Flora and life-form spectrum in an area of deciduous thorn woodland (caatinga) in northeastern, Brazil

Caatinga, a deciduous thorny woodland vegetation, is encountered in the semi-arid region of northeastern Brazil. In view of the importance of the herbaceous component of caatinga plant communities, a characterization of the flora of the Nao Me Deixes Reserve in Ceara State, Brazil (4 degrees 49'34"S 38 degrees 59'09"W, at 210m a.s.l.) was undertaken. The reserve has 300ha of caatinga vegetation, including dense tree steppe and open tree steppe. The mean annual rainfall is 732.8 mm, concentrated between February and May (78%). The flora was surveyed at monthly intervals between February 2000 and June 2001. We encountered 133 species belonging to 47 families. The herbaceous/woody ratio was 1.4. Based on field observations, the life-form spectrum was characterized according Raunkiaer's system, and compared with his normal spectrum. The life-form spectrum observed was: therophytes (42.9%), phancrophytes (26.3%), camaephytes (15.8%), hemicryptophytes (12.8%), and cryptophytes (2.3%). Previous data on the caatinga, herbaceous flora, as well as the present study, indicate that the floristic richness of this biome has been underestimated, and that the herbaceous/woody proportion varies according to its physiognomy and water status. (c) 2006 Elsevier Ltd. All rights reserved.68223724

Flower visits, nesting and nest defence behaviour of stingless bees (Apidae: Meliponini): suitability of the bee species for meliponiculture in the Argentinean Chaco region

International audienceFour bionomical features are here described for the seven stingless bees that inhabit a new meliponine beekeeping area: the Argentinean Chaco region. The most commonly visited plants were of herbaceous habits, predominantly had flowers of white/creamy to yellowish colour, with small-sized flowers and were of moderate mass-flowering degree. Lestrimelitta chacoana was the only robber species. The most commonly found nesting substrate was large living tree trunks, and most nests were found at the base of the trunks. Sometimes, nesting substrates and floral resources were provided by the same woody plant. Cryptic small- to medium-sized cerumen tube-like unornamented nest entrances were the most commonly found. Nest defence included aggressive (Scaptotrigona jujuyensis) and docile behaviour; the latter was classified into timid and non-timid. A key to identify the Meliponini fauna of this region is provided. The regional pattern of bionomical features seems to be associated with subtropical climate conditions. The majority of these bee species are suitable for Meliponiculture in the Chaco region