Ronald Zanetti

A social and ecological assessment of tropical land uses at multiple scales: the Sustainable Amazon Network

Science has a critical role to play in guiding more sustainable development trajectories. Here, we present the Sustainable Amazon Network (Rede Amazônia Sustentável, RAS): a multidisciplinary research initiative involving more than 30 partner organizations working to assess both social and ecological dimensions of land-use sustainability in eastern Brazilian Amazonia. The research approach adopted by RAS offers three advantages for addressing land-use sustainability problems: (i) the collection of synchronized and co-located ecological and socioeconomic data across broad gradients of past and present human use; (ii) a nested sampling design to aid comparison of ecological and socioeconomic conditions associated with different land uses across local, landscape and regional scales; and (iii) a strong engagement with a wide variety of actors and non-research institutions. Here, we elaborate on these key features, and identify the ways in which RAS can help in highlighting those problems in most urgent need of attention, and in guiding improvements in land-use sustainability in Amazonia and elsewhere in the tropics. We also discuss some of the practical lessons, limitations and realities faced during the development of the RAS initiative so far.

Diversidade de formigas (Hymenoptera: Formicidae) da serapilheira em eucaliptais (Myrtaceae) e área de cerrado de Minas Gerais

The inventory of the ant fauna in a cerrado area and in eucalypt plantations with five classes of understory ages, has been carried out in Bom Despacho (MG), in the aim to evaluate the effect of plantation age on the diversity of native cerrado ants. Fifteen areas of eucalypt have been sampled, being three per age class, as follows: areas with understory of 0 to 2, 2 to 4, 4 to 6, 6 to 8 and 8 to 10 years old, respectively). The same has been made in a native vegetation area used as control . The ants from the litter have been extracted using Winkler sacks. One hundred and forty three ant species have been collected, belonging to six subfamilies, being 67 in the native area (50 samples) and 133 in the eucalypt plantations (750 samples, corresponding to an average of 52 species per group of 50 samples, or sampled area). With the Chao 2 diversity estimator index, there is no significant differences between areas (Kruskal-Wallis, P>0.05). It has been demonstrated that most of the species found in native vegetation occur also in the eucalypt plantations, although these ones present a drastic diminution of the species density, suggesting that the ant regional richness do not depend on the complexity of the habitat, because the cerrado ant fauna is well conserved in the eucalypt plantations, contradicting most of the literature on this subject.

Combate sistemático de formigas-cortadeiras com iscas granuladas, em eucaliptais com cultivo mínimo

The efficiency of a systematic application of baits against leaf-cutting ants was evaluated in a eucalypus plantation under a minimum cultivation system, in areas owned by Celulose Nipo-Brasileira S.A. (CENIBRA), in Belo Oriente, Minas Gerais, Brazil, from September to December 1996. Treatments consisted of applying a granulated bait with sulfluramide (0.3%) in a systematic manner in bulk and plastic bags at a dose of five grams every 6 m2 (T1) and 10 grams at each 12 m2 (T2). Mortality of colonies of leaf-cutting ants was evaluated 30 days after bait application. A. maximum of 396.3; 285.2; 59.3; 55.6; 29.6 and 14.8 colonies of Mycocepurus goeldii, Sericomyrmex sp., Acromyrmex subterraneus molestans, Atta spp., Acromyrmex balzani and Acromyrmex niger (Hymenoptera: Formicidae), respectively, was found per hectare. The efficiency of this granulated bait, applied in a systematic manner, varied with the method and species of leaf-cutting ants. Higher efficiency was obtained for A. subterraneus molestans, with 69.2% of dead colonies with the bait applied in bulk and 62.5% when it was applied in plastic bags. This shows that bait distribution in the eucalyptus plantation was performed at a larger spacing than the foraging area of leaf-cutting ants and/or that the dose was insufficient.

Conservation value of alternative land-use systems for dung beetles in Amazon: valuing traditional farming practices

Land-use systems (LUS), placed in originally forested areas, represent different degrees of opportunity for species conservation. In this study, we examined the dung beetle communities in order to identify the conservation value of different LUS: primary forest, old secondary forest, young secondary forest, agroforestry, agriculture and pasture in Western Amazon. The LUS were sampled in two campaigns during the highest precipitation period and dryest period. The primary forest has a high number of total and exclusive species. Large beetles show a continuous decreasing in richness and abundance from primary forest to pastures, while small ones are not sensible to intermediate systems (secondary forest to agriculture) in terms of species richness and exhibit a increase in abundance at agroforest and agriculture when contrasted to secondary forest and pasture The beetle community composition was not sensible to secondary forest recovering time. Secondary forests and agroforestry stood out as harboring many species shared with primary forests. Cloud-point dispersion (average dissimilarity) increased from primary forest towards LUS’s submitted to more intense use. The higher sampling points similarity observed in primary forest might be the result of the relative stability of this system, given that environmental impacts might increase variability in community structure and beta diversity. Increase in beta diversity as expressed by greater dispersion of sites in multivariate space suggests that these areas are dependent on nearby species pools, possibly primary forests, and harbor a higher spatial heterogeneity in species composition. This high variability can overestimate the importance of occasional species, thus biasing the actual value of alternative LUS for biodiversity conservation.

Impacto de iscas formicidas granuladas sobre a mirmecofauna não-alvo em eucaliptais segundo duas formas de aplicacação

The effect of localized and systematic use of granulated bait for cutting ant control was assessed on a community of non-target ants in eucalyptus in the municipality of Bom Despacho, Minas Gerais State, Brazil. The ants were collected in Winkler traps on three occasions: eight days before bait distribution, eight and sixty days after distribution by removing the mirmecofauna from 50 1-m2 samples of litter. A total of 102 species was collected belonging to six sub-families. The seven most frequent ant species were analyzed in more detail to assess more precisely the consequences of insecticide treatments. The study showed that systematic control caused negative and more prolonged impact on the ant community than localized control.

