Modelling the potential distribution of endangered Prunus africana (Hook.f.) Kalkm. in East Africa

Continued harvesting and climate change are affecting the distributions of many plant species and may lead to numerous extinctions over the next century. Endangered species are likely to be a special concern, but the extent to which they are sensitive to climate is currently unclear. Species distribution modelling, if carefully implemented, can be used to assess climate sensitivity and potential climate change impacts, of tree species. We used MaxEnt algorithm for species distribution modelling to assess the potential distribution and climate change risks for a threatened Prunus africana, in East Africa. Data from different herbaria on its distribution were linked to data on climate to test hypotheses on the factors determining its distribution. Predictive models were developed and projected onto a climate scenario for 2050 to assess climate change risks. Precipitation of driest quarter and annual precipitation appeared to be the main factors influencing its distribution. Climate change was predicted to result in reductions of the species' habitats (e.g. Erasmus et al., Glob. Change Biol. 2002; 8 : 679). Prunus africana distribution is thus highly vulnerable to a warming climate and highlights the fact that both in‐situ and ex‐situ conservation will be a solution to global warming.     

The African timber tree <Emphasis Type="Italic">Entandrophragma congoense</Emphasis> (Pierre ex De Wild.) A.Chev. is morphologically and genetically distinct from <Emphasis Type="Italic">Entandrophragma angolense</Emphasis> (Welw.) C.DC

Interpreting morphological variability in terms of species delimitation can be challenging. However, correcting species delineation can have strong implications for the sustainable management of exploited species. Up to now, species delimitation between two putative timber species from African forests, Entandrophragma congoense and E. angolense, remained unclear. To investigate their differences, we applied an integrated approach which combines morphological traits and genetic markers. We defined 13 morphological characters from 81 herbarium specimens and developed 15 new polymorphic microsatellite markers to genotype 305 samples (herbarium samples and specimens collected in the field across the species distribution ranges). Principal component analysis (PCA) of morphological data and the Bayesian clustering analyses of genetic data were used to assess differentiation between putative species. These analyses support two well-differentiated groups (F_ST?=?0.30) occurring locally in sympatry. Moreover, these two groups present distinct morphological characters at the level of the trunk, leaflets, and seeds. Our genetic markers identified few individuals (4%) that seem to be hybrids, though there is no evidence of genetic introgression from geographic patterns of genetic variation. Hence, our results provide clear support to recognize E. congoense as a species distinct from E. angolense, with a much lower genetic diversity than the latter, and that should be managed accordingly. This work highlights the power of microsatellite markers in resolving species boundaries.     

Anatomy,ultrastructure, and secretory activity of the floral nectaries in Swietenia macrophylla (Meliaceae)

• Premise of the study: While mahogany (Swietenia macrophylla) is one of the most important forest species in the Amazon region, little is known about its reproductive biology. Knowledge about the nectary structure and dynamics of nectar production of this species represent a key step toward understanding its relationship with pollinators. • Methods: Mahogany tree floral buds and flowers in anthesis were collected, fixed, and processed for study by light and transmission and scanning electron microscopy. The chemical composition of nectar and the nectary pigments was also studied. • Key results: Both staminate and pistillate flowers have nectaries, which contain a papillose epidermis and stomata. The nectariferous tissue is parenchymatous, with the cell cytoplasm primarily containing mitochondria and plastids. Secretory activity initiates at the beginning of anthesis, which occurs at nightfall. Flowers undergoing anthesis become structurally modified, with starch grains in the plastids disappearing. The number of plastoglobuli in the plastids also increases when nectaries change color from pale yellow to intense red. Pistillate and staminate flowers produce meager nectar rewards. • Conclusions: Changes in plastoglobuli number seem to be related to an increase in carotenes and color changes during anthesis. Carotenes can be linked to the protection of the plant against oxidative stress, which results from secretory activities. Nectary color has a limited role as a pollinator attractant. Floral rewards comprise small nectar droplets in both flower types, in addition to a few pollen grains in staminate flowers. These meager rewards are probably adapted to attract small generalist insects.     

Potential fishery of Nile perch Lates niloticus Linne (Pisces: Centropomidae) in Nyanza Gulf of Lake Victoria,East Africa

From bottom trawls, Lates niloticus (Lin.) in Nyanza Gulf was observed to have a gulf-wide distribution. Lates dominated the catch at Homa point. Catch rates in kg h^-1 varied from one location to another and from month to month.Its estimated production is 11 000 metric tons, netting about 22 000 000 Kenya shillings (US $2 000 000).Abundance of food items such as freshwater shrimps of the genus Caridina, and Engraulicypris argenteus, have been used as basis for estimating the growth and production of Lates.     

