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1.
Invasive alien plant species such as Chromolaena odorata have negative impacts on biodiversity, ecosystem services and human well-being. Ecological impacts of this shrub are relatively well understood, but its impacts on local livelihoods and perceptions are poorly documented. We mapped C. odorata distribution in eastern Africa (Ethiopia, Kenya, Rwanda, Tanzania and Uganda) and compared perceptions and quantified the impacts of this species across Tanzanian villages with varying degrees of invasion density. Data were collected through 240 household questionnaires. Results indicate that C. odorata is a relatively new invader that already has severe negative impacts and is threatening livelihoods and the environment. Impacts include reductions in native biodiversity and the amount of available forage for livestock, reduced crop and water yields, and impaired mobility. Continued spread will cause additional negative impacts on poor rural communities. Implementation of a biological control programme targeting C. odorata is needed as a cost effective management approach along with other control and restoration measures.  相似文献   

2.
Globally, 10–20% of arid and semi-arid rangelands have been classified as severely degraded (UNCCD, in Elaboration of an International Convention to Combat Desertification in countries experiencing serious drought and/or desertification, particularly in Africa 1994; MEA, in Ecosystems and human well-being: current state and trends. Island Press, Washington, DC, 2005), and in sub-Saharan Africa specifically, 70% of rangelands are considered moderately to severely degraded (UNCCD 1994). Given that these drylands make up 43% of Africa’s land area and support approximately 45% of its population, restoring, maintaining and even increasing their productivity is imperative from both conservation and food security standpoints. In the Laikipia and Samburu counties of Kenya, degradation manifests itself through the increase of bare ground and the replacement of perennial grasses by undesirable plant species, primarily Acacia reficiens and Opuntia stricta, resulting in reduced forage availability. Further complicating management is the fact that most land in this ecosystem is owned by community conservancies, where the land is managed to support both wildlife and livestock grazing. There has been considerable effort targeted towards using mechanical clearing coupled with reseeding to combat A. reficiens spread. Additionally, the use of both traditional and modern mobile cattle enclosures (commonly referred to as bomas) has been used to create vegetation patches in areas with increasing bare ground. Here, we look at the challenges faced in implementing these interventions, as well as the successes and opportunities associated with them.  相似文献   

3.
Callus from Opuntia streptacantha (cv. Tuna loca), Opuntia megacantha (cv. Rubí reina), and Opuntia ficus-indica (cv. Rojo vigor) were exposed to jasmonic acid (JA) and abiotic stress (drought and UV light) to improve the metabolite production. The callus growth curves, phenolic acids and flavonoids content, antioxidant activity and phenylalanine ammonia lyase (PAL) activity were analyzed under normal and stress conditions. In O. streptacantha callus, the phenolics concentration increased 1.6 to 3 times times in presence of 5% PEG or after irradiation with UV light for 240 min, respectively, while flavonoids triplicate with UV light. A significant increase in antioxidant activity was observed in calli from the three Opuntia species in media with 50 µM JA. The relationships between metabolites/PAL activity, and metabolites/antioxidant activity were analyzed using a surface response methodology. Results showed that PAL activity, induced with PEG and UV, correlated with flavonoids content in O. megacantha and O. ficus-indica calli; PAL activity was related to both flavonoids and phenolics compounds in O. ficus-indica and O. megacantha calli exposed to JA, but only to flavonoids in O. streptacantha callus. In general, the JA stimulated simultaneously the metabolic pathways for phenolics and flavonoids synthesis, while abiotic stress induced mainly flavonoids route. As the stressed Opuntia calli exhibited as high antioxidant activity as cladodes, they are a promising system for research on antioxidant biosynthesis and/or to identify new compounds with antioxidant properties.  相似文献   

