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Fulltext Multigene phylogeny and morphological descriptions of five species of Agaricus sect. Minores from subtropical climate zones of Pakistan

Bashir H, Asif M, Ghafoor A, Niazi AR, Khalid AN, Parveen G, et al.

PLoS One, 2024;19(7):e0302222.
PMID: 38990811 DOI: 10.1371/journal.pone.0302222

The genus Agaricus includes more than 500 species mostly containing the edible and cultivated species worldwide. As part of the ongoing studies on the biodiversity of genus Agaricus in Pakistan, our objective was to focus on A. sect. Minores which is the largest section of the genus. In the first phylogenetic analyses based on the ITS region of the nuclear ribosomal DNA, our sample included specimens of 97 named species, 27 unnamed species, and 31 specimens (29 newly generated sequences in this study) from subtropical climate zones of Pakistan that likely belong to this section based on their morphology. The 31 specimens grouped into five distinct, well-supported clades corresponding to five species: A. glabriusculus already known from Pakistan and India, A. robustulus first recorded from Pakistan and briefly described here but already known from Bénin, Malaysia, China, and Thailand, and three possibly endemic new species described in detail A. badiosquamulosus sp. nov., A. dunensis sp. nov., and A. violaceopunctatus sp. nov. The sixth species currently known in Pakistan, including A. latiumbonatus also found in Thailand, were included in a multigene tree based on ITS, LSU, and Tef-1α sequence data. They all belong to a large pantropical paraphyletic group while most temperate species belong to a distinct clade, which includes about half of the species of the section. The current study aims to propose three novel species of genus Agaricus based on comprehensive morphological as well as molecular phylogenetic evidences from Pakistan.

Matched MeSH terms: Tropical Climate
The role of economic complexity in the environmental Kuznets curve of MINT economies: evidence from method of moments quantile regression

Adebayo TS, Rjoub H, Akadiri SS, Oladipupo SD, Sharif A, Adeshola I

Environ Sci Pollut Res Int, 2022 Apr;29(16):24248-24260.
PMID: 34822076 DOI: 10.1007/s11356-021-17524-0

In the face of mounting climate change challenges, reducing emissions has emerged as a key driver of environmental sustainability and sustainable growth. Despite the fact that research has been conducted on the environmental Kuznets curve (EKC), few researchers have analyzed this in the light of economic complexity. Thus, the current research assesses the effect of economic complexity on CO2 emissions in the MINT nations while taking into account the role of financial development, economic growth, and energy consumption for the period between 1990 and 2018. Using the novel method of moments quantile regression (MMQR) with fixed effects, an inverted U-shape interrelationship is found between economic growth and CO2 emissions, thus validating the EKC hypothesis. Energy consumption and economic complexity increase CO2 emissions significantly from the 1st to 9th quantiles. Furthermore, there is no significant interconnection between financial development and CO2 emissions across all quantiles (1st to 9th). The outcomes of the causality test reveal a feedback causal connection between economic growth and CO2, while a unidirectional causality is established from economic complexity and energy use to CO2 emissions in the MINT nations. Based on the findings, we believe that governments should stimulate the financial sector to provide domestic credit facilities to industrialists, investors, and other business enterprises on more favorable terms so that innovative technologies for environmental protection can be implemented with other policy recommendations.

Matched MeSH terms: Climate Change
Polyethylene degradation and heavy metals leaching under realistic tropical marine climate

Tan E, Ong MC, Mohd Zanuri NB

Mar Environ Res, 2023 Oct;191:106113.
PMID: 37619477 DOI: 10.1016/j.marenvres.2023.106113

The study examines the influence of temperature and pH on the leaching of six heavy metals (HMs) species: aluminum (Al), zinc (Zn), chromium (Cr), copper (Cu), lead (Pb) and arsenic (As) from transparent polyethylene pellets into seawater. The idea is to understand the potential influence of intensifying global warming and ocean acidification towards microplastic toxicity in the ocean. HMs leaching was obvious by 24th hours, with most HMs concentration decreased in water by 120th and 240th hours except Al. Nevertheless, we report that temperature and pH do not influence the overall HMs leaching from PE pellets with statistical analysis showing no significance (p

Matched MeSH terms: Tropical Climate
Fulltext Environmental impact assessment of rice mill waste valorisation to glucose through biorefinery platform

Abu-Bakar NA, Roslan AM, Hassan MA, Rahman MHA, Ibrahim KN, Abd Rahman MD, et al.

