Yoko Ishida

James Cook University | JCU · School of Marine & Tropical Biology

OUTLIERS Project (Quantifying The Nature and Significance of Amazon Forest Outliers). Parceria Projeto NORDESTE, Imperial College of London, Instituto Nacional de Pesquisas da Amazônia, Programa de Biodiversidade do Trópico Ecotonal do Nordeste (BIOTEN) e The Royal Society of London. Primeiros Resultados: Ensaio Preliminar (2022) sobre a FLORA da F...

Tropical forests take up more carbon (C) from the atmosphere per annum by photosynthesis than any other type of vegetation. Phosphorus (P) limitations to C uptake are paramount for tropical and subtropical forests around the globe. Yet the generality of photosynthesis-P relationships underlying these limitations are in question, and hence are not r...

Increasing severity and frequency of drought is predicted for large portions of the terrestrial biosphere, with major impacts already documented in wet tropical forests. Using a four-year rainfall exclusion experiment in the Daintree Rainforest in northeast Australia, we examined canopy tree responses to reduced precipitation and soil water availab...

Abstract Road‐infrastructure projects are expanding rapidly worldwide while penetrating into previously undisturbed forests. In Sumatra, Indonesia, a planned 88‐km‐long mining road for transporting coal would imperil the Harapan Forest, the island's largest surviving tract of lowland rainforest. Such roads often lead to increased forest encroachmen...

Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of...

Tropical forests are the most diverse and productive ecosystems on Earth. While better understanding of these forests is critical for our collective future, until quite recently efforts to measure and monitor them have been largely disconnected. Networking is essential to discover the answers to questions that transcend borders and the horizons of...

Aims Anthropogenic climate change is predicted to increase mean temperatures and rainfall seasonality. How tropical rainforest species will respond to this climate change remains uncertain. Here we analyzed the effects of a 4-year experimental throughfall exclusion on an Australian endemic palm (Normambya normanbyi) in the Daintree rainforest of No...

Climate change scenarios predict increasing atmospheric CO 2 concentrations ([CO 2 ]), temperatures and droughts in tropical regions. Individually, the effects of these climate factors on plants are well established, whereas experiments on the interactive effects of a combination of factors are rare. Moreover, how these environmental factors will a...

Bivariate relationships between plant tissue nutrient concentration have largely been studied across broad environmental scales regardless of their covariation with soil and climate. Comparing leaf and branch wood concentrations of C, Ca, K, Mg, N, Na, and P for trees growing in tropical forests in Amazonia and Australia we found that the concentra...

Earth system models (ESMs) use photosynthetic capacity, indexed by the maximum Rubisco carboxylation rate (Vcmax), to simulate carbon assimilation and typically rely on empirical estimates, including an assumed dependence on leaf nitrogen determined from soil fertility. In contrast, new theory, based on biochemical coordination and co‐optimization...

High rates of land conversion and land use change have vastly increased the proportion of secondary forest in the lowland tropics relative to mature forest. As secondary forests recover following abandonment, nitrogen (N) and phosphorus (P) must be present in sufficient quantities to sustain high rates of net primary production and to replenish the...

Increased drought is forecasted for tropical regions, with severe implications for the health and function of forest ecosystems. How mature forest trees will respond to water deficit is poorly known. We investigated wood anatomy and leaf traits in lowland tropical forest trees after 24 months of experimental rainfall exclusion. Sampling sun‐exposed...

The island of New Guinea harbours one of the world’s largest tracts of intact tropical forest, with 41% of its land area in Indonesian Papua (Papua and Papua Barat Provinces). Within Papua, the advent of a 4000-km ‘development corridor’ reflects a national agenda promoting primary-resource extraction and economic integration. Papua, a resource fron...

The necessity to create national to global-scale biodiversity monitoring systems as part of assessing progress toward biodiversity agendas presents a challenge for signatory countries. This is a brief review of ongoing Brazilian national initiatives that would allow the construction of a general biomonitoring network scheme in protected areas; with...

One of the major challenges in ecology is to understand how ecosystems respond to changes in environmental conditions, and how taxonomic and functional diversity mediate these changes. In this study, we use a trait-spectra and individual-based model, to analyse variation in forest primary productivity along a 3.3 km elevation gradient in the Amazon...

Why do forest productivity and biomass decline with elevation? To address this question, research to date generally has focused on correlative approaches describing changes in woody growth and biomass with elevation. We present a novel, mechanistic approach to this question by quantifying the autotrophic carbon budget in 16 forest plots along a 330...

