Hunter-gatherer impact on European interglacial vegetation: a modelling approach

This article focuses on hunter-gatherer impact on interglacial vegetation in Europe, using a case study from the Early Holocene (9200–8700 BP). We present a novel agent-based model, hereafter referred to as HUMLAND (HUMan impact on LANDscapes), specifically developed to define key factors in continental-level vegetation changes via assessment of differences between pollen-based reconstruction and dynamic global vegetation model output (climate-based vegetation cover). The identified significant difference between these two datasets can be partially explained by the difference in the models themselves, but also by the fact that climate is not the sole factor responsible for vegetation change. Sensitivity analysis of HUMLAND showed that the intensity of anthropogenic vegetation modification mainly depended on three factors: the number of groups present, their preferences for vegetation openness around campsites, and the size of an area impacted by humans. Overall, both climate and human activities had strong impacts on vegetation openness during the study period. Our modelling results support the hypothesis that European ecosystems were strongly shaped by human activities already in the Mesolithic.Horizon 2020(H2020)813904European Prehistor

Comparações florísticas e estruturais entre comunidades de palmeiras em fragmentos de floresta primária e secundária da Área de Proteção Ambiental Raimundo Irineu Serra - Rio Branco, Acre, Brasil

O presente estudo compara a composição e estrutura das comunidades de palmeiras da Área de Proteção Ambiental Raimundo Irineu Serra - APARIS, localizada no perímetro urbano do Município de Rio Branco-Acre. Foram selecionadas três áreas de floresta secundária em estágios sucessionais distintos: 7,5 anos, 27,5 anos, 37,5 anos de idade, e um fragmento de floresta primária. Em cada área foram instaladas cinco parcelas de 20 X 20m, onde foram analisadas a composição florística, estrutura horizontal e estrutura populacional das palmeiras. Foram identificados 1.034 indivíduos, incluídos em 12 gêneros e 19 espécies de palmeiras. A área de floresta primária apresentou maior diversidade. Na análise da estrutura populacional de cada área, comprovamos a existência de uma escassez de plântulas (≤ 50 cm de altura) e adultos reprodutivos. A fragmentação alterou a composição e diminuiu a riqueza e a diversidade de palmeiras na área da APARIS, enquanto, está favorecendo a dominância de certas espécies como A. phalerata.This study compares the composition and structure of palm communities in fragments of secondary and primary forest within the Raimundo Irineu Serra Environmental Protection Area (APARIS), located at the urban perimeter of Rio Branco, Acre. To evaluate the palm communities, we selected secondary forest areas belonging to three distinct successional stages: 7.5 years; 27.5 years, 37.5 years, and a primary forest fragment. In each forest type we installed five 20 x 20 m plots, where we analyzed floristic composition, vegetation structure, and population demography of all palm species (Arecaceae). In all, we identified 1034 palm individuals, including 12 genera, 19 species. Primary forest exhibited the greatest palm diversity. Structural analysis of each area revealed a scarcity of seedlings (≤ 50 cm tall) and reproductive adults. Fragmentation altered the composition and decreased the richness and diversity of palms within the APARIS, while at the same time, favoring the dominance of certain species, such as A. phalerata