Sci Rep, 2023 Sep 07;13(1):14767.
PMID: 37679379 DOI: 10.1038/s41598-023-28487-2

Environmental impact assessment of glucose production from paddy milling waste, known as empty and partially filled paddy grain (EPFG) in Malaysia, was performed using life cycle assessment (LCA). Three scenarios were conducted based on system expansion of the process. The LCA was conducted using ReCiPe methodology at midpoint and endpoint levels. The results indicate that enzymatic hydrolysis phase is the hotspot in the conversion system due to enzyme production. In addition, the agriculture phase also contributed to negative impacts, especially towards climate change. An improved environmental load was observed in scenario 2 when all EPFG fractionation was utilised to replace fossil-based electricity. Sensitivity analysis showed an increase in glucose yield leads to reduced environmental impact. Thus, the LCA study suggests that the conversion process of EPFG could further benefit and improve the paddy industry waste management with low impact contribution to the environment compared to other feedstock used for glucose production.

Matched MeSH terms: Climate Change
Assessing urban flooding risk in response to climate change and urbanization based on shared socio-economic pathways

Wang M, Fu X, Zhang D, Chen F, Liu M, Zhou S, et al.

Sci Total Environ, 2023 Jul 01;880:163470.
PMID: 37076008 DOI: 10.1016/j.scitotenv.2023.163470

Global climate change and rapid urbanization, mainly driven by anthropogenic activities, lead to urban flood vulnerability and uncertainty in sustainable stormwater management. This study projected the temporal and spatial variation in urban flood susceptibility during the period 2020-2050 on the basis of shared socioeconomic pathways (SSPs). A case study in Guangdong-Hong Kong-Macao Greater Bay Area (GBA) was conducted for verifying the feasibility and applicability of this approach. GBA is predicted to encounter the increase in extreme precipitation with high intensity and frequency, along with rapid expansion of constructed areas, resulting in exacerbating of urban flood susceptibility. The areas with medium and high flood susceptibility will be expected to increase continuously from 2020 to 2050, by 9.5 %, 12.0 %, and 14.4 % under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. In terms of the assessment of spatial-temporal flooding pattern, the areas with high flood susceptibility are overlapped with that in the populated urban center in GBA, surrounding the existing risk areas, which is consistent with the tendency of construction land expansion. The approach in the present study will provide comprehensive insights into the reliable and accurate assessment of urban flooding susceptibility in response to climate change and urbanization.

Matched MeSH terms: Climate Change
Contributions of climate change and human activities to grassland degradation and improvement from 2001 to 2020 in Zhaosu County, China

Zhang M, Zhang F, Guo L, Dong P, Cheng C, Kumar P, et al.

J Environ Manage, 2023 Dec 15;348:119465.
PMID: 37924697 DOI: 10.1016/j.jenvman.2023.119465

Grassland degradation poses a serious threat to biodiversity, ecosystem services, and human well-being. In this study, we investigated grassland degradation in Zhaosu County, China, between 2001 and 2020, and analyzed the impacts of climate change and human activities using the Miami model. The actual net primary productivity (ANPP) obtained with CASA (Carnegie-Ames-Stanford Approach) modeling, showed a decreasing trend, reflecting the significant degradation that the grasslands in Zhaosu County have experienced in the past 20 years. Grassland degradation was found to be highest in 2018, while the degraded area continuously decreased in the last 3 years (2018-2020). Climatic factors for found to be the dominant factor affecting grassland degradation, particularly the decrease in precipitation. On the other hand, human activities were found to be the main factor affecting improvement of grasslands, especially in recent years. This finding profoundly elucidates the underlying causes of grassland degradation and improvement and helps implement ecological conservation and restoration measures. From a practical perspective, the research results provide an important reference for the formulation of policies and management strategies for sustainable land use.

Matched MeSH terms: Climate Change
An evaluation framework for quantifying vegetation loss and recovery in response to meteorological drought based on SPEI and NDVI

Wu C, Zhong L, Yeh PJ, Gong Z, Lv W, Chen B, et al.

