Zooplankton community of Bakreswar reservoir: Assessment and visualization of distribution pattern using self-organizing maps

Self-organizing maps, otherwise known as Kohonen-maps, are one form of unsupervised artificial neural networks that can produce two-dimensional plots from multidimensional data. This tool is especially useful in community pattern analyses and has been previously used in spatial pattern analysis with different perspectives. The present study aims to find zooplankton's community pattern in the Bakreswar reservoir ecosystem. Bakreswar reservoir is a freshwater ecosystem in the Birbhum district of West Bengal, India. The reservoir is primarily used to supply freshwater to the Bakreswar thermal power plant. However, the local villages around the reservoir depend on it for drinking water and fishing sustenance. The data used in this study was collected over two years from three different stations. Thus, in addition to describing the spatial pattern of community distribution of zooplankton groups, the temporal variation was also studied. It is observed in the study that the four major groups of zooplankton – Copepoda, Cladocera, Ostracoda, and Rotifera – react differently to the different environmental attributes. Primarily directed by the physical environmental factors, the effect of the chemical factors on the patterning is also evident from the study. Copepods are the dominant group in the system, closely followed by cladocerans and rotifers. But this observation changes at different stations and throughout the study period. The temperature profiles of the reservoir primarily direct the occurrence of ostracods and rotifers, whereas cladocerans and copepods are inclined more towards a chemical factor directive. Rotifers are dominant in the monsoon, whereas the post-monsoon and winter seasons show an increased presence of copepods and cladocerans. The overall observation that the reservoir's water quality is good, and the trophic structure is healthy is in accordance with previous studies as well.     

Modeling ecosystem impacts of the invasive Japanese smelt Hypomesus nipponensis in Lake Erhai,southwestern China

Introductions or alien species invasions will induce changes in aquatic ecosystems but are rarely reported in Chinese highland lakes. The Japanese smelt (Hypomesus nipponensis) invaded and has become a dominant fish species in Lake Erhai, a highland lake in southwestern China, since 2016. Here, we engineered Ecopath models for two different periods, 2008–2009 (preinvasion) and 2016–2018 (postinvasion), in Lake Erhai to model ecosystem impacts from the Japanese smelt invasion. In the dynamic Ecosim model based on the 2016–2018 Ecopath model, we ran three 50-year scenarios to simulate the potential effects of Japanese smelts on the system. Our results showed competition between invasive and native species as well as changes in trophic structures, highlighting the impacts of the invasive species over time. The lake ecosystem additionally experienced significant degradation after invasion, mainly reflected in several related indicators, such as total biomass/total system throughput (TB/TST), total primary production/total biomass (TPP/TB), total primary production/total respiration (TPP/TR), Finn's mean path length (FML), Finn's cycling index (FCI) and the Connectance Index (CI). The simulation results indicated that the relative biomass of icefish (Neosalanx taihuensis), bighead carp (Hypophthalmichthys nobilis), sharpbelly (Hemiculter leucisculus), and zooplankton were significantly affected by increasing the strength of the top-down control of the Japanese smelt on its prey. It is also important to do ecological regulation of planktivorous fishes in the studied Lake Erhai, especially the Japanese smelt.     

Invasive bivalves increase benthic communities complexity in neotropical reservoirs

