Well-dispersed Species Research Articles

Predicting Impacts of Climate Change on Teak and Sal Forests in Central India Using Maximum Entropy Modeling: an Approach for Future Conservation and Silvicultural Strategies

Abstract Climate change impacts on tropical forests and tree species have been documented as changes in distribution, growing period, phenology, habitat, productivity, species composition, and migration. This study attempts to assess the current and future habitat suitability distribution of two dominant species of Central India, teak (Tectona grandis Linn. f.) and sal (Shorea robusta Gaertn. f.) using a maximum entropy (MaxEnt) model to predict species occurrences by finding the distribution that has the most spread. The future suitable habitat ranges of the species were modeled for two time periods (2050 and 2070) and two representative concentration pathways (RCP 2.6 and 8.5). Representative concentration pathways are scenarios that describe alternative trajectories for carbon dioxide emissions and the resulting atmospheric concentration from 2000 to 2100. We collected and modeled the spatially well-dispersed species occurrence points of teak and sal. The results suggested an increase in suitable habitat range for teak and a decrease for sal for both time periods and RCPs. Furthermore, the jackknife analysis identified temperature and precipitation seasonality as the major variables that influence the distribution of teak. In the case of sal, minimum temperature makes the maximum contribution to distribution changes. The suitable silvicultural strategies for forest management are proposed based on the future distribution of species in relation to the climate variables responsible for the change in their distribution range. These findings and strategies will help forest departments build future management plans for teak and sal forest with a focus on minimizing the impact of climate change. Study Implications: Our study used maximum entropy (MaxEnt) modeling to understand the impact of changing climate on the distribution of teak and sal forests of central India and to propose future silvicultural strategies. The study used MaxEnt model for two time periods and two climate change scenarios at highest resolution. An increase in future suitable habitat for teak and a decrease for sal is predicted by the model. Temperature for teak and precipitation for sal were identified as the major influencing climatic variables. We recommend forest and other related government departments to commission focused research to understand the changing patterns of species with climate change and design appropriate silviculture strategies for effective management.

Tree logs for grassland restoration? Lessons from an unintentional experiment

For subtropical Brazilian grasslands, few restoration techniques are established, and seeds of native grassland species are not available on the market. Here, we evaluated the effect of physical barriers (PB) on vegetation recovery in a degraded grassland. We considered species that exhibit attributes in their diaspores that facilitate dispersal as well‐dispersed species (WDS) and compared the proportion of WDS at our site to their proportion in the regional species pool. To analyze plots near and distant from the PB, we calculated the extrapolated metrics by an asymptotic estimator (double sample size of each distance). We found 74 species in the degraded area, with higher richness and Shannon diversity values closer to logs, but higher Simpson values with larger distance from logs. Almost half of the species in the degraded area are WDS, more than in the regional species pool. While effects of logs on microsite conditions may also play a role (e.g. logs accumulating organic material or increasing soil moisture, providing shade), our data indicates that the PB works as a seed trap favoring the occurrence of WDS. It seems promising to develop applications in restoration, especially when associating PB with other restoration techniques to increase availability of adequate germination and establishment conditions.

Deoxydehydration of Biomass-Derived Polyols Over Silver-Modified Ceria-Supported Rhenium Catalyst with Molecular Hydrogen.

Olefin production from polyols via deoxydehydration (DODH) was carried out over Ag-modified CeO2 -supported heterogeneous Re catalysts with H2 as a reducing agent. Both high DODH activity and low hydrogenation ability for C=C bonds were observed in the reaction of erythritol, giving a 1,3-butadiene yield of up to 90 % under "solvent-free" conditions. This catalyst is applicable to other substrates such as methyl glycosides (methyl α-fucopyranoside: 91 % yield of DODH product; methyl β-ribofuranoside: 88 % yield), which were difficult to be converted to the DODH products over the DODH catalysts reported previously. ReOx -Ag/CeO2 was reused 3 times without a decrease of activity or selectivity after calcination as regeneration. Although the transmission electron microscopy energy-dispersive X-ray spectroscopy and X-ray absorption fine structure analyses showed that Re species were highly dispersed and Ag was present as metal particles with various sizes from well-dispersed species (<1 nm) to around 5 nm particles, the catalysts prepared from size-controlled Ag nanoparticles showed similar performance, indicating that the catalytic performance is insensitive to the Ag particle size.