Efeito da densidade e do tamanho de sauveiros sobre a produção de madeira em eucaliptais

The number and size of leaf-cutting ant nests in eucalypt plantations were related to the wood production. Data from the eucalypt forest inventory from Mannesmann Florestal Ltd., in Joao Pinheiro, MG, Brazil, were analyzed from 1991 to 1996. These data were correlated with those from a leaf-cutting ant monitoring program (SIMFOR) and also with those of the understory vegetation cover. The number of leaf-cutting ant nests found in the studied area was sufficient to reduce wood production. The wood production of Eucalyptus camaldulensis Dehnh, E. citriodora Hook and E. tereticornis Smith was more affected by leaf-cutting ant damage than E. cloeziana F. Muell. and E. urophylla S.T. Blake.

EFICIÊNCIA DE ISCAS GRANULADAS À BASE DE SULFLURAMIDA E DE CLORPIRIFÓS NO CONTROLE DE Atta sexdens sexdens(HYMENOPTERA: FORMICIDAE), NO TRÓPICO ÚMIDO.

This research was developed in hibrid urograndis (Eucalyptus urophylla χ Eucalyptus grandis)plantation belonging to Jari Celulose S.A., in Para State, Brazil, from August 1994 to January 1995. The objective was to test one granulated bait with sulfluramid and three others with chlorpirifos in three dosages compared to 10 grams of dodecachlor (0.45%) bait per square meter of ant nest against Atta sexdens sexdens(Hymenoptera: Formicidae). The bait with sulfluramid showed 77.78%; 100.00%; and 88.90% efficiency against A. sexdens sexdensat 6, 8, and 10 grams while the dodecachlor bait showed 100.00% control. The other baits and dosages showed efficiency below 45.00%.

Riqueza de formigas (Hymenoptera, Formicidae) da serapilheira em fragmentos de floresta semidecídua da Mata Atlântica na região do Alto do Rio Grande, MG, Brasil

The community of Formicidae (Insecta, Hymenoptera) in semideciduous seasonal forest of the Atlantic rain forest biome was studied in remnants ranging from 2.99 to 45.45 ha, in the region of the Alto do Rio Grande, Minas Gerais State, Brazil. The ants collected in 15 samples of litter of one square meter each, using Winkler extractors method, in each forest fragment. Each sample were taken at intervals of 50 meters. A total of 142 species of ants, were distributed into 40 genera, 23 tribes and 10 subfamilies. The communities showed a high richness and diversity indices values. The size of the fragments did not influence the ant richness.

Avaliação rápida da diversidade de formigas em sistemas de uso do solo no sul da Bahia

We aimed to compare the soil ant diversity in different land use systems from Atlantic Forest area, in Southern Bahia state, Brazil. The ants were sampled in 16 sites: two primary forest sites (un-logged forest); three young secondary forests (<8 years old); three intermediate secondary forests (8-20 years old); three old secondary forests (>20 years old); three Eucalyptus grandis plantations (3-7 years old), and two introduced pastures. Each site was sampled in three sampling points 15 m apart, and distant over 50 m from the site edge. In each sampling point we gathered the litter from a 1 m² and extracted the ants with Winkler extractors during 48h. We found 103 ant species from 29 genera and eight subfamilies. The five richest genera were Pheidole (19 species), Solenopsis (8), Apterostigma (10), Hypoponera (7) e Paratrechina (5). The highest ant richness density was found in the primary forest (7.4 species/sample; S = 37; n = 5); followed by the old secondary forest (5.33 species/sample; S = 48; n = 9); young secondary forest (5.25 species/sample; S = 42, n = 8); eucalyptus plantation (4.22 species/sample; S = 38, n = 9), intermediate secondary forest (3.5 species/sample; S = 35, n = 10, and introduced pasture (2.67 species/sample; S = 16, n = 6). The ecosystems with higher structural complexity showed the highest ant richness density by sample. Therefore, in the Atlantic Forest region, the eucalyptus plantation is a better alternative of land use to conserve the ant biodiversity than pastures, and quite similar to native secondary forests in ant community characteristics.

Influence of the cultivated species and of the native vegetation on leaf-cutting ant nests density in eucalyptus plantations

The effects of eucalyptus species and ages, as well as the native vegetation around the eucalyptus plantation, on leaf-cutting ant nests density was studied in a reforested area of V & M Florestal Co., in Joao Pinheiro, MG, Brazil. Data were obtained from the leaf-cutting ant monitoring program (Simfor) of the company, from the entire planting fields, with different ages, from 1991 to 1996. As a result, the number of leaf-cutting ant nests increased from the beginning up to three years of age of the forest, but maintained the same number afterwards. Native vegetation strips reduced the number of nests in the reforested areas, while native forest fragments showed an opposite effect.The effects of eucalyptus species and ages, as well as the native vegetation around the eucalyptus plantation, on leaf-cutting ant nests density was studied in a reforested area of V & M Florestal Co., in Joao Pinheiro, MG, Brazil. Data were obtained from the leaf-cutting ant monitoring program (Simfor) of the company, from the entire planting fields, with different ages, from 1991 to 1996. As a result, the number of leaf-cutting ant nests increased from the beginning up to three years of age of the forest, but maintained the same number afterwards. Native vegetation strips reduced the number of nests in the reforested areas, while native forest fragments showed an opposite effect.