Invasive bivalves often act as ecosystem engineers, generally causing physical alterations in the ecosystems in which they establish themselves. However, the effects of these physical alterations over benthic macroinvertebrate communities’ structure are less clear. The objective of this study was to characterize the ecological effects of the invasive bivalves Corbicula fluminea and Limnoperna fortunei on the structure of benthic macroinvertebrate communities in neo-tropical reservoirs. Three hypotheses were tested: (1) invasive bivalves act as facilitator species to other benthic macroinvertebrates, resulting in communities with higher number of species, abundance and diversity; (2) invasive bivalves change the taxonomic composition of benthic macroinvertebrate communities; (3) invasive bivalves increase the complexity of benthic macroinvertebrate communities. For that it was used data from 160 sampling sites from four reservoirs. We sampled sites once in each area, during the dry season from 2009 to 2012. The first hypothesis was rejected, as the presence of invasive bivalves significantly decreased the host benthic communities’ number of species and abundance. The second hypothesis was corroborated, as the composition of other benthic macroinvertebrates was shown to be significantly different between sites with and without invasive bivalves. We observed a shift from communities dominated by common soft substrate taxa, such as Chironomidae and Oligochaeta, to communities dominated by the invasive Gastropoda Melanoides tuberculata. The biomass data corroborated that, showing significantly higher biomass of M. tuberculata in sites with invasive bivalves, but significantly lower biomass of native species. Benthic macroinvertebrate communities presenting invasive bivalves showed significantly higher eco-exergy and specific eco-exergy, which corroborate the third hypothesis. These results suggest that while the presence of invasive bivalves limits the abundance of soft bottom taxa such as Chironomidae and Oligochaeta, it enhances benthic communities’ complexity and provide new energetic pathways to benthic communities in reservoirs. This study also suggests a scenario of invasion meltdown, as M. tuberculata was facilitated by the invasive bivalves.     

Emergy and eco-exergy evaluation of four forest restoration modes in southeast China

Four different forest restoration modes (Acacia mangium plantation, mixed-native species plantation, conifer plantation and Eucalyptus plantation) were evaluated using Energy System Theory and the emergy synthesis method. In addition, the eco-exergies of the four forest restoration modes were calculated, and combined with emergy and empower density to explore the restoration and self-organization efficiencies of these modes. The results showed that the two plantations of exotic species, especially the Acacia mangium plantation, were best for biomass accumulation and soil improvement, whereas the two plantations of native species, especially the mixed-native plantation, were more efficient in capturing the available natural resources. Transformity is an important emergy index for the evaluation of system efficiency, because it takes both input and output into account. In subtropical plantations, trees mainly contribute to eco-exergy, whereas herbs and shrubs mainly contribute to specific eco-exergy. The c-value Paradox does exist in conifer species in this study, and it could affect the eco-exergy evaluation. The joint use of eco-exergy and emergy analysis is helpful in comparing both different and similar kinds of ecosystems.     

Impact assessment of an invasive macrophyte community on ecosystem properties: A Mass Balance Approach for Chilika lagoon,India

Phragmites karka (commonly known as Nala grass) is considered an invasive macrophyte, covering an area of 105.1 sq. km, hindering navigation and impacting the ecosystem functioning of Chilika Lagoon (1165 sq.km). The mass balanced models of three different scenarios of Chilika Lagoon were developed using Ecopath to assess the impact of the invasive macrophyte P. karka on the various ecological attributes of the ecosystem. The three different scenarios modelled were (1) a real-time scenario with 23 functional groups that includes P. karka as a group, (2) a virtual scenario with only 22 functional groups where the system is devoid of P. karka, and (3) a virtual scenario that has 22 groups but is devoid of the functional group seagrass and other macrophytes. The results of our study indicate that scenario-2, which is devoid of the macrophyte P. karka, was found to be a relatively mature and resilient ecosystem with the highest utilisation of primary production within the system. This scenario also possesses the highest overhead (67.47%) and Finn's cycling index (FCI) (4.226%) in comparison to the other two scenarios. The ecosystem indices showed a negative impact of P. karka on the trophic functioning of the Chilika Lagoon, which warrants an urgent need to remove the macrophyte to improve the resilience of the ecosystem.     

Effects of subsidy quality on reciprocal subsidies: how leaf litter species changes frog biomass export

