The predicted effects of climate change on local species distributions around Beijing,China

To assist conservationists and policymakers in managing and protecting forests in Beijing from the effects of climate change,this study predicts changes for 2012–2112 in habitable areas of three tree species—Betula platyphylla,Quercus palustris,Platycladus orientalis,plus other mixed broadleaf species—in Beijing using a classification and regression tree niche model under the International Panel on Climate Change’s A2 and B2 emissions scenarios(SRES).The results show that climate change will increase annual average temperatures in the Beijing area by 2.0–4.7℃,and annual precipitation by 4.7–8.5 mm,depending on the emissions scenario used.These changes result in shifts in the range of each of the species.New suitable areas for distributions of B.platyphylla and Q.palustris will decrease in the future.The model points to significant shifts in the distributions of these species,withdrawing from their current ranges and pushing southward towards central Beijing.Most of the ranges decline during the initial 2012–2040 period before shifting southward and ending up larger overall at the end of the 88-year period.The mixed broadleaf forests expand their ranges significantly.The P.orientalis forests,on the other hand,expand their range marginally.The results indicate that climate change and its effects will accelerate significantly in Beijing over the next 88 years.Water stress is likely to be a major limiting factor on the distribution of forests and the most important factor affecting migration of species into and out of existing nature reserves.There is a potential for the extinction of some species.Therefore,long-term vegetation monitoring and warning systems will be needed to protect local species from habitat loss and genetic swamping of native species by hybrids.

Vegetation and Community Changes of Elm (Ulmus pumila) Woodlands in Northeastern China in 1983-2011

Elm （Ulmus pumila）, widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental signifi- cance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors af- fected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth （small, short and twisted）. The mean age of the elm was 29 -4- 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups： Group I including the undisturbed sample stands of 83UE （undisturbed elm wood- land in 1983） and l lUE （undisturbed elm woodland in 2011）; Group II including sample stands of PE （elm woodland disturbed by plowing）; Group III including samples stands of GE （elm woodland disturbed by grazing）. The results indicate that the long time distur- bance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.

Elevation patterns of woody taxa richness in the evergreen Afromontane vegetation of Ethiopia

Plant species distributions show patterns along elevation gradients. Regardless of the diverse Afromontane vegetation in Ethiopia (AFE), studies of elevation patterns of woody plants are limited and they are restricted to small areas or single/few Mountains. Moreover, there is no general consensus on the patterns of woody taxa distribution by elevation. The objectives of this study were to examine the elevation patterns of woody taxa richness and their relationship with elevation in the AFE. Data were collected and compiled from the Flora of Ethiopia and Eritrea (Vols. 1-7). About 5918 plant species of 243 families were examined and their elevational distributions were recorded. The distributional ranges of woody taxa were aggregated at 19 points (sites) at 100 m intervals starting from 1500 to 3400 m a.s.l. Single-factor analysis of variance (one-way ANOVA) was used to test the hypothesis that mean species richness of woody taxa decreases from the lower to the upper limit of AFE. Simple linear correlation and regression were used to show the relationships of woody taxa richness with elevation. We documented the presence of 505 woody taxa (441 species, 31 subspecies and 33 varieties) representing 267 genera and 90 families in the AFE. In terms of habit, 279 taxa are shrubs, 178 are trees and 48 are lianas. The distribution of woody taxa (trees, shrubs and lianas) showed a slight increase at the lower portion and a monotonic decline with increasing elevation. Species richness of trees, shrubs and lianas was negatively and significantly correlated with elevation (r = −0.985, −0.984, −0.981, respectively; all p < 0.001). Our hypothesis was accepted because mean richness significantly decreased from the lower to the upper limit of AFE (p < 0.001). Generally, monotonic patterns of decline in richness were observed for trees, shrubs and lianas. The contribution of shrubs to total richness increased with increasing elevation whereas that of trees and lianas decreased.

