Spatio-temporal variation in the demographic attributes of a generalist mesopredator

Human land-use practices have dramatically altered the composition and configuration of native habitats throughout many ecosystems. Within heterogeneous landscapes generalist predators often thrive, causing cascading effects on local biological communities, yet there are few data to suggest how attributes of fragmentation influence local population dynamics of these species. We monitored 25 raccoon (Procyon lotor) populations from 2004 to 2009 in a fragmented agricultural landscape to evaluate the influence of local and landscape habitat attributes on spatial and temporal variation in demography. Our results indicate that agricultural ecosystems support increased densities of raccoons relative to many other rural landscapes, but that spatial and temporal variation in demography exists that is driven by non-agricultural habitat attributes rather than the availability of crops. At the landscape scale, both density and population stability were positively associated with the size and contiguity of forest patches, while at the local scale density was positively correlated with plant diversity and the density of tree cavities. In addition, populations occupying forest patches with greater levels of plant diversity and stable water resources exhibited less temporal variability than populations with limited plant species complexity or water availability. The proportion of populations comprised of females was most strongly influenced by the availability of tree cavities and soft mast. Despite the abundance of mesopredators in heterogeneous landscapes, our results indicate that all patches do not contribute equally to the regional abundance and persistence of these species. Thus, a clear understanding of how landscape attributes contribute to variation in demography is critical to the optimization of management strategies.     

Landscape characteristics explain large-scale variation in demographic traits in forest grouse

The effects of landscape composition on species and populations have become increasingly important due to large and rapid habitat changes worldwide. In particular, concern is raised for several forest-dwelling species such as capercaillie and black grouse, because their habitats are continuously changing and deteriorating from human development. Conservation of these species is linked to sustainable forest management that seeks to benefit multiple species, which demands knowledge about demographic rates in relation to forest composition and structure. We related the spatial variation in adult density and chick production of capercaillie and black grouse to landscape characteristics from 13 areas within the boreal forest of Norway. Linear mixed effects models showed that black grouse and capercaillie had similar associations to landscape characteristics. Adult density of both species was positively related to the proportion of old forest (>80 years), but only if the area had large proportions of mid to high productive forests. Chick production was negatively related to the proportion of old forest, but positively to habitat diversity and more so for black grouse compared to capercaillie. However, the result for chick production suggest that other forest types also are important, and that forest grouse needs a variety of habitats during their life history stages. Management that seeks to simultaneously conserve populations of black grouse and capercaillie needs to ensure a matrix of various forest types. A special focus must be on the critical life history of local populations to successfully preserve viable populations, for black grouse and capercaillie this implies protection of old and mid to high productive forest while keeping a heterogeneous landscape.     

Spatial variation in forage nutrient concentrations and the distribution of Serengeti grazing ungulates

Resident grazing ungulates in the Serengeti National Park, Tanzania, are conspicuously patchy in their distribution among regions of the Park. Linear programming models that maximize nitrogen (N) consumption by foraging ungulates in Serengeti regions having high and low resident animal densities were compared using forage ingestion rate and twelve nutritional requirements as simultaneously imposed constraints on forage choice. Model results indicate that (1) growing season N or crude protein is not limiting in either region although greater N ingestion is possible within the eastern corridor under other nutritional constraints, (2) grazing ungulates in the eastern corridor region occur in greater density and are capable of balancing dietary requirements solely from forage while simultaneously consuming more protein than ungulates in the northeast region, and (3) rarer landscape elements are most capable of providing ungulate dietary requirements in both the northeast and eastern corridor. These results provide a nutritional basis to understand patchy spatial distributions of grazers within Serengeti regions and landscapes, and provide a partial test of the hypothesis that large generalist herbivores should graze rare forages more frequently. The ability of uncommon landscape elements to support ungulate grazing over the growing season is supported by previous ecosystem studies that demonstrate the capability of grass forages for compensatory growth and the ability of grazing to stimulate rapid nutrient recycling.     

