Species distribution models applied to plant species selection in forest restoration: are model predictions comparable to expert opinion?

An expert on local flora usually is the best option for plant species selection in most ecological restoration projects; although species selection often needs to be dealt with swiftly as well as on a limited budget, and obtaining the opinion of a local expert may not always be an economically viable alternative. In such cases, species distribution models (SDM) may offer a faster and more cost effective alternative. We asked six experts to rank native tree species according to their suitability at 24 forest sites. The predictive performance of the suitability rankings was evaluated by assessing their ability to discriminate present from absent species in the observed tree assemblages at each evaluation site. We used the area under the receiver operating characteristic curve to calculate the probability that the estimated suitability for a species present at a particular evaluation site is greater than the estimate for an absent species (both picked at random). Suitability rankings were also obtained from the predictions of SDM and the same procedure was used to estimate the predictive performance of the set of models at each site. The experts offered concordant suitability rankings at almost every evaluation site. There were no significant differences in the predictive performance of the SDM and four of the experts, although the SDM performed slightly better than the other two experts. Our results point to the suitability of the proposed species distribution modeling approach to obtain fast and cost effective recommendations for species selection in forest restoration projects.     

Hydrology-oriented (adaptive) silviculture in a semiarid pine plantation: How much can be modified the water cycle through forest management?

Hydrology-oriented silviculture might adapt Mediterranean forests to climatic changes, although its implementation demands a better understanding and quantification on the water fluxes. The influence of thinning intensity (high, medium, low and a control) and its effect on the mid-term (thinned plots in 1998 and 2008) on the water cycle (transpiration, soil water and interception) and growth [basal area increment (BAI)] were investigated in 55-year-old Aleppo pine trees. Thinning enhanced a lower dependence of growth on climate fluctuations. The high-intensity treatment showed significant increases in the mean annual BAI (from 4.1 to 17.3 cm²) that was maintained in the mid-term. Thinning intensity progressively increased the sap flow velocity (v _s) in all cases with respect to the control. In the mid-term, an increased functionality of the inner sapwood was also observed. Mean daily tree water use ranged from 5 (control) to 18 (high intensity) l tree^?1. However, when expressed on an area basis, daily transpiration ranged from 0.18 (medium) to 0.30 mm (control), meaning that in spite of the higher transpiration rates in the remaining trees, stand transpiration was reduced with thinning. Deep infiltration of water was also enhanced with thinning (about 30 % of rainfall) and did not compete with transpiration, as both presented opposite seasonal patterns. The changes in the stand water relationships after 10 years were well explained by the forest cover metric. The blue to green water ratio changed from 0.15 in the control to 0.72 in the high-intensity treatment, with the remaining treatments in the 0.34–0.48 range.     

Dendrometric analysis of olive trees for wood biomass quantification in Mediterranean orchards

This work focuses on the development of dendrometric algorithms to calculate the volume and total biomass contained in olive trees. This laid the foundation for the use of this methodology as a tool to manage resources from orchards, establishing adequate prediction models for assessing other parameters such as income from raw materials from the cultivation, fruit production, CO₂ sinks, and waste materials (residual wood) used for energy or industry. Dendrometry has traditionally been applied to forest trees. However, little research has been conducted on fruit trees because of their heterogeneous structure. This issue was the first step of this research. For this, the form factors were calculated. This relates to the actual volume of the branch with a model volume, calculated as a revolution solid from the base diameter and length. The shape more approximated to 1 was the cylinder model with a mean value of 0.76 and standard deviation (SD) of 0.23. On the other hand, volume equations were obtained for the branches. The distribution of biomass in the tree was analyzed. It is estimated that 40 % of biomass is located in the stem and 60 % in the crown, and most of the crown biomass is concentrated in the first branches (60 %). Afterwards, occupation factors were calculated to relate the wood volume in the crown to its apparent volume, the mean being 0.005 dm³/m³ and SD 0.0025 dm³/m³. Also, equations for predicting the whole wood in the crown were obtained. In this regard, the best results were obtained when the crown diameter was used (R ² = 0.74). These results could be correlated with the production and quality of the fruit, amount of residual biomass coming from pruning, and LIDAR data, which may indicate a simple, quick, and accurate method for predicting biomass.     