We examined whether variations in photosynthetic capacity are linked to variations in the environment and/or associated leaf traits for tropical moist forests ( TMF s) in the Andes/western Amazon regions of Peru. We compared photosynthetic capacity (maximal rate of carboxylation of Rubisco ( V cmax ), and the maximum rate of electron transport ( J...

Background: Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, th...

Daintree Rainforest Observatory vascular plant species list and stem abundances (≥ 10 cm dbh) within the 2 x 1-ha monitoring plots.

Simulations of photosynthesis by terrestrial biosphere models typically need a specification of the maximum carboxylation rate ( V cmax ). Estimating this parameter using A – C i curves (net photosynthesis, A , vs intercellular CO 2 concentration, C i ) is laborious, which limits availability of V cmax data. However, many multispecies field dataset...

Sampling along a precipitation gradient in tropical South America extending from ca. 0.8 to 2.0 m a−1, savanna soils had consistently lower exchangeable cation concentrations and higher C / N ratios than nearby forest plots. These soil differences were also reflected in canopy averaged leaf traits with savanna trees typically having higher leaf mas...

Fungi are ubiquitous in the atmosphere and may play an important role in atmospheric processes. We investigated the composition and diversity of fungal communities over the Amazon rainforest canopy and compared these communities to fungal communities found in terrestrial environments. We characterized the total fungal community and the metabolicall...

Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multidisciplinary approach, we examined the h...

Understanding how tropical rainforest trees may respond to the precipitation extremes predicted in future climate change scenarios is paramount for their conservation and management. Tree species clearly differ in drought susceptibility, suggesting that variable water transport strategies exist. Using a multi-disciplinary approach, we examined the...

Sampling along a precipitation gradient in tropical America extending from ca. 0.8 to 2.0 m a−1, savanna soils had consistently lower exchangeable cation concentrations and higher C/N ratios than nearby forest plots. These soil differences were also reflected in canopy averaged leaf traits with savanna trees typically having higher leaf mass per un...

Through interpretations of remote-sensing data and/or theoretical propositions, the idea that forest and savanna represent "alternative stable states" is gaining increasing acceptance. Filling an observational gap, we present detailed stratified floristic and structural analyses for forest and savanna stands located mostly within zones of transitio...

Fungi are ubiquitous in the atmosphere and may play an important role in atmospheric processes. We investigated the composition and diversity of fungal communities over the Amazon rainforest canopy and compared these communities to fungal communities 5 found in terrestrial environments. We characterized the total fungal community and the metabolica...

Photosynthesis/nutrient relationships of proximally growing forest and savanna trees were determined in an ecotonal region of Cameroon (Africa). Although area-based foliar N concentrations were typically lower for savanna trees, there was no difference in photosynthetic rates between the two vegetation formation types. Opposite to N, area-based P c...

Leaf dark respiration (Rdark ) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. M...

Variations in leaf mass per unit area (Ma) and foliar concentrations of N, P, C, K, Mg and Ca were determined for 365 trees growing in 23 plots along a precipitation gradient ranging from 0.29 m a-1 to 1.62 m a-1. The transect extended from just south to the Sahara Desert in Mali to the forest-savanna transition zones (ZOT) of Ghana and Cameroon. C...

Background/Question/Methods As an integral part in carbon cycle, photosynthetic capacity has been increasingly incorporated in vegetation-climate models for predicting ecosystem productivity. To predict variations in photosynthetic capacity over large spatial and temporal scales, assumptions are made on the relationship between photosynthetic cap...

Background: Dissolved organic carbon (DOC) is a major component of the total carbon in headstreams in Amazonia. Long-term measurements of DOC concentration are difficult to obtain in remote areas of Amazonia. Aims: To take measurements of electrical conductivity (EC) and DOC concentration in a blackwater stream and to determine whether it is possib...

Background: There is no generally agreed classification scheme for the many different vegetation formation types occurring in the tropics. This hinders cross-continental comparisons and causes confusion as words such as ‘forest’ and ‘savanna’ have different meanings to different people. Tropical vegetation formations are therefore usually imprecise...

The database of the Brazilian Program for Biodiversity Research (PPBio; GIVD ID SA-BR-001) includes data on the environment and biological groups such as plants. It is organized by site, which is usually a grid with 10 to 72 uniformly-distributed plots, and has already surveyed 1,638 relevés across different Brazilian ecosystems. The sampling desig...

The database of the Brazilian Program for Biodiversity Research (PPBio; GIVD ID SA-BR-001) includes data on the environment and biological groups such as plants. It is organized by site, which is usually a grid with 10 to 72 uniformly-distributed plots, and has already surveyed 1,638 relevés across different Brazilian ecosystems. The sampling desig...

