Caça de animais silvestres na rodovia Transamazônica.

Apesar de a caça ser proibida, é praticada freqüentemente pelas populações rurais de baixa renda na Amazônia. Como base para planejamentos futuros de manejo de caça, conduziu-se um estudo de quatro meses visando analisar a caça de animais silvestres em Uruará, Pará, Brasil, uma pequena cidade na frente pioneira da rodovia Transamazônica. A atividade de caça foi estudada de abril a setembro de 2000, através de entrevistas semanais e acompanhamentos da caça (76 saídas de caça e entrevistas de 20 caçadores). Existem dois tipos principais de caça: o primeiro ocorre o ano todo, durante o dia, usando cachorros. O segundo, popularmente conhecido como "a espera", é praticado a noite, durante os meses menos chuvosos. Os caçadores caçam uma média de 3,6 vezes por mês durante os meses menos chuvosos e 0,5 vez por mês durante os meses chuvosos. As espécies mais caçadas são os caititus e queixadas (Tayassu tajacu e I pecari, 41 %), seguido de tatus (Oasypus novemcinctus, 17%), pacas (Agouti paca, 15%) e veados (Mazama americana eM. gouazoubira, 13%). Os dois gêneros que fornecem a maior porcentagem da carne de caça são os porcos do mato, com 40% do peso total da caça e, os veados, com 27%. Os territórios de caça que são cobertos pelo menos por 60% de floresta fornecem o dobro de carne que outras áreas mais desmatadas com a mesma duração do tempo de caça. Além disso, as espécies caçadas nessas áreas são maiores do que nas outras áreas mais desmatadas. Os caçadores das zonas mais desmatadas necessitam de um tempo maior de caça e apanham espécies menores e mais adaptadas à transformação do meio ambiente. O consumo médio anual de carne de caça foi estimado em 14,7 quilos por pessoa/ano. Comparando este estudo com o realizado na mesma região por Smith (1976), verifica-se que a atividade da caça e o consumo de carne de caça foram constantes durante os últimos 25 anos, apesar da ausência da anta (Tapirus terrestris) nas espécies caçadas em 2000. A agricultura migratória e a produção de gado vêm modificando o habitat dos animais silvestres. As mesmas são, sem dúvida, o fator principal de conversão de ecossistemas florestais, com conseqüências para a perda de biodiversidade e a diminuição do rendimento da caça em áreas de menor cobertura florestal

Efficacité énergétique et émissions de GES de systèmes d'élevage bovin viande en Amazonie.

L?élevage au Brésil, 1er exportateur mondial de viande, serait responsable de plus de 75% des déforestations et 19% des émissions nationales de gaz à effet de serre (GES). L?objectif de notre étude est de mettre au point une première méthode de calcul d?efficacité énergétique et d?émissions de GES des systèmes d?élevage amazoniens, en se basant sur la méthode Planète. Une révision de l?ensemble des coefficients énergétiques et des facteurs d?émission de GES ainsi que l?ajout de certaines rubriques ont permis d?élaborer un logiciel de calcul adapté au contexte régional. Six systèmes d?élevage bovin allaitants ont été étudiés lors d?enquêtes directes : un naisseur, trois engraisseurs et deux naisseurs-engraisseurs avec des troupeaux compris entre 650 et 3700 têtes, des charges instantanées variables, liées à des gestions de pâturage et des pratiques alimentaires très diversifiées. Les consommations d?énergie sont en moyenne de 9 724 MJ/t poids vif/an (min=4 019 MJ/t, max=15 243 MJ/t). Les principaux postes, responsables de 56% à 93% des consommations d?énergie, sont les achats d?aliments, la fertilisation des pâturages et l?achat de carburant (et d?animaux pour les engraisseurs). Ces systèmes d?élevage basés sur des ressources herbagères abondantes, utilisant peu d?intrants et d?infrastructures sont peu consommateurs d?énergie, comparés aux autres systèmes dans le monde. Les différences d?efficacité énergétique sont liées à l?efficacité productive végétale et animale et non au degré d?intensité d?utilisation des intrants. Les émissions de GES sont importantes, en moyenne de 19,8 t eq CO2/ t poids vif/ an (min= 11,2 t eq CO2/t, max= 40,5 t eq CO2/t). La déforestation avec un amortissement linéaire sur 20 ans représente de zéro jusqu?à 75% des émissions totales. Nous avons aussi montré l?intérêt environnemental de systèmes productifs intégrant agriculture et élevage. Ces résultats à l?échelle des exploitations participent de la prise de conscience individuelle des éleveurs et renforcent les engagements locaux pour la « déforestation zéro ». La comparaison avec d?autres systèmes d?élevage dans le monde souligne l?intérêt d?une production animale maitrisée, en matière de déforestation et d?intensification, sous les tropiques humides. Plus largement cette étude montre la validité de cette méthode et devrait permettre de généraliser ces bilans

