Effectiveness of Nature Reserve System for Conserving Tropical Forests: A Statistical Evaluation of Hainan Island, China

<div><p>Evaluating the effectiveness of existing nature reserve systems for the conservation of tropical forests is an urgent task to save the remaining biodiversity. Here, we tested the effectiveness of the reserve system on Hainan Island by conducting a three-way comparison of changes in forest area in locations within the reserves, adjacent to the reserves, and far outside of the reserves. We used a general linear model to control for the effects of covariates (historical forest area, elevation, slope, and distance to nearest roads), which may also be correlated with the changes in forest area, to better explain the effectiveness of the reserve system. From 2000 to 2010, the forest area inside Hainan’s nature reserve system showed an increase while adjacent unprotected areas and the wider, unprotected landscape both experienced deforestation. However, the simple inside-outside comparisons may overestimate the protective effect of the reserve system. Most nature reserves (>60%) showed increasing fragmentation. And the risk of rapid deforestation remained high at low elevations, where remaining forests tend to be easily logged and converted to commercial plantations. Future conservation efforts should pay more attention to those sites with less challenging environmental conditions.</p> </div

Fate and Ecological Effects of Decabromodiphenyl Ether in a Field Lysimeter

Flame-retardant polybrominated diphenyl ethers (PBDEs) are environmental contaminants. Deca-BDE is increasingly used commercially, but little is known about the long-term fate and impact of its major component, decabromodiphenyl ether (BDE-209), on the soil environment. In this study, we investigated the fate and ecological effect of BDE-209 over 4 years in outdoor lysimeters in a field planted with a rice–wheat rotation. BDE-209 and six lower-brominated PBDEs (BDE-28, -47, -99, -153, -154, and -183) were detected in soil layers of the test lysimeter. We calculated an average BDE-209 migration rate of 1.54 mg·m^–2·yr^–1. In samples collected in May 2008, November 2008, November 2009, November 2010, and November 2011, 95.5%, 94.3%, 108.1%, 33.8%, and 35.5% of the spiked BDE-209 were recovered, respectively. We predicted the major pathway for debromination of BDE-209 in soil to be: BDE-209→BDE-183→BDE-153/BDE-154→BDE-99→BDE-47→BDE-28. In plants, BDE-209 and seven lower-brominated PBDEs (BDE-28, -47, -99, -100, -153, -154, and -183) were detected. BDE-100 was mainly derived from the debromination of BDE-154 in plants, but sources of other lower-brominated PBDEs were still difficult to determine. In soils containing BDE-209 for 4 years, soil urease activity increased, and soil protease activity slightly decreased. Our results provide important insights for understanding the behavior of BDE-209 in agricultural soils

Nature reserve system of Hainan Island.

<p>The nature reserve system, adjacent unprotected areas (surrounding lands within 10 km of the nature reserve boundaries) and wider unprotected landscape (more than 10 km away from the nature reserve boundaries) overlaid with natural forest cover in 2010 and digital elevation model (DEM) of Hainan Island, China.</p

Changes in tropical forests across Hainan Island.

<p>Changes in the area of tropical forests inside nature reserves, in adjacent unprotected areas (within 10 km of nature reserves’ boundaries), and in the wider unprotected landscapes (>10 km from nature reserves’ boundaries) in Hainan, China, from 2000 to 2010.</p

Mean forest area.

<p>Comparison of mean forest area (ha) between 2000 and 2010 across different sampling plots of 100 ha on Hainan Island (Group 1: inside nature reserves, Group 2: in adjacent 10-km unprotected areas, Group 3: in the wider unprotected landscape).</p>a<p>Wilcoxon Signed Ranks Test (2-tailed).</p

Composition-Driven Phase Boundary and Piezoelectricity in Potassium–Sodium Niobate-Based Ceramics

The piezoelectricity of (K,Na)­NbO₃ ceramics strongly depends on the phase boundary types as well as the doped compositions. Here, we systematically studied the relationships between the compositions and phase boundary types in (K,Na) (Nb,Sb)­O₃–Bi_0.5Na_0.5AO₃ (KNNS-BNA, A = Hf, Zr, Ti, Sn) ceramics; then their piezoelectricity can be readily modified. Their phase boundary types are determined by the doped elements. A rhombohedral-tetragonal (R–T) phase boundary can be driven in the compositions range of 0.035 ≤ BNH ≤ 0.040 and 0.035 ≤ BNZ ≤ 0.045; an orthorhombic-tetragonal (O–T) phase boundary is formed in the composition range of 0.005 ≤ BNT ≤ 0.02; and a pure O phase can be only observed regardless of BNS content (≤0.01). In addition, the phase boundary types strongly affect their corresponding piezoelectricities. A larger <i>d</i>₃₃ (∼440–450 pC/N) and a higher <i>d</i>₃₃* (∼742–834 pm/V) can be attained in KNNS-BNA (A = Zr and Hf) ceramics due to the involvement of R–T phase boundary, and unfortunately KNNS-BNA (A = Sn and Ti) ceramics possess a relatively poor piezoelectricity (<i>d</i>₃₃ ≤ 200 and <i>d</i>₃₃* < 600 pm/V) due to the involvement of other phase structures (O–T or O). In addition, the underlying physical mechanisms for the relationships between piezoelectricity and phase boundary types were also discussed. We believe that comprehensive research can design more excellent ceramic systems concerning potassium–sodium niobate

Giant Piezoelectricity and High Curie Temperature in Nanostructured Alkali Niobate Lead-Free Piezoceramics through Phase Coexistence