Spatial subsidies are resources transferred from one ecosystem to another and which can greatly affect recipient systems. Increased subsidy quantity is known to increase these effects, but subsidy quality is likely also important. We examined the effects of leaf litter quality (varying in nutrient and tannin content) in pond mesocosms on gray treefrog (Hyla versicolor) biomass export, as well as water quality and ecosystem processes. We used litter from three different tree species native to Missouri [white oak (Quercus alba), northern red oak (Quercus rubra), and sugar maple (Acer saccharum)], one non-native tree [white pine (Pinus strobus)], and a common aquatic grass [prairie cordgrass (Spartina pectinata)]. We found that leaf litter species affected almost every variable we measured. Gray treefrog biomass export was greatest in mesocosms with grass litter and lowest with white oak litter. Differences in biomass export were affected by high tannin concentrations (or possibly the correlated variable, dissolved oxygen) via their effects on survival, and by primary production, which altered mean body mass. Effects of litter species could often be traced back to the characteristics of the litter itself: leaf nitrogen, phosphorus, and tannin content, which highlights the importance of plant functional traits in affecting aquatic ecosystems. This work and others stress that changes in forest species composition could greatly influence aquatic systems and aquatic–terrestrial linkages.     

Effects of eutrophication and exotic crayfish on health status of two Spanish lakes: a joint application of ecological indicators

Lake Sentiz and Lake Chozas are two small water bodies in the Province of León (NW Spain). The former is mesotrophic and the latter went from oligotrophic to turbid in 1997, due to introduction of an invasive allochthonous crayfish Procambarus clarkii (Rodríguez et al., 2003, Rodríguez et al., 2005, Marchi et al., 2011a, Marchi et al., 2011b). We set out to study health status of the two ecosystems by the joint use of different but correlated ecological indicators, supplementing the values obtained by monitoring campaigns. We examine three scenarios: (1) Lake Sentiz, (2) Lake Chozas before and (3) Lake Chozas after the biological invasion. We evaluate eco-exergy, emergy and eco-exergy–empower ratio, three holistic ecological indicators based on the thermodynamics of far-from-equilibrium systems. When structural changes take place in ecosystems it is recommended to apply holistic thermodynamic indicators as presented in Jørgensen et al., 2010a, Jørgensen et al., 2010b. We propose their joint application for a complete overview of the monetary value of natural capital, because they provide information added to statistical analysis and direct measurement. The aim is to determine which of these indicators best represents the effects of eutrophication and perturbations caused by alien species in the two freshwater systems. The eco-exergy–empower ratio gives the best results, since it clearly indicates lake efficiency in transforming direct and indirect solar energy inputs into organization. The eco-exergy (work capacity) results are used to estimate ecosystem services and quantify the economic value of lake natural capital. Calculation of ecosystem services on an eco-exergy basis provides good indications of monetary gains or losses possible in perturbed systems, including eutrophic or invaded ecosystems. This is not surprising, because work capacities include all possible services offered by ecosystems, not only the services actually used by humans. Eco-exergy and the eco-exergy–empower ratio can be guidelines for the calculation of ecosystem services, although they give only a partial indication of the environmental costs and benefits of a given level of information. The present results suggest political and economic considerations and solutions, and are a useful example for organisations involved in environmental management of pollution and biological invasions by exotic species.     

Influence of vegetation structure on the small mammal community in a shortgrass prairie ecosystem

The structure of vegetation, and how this structure varies across a landscape, is crucial to understanding the distribution of wildlife species. Between 2002 and 2004, we sampled small mammal communities and measured vegetation structure at 185 locations across a range of disturbance regimes in a shortgrass prairie ecosystem in southeastern Colorado, USA. At each sampling location, the local disturbance regime was some combination of varying intensity of livestock grazing, military training activity, and fire. Vegetation structural characteristics measured included percent bare ground, basal cover, litter, shrub density, and mean grass and shrub height. Rodent communities were described by richness, diversity, total and per capita biomass, and species abundances. Northern grasshopper mice (Onychomys leucogaster), Ord's kangaroo rats (Dipodomys ordii), silky pocket mice (Perognathus flavus), western harvest mice (Reithrodontomys megalotis), white-footed mice (Peromyscus leucopus), southern plains wood rats (Neotoma micropus), thirteen-lined ground squirrels (Spermophilus tridecemlineatus), deer mice (Peromyscus maniculatus), and spotted ground squirrels (Spermophilus spilosoma) accounted for >99 % of all captures. Canonical correlation analysis was used to assess the relationship between small mammals and vegetation structure. The first two canonical variates explained over 50 % of the variation in vegetation structure and were related to the ratio of bare ground to basal coverage and litter accumulation. Rodent community indices were most strongly related to litter accumulation and shrub density, though the models had low explanatory power. Our results agreed with published findings regarding microhabitat associations and indicated small mammal communities benefited from a system of interacting disturbances and the resulting landscape mosaic.     