Modeling the ecological niche and features of coprobiontic fungi distribution in Asia by the example of &lt;i&gt;Cyathus stercoreus&lt;/i&gt;

Species distribution is undergoing rapid changes in the face of habitat modification and climate change. This leads to concerns about the conservation of declining species and raises ecological questions about the processes that govern species ranges and niches. As a consequence, the predictive distribution models which match species records to patterns in abiotic environmental variables have become an established tool in ecology and conservation. Maximum entropy spatial distribution modelling (MaxEnt) solves this problem by inferring species distributions and environmental tolerance based on the occurrence data. The objectives of this research were the ecological niche and running the habitat suitability modelling on dung fungal species Cyathus stercoreus based on its bioclimatic and substrate features within Asia. We constructed a map of the current geographical distribution of the dung fungus Cyathus stercoreus using MaxEnt method. We included in the model 19 WorldClim bioclimatic variables with the corresponding altitude data, and seven spatially well-dispersed species occurrence records. Despite its narrow substrate specialization, Cyathus stercoreus is climatically quite plastic and is able to develop in a wide range of variations in mean annual temperatures and mean annual precipitation, which follows from the analysis of a two-dimensional niche based on two climatic variables using the Envelope method. Modeling the distribution of basidiomycete dung fungi using the Cyathus stercoreus as an example showed that the area of their potential distribution with a zone of favorable climate is very large. Most of the zone with a favorable climate is located in the area with the probability of the presence of species up to 70%. Cyathus stercoreus is not associated with any particular habitat type. On the territory of Russia, in the south of Siberia, the species is located on the northern border of its range in the area with the least favorable bioclimatic environmental factors.

Predicting Potential Habitat Distribution of Rauwolfia serpentina an Important Medicinal Plant using Maxent Modeling in Doon Valley, Uttarakhand State, India

The growing demand and dependencies of people for herbal care is time need. Among the list of various used herbal plants, Rauwolfia serpentina (Apocynaceae) is an important and due to relief of various central nervous system disorders. The root of this plant has been used in the treatment of hypertension or as a sedative and tranquillizing agent. This plant is variously used in Ayurveda, Unani system of medicine and Homeopathy for various disease ailments. Predicting potential geographic distribution of the species is important from species occurrence and habitat restoration point of view. This paper hearsay the results of a study carried out in the Dehradun valley in India (Dehradun surrounding forest area) on potential distribution modeling for Rauwolfia serpentina using Maxent model. The Worldclim bioclimatic variables, slope, aspect, elevation, and the FSI forest type data and 100 spatially well-dispersed species occurrence points were used to predict the potential distribution of Rauwolfia serpentina in ca. nearly 1277 km 2 of Doon valley study area. Jackknife test was used to evaluate the importance of the environmental variables for predictive modeling. Maxent model was highly accurate with a statistically significant AUC value of 88.5. The approach could be promising in knowing the eventing the potential distribution of medicinal plant species and thus, can be an effective tool in species restoration and conservation planning.

Maxent modeling for predicting the potential distribution of Sanghuang, an important group of medicinal fungi in China

Abstract The ability to identify the spatial distribution of economically important fungal species is crucial for understanding the environmental factors that affect them and for conservation management. A potentially valuable approach for this is maximum entropy (Maxent) spatial distribution modeling, which was applied here to map the potential distribution of three “Sanghuang” mushrooms in China, which include Phellinus baumii , Phellinus igniarius and Phellinus vaninii . Nineteen WorldClim bioclimatic variables, with corresponding altitude data, and 89 spatially well-dispersed species occurrence records were used in the modeling. The relative importance of the environmental variables was evaluated by Jackknife tests in the modeling analysis. The maximum entropy models obtained have high Area Under Receiver Operating Characteristic Curve (AUC) values: 0.956, 0.967 and 0.960, for P. baumii , P. igniarius and P. vaninii , respectively. The bioclimatic variable that most strongly affected distributions of P. baumii and P. vaninii was precipitation in the warmest quarter, while the mean temperature in the warmest quarter affected the distribution of P. igniarius most strongly. Overall, these models could provide valuable help in searching for the target species in areas where it is hitherto unknown, and be the reference of conservation measures for these medicinal fungal species.

