Protected areas and global conservation of migratory birds

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Science  04 Dec 2015:
Vol. 350, Issue 6265, pp. 1255-1258
DOI: 10.1126/science.aac9180

Not enough protection for migrating birds

Animals that migrate pass through a varying number of regions. Each of these regions contributes to a different component of their life cycles. Runge et al. looked at the degree of protection migratory birds receive, globally, across their breeding and wintering ranges. A remarkably low percentage of migratory birds receive adequate protection across their entire ranges. Given that over half the world's migratory bird populations are declining, these results emphasize the urgency with which we must act to protect birds across their entire migratory cycle.

Science, this issue p. 1255


Migratory species depend on a suite of interconnected sites. Threats to unprotected links in these chains of sites are driving rapid population declines of migrants around the world, yet the extent to which different parts of the annual cycle are protected remains unknown. We show that just 9% of 1451 migratory birds are adequately covered by protected areas across all stages of their annual cycle, in comparison with 45% of nonmigratory birds. This discrepancy is driven by protected area placement that does not cover the full annual cycle of migratory species, indicating that global efforts toward coordinated conservation planning for migrants are yet to bear fruit. Better-targeted investment and enhanced coordination among countries are needed to conserve migratory species throughout their migratory cycle.

From the writings of Aristotle (1) to the musings of Gilbert White in Georgian England (2), migratory birds have fascinated and inspired people for generations. Migrants undertake remarkable journeys, from endurance flights exceeding 10,000 km by bar-tailed godwits (Limosa lapponica) (3) to the annual relay of arctic terns (Sterna paradisaea), which fly the equivalent of the distance to the moon and back three times during their lives (4). Migratory species make major contributions to resource fluxes, biomass transfer, nutrient transport, predator-prey interactions, and food-web structure within and among ecosystems (5) and play an important role in human culture (6). Yet more than half of migratory birds across all major flyways have declined over the past 30 years (7).

Threats in any one part of a annual cycle can affect the entire population of a migratory species (8), and so environmental management actions for migrants need to be coordinated across habitat types, seasons, and jurisdictions (8). Protected area designation is a widely used approach for averting species loss (9) because it can reduce habitat loss, habitat degradation, hunting pressure, and disturbance (10). Yet the extent to which the distributions of migratory species are covered by protected areas globally is poorly understood. Many previous global and regional species conservation assessments and prioritization analyses either omit parts of the annual cycle or treat all species’ distributions as static (912). Here, we explore how protected area coverage of migratory birds varies across their annual cycle and among countries and compare their current levels of protected area coverage against standard conservation targets. Overlaying maps of protected areas (13) onto distribution maps of the world’s birds, we assessed whether the proportion of each species’ distribution covered by protected areas met a target threshold (9, 11). For migratory species, we set targets for each stage of the annual cycle separately for the 1451 migratory birds, with mapped distributions throughout their annual cycle.

We discovered that 91% of migratory bird species have inadequate protected area coverage for at least one part of their annual cycle, despite individual elements of the annual cycle being well protected for some species (Table 1). This is in stark contrast to 55% of nonmigratory species with inadequate protected area coverage across their global distribution. A typical migrant relies on two or three disjoint geographic locations, and the chance that they are all adequately conserved is probabilistically lower than for a single location (supplementary materials). We found that migratory species are less likely to meet protection targets as the number of seasonal areas increases and that the proportion of migratory species meeting targets is consistent with randomly allocated conservation effort (Fig. 1), indicating that despite widespread recognition of the need for an internationally coordinated approach to conservation of migratory species, protection is not yet systematically coordinated across the seasonal ranges of species. Twenty-eight migratory bird species have no coverage in at least one part of their annual cycle, and 18 of these have no protected area coverage of their breeding range. Two species lack any protected area coverage across their entire distribution (Table 1). Disturbingly, less than 3% of threatened migratory bird species have adequate protected area coverage across all parts of their annual cycle (table S1).

Table 1 Protected area coverage of migratory and nonmigratory bird species.