4.
The Opuntia (prickly pear) genus, an important horticultural crop in Mexico, is essentially a fruit crop with two variants: sweet (“tunas”) or acid (“xoconostles”) fruits; it is also a source of vegetables “nopalitos” or fodder for livestock, among other uses. Its taxonomical classification has been reported as complex, although few studies on the genetic structure of Mexican Opuntia are available, and genetic differences between the two types of fruits are unknown. Opuntia genotype identification and classification are still mainly based on morphological characters. In this study, the genetic diversity of Mexican Opuntia germplasm with agronomic and economic importance was revealed, using 88 accessions and 13 SSR markers, in an attempt to explore the genetic relationships among them. A total of 159 alleles were detected ranging from 7 to 23 per locus with an average of 12.2. The SSR markers generated unique fingerprints for each Opuntia accession confirming their usefulness for genetic analysis. The accessions’ grouping was defined by several complementary clustering methods, and the moderate incongruences between the different methods did not influence the overall clustering. DAPC and STRUCTURE analyses grouped the accessions into five groups, thus confirming the incorrect delimitation of species in this genus. The following species had no clear boundaries: Opuntia ficus-indica, Opuntia albicarpa, Opuntia megacantha, Opuntia streptacantha, Opuntia lasiacantha, and Opuntia hyptiacantha. However, Opuntia robusta was separated from the rest of the species. Opuntia joconostle and Opuntia matudae, which produce acid fruits, tended to differ from the others. Median-joining simulation classified all genotypes into a complex network, and both linear and reticular ties between Mexican Opuntia genotypes were revealed. The genetic distance revealed in the present study shows the importance of Mexican accessions for conservation and use in breeding programs.  相似文献   

5.
6.
Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an invasive species present in numerous agroecosystems in North America. Despite adverse impacts as a threat to native biodiversity, a nuisance household invader and a pest in fruit production, H. axyridis also plays a beneficial role as a major component of assemblages of generalist predators in several agricultural crops. Here, we review the role of H. axyridis as a natural enemy of Aphis glycines Matsumura (Hemiptera: Aphididae), an invasive pest of soybean, Glycine max (L.) Merrill (Fabales: Fabaceae), in North America. Harmonia axyridis is often the most abundant predator species attacking A. glycines in soybean agroecosystems. This predator has the potential to both prevent and suppress A. glycines outbreaks. Further studies are needed to fully understand and utilize the potential of H. axyridis as a natural enemy in the management of A. glycines and other agricultural pests in agroecosystems worldwide.  相似文献   

7.
A new species of Stemodia (Plantaginaceae) from the Caatinga of northern Minas Gerais, Brazil, is described and illustrated. Stemodia perfoliata was first collected by Auguste de Saint-Hilaire, ca. 200 years ago, and remained unnamed until now. The new species is characterized by the connate-perfoliate leaves, a unique feature in the genus. We provide notes on morphology, geographic distribution and conservation status of S. perfoliata, along with a key to differentiate it from the similar species that occur in Brazil: S. durantifolia, S. hyptoides, S. maritima, S. palustris and S. stricta.  相似文献   

8.
The subgenus Pocusogetus Rtt. of the genus Otiorhynchus Germ. is revised. The subgenus includes O. rosti Strl., O. shapovalovi Davidian et Yunakov, O. obsulcatus Strl., O. fischtensis Rtt., and O. gusakovi sp. n. closely related to O. fischtensis (both from Mt. Fisht, the Western Caucasus). O. fischtensis is transferred from the subgenus Vicoranius Rtt., its lectotype is designated. A key to species of Pocusogetus is given. The systematic position of the subgenera Pocusogetus and Vicoranius in the genus Otiorhynchus is discussed. New data on the geographical distribution and ecology of the little-known species of the subgenera Obvoderus Rtt., Pseudoprovadilus Magnano, and Clypeorhynchus Yunakov et Arzanov are given. Some features of ecological differentiation between Otiorhynchus species in the alpine and subalpine zones of the Caucasus are discussed.  相似文献   