Maxent modeling for predicting the potential distribution of medicinal plant, Justicia adhatoda L. in Lesser Himalayan foothills

The population of the medicinal plant, Malabar nut (Justicia adhatoda L.) is shrinking in Dun valley due to habitat fragmentation, invasion by Lantana camara, over-exploitation, and an ever-increasing human population – the most important being the increasing demand on land for agriculture, industries and the urbanization. Predicting potential geographic distribution of the species is important from species and habitat restoration point of view. This paper reports the results of a study carried out in the Lesser Himalayan foothills in India (Dun valley) on potential distribution modeling for Malabar nut using Maxent model. The Worldclim bioclimatic variables, slope, aspect, elevation, and the land use/land cover (based on IRS LISS-III) data and 46 spatially well-dispersed species occurrence points were used to predict the potential distribution of J. adhatoda in ca. 1877km2 study area. Jackknife test was used to evaluate the importance of the environmental variables for predictive modeling. Maxent model was highly accurate with a statistically significant AUC value of 92.3. The approach could be promising in predicting the potential distribution of medicinal plant species and thus, can be an effective tool in species restoration and conservation planning.

Shell-Dependent Evolution of Optical and Magnetic Properties of Co@Au Core–Shell Nanoparticles

Co@Au core shell nanoparticles (NPs) of different shell thicknesses were fabricated by a combination of the displacement process and the reduction–deposition process in a microfluidic reactor. Changes in the core sizes and the whole sizes of these Co@Au NPs with the shell formation were investigated. Effects of the shell thickness and the size change on the Co–Au interface pinning effects and the interparticle interaction were analyzed and correlated to their magnetic properties and surface plasmon resonance (SPR). Increasing the shell thickness causes an increase of the coercivity at 10 K due to the enhanced interfacial pining effect and decease of the coercivity at 300 K due to the reduced interparticle interaction. The increased core sizes and Co–Au interface pinning effects with the shell formation, and the higher interparticle interaction than that of well-dispersed species, result in significantly enhanced blocking temperature (Tb) for these Co@Au NPs. But the Tb's for these Co@Au NPs slightly decre...

THE DIVERSITY OF AUTOCHTHONOUS ROSES IN FLANDERS (BELGIUM) IN THE VIEW OF THE EUROPEAN GENEROSE REFERENCE FRAMEWORK

The subgenus Rosa is very intriguing but complex. Nowadays, many European taxonomists apply the taxonomical structure of Henker (2000), although other classifications and views are still considered. In order to gain insight in the taxonomical structure, 1,144 individuals belonging to 27 different wild rose species and some spontaneous hybrids were sampled in Belgium, France, Germany, The Netherlands and Scandinavian countries. Using AFLP analysis, the intra- and interspecific genetic variation was evaluated. PCO analysis supported the major subdivision of the subgenus Rosa in different sections and subsections according to Henker (2000). However, the position of R. tomentella in a separate subsection or within the subsection Caninae is questioned. In order to support the preservation and use of autochthonous genetic resources the genetic fingerprints of several populations were compared. It is concluded that wild populations of rare or locally prevailing species, accessioned from different regions, show genetic differentiation. However, for the common and well-dispersed species no differentiation was found.

Synthesis of platinum–tin/alumina reforming catalysts from a well-defined platinum–tin precursor complex

The complex [(CH 3) 4N] 3[Pt(SnCl 3) 5] was selected as a molecular precursor to prepare PtSn/γ c-Al 2O 3 reforming catalysts. The spectroscopic fingerprints of the starting complex were obtained by 195Pt and 119Sn NMR and diffuse reflectance UV–visible spectroscopy. A series of supported catalysts were synthesized by wet impregnation of alumina with a solution of the precursor in acetone. Well-dispersed species are obtained for Pt loadings below 1 wt.%; at higher loadings, a second species is formed that has spectroscopic features reminiscent of the initial complex and precipitates as a separate phase. Apparently, the Pt–Sn bonds are hydrolyzed in the low-loading species and preserved in the high-loading species. The thermal transformations of PtSn/γ c-Al 2O 3 catalysts are also studied and compared with those of the bulk precursor. In particular, it is shown that the nature of the atmosphere of thermal treatment (neutral or oxidizing) can orient the final catalyst towards preservation of an intimate Pt–Sn interaction, or towards demixtion.

The effect of the preparation method on the nature and dispersion of surface species formed upon reaction of molybdenum trioxide with alumina and titania

Titania- and alumina-supported molybdenum-containing systems have been prepared from mechanical mixtures of the support and molybdenum trioxide. The systems have been characterized by X-ray diffraction, temperature-programmed reduction and scanning electron microscopy, and Fourier transform-infrared monitoring of pyridine adsorption has been used to determine surface acidity. Dispersion of the supported phase, and its transformation to well-dispersed species has been attained by mechanical grinding and calcination in air, or by hydrothermal treatment of such mixtures and calcination. In the latter case, a higher dispersion is reached, despite the shorter time of calcination. Also hydrothermally treated samples show a larger concentration of surface Br6nsted acid sites.