Transferability of non-genic microsatellite and gene-based sunflower markers to safflower

Safflower (Carthamus tinctorius L.) DNA marker resources are currently very limited. The objective of this study was to determine the feasibility of transferring non-genic microsatellite (SSR) markers and gene-based markers, including intron fragment length polymorphism (IFLP) and resistance gene candidates (RGC)-based markers from sunflower (Helianthus annuus L.) to safflower, both species belonging to the Asteraceae family. Cross-species amplification of 119 non-genic SSRs, 48 IFLPs, and 19 RGC-based sunflower markers in 22 lines and germplasm accessions of safflower was evaluated. Additionally, 69 EST-SSR markers previously reported to amplify in safflower were tested. The results showed that 17.6% of the non-genic SSR, 56.2% of the IFLP, and 73.7% of the RGC-based markers were transferable to safflower. The percentage of transferable markers showing polymorphic loci was 66.6% for non-genic SSR, 70.6% for EST-SSR, 55.5% for IFLP, and 71.4% for RGC-based markers. The highest polymorphism levels were found for non-genic SSR. The average number of alleles per polymorphic locus and mean heterozygosity values were 2.9 and 0.46, respectively, for non-genic SSR, 2.2 and 0.35 for EST-SSR, 2.1 and 0.24 for IFLP, and 2.0 and 0.34 for RGC-based markers. The results of this study revealed a low rate of transferability for non-genic SSR sunflower markers and a better rate of transferability for IFLP and RGC-based markers. Transferable genic and non-genic sunflower markers can have utility for trait and comparative mapping studies in safflower.     

Photocatalytic Removal of the Antibiotic Cefotaxime on TiO<Subscript>2</Subscript> and ZnO Suspensions Under Simulated Sunlight Radiation

This study presents the main results about the removal of the antibiotic cefotaxime (CTX) under simulated sunlight radiation using heterogeneous photocatalysis with titanium dioxide (TiO₂) and zinc oxide (ZnO) in aqueous solutions. The effects of pH and catalyst initial load on pollutant removal were assessed considering the response surface methodology and a central composite circumscribed experimental design, which allowed to determine the optimized conditions that lead to a higher substrate elimination. Experimental results indicated that evaluated parameters have a significant effect on antibiotic removal in both TiO₂ and ZnO suspensions. In addition, the role of photogenerated holes, hydroxyl, and superoxide anion radicals on CTX degradation was evaluated to clarify the reaction mechanism. Finally, analysis of the dissolved organic carbon content in solutions and the antibacterial activity of treated samples showed that photocatalytic treatments were able to reduce a considerable portion of the organic matter present in the systems and its antimicrobial activity.     

Microwave l-band (1730 MHz) accurately estimates the relative water content in poplar leaves. A comparison with a near infrared water index (R1300/R1450)

In this study the estimation of reflectivity at 1730 MHz (l-band), measured with a microwave digital cordless telephony (DCT) patch antenna, is presented as an easy-to-handle and non-destructive new method to assess the relative water content (RWC) of poplar leaves and filter discs at different levels of dehydration. The accuracy of this new method has been contrasted with the R₁₃₀₀/R₁₄₅₀ index, determined by a portable near infrared (NIR) spectrometer. The close correlations found between RWC and the reflectivity at a frequency of 1730 MHz, both for filters and leaves, indicate that microwave determinations are rather independent of the physical properties of the material analysed. On the contrary, the differences found between poplar leaves and leaf filters in the relationships established between RWC and the R₁₃₀₀/R₁₄₅₀ index demonstrate a strong influence of the properties of the material in NIR reflectance measurements, specifically as they relate to changes in leaf thickness during dehydration. It should be noted that the amount of energy received by the leaf for the microwave technique (0.1 mW) was much lower than that received for the measuring of the R₁₃₀₀/R₁₄₅₀ index (2.5 W). Moreover, R-square coefficients were higher for microwaves than for the R₁₃₀₀/R₁₄₅₀ index. The use of a technologically simple, low cost and portable device, based on a microwave DCT patch antenna, could yield a solid support for the development of a commercial apparatus enabling the determination of plant water status under field conditions.