Occupancy pattern of a long-horned beetle in a variegated forest landscape: linkages between tree quality and forest cover across spatial scales

Context

Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.

Objectives

We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.

Methods

We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).

Results

Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.

Conclusions

M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.

     

QTL mapping and analysis of epistatic interactions for grain yield and yield-related traits in <Emphasis Type="Italic">Triticum turgidum</Emphasis> L. var. <Emphasis Type="Italic">durum</Emphasis>

A quantitative trait loci (QTL) analysis of grain yield and yield-related traits was performed on 93 durum wheat recombinant inbred lines derived from the cross UC1113 × Kofa. The mapping population and parental lines were analyzed considering 19 traits assessed in different Argentine environments, namely grain yield, heading date, flowering time, plant height, biomass per plant, and spikelet number per ear, among others. A total of 224 QTL with logarithm of odds ratio (LOD) ≥ 3 and 47 additional QTL with LOD > 2.0 were detected. These QTL were clustered in 35 regions with overlapping QTL, and 12 genomic regions were associated with only one phenotypic trait. The regions with the highest number of multi-trait and stable QTL were 3BS.1, 3BS.2, 2BS.1, 1BL.1, 3AL.1, 1AS, and 4AL.3. The effects of epistatic QTL and QTL × environment interactions were also analyzed. QTL putatively located at major gene loci (Rht, Vrn, Eps, and Ppd) as well as additional major/minor QTL involved in the complex genetic basis of yield-related traits expressed in Argentine environments were identified. Interestingly, the 3AL.1 region was found to increase yield without altering grain quality or crop phenology.     

Addition of Sodium Stearoyl Lactylate to Corn and Sorghum Starch Extrudates Enhances the Performance of Pregelatinized Beer Adjuncts

Double mashing for wort production is a time‐consuming process that can be reduced if pregelatinized adjuncts are used. Optimal extruding conditions were determined to obtain brewing adjuncts from corn and sorghum starch. For corn starch extrusion, a Box–Behnken design was devised in which moisture, screw speed, temperature of the barrel, and concentrations of sodium stearoyl lactylate (SSL) were varied, and sorghum starch was extruded according to a 2³ model in which the modified variables were moisture, SSL concentration, and temperature. The aim was to maximize starch damage and minimize resistant starch and final viscosity as determined with a Rapid Visco Analyzer. The treatments that satisfied these requirements were mashed, and wort extract yield was determined. Glucose, maltose, and maltotriose concentrations in the resulting worts were determined by HPLC with a refractive index detector. Feedstock tempering and SSL content were the most important factors affecting the response; for corn starch, treatments with lower moisture (20%) and middle levels of SSL (0.5%) or with high levels of both moisture (40%) and SSL (1%) produced the most desirable samples for mashing, whereas for sorghum starch the best treatment was tempering to 20% moisture and containing middle levels of SSL (0.5%). No statistical differences were found between these experimental treatments and the control.     

The role of feral mammals on wildlife infectious disease prevalence in two nature reserves within Mexico City limits.

Wild and feral medium-sized mammals were live trapped at two natural protected areas within the Mexico City limits to determine antibody prevalence for the most common infectious diseases (rabies, toxoplasmosis, and canine parvovirus) in dogs and cats. Mammals were trapped during the dry (March-April) and rainy seasons (July-August) of 1996 and 1997. A total of 68 individuals were captured, representing 8 species: opossums (Didelphis virginiana), ringtails (Bassariscus astutus), spotted skunks (Spilogale gracilis), weasels (Mustela frenata), rock squirrels (Spermophilus variegatus), Mexican gray squirrels (Sciurus aureogaster), feral cats (Felis catus), and feral dogs (Canis familiaris). There was marked seroprevalence for parvovirus (86.6%) and lower seroprevalences for both toxoplasma (23.9%) and rabies (17.9%). There were no significant prevalence differences among mammals in both protected areas, which were of contrasting size and isolation (i.e., small and isolated versus large and nonisolated). We suggest that high seroprevalence of these three infectious agents in wild mammals is a result of the high densities of feral dogs and cats in the two areas sampled. Feral dogs are able to maintain the infectious agents in these localities regardless of the protected area size and isolation. However, the native mammals of the small and isolated reserve are more vulnerable to infectious diseases because of small population size and genetic bottlenecks. Our results indicate that natural areas in and around Mexico City are a refugium for latent infectious agents, several of which are zoonotic. These findings suggest that conservation measures, such as eradication of feral mammals and vaccination programs, in the protected areas and surrounding areas could be beneficial.     

Effect of single Quercus ilex trees upon spatial and seasonal changes in soil water content in dehesas of central western Spain

The spatial and temporal evolution of soil water content (θ) in Quercus ilex dehesas has been investigated to determine how trees modify the soil water dynamics and the nature of tree-grass interactions in terms of soil water use in these ecosystems. Soil physical parameters and θ were measured at different distances from the tree trunk (2–30 m) in the upper 300 cm of soil. θ was measured monthly by TDR during 2002–2005. Tree water potential was determined during the summers of 2004 and 2005. At deeper soil layers, mean θ values were higher beyond than beneath tree canopy during dry periods. θ depletion beyond tree canopy continued even in summer, when herbaceous plants dried up, suggesting that trees uptake water from the whole inter-tree space. Results have shown a high dependence of trees on deep water reserves throughout late spring and summer, which helps to avoid competition for water with herbaceous vegetation.     

Growth and development of the arborescent cactus Stenocereus queretaroensis in a subtropical semiarid environment,including effects of gibberellic acid

In Stenocereus queretaroensis (Weber) Buxbaum, an arborescent cactus cultivated in Jