Indigenous burning shapes the structure of visible and invisible fire mosaics

Landscape Ecology - In many regions of the world, Indigenous people continue to shape landscape patterns using fire. Some studies show that Indigenous fire regimes create a diverse “visible...     

Correlations between quantitative tree and fruit almond traits and their implications for breeding

Correlations between 29 quantitative tree and fruit traits were studied in 46 almond genotypes and some inter-specific crosses. Results reflected a significant diversity in the assayed almond germplasm. In addition, the obtained cluster demonstrated varying degrees of relationships, illustrating higher correlation values for the flowering traits and lower correlation values for the nut and kernel traits. To determine the importance of the traits and the levels of similarity existing between the various studied traits, a discriminate analysis was carried out. According to the results obtained from these analyses, the different traits were discriminated on basis of the characteristics of the presence of double kernels, the nut and the kernel size, the flowering date, kernel yield and shelling percentage. Finally, this study evidenced correlations between most of the agronomic traits in almond, although the correlations coefficient (r) value was found to be higher than 0.5 only in some cases. This analysis can help breeders for choosing the most favorable entries to build a core subset of the almond collection for the purpose of breeding.     

Multi-scale responses of bird species to tree cover and development in an urbanizing landscape

Landscape change is an ongoing process for even the most established landscapes, especially in context to urban intensification and growth. As urbanization increases over the next century, supporting bird species’ populations within urbanizing areas remains an important conservation challenge. Fundamental elements of the biophysical structure of urban environments in which bird species likely respond include tree cover and human infrastructure. We broadly examine how tree cover and urban development structure bird species distributions along the urban-rural gradient across multiple spatial scales. We established a regional sampling design within the Oak Openings Region of northwestern, Ohio, USA, to survey bird species distributions across an extensive urbanization gradient. Through occupancy modeling, we obtained standardized effects of bird species response to local and landscape-scale predictors and found that landscape tree cover influenced the most species, followed by landscape impervious surface, local building density, and local tree cover. We found that responses varied according to habitat affiliation and migratory distance of individual bird species. Distributions of short-distance, edge habitat species located towards the rural end of the gradient were explained primarily by low levels of urbanization and potential vegetative and supplemental resources associated with these areas, while forest species distributions were primarily related to increasing landscape tree cover. Our findings accentuate the importance of scale relative to urbanization and help target where potential actions may arise to benefit bird diversity. Management will likely need to be implemented by municipal governments and agencies to promote tree cover at landscape scale, followed by residential land management education for private landowners. These approaches will be vital in sustaining biodiversity in urbanizing landscapes as urban growth expands over the next century.     

Correlations and variance among species traits explain contrasting impacts of fragmentation and habitat loss on functional diversity

Landscape Ecology - Understanding how landscape fragmentation affects functional diversity, defined as the distribution of functional traits in an assemblage, is critical for managing landscapes...     

间伐干扰对人工林林木生长、幼苗更新及植被多样性的影响

抚育间伐是森林经营的重要措施之一,合理的间伐可以优化林分结构,改善林下环境,提高森林生产力和稳定性。本研究以河北省塞罕坝机械林场华北落叶松人工林和樟子松人工林为对象,对比分析间伐和未间伐林分（自然保护区）中林木生长、物种多样性和天然更新的差异。结果表明,间伐区华北落叶松人工林胸径年均增长0.72 cm,比未间伐区提高53.2%;间伐区樟子松人工林胸径年均增长0.59 cm,比未间伐区提高25.5%。间伐区内Shannon-Wiener指数、Simpson多样性指数、Pielou均匀度指数和Margalef丰富度指数较未间伐区分别高出159.2%、185.3%、185.9%和108.4%。间伐区幼苗幼树的更新种类和数量明显高于未间伐区,其中,樟子松人工林间伐区幼苗幼树的更新种类和数量均高于华北落叶松人工林。可见,对自然保护区内未经营过的人工林进行适当抚育间伐对提高森林生产力、维持生物多样性和促进森林正向演替有重要作用。     

