Pollen analysis of sediment core GIK16415-2 in the eastern tropical Atlantic

Palynological data of the marine core M 16415-2 show latitudinal shifts of the northern fringe of the tropical rain forest in north-west Africa during the last 700 ka. Savanna and dry open forest expanded southwards and tropical rain forest expanded northwards during dry and humid periods, respectively. Until 220 ka B.P., the tropical rain forest probably kept its zonal character in West Africa during glacials and interglacials. It is only during the last two glacial periods that the rain forest possibly fragmented into refugia. Throughout the Brunhes chron, pollen and spore transport was mainly by trade winds.

Encalhes de Cetáceos ocorridos no período de 1984 a 2005 no litoral do Rio Grande do Norte, Brasil

Strandings of live or dead aquatic mammals constitute an important instrument to provide information regarding the occurrence, biology and ecology of these species. The aim of this study was to register the stranded species of cetaceans, the frequency and the spatial-temporal distribution of theses strandings during the period of 1984 to 2005, in the coast of Rio Grande do Norte. Data was acquired through the monitoring of strandings in the north, north-west and south coast of RN, and through information obtained from institutions and newspaper archives of the State. A total of 122 strandings of cetaceans were registered along the coast of Rio Grande do Norte. Of the 14 species of cetaceans registered, four species had higher frequencies: Sotalia guianensis (n= 65), Steno bredanensis (n = 6), Globicephala macrorhynchus (n = 6) and Physeter macrocephalus (n = 7). Out of 118 strandings, 93 occurred in the south coast (78.8 %), 23 in the north coast (19.5%) and 2 (1.7%) in the north-west coast of the State. The highest frequency of strandings occurred during the months of August to March and the maximum number of strandings occurred from 2000 onwards, as a consequence of the intense monitoring of the Pequenos Cetáceos Project in Rio Grande do Norte

Análise da eficiência de indicadores da restauração ecológica em Mata Ripária no Cerrado, Planaltina - DF

Dissertação (mestrado)—Universidade de Brasília, Departamento de Engenharia Florestal, Programa de Pós-Graduação em Ciências Florestasi, 2015.

Dinâmica de uma floresta tropical manejada na Amazônia oriental

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Florestal, 2016.

Encalhes de Cetáceos ocorridos no período de 1984 a 2005 no litoral do Rio Grande do Norte, Brasil

Strandings of live or dead aquatic mammals constitute an important instrument to provide information regarding the occurrence, biology and ecology of these species. The aim of this study was to register the stranded species of cetaceans, the frequency and the spatial-temporal distribution of theses strandings during the period of 1984 to 2005, in the coast of Rio Grande do Norte. Data was acquired through the monitoring of strandings in the north, north-west and south coast of RN, and through information obtained from institutions and newspaper archives of the State. A total of 122 strandings of cetaceans were registered along the coast of Rio Grande do Norte. Of the 14 species of cetaceans registered, four species had higher frequencies: Sotalia guianensis (n= 65), Steno bredanensis (n = 6), Globicephala macrorhynchus (n = 6) and Physeter macrocephalus (n = 7). Out of 118 strandings, 93 occurred in the south coast (78.8 %), 23 in the north coast (19.5%) and 2 (1.7%) in the north-west coast of the State. The highest frequency of strandings occurred during the months of August to March and the maximum number of strandings occurred from 2000 onwards, as a consequence of the intense monitoring of the Pequenos Cetáceos Project in Rio Grande do Norte

Towards an assessment of on-farm niches for improved forages in Sud-Kivu, DR Congo

Inadequate quantity and quality of livestock feed is a persistent constraint to productivity for mixed crop-livestock farming in eastern Democratic Republic of Congo. To assess on-farm niches of improved forages, demonstration trials and participatory on-farm research were conducted in four different sites. Forage legumes included Canavalia brasiliensis (CIAT 17009), Stylosanthes guianensis (CIAT 11995) and Desmodium uncinatum (cv. Silverleaf), while grasses were Guatemala grass (Tripsacum andersonii), Napier grass (Pennisetum purpureum) French Cameroon, and a local Napier line. Within the first six months, forage legumes adapted differently to the four sites with little differences among varieties, while forage grasses displayed higher variability in biomass production among varieties than among sites. Farmers’ ranking largely corresponded to herbage yield from the first cut, preferring Canavalia, Silverleaf desmodium and Napier French Cameroon. Choice of forages and integration into farming systems depended on land availability, soil erosion prevalence and livestock husbandry system. In erosion prone sites, 55–60% of farmers planted grasses on field edges and 16–30% as hedgerows for erosion control. 43% of farmers grew forages as intercrop with food crops such as maize and cassava, pointing to land scarcity. Only in the site with lower land pressure, 71% of farmers grew legumes as pure stand. When land tenure was not secured and livestock freely roaming, 75% of farmers preferred to grow annual forage legumes instead of perennial grasses. Future research should develop robust decision support for spatial and temporal integration of forage technologies into diverse smallholder cropping systems and agro-ecologies.