Sci Total Environ, 2024 Jan 01;906:167632.
PMID: 37806579 DOI: 10.1016/j.scitotenv.2023.167632

Drought affects vegetation growth to a large extent. Understanding the dynamic changes of vegetation during drought is of great significance for agricultural and ecological management and climate change adaptation. The relations between vegetation and drought have been widely investigated, but how vegetation loss and restoration in response to drought remains unclear. Using the standardized precipitation evapotranspiration index (SPEI) and the normalized difference vegetation index (NDVI) data, this study developed an evaluation framework for exploring the responses of vegetation loss and recovery to meteorological drought, and applied it to the humid subtropical Pearl River basin (PRB) in southern China for estimating the loss and recovery of three vegetation types (forest, grassland, cropland) during drought using the observed NDVI changes. Results indicate that vegetation is more sensitive to drought in high-elevation areas (lag time 8 months). Vegetation loss (especially in cropland) is found to be more sensitive to drought duration than drought severity and peak. No obvious linear relationship between drought intensity and the extent of vegetation loss is found. Regardless of the intensity, drought can cause the largest probability of mild loss of vegetation, followed by moderate loss, and the least probability of severe loss. Large spatial variability in the probability of vegetation loss and recovery time is found over the study domain, with a higher probability (up to 50 %) of drought-induced vegetation loss and a longer recovery time (>7 months) mostly in the high-elevation areas. Further analysis suggests that forest shows higher but cropland shows lower drought resistance than other vegetation types, and grassland requires a shorter recovery time (4.2-month) after loss than forest (5.1-month) and cropland (4.8-month).

Matched MeSH terms: Climate Change
A new automated stem CO2 efflux chamber based on industrial ultra-low-cost sensors

Brändle J, Kunert N

Tree Physiol, 2019 12 01;39(12):1975-1983.
PMID: 31631217 DOI: 10.1093/treephys/tpz104

Tree autotrophic respiratory processes, especially stem respiration or stem CO2 efflux (Estem), are important components of the forest carbon budget. Despite efforts to investigate the controlling processes of Estem in recent years, a considerable lack in our knowledge remains on the abiotic and biotic drivers affecting Estem dynamics. It has been strongly advocated that long-term measurements would shed light onto those processes. The expensive scientific instruments needed to measure gas exchange have prevented Estem measurements from being applied on a larger temporal and spatial scale. Here, we present an automated closed dynamic chamber system based on inexpensive and industrially broadly applied CO2 sensors, reducing the costs for the sensing system to a minimum. The CO2 sensor was cross-calibrated with a commonly used gas exchange system in the laboratory and in the field, and we found very good accordance of these sensors. We tested the system under harsh tropical climatic conditions, characterized by heavy tropical rainfall events, extreme humidity and temperatures, in a moist lowland forest in Malaysia. We recorded Estem of three Dyera costulata (Miq.) trees with our prototype over various days. The variation of Estem was large among the three tree individuals and varied by 7.5-fold. However, clear diurnal changes in Estem were present in all three tree individuals. One tree showed high diurnal variation in Estem, and the relationship between Estem and temperature was characterized by a strong hysteresis. The large variations found within one single tree species highlight the importance of continuous measurement to quantify ecosystem carbon fluxes.

Matched MeSH terms: Tropical Climate
Seaweed and climate change: A mapping review

Segaran TC, Azra MN, Handayani KS, Lananan F, Xu J

Mar Environ Res, 2023 Nov;192:106216.
PMID: 37891025 DOI: 10.1016/j.marenvres.2023.106216

Seaweed has garnered increasing interest due to its capacity to mitigate climate change by curbing carbon emissions from agriculture, as well as its potential to serve as a supplement or alternative for dietary, livestock feed, or fuel source production. Moreover, seaweed is regarded as one of the earliest plant forms to have evolved on Earth. Owing to the extensive body of literature available and the uncertainty surrounding the future trajectory of seaweed research under evolving climate conditions, this review scrutinizes the structure, dynamics, and progression of the literature pertaining to seaweed and climate change. This analysis is grounded in the Web of Science Core Collection database, augmented by CiteSpace software. Furthermore, we discuss the productivity and influence of individual researchers, research organizations, countries, and scientific journals. To date, there have been 8047 articles published globally (after a series of filters and exclusions), with a notable upswing in publication frequency since 2018. The USA, China, and Australia are among the leading countries contributing to this research area. Our findings reveal that current research on seaweed and climate change encompasses 13 distinct research clusters, including "marine heatwave", "temperate estuary", "ocean acidification", and "macroalgal bloom". The most frequently cited keywords are "climate change", "biomass", "community", and "photosynthesis". The seaweed species most commonly referenced in relation to climate change include Gracilaria sp., Sargassum sp., Ecklonia maxima, and Macrocystis pyrifera. These results provide valuable guidance for shaping the direction of specialized topics concerning marine biodiversity under shifting climate conditions. We propose that seaweed production may be compromised during prolonged episodes of reduced water availability, emphasizing the need to formulate strategies to guarantee its continued viability. This article offers fresh perspectives on the analysis of seaweed research in the context of impending climate change.

