Notas sobre a ecologia e a preservação de Nothochilus coccineus Radlkofer (Scrophulariaceae), espécie endêmica ao Maciço do Caparaó, ES/MG

Abstract

O presente trabalho apresenta dados básicos sobre a ecologia e a distribuição de N. coccineus Radlk., a única espécie do gênero, endêmica nos campos de altitude do Maciço do Caparaó, sudeste do Brasil, no Parque Nacional do Caparaó. A estrutura espacial da população e os elementos relevantes da paisagem foram tratados no contexto das suas influências na dinâmica de população desta espécie rara e ameaçada. Observou-se que N. coccineus encontra-se restrita a populações disjuntas acima de 2.450m, nos picos mais altos do maçico. Nesses picos cresce N. coccineus somente nas encostas íngremes das faces sul e oeste, e em sítios com solos profundos e húmicos. A presença de bambus do gênero Chusquea pode ser necessária para a ocorrência de N. coccineus, pois as raízes de Chusquea foram muitas vezes encontradas parasitadas. Baseando-se em comparações estatísticas entre características de solo, altura de plantas, e crescimento desde 1994, pode-se concluir que as encostas de face sul parecem fornecer o habitat ótimo para N. coccineus. As distâncias entre as populações e o alcance um tanto limitado da dispersão de sementes podem favorecer o isolamento genético de algumas das populações mais remotas, contudo o pastejo do gado e a alta freqüência de incêndios antropogênicos nos campos de altitude do Caparaó constituem-se claramente nas maiores ameaças à sobrevivência da espécie e do gênero a curto prazo.

A New Genus of Microteiid Lizard from the Caparaó Mountains, Southeastern Brazil, with a Discussion of Relationships among Gymnophthalminae (Squamata)

“…There are no climatic stations in the highest mountains, but according to IBAMA (Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renová veis), the Brazilian environmental agency, the maximum and minimum annual temperatures vary respectively from 34u to 36u C and 24u to 0u C. Estimated annual mean temperatures calculated after regional elevational temperature gradients (ca. 0.55u C/ 100 m) and verified by soil temperatures measured at less than 70 cm indicates that annual mean temperatures fluctuate around 10.5u C at 2400 m, and 8.5u C at 2800 m (Safford, 1999b). We left a data logger at 2400 m altitude, at a relatively protected site near Pico da Bandeira, between December 2004 and November 2005.…”

“…6), Brazil. This highly elevated and deeply dissected mountainous area is formed by middle to late Tertiary uplifted blocks of igneous or highgrade metamorphic rocks and includes the three highest mountains of eastern tropical South America: Pico da Bandeira (2890 m), Pico do Calçado (2840 m), and Pico do Cristal (2780 m), respectively the third, fourth, and sixth highest mountains in Brazil (Safford, 1999a(Safford, , 1999b. The high elevation, plus their exposure to southern polar fronts, makes these mountains the coldest spots in eastern South America.…”

Brazilian Páramos II. Macro‐ and mesoclimate of the campos de altitude and affinities with high mountain climates of the tropical Andes and Costa Rica

“…The campos de altitude are found exclusively on igneous and metamorphic substrates, mostly of Precambrian age (Machado‐Filho et al ., 1983); soils are highly acidic and nutrient‐poor, ranging from moderately lateritic clays to deep, organic mulls and, more rarely, mors (Modenesi, 1988; Martinelli & Banderia, 1989; Safford, 1999b, 1999c). Vegetation in the campos de altitude is physiognomically dominated by graminoids, especially tall‐stemmed bunchgrasses and bamboos, and sclerophyllous shrubs (Fig.…”

Brazilian Páramos I. An introduction to the physical environment and vegetation of the campos de altitude

“…At a scale of 1:1,000,000, the Projeto Radambrasil (Oliveira et al ., 1983) mapped and classified mountain soils in the southeast as (1) mountainous to very steep, medium to argillic textured, allic Humic Cambisols; (2) rocky, mountainous to very steep, medium textured Humic Lithosols; and (3) Rocky Outcrops. On a more local scale, soils range from moderately lateritic clays on well‐drained slopes of colluvium, to deep and highly organic profiles in poorly‐drained bogs; peaty soils may approach 3 m in depth, with A‐horizon organic C content generally ranging between 10% and 30% (Modenesi, 1988; Modenesi‐Gauttieri & Toledo, 1996; Safford, 1999b, 1999c). Chemical analyses yield pH values between 3.2 (Serra dos Órgãos) and 5.7 (Serra do Caparaó), and C/N ratios range from c. 5 in C horizons, to as high as 17 to 20 in A horizons.…”

“…Depending largely on ease of access, impacts vary from negligible in the Serra dos Órgãos to catastrophic in parts of the Serra da Bocaina, where decades of heavy grazing and otherwise abusive landuse practices have left a devastated and biologically depauperate landscape. Although the impacts of grazing in the campo de altitude have not been directly studied, it seems certain that the long‐term presence of cattle and horses in these systems has had – and continues to have – negative impacts on topsoil, microclimate, water quality and runoff, and the welfare of at least some of the small, endemic plant populations that make these mountaintop habitats their home (Safford, 1999b).…”