Representation targets are based on species’ geographic range size, with a target of 100% of a distribution to be covered by protected areas where the geographic range is <1000 km, log-linearly decreasing to 10% where the range size is >250,000 km (10, 12).

View this table:
Fig. 1 The shortfall in protected area coverage for migratory species is related to their requirement for protection across each of their seasonal ranges—resident, breeding, nonbreeding, and passage ranges.

(A and B) The proportion of migratory species meeting targets for (A) protected area coverage of their distribution and (B) complete coverage of all key sites (IBAs) identified for them decreases rapidly with the number of seasonal ranges, which is consistent with a random allocation of conservation effort. Dashed lines represent the proportion of species expected to meet targets where conservation is systematically coordinated across the seasonal ranges of species (so that an appropriate proportion of each part of the range is covered by protected areas).

Widespread migrants may benefit more from broader-scale policy responses (such as targeting forestry and agriculture planning and practices) than individual site-based interventions (14). However, for nearly all bird species worldwide for which site-based conservation is appropriate and needed, key sites—Important Bird and Biodiversity Areas (IBAs)—have been identified, so it is informative to assess protection levels for such sites (15). A total of 8283 IBAs has been identified for 885 migratory bird species, either because they congregate in sufficient numbers so that any individual site holds >1% of the global or flyway population of one or more migrant species (43% of sites) or because they support populations of one or more globally or regionally threatened migrant species (55% of sites; the remainder relate to other IBA criteria). The protected area coverage of IBAs for migrants provides a finer resolution metric of the degree to which protected areas adequately cover the key locations for the world’s migrants and accounts for some of the variation in abundance of migratory species across their distribution; for example, some migratory species are widely dispersed when breeding but congregate in large numbers in a few particularly important sites when on migration or in their nonbreeding range. We discovered that for only 2.9% of migratory birds are their IBAs fully protected across each of their seasonal areas (table S2). On average, 22% of the IBAs identified for each migratory species are completely covered by protected areas, and an additional 41% are partially covered, which is consistent with nonmigrants (24 and 42%, respectively) (table S2). Most IBAs for migratory species are identified in their breeding distributions (77% of migratory species with an IBA), yet for the majority of those species, the breeding range is the least well-protected stage of the migratory cycle. IBAs along the migratory route from breeding to nonbreeding areas are most likely to be incompletely protected, with only 16% being completely covered.

Our results highlight an urgent need to coordinate the designation of protected areas across the annual cycle (Fig. 2). For example, habitat loss is one of the key threats to the Vulnerable red-spectacled amazon (Amazona pretrei), a migratory parrot of Brazil (16), yet less than 4% of its distribution occurs within protected areas, with negligible coverage of seasonal breeding and nonbreeding areas (17). Similarly, the great knot (Calidris tenuirostris), a once abundant migratory shorebird, is now classified as globally Vulnerable (18). Just 7% of its distribution is covered by protected areas during migration, where the species congregates in high numbers. Filling the protection gaps for such species throughout their annual cycle is necessary for their conservation.

Fig. 2 Global inequity in protected area coverage of migratory birds.

(A to C) The percentage of migratory bird species within each country meeting targets for protected area coverage (A) for each part of their migratory range within that country, (B) for each part of their migratory range globally, and (C) the percentage area covered by protected areas in that country. Targets are scaled by the size of each part of the seasonal distribution. There is a difference in the range of the color ramp between the three maps.

Because migrants move across international borders, achieving their protection is a shared responsibility. Some countries (such as France and Venezuela) meet targets for protected area coverage for more than 80% of their migratory bird species, whereas others (such as China and India) meet targets for less than 10% (Fig. 2A and database S1). Countries across North Africa and Central Asia stand out as having low protected area coverage of migratory bird distributions. We also discovered wide variation in the proportion of migratory bird species occurring in each country that meet their protection targets overseas—a consequence of the migratory connections linking jurisdictions and continents (Fig. 2B). For instance, Germany meets targets for protected area coverage for more than 98% of migratory bird species occurring within its borders, but less than 13% of Germany’s migrants are adequately protected across their global range (Fig. 2). This is not simply a case of wealthy nations losing natural heritage to poor nations. Many Central American countries (with low gross domestic product) meet targets for more than 75% of their migratory species, but these species have lower levels of protected area coverage in Canada and the United States (Fig. 2).