Matched MeSH terms: Climate Change
Fulltext Demographic consequences of heterogeneity in conspecific density dependence among mast-fruiting tropical trees

O'Brien MJ, Hector A, Kellenberger RT, Maycock CR, Ong R, Philipson CD, et al.

Proc Biol Sci, 2022 Jun 08;289(1976):20220739.
PMID: 35703055 DOI: 10.1098/rspb.2022.0739

The role of conspecific density dependence (CDD) in the maintenance of species richness is a central focus of tropical forest ecology. However, tests of CDD often ignore the integrated effects of CDD over multiple life stages and their long-term impacts on population demography. We combined a 10-year time series of seed production, seedling recruitment and sapling and tree demography of three dominant Southeast Asian tree species that adopt a mast-fruiting phenology. We used these data to construct individual-based models that examine the effects of CDD on population growth rates (λ) across life-history stages. Recruitment was driven by positive CDD for all species, supporting the predator satiation hypothesis, while negative CDD affected seedling and sapling growth of two species, significantly reducing λ. This negative CDD on juvenile growth overshadowed the positive CDD of recruitment, suggesting the cumulative effects of CDD during seedling and sapling development has greater importance than the positive CDD during infrequent masting events. Overall, CDD varied among positive, neutral and negative effects across life-history stages for all species, suggesting that assessments of CDD on transitions between just two stages (e.g. seeds seedlings or juveniles mature trees) probably misrepresent the importance of CDD on population growth and stability.

Matched MeSH terms: Tropical Climate
Fulltext A Deep Learning Approach for Dengue Fever Prediction in Malaysia Using LSTM with Spatial Attention

Majeed MA, Shafri HZM, Zulkafli Z, Wayayok A

Int J Environ Res Public Health, 2023 Feb 25;20(5).
PMID: 36901139 DOI: 10.3390/ijerph20054130

This research aims to predict dengue fever cases in Malaysia using machine learning techniques. A dataset consisting of weekly dengue cases at the state level in Malaysia from 2010 to 2016 was obtained from the Malaysia Open Data website and includes variables such as climate, geography, and demographics. Six different long short-term memory (LSTM) models were developed and compared for dengue prediction in Malaysia: LSTM, stacked LSTM (S-LSTM), LSTM with temporal attention (TA-LSTM), S-LSTM with temporal attention (STA-LSTM), LSTM with spatial attention (SA-LSTM), and S-LSTM with spatial attention (SSA-LSTM). The models were trained and evaluated on a dataset of monthly dengue cases in Malaysia from 2010 to 2016, with the task of predicting the number of dengue cases based on various climate, topographic, demographic, and land-use variables. The SSA-LSTM model, which used both stacked LSTM layers and spatial attention, performed the best, with an average root mean squared error (RMSE) of 3.17 across all lookback periods. When compared to three benchmark models (SVM, DT, ANN), the SSA-LSTM model had a significantly lower average RMSE. The SSA-LSTM model also performed well in different states in Malaysia, with RMSE values ranging from 2.91 to 4.55. When comparing temporal and spatial attention models, the spatial models generally performed better at predicting dengue cases. The SSA-LSTM model was also found to perform well at different prediction horizons, with the lowest RMSE at 4- and 5-month lookback periods. Overall, the results suggest that the SSA-LSTM model is effective at predicting dengue cases in Malaysia.

Matched MeSH terms: Climate
Fulltext Tiger sharks support the characterization of the world's largest seagrass ecosystem

Gallagher AJ, Brownscombe JW, Alsudairy NA, Casagrande AB, Fu C, Harding L, et al.