Isoprene is emitted from many terrestrial plants at high rates, accounting for an estimated 1/3 of annual global volatile organic compound emissions from all anthropogenic and biogenic sources combined. Through rapid photooxidation reactions in the atmosphere, isoprene is converted to a variety of oxidized hydrocarbons, providing higher order react...

Through rapid reactions with ozone, which can initiate the formation of secondary organic aerosols, the emission of sesquiterpenes from vegetation in Amazonia may have significant impacts on tropospheric chemistry and climate. Little is known, however, about sesquiterpene emissions, transport, and chemistry within plant canopies owing to analytical...

Changes in precipitation in the Amazon Basin resulting from regional deforestation, global warming, and El Niño events may affect emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and nitric oxide (NO) from soils. Changes in soil emissions of radiatively important gases could have feedback implications for regional and global c...

Fires set for slash-and-burn agriculture contribute to the current unsustainable accumulation of atmospheric greenhouse gases, and they also deplete the soil of essential nutrients, which compromises agricultural sustainability at local scales. Integrated assessments of greenhouse gas emissions have compared intensive cropping systems in industrial...

On an average, 18,000 km2 of Brazilian Amazon terra firme forest vegetation is burned every year. Most of this area is replaced by pastures cultivated to support cattle ranching. The replacement of tropical terra firme forests by cultivated pastures, has introduced different species of African C4 tropical grasses, mainly of the genus Brachiaria. Th...

Phosphorus (P) is generally considered the most common limiting nutrient for productivity of mature tropical lowland forests growing on highly weathered soils. It is often assumed that P limitation also applies to young tropical forests, but nitrogen (N) losses during land-use change may alter the stoichiometric balance of nutrient cycling processe...

Here we present the within-site, seasonal, and interannual variations of the carbon (δ13C) and nitrogen (δ15N) isotope ratios of leaves, wood, bark and litter from four sites in the Amazon region, Brazil. Samples were collected in Manaus (3° 06′07″ S; 60°01′30″ W), Ji-Paraná (10°53′07″ S; 61°57′06″ W), and Santarém (2°26′35″ S; 54°42′30″ W) with me...

Understanding secondary successional processes in Amazonian terrestrial ecosystems is becoming increasingly important as continued deforestation expands the area that has become secondary forest, or at least has been through a recent phase of secondary forest growth. Most Amazonian soils are highly weathered and relatively nutrient poor, but the ro...

Understanding secondary successional processes in Amazonian terrestrial ecosystems is becoming increasingly important as continued deforestation expands the area that has become secondary forest, or at least has been through a recent phase of secondary forest growth. Most Amazonian soils are highly weathered and relatively nutrient poor, but the ro...

1] Changes in land-use and climate are likely to alter moisture and substrate availability in tropical forest soils, but quantitative assessment of the role of resource constraints as regulators of soil trace gas fluxes is rather limited. The primary objective of this study was to quantify the effects of moisture and substrate availability on soil...

Changes in precipitation in the Amazon Basin resulting from regional deforestation, global warming, and El Niño events may affect emissions of carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and nitric oxide (NO) from soils. Changes in soil emissions of radiatively important gases could have feedback implications for regional and global c...

To assess the effect of soil flooding and plant submergence on growth, chlorophyll levels and fluorescence emission in Setaria anceps Stapf ex Massey e Paspalum repens Berg, potted plants were disposed in tanks to simulate these conditions during 30 days. The experimental design used was a rand omized complete block with five replications. Seven ev...

Deforestation and global climatic change could result in significant reduction in precipitation in the Amazon Basin. Attendant changes in soil water content may affect emissions of trace gases from soils. A throughfall exclusion experiment was initiated in 2000 at the Tapajos National Forest to investigate the responses of forest biogeochemical pro...

1] Moist tropical forests in Amazonia and elsewhere are subjected to increasingly severe drought episodes through the El Niño–Southern Oscillation (ENSO) and possibly through deforestation-driven reductions in rainfall. The effects of this trend on tropical forest canopy dynamics, emissions of greenhouse gases, and other ecological functions are po...

The objective of this work was to study the effects of waterlogged soil on the stomatal conductance, the relative water content, the chlorophyll content and on the N, P, K and soluble sugar concentrations of leaf, bulb and root tissues of young pijuayo palms (Bactris gasipaes Kunth), Six month old age plants were submitted to flooding by continuous...

O objetivo deste trabalho foi estudar os efeitos do encharcamento do solo sobre a condutância estomática, o conteúdo relativo de água, o teor de clorofila e a concentração de N, P, K e de açúcares solúveis nos tecidos das folhas, bulbos e raízes de pupunheiras (Bactris gasipaes Kunth) jovens. Plantas com seis meses de idade foram submetidas ao alag...