Restoration of genetic diversity in the dry forest tree Swietenia macrophylla (Meliaceae) after pasture abandonment in Costa Rica

We studied the levels of genetic diversity of Swietenia macrophylla (big leaf mahogany) in five successional plots in the Santa Rosa National Park, Guanacaste, Costa Rica. We selected sites with different lengths of time since the last major disturbance (typically fire): 6, 9, 15 and 20 years. In addition, we also included a patch of mature forest that had experienced selective logging and other human activity in the past 100 years. Genetic diversity was assessed using five polymorphic DNA microsatellite loci. We found a total of 21 alleles in the five loci examined, in which the number of alleles present varied among the five sites studied. Allelic diversity varied between sites ranging from 20 to 14 alleles, and our data revealed that earlier successional sites have more alleles than older sites. There was significant heterogeneity in allele frequencies between sites; however, genetic differentiation between populations was low (FST = 0.063) indicating that most of the variation was found within sites and extensive gene flow between sites. In addition, our analysis also showed that genetic diversity of adult trees does not solely determine the diversity of seedlings and saplings found around them, also supporting the existence of extensive gene flow. The impact of these findings for the design of conservation strategies for tropical dry forests trees is discussed.     

黄顶菊在中国的潜在适生区

菊科黄菊属植物黄顶菊近年出现在我国华北地区天津市和河北省的衡水、廊坊等地,其入侵范围有不断扩大的趋势.黄顶菊是一种入侵性极高的一年生杂草,对农牧业生态系统有极大的破坏性.为指导黄顶菊的防除和制定相关的控制政策,本研究根据黄顶菊在其原产地南美洲及扩散入侵地的分布资料,采用CLIMEX生态位模型对其在中国的潜在适生分布区域进行预测.结果表明,黄顶菊在中国的潜在适生区域集中分布于东南部的广东、广西、云南、海南、福建、台湾、江西、湖南、贵州、四川、重庆、湖北、安徽、江苏、上海15个省（市、自治区）,其中高风险区域包括广东、广西、台湾、海南、福建、云南、四川、贵州、重庆和西藏局部地区.     

Modelling the potential distribution of Mesalina watsonana (Stoliczka, 1872) (Reptilia: Lacertidae) on the Iranian Plateau

The Persian Long-tailed Desert Lizard, Mesalina watsonana, is one of the most common and most widely distributed lizards on the Iranian Plateau extending from Iran to Pakistan and Afghanistan. The species is frequently encountered in various types of habitats. We collected over 600 distributional records from available literature, museum collections, and our own field work and used bioclimatic and land cover characteristics to develop a model of potential distribution for M. watsonana. According to the model, the most important factors limiting the distribution of M. watsonana are: precipitation in wettest quarter exceeding 250–300 mm, precipitation in coldest quarter lower than 40 mm and exceeding 250 mm, altitudes above 2500 m and slopes steeper than 10.5°. The model suggests that most of the Iranian Plateau is suitable for the species except for some isolated areas such as the Dasht-e Kavir and Dasht-e Lut deserts in Iran, Helmand basin in Afghanistan, the Karakum Desert in Turkmenistan, the western Chagai-Kharan deserts of Pakistani Balochistan, and Thar and Cholistan deserts in eastern Pakistan. The most important factor in these regions appears to be the extremely low rainfall during coldest quarter of the year. The outer boundary of the distribution of M. watsonana follows important biogeographic barriers that are also clearly delimited by climatic conditions.     

Potential geographical distribution of Rhagoletis pomonella (Diptera: Tephritidae) in China

Abstract Apple maggot fly, Rhagoletis pomonella (Walsh) is a major pest causing considerable economic losses of fruits in North America. During the development of international trade, apple maggot fly has become a threat to Chinese agriculture. In this study, CLIMEX and ArcGIS were used to predict the potential geographical distribution of apple maggot fly in China. The parameters used in CLIMEX for apple maggot fly were derived from ecological data and the present geographical distribution of apple maggot fly in North America. Then the potential distribution map in China was presented based on the adjusted values of these parameters. The results showed that apple maggot fly has a wide potential distribution area in China; 47.5% of 748 meteorological stations presented high or medium suitability of pest establishment. These high suitable stations are mainly located in northeast, southwest and northwest of China, such as Liaoning, Shandong, Gansu and Shaanxi Provinces. These areas are also the central regions of apple, pear and peach production in China. Two hundred and twenty‐five stations (30.1%) in western and southern China, such as Tibet, Qinghai, Guangdong, Guangxi, Hainan and Taiwan, were unsuitable for establishment of apple maggot fly populations. In order to prevent the introduction of apple maggot fly in China, the present plant quarantine measures should be enhanced, especially in the areas with high suitability for the presence of apple maggot fly.     