Nat Commun, 2022 Nov 01;13(1):6328.
PMID: 36319621 DOI: 10.1038/s41467-022-33926-1

Seagrass conservation is critical for mitigating climate change due to the large stocks of carbon they sequester in the seafloor. However, effective conservation and its potential to provide nature-based solutions to climate change is hindered by major uncertainties regarding seagrass extent and distribution. Here, we describe the characterization of the world's largest seagrass ecosystem, located in The Bahamas. We integrate existing spatial estimates with an updated empirical remote sensing product and perform extensive ground-truthing of seafloor with 2,542 diver surveys across remote sensing tiles. We also leverage seafloor assessments and movement data obtained from instrument-equipped tiger sharks, which have strong fidelity to seagrass ecosystems, to augment and further validate predictions. We report a consensus area of at least 66,000 km2 and up to 92,000 km2 of seagrass habitat across The Bahamas Banks. Sediment core analysis of stored organic carbon further confirmed the global relevance of the blue carbon stock in this ecosystem. Data from tiger sharks proved important in supporting mapping and ground-truthing remote sensing estimates. This work provides evidence of major knowledge gaps in the ocean ecosystem, the benefits in partnering with marine animals to address these gaps, and underscores support for rapid protection of oceanic carbon sinks.

Matched MeSH terms: Climate Change
Fulltext Divergence of hydraulic traits among tropical forest trees across topographic and vertical environment gradients in Borneo

Bittencourt PRL, Bartholomew DC, Banin LF, Bin Suis MAF, Nilus R, Burslem DFRP, et al.

New Phytol, 2022 Sep;235(6):2183-2198.
PMID: 35633119 DOI: 10.1111/nph.18280

Fine-scale topographic-edaphic gradients are common in tropical forests and drive species spatial turnover and marked changes in forest structure and function. We evaluate how hydraulic traits of tropical tree species relate to vertical and horizontal spatial niche specialization along such a gradient. Along a topographic-edaphic gradient with uniform climate in Borneo, we measured six key hydraulic traits in 156 individuals of differing heights in 13 species of Dipterocarpaceae. We investigated how hydraulic traits relate to habitat, tree height and their interaction on this gradient. Embolism resistance increased in trees on sandy soils but did not vary with tree height. By contrast, water transport capacity increased on sandier soils and with increasing tree height. Habitat and height only interact for hydraulic efficiency, with slope for height changing from positive to negative from the clay-rich to the sandier soil. Habitat type influenced trait-trait relationships for all traits except wood density. Our data reveal that variation in the hydraulic traits of dipterocarps is driven by a combination of topographic-edaphic conditions, tree height and taxonomic identity. Our work indicates that hydraulic traits play a significant role in shaping forest structure across topographic-edaphic and vertical gradients and may contribute to niche specialization among dipterocarp species.

Matched MeSH terms: Tropical Climate
Fulltext Widespread ancient whole-genome duplications in Malpighiales coincide with Eocene global climatic upheaval

Cai L, Xi Z, Amorim AM, Sugumaran M, Rest JS, Liu L, et al.

New Phytol, 2019 Jan;221(1):565-576.
PMID: 30030969 DOI: 10.1111/nph.15357

Whole-genome duplications (WGDs) are widespread and prevalent in vascular plants and frequently coincide with major episodes of global and climatic upheaval, including the mass extinction at the Cretaceous-Tertiary boundary (c. 65 Ma) and during more recent periods of global aridification in the Miocene (c. 10-5 Ma). Here, we explore WGDs in the diverse flowering plant clade Malpighiales. Using transcriptomes and complete genomes from 42 species, we applied a multipronged phylogenomic pipeline to identify, locate, and determine the age of WGDs in Malpighiales using three means of inference: distributions of synonymous substitutions per synonymous site (Ks ) among paralogs, phylogenomic (gene tree) reconciliation, and a likelihood-based gene-count method. We conservatively identify 22 ancient WGDs, widely distributed across Malpighiales subclades. Importantly, these events are clustered around the Eocene-Paleocene transition (c. 54 Ma), during which time the planet was warmer and wetter than any period in the Cenozoic. These results establish that the Eocene Climatic Optimum likely represents a previously unrecognized period of prolific WGDs in plants, and lends further support to the hypothesis that polyploidization promotes adaptation and enhances plant survival during episodes of global change, especially for tropical organisms like Malpighiales, which have tight thermal tolerances.

Matched MeSH terms: Climate
Fulltext Updates in Air Pollution: Current Research and Future Challenges

Vilcins D, Christofferson RC, Yoon JH, Nazli SN, Sly PD, Cormier SA, et al.

