Macrosamanea macrocalyx

Esilva, Wanderson Luisda Silva, Batistasoares, Marcosvinicius, Morim, Marli Pires, Iganci, João Ricardo Vieira & Santos, João Ubiratan Moreira Dos, 2015, Rediscovery of Macrosamanea macrocalyx (Leguminosae: Mimosoideae), a threatened endemic species from the Middle Xingu River, Amazonia, Brazil, Phytotaxa 224 (3), pp. 276-282 : 280-281

Conservation of Macrosamanea macrocalyx

Macrosamanea macrocalyx is strongly threatened, since the only known population occurs in the area directly affected by the construction of the Belo Monte hydroelectric dam. Even though the area where the species occurs is seasonally flooded, the construction of the dam will permanently flood the area ( Eletrobrás 2009), and the local vegetation is already being suppressed ( Fig. 1a ). The species has probably already lost some of its natural habitat due to urbanization. Furthermore, this region has been intensely deforested during the past 30 years. The remaining fragmented forest areas include different vegetation formations including the terra firme forest, inundated forest, and seasonal vegetation associated with rocky outcrops ( Eletrobrás 2009).

Macrosamanea macrocalyx occurs in this very restricted area, with a population composed of few individuals. Even though information from fieldwork and herbarium collections suggests that the species is narrowly restricted in its distribution, considering the lack of collections in Amazonia ( Forzza et al. 2012), its distribution could still be underestimated.

Macrosamanea macrocalyx was not mentioned in the list of plant species for the environmental impact study for the dam construction ( Eletrobrás 2009). Consequently, the species was also not included in the local flora rescue operation.

Considering this background, and based on the IUCN criteria ( IUCN 2001) and threats listed in CMP/IUCN version 2.1, we suggest that M. macrocalyx should be included in the Critically Endangered (CR) category in both the IUCN and Brazilian Red Lists, since after 90 years it is found only in the same area where the type was originally collected. The species occupies an area of <10 km ², and it is threatened by the reduction or suppression of both the occurrence extension and the occupation area, as well as the habitat quality and the small number of mature individuals. The population is estimated as comprising fewer than 50 mature individuals. Following the IUCN criteria, the species should be categorized as CR B2b (i, ii, iii, iv and v) and D.

In an attempt to maintain the species ex situ, seeds were collected and are being cultivated in the Laboratory of Fruit and Seed Morphology, in the Museu Paraense Emílio Goeldi ( Fig. 1j ). Some individuals will be planted in the Zoobotanical Park of the Museu Emílio Goeldi, as a source for possible future reintroduction in the wild. Meanwhile it is essential to improve public policies for conservation of wild flora in the areas affected by the new dam.

Figures

FIGURE 1. Macrosamanea macrocalyx (Ducke) Barneby & J.W.Grimes. A. Ambé creek,Altamira, PA. B. Habit. C. Leaflets. D. Flowers showing styles. E. Inflated calyx. F. Flower G. Immature fruit with persistent calyx. H. Mature fruit with persistent calyx. I. Seeds. J. Seedling. K. Cotyledons. L. Seed showing papery-membranous testa. A–L photos by W.L.S. Silva.