Interactions between landscape structure and animal behavior: the roles of heterogeneously distributed resources and food deprivation on movement patterns

To examine how resource distributions affect the movement behaviors of fed and food-deprived Eleodes extricata Say darkling beetles (Coleoptera: Tenebrionidae), we experimentally manipulated the dispersion of food to create clumped, random, and uniform distributions in an otherwise homogeneous 25-m² experimental field landscape. Quantitative measures of the tortuosity, net linear displacement, overall path length, and velocity of beetle movement pathways showed that food-deprived beetles generally moved more slowly and over shorter distances than did fed beetles. This effect was mediated by the spatial distribution of food, however; food distributed randomly over the landscape evoked more tortuous paths over larger overall distances. The foraging movements of food-deprived beetles were most different from those of fed individuals in treatments with randomly distributed food resources. These results show that the influence of spatial structure on individuals depends not only on the arrangement of pattern but also on the function that the structure plays. Thus, 'spatial structure' is defined not only by physical characteristics of the landscape but also by how that structure is used by animals.     

Multi-scale mismatches between urban sprawl and landscape fragmentation create windows of opportunity for conservation development

Context

Urban sprawl and the expanding transportation infrastructure drive land consumption and landscape fragmentation, causing environmental deterioration and loss of species. Current understanding of how these drivers interact to shape landscape fragmentation is still poor. However, a strong correlation between urban sprawl and landscape fragmentation patterns is commonly assumed.

Objectives

Our main objective was to test the strength, non-stationarity, and scale-dependency of the relationship between urban sprawl and landscape fragmentation patterns (‘sprawl-fragmentation relationship’). Subsequently, we propose an extended framework for the links between urban sprawl, expansion of transport infrastructure, and landscape fragmentation.

Methods

We quantified spatial patterns of urban sprawl and landscape fragmentation for mainland Spain at multiple scales. We then fitted global regression models and geographically weighted regression models with metrics of landscape fragmentation and urban sprawl.

Results

Most variation in landscape fragmentation values (almost 80 % on average) is not explained by urban sprawl metrics through global modeling. Local models show substantial improvements in model performance, with an average of 37 % of the variance remaining unexplained. The contribution of urban sprawl to landscape fragmentation patterns varies locally and depends on scale, with higher contributions at coarser scales and at higher organizational levels.

Conclusions

Our investigation revealed three critical characteristics of the sprawl-fragmentation relationship: it does not prevail, is non-stationary, and scale-dependent. We propose four mechanisms that may have resulted in this mismatch: scale, time-lagged development, spatial arrangement of development, and other external variables including teleconnections. These spatial mismatches provide windows of opportunity for conservation through better development strategies.

     

改善树体结构对提高龙眼产量和品质的影响试验

通过培育不同树形,并对郁闭的龙眼果园进行疏枝、间伐试验。结果表明,建立高光效树体结构,减少郁闲果园株数,能有效改善果园通风透光条件、提高产量和果实品质;林华果场试验因疏枝改造后树高降低,冠径扩大,单株产量比对照增加121kg,果实品质显著提高;密龙果场试验园间伐后,虽然总产量略有降低,但是667m2产值比对照增加687．8元。通过调查不同果园的龙眼产量和树体结构,得到龙眼产量与树体结构相关性回归方程为Y=-60．98＋0．28X1＋3．90x2＋2．29X3。     

Habitat heterogeneity and life-history traits influence presettlement distributions of early-successional tree species in a late-successional, hemlock-hardwood landscape