9.
A multivariate analysis of 11 skull measurements, along with evaluation of the shape of maxill-premaxill suture at palatine foramina, was carried out in pikas of thealpina-hyperborea group. The study provided rational for recognition of three distinct species in this group:Ochotona alpina (Pallas, 1773),O. hyperborea (Pallas, 1811), andO. turuchanensis Naumov, 1934.O. turuchanensis is a species from central Siberia differing fromO. hyperborea in the chromosome number and type of palatine foramina and fromO. alpina in size of the skull. This species is allopatric withO. alpina and partly sympatric withO. hyperborea. The subspeciessvatoshi is reportedly allocated toO. hyperborea. The taxonomic status ofmantchurica (now allocated tohyperborea) and scorodumovi (treated at present as an isolated subspecies of O. alpina) needs careful investigation.  相似文献   

10.
Striga hermonthica is a hemiparasitic weed that causes huge grain yield losses to small-scale farmers in Africa. Effective biocontrol agents against S. hermonthica can sustainably mitigate these losses. This study characterized the biocontrol potential of culturable fungal and bacterial isolates from S. hermonthica suppressive soils of western Kenya. These isolates were screened for their ability to produce antibiotic compounds and extra cellular enzymes and also their ability to cause S. hermonthica seed decay. Genomic DNA of the selected bacterial and fungal isolates was extracted and partial characterization of 16S rRNA and 18S rRNA genes performed respectively. Analysis show that antibiosis and enzymatic properties of potential biocontrol isolates correlated positively. Isolate KY041696 recorded high antibiosis, enzymatic and seed decay values. This study also revealed that bioactive bacterial isolates belonged to Bacillus, Streptomyces and Rhizobium genera. In this study, no fungal isolate caused S. hermonthica seed decay. This study therefore provides baseline information on the potential biocontrol microbes against S. hermonthica in Western Kenya that could be exploited further in the management of the weed.  相似文献   

11.
In the summer and autumn of 2017, two mostly Southeastern European weevils Otiorhynchus albidus Stierlin, 1861 and O. asphaltinus Germar, 1824, and also O. rotundus Marseul, 1872, previously unknown from Russia, were found in numbers on Syringa vulgaris L. and S. josikaea Jack. in St. Petersburg. New data on the distribution of O. smreczynskii and a key for differentiation of O. rotundus, O. smreczynskii and closely allied to the latter O. ukrainicus Korotyaev, 1984 from southeastern Ukraine and eastern Crimea are reported.  相似文献   

12.
Data on 15 species of the subgenus Pseudotiorhynchus Magnano, 2004 of the genus Otiorhynchus Germar, 1822 from Kazakhstan, Turkmenistan, and Iran are given. Otiorhynchus lukarevskayae Davidian, sp. n., O. karakalensis Davidian et Savitsky, sp. n., O. konstantini Davidian et Savitsky, sp. n., O. muratovi Savitsky et Davidian, sp. n., O. kopetdagicus Savitsky et Davidian, sp. n., and O. shakhensis Savitsky et Davidian, sp. n. from Turkmenistan, and O. khorasanus Savitsky et Davidian, sp. n. from Iran are described as new to science. A new synonymy is established: Pseudotiorhynchus Magnano, 2004 = Crassorhynchus Magnano, 2004, syn. n. Otiorhynchus iranensis Magnano, 2004 is transferred from the subgenus Protarammichnus Voss, 1960 to the subgenus Pseudotiorhynchus. Lectotype of O. conicirostris Stierlin, 1886 is designated. A key to 15 species of the subgenus Pseudotiorhynchus is given. The new subgenus Microhanibotus Savitsky et Davidian, subgen. n. is established for the new species O. ghilarovi Davidian et Savitsky, sp. n. from the Western Kopet Dagh in Turkmenistan. Microhanibotus subgen. n. is closely related to the subgenera Pseudotiorhynchus, Hanibotus Reitter, 1912 and Nubidanus Reitter, 1912.  相似文献   

