Report of the AOU Conservation Committee on the Partners in Flight Species Prioritization Plan

Partners in Flight (PIF) is a coalition of federal, state, and local government agencies; nongovernmental organizations (NGOs); philanthropic foundations; and industry that is working to conserve the birds of the Western Hemisphere. PIF was launched in 1990 in response to growing concerns about declines in the populations of many landbirds, and to spearhead the conservation of birds not covered by existing initiatives, such as the North America Waterfowl Management Plan. The initial focus of PIF was on Neotropical migrants (species that breed in North America north of the tropics and winter in Central America and/or South America). The emphasis has expanded to include most landbirds and other marine and aquatic species that require terrestrial habitats. PIF is coordinated in the United States by four regional working groups (Northeast, Southeast, Midwest, and West) and five technical working groups (Research, Monitoring, International, Communications, and Education) that represent participating agencies of state governments, the federal government, a variety of NGOs, and private industry. PIF is developing a Bird Conservation Strategy designed to conserve the birds of North America and their habitats before they become endangered. PIF Bird Conservation Plans seek to restore, maintain, and protect bird populations and habitats by setting conservation priorities and objectives in each state and physiographic area in the United States and by outlining strategies for implementation. Bird Conservation Plans build on the successes of earlier conservation initiatives including international treaties, the North American Waterfowl Management Plan, and the Western Hemisphere Shorebird Reserve Network. A basic tenet of the strategy is that habitats that support the most threatened species are most in need of conservation. Central to the task of determining which habitats need to be conserved is a ranking scheme to prioritize the relative risk of extinction among species. PIF has developed a process for ranking bird conservation priorities and has begun to apply it to several geographic areas (Hunter et al. 1993). Ranking schemes have long been used to evaluate conservation priorities (Millsap et al. 1990, Master 1991, Reed 1992). The National Audubon Society developed lists to prioritize the conservation status of North American birds through the periodic publication of its “Blue List” and “Watchlist” over the past 25 years (Anonymous 1971, Arbib 1976, Muehter 1998). Natural Heritage Programs in each state publish state conservation rankings for birds and other taxa, and national lists are also produced. The American Ornithologists' Union (AOU) was formally requested by PIF and the National Audubon Society to review the PIF prioritization plan (see preceding publication by Carter et al.). A special committee (hereafter, “the Committee”) was formed under the auspices of the AOU Conservation Committee and was approved by AOU Council to complete the task. This report summarizes the Committee's deliberations and recommendations. The Committee defined its task to answer three central questions: (1) Is a prioritization process needed for conserving birds in North America? (2) Is the process proposed by PIF reasonable and scientifically sound? (3) How should the results of the process be interpreted for the purpose of conservation planning? Birds contribute to ecosystem health and provide economic, recreational, scientific, and aesthetic value for society. In recent decades, however, dozens of bird species have been federally listed as threatened or endangered due to alarming population declines and range retractions resulting from human-induced factors such as habitat loss and degradation, pesticides, cowbird parasitism, and invasion by nonnative plant and animal species (Collar et al. 1994, Flather et al. 1998, Wilcove et al. 1998). Saving species that are near extinction can be difficult, costly, and politically charged. PIF seeks to develop a plan to conserve bird species of North America. Unlike most conservation plans, which deal with few species that have relatively high risks of extinction, most of the hundreds of species included in the PIF plan are not in imminent danger and have a low risk of extinction in the near future. Most species have large geographical ranges, huge global populations, and use many habitats on their breeding and their winter ranges. However, focusing attention on bird species before they become endangered shifts the conservation agenda from reactive, last-minute rescue attempts to proactive, preventive actions to keep common birds common. An important outcome of such an approach is to preserve the diverse roles that birds play in ecosystem function, for example as agents of insect control that reduce the likelihood of pest outbreaks, or as seed dispersers that help regenerate forests (Howe 1986, Kirk et al. 1996). The Committee believes that keeping uncommon species from becoming endangered and preventing common species from becoming uncommon is an important conservation goal. Bird conservation priorities must be developed so that limited human and financial resources can be directed efficiently and productively toward those species and habitats that are most in need. Despite large population sizes and ranges, some “common” species are clearly more vulnerable to population declines than are others because of smaller geographic ranges, smaller population sizes, and greater habitat specialization (Pimm et al. 1988). Similarly, some ecoregions (e.g. Mississippi Alluvial Valley, Northern Tallgrass) and habitats (e.g. western riparian forest, California coastal scrub) face serious threats as a result of conversion of native vegetation to human land uses. Without some sort of prioritization scheme, it will be difficult to focus limited resources on species, ecoregions, and habitats that are in need of conservation. In the absence of a prioritization scheme, bird conservation plans would be hampered by the overwhelming number of species to be considered simultaneously, with each species possibly having different management needs. Arguably, any management action could be criticized because it would inevitably cause declines of some species, or justified because there would always be some species that would benefit. Attempts to use diversity indices or guild-based characterizations for evaluating management options have failed because they often miss important changes in populations of rare species that should be a higher conservation priority. By ranking species and periodically reevaluating those rankings, we potentially can simplify conservation planning for multiple species by focusing on a subset of the species within a state, region, or country. Thus, ranking can enable implementation of conservation plans over a variety of scales and provides greater flexibility to meet multiple objectives. The Committee concludes that a thoughtfully constructed process that ranks the relative susceptibility of birds to extinction and large-scale declines can play a useful and important role in conservation efforts if it is periodically evaluated and continually improved. Several approaches have been developed to prioritize species for conservation. In general, they are based on the premise that the highest priority species (1) are most at risk of extinction, local extirpation, or are experiencing large population declines; or (2) represent the most unique evolutionary lineage. However, priorities might also be set by cultural values (Millsap et al. 1990, Norton 1994) or for Reed different for susceptibility to for conservation The that species based on such as population population and geographic range et al. 1986, Reed 1992). and et al. and Reed developed schemes that are values to different and to risk a can also be in a of risk and Norton 1993). that of extinction, et al. or population and require large of and are not for long lists of species. of could be used to develop of risk for species, than a of as was by (Collar et al. 1994) and The Conservation priorities have also been proposed based on that species by greater value on unique species, such as the of a et al. 1991, et al. is of several that the United States and to priorities Partners in Flight developed an that provides a for setting conservation priorities by and physiographic areas of North America et al. The PIF prioritization priority to based on global and local priority The are to relative risk of extinction also include an of the relative of a to conservation efforts within the global a breeding and and a state and physiographic area a local population local threats on the breeding and and the of an area to a species. is from to with the highest conservation priority and the Thus, the can range from to greater conservation are and approved by the PIF and state and physiographic area are and approved by the PIF and The PIF ranking scheme also has for in the global and local priority (e.g. et al. 1993). PIF in with the population priority et al. The Committee believes that a prioritization scheme to local and global and we the of Conservation planning at and and species can be conservation in some and would have a low conservation priority in the United they are of western riparian ecosystem which from state to state (Hunter et al. the is in in many of the and the PIF prioritization process is reasonable and scientifically the Committee developed a of four about the and evaluated their The PIF ranking process has been developed for the birds of North America. their PIF defined North America to include the and from through and the of the et al. The Committee believes that developing a ranking scheme for species within the United States is a the of for most species, and an of PIF and will the of also is the likelihood of the is that the is developing a different prioritization et al. there is value in of the status for the birds in different and should cause efforts to the PIF ranking scheme of the United States in the Committee's more The of Central America and the is with more of the for the ranking is for most species relative population area resulting in high of from any ranking it is if the ranking scheme would be or by of Central America or the to the of in the an initial prioritization scheme based on limited of the species, such as the bird areas developed by International, be more However, if PIF can it is reasonable to apply a of their prioritization scheme to the birds of Central America and the of their support many of the species that PIF has in the United PIF has a in migrants on the and is with the PIF scheme is Central America and the the Committee believes it will the high risks to many birds in relative to North American species in the United many species that or of Central and many will high (Collar et al. The PIF prioritization scheme is to bird species within the of et al. The Committee believes that ranking species is a it that and species be because their populations and their relative risks of extinction are not conservation species, as as those that have been to a area in North should not be conservation species should be a of or in a unique that might management that would be to the species. The PIF ranking scheme should a to its and that and species have conservation some species have become conservation for native species (e.g. a based on the risk of extinction for is not the Committee that native species that have expanded their on their such as the Northern and the Northern be in the ranking The Committee that included in the PIF prioritization scheme are important and for ranking the susceptibility of birds in the United This an by the PIF and the Committee in developing However, the Committee that PIF the prioritization scheme a few to some of the and more range become they should be rankings of the and range are based on of geographic range based on breeding bird the to which large areas within a range are not by the species (e.g. and potentially the of some and the of Similarly, range that can help focus regional conservation efforts on species. range species