Understanding Brazil’s catastrophic fires : causes, consequences and policy needed to prevent future tragedies

Brazil has experienced unprecedented wildfires in the last decade. Images ofimmense burnt areas or dead animals that failed to escape the 2020 wildfires have shocked the world. To prevent or minimize further similardisasters wemustunderstandthe factors thathave ledto these catastrophic events. The causes and consequences of wildfires entail complex interactions between the biophysical and sociocultural spheres, and suitable management decisions require a sound scientific base. We present the recent panorama of increasing fire outbreaks in the Brazilian biomes, and discuss the causes that have contributed to such fires, their impacts on the environment and overall consequences for human well-being, based on reviewing the extensive specialist literature, on authors’ expert knowledge and information provided by environmental managers, researchers and politicians during a workshop organized to debate the wildfire issue in Brazil. Our up-to-date review is aimed at the academic public, environmental managers and decision- and policy-makers. First, we present evidence on the contrasting effects of fire on different ecosystems. Second, we outline the historic perceptions and policies related to fire use and management in Brazil since its colonization to the present date. Third, we propose means to advance fire prevention and develop successful management strategies. Finally, we answer frequently asked questions to clarify and/or demystify some fire-related issues not always properly addressed in the media

Fecundity, dispersal and predation of seeds of Archontophoenix cunninghamiana H. Wendl. & Drude, an invasive palm in the Atlantic forest

Understanding the basic biology of invasive species can help us to choose the best management strategies to deal with the invasion. I report the phenology, seed production and dispersal of Archontophoenix cunninghamiana, an Australian palm that is invading Atlantic forest fragments. Field work was done in a 10 ha forest fragment (Mata da Cuaso 23º34' S, 46º43' W). Archontophoenix produced bunches of fruits all year round, with a peak of mature fruits from October to February. Trees reach maturity around 18.5 cm DBH, each producing 4,119 ± 1,922 seeds year-1. Birds disperse the seeds, and nearly 15% of them escape post-dispersal seed predation during the time interval needed for germination. The spatial pattern of post-dispersal predation and the absence of pre-dispersal seed predation suggest a lack of specialized seed predators of Archontophoenix, as predicted by the enemy release hypothesis. Data obtained from this and other studies pointed out to a massive increase in seed production of A. cunninghamiana in a few years within the fragment. I suggest that this invasive palm can be taking advantage of the absence of Euterpe edulis Mart., a native palm which has similar biology, and was locally extinct due to human disturbances. Recommendations to control the invasion include the continuous removal of all Archontophoenix larger than 15 cm DBH, and the establishment of a buffer zone free of Archontophoenix around the fragment to decrease propagule pressure.Conhecer a biologia de espécies invasoras pode auxiliar na escolha de estratégias de manejo visando seu controle. Este estudo enfoca a fenologia, produção e dispersão de sementes de Archontophoenix cunninghamiana, uma palmeira nativa da Austrália que está invadindo fragmentos de Mata Atlântica. O estudo foi desenvolvido num fragmento florestal de 10 ha (Mata da Cuaso 23º34' S, 46º43' W). Archontophoenix produziu frutos ao longo do ano, apresentando frutos maduros principalmente de outubro a fevereiro. As árvores atingem a maturidade com 18,5 cm DAP, cada uma produzindo 4.119 ± 1.922 sementes ano-1. Aves dispersam as sementes de Archontophoenix e 15% das sementes sobrevivem a predação pós-dispersão até o tempo requerido para germinação. O padrão espacial de predação pós-dispersão e a ausência de predadores de sementes pré-dispersão sugerem a ausência de predadores de sementes de Archontophoenix especializados, conforme predito pela hipótese de liberação de inimigos naturais. Dados deste e de outros estudos indicam um aumento expressivo na produção de sementes de A. cunninghamiana no fragmento em poucos anos. Archontophoenix pode estar se beneficiando da ausência de Euterpe edulis Mart., uma palmeira nativa que possui biologia similar e que foi extinta localmente devido à ação humana. Recomendações para controlar a invasão incluem a remoção contínua de todos Archontophoenix maiores que 15 cm DAP no fragmento e o estabelecimento de uma zona tampão ao redor do fragmento livre de Archontophoenix para dificultar a chegada de propágulos.587594Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Crop size influences pre-dispersal seed predation in the Brazilian Cerrado

<div><p>ABSTRACT Many pre-dispersal seed predators are specialized insects that rely on seeds for larval development. These insects may respond to the amount of seeds produced by a plant (i.e. crop size), increasing the proportion of seeds damaged with increases in seed numbers. Large seeds have more resources and spend more time in plants to complete their development and are probably more prone to be preyed on by those insects than small seeds. Here I tested how crop size and seed mass influence pre-dispersal seed predation in plants from the Cerrado savannas of Brazil. I related plant crop size to pre-dispersal seed predation for Xylopia aromatica and Erythroxylum pelleterianum. A literature review was performed to test if seed mass may explain among-species differences in pre-dispersal seed predation. Pre-dispersal losses increased proportionally to crop size in the two species investigated, but some species show positive or no density-dependent seed predation in literature, indicating that seed losses are not a simple function of crop sizes. Seed mass did not explain pre-dispersal seed loss differences among 14 species with data available. Pre-dispersal losses are often small and probably less important than seed dispersal and establishment limitation for plant recruitment in Cerrado savannas.</p></div

