森林景观变化的地理环境因素整合分析——以伊洛河流域洛宁县为例

运用景观生态学的基本原理,借助于地理信息系统技术,整合分析了地理环境因素对伊洛河流域洛宁县森林景观动态变化的影响。结果显示,应用地理环境因素影响指数可以很好地从整体上分析地理环境因素,如高程、坡度、距离居民点中心的距离、与森林边缘距离等地理环境因子对区域森林景观动态变化的影响。1983和1999年,伊洛河流域洛宁县森林景观在地理环境因素影响指数上的优势分布区间(Pie1)分别为1230和1030,即在中高地理环境因素影响指数分布区间内,且有向低地理环境因素影响指数分布区间略为移动的趋势。森林景观类型保持不变部分、森林景观转化为非森林景观类型部分和非森林景观转化为森林景观类型部分所对应的在地理环境因素影响指数上的优势分布区间(Pie1)分别为1130、18和613。通过建立森林景观动态变化与地理环境因素影响指数的相互关系,表明森林景观动态变化与地理环境因素影响指数(特别是在地理环境因素影响指数的优势分布区间内)有显著相关关系。     

Updating the geographical distribution and frequency of Aedes albopictus in Brazil with remarks regarding its range in the Americas

The geographical distribution of Aedes albopictus in Brazil was updated according tothe data recorded across the country over the last eight years. Countrywide houseindexes (HI) for Ae. albopictus in urban and suburban areas were described for thefirst time using a sample of Brazilian municipalities. This mosquito is currentlypresent in at least 59% of the Brazilian municipalities and in 24 of the 27 federalunits (i.e., 26 states and the Federal District). In 34 Brazilian municipalities, theHI values for Ae. albopictus were higher than those recorded for Ae. aegypti,reaching figures as high as HI = 7.72 in the Southeast Region. Remarks regarding thecurrent range of this mosquito species in the Americas are also presented. NineteenAmerican countries are currently infested and few mainland American countries havenot confirmed the occurrence of Ae. albopictus. The large distribution and highfrequency of Ae. albopictus in the Americas may become a critical factor in thespread of arboviruses like chikungunya in the new world.     

Different responses of multispecies tree ring growth to various drought indices across Europe

Increasing frequency and intensity of drought extremes associated with global change are a key challenge for forest ecosystems. Consequently, the quantification of drought effects on tree growth as a measure of vitality is of highest concern from the perspectives of both science and management. To date, a multitude of drought indices have been used to accompany or replace primary climatic variables in the analysis of drought-related growth responses. However, it remains unclear how individual drought metrics compare to each other in terms of their ability to capture drought signals in tree growth.In our study, we employ a European multispecies tree ring network at the continental scale and a set of four commonly used drought indices (De Martonne Aridity Index, self-calibrating Palmer Drought Severity Index, Standardized Precipitation Index and Standardized Precipitation Evapotranspiration Index, the latter two on varying temporal scales) to derive species-specific growth responses to drought conditions. For nine common European tree species, we demonstrate spatio-temporal matches and mismatches of tree growth with drought indices subject to species, elevation and bioclimatic zone. Forests located in the temperate and Mediterranean climate were drought sensitive and tended to respond to short- and intermediate-term drought (<1 year). In continental climates, forests were comparably more drought resistant and responded to long-term drought. For the same species, stands were less drought sensitive at higher elevations compared to lower elevations. We provide detailed information on the month-wise performance of the four drought indices in different climate zones allowing users the selection of the most appropriate index according to their objective criteria. Our results show that species-specific differences in responses to multiple stressors result in complex, yet coherent patterns of tree growth.     

基于Landsat的重庆市生态环境质量动态监测及其时空格局演变分析

长江流域是我国重要的生态屏障之一,重庆市作为长江上游最后一道关口,研究其生态质量发展对于有效保护长江流域生态环境具有重要指导意义。基于2011—2021年间的Landsat影像等数据,计算遥感生态指数(Remote sensing based ecological index, RSEI),并采用Sen(Theil-Sen median)趋势分析法和MK(Mann-Kendall)检验研究其变化趋势以及利用Hurst指数模型分析RSEI的持续特征。利用空间转移矩阵和重心迁移模型研究其在空间上分布特征的变化情况,最后使用降水、风速、近地表气温、海拔等辅助数据为影响因素,结合地理探测器进一步探究RSEI变化驱动力,探讨重庆市2011—2021的RSEI空间分布及演变趋势。结果表明：(1)重庆市多年平均RSEI为0.593,使用等间距法将其划分的等级为差、较差、中等、良、优的面积占比分别为2.48%、8.28%、38.32%、41,87%、9.05%。从整体来看重庆市生态质量水平较高,重庆市年际RSEI以显著趋势波动增长。(2)RSEI等级为差的地区空间上主要集中于重庆西部;较差等级主要围绕...     