at greater risk of winter habitat loss than such as the which in a of might be useful for to and and habitats often are so birds in a few a should help conservation efforts at potentially important will be difficult to evaluate for most terrestrial species. The to and to are the most and potentially are the and the most of the and would help it be useful to the focus on past threats and are toward habitat habitat loss is the most cause of species declines et al. 1998, Wilcove et al. more should be to other threats could be The of that PIF should on a and in Carter et al. for concerns could be the of habitat specialization (e.g. Reed and the of as limited of it is to of for most species. are to the to to and and should to In the for threats greater is useful to the to which threats will to in the can be difficult to and difficult to to Carter et past which to than are to The Committee believes that to and to are important to the PIF priority might the and the of The of a population the and to the factors that are a that are and that the of might be more useful than the of past or for the future. it be to the of most factors that are a species to in the (1) of have been (2) of are to (3) of have of are and of are it be to the relative with which a species can be This would a of a and and the and to the factors that have it to it will to a population of than a population of because the species has a low and on forests that require to the species many habitats including and has a relatively high The Committee that PIF of its The as not to be based on relative on of that the species has its is often defined for conservation as the number of of a species relative to the number of of species, or relative to the that the species can is the number of which to be to the that PIF has et al. are based on the number of birds for the Bird the species with the its range over the of to are is based on of in et al. the PIF of is large birds have a more because they are always uncommon relative to would be as a or they are common for a large and would to be at low relative however, a species would a of if it as as that species if its the use of a can difficult to species with North American populations, and high because their based on of in Central and South America. Thus, the that a species is of than its relative to other species or to other populations of the species. is useful as a of a risk of extinction it is most because extinction risk is to population 1993). is useful in a prioritization scheme, the of its for local conservation the might more be and should be interpreted from The PIF priority scheme on to provide an of the and for species that are covered by the A scheme is for as a for species that are in the is needed for many North American species that are by the in the United States and and for species et al. that species that are breeding to high or high or are limited to or three to enable of population in the species include some and rare and as as many endangered species. In some are by (e.g. and The Committee is that a prioritization scheme with a of and ranks for species could result in and we PIF to the of approach would be to for species, such as at to or of to with or to if species been in the The Committee believes that population are an important of a prioritization process should not be the focus of a ranking A population often is a more that a species is in than is on or A species from an or such as an changes in land or and the of have been as a to many species et al. population can be of conservation (e.g. habitat they also be a result of that plant changes represent populations to their more of (e.g. species in the other some species and vegetation that is to needed to and be among the most threatened species. factors are not in the PIF and for have however, are in the to which the of an area to populations of a in the future. to the which is to include habitat and other factors such as parasitism, pesticides, such factors often are with habitat and are most of habitat a reasonable of the threats with is considered with species is a recent The PIF scheme priority to species that are of taxa, or to diverse that are of and a might be as (1) any species not in of the (2) in the in the (3) with in the in the or the of a be included in the Arguably, of such as the represent unique and should be a higher priority than of species or species that are of diverse a would an evolutionary to the PIF prioritization the of such a could be because in are are and of species also be of in the Committee not a scheme PIF to the of to develop a that its needs. the role of some birds as be formally as a species be to ecosystem health (e.g. as of insect and others be to species within (e.g. is to such species, which must be relatively to their roles as species. The however, that of the status of most species is difficult to et al. et al. the of and ecosystem of a potentially is however, because it the of tenet of the PIF the of keeping species so that they can to play role they play in and PIF schemes could which should also become a focus of The of the PIF ranking scheme the of of or in the scheme by use of not contribute to the priority are important in that they the of with which some of the priority However, are in the and of In the PIF also used for the to and to they used and The use of can be if species have low are not as of extinction In the PIF is the highest values are an of The Committee believes that a would be in in ranks and would in needs. we that PIF should the of in ranks to a species by developing for the most important rankings must be as as if the PIF scheme is to be as it is important to and the use of The are the most and are to be the might help evaluate as would the used to each ranking on a would to the of rankings and would help to focus and are more useful for evaluating than are which that the PIF approach of ranks is the of the PIF prioritization process on through that the ranks are which has not been Thus, the Committee believes that the approach to ranking by PIF should to of ranks of the used to and the