Because of growing environmental concerns, the development of lead-free piezoelectric materials with enhanced properties has become of great interest. Here, we report a giant piezoelectric coefficient (<i>d</i>₃₃) of 550 pC/N and a high Curie temperature (<i>T</i>_C) of 237 °C in (1–<i>x</i>–<i>y</i>)­K_1–<i>w</i>Na_<i>w</i>Nb_1–<i>z</i>Sb_<i>z</i>O_3–<i>x</i>BiFeO_3–<i>y</i>Bi_0.5Na_0.5ZrO₃ (KN_<i>w</i>NS_<i>z</i>-<i>x</i>BF-<i>y</i>BNZ) ceramics by optimizing <i>x</i>, <i>y</i>, <i>z</i>, and <i>w</i>. Atomic-resolution polarization mapping by Z-contrast imaging reveals the intimate coexistence of rhombohedral (R) and tetragonal (T) phases inside nanodomains, that is, a structural origin for the R–T phase boundary in the present KNN system. Hence, the physical origin of high piezoelectric performance can be attributed to a nearly vanishing polarization anisotropy and thus low domain wall energy, facilitating easy polarization rotation between different states under an external field

High-Entropy Strategy for Improved Mechanical and Energy Storage Properties in BaTiO₃–BiFeO₃‑Based Ceramics

Dielectric capacitors are employed extensively due to their exceptional performance, including a rapid charge–discharge speed and superior power density. However, their practical implementation is hindered by constraints in energy-storage density (ESD), efficiency (ESE), and thermal stability. To achieve domain engineering and improved relaxor behavior in 0.67BiFeO3-0.33BaTiO3-based Pb-free ceramics, the concerns have been addressed here by employing a synergistic high-entropy strategy involving the design of the composition of Sr(Mg1/6Zn1/6Ta1/3Nb1/3)O3 with B-site multielement coexistence and high configuration entropy. Remarkably, in (0.67-x)BiFeO3-0.33BaTiO3-xSr(Mg1/6Zn1/6Ta1/3Nb1/3)O3 ceramics with x = 0.08, a good ESE (η) of 75% and a recoverable ESD (Wrec) of 2.4 J/cm3 at 190 kV/cm were attained together with an ultrahigh hardness of ∼7.2 GPa. The high-entropy strategy, which is tailored by an increase in configuration entropy, can be attributed to the superior mechanical and ES properties. It also explains the enhanced random field and relaxation behavior, the structural coexistence of ferroelectric rhombohedral (R3c) and nonpolar pseudocubic (Pm-3m) symmetries, the decreased domain size, and evenly distributed polar nanoregions (PNRs). Moreover, improved thermal stability and outstanding frequency stability are also obtained. By boosting the configuration entropy, BiFeO3–BaTiO3 materials dramatically improved their complete energy storage performance. This suggests that designing high-performance dielectrics with high entropy can be a convenient yet effective technique, leading to the development of advanced capacitors

Table_1_Divergent Responses of the Diazotrophic Microbiome to Elevated CO2 in Two Rice Cultivars.PDF

<p>The species-specific responses of plant growth to elevated atmospheric CO₂ concentration (eCO₂) could lead to N limitation and potentially influence the sustainability of ecosystem. Questions remain unanswered with regards to the response of soil N₂-fixing community to eCO₂ when developing high-yielding agroecosystem to dampen the future rate of increase in CO₂ levels and associated climate warming. This study demonstrates the divergent eCO₂ influences on the paddy diazotrophic community between weak- and strong-responsive rice cultivars. In response to eCO₂, the diazotrophic abundance increased more for the strong-responsive cultivar treatments than for the weak-responsive ones. Only the strong-responsive cultivars decreased the alpha diversity and separated the composition of diazotrophic communities in response to eCO₂. The topological indices of the ecological networks further highlighted the different co-occurrence patterns of the diazotrophic microbiome in rice cultivars under eCO₂. Strong-responsive cultivars destabilized the diazotrophic community by complicating and centralizing the co-occurrence network as well as by shifting the hub species from Bradyrhizobium to Dechloromonas in response to eCO₂. On the contrary, the network pattern of the weak-responsive cultivars was simplified and decentralized in response to eCO₂, with the hub species shifting from Halorhodospira under aCO₂ to Sideroxydans under eCO₂. Collectively, the above information indicates that the strong-responsive cultivars could potentially undermine the belowground ecosystem from the diazotrophs perspective in response to eCO₂. This information highlights that more attention should be paid to the stability of the belowground ecosystem when developing agricultural strategies to adapt prospective climatic scenarios by growing high-yielding crop cultivars under eCO₂.</p

New Potassium–Sodium Niobate Ceramics with a Giant <i>d</i>₃₃

For potassium–sodium niobate, poor piezoelectric properties always perplex most researchers, and then it becomes important to attain a giant piezoelectricity. Here we reported a giant piezoelectric constant in (1 – <i>x</i>)­(K_0.48Na_0.52)­(Nb_0.95Sb_0.05)­O₃-<i>x</i>Bi_0.5Ag_0.5ZrO₃ lead-free ceramics. The rhombohedral-tetragonal phase boundary was shown in the ceramics with 0.04 < <i>x</i> ≤ 0.05, and then the ceramic with <i>x</i> = 0.0425 possesses a giant <i>d</i>₃₃ of ∼490 pC/N. We also discussed the physical mechanisms of enhanced piezoelectricity. As a result, such a research can benefit the sustainable development of (K,Na)­NbO₃ materials