Spatial versus temporal variation in precipitation in a semiarid ecosystem

Spatial and temporal variations in precipitation are central features of semiarid ecosystems, influencing patterns of plant productivity and the distribution of native fauna. Although temporal variation in precipitation has been studied extensively, far less is known about the spatial scale and pattern of precipitation variability in semiarid regions. I used long-term precipitation records to examine spatial variation across the 63 km² Central Plains Experimental Range in northeastern Colorado, and across the 117,000 km² region of shortgrass steppe in eastern Colorado. Relative to temporal variation, spatial variation was low at scales <10 km, increased linearly across scales of 40–120 km, and was nearly equal in magnitude to temporal variation across distances of 120–160 km. Although I hypothesized that most spatial variation would be generated by early-summer convective thunderstorms in June, I found that the magnitude and spatial pattern of variation was similar for precipitation received in June compared to cumulative precipitation received during the full growing season. The degree of spatial autocorrelation in precipitation across all distances that I evaluated was similar for drought, dry, above-average and wet years. Across distances of 10–120 km, spatial variation within a single growing season was approximately two times greater than spatial variation in long-term mean growing-season precipitation, indicating spatial shifting in the locations of patches of high and low precipitation over multiple years. Overall, these findings suggest spatial variation at scales of 10–160 km may have been an important factor influencing vegetation patterns and migratory fauna of the shortgrass steppe, and have implications for livestock producers and future assessments of climate change.     

The future demographic niche of a declining grassland bird fails to shift poleward in response to climate change

Context

Temperate grasslands and their dependent species are exposed to high variability in weather and climate due to the lack of natural buffers such as forests. Grassland birds are particularly vulnerable to this variability, yet have failed to shift poleward in response to recent climate change like other bird species in North America. However, there have been few studies examining the effect of weather on grassland bird demography and consequent influence of climate change on population persistence and distributional shifts.

Objectives

The goal of this study was to estimate the vulnerability of Henslow’s Sparrow (Ammodramus henslowii), an obligate grassland bird that has been declining throughout much of its range, to past and future climatic variability.

Methods

We conducted a demographic meta-analysis from published studies and quantified the relationship between nest success rates and variability in breeding season climate. We projected the climate-demography relationships spatially, throughout the breeding range, and temporally, from 1981 to 2050. These projections were used to evaluate population dynamics by implementing a spatially explicit population model.

Results

We uncovered a climate-demography linkage for Henslow’s Sparrow with summer precipitation, and to a lesser degree, temperature positively affecting nest success. We found that future climatic conditions—primarily changes in precipitation—will likely contribute to reduced population persistence and a southwestward range contraction.

Conclusions

Future distributional shifts in response to climate change may not always be poleward and assessing projected changes in precipitation is critical for grassland bird conservation and climate change adaptation.

     

Spatial variation in glasshouse rose flower production in relation to solar radiation

Analysis of yield of rose flowers grown in glasshouses during the winter shows that a very significant difference exists in the total number of flowers along the east—west axis, with a centre minimum. The difference between east and centre was highest (almost 50 % difference in total number of flowers and 30 % difference in number of marketable flowers) in the first part of the season, when insolation was lowest. The variation in the north—south axis was less pronounced, but still highly significant (15 % during more than half of the season). The ratio of the number of marketable flowers to the total number of flowers varied only along the east—west axis, with the highest percentage at the centre. No significant differences in ratio were found in the north—south axis. The variations along the east—west axis and the north—south axis in number of flowers were related to variation in solar radiation within the glasshouses.     

The potential role of neurotrophic factor in the pathogenesis and therapy of Parkinson's disease

Parkinson’s disease is characterized by degeneration and dysfunction of dopaminergic neurons in the mid-brain substantia nigra, neurons that project to the caudate putamen. The clinical symptoms are caused by the loss of dopamine and the consequent dysfunction of the nigrostriatal pathway. Neurotrophic factors that may prevent nigrostriatal degeneration by improving the function of remaining dopaminergic neurons has the potential to be a useful therapy for Parkinson’s disease. Neurotrophic factors and their specific receptors could play an important role in the progress of Parkinson’s disease. The neuroprotective effects of neurotrophic factors GDNF, BDNF, IL-6 on dopaminergic neurons in vivo and in vitro, and the potential therapeutic use in treating Parkinson’s disease were discussed in this paper.     