Potential impact of mammal defaunation on the early regeneration of a large-seeded palm in the Brazilian Atlantic Forest

Defaunation, the decline in animal species and populations, is biased towards large-bodied animals that have unique roles as dispersers of large seeds. However, it is speculated that these roles may still be performed by smaller animals, such as small mammals like rodents and marsupials, that thrive in defaunated sites. We investigated if small mammals can disperse the large-seeded palm Attalea dubia. We performed the study in a well-conserved Atlantic Forest remnant in southeast Brazil that still harbours large mammals, such as tapirs. Focal observations showed that capuchin-monkeys consumed the mesocarp of the fruits and dropped the seeds beneath the plant crown thereafter. Mammals preyed on ca. 1% and removed ca. 15% of the fallen fruit/seed and deposited them up to 15 m away. Amongst them, small mammals (< 1 kg), such as the squirrel Guerlinguetus brasiliensis and non-identified nocturnal Sigmodontinae, as well as the marsupial Philander frenatus performed the bulk of interactions. Dispersal enhances recruitment, but the short distances of seed removal did not match the current spatial distribution of palm seedlings and juveniles. Recaching rates of hoarded seeds were small (2%) and unlikely to increase distances of seed dispersal achieved. Short distances of dispersal would increase plant clumpiness and negative density-dependent effects with time. Although small mammals can provide legitimate dispersal, they cannot fully replace larger frugivorous mammals and maintain long-distance seed dispersal that feeds plant metapopulation dynamics and seed gene flow

Spatial variation in post-dispersal seed removal in an Atlantic forest: Effects of habitat, location and guilds of seed predators

Studies of post-dispersal seed removal in the Neotropics have rarely examined the magnitude of seed removal by different types of granivores. The relative impact of invertebrates, small rodents, and birds on seed removal was investigated in a 2,178 ha Atlantic forest fragment in southeastern Brazil. We used popcorn kernels (Zea mays-Poaceae) to investigate seed removal in a series of selective exclosure treatments in a replicated, paired design experiment that included forest understory, gaps, and forest edge sites. We recorded the vegetation around the experimental seed stations in detail in order to evaluate the influence of microhabitat traits on seed removal. Vertebrate granivores (rodents and birds) were surveyed to determine whether granivore abundance was correlated with seed removal levels. Seed removal varied spatially and in unpredictable ways at the study site. Seed encounter and seed use varied with treatments, but not with habitat type. However, seed removal by invertebrates was negatively correlated with gap-related traits, which suggested an avoidance of large gaps by granivorous ants. The abundance of small mammals was remarkably low, but granivorous birds (tinamous and doves) were abundant at the study site. Birds were the main seed consumers in open treatments, but there was no correlation between local granivorous bird abundance and seed removal. These results emphasize the stochastic spatial pattern of seed removal, and, contrary to previous studies, highlight the importance of birds as seed predators in forest habitats. (c) 2007 Elsevier Masson SAS. All rights reserved

Reproductive phenology, seed removal and early regeneration in relation to distance from parental plants of a native palm in small Atlantic forest fragments

ABSTRACT The Brazilian Atlantic Forest is a global biodiversity hotspot, but most of what remains are small fragments. Small fragments are often harsh environments for forest plant recruitment due to edge effects and the loss of frugivorous animals that provide seed dispersal. We recorded the one-year reproductive phenology of the keystone palm Syagrus romanzoffiana in small (<2.5ha) Atlantic Forest fragments in southeastern Brazil. We tested the Janzen-Connell hypothesis with seed-removal experiments and followed the five-year survival of recruits in relation to the distance from parental plants. Palms produced many fruits throughout the year (mean 2,600/plant). More seedlings were found away from parental plants than near them, thereby supporting the Janzen-Connell hypothesis. Almost 45% of seedlings alive in 2010 were dead five years later, but recruitment of new seedlings compensated for this mortality. Distance-dependent factors influenced the density of early ontogenetic stages, but had limited effects on juveniles or on seed removal. High seed production, seed dispersal provided by disturbance-tolerant frugivores and the relatively long-term survival of adults, seedlings and juveniles seem to allow the persistence of S. romanzoffiana in the forest fragments, but possibly at the cost of an increased clumped distribution and reduced gene flow at the landscape scale

Data from: Fire-sensitive species dominate seed rain in a long unburned Cerrado: implications for plant community diversity and woody encroachment in savannas

Woody encroachment is becoming common in tropical savannas. Seed rain data and seed addition experiments in a long unburned Brazilian savanna indicate that abundant seed rain of fire-sensitive species can surpass limitations to recruitment and lead to woody encroachment. Thus, active fire management may be required to maintain savanna diversity

Vegetation, seed rain and limitation data

This file contains information on aboveground vegetation, seed rain, seed and establishment limitations, per capita seed germination, species traits, and regression results (influence of species traits on limitation values). This study was conducted in a neotropical savanna (Cerrado) in southeast Brazil