Subsistence Hunting on a Pioneer Front of Amazonia: Case of Uruará

Although prohibited, hunting is widely practiced by rural populations settled along the Transamazon Highway. A diagnostic of subsistence hunting was conducted in 1997 in the Uruará district of Brazil. Beat, hide and trap were the three main hunting techniques, and each one targeted a specific type of game. Although these techniques were rudimentary, 62% of the hunts were successful. Hunters kept their movements within five kilometers at most from their homes, thus covering an 80 km² area. The number of species caught was low: pacas (Agouti paca), deer (Mazama sp.) and collared peccaries (Tayassu tajacu) provided more than 70% of game meat. The red mazama (Mazama americana), the favorite species, and the paca underwent the highest hunting pressure. In addition to social and ludic roles, hunting had a real nutritional value. Mean daily game meat consumption ranged from 36 to 45.9 g per person (i.e. 13.1–16.7 kg per person per year), depending on the origin of the hunters (urban or rural, respectively). Game hunting did not seem to be the main factor for loss of biodiversity, which might rather result from the transformation of the forest ecosystem into agricultural zones: the habitats were parceled out, generating a reduction in the biodiversity. Community management of wildlife and development of new activities such as breeding of wild animals could help preserve natural resources

Past intensification trajectories of livestock led to mixed social and environmental services

International audienceRecent studies highlighted the multiple positive and negative contributions of livestock to society. Livestock production, through its direct and indirect impacts on land use, is an important driver of services provision. Although a few studies provide an account on the multiple services in different livestock systems, there is still an important knowledge gap on the drivers that contribute to the differentiation of services provisioning across areas. We investigated the hypothesis that the current level of services has derived from the past intensification trajectories of livestock. The objective of this study was to understand the influences of past changes in livestock, land-use and socio-economic variables on the current provision of social, environmental and cultural services by the livestock sector in France. We combined a long-term country-wide database on livestock intensification between 1938 and 2010 and a database on services provisioning in 2010. We used a set of multivariate methods to simultaneously analyse the changes in livestock intensification from 1938 to 2010 and the current level of services provisioning. Our analysis focused on a set of 60 French departments where livestock play a significant economic role in agricultural production. Our study revealed that the provision of services was spatially structured and based on three groups of departments, characterised by different rates of change in intensification variables. In the first group, 'Intensive livestock areas', the high level of employment in the livestock sector was mainly associated with high rates of change in monogastric stocking rates (+1045%) and milk productivity (+451%). In the second group, 'Extensive livestock areas', the high levels of environmental and cultural services were mainly associated with moderate rates of change in herbivores stocking rate (+95%) and the stability of grassland area (+13%). In the third group, 'Transition areas', the low provision of all services was associated with the decline in livestock due to crop expansion. This study provides knowledge to understand how past changes determined the current contribution of livestock areas in providing differentiated bundles of services, which might help steer the development of the current livestock sector towards more sustainable trajectories