Response of Daphnia's Antioxidant System to Spatial Heterogeneity in Cyanobacteria Concentrations in a Lowland Reservoir

Many species and clones of Daphnia inhabit ecosystems with permanent algal blooms, and they can develop tolerance to cyanobacterial toxins. In the current study, we examined the spatial differences in the response of Daphnia longispina to the toxic Microcystis aeruginosa in a lowland eutrophic dam reservoir between June (before blooms) and September (during blooms). The reservoir showed a distinct spatial pattern in cyanobacteria abundance resulting from the wind direction: the station closest to the dam was characterised by persistently high Microcystis biomass, whereas the upstream stations had a significantly lower biomass of Microcystis. Microcystin concentrations were closely correlated with the cyanobacteria abundance (r = 0.93). The density of daphniids did not differ among the stations. The main objective of this study was to investigate how the distribution of toxic Microcystis blooms affects the antioxidant system of Daphnia. We examined catalase (CAT) activity, the level of the low molecular weight antioxidant glutathione (GSH), glutathione S-transferase (GST) activity and oxidative stress parameters, such as lipid peroxidation (LPO). We found that the higher the abundance (and toxicity) of the cyanobacteria, the lower the values of the antioxidant parameters. The CAT activity and LPO level were always significantly lower at the station with the highest M. aeruginosa biomass, which indicated the low oxidative stress of D. longispina at the site with the potentially high toxic thread. However, the low concentration of GSH and the highest activity of GST indicated the occurrence of detoxification processes at this site. These results demonstrate that daphniids that have coexisted with a high biomass of toxic cyanobacteria have effective mechanisms that protect them against the toxic effects of microcystins. We also conclude that Daphnia''s resistance capacity to Microcystis toxins may differ within an ecosystem, depending on the bloom''s spatial distribution.     

Application of specific exergy to macrophytes as an integrated index of environmental quality for coastal lagoons

This work aims to explore the application of specific exergy on macrophytes as an integrated index to assess ecosystem health in coastal lagoons, and to analyse its possible application in view of the implementation of the Water Framework Directive of the European Union (European Commission, 2000). Exergy and specific exergy are calculated as a function of the biomass multiplied by a weighting factor (β), which express the quantity of information embedded in the biomass. Until now only few general values of β have been published. Therefore, we have extended the calculation of β-values for 244 seaweed and seagrass species which are common in Mediterranean coastal lagoons. The estimated β-values have been then compared with macrophyte-based indicators which have been recently developed, namely the Ecological Evaluation Index and the IFREMER classification scheme. Overall, we found a good agreement between β-values and macrophyte indicators. Furthermore, the specific exergy was calculated for 71 sites in coastal lagoons of Southern France and compared with existing classification schemes, finding a good agreement between them. As a result, we argue that specific exergy may be used as an integrated index that is able to synthesize and complement existing approaches.     

Predicting Ecosystem Wide Impacts of Wallaby Management Using a Fuzzy Cognitive Map

At Booderee National Park, south-eastern Australia, the intensive control of the introduced red fox (Vulpes vulpes) resulted in a major increase in the abundance of a browsing macropod, the swamp wallaby (Wallabia bicolor). This has led to a major decrease in the abundance and biomass of a range of palatable plant species. Fox control has also started a trophic cascade that has resulted in a decline in the abundance of the greater glider (Petauroides volans) a folivorous arboreal marsupial, mediated either through increased predation by owls or increased competition with common brushtail possums (Trichosurus vulpecula). We identified five potential scenarios for managing the effects of over-abundant swamp wallabies on the ecosystem as a whole. These were (1) the present scenario of continued intensive fox control and four possible scenarios to redress the problem: (2) ceasing fox control; (3) intensive fox control and intensive wallaby control; (4) introducing dingoes and ceasing fox control; and (5) introducing dingoes and maintaining fox control. We used an ecosystem modelling approach based on a fuzzy cognitive map (FCM) to predict relative estimates of abundance for each scenario for a wide range of taxa in the Booderee National Park ecosystem likely to be affected by each scenario. We addressed uncertainty in our knowledge of the interactions between species by creating alternative models of the system by removing one or more of the uncertain links between species and varying the strength of the remaining interactions in the FCM and aggregated predictions from 100,000 models to estimate the effect of uncertainty on the predictions from our FCM model. In comparison with the current scenario of intensive fox control, scenario 3 had the greatest likelihood of improving the status of palatable plants. Scenarios 2 and 4 reduced the abundance of a range of medium-sized mammals but improved the status of greater gliders, whereas the predicted effects of scenario 5 were uncertain. The FCM modelling approach developed here provided a valuable tool for managers to learn about the potential ecosystem wide effects of management actions while incorporating the likely effects of uncertain knowledge on system outcomes.     

Ecosystem services,sustainability and thermodynamic indicators

It is proposed to calculate the value of ecosystem services by the annual increase of work capacity or eco-exergy. The annual increase of biomass for various ecosystems is known. By multiplication of the biomass increase by the average content of information as Kullbach's measure of information, in the various ecosystems, the eco-exergy or total work capacity is obtained. An economic value can be found by multiplication of the cost of work, which is about 1 EURO-cent per MJ. A comparison of this value with the values found by Costanza et al. (1997) shows that the value based upon the total work capacity is much higher. The ratio between the two economic values have been found for the various ecosystems. It has been found that the ratio is lower the more an ecosystem by a wide range of application possibilities is utilized. The ecosystems have been divided in five classes according to the ratio and thereby in accordance to our utilization of the total work capacity of various ecosystems.     

青海省高寒灌丛物种多样性、生物量及其关系

物种多样性对生态系统功能的作用是生物多样性研究的核心领域之一,生物量水平是生态系统功能的重要表现形式,而植物群落的生物量则是生态系统生物量的基础,因此研究植物群落物种多样性与生物量的关系,对于阐明植物多样性对生态系统功能的作用具有重要意义。通过对青海省高寒灌丛生物量、灌丛物种多样性特征以及与生物量的关系调查,得到以下结果:(1)被调查灌木植被群落的40个样地中共出现了207种植物(其中灌木植物18种,草本植物189种),隶属于130属,43科,灌木以蔷薇科、杜鹃花科为主,而草本以菊科、龙胆科、毛茛科和莎草科占优势。(2)群落多样性指数偏低,植物群落结构简单,物种组成稀少。小叶金露梅群落的多样性指数最大,金露梅群落、细枝绣线菊群落和鲜卑花群落次之,百里香杜鹃+头花杜鹃群落最低。(3)不同高寒灌丛类型生物量介于1893.03—7585.41 g/m~2之间,平均值为3775.9 g/m2,其中灌木生物量占灌丛总生物量的73.55%,草本为26.45%。(4)总生物量随草本物种多样性和群落物种多样性的增加而减小;草本生物量随其物种多样性的增加而减小,而灌木物种多样性与其生物量并无显著相关性。     

Preliminary investigation on the changes in trophic structure and energy flow in the Yangtze estuary and adjacent coastal ecosystem due to the Three Gorges Reservoir

Water projects in the Yangtze River basin, especially the Three Gorges Reservoir (TGR), have strongly affected the biological and ecological integrity of the Yangtze estuary and adjacent coastal ecosystems. The Ecopath with Ecosim model was applied to study trophic structure and energy flow after the impoundment of TGR based on field surveys in 2006. The model results showed that the trophic levels ranged from 1.000 to 4.058; and 44% of the energy flows originated from the detritus food chain, while 56% originated from the grazing food chain in the trophic transfer process; the transfer efficiency of the ecosystem was 10.0%, and TPP/TR (Total Primary Production/Total Respiration) was 1.899. Compared with model results in 2000 (before impoundment of TGR), the trophic structure of the ecosystem did not exhibit substantial changes; however, the mean trophic level and catch amount decreased remarkably after impoundment. The estuary and adjacent coastal ecosystems were found to be more sensitive to external perturbations after impoundment.     