Ann Glob Health, 2024;90(1):9.
PMID: 38312715 DOI: 10.5334/aogh.4363

BACKGROUND: The United Nations has declared that humans have a right to clean air. Despite this, many deaths and disability-adjusted life years are attributed to air pollution exposure each year. We face both challenges to air quality and opportunities to improve, but several areas need to be addressed with urgency.
OBJECTIVE: This paper summarises the recent research presented at the Pacific Basin Consortium for Environment and Health Symposium and focuses on three key areas of air pollution that are important to human health and require more research.
FINDINGS AND CONCLUSION: Indoor spaces are commonly places of exposure to poor air quality and are difficult to monitor and regulate. Global climate change risks worsening air quality in a bi-directional fashion. The rising use of electric vehicles may offer opportunities to improve air quality, but it also presents new challenges. Government policies and initiatives could lead to improved air and environmental justice. Several populations, such as older people and children, face increased harm from air pollution and should become priority groups for action.

Matched MeSH terms: Climate Change
A review of the management of water resources in Malaysia facing climate change

Fulazzaky MA, Syafiuddin A, Muda K, Martin AY, Yusop Z, Ghani NHA

Environ Sci Pollut Res Int, 2023 Dec;30(58):121865-121880.
PMID: 37962755 DOI: 10.1007/s11356-023-30967-x

This paper reviewed the impacts of climate change on the management of the water sector in Malaysia discussing the current status of water resources, water service, and water-related disasters. The implementation of engineering practices was discussed to provide the detailed assessment of climate change impacts, risks, and adaptation for sustainable development. The narrative methods of reviewing the literatures were used to get an understanding on the engineering practices of water infrastructures, implication of the government policies, and several models as the main motivation behind the concept of integrated water resource management to contribute as part of the sustainable development goals to achieve a better and more sustainable future for all. The findings of this review highlighted the impacts of climate change on the rivers, sea, lakes, dams, and groundwater affecting the availability of water for domestic and industrial water supplies, irrigation, hydropower, and fisheries. The impacts of climate change on the water-related disasters have been indicated affecting drought-flood abrupt alternation and water pollution. Challenges of water management practices facing climate change should be aware of the updated intensity-duration-frequency curves, alternative sources of water, effective water demand management, efficiency of irrigation water, inter-basin water transfer, and nonrevenue water. The transferability of this review findings contribute to an engagement with the society and policy makers to mobilize for climate change adaptation in the water sector.

Matched MeSH terms: Climate Change
Defaunation impacts on the carbon balance of tropical forests

Brodie JF, Bello C, Emer C, Galetti M, Luskin MS, Osuri A, et al.

Conserv Biol, 2025 Feb;39(1):e14414.
PMID: 39466005 DOI: 10.1111/cobi.14414

The urgent need to mitigate and adapt to climate change necessitates a comprehensive understanding of carbon cycling dynamics. Traditionally, global carbon cycle models have focused on vegetation, but recent research suggests that animals can play a significant role in carbon dynamics under some circumstances, potentially enhancing the effectiveness of nature-based solutions to mitigate climate change. However, links between animals, plants, and carbon remain unclear. We explored the complex interactions between defaunation and ecosystem carbon in Earth's most biodiverse and carbon-rich biome, tropical rainforests. Defaunation can change patterns of seed dispersal, granivory, and herbivory in ways that alter tree species composition and, therefore, forest carbon above- and belowground. Most studies we reviewed show that defaunation reduces carbon storage 0-26% in the Neo- and Afrotropics, primarily via population declines in large-seeded, animal-dispersed trees. However, Asian forests are not predicted to experience changes because their high-carbon trees are wind dispersed. Extrapolating these local effects to entire ecosystems implies losses of ∼1.6 Pg CO2 equivalent across the Brazilian Atlantic Forest and 4-9.2 Pg across the Amazon over 100 years and of ∼14.7-26.3 Pg across the Congo basin over 250 years. In addition to being hard to quantify with precision, the effects of defaunation on ecosystem carbon are highly context dependent; outcomes varied based on the balance between antagonist and mutualist species interactions, abiotic conditions, human pressure, and numerous other factors. A combination of experiments, large-scale comparative studies, and mechanistic models could help disentangle the effects of defaunation from other anthropogenic forces in the face of the incredible complexity of tropical forest systems. Overall, our synthesis emphasizes the importance of-and inconsistent results when-integrating animal dynamics into carbon cycle models, which is crucial for developing climate change mitigation strategies and effective policies.