Expression and potential role of chaperonin 60 in experimental acute pancreatitis

AIM:To explore the expression and potential impacts of chaperonin 60 (Cpn60) in the hepatic and pancreatic tissues from animals endured experimental acute pancreatitis (AP) with various severities. METHODS:Induction of mild acute pancreatitis (MAP) in mice was made by intraperitoneal injection of caerulein, and sodium deoxycholate was used by injection through pancreato-biliary duct backward to induce severe acute pancreatitis (SAP) in rats. The liver and pancreas from sacrificed animals at 1 h, 5 h and 10 h time points post-induction of AP were harvested for pathological examination and observing the dynamic change of Cpn60 expression with techniques of immunoprecipitation (IP) and Western blotting. RESULTS:In the MAP and SAP models, pancreatic tissues showed swollen or hemorrhagic necrotic changes, respectively. The characteristic differences of Cpn60 expression were also observed. The Cpn60 protein was expressed as two distinctive bands in pancreatic and hepatic tissues, and relative densities of the two bands varied differently at these time points in both AP models. CONCLUSION:The results suggest that not only the quantitative, but also, probably, qualitative abnormalities of Cpn60 expression in AP exist. These abnormalities may play important roles in the pathogenesis and development of acute pancreatitis.     

Plant and animal diversity in a region of the Southern Alps: the role of environmental and spatial processes

Different organisms respond to landscape configuration and spatial structure in different terms and across different spatial scales. Here, regression models with variation partitioning were applied to determine relative influence of the three groups of variables (climate, land use and environmental heterogeneity) and spatial structure variables on plant, bird, orthopteran and butterfly species richness in a region of the Southern Alps, ranging in elevation from the sea level to 2,780 m. Grassland and forest cover were positively correlated with species richness in both taxonomic groups, whilst species richness decreased with increasing urban elements and arable land. The variation was mainly explained by the shared component between the three groups in plants and between landscape and environmental heterogeneity in birds. The variation was related to independent land use effect in insects. The distribution in species richness was spatially structured for plants, birds and orthopterans, whilst in butterflies, no spatial structure was detected. Plant richness was associated with linear trend variation and broad-scale spatial structure in the northern part of the region, whilst bird richness with broad-scale variation which occurs on the external Alpine ridge. Orthopteran diversity was strongly related to fine-scale spatial structure, generated by dynamic processes or by unmeasured spatially structured abiotic factors. Although the study was carried out in relatively small area, the four taxonomic groups seem to respond to biodiversity drivers in a surprisingly different way. This has considerable implications for conservation planning as it restricts the usefulness of simple indicators in prioritizing areas for conservation purposes.     

Expression of cathepsin B and cystatin C and its potential role in diabetic rats

AIM: To observe the expressions of cathepsin B (CB) and cystatin C (CC) in different stage of diabetic rats and to investigates their potential roles.METHODS: Sixty rats were divided into diabetes mellitus group induced by intravenous injection of streptozotocin (55 mg/kg) and normal group injected with citrate buffer. Ten rats were sacrificed respectively at the end of fourth week, eighth week and sixteenth week in both groups. 24 h urine excretion was collected in rats before sacrifice. The blood and the kidney were also collected. The mRNA and protein expressions of CB and CC in kidney were detected by real time PCR and immunohistochemical staining, respectively.RESULTS: At the end of eighth week, the expression of Ccr, 24 h urinary protein excretion, CB, CC in diabetic rats increased significantly, compared to the results at the fourth week (P<0.01 or P<0.05). With the aggravation of diabetic nephropathy, the expressions of CC, colⅣ, FN and 24 h urinary protein excretion were up-regulated significantly (P<0.01 or P<0.05). The expression of CB in diabetic rats was up-regulated at eighth week significantly (P<0.01), whereas, at the end of sixteenth week it was down-regulated significantly (P<0.01). The 24 h urinary protein excretion, the expressions of colⅣ at protein and mRNA levels and FN were negatively correlated with CB (P<0.01).CONCLUSION: The unbalance of CB and CC exists in diabetic nephropathy renal tissue, which is likely to lead to the accumulation of extracellular matrix.     