Estimation of ecological exergy using weighing parameters determined from DNA contents of organisms – a case study

We studied the changes of exergy and specific exergy with data of benthic macrofauna communities, periodically sampled along an estuarine gradient of eutrophication in the Mondego estuary (Western Portugal). Exergy estimates were calculated from organism biomass, based on weighing factors for the relative content of exergy per unit of biomass determined from DNA contents of organisms. Results were discussed in terms of both the macrofauna biomass production and the structural organisation of the system. Estimates for the exergy indices provided useful indications for the evaluation of environmental impact due to the eutrophication process. Different average values for the indices of exergy and specific exergy were estimated relatively to areas with different levels of eutrophication, in the spatial gradient of eutrophication. Higher exergy levels and lower exergy content per unit of biomass (specific exergy) were associated to populations more stabilized or areas less perturbed. Additionally, the index of specific exergy seemed capable of providing indications for the qualitative alterations in the communities (in temporal and spatial terms) that go in the direction of the observations made in this ecosystem.     

Ecosystem Engineering by Plants on Wave-Exposed Intertidal Flats Is Governed by Relationships between Effect and Response Traits

In hydrodynamically stressful environments, some species—known as ecosystem engineers—are able to modify the environment for their own benefit. Little is known however, about the interaction between functional plant traits and ecosystem engineering. We studied the responses of Scirpus tabernaemontani and Scirpus maritimus to wave impact in full-scale flume experiments. Stem density and biomass were used to predict the ecosystem engineering effect of wave attenuation. Also the drag force on plants, their bending angle after wave impact and the stem biomechanical properties were quantified as both responses of stress experienced and effects on ecosystem engineering. We analyzed lignin, cellulose, and silica contents as traits likely effecting stress resistance (avoidance, tolerance). Stem density and biomass were strong predictors for wave attenuation, S. maritimus showing a higher effect than S. tabernaemontani. The drag force and drag force per wet frontal area both differed significantly between the species at shallow water depths (20 cm). At greater depths (35 cm), drag forces and bending angles were significantly higher for S. maritimus than for S. tabernaemontani. However, they do not differ in drag force per wet frontal area due to the larger plant surface of S. maritimus. Stem resistance to breaking and stem flexibility were significantly higher in S. tabernaemontani, having a higher cellulose concentration and a larger cross-section in its basal stem parts. S. maritimus had clearly more lignin and silica contents in the basal stem parts than S. tabernaemontani. We concluded that the effect of biomass seems more relevant for the engineering effect of emergent macrophytes with leaves than species morphology: S. tabernaemontani has avoiding traits with minor effects on wave attenuation; S. maritimus has tolerating traits with larger effects. This implies that ecosystem engineering effects are directly linked with traits affecting species stress resistance and responding to stress experienced.     

Gemfibrozil and Fenofibrate,Food and Drug Administration-approved Lipid-lowering Drugs,Up-regulate Tripeptidyl-peptidase 1 in Brain Cells via Peroxisome Proliferator-activated Receptor α: IMPLICATIONS FOR LATE INFANTILE BATTEN DISEASE THERAPY*

