ALBERT

Description: Abstract Assessing the persistent impacts of fragmentation on above ground structure of tropical forests is essential to understanding the consequences of land use change for carbon storage and other ecosystem functions. We investigated the influence of edge distance and fragment size on canopy structure, aboveground woody biomass (AGB), and AGB turnover in the Biological Dynamics of Forest Fragments Project (BDFFP) in central Amazon, Brazil, after 22+ years of fragment isolation, by combining canopy variables collected with Portable Canopy profiling lidar and airborne laser scanning surveys with long‐term forest inventories. Forest height decreased by 30% at edges of large fragments (〉 10 ha) and interiors of small fragments (〈 3 ha). In larger fragments, canopy height was reduced up to 40 m from edges. Leaf area density profiles differed near edges: the density of understory vegetation was higher and midstory vegetation lower, consistent with canopy reorganization via increased regeneration of pioneers following post‐fragmentation mortality of large trees. However, canopy openness and leaf area index remained similar to control plots throughout fragments, while canopy spatial heterogeneity was generally lower at edges. AGB stocks and fluxes were positively related to canopy height and negatively related to spatial heterogeneity. Other forest structure variables typically used to assess the ecological impacts of fragmentation (basal area, density of individuals, and density of pioneer trees) were also related to lidar‐derived canopy surface variables. Canopy reorganization through the replacement of edge‐sensitive species by disturbance‐tolerant ones may have mitigated the biomass loss effects due to fragmentation observed in the earlier years of BDFFP. Lidar technology offered novel insights and observational scales for analysis of the ecological impacts of fragmentation on forest structure and function, specifically aboveground biomass storage. This article is protected by copyright. All rights reserved.

Description: In evergreen tropical forests, the extent, magnitude, and controls on photosynthetic seasonality are poorly resolved and inadequately represented in Earth system models. Combining camera observations with ecosystem carbon dioxide fluxes at forests across rainfall gradients in Amazonia, we show that aggregate canopy phenology, not seasonality of climate drivers, is the primary cause of photosynthetic seasonality in these forests. Specifically, synchronization of new leaf growth with dry season litterfall shifts canopy composition toward younger, more light-use efficient leaves, explaining large seasonal increases (~27%) in ecosystem photosynthesis. Coordinated leaf development and demography thus reconcile seemingly disparate observations at different scales and indicate that accounting for leaf-level phenology is critical for accurately simulating ecosystem-scale responses to climate change.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wu, Jin -- Albert, Loren P -- Lopes, Aline P -- Restrepo-Coupe, Natalia -- Hayek, Matthew -- Wiedemann, Kenia T -- Guan, Kaiyu -- Stark, Scott C -- Christoffersen, Bradley -- Prohaska, Neill -- Tavares, Julia V -- Marostica, Suelen -- Kobayashi, Hideki -- Ferreira, Mauricio L -- Campos, Kleber Silva -- da Silva, Rodrigo -- Brando, Paulo M -- Dye, Dennis G -- Huxman, Travis E -- Huete, Alfredo R -- Nelson, Bruce W -- Saleska, Scott R -- New York, N.Y. -- Science. 2016 Feb 26;351(6276):972-6. doi: 10.1126/science.aad5068.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. jinwu@email.arizona.edu saleska@email.arizona.edu. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. ; Brazil's National Institute for Amazon Research (INPA), Manaus, Amazonas, Brazil. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia. ; John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA. ; Department of Natural Resources and Environmental Science, University of Illinois at Urbana Champaign, Urbana, IL 61081, USA. Department of Earth System Science, Stanford University, Stanford, CA 94025, USA. ; Department of Forestry, Michigan State University, East Lansing, MI 48824, USA. ; Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721, USA. Earth and Environmental Sciences Division, Los Alamos National Lab, Los Alamos, NM 87545, USA. ; Department of Environmental Geochemical Cycle Research, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan. ; Centro de Energia Nuclear na Agricultura, University of Sao Paulo, Piracicaba, SP, Brazil. Smart and Intelligent Cities Programme, University Nove de Julho, Sao Paulo, SP, Brazil. ; Department of Environmental Physics, University of Western Para (UFOPA), Santarem, Para, Brazil. ; Instituto de Pesquisa Ambiental da Amazonia (IPAM), Belem, Para, Brazil. Woods Hole Research Center, Falmouth, MA 02450, USA. ; Western Geographic Science Center, U.S. Geological Survey, Flagstaff, AZ 86001, USA. ; Ecology and Evolutionary Biology and Center for Environmental Biology, University of California, Irvine, CA 92629, USA. ; Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26917771" target="_blank"〉PubMed〈/a〉