threats and for the Committee believes that the PIF process for species is the Committee has a number of that should be before results from the ranking scheme are for conservation the Committee has a number of concerns about the PIF should be used in conservation Partners in Flight of prioritization would be used for bird conservation plans in the that the Committee The et al. that of the PIF are bird conservation and land management can sort by a priority or use more than In PIF that the priority can be to a conservation priority PIF that can be it provides with value and it might be the for setting conservation priorities would on a ranking ranking schemes have been used for relative extinction risk among species (e.g. et al. 1990, et al. Reed The is to that used in the PIF scheme and (1) to be to the of extinction, (2) for a value to each of each (3) a value for each to each species, and the values each to a value for each species. The are as if they a to the of ranking schemes are because can be and the approach results with for management ranking however, have a number of and Norton of species and factors that the risk of extinction is and often are for risk a it is not which should be used and of should be developing a ranking In can because of among range and population are not and et al. 1998). more the Committee PIF rankings for the birds of that among five of the PIF considered with the other to and to and and and to and to among PIF priority for species of birds of among PIF priority for species of birds of This that there is among most PIF priority which of a among can cause The is a which can by the of become the of because the of among changes among species, so the by among species. The is as in the example of of range and population of can cause in ranking is not a if the are considered a of often about the relative different for each and the of This a value to a for a species, are if a among species from the is the goal. the value for the for different species must have the to the of if a and an American each a value of for they must have of as a result of the value for different for the or for different species must have the to the of are not the values be among or among species. an to the Committee that the for each in the PIF scheme be used to species a to conservation priority. In a scheme, species are by different a for extinction risk et al. 1986, Reed the scheme that of the Union for the Conservation of or 1991, et al. schemes provide of the and they are to the risk of schemes have been criticized as and Norton they the of are considered in a is not a because represent different a species might be of conservation to be PIF the PIF priority could be and for et al. The Committee developed a set of to provide an example of to approach with the PIF prioritization of conservation based on of PIF approach on the PIF for by the species lists and ranks with the The from highest to priority (see and are federally listed or are listed by the state or of species have been as of management before any prioritization has been they are important to any conservation they are not the of the PIF of have populations that are have a or face a high of of (3) have populations that are and experiencing or population are not and threats are of (2) have populations that are relatively common and need to be common. at (1) include native species that are not listed in to are not native to North or they as populations that from by Conservation plans should species they a special management such as of a ranking scheme that would be to North American birds the PIF prioritization are for of for species with different that any of the of a ranking scheme that would be to North American birds the PIF prioritization are for of for species with different that any of the The Committee the rankings for each species in the The ranking and of of of at and could be developed if smaller of species are of the rankings a the and the PIF The Committee believes that PIF would from a scheme and PIF to use its resources to approach in more The Committee also that PIF should the for developing a for the PIF that is to review in the that the prioritization scheme was the task of the priority ranks has been by a PIF process or is in the of and others et al. the Committee the of PIF the in and in the of local to use in a that they the could to and of the PIF PIF should seek on the prioritization or should be used for conservation of the of a ranking in lists of species at risk to it to habitats and ecoregions (e.g. et al. et al. or to threats that groups of species. is the of PIF to the it can for its and ranks to each species should be periodically three to five years to keep the The Committee has or A thoughtfully constructed scheme that ranks the relative susceptibility of birds to extinction and large-scale declines can play a useful and important role in conservation efforts if it is periodically evaluated and continually The of the PIF approach is and the need for a prioritization scheme that local and global a ranking scheme for species within the United States is the PIF ranking scheme of the United States is and species should be a of or in a because their relative risks of extinction are not conservation included in the PIF prioritization scheme are important and for ranking the susceptibility of birds in the United should be to the to and to A prioritization scheme with a of and ranks could result in and we PIF to to such The of should be to the of a A would be in in ranks and would in PIF should the of in ranks to a species by developing for the most important The PIF prioritization scheme to to of PIF should of the used to and and they should provide for PIF should develop a for the results of the prioritization and the should be to The for each in the PIF prioritization scheme should be used to species a to its conservation priority of to a and PIF should review the ranks to each species three to five years to keep the The Committee and for of Muehter in of The National Audubon Society and the American Ornithologists' Union committee in of the