Floristics and life-forms along a topographic gradient, central-western Ceará, Brazil

Abstract

To test whether the flora is organized in discrete or continuous units along a topographic gradient, three physiognomies were assessed on different soil classes in a semi-arid region of northeastern Brazil: caatinga (xeric shrubland) at altitudes from 300 to 500 m, deciduous forest at altitudes from 500 to 700 m and carrasco (deciduous shrubland) at 700 m. In each physiognomy a species inventory was carried out, and plants were classified according to life- and growth-forms. Species richness was higher in the deciduous forest (250) than in the carrasco (136) and caatinga (137). The caatinga shared only a few species with the carrasco (6 species) and the deciduous forest (18 species). The highest species overlap was between the deciduous forest and the carrasco (62 species). One hundred and four species occurred only in the caatinga, 161 only in the deciduous forest and 59 only in the carrasco. Woody species predominated in physiognomies on sedimentary soils with latosol and arenosol: 124 species occurred in the deciduous forest and 68 in the carrasco. In the caatinga on crystalline basement relief with predominance of planosol, herbs showed the highest species richness (69). Comparing the biological spectrum of Brazilian plant life-forms, the caatinga stood out with higher proportion of therophytes and chamaephytes. Considering the flora of the three phytophysiognomies studied here, we can affirm that the caatinga is a discrete floristic unit.

Hydraulic architecture of lianas in a semiarid climate: efficiency or safety?

“…Both vegetation types grow in a semiarid climate and have different richness and abundance of lianas (Araújo & Martins 1999;Araújo et al 2011). The study areas are located within the Serra das Almas Private Natural Heritage Reserve (5°7'001"S and 40°52'220.79"W), which is in the mid-western region of the state of Ceará and is located in the northeastern semiarid region of Brazil.…”

Variações locais na riqueza florística em duas ecorregiões de caatinga

“…Análises de padrões de diversidade, distribuição e endemismos das Leguminosae em áreas de caatingas com fisionomias aparentemente homogêneas têm demonstrado que, sob a denominação de caatinga, provavelmente existam duas biotas historicamente distintas (Queiroz 2006;Cardoso & Queiroz 2007). Estes autores argumentam que as ecorregiões da Caatinga poderiam ser subdivididas em uma biota associada às superfícies sedimentares arenosas, enquanto a outra associada aos solos geralmente pedregosos derivados de rochas cristalinas pré-cambrianas (Queiroz 2006;Cardoso & Queiroz 2007;Araújo et al 2011). De fato, além de apresentar maior densidade de indivíduos por espécie (AndradeLima 1981;Lyra 1982;Rodal 1992;Rocha et al 2004), a caatinga associada às bacias sedimentares é também mais rica em espécies e endemismos do que a caatinga sobre solos derivados do embasamento cristalino (Queiroz 2006).…”

New records of mites (Acari: Spinturnicidae) associated with bats (Mammalia, Chiroptera) in two Brazilian biomes: Pantanal and Caatinga

“…The RPPN Serra das Almas (05° 15' S/41° 00' W) comprises 6,146 hectares and is considered an Outpost of the Caatinga Biosphere Reserve situated in the municipality of Cratéus, state of Ceará (ARAÚJO et al, 2011). The RPPN Sesc Pantanal (16° 41' S/56° 24' W) represents the largest RPPN in Brazil, with approximately 106,000 hectares between the rivers Cuiabá and São Lourenço in the municipality of Barão de Melgaço, state of Mato Grosso.…”