In landscapes dominated by late-successional plant communities, early-successional species may lead a tenuous existence, persisting only as fugitives or relying on refuges in marginal habitats to provide a persistent seed source. The objective of this study was to relate fine-scale distributions of early-successional tree species in hemlock-hardwood forests of northern Wisconsin, USA to potential landscape persistence strategies. A special emphasis was placed on eastern white pine (Pinus strobus), a restoration priority in the region. Witness tree data from nineteenth century US Public Land Survey records (encompassing 40,610?km² and 106,790 trees) were used with modern environmental data to relate species distributions to habitat characteristics. Early-successional tree species had strong positive associations with marginal habitats such as inclusions of sandy soil and margins of lakes, wetlands, and rivers. Marginal habitats occupied ~44 % of the landscape, which may help account for the abundance of early-successional species in our study area relative to other hemlock-hardwood forests. Populations of early-successional species in marginal habitats could also have provided important seed sources for the upland mesic landscape matrix, as >70 % of the landscape was within 200?m of these habitats. The degree to which early-successional species were limited to marginal habitats largely followed predictions based on species life-history characteristics, except that white pine was more common than expected in upland mesic habitats. These findings illustrate the potential importance of landscape heterogeneity for persistence of early-successional species in late-successional forest landscapes and provide baseline information on habitat associations and landscape dynamics that will be useful in restoration efforts.     

A hypothesis to explain the relationship between low-temperature treatment,gibberellin activity,curd initiation and maturity of cauliflower

The effects of cold-treating young cauliflower plants (Brassica oleracea var. botrytis L.) of the cultivars ‘Lero’, ‘Lawyna’, ‘Novo’ and ‘Janavon’, on gibberellin activity and the spreads of curd initiation and maturity are described and discussed in relation to other similar work.Exposure of plants to 0°C for 15 days increased gibberellin activity in the apices of ‘Lero’ and ‘Lawyna’ plants. The spreads of curd initiation and maturity of ‘Lawyna’ were significantly reduced by cold-treatment at 0°C, but ‘Lero’ was not affected, possibly because plants had initiated too many leaves and were thus beyond the stage receptive to low-temperature treatment. This treatment had no effect on gibberellin activity nor on the spreads of curd initiation and maturity of ‘Novo’ or ‘Janavon’, probably because plants had not reached the sensitive stage when cold-treated.It is postulated that the phase of growth during which the curd-initiation period can be shortened by cold treatment is specific for each cultivar, and other data were used to confirm this. It seems likely that the receptive phase occurs at higher leaf-numbers with cultivars which take longer to initiate curds.     

Shifts in bat community structure related to evolved traits and features of human-altered landscapes

Population declines for many bat species are associated with rapid, human-induced ecosystem changes. In this context, the available species pool is determined in part by historical adaptation to the native ecosystem, but the resulting community structure may be determined principally by the ability of evolved traits to function in the novel context of a human-dominated ecosystem. To investigate the role of human disturbance as a determinant of bat communities, we surveyed assemblages and species occurrence rates in 27 agriculturally dominated landscapes exhibiting a gradient of human-induced forest fragmentation in Indiana, USA. We used multiple linear regression to explore the relationship of landscape environmental variables to species diversity. We then examined the relationship between community structure, evolved species traits and fragmentation conditions across a landscape using RLQ analysis. Overall, species diversity was positively related to the amount of forest and negatively correlated with amount of urban development in a landscape. We also observed a significant relationship between evolved species traits and landscape-level variables that is consistent with globally anticipated trends for bat species extinction risk. Our findings suggest that responses of bat species to human modification of ecosystems on the scale of a few kilometers could drive distributional dynamics at larger spatial and longer temporal scales.     

杨梅光合作用与生理生态因子的关系

采用LI—6400光合作用仪测定了东魁杨梅成熟期(6月下旬)叶片的净光合速率(Pn)以及气孔导度(Gs)、蒸腾速率(Tr)、光合有效辐射(PAR)、叶片温度(Tl)、空气相对湿度(RH)等生理生态因子的日变化,运用数理统计方法分析了Pn与各因子的相关关系。结果表明,东魁杨梅成熟期Pn日变化为双峰型曲线,存在"午休"现象;Pn与Gs和Tr均存在显著的二次曲线关系,与PAR有双曲线关系,与Tl有S型曲线关系,与RH有二次曲线关系。杨梅光合作用与各生理生态因子的关系密切,可为探讨杨梅合理栽培和区域选择提供一定的科学依据。     

Utility of landscape mosaics and boundaries in forest conservation decision making in the Atlantic Forest of Brazil

