdictional boundaries were used only when they corresponded with habitat extent such that discreet habitat boundaries also defined a managed system.
Perhaps the greatest benefit of identifying landscape IBAs is that such landscapes invariably encompass lands under multiple conservation ownership as well as unmanaged or privately owned properties. Far from being a burden, diverse inclusion across ownership boundaries has the greatest potential for long-term conservation by providing a unifying framework in which each organization can fit. Landowners and managers can focus on larger conservation goals for the entire system while working to achieve these goals through individual projects within their planning areas. IBAs that extend beyond political boundaries also provide meaningful acquisition boundaries for land trusts and conservation groups to strategically target land protection efforts where they will have the maximum benefit to bird populations.
We aim to focus our primary conservation efforts on areas within the larger landscape that can most effectively advance conservation of the entire IBA. Thus, for each of the larger IBAs, we have identified and highlighted critical management or conservation units on each IBA map. These units have the greatest potential to contribute to long-term bird conservation within the IBA either because they are already protected or managed for conservation or because they support significant populations of priority bird species. Although units are most often jurisdictionally defined parcels, they can also include large tracts of private lands or smaller tracts within protected areas that support core populations of sensitive species. We have been, and will continue to, accomplish conservation by working with land owners and managers on these units to craft conservation projects that better address the needs of priority species in the context of the larger IBA. As a secondary focus, we will seize opportunities to improve or further protect habitats on unprotected lands adjacent to or connecting focal units through acquisition, advocacy, or landowner incentive programs like those under the Farm Bill. Together these projects will advance the larger system toward a common conservation goal - one that will ultimately benefit not just the species present on a particular management unit, but rather all priority species in the system.
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