13.
The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a damaging pest of citrus globally and has recently been detected in Tanzania. Although direct damage by the pest is seldom of economic importance, the insect is more notorious for its ability to vector the fastidious phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas), the putative causal bacterium of Huanglongbing or Asian citrus greening disease. For many years, Trioza erytreae (Del Guercio) (Hemiptera: Triozidae) was known to be the main vector of the African citrus greening disease caused by Candidatus Liberibacter africanus (CLaf), but the recent arrival of D. citri on the continent adds to the dynamics of infection and spread of both diseases on mainland Africa. Following the recent report of the presence of D. citri in Tanzania, an additional delimiting survey was carried out in the region, focusing on Kenya, mainland Tanzania and Zanzibar to detect the presence and ascertain the extent of spread of D. citri. We employed molecular tools based on the use of DNA barcoding to confirm the identity of D. citri. In addition to D. citri, the occurrence of T. erytreae in the same sampling locations is also reported. Adults and nymphs of either D. citri or T. erytreae were collected from citrus at many of the surveyed sites ranging from 19 to 668 m above sea level (masl) in Tanzania, 20–1666 masl in Kenya, and 42–48 masl in Zanzibar. Diaphorina citri was sympatric with T. erytreae at the mid to higher elevations of 1375–1666 masl and no T. erytreae or its open-gall symptoms were detected below 523 masl. Sequences obtained were queried via BLAST and all linked to D. citri of different accession numbers already available on GenBank. This is the first report of the presence of D. citri in Kenya and Zanzibar. The potential implication of the detection and spread of the two pathogens, CLaf and CLas to the citrus industry in East Africa and movement of suitable host plants is discussed.  相似文献   

14.
15.

Background

Edible insects are an important source of food to many African populations. The longhorn grasshopper, Ruspolia differens (Serville 1838), commonly known as senene in Tanzania is one of the most appreciated edible insects by societies around Lake Victoria crescent. Senene is primarily an essential treat for the tribes around the lake, e.g., the Haya of Tanzania, Luo of Kenya and Baganda of Uganda. Despite its importance as a food item and appreciation as a delicacy, there are few studies dealing with culture, beliefs and indigenous technology in connection with the senene. The main objective of this study was to survey indigenous technologies, processing methods and traditions in relation to senene consumption among the Haya tribe in Kagera region of Tanzania.

Methods

Our ethnographic study was conducted through semi-structured interviews. A total of 51 locals, 26 females and 25 males aged 21 to 60 years were interviewed (with 3 female and 7 male key informants among them). Questions focused on cultures, beliefs and traditions towards senene consumption. Processing, preservation and shelf-life as well as nutritional knowledge were also investigated.

Results

Harvesting for household consumption was mainly done through wild collection. Traditionally made traps were mostly used for commercial harvesting. Deep frying was the most preferred processing method while smoking was the most preferred preservation method, with shelf-life of up to 12 months. Interesting traditions and taboos associated with senene consumption were identified, with men monopolising the insects as food by declaring the insects taboo for women and children. Deep fried senene in locally packed containers were mostly sold by street vendors, but also available from a variety of stores and supermarkets.

Conclusion

Beyond being just an important traditional delicacy, senene is becoming increasingly popular, providing opportunity for local businesses. Indigenous technologies for harvesting, processing and preserving senene exist, but must be improved to meet food processing standards, thereby promoting commercialization. This carries economic potential essential for improving incomes and livelihoods of women and smallholder farmers, improving household level food security.
  相似文献   

16.
Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) oviposits in ripening fruit, larvae render crops unmarketable, and significant economic losses can occur. Biological control research has focused on individual natural enemy species against immature D. suzukii. Here we combine two predators and an entomopathogenic nematode, expecting species complementarity and increased control of D. suzukii. In strawberries, Orius insidiosus (Say) (Hemiptera: Anthocoridae) plus Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) resulted in fewest D. suzukii (81% reduction), and in blueberries, results were similar (60% reduction), although H. bacteriophora was not as effective as in strawberries, which was likely due to drier substrate conditions. There was neither strong complementarity nor interference between predators, O. insidiosus and Dalotia coriaria Kraatz (Coleoptera: Staphylinidae). Inclusion of O. insidiosus resulted in 50% fewer D. suzukii than combinations without O. insidiosus. Control of D. suzukii can be improved with multiple natural enemies, and combinations of O. insidiosus with other agents (parasitoids, fungal entomopathogens) should be tested.  相似文献   

17.
Many species of the butterfly genus Phengaris are regarded as endangered in many parts of their distribution. Several species are also widely distributed across northern China. Due to land use change and overgrazing, their habitats are declining and many patches have been lost. This paper investigates the distribution and habitats of the Chinese Phengaris species (of the subgenus Maculinea). Shrub-grassland near forests seem the most frequent habitat for Phengaris, while flat open grasslands are mostly over-grazed and thus survival for Phengaris butterflies there seems difficult. Throughout Europe, P. teleius is an endangered species, while there is still no information on its status in China. To improve the knowledge on the population ecology of P. teleius, its population structure, adult behaviour and movement were studied through mark–release–recapture methods in the Qinling Mountains of Taibai County. Eight grassland patches which were potentially suitable were found in the area in 2013. In total, 480 individuals (274 females) were marked, resulting in an overall recapture rate of 16 %. The average daily population size was 44 butterflies (±23 SD) during the adult flight period. Sixty-seven percent of the females and 38 % of the males moved less than 50 m, and 17 % of recaptured females and 38 % of males moved more than 200 m. The mean movement distance was 107 ± 177 m for males and 182 ± 122 m for females. The majority of the recaptures (86 %) were made within the patches, only a few individuals (14 %) moved between patches. Due to human disturbance and destruction, all of the eight potentially suitable patches are becoming smaller and increasingly isolated, thus these populations of P. teleius may face an increasing risk of extinction, which may well be a tip of the iceberg of habitat loss and fragmentation of P. teleius in Taibai County and possibly beyond. Hence we hope our initial study of P. teleius could have positive impacts on the conservation of Phengaris butterflies in China.  相似文献   

18.
We typify and clarify the nomenclature and identity of three species originally described in the fern genus Pellaea. We find Pellaea bongardiana to be illegitimate and recognize it as a synonym of Ormopteris riedelii (= P. riedelii). We also consider Pellaea brasiliensis to be a synonym of O. riedelii. The phylogenetic position of Pellaea flavescens, recently combined in Ormopteris (as O. flavescens), is discussed, and a key to all species of Ormopteris in Brazil is provided.  相似文献   

19.
Beaucarnea (Nolinaceae) is a Mexican and Guatemalan genus that inhabits dry tropical areas. Most of the species are endangered under the Mexican legislation because they have a high horticultural demand and are threatened by habitat destruction. Species are difficult to recognize, since their differences are a mixture of trunk, inflorescence and fruit characters frequently absent in herbarium specimens. The aim of this work is to describe the foliar anatomy of the 11 species of Beaucarnea in search of characters with taxonomic value to sustain the generic subdivision, and to provide a key for specimens determination based on leaf and growth form. We found that four species (B. compacta, B. gracilis, B. purpusii and B. stricta) have a grooved leaf outline in transverse section, whereas the rest of the species are undulated. Other characters, such as epicuticular waxes, stomatal distribution and density, marginal teeth length and leaf apex provide valuable characters for species determination.  相似文献   

20.
Three new species of the genus Otiorhynchus Germar, 1822 are described from the Caucasus: O. titarenkoi sp. n. in the subgenus Motilacanus Reitter, 1912 and O. dittae sp. n. and O. zierisi sp. n. in the subgenus Eprahenus Reitter, 1912. The incivilis species-group is transferred from the subgenus Choilisanus Reitter, 1912 to the subgenus Eprahenus (new subgeneric placement).  相似文献   

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