Sensitivity of South American tropical forests to an extreme climate anomaly

The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha −1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected

Spatial pattern of three ornitochorous tree species of a Lowlands Atlantic Rainforest in Southeastern Brazil

Orientador: Flávio Antonio Maës dos SantosTese (doutorado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Muitas espécies arbóreas apresentam distribuição espacial agregada. As dióicas e que ocorrem em baixa densidade geralmente são mais agregadas e geram plântulas que são mais espacialmente associadas às fontes de semente do que as homóicas e as mais densas. Devido a eventos locais de dispersão de sementes, comumente há associação espacial entre adultos, sementes e plântulas. Isto ocorre especialmente entre adultos e sementes, mas nem sempre entre sementes e plântulas. Assim, os processos pós-dispersão também podem ter um efeito na estrutura espacial da população, com mecanismos dependentes de distância e densidade possivelmente reduzindo a agregação da mesma, enquanto a heterogeneidade ambiental geralmente aumenta a agregação. O objetivo deste estudo foi determinar como a densidade das fontes de semente, a dispersão e os processos pós-dispersão influenciam a estrutura espacial de três espécies arbóreas da Floresta Ombrófila Densa de Terras Baixas no litoral norte do estado de São Paulo. Nós amostramos todos os indivíduos das três espécies em duas parcelas de 1 ha cada, identificamos seus estádios ontogenéticos e os mapeamos. Durante dois anos, coletamos mensalmente a chuva de sementes. Por último, avaliamos as plântulas previamente amostradas para determinar se elas haviam morrido, recrutado para estádios ontogenéticos subsequentes ou permanecido no mesmo estádio. Então, comparamos os padrões espaciais da sobrevivência, da taxa de mortalidade e da taxa de recrutamento a seis variáveis preditoras. As sementes e os estádios ontogenéticos das três espécies apresentaram agregação, principalmente em pequenas classes de distância. Não houve um padrão claro da influência da densidade das fontes de semente na estrutura espacial das populações. Os adultos de todas as espécies apresentaram associações espaciais com sementes e plântulas, mas estas estiveram associadas em apenas metade das comparações. A mortalidade das plântulas ocorreu aleatoriamente e não modificou o padrão espacial agregado das populações. Os sobreviventes se localizaram principalmente em áreas com alta densidade inicial de plântulas. As taxas de mortalidade não apresentaram relação com as variáveis preditoras e ocorreram aleatoriamente. O mesmo padrão foi encontrado para as taxas de recrutamento de uma das espécies estudadas, mas outra recrutou mais em áreas com maior área basal da população e maior porcentagem de abertura de dossel, e menos em áreas com maior diferença de altitude. Nossos resultados estão de acordo com outros estudos que mostraram que espécies arbóreas tropicais são geralmente agregadas. No entanto, este padrão não pode ser atribuído à densidade das fontes de semente. Por outro lado, a agregação é explicada pela dispersão, uma vez que adultos ocorrem associados a sementes e plântulas. Os processos pós-dispersão não modificam o padrão espacial das populações após os eventos de mortalidade no estádio de plântula. A sobrevivência é maior em áreas com alta densidade de plântulas, como próximo aos adultos reprodutivos. Porém, não é possível prever onde a mortalidade e o recrutamento ocorrem em maiores taxas no ambiente. De forma geral, parece haver um maior recrutamento perto da planta parental devido à maior abundância de sementes neste local, apesar da baixa sobrevivência das mesmas, como proposto no modelo de recrutamento de HubbellAbstract: Many tree species present an aggregated spatial distribution. Dioecious, low-density species tend to be more aggregated and generate seedlings that are more spatially associated to seed sources than homoecious, high-density species. Due to local seed dispersal, adults, seeds and seedlings are generally spatially associated. This is commonly found for adults and seeds, but not always for seeds and seedlings. Therefore, post-dispersal processes can also affect the spatial structure of the population. Distance and density-dependent mechanisms usually decrease the aggregation of the population through ontogeny, while environmental heterogeneity tends to increase the aggregation through ontogeny. This study aimed at determining how density of seed sources, seed dispersal and post-dispersal processes influence the spatial structure of three tree species of a Lowland Atlantic Rainforest in Southeastern Brazil. We sampled every individual of the three species studied within two 1-ha plots. We also identified its ontogenetic stage and mapped the plants. During two years, we monthly sampled the seed rain. Last, we checked the previously sampled seedlings in order to determine if they had died, recruited to further ontogenetic stages or remained at the same stage. Then, we compared the spatial structure of seedling survival, mortality rates and recruitment rates to six predictor variables. The seeds and the ontogenetic stages of the three species studied were aggregated, especially at small distance classes. The influence of density of seed sources on the spatial structure of the populations was not clear. Adults of all species presented associations with seeds and seedlings, but seeds and seedlings were associated in only half of the comparisons. Seedling mortality occurred randomly and did not modify the aggregated spatial pattern of the populations. Survivals were located especially in areas with higher initial seedling density. Mortality rates were not related to the predictor variables and occurred randomly. The same pattern was found for the recruitment rates of one species, but other recruited more in areas with greater population basal area and higher percentage of canopy opening, and less in areas with greater elevation range. Our results agree with previous studies that showed that tropical tree species are generally aggregated. Nevertheless, this spatial pattern cannot be attributed to density of seed sources. On the other hand, the aggregation is explained by seed dispersal, since adults were always spatially associated to seeds and seedlings. Post-dispersal processes do not modify the spatial pattern of the populations after mortality events during the seedling stage. The chance of surviving is enhanced in areas with higher initial seedling density, such as near reproductive adults. However, it is not possible to predict where mortality and recruitment operate at higher rates in the forest due to idiosyncrasies of the species. Overall, recruitment seems to be higher close to the parent plant because of considerably greater seed abundance there, despite very low seed survival, as proposed in the Hubbell's recruitment modelDoutoradoEcologiaDoutor em Ecologi