Trikatu,an herbal compound as immunomodulatory and anti-inflammatory agent in the treatment of rheumatoid arthritis – An experimental study

In the present study, trikatu, an herbal compound was evaluated for its immunomodulatory and anti-inflammatory properties with reference to cell mediated immune responses (delayed type hypersensitivity reaction), humoral immune response (haemagglutination titer and plaque forming assay), macrophage phagocytic index, circulating immune complex and inflammatory mediators in rats. For comparison purposes, indomethacin was used as a reference drug for anti-inflammatory studies. The results obtained in our study showed a significant decrease in cell mediated immune responses, humoral immune responses (haemagglutination titre and plaque forming assay) and macrophage phagocytic index in trikatu treated rats (1000 mg/kg/b.wt.) compared to control animals implying its immunosuppressive property. In addition, significant anti-inflammatory effects were observed in trikatu treated adjuvant induced arthritic rats by a reduction in the levels of circulating immune complexes and inflammatory mediators (TNF-alpha and Interleukin-1beta). Thus, in conclusion, our data suggest that trikatu could be considered as a potential anti-inflammatory agent for treating autoimmune inflammatory disorders like rheumatoid arthritis with immunosuppressive property.     

Self-fertility and associated flower head traits in the Iberian taxa ofLactuca and related genera (Asteraceae: Lactuceae)

Sexual reproduction is the main reproduction mechanism among the 14 wild Iberian taxa ofLactuca, Prenanthes, Cicerbita, andMycelis. High levels of self-fertilization occur inLactuca, as well as facultative and obligate xenogamy. Xenogamy is strongly correlated with large capitula having blue or bright yellow colouration, high P/O ratios, and long anthesis, whereas self-fertilization is correlated with smaller capitula having pale yellow colouration, small P/O ratios, and short anthesis. Large variations occur in P/O index among taxa showing similar fertilization mechanism, probably in relation to the number of florets included in flower heads. Interesting differences in reproductive systems have been detected between subspecies ofLactuca viminea.     

Environmental,geographical and time-related impacts on avian malaria infections in native and introduced populations of house sparrows (Passer domesticus), a globally invasive species

Aim

The increasing spread of vector-borne diseases has resulted in severe health concerns for humans, domestic animals and wildlife, with changes in land use and the introduction of invasive species being among the main possible causes for this increase. We explored several ecological drivers potentially affecting the local prevalence and richness of avian malaria parasite lineages in native and introduced house sparrows (Passer domesticus) populations.

Location

Global.

Time period

2002–2019.

Major taxa studied

Avian Plasmodium parasites in house sparrows.

Methods

We analysed data from 2,220 samples from 69 localities across all continents, except Antarctica. The influence of environment (urbanization index and human density), geography (altitude, latitude, hemisphere) and time (bird breeding season and years since introduction) were analysed using generalized additive mixed models (GAMMs) and random forests.

Results

Overall, 670 sparrows (30.2%) were infected with 22 Plasmodium lineages. In native populations, parasite prevalence was positively related to urbanization index, with the highest prevalence values in areas with intermediate urbanization levels. Likewise, in introduced populations, prevalence was positively associated with urbanization index; however, higher infection occurred in areas with either extreme high or low levels of urbanization. In introduced populations, the number of parasite lineages increased with altitude and with the years elapsed since the establishment of sparrows in a new locality. Here, after a decline in the number of parasite lineages in the first 30 years, an increase from 40 years onwards was detected.

Main conclusions

Urbanization was related to parasite prevalence in both native and introduced bird populations. In invaded areas, altitude and time since bird introduction were related to the number of Plasmodium lineages found to be infecting sparrows.     

Circadian effect of ACTH 1-17 on mitotic index of the corneal epithelium of BALB/C mice

The objective was to determine the effect of ACTH 1-17, an adrenocorticotropin analogue, on the mitotic index in the corneal epithelium of mice standardized in 12 hr of light alternating with 12 hr darkness. A question asked was whether the time of administration along the 24-hr time scale influenced any response found. The findings showed that ACTH 1-17 could, depending upon when it was administered, bring about a statistically significant decrease, an increase or even no such change in the mitotic index. The greatest responses found were increases, especially when ACTH 1-17 was administered during the dark span. Also the time after injection when the responses occurred varied. The greatest response recorded was at 12 hr after injection when ACTH 1-17 was given at 2 hr into the dark with a 641% and a 718% increase with a low (0.02 IU/kg) and a higher (20 IU/kg) dose, respectively. A 3-way analysis of variance supported the conclusion that the kind-of-treatment, time-of-treatment and treatment-to-kill interval (sampling time) are important factors when determining any response to ACTH 1-17 on the mitotic index.