Gas-phase and particle-phase PCDD/F congener distributions in the flue gas from an iron ore sintering plant

The activated carbon injection-circulating fluidized bed（ACI-CFB）-bag filter coupling technique was studied in an iron ore sintering plant. For comparison, the removal efficiencies under the conditions without or with ACI technology were both evaluated. It was found that the polychlorinated dibenzo-p-dioxins and dibenzofuran（PCDD/F） removal efficiency for total international toxic equivalence quantity（I-TEQ） concentration was improved from 91.61% to 97.36% when ACI was employed, revealing that ACI was very conducive to further controlling the PCDD/F emissions. Detailed congener distributions of PCDD/Fs in the gas-phase and particle-phase of the Inlet and Outlet samples were determined. Additionally, the PCDD/F distribution for the Fly ash-with ACI sample of was also studied.

Seed Size as Key Factor in Germination and Seedling Development of Copaifera langsdorffii(Fabaceae)

Seed size is a plastic trait of the plants that directly affect seed germination and seedling recruitment. This study aimed to investigate the relationship between seed size, seed germinability and seedling performance of Copaifera langsdorffii by testing four hypotheses: 1) larger seeds have higher germination percentage;2) smaller seeds require less time to germinate and for initial development of the seedlings;3) larger seeds produce more vigorous seedlings and 4) seed size negatively affects seedling root/shoot ratio. In 2011, we selected 30 individuals of C. langsdorffii from which 300 seeds were randomly collected in the plant canopy. All these seeds were weighted and placed in germination tray using vermiculite as substrate. Seed germinability and initial development of seedlings were monitored daily until cotyledons fell. Small seeds have higher germination percentage and germinate faster when compared to large seeds. Nonetheless, seedlings originated from larger seeds have longer development times, resulting in more vigorous seedlings. In addition, seedlings originating from small seeds allocate proportionally greater amount of resources to roots when compared to larger seeds. The fact that small seeds have higher germination percentage and faster germination favors the colonization of transient habitats. However, larger seeds produce more vigorous seedlings, favoring the seedling establishment in more stable habitats. Thus, we argue that high variability in seed size of C. langsdorffii favors its widespread geographic distribution.

Vegetation structure and edaphic factors in veredas reflect different conservation status in these threatened areas

Background:In Cerrado humid areas,veredas are considered as hygrophilous communities,marked by the presence of the Mauritia flexuosa palm tree emerging in the wetter zones.Changes in veredas ecosystems due to drought and changes in the water table,which represent important areas for biodiversity maintenance in the Brazilian cerrado,can lead to the emergence of new landscapes and ecosystems.Assuming that the veredas are changed in species composition due to anthropogenic factors,in this study,we evaluated the flora composition and described the current vegetation profile of two veredas under different disturbances levels that are located in the north of Minas Gerais State,Brazil.Results:Altogether,2,268 individuals of 91 species belonging to 36 families were recorded.Our results demonstrated that the studied veredas were floristically different in terms of the arboreous-shrubby species composition,richness,and diversity.Despite the hygrophilous forest formations and open areas in the two veredas present typical species from these environments(same species with high importance values),the drought in the water table caused an expansion of Cerrado species in the open areas and in the hygrophilous forest.Furthermore,in the hygrophilous forest there was an increase in the abundance of species that occur in less saturated soils.Conclusion:Our results demonstrate that the studied veredas are changing in species composition due to anthropogenic factors which leads to the drought of these formations(water balance effect).These anthropogenic effects cause a modification with the expansion and increase in the abundance of typical species of other areas of Cerrado and resistant to less saturated soils,leading to the veredas collapse.Finally,future studies should investigate other veredas on a broader scale to detect changes in the water table that lead to a consequent change in vegetation structure.In this way,we will have support for the conscientious management and conservation of these areas that represent equilibrium places for the Cerrado biome.