ARE CORPORAL ALLOMETRIC MEASUREMENTS GOOD PREDICTORS of PALATABILITY IN NEOTROPICAL BUTTERFLIES (LEPIDOPTERA)?

Since palatable butterflies are more dependent on evasive flight to escape from predators, they should be more restricted in their flight-related morphology than unpalatable ones. We compared: the ratios between the (1) length of head plus thorax and the length of abdomen (A/B), (2) length of the tip of the head to wing base and the length of the wing base to end of the abdomen (C/D), (3) the variances of A/B and C/D, (4) the proportion between the thoracic and the body weight, and (5) the flight speed between palatable and unpalatable butterflies. A/B and thoracic/body weight were higher for palatable species, indicating higher body symmetry and muscular mass. However, flight speed did not differ. Unexpectedly, the variance of A/B was higher for palatable species while that of C/D did not differ. Therefore, corporal allometric measurements of Neotropical butterflies are good predictors of palatability, though not of flight speed

Sensitivity of South American tropical forests to an extreme climate anomaly

NERC Knowledge Exchange Fellowship (NE/V018760/1) to E.N.H.C.The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha−1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected.Publisher PDFPeer reviewe

Sensitivity of South American tropical forests to an extreme climate anomaly

Abstract: The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha−1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected

Sensitivity of South American tropical forests to an extreme climate anomaly

Funder: A Moore Foundation grant, Royal Society Global Challenges grant (Sensitivity of Tropical Forest Ecosystem Services to Climate Changes), CNPq grants (441282/2016-4, 403764/2012-2 and 558244/2009-2), FAPEAM grants 1600/2006, 465/2010 and PPFOR 147/2015, CNPq grants 473308/2009-6 and 558320/2009-0. European Research Council (ERC Advanced Grant 291585 – ‘T-FORCES’), the Gordon and Betty Moore Foundation (#1656 ‘RAINFOR’, and ‘MonANPeru’), the European Union’s Fifth, Sixth and Seventh Framework Programme (EVK2-CT-1999-00023 – ‘CARBONSINK-LBA’, 283080 – ‘GEOCARBON’, 282664 – ‘AMAZALERT), the Natural Environment Research Council (NE/ D005590/1 – ‘TROBIT’, NE/F005806/1 – ‘AMAZONICA’, E/M0022021/1 - ‘PPFOR’), several NERC Urgency and New Investigators Grants, the NERC/State of São Paulo Research Foundation (FAPESP) consortium grants ‘BIO-RED’ (NE/N012542/1), ‘ECOFOR’ (NE/K016431/1, 2012/51872-5, 2012/51509-8), ‘ARBOLES’ (NE/S011811/1, FAPESP 2018/15001-6), ‘SEOSAW’ (NE/P008755/1), ‘SECO’ (NE/T01279X/1), Brazilian National Research Council (PELD/CNPq 403710/2012-0), the Royal Society (University Research Fellowships and Global challenges Awards) (ICA/R1/180100 - ‘FORAMA’), the National Geographic Society, US National Science Foundation (DEB 1754647) and Colombia’s Colciencias. We thank the National Council for Science and Technology Development of Brazil (CNPq) for support to the Cerrado/Amazonia Transition Long-Term Ecology Project (PELD/441244/2016-5), the PPBio Phytogeography of Amazonia/Cerrado Transition Project (CNPq/PPBio/457602/2012-0), PELD-RAS (CNPq, Process 441659/2016-0), RESFLORA (Process 420254/2018-8), Synergize (Process 442354/2019-3), the Empresa Brasileira de Pesquisa Agropecuária – Embrapa (SEG: 02.08.06.005.00), the Fundação de Amparo à Pesquisa do Estado de São Paulo – FAPESP (2012/51509-8 and 2012/51872-5), the Goiás Research Foundation (FAPEG/PELD: 2017/10267000329) the EcoSpace Project (CNPq 459941/2014-3) and several PVE and Productivity Grants. We also thank the “Investissement d’Avenir” program (CEBA, ref. ANR-10LABX-25-01), the São Paulo Research Foundation (FAPESP 03/12595-7) and the Sustainable Landscapes Brazil Project (through Brazilian Agricultural Research Corporation (EMBRAPA), the US Forest Service, USAID, and the US Department of State) for supporting plot inventories in the Atlantic Forest sites in Sao Paulo, Brazil. L.E.O.C.A. was supported by CNPq (processes 305054/2016-3 and 442371/2019-5). We thank to the National Council for Technological and Scientific Development (CNPq) for the financial support of the PELD project (441244/2016-5, 441572/2020-0) and FAPEMAT (0346321/2021). NE/B503384/1, NE/N012542/1 - ‘BIO-RED’, ERC Advanced Grant 291585 - ‘T-FORCES’, NE/F005806/1 - ‘AMAZONICA’, NE/N004655/1 - ‘TREMOR’, NERC New Investigators Awards, the Gordon and Betty Moore Foundation (‘RAINFOR’, ‘MonANPeru’), ERC Starter Grant 758873 -‘TreeMort’, EU Framework 6, a Royal Society University Research Fellowship, and a Leverhulme Trust Research Fellowship.The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha−1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected

Sensitivity of South American tropical forests to an extreme climate anomaly

Funder: A Moore Foundation grant, Royal Society Global Challenges grant (Sensitivity of Tropical Forest Ecosystem Services to Climate Changes), CNPq grants (441282/2016-4, 403764/2012-2 and 558244/2009-2), FAPEAM grants 1600/2006, 465/2010 and PPFOR 147/2015, CNPq grants 473308/2009-6 and 558320/2009-0. European Research Council (ERC Advanced Grant 291585 - 'T-FORCES'), the Gordon and Betty Moore Foundation (#1656 'RAINFOR', and 'MonANPeru'), the European Union's Fifth, Sixth and Seventh Framework Programme (EVK2-CT-1999-00023 - 'CARBONSINK-LBA', 283080 - 'GEOCARBON', 282664 - 'AMAZALERT), the Natural Environment Research Council (NE/ D005590/1 - 'TROBIT', NE/F005806/1 - 'AMAZONICA', E/M0022021/1 - 'PPFOR'), several NERC Urgency and New Investigators Grants, the NERC/State of Sao Paulo Research Foundation (FAPESP) consortium grants 'BIO-RED' (NE/N012542/1), 'ECOFOR' (NE/K016431/1, 2012/51872-5, 2012/51509-8), 'ARBOLES' (NE/S011811/1, FAPESP 2018/15001-6), 'SEOSAW' (NE/P008755/1), 'SECO' (NE/T01279X/1), Brazilian National Research Council (PELD/CNPq 403710/2012-0), the Royal Society (University Research Fellowships and Global challenges Awards) (ICA/R1/180100 - 'FORAMA'), the National Geographic Society, US National Science Foundation (DEB 1754647) and Colombia's Colciencias. We thank the National Council for Science and Technology Development of Brazil (CNPq) for support to the Cerrado/Amazonia Transition Long-Term Ecology Project (PELD/441244/2016-5), the PPBio Phytogeography of Amazonia/Cerrado Transition Project (CNPq/PPBio/457602/2012-0), PELD-RAS (CNPq, Process 441659/2016-0), RESFLORA (Process 420254/2018-8), Synergize (Process 442354/2019-3), the Empresa Brasileira de Pesquisa Agropecuaria - Embrapa (SEG: 02.08.06.005.00), the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo - FAPESP (2012/51509-8 and 2012/51872-5), the Goias Research Foundation (FAPEG/PELD: 2017/10267000329) the EcoSpace Project (CNPq 459941/2014-3) and several PVE and Productivity Grants. We also thank the "Investissement d'Avenir" program (CEBA, ref. ANR-10LABX-25-01), the Sao Paulo Research Foundation (FAPESP 03/12595-7) and the Sustainable Landscapes Brazil Project (through Brazilian Agricultural Research Corporation (EMBRAPA), the US Forest Service, USAID, and the US Department of State) for supporting plot inventories in the Atlantic Forest sites in Sao Paulo, Brazil. L.E.O.C.A. was supported by CNPq (processes 305054/2016-3 and 442371/2019-5). We thank to the National Council for Technological and Scientific Development (CNPq) for the financial support of the PELD project (441244/2016-5, 441572/2020-0) and FAPEMAT (0346321/2021). NE/B503384/1, NE/N012542/1 - 'BIO-RED', ERC Advanced Grant 291585 - 'T-FORCES', NE/F005806/1 - 'AMAZONICA', NE/N004655/1 - 'TREMOR', NERC New Investigators Awards, the Gordon and Betty Moore Foundation ('RAINFOR', 'MonANPeru'), ERC Starter Grant 758873 -'TreeMort', EU Framework 6, a Royal Society University Research Fellowship, and a Leverhulme Trust Research Fellowship.AbstractThe tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha−1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected.</jats:p