Changes in the spatial distribution of tree species in a terra firme rain forest in Brazilian Amazonia after logging.

The objective of this paper was to determine changes in the spatial distribution of tree species in a logged compared to an unlogged forest of the Tapajos National Forest in the municipality of Belterra, State of Para, Brazil, over an eight-year period. The distribution pattern was determined for trees> 5 cm dbh and, also, for trees > 30 cm dbh. The relationship (a quadrate method) discussed by McGinnis was selected to be used in this study. Forty-seven percent of species with trees > 5 cm dbh showed clumped distribution in the studied forests. Geissospermwn sericeunz Benth & Hook., Minquartia guianensis Aubl., Poureria bilocularis (H. Winkler) Bachni, Protium guacayantan Cuatrec, Sclerolobium chrysophyllunz Poepp. et Endl. and the Sapotaceae family (9 species) occurred in clumps of small trees (5 cm 5 dbh < 30 cm) and big trees (dbh > 30 cm) in both the logged and undisturbed forest. Trees in all sizes of these species certainly have aggregation characteristics in different light condition's during the whole growth-cycle. Only Sclerolobium cizzysophylltan out of fourteen species that occurred aggregated in all forest conditions was light demanding. The shade-tolerant Lecythis lurida (Miers) Mori and Manilkara huberi (Ducke) Stand!. showed also aggregated distribution for small and big trees in the unlogged forest. An aggregated distribution is not always directly correlated to abundance, considering that most of the clumped species had less than seven trees per hectare.

Matéria orgânica e agregação de um planossolo sob diferentes coberturas florestais.

A qualidade da serapilheira pode alterar a agregação do solo, modificando a dinâmica de transformação e alocação do carbono (C) do solo em diferentes compartimentos. Avaliou-se neste estudo, a estabilidade de agregados e sua relação com características químicas da serapilheira, com o carbono orgânico e a fração leve livre da matéria orgânica, sob três diferentes tipos de cobertura vegetal floresta secundária (FS) e plantios de Mimosa Caesalpinaefolia (PM) e Carapa guianenses (PA) com posterior regeneração natural. Amostras de serapilheira foram caracterizadas quanto aos teores de polifenóis, lignina, suberina, tanino, holocelulose e relação C/N. Coletaram-se amostras de terra em duas profundidades (0-10 e 10-20 cm) para estimativa da agregação através da análise do diâmetro médio ponderado (DMP), diâmetro médio geométrico (DMG) e índice de estabilidade dos agregados (IEA). Subamostras das mesmas profundidades foram ainda caracterizadas quanto aos teores de C e da fração leve livre (FLL). Os maiores teores de suberina e polifenóis da serapilheira, encontrados nas áreas FS e PM, reduziram a velocidade de decomposição dos resíduos no solo o que acarretou maiores teores da FLL em ambas as coberturas. Esses compostos contribuíram para a estabilização do C à fase mineral, pois os maiores teores de C foram encontrados nessas áreas. Essa afirmativa é confirmada pelos valores de DMP, DMG e IEA entre as áreas, que são maiores para as coberturas PM e FS. Os teores de polifenóis e suberina foram determinantes na compartimentação do C e agregação do solo das áreas de FS e PM.

Estoques de carbono e nitrogênio e distribuição das frações húmicas no solo sob diferentes coberturas florestais.

Para avaliar o estoque de carbono (C) e nitrogênio orgânicos (N) e a distribuição das substâncias húmicas (ácido fúlvico (AF), ácido húmico (AH) e humina (HUM)) amostras de terra foram coletadas nas profundidades de 0-5, 5-10, 10-20 e 20-40 cm em áreas de Mimosa caesalpineafolia, Carapa guianenses e em floresta secundária na Floresta Nacional FLONA Mário Xavier, Seropédica, RJ. À área de floresta secundária se devem não apenas os maiores valores de estoque de C e N, mas também das frações AF, AH e HUM; ressalta-se, porém, que os maiores valores de C e N e das subtãncias húmicas, podem ser decorrentes dos maiores teores de argila constatados nesta área. Quanto à distriuição das frações húmicas verificou-se, em todas as áreas, predomínio da fração HUM.