Our analyses focus on coverage of species’ distributions and key sites by protected areas and do not account for variation in management effectiveness of protected areas or consider broader-scale conservation actions beyond protected sites. Many protected areas are inadequately managed (10), and our results based on coverage thus overestimate true protection. Indeed, achieving effective management of existing protected areas may be just as beneficial as designating new sites. However, even when well managed so as to abate core threats to migratory species such as habitat loss and hunting, protected areas are just one tool for minimizing species loss (10), and broader-scale interventions will also be needed to address all threats to migratory species. Many migratory species are widespread and undertake broad-front movements, meaning that entire landscapes need to be managed to conserve them. For instance, intensification and mechanization of grassland management is a key threat to the migratory corncrake (Crex crex), which breeds in agricultural meadows across Europe, and effective conservation outcomes for the species will involve both identifying key sites for strict protection during its annual cycle and developing incentives for farmers to implement agricultural practices that benefit the species in important areas outside reserves (16). Full knowledge of the spatial disribution of threats, how they can best be abated, and how they affect population dynamics across the annual cycle of each migratory species will allow conservation actions to be prioritized most efficiently (18). Alongside identifying key sites for protection, broader policy instruments need to be strengthened or developed in order to conserve migratory species.

Protected areas are usually designated at the national scale, but collaborative international partnerships and concerted intergovernmental coordination and action are crucial to safeguard migratory species (7). A number of international agreements [such as the Convention on the Conservation of Migratory Species of Wild Animals (CMS) and the Ramsar Convention on Wetlands] recognize the specific challenges associated with migratory species and attempt to deliver special protection to migrants. Migratory landbirds in particular lack coverage under flyway-based bird conservation instruments (19), although this is now being addressed through initiatives such as the African-Eurasian Migratory Landbird Action Plan being developed under the CMS (20). However, only 120 nations are parties to the CMS, and there is an urgent need to strengthen other agreements, including those between range states in specific migratory flyways. Internationally coordinated action (particularly within flyways) through these and other mechanisms will require substantially greater international leadership and resourcing.

Although there has been considerable focus through the Convention on Biological Diversity (CBD) Strategic Plan on increasing both the size and representation of the global protected area estate (21), with some success (12), our results highlight a failure to consider adequately the linkages between protected areas. Our data show that migratory species remain very poorly represented in the global protected area system. The CBD’s Aichi Targets for 2020 (21) will likely drive the greatest expansion of protected areas in history and represent a key opportunity for conserving migrants (15). However, safeguarding the world’s migratory birds will require better resourcing and use of existing international mechanisms to target new and expanded protected areas, enhance enforcement and management effectiveness, and greatly strengthen coordination between countries.

Supplementary Materials

Materials and Methods

Supplementary Text

Figure S1

Tables S1 to S5

References (2228)

Databases S1 to S3

References and Notes

  1. Acknowledgments: This work was supported by the Australian Government’s National Environmental Research Program, Australian Postgraduate Awards to C.A.R. and J.O.H., and an Australian Research Council Centre of Excellence for Environmental Decisions scholarship to C.A.R. The work was further supported by Australian Research Council Linkage Grant LP150101059 to R.A.F and Discovery Grant DP140100733 to J.E.M.W. We thank V. Jones for comment and discussion and all contributors to BirdLife’s International Union for Conservation of Nature Red List assessments. Data describing protected area coverage are available in the supplementary materials databases S1 to S3. C.A.R., R.A.F., and H.P.P. designed the study. C.A.R. analyzed data, created figures, and wrote the manuscript. J.O.H. prepared and analyzed data. All authors discussed the results and edited the manuscript.
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