THE PIGMENT-PROTEIN COMPLEXES OF HIGHER PLANTS MIGRATION IN THYLAKOID AND THE REGULATION OF LIGHT ENERGY DISTRIBUTION BETWEEN PHOTOSYSTEMS

Appressed and non-appressed lamella membranes of Castor bean leaf chloroplasts were separated by non-ionic detergent Triton-X 100.Appressed membranes showed a high oxygen-evolving activity and low chl a/b ratio. Examining with SDS-PTGE and liquid nitrogen temperature fluorescence measurement showed that they contained only PSII and light-harvesting pigment-protein complexes (LHCP),and there was no detectable amount of PSI. Freeze-fracture electromicroscopic observation confirmed that this part was really an appressed lamella membrane. Through divalent cation Mg^(++), the thylakoid membranes were induced to unstack and restack.With the addition of Mg^(++), the fluorescence intensity was changed instantly. We realized that there existed two processes:One was a rapid process which was accomplished within 30 s. The other was a slow process of which the time duration was about 60 min. This dual effects of Mg^(++) had not been reported before.We had analyzed the change of F685/F730 and discussed the possible rneehanis ms of light energy distribution between photosystems.

Optimization method to obtain appropriate spacing parameters for crop cultivation

Considering the time-consuming and tedious work of the current methods to control plant layout,which is mostly based on expert experience or field trials,we propose an algorithm to optimize and simulate a planting layout based on a virtual plant model and an optimization algorithm.A functional-structural plant model,which combines the structure and physiological function of plants,is used to construct a planting scene.The planting and row spacing are set as the genetic factors and the chromosomes of the genetic algorithm are encoded with a binary method.The photosynthetic yield of the unit planting area is denoted as the fitness value.By using this method,the intercropping of maize and soybean plants and the sole cropping of rice plants are studied.Experimental results show that the proposed method can obtain a high yield planting plan.

Allocation and sizing of reactive power compensators considering PV power and load demand uncertainty using beetle-antenna grey wolf optimization

Distributed photovoltaic(PV)systems play an important role in supplying many recent microgrids.The absence of reactive power support for these small-scale PV plants increases total microgrid losses and voltage-instability threats.Reactive power compensations(RPCs)should be integrated to enhance both microgrid losses and voltage profiles.RPC planning is a non-linear,complicated problem.In this paper,a combined RPC allocation and sizing algorithm is proposed.The RPC-integrating buses are selected using a new adaptive approach of loss sensitivity analysis.In the sizing process,the uncertainties in PV power and load demand are modelled using proper probability density functions.Three simulation techniques for handling uncertainties are compared to define the accurate and fast accurate method as follows:Monte Carlo simulation(MCS),scenario tree construction and reduction method,and point estimation method(PEM).The load flow equations are solved using the forward-backward sweep method.RPCs are optimally sized using the beetle-antenna-based strategy with grey wolf optimization(BGWO)to overcome the local minima problem that appeared in the other pre-proposed methods.Results have been compared using particle swarm optimization and conventional GWO.The proposed model is verified using the IEEE 33 radial bus system.The expected power loss has been reduced by 22% and 31% using compensation of 26% and 44%,respectively.The results obtained prove that the BGWO optimal power flow and PEM to handle the uncertainty can significantly reduce the computation time with sufficient accuracy.Under the study conditions,PEM reduces the computation time to 4 minutes compared with 4 hours for MCS,with only a 3% error compared with MCS as an uncertainty benchmark method.

Spatio-temporal modelling of the effect of selected environmental and land-use factors on acid grassland vegetation

Acid grasslands are threatened both by agricultural intensification with nutrient addition and increased livestock densities as well as by land abandonment.In order to understand and quantify the effect of selected environmental and land-use factors on the observed variation and changes in the vegetation of acid grasslands,large-scale spatial and temporal pin-point plant cover monitoring data are fitted in a structural equation model.The important sources of measurement and sampling uncertainties have been included using a hierarchical model structure.Furthermore,uncertainties associated with the measurement and sampling are separated from the process uncertainty,which is important when generating ecological predictions that may feed into local conservation management decisions.Generally,increasing atmospheric nitrogen deposition led to more grass-dominated acid grassland habitats at the expense of the cover of forbs.Sandy soils were relatively more acidic,and the effects of soil type on the vegetation include both direct effects of soil type and indirect effects mediated by the effect of soil type on soil pH.Both soil type and soil pH affected the vegetation of acid grasslands.Even though only a relatively small proportion of the temporal variation in cover was explained by the model,it would still be useful to quantify the uncertainties when using the model for generating local ecological predictions and adaptive management plans.