Native Species Composition and Diversity of Valuable Woody Plants Regeneration during Fallow Period in Kamwatta, Moruca, Guyana

An intelligent method of shifting cultivation to regenerate vegetation after a long fallow period is critical information for restoration strategies. The literature review identified that the assessment of woody plant species on abandoned farmland has never been done before in Kamwatta, Moruca Region 1. In addition, more information should be available in indigenous communities and at the national level, including more documentation of the utilization of natural resources by the Warrau community. This study assessed the valuable woody plant species that grew during the fallow periods. Nine farmlands were randomly selected along a 100 m transect, each with varying fallow periods. In order to collect information on the age of farm abandonment, the researcher employed a mixed-methods approach. First, we found how long each farm had been fallow by administering a semi-structured questionnaire. Then, we conducted a flora survey to gain information on the variety and abundance of valuable plants using the age of farm abandonment as a dependent variable. The data analysis included the number of valuable woody trees with a diameter of >10 cm, seedlings and saplings with a diameter of <10 cm, the location of identified trees, and the uses of identified tree species. Microsoft Excel was used to code and analyze the questionnaire, while QGIS, Shannon’s Index of Diversity, and Simple Linear Regression were used to analyze the inventory data. The results showed that the respondents listed 38 valuable woody species, and 79% occurred in the studied area. The field verification revealed that the dominant family in the area was Mimosaceae. Species abundance increased with fallow up to 10 years before declining in the latter years. Plant diversity and abundance had a weak relationship with the age of abandoned farmlands for woody trees, while the seedlings and saplings showed no relationship.

Native Plants Can Help Conserve Water

这篇文章本来是针对美国读者的,但我们把它引介过来的目的是想让读者对美国的绿化状况有所了解。 Xeriscaping(无水绿化)对我们来说是个陌生的名词(欲探究其构词法的读者可在文中找到答案),可它对于维持生态平衡和节约水资源意义重大。因为about half the water we use in our homes is diverted to the lawn and gardenpatch,反过来,Done right,xeriscaping can cut landscape watering demandanywhere from 20 percent to 80 percent。由于国情不同,以上两句对我们来说不免生隔靴搔痒之感。但文中涉及的花卉栽培技术、选种(原产还是非原产)以及对喜干喜湿植物的判断等都提供了具体的指导,对于喜好侍花弄草的朋友是很有启发的。 生态环境恶化和资源危机业已得到全球人士的共识,美国人从身边绿化着眼,提出“无水绿化”的观点,方法简便易行,又着眼于生态大计,且惠泽子孙,他们这种务实的态度是值得我们学习的。

Accumulation behavior of heavy metals by Bidens pilosa L.from metallurgical slag:effects on plant physiology and absorption characteristics

Many of the abandoned mining and industrial land in villages and towns are seriously polluted by heavy metals in China,it is necessary for sustainable development to adopt efficient and economical ways to restore the ecology of abandoned mining and industrial land.Pollution level of topsoil contaminated with metallurgical slag from nonferrous metal smelting waste site in Baoding,North China and the heavy metals(HMs)accumulation behavior of Bidens pilosa L.(B.pilosa,native pioneer plant)were studied.Two selected study sites were mainly contaminated by As(270~434 mg/kg),Cd(63~95 mg/kg),Pb(5496~24504 mg/kg)and Zn(4500~21300 mg/kg),which exceed the national standard severely.Investigation of multi-metal accumulation in different parts of B.pilosa indicated that the absorption of toxic metals varied by types,concentration and species of HMs under stress conditions,soil property and plant tissues.The results showed that B.pilosa had excellent ability to accumulate HMs under different HMs stress condition,with the highest accumulation concentration of 85 mg/kg for As,380 mg/kg for Cd,4000 mg/kg for Pb,and 7500 mg/kg for Zn in roots under experimental conditions,respectively.The growth trend of B.pilosa declined with the increase of HMs stress concentration in tested soils.HMs stress led to different degrees of plant toxicity and obstruction of physiological metabolism.Among the plant physiological index,Chla and ChlT decreased 28.0%and 28.1%,37.3%and 35.5%under different stress treatments,respectively.Indicators related to physiological metabolic strength and stress resistance of plant,such as MDA(Malondiadehyde),CAT(catalase),SOD(superoxide dismutase)and SP(soluble protein),all increased with the increase of HMs stress concentration.

Reflection on Popular Concepts of Landscape Design

Guided by the values of harmonious coexistence between humans and nature,methods and concepts such as“biodiversity”,“sponge cities”,and“urban agriculture”have become popular.These methods and concepts are indisputable as a value orientation.But if conditional truth is promoted nationwide as unconditional truth,it will inevitably move from one extreme to the other.Starting from specific issues and practical experience,combined with the regional differences in the natural conditions,social customs and climate environment,the four popular viewpoints of“urban agriculture”,“biodiversity”,“local characteristics”,and“sponge cities”are reflected,and their“exclusion”reactions in certain regions are revealed,in order to awaken people’s rational thinking about popular concepts.

Arbuscular mycorrhizal fungal community assembly in the Brazilian tropical seasonal dry forest

Introduction:Here,we compare the arbuscular mycorrhizal fungal(AMF)community composition in soils from the root zone of the exotic invasive species Prosopis juliflora(EXO soils)and soils from the root zone of the native species Mimosa tenuiflora(NAT soils)from five locations in the Brazilian tropical seasonal dry forest,Paraíba,Brazil,using morphological analyses.Results:AMF community composition in EXO and NAT soils were dissimilar.Available phosphorus,diversity index,spore abundance,and species richness were the main factors differing between the EXO and NAT soils.In general,the most dominant order present in the soils were Glomerales(44.8%)and Gigasporales(41.4%).The most abundant AMF genus in all studied soils was Funneliformis.Conclusions:Differences in AMF community composition were associated with(1)differences in the dominant plant species(P.juliflora vs.M.tenuiflora)and(2)changes in soil chemical factors(soil,pH,total organic carbon,total nitrogen,and available P)in EXO soils.These results contribute to a deeper view of the AMF communities in exotic soils and open new perspectives for ecological processes involving AMF species and exotic plant species in the Brazilian tropical seasonal dry forest.