Conservation
Although what knowledge of the ecology of austral migrants points to most having low habitat specificity (Stotz et al. 1996), the rapidly progressing environmental alteration of various habitats on the continent by humans (e.g., dry forests, Gentry 1977, 1993, Janzen 1988) may pose immediate and significant threats to at least some South American migrants which depend on specific resources throughout the year. An example of such a group is the Sporophila seedeaters, which face the threat of habitat alteration (Stotz et a. 1996) and, in some cases, capture for the pet trade and many of whose ranges are, still surprisingly imperfectly known”, (Ridgely and Tudor 1989).
In light of human-induced habitat alterations occurring on the South American continent, basic knowledge of migrant ecology such as resource use and migratory timing, as well as breeding/winter ranges and population trends will be imperative to the success of long-term conservation efforts. Such information has been collected for decades in North America and has proven useful for understanding migratory bird requirements and threats. Standardized equivalents beyond the local scale do not exist in South America, where it is not only unclear whether most populations of migratory species are declining, it is impossible with current data to even explore such a possibility.
Table 1 (below) presents the austral migrant species of most immediate concern, built from the list of austral migrant species in Database E of Parker et al. (1996), species which they included in the list as austral migrants that occupy new zoogeographic regions, habitats, or elevational ranges in winter. Partial migrants (which make up almost 70% of austral migrants; Stotz et al. 1996) were not considered in Table 1, since the migration of these species is a population-level process and it is therefore not evident whether it is the resident or migrant populations of these species which are threatened. Such a situation highlights the need for immediate population-level natural history and hypothesis-based research and censusing, in order to make adequate conservation recommendations at finer taxonomic and geographic scales.
Of 78 austral migrants listed in Database E by Parker et al. (1996), only 4 fit the criteria used to build the table, reflecting the general condition among austral migrants of low risk of immediate extinction (Stotz et al. 1996). None fit the CP1 (urgent conservation priority”) category of threat of Parker et al. (1996). Furthermore, of 327 species listed as Threatened” by Collar et al. (1992), only 2 fit the criteria. However, because of the lack of information on the biology and population status of most austral migrants, this list will likely grow with more research.
Table
1. Complete austral migrant species of most immediate
concern.
Species
in Database E of Parker et al. (1996) were used. Two measures
of conservation concern are used: Conservation Priority” levels
taken from Parker et al. (1996). Although 4 Conservation
Priority (CP) levels used in Parker et al. (1996), only the first
two (CP1 = urgent and CP2 = high, were used). Threatened” category
taken from Collar et al. (1992). A indicates that the species
was not listed for that category.
| Species | Conservation Priority* | Threatened** |
|---|---|---|
| Chloephaga rubidiceps | CP2 | - |
| Anas specularis | CP2 | - |
| Sporophila palustris | CP3 | yes |
| Sporophila zelichi | CP2 | yes |
| * CP2 = high conservation
priority (on a 4 point scale from 1 = urgent, 2 = high,
3 = medium, and 4 = low)(from Parker et al. 1996). ** from Collar et al. (1992) |
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Literature Cited
A list of literature cited in this website on austral migration. Additionally, there are included citations on Neotropical biology and ecology in general.