We evaluated changes in the Atlantic Forest landscape over the last 40 years based on changes in boundaries and mosaics, including the hypothetical landscape resulting from the application of Brazilian laws for forest protection. Mosaics were identified as sets of land-use patches with a similar pattern of boundaries. Landscapes of different years, therefore, can be distinguished by differences in mosaics. We developed a technique to identify boundaries between patches from land-use maps using ArcGis^® and to build the patch x boundary matrix required for mosaic identification by means of a factorial and cluster analysis. The mosaics were characterized by some key uses as well as by their boundaries with other land uses. The mosaics were scored for forest conservation according to five issues: landscape permeability, cover, availability, quality, and fragmentation of forest. The values were based on land use and boundary patterns. Although Brazilian laws regarding forest protection have promoted conservation and the hypothetical legal landscape has presented the highest forest habitat availability, this expansion perpetuates a boundary pattern that complicates conservation and management, thus increasing the pressure on forest patches and favoring the further fragmentation of protected forest patches. These conclusions cannot be reached by simply recording changes in land uses.     

Relationship between mutated k-ras and biological behavior of colorectal cancer

AIM: To investigate mutations of oncogene k-ras in colorectal cancer tissues and the relationship between mutations of k-ras and biological behavior of colorectal carcinoma. METHODS: The specimens of 123 patients with colorectal cancer were collected. Real-time fluorescence quantitative PCR were performed to detect k-ras mutations at codon 12 and codon 13 of exon 1, and the results were analyzed with the corresponding clinical pathological data. RESULTS: Among 123 colorectal cancer cases, point mutations were detected in 53 cases (40.8%), point mutations at codon 12 were found in 42 (34.1%) cases, and 11(8.9%) cases at codon 13. No closely relationship between mutations of k-ras and tumor size, location, invasive depth and differentiation extent was observed. The rate of k-ras mutation in the cases with more invaded lymph nodes was higher than that in the cases without invaded lymph nodes (P<0.05), and the rate of k-ras gene mutation in the cases with hepatic metastases was higher than that in no hepatic metastases (P<0.05). The rate of k-ras gene mutation was higher in TNM staging Ⅲ/Ⅳ than that in Ⅰ/Ⅱ(P<0.05). CONCLUSION: Mutation of oncogene k-ras plays an important role in the carcinogenesis and development of colorectal cancer, and it is closely associated with invaded lymph notes and hepatic metastases, suggesting that mutation of k-ras indicates a poor prognosis.     

Movement behavior in response to landscape structure: the role of functional grain

Landscape structure can influence the fine-scale movement behavior of dispersing animals, which ultimately may influence ecological patterns and processes at broader scales. Functional grain refers to the finest scale at which an organism responds to spatial heterogeneity among patches and extends to the limits of its perceptual range. To determine the functional grain of a model insect, red flour beetle (Tribolium castaneum), we examined its movement behavior in response to experimental flour landscapes. Landscape structure was varied by manipulating habitat abundance (0%, 10%, 30%, and 100%) and grain size of patches (fine-2 × 2 cm, intermediate-5 × 5 cm, and coarse-10 × 10 cm) in 50 × 50 cm landscapes. Pathway metrics indicated that beetles used a similar proportion of all landscape types. Several pathway metrics indicated a graded response from the fine to the coarse grain landscape. Lacunarity analysis of beetle pathways indicated a non-linear change in space use between the fine and intermediate landscapes and the coarse-grained landscape. Beetles moved more slowly and tortuously (with many turns), and remained longer in both the overall landscape and individual patches, in fine-grained compared to coarse-grained landscapes. Our research demonstrates how detailed examination of movement pathways and measures of lacunarity can be useful in determining functional grain. Spatially explicit, organism-centered studies focusing on behavioral responses to different habitat configurations can serve as an important first step to identify behavioral rules of movement that may ultimately lead to more accurate predictions of space use in landscapes.     