The classical late infantile neuronal ceroid lipofuscinosis (LINCLs) is an autosomal recessive disease, where the defective gene is Cln2, encoding tripeptidyl-peptidase I (TPP1). At the molecular level, LINCL is caused by accumulation of autofluorescent storage materials in neurons and other cell types. Currently, there is no established treatment for this fatal disease. This study reveals a novel use of gemfibrozil and fenofibrate, Food and Drug Administration-approved lipid-lowering drugs, in up-regulating TPP1 in brain cells. Both gemfibrozil and fenofibrate up-regulated mRNA, protein, and enzymatic activity of TPP1 in primary mouse neurons and astrocytes as well as human astrocytes and neuronal cells. Because gemfibrozil and fenofibrate are known to activate peroxisome proliferator-activated receptor-α (PPARα), the role of PPARα in gemfibrozil- and fenofibrate-mediated up-regulation of TPP1 was investigated revealing that both drugs up-regulated TPP1 mRNA, protein, and enzymatic activity both in vitro and in vivo in wild type (WT) and PPARβ^−/−, but not PPARα^−/−, mice. In an attempt to delineate the mechanism of TPP1 up-regulation, it was found that the effects of the fibrate drugs were abrogated in the absence of retinoid X receptor-α (RXRα), a molecule known to form a heterodimer with PPARα. Accordingly, all-trans-retinoic acid, alone or together with gemfibrozil, up-regulated TPP1. Co-immunoprecipitation and ChIP studies revealed the formation of a PPARα/RXRα heterodimer and binding of the heterodimer to an RXR-binding site on the Cln2 promoter. Together, this study demonstrates a unique mechanism for the up-regulation of TPP1 by fibrate drugs via PPARα/RXRα pathway.     

Quantifying tree carbon stock in historically conserved Seminary Hills urban forest of Nagpur,India

Urban forests help regulating flow of ecosystem services and are efficient to sequester atmospheric carbon. Tree carbon stock in urban forests and green spaces can help improving human well-being. Nagpur being one of the fastest growing urban agglomerate in India that has faced rapid loss of green spaces in last three decades. Present study assessed tree biomass carbon storage potential of a historically conserved large (67.41 ha) Seminary Hills Reserve forest of Nagpur. A total of 150 quadrats of 100 m² were laid to understand the vegetation structure and tree biomass storage. Overall structure and composition of the forest was assessed while, non-destructive biomass estimation was carried out using tree volume eqs. A total of 27 tree species belonging to 12 plant families were observed from the forest with only 6 tree species being dominant and remaining 21 being rare in occurrence. The maximum tree carbon storage was observed in dominant tree species of Hardwickia binata (76.30 t C ha^?1) followed by 17.04 t C ha^?1 in Tectona grandis and 1.19 t C ha^?1 in Boswellia serrata. Carbon stock in other co-dominant species was reported in Terminalia bellirica (76.57 kg C ha^?1), Gardenia resinifera (1118.6 g C ha^?1) and Terminalia arjuna (84.8 g C ha^?1). Total carbon stock of dominant tree species present in Seminary Hills urban forest was 94.53 ± 39.6 t C ha^?1. The study intends to bring focus ecosystem benefits from Urban Forests in growing urban sprawls of India and the need to include their vital role in urban planning.     

Xylem cavitation affects the recovery of plant water status and consequently acorn production in a holm oak open woodland

The hydraulic conductivity and gas exchange parameters of holm oak trees (Quercus ilex ssp. ballota (Desf.) Samp.) from an open woodland ecosystem in southwestern Spain were determined in young shoots (≤1 year old) over the course of 3 years, at 6–7 week intervals. Acorn production (AP) was also determined. Specific hydraulic conductivity (K _s), leaf specific hydraulic conductivity (K _l), loss of hydraulic conductivity (PLC), and xylem water potential (Ψ) were assessed. In addition, histological cuttings of stem cross sections were examined to determine the density and diameter of xylem vessels. Acorn production was related to mid-summer K _s and PLC values, but not for other dates or to parameters associated with instantaneous gas exchange. Although AP may depend on several physiological and climatic variables, these results indicated a close non-linear relation between hydraulic conductivity during periods of summer water stress and AP. It was difficult to recover xylem conductivity after a rain event when the PLC of twigs exceeded a threshold of approximately 68 %, which therefore had a negative effect on the AP. However, if the PLC ≤ 55 %, then the hydraulic conductivity and Ψ could be quickly recovered after a rain event and the effect of water stress would have less importance. Because holm oak usually operates at the limits of safety for hydraulic conductivity, which are surpassed under severe water stress (Ψ _predawn ≤ ?3.0 MPa), a global change scenario leading to drier conditions in the Mediterranean basin will increase the negative effects of summer drought on AP, leading to negative consequences for the ecosystem dynamics. The right choice of drought-adapted ecotypes and silvicultural practices that increase soil water retention and reduce plant competition should be taken into account for forest management.