The potential role of staphylococcal enterotoxin B in the early intestinal injury in postburn Staphylococcus aureus sepsis

AIM: To investigate the role of staphylococcal enterotoxin B (SEB) in early intestinal injury in scald rats with Staphylococcus aureus sepsis. METHODS: 86 male Wistar rats were randomly divided into four groups as folows: normal controls (n=10), scald control group(n=10), postburn sepsis group (n=50) and SEB monoclonal antibody (MAb) treatment group (n=16). Plasma samples were collected to determine SEB, endotoxin, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). RESULTS: After scald injury followed by Staphylococcus aureus challenge, the levels of SEB, TNF-α and IFN-γ in plasma were significantly higher than those of normal controls, peaking at 2-6 h (P<0.05 or P<0.01), while the intestinal diamine oxidase (DAO) activity declined constantly (P<0.05). It was shown that plasma SEB levels were significant negatively correlated with intestinal DAO activity (r=-0.4398, P=0.0170), and SEB MAb pretreatment could ameliorate the intestinal injury to certain extent. Moreover, Staphylococcus aureus challenge could increase the endotoxin levels in plasma and various tissues, which were attenuated by SEB MAb pretreatment. CONCLUSION: In postburn sepsis, SEB might be involved in the development of intestinal barrier dysfunction, which in turn resulting in gut-derived endotoxin translocation and aggravating the pathophysiologic changes caused by Staphylococcus aureus challenge.     

Pollination management for controlled hybridization of white yam

Pollination and fertilization success in white yam, Dioscorea rotundata Poir., depend on knowledge and good management of factors influencing the availability of open male flowers from which good pollen can be collected for effective use in pollinations of genetically compatible female plants under non-xeric conditions. In vitro germination of pollen from numerous genotypes demonstrated varied viability (0.3–85.0%). However, pollen from bisexual flowers on monoecious plants was inferior to pollen from unisexual flowers from dioecious plants. Natural pollination by thrips is inefficient, such that populations with higher ratios of male to female plants set more fruits. To improve fruit set, hand pollinations should be made with pollen from diverse genotypes, early in the flowering period when net water balance is positive. In crossing-blocks, male plants should be closely interpositioned with female plants to reduce pollination distance, thereby improving pollination and fruit set.     

果树远缘杂交育种研究进展

远缘杂交是指种或属间及亲缘关系更远的分类单位间进行的杂交,它是创造果树新种质的重要途径。简要列举了果树远缘杂交育种取得的主要成就,阐述了远缘杂交不亲和和育性障碍的若干表现与机制。目前克服杂交障碍的途径有:蕾期授粉、混合花粉、重复授粉、亲本选择、特殊处理、胚抢救和染色体加倍等。杂交后代遗传变异分为3种类型:综合性状类型、亲本性状类型和新物种类型。杂交后代的早期鉴定方法有形态鉴定、染色体鉴定、同工酶鉴定和分子鉴定。果树远缘杂交育种虽然困难很多,但前景非常广阔,今后的重点是深入研究远缘杂交不亲和和育性障碍的机理和有效的克服途径,并借助分子标记技术对杂种进行早期鉴定以及对复杂遗传规律进行深入研究。     

In situ hybridization for the detection of rust fungi in paraffin embedded plant tissue sections

Background

Rust fungi are obligate pathogens with multiple life stages often including different spore types and multiple plant hosts. While individual rust pathogens are often associated with specific plants, a wide range of plant species are infected with rust fungi. To study the interactions between these important pathogenic fungi and their host plants, one must be able to differentiate fungal tissue from plant tissue. This can be accomplished using the In situ hybridization (ISH) protocol described here.

Results

To validate reproducibility using the ISH protocol, samples of Chrysanthemum × morifolium infected with Puccinia horiana, Gladiolus × hortulanus infected with Uromyces transversalis and Glycine max infected with Phakopsora pachyrhizi were tested alongside uninfected leaf tissue samples. The results of these tests show that this technique clearly distinguishes between rust pathogens and their respective host plant tissues.

Conclusions

This ISH protocol is applicable to rust fungi and potentially other plant pathogenic fungi as well. It has been shown here that this protocol can be applied to pathogens from different genera of rust fungi with no background staining of plant tissue. We encourage the use of this protocol for the study of plant pathogenic fungi in paraffin embedded sections of host plant tissue.

     

Precipitation,fire and demographic bottleneck dynamics in Serengeti tree populations

Tree size distributions are the outcome of demographic processes and disturbance events, and size distribution analysis provides a useful tool for understanding pattern and process in tree population dynamics. Demographic bottleneck mechanisms such as fire “traps” are important for driving tree cover dynamics in savanna systems, and bottlenecks might be expected to be revealed by bimodal size distributions in savanna tree communities. We tested the relative fit of monotonic and bimodal Weibull distributions to tree height distributions across 36 0.1-ha plots over 4 years in Serengeti National Park, Tanzania, using a Bayesian analysis. The plots were subjected to two fire treatments and spanned a mean annual rainfall gradient ranging from 600 to 900 mm year^?1. We found that Serengeti trees are highly bimodal in their height distributions, with a pronounced gap in the 1–3 m height range, suggesting that demographic bottlenecks are a pervasive feature of this system. We also found that pre- and post-bottleneck tree densities are increasing and declining over time, respectively. Pre-bottleneck density declined with fire and increased with mean annual precipitation, and exhibited a rainfall by fire interaction, with negative fire effects becoming more important at the wet extreme of our rainfall gradient. Overall, despite the negative effect of fire on pre-bottleneck trees, the density of the latter is increasing over time, suggesting that although recruitment into larger size classes has been tightly constrained in the past, there is mixed support for a role of fire in maintaining this pattern under current burning regimes.     

Genetic and environmental variation for corolla traits in Portulaca grandiflora

A commercial seed lot of Portulaca grandiflora was sampled and the variation for several flower traits was analysed. A genotypic component of variance was estimated for the traits petal length, petal width, and petal number. The heritability for petal number was high (64 · 3), for petal width was intermediate (31 · 3), and for petal length was low (12–3). The environmental variance was partitioned into three components, but more than 90% of it was unaccountable. A significant positive correlation between petal length and petal width was found. A covariance analysis was used to test for genetic variance for petal length and petal width after the effects of covariance had been removed. No relationship was found between total corolla area and flower production. Thus, selection for larger flowers is not expected to reduce the number of flowers produced. Selection responses are predicted for different selection differentials and the assumptions are discussed. The results suggest that selection for increased petal number will be very effective.     

桃、李种间远缘杂交亲和性研究

利用荧光显微镜和石蜡切片研究桃、李种间远缘杂交的亲和性。结果表明,以桃为母本,李为父本进行杂交,其受精率和结实率均为3%左右。授粉后李的花粉粒在桃的柱头上萌发基本正常,花粉管在进入花柱中部以前生长正常,之后生长缓慢发育受阻,大多数花粉管不能进入子房,致使无法受精,这是桃、李杂交不亲和、结实率低的主要原因。     

Compensating for the loss of future tree values in the model of Fuzzy knowledge units

When working with any application domain, it is necessary to grasp and represent the knowledge from this application domain into a suitable form. There is naturally a significant difference between the knowledge gained from natural knowledge, estimation and experience, and the knowledge gained through exact measurement, but it is often necessary to use estimates based on experience in decision-making processes. This is especially important if this representation is to be used in decision support systems using e.g. artificial intelligence (AI) and machine learning (ML). In this paper, we therefore describe a model for valuing solitary trees that allows the use of vague evaluation of input parameters for the evaluation of trees based on fuzzy knowledge units. The creation of the model is based on the parametric method of the Nature Conservation Agency (NCA) and other methods such as CAVAT or FEM, from which the knowledge text is separated. Fuzzy knowledge units (FKU) or Knowledge units (KU) are created from this knowledge text. These FKU are trained according to data from the NCA method and optimized using the MATLAB Tune fuzzy inference system (TUNEFIS). The Adaptive neuro fuzzy inference system (ANFIS) was chosen as the best FKU model. These fuzzy knowledge units are arranged in a hierarchical model of valuing solitary trees, which is implemented in Simulink. The experimental study clearly shows that the proposed model is more detailed in some parameters than a crisp tree evaluation calculator or CAVAT calculator in excel and provides more precise results.