栎方翅网蝽Corythucha arcuata(Say)在中国的潜在适生区预测

【目的】栎方翅网蝽是栎树上的一种重要害虫,自21世纪入侵意大利以来,迅速在欧洲地区暴发成灾。本文旨在探明栎方翅网蝽入侵中国的风险性。【方法】利用MaxEnt生态位模型预测栎方翅网蝽在中国的潜在适生区,分析栎方翅网蝽入侵、定殖和扩散的可能性。【结果】栎方翅网蝽入侵中国并在中国黄河长江中下游平原定殖和扩散的风险性极高,高度适生区包括重庆市、安徽省、湖北省、河南省、浙江省、湖南省、贵州省和四川省。通过分析环境因子重要性表明,最冷季度平均温度是影响栎方翅网蝽适应区的最关键环境变量;年平均温度、等温性和最干季度平均温度是影响栎方翅网蝽适应区分布的主要环境因素。【结论】栎方翅网蝽在我国定殖扩散风险高,建议植物检疫部门加强栎方翅网蝽的监控,并将栎方翅网蝽列入中华人民共和国进境植物检疫性有害生物名录。     

Normalizing sweet orange (C. sinensis (L.) osbeck) somatic embryogenesis with semi-permeable membranes

Summary Development of citrus somatic embryos initiated from embryogenic callus generally results in abnormal morphogenesis of somatic embryos. To normalize development, glycerol-induced globular-stage somatic embryos of sweet orange [C. sinensis (L.) Osbeck cv. ‘Hamlin’] were cultured on 6000–8000 MW cutoff cellulose acetate, >400 000 MW cutoff cellulose acetate, nitrocellulose, polyvinylidene fluoride (PVDF), cellulose filter paper, or positive or neutral charged nylon membranes. Only the two cellulose acetate membranes resulted in the development of normal, two-cotyledon, bipolar, heart-shaped embryos, and no aberrant teratoma-like structures. Heart-shaped embryos developed and germinated normally on Murashige and Tucker basal medium with 0.5% sucrose and 1 μM gibberellic acid. Culture of embryogenic callus directly onto cellulose membranes also resulted in the development of normal heart-shaped embryos, indicating that glycerol induction of globular-stage embryos is not necessary. Heart-shaped embryos were not observed when the osmotic potential of the medium was increased by the addition of 2.5–15% polyethylene glycol; neither were they observed when the matric potential of the medium was increased by increasing the gelling agent concentrations of agar and Gelrite from 0.8% to 3% and 0.15% to 0.9%, respectively.     

Typification of five names in Paracaryum (DC.) Boiss. (Boraginaceae)

Five names in the genus Paracaryum (DC.) Boiss. are lectotypified here: P. calycinum Boiss. & Bal. (endemic to Turkey), P. lithospermifolium (Lam.) Grande subsp. cariense (Boiss.) R. Mill var. cariense, P. kurdistanicum (Brand) R. Mill (endemic to Turkey), P. sintenisii Hausskn. ex Bornm., and P. strictum (C. Koch) Boiss.     

A Revision of the Species Walsura xizangensis C. Y. Wu et H. Li (Meliaceae)

A revision is made of the species Walsura xizangensis C. Y. Wu et H. Li found in Xizang. A new combination, Glycosmis xizangensis (C. Y. Wu et H. Li)D. D. Tao, is made.     

An assessment of the genetic diversity of Cedrela balansae C. DC. (Meliaceae) in Northwestern Argentina by means of combined use of SSR and AFLP molecular markers

Cedrela balansae C.DC. is a native tree species in Argentina, severely exploited for its timber features. We performed a molecular analysis to understand the genetic diversity and its distribution in eight remaining populations, which are distributed within the species' range in the Argentine Yungas Rainforest. We used two molecular markers: (i) seven SSRs, selected from forty-five SSRs developed for phylogenetically close species belonging to the Meliaceae family and (ii) 382 polymorphic AFLPs. The He was 0.643 and 0.222 for SSRs and AFLPs, respectively. The moderate levels of genetic diversity were related to the limited size of the species' distribution area, the latitudinal position of populations, the impacts of logging and the species' spatial distribution pattern. Genetic differentiation among populations was low for both markers (4.9% and 4.1% for SSRs and AFLPs, respectively). Four genetic clusters homogeneously distributed were distinguished. These observations may relate to the considerable historical gene flow measured (3.71 and 4.47 for SSRs and AFLPs, respectively). To safeguard the currently existing genetic base in the species, we identify four priority populations for conservation. To date only one of these is located in a protected area. Therefore, it is urgent to apply additional conservation measures for the remaining populations.     

Genetic diversity of Cedrela fissilis (Meliaceae) in the Brazilian Atlantic Forest reveals a complex phylogeographic history driven by Quaternary climatic fluctuations

Quaternary climatic fluctuations have shaped the geographic distribution of lineages, potentially affecting the demography, genetic structure, and patterns of genetic diversity of extant species. Different phylogeographic scenarios have been proposed for plants in neotropical cloud forests during the Last Glacial Maximum based on paleoecological data: the dry refugia hypothesis (DRH) and the moist forest hypothesis. We specifically focus on the Brazilian Atlantic Forest (BAF) range of Cedrela fissilis (Meliaceae), sampling 410 specimens from 50 localities. Our study combines analyses of the genetic diversity, phylogeographic patterns, and past geographic distributions with a particular focus on highland populations. We identified 283 alleles across the 11 microsatellite loci, ranging from 18 to 33 alleles per locus, distributed across five genetic groups. Most populations of C. fissilis from the BAF exhibited a diffuse genetic structure, reflected in low pairwise F_ST values, which could be the consequence of high gene flow. In addition, the plastid data showed a connection between the western, southern, and eastern populations in the North‐East of Brazil, but no association between genetic data and elevation was observed. Habitat suitability projections over the past 140 000 years showed less fragmentation relative to the present, indicating a higher connectivity and gene flow. Our results provide support for both the moist forest as well as the DRH, suggesting that most likely, a mixture of these processes has acted through space and time.     

基于MaxEnt模型的入侵植物白花鬼针草的分布预测及适生性分析

【背景】白花鬼针草为农区恶性杂草,原产于美洲,现已广泛分布于世界热带及亚热带地区,但其在全球和中国的适生区域及适生等级还不明确。【方法】利用MaxEnt生态位模型对白花鬼针草在全球以及中国的潜在适生区进行预测。【结果】白花鬼针草在全球的分布更多受到温度因素的影响。白花鬼针草的适生区主要集中在北半球和南半球15°~30°之间的热带和亚热带地区。其中,北美南部、南美中南部、非洲南部、东南亚北部以及大洋洲中南部沿海地区为白花鬼针草中、高度适生区。白花鬼针草在中国的适生区主要位于广东、广西、海南、云南、福建、台湾。到2070年,白花鬼针草在全球的适生区面积与当前相似,但在中国的适生区有所增大。【结论】白花鬼针草在我国有进一步扩张的风险。     

Potential spatial interaction of the invasive species Harmonia axyridis (Pallas) with native and endemic coccinellids

Biological invasions represent a serious menace to local species assemblages, mainly due to interspecific relationships such as competition and predation. One important invasive species worldwide is Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), which has invaded many regions of the world, threatening the native and endemic coccinellid assemblages due to negative interspecific interactions. These interactions have been widely studied at a local scale, but have been less studied at regional scales. Our aim was to estimate and analyse the potential spatial interaction associated with the co‐occurrence of H. axyridis with native and endemic species in Chile, considering bioclimatic and land cover variables. First, we created species distribution models (SDM) for H. axyridis, native and endemic coccinellids and six representative coccinellid species using maximum entropy technique. Then, we overlapped each SDM with land cover types to estimate the bioclimatic suitability within each land cover type. Finally, we identified the co‐occurrences of organisms according to the SDM and the land cover types, estimating in what land covers H. axyridis and the other coccinellids are more likely to co‐occur. Our results show that the suitable area for H. axyridis occurs from 30° to 42°S in Chile, while for native and endemic species this area is greater. The six selected species are mainly concentrated in central Chile, but differ in their potential suitable areas; Adalia angulifera Mulsant and Scymnus bicolor (Germain) have the largest range, and Mimoscymnus macula (Germain) has the most restricted one. The highest level of potential spatial interactions with H. axyridis occurs in central Chile, specifically in croplands and scrublands, and the lowest in primary native forest for all the species. Our results provide a spatially explicit baseline for coccinellid conservation and management of this invasive species.     

Male‐killer dynamics in Danaus chrysippus (L.) (Lepidoptera: Nymphalidae) in East Africa

Within certain regions in East Africa, the butterfly Danaus chrysippus (L.) shows female‐biased population sex ratio, because of the production by some females of all‐female broods, as a result of infection by maternally inherited, male‐killing bacterium of the genus Spiroplasma. In this study, we describe a 3‐year field survey for the population dynamics of the male‐killing Spiroplasma in D. chrysippus in four independent localities, namely Uganda, Ghana, Sudan and Madagascar. The prevalence of the bacterium was found to show extensive variations at multiple scales among different sites, in various countries, seasons and years. A novel, selection‐based hypothesis was suggested to explain the high variability of male‐killer prevalence over space and time, based on the existence of an adaptive link between larval food‐plant density and the magnitude of resource reallocation fitness advantage for the male‐killer.     

The nature of the interference potential ofPluchea lanceolata (DC) C B Clarke (Asteraceae)

The causes of the interference success of the weedPluchea lanceolata were studied. It was found that the weed achieves its success by inhibiting seed germination and seedling growth of different plant species through water-soluble phytochemical compounds synthesized by the weed and released by it in the soil.