Matched MeSH terms: Tropical Climate*; Climate Change*
Fulltext Urban governance and the systems approaches to health-environment co-benefits in cities

Oliveira JA, Doll CN, Siri J, Dreyfus M, Farzaneh H, Capon A

Cad Saude Publica, 2015 Nov;31 Suppl 1:25-38.
PMID: 26648361 DOI: 10.1590/0102-311X00010015

The term "co-benefits" refers to positive outcomes accruing from a policy beyond the intended outcome, often or usually in other sectors. In the urban context, policies implemented in particular sectors (such as transport, energy or waste) often generate multiple co-benefits in other areas. Such benefits may be related to the reduction of local or global environmental impacts and also extend into the area of public health. A key to identifying and realising co-benefits is the adoption of systems approaches to understand inter-sectoral linkages and, in particular, the translation of this understanding to improved sector-specific and city governance. This paper reviews a range of policies which can yield health and climate co-benefits across different urban sectors and illustrates, through a series of cases, how taking a systems approach can lead to innovations in urban governance which aid the development of healthy and sustainable cities.

Matched MeSH terms: Climate Change*
Demographic properties shape tree size distribution in a Malaysian rain forest

Kohyama TS, Potts MD, Kohyama TI, Kassim AR, Ashton PS

Am Nat, 2015 Mar;185(3):367-79.
PMID: 25674691 DOI: 10.1086/679664

Different mechanisms have been proposed to explain how vertical and horizontal heterogeneity in light conditions enhances tree species coexistence in forest ecosystems. The foliage partitioning theory proposes that differentiation in vertical foliage distribution, caused by an interspecific variation in mortality-to-growth ratio, promotes stable coexistence. In contrast, successional niche theory posits that horizontal light heterogeneity, caused by gap dynamics, enhances species coexistence through an interspecific trade-off between growth rate and survival. To distinguish between these theories of species coexistence, we analyzed tree inventory data for 370 species from the 50-ha plot in Pasoh Forest Reserve, Malaysia. We used community-wide Bayesian models to quantify size-dependent growth rate and mortality of every species. We compared the observed size distributions and the projected distributions from size-dependent demographic rates. We found that the observed size distributions were not simply correlated with the rate of population increase but were related to demographic properties such as size growth rate and mortality. Species with low relative abundance of juveniles in size distribution showed high growth rate and low mortality at small tree sizes and low per-capita recruitment rate. Overall, our findings were in accordance with those predicted by foliage partitioning theory.

Matched MeSH terms: Tropical Climate*
Fulltext A preliminary appraisal of the effect of pumping on seawater intrusion and upconing in a small tropical island using 2D resistivity technique

Kura NU, Ramli MF, Ibrahim S, Sulaiman WN, Zaudi MA, Aris AZ

ScientificWorldJournal, 2014;2014:796425.
PMID: 25574493 DOI: 10.1155/2014/796425

The existing knowledge regarding seawater intrusion and particularly upconing, in which both problems are linked to pumping, entirely relies on theoretical assumptions. Therefore, in this paper, an attempt is made to capture the effects of pumping on seawater intrusion and upconing using 2D resistivity measurement. For this work, two positions, one perpendicular and the other parallel to the sea, were chosen as profile line for resistivity measurement in the coastal area near the pumping wells of Kapas Island, Malaysia. Subsequently, water was pumped out of two pumping wells simultaneously for about five straight hours. Then, immediately after the pumping stopped, resistivity measurements were taken along the two stationed profile lines. This was followed by additional measurements after four and eight hours. The results showed an upconing with low resistivity of about 1-10 Ωm just beneath the pumping well along the first profile line that was taken just after the pumping stopped. The resistivity image also shows an intrusion of saline water (water enriched with diluted salt) from the sea coming towards the pumping well with resistivity values ranging between 10 and 25 Ωm. The subsequent measurements show the recovery of freshwater in the aquifer and how the saline water is gradually diluted or pushed out of the aquifer. Similarly the line parallel to the sea (L2) reveals almost the same result as the first line. However, in the second and third measurements, there were some significant variations which were contrary to the expectation that the freshwater may completely flush out the saline water from the aquifer. These two time series lines show that as the areas with the lowest resistivity (1 Ωm) shrink with time, the low resistivity (10 Ωm) tends to take over almost the entire area implying that the freshwater-saltwater equilibrium zone has already been altered. These results have clearly enhanced our current understanding and add more scientific weight to the theoretical assumptions on the effects of pumping on seawater intrusion and upconing.

Matched MeSH terms: Tropical Climate*

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