Interaction between human augmenter of liver regeneration and Na+-K+-ATPase in vitro

AIM: To check the physical interaction between GST- Na+-K+-ATPase domain and recombinant human augmenter of liver regeneration (rhALR) by GST pull down assay. METHODS: With PCR and genetic recombinant techniques, the coding region of β subunit of Na+-K+-ATPase was cloned into expressing plasmid pGEX-4T and identified by endonuclease digestion and sequencing methods. Under the inducing of 0.1 mmol/L IPTG, the fusion protein GST- Na+-K+-ATPase domain was highly expressed by E.coli DH-5α. After hypersound quassating, the GST- Na+-K+-ATPase domain was purified by glutathione agarose beads and the physical interaction with rhALR was checked by GST pull down assay. RESULTS: Analysis by SDS-PAGE showed the rhALRs of monomer and dimmer in GST- Na+-K+-ATPase domain lane. The Western blotting of the GST-pull down assay showed the same results as well. CONCLUSION: The Na+-K+-ATPase domain is associated with rhALR specifically in vitro.     

部分梨砧木的叶片组织结构与抗旱性的关系

为了评价西南喀斯特山区常用梨砧木的抗旱力强弱,了解其叶片组织解剖结构和保水力参数与抗旱性的关系,以川梨(Pyrus pashia Buch.-Ham.)、滇梨(P.pseudopa shia Yu)、砂梨(P.pyrifolia Nakai)和杜梨(P.betulaefolia Bge.)为材料,采用测定旱害指数的方法鉴定其抗旱力强弱,分析几种梨砧木叶片组织解剖结构和保水力参数与抗旱性的关系。结果表明,供试梨砧木的实际抗旱力强弱顺序为杜梨>川梨和滇梨>砂梨。梨砧木叶片栅栏组织与海绵组织的厚度比、叶肉组织结构紧密度(CTR)和水分临界饱和亏的大小,与砧木种间的旱害指数呈极显著的负相关,与抗旱性呈极显著的正相关;叶肉组织结构疏松度(SR)和失水速率的大小,与旱害指数呈极显著的正相关,与抗旱性呈极显著的负相关。杜梨的抗旱力极强,川梨和滇梨抗旱力强,砂梨的抗旱力中等。用叶片组织解剖结构参数指标鉴定梨砧木抗旱性可靠性较强,用叶片失水速率和水分临界饱和亏等指标鉴定梨砧木抗旱性与实际抗旱性具有较高的吻合度。     

梨树对白粉病抗性与叶片结构的关系

[目的]明确梨树对白粉病的抗性与叶片结构的关系.[方法]2018-2020年连续调查8个梨树品种田间白粉病的发生程度,室内观测各品种的叶片气孔和茸毛密度、蜡质含量、比叶重及横切面组织结构特征.[结果]不同梨树品种对白粉病的抗性水平存在明显差异;不同抗性品种间叶片的气孔密度、比叶重差异不显著,与品种抗病性无关;不同抗感品...     

A comparative analysis of the genetic diversity between inbred lines of Zinnia elegans using morphological traits and RAPD and ISSR markers

Genetic diversity within Zinnia elegans is key to the genetic improvement of this important ornamental species. Here, morphological traits and RAPD and ISSR molecular markers were used to assess levels of polymorphism across 20 inbred lines. Thirty-four morphological traits were scored and also 147 RAPD marker-fragments, as amplified by 12 arbitrary primers, and 128 ISSR marker-fragments as generated by 9 primers. The number of polymorphic loci, the percentage of polymorphic loci, Shannon's Information index (I) and the effective number of alleles (Ne) were calculated from the RAPD data as 100, 68.03%, 0.3559 and 1.4169, respectively. From the ISSR data, these respective statistics were calculated as 97, 76.38%, 0.4013 and 1.4728. Thus, ISSR markers were considered slightly superior to RAPD markers for assessing genetic diversity between the accessions; however, Mantel's test indicated significant correlation (R = 0.733) of the RAPD and ISSR results. By contrast, the morphological matrix showed low correlation with both RAPD and ISSR data matrices (R = 0.3814 and 0.3765, respectively). Cluster analysis showed that groupings of the accessions according to all three methods correlated well with their geographic region of origin, but flower color was not strongly associated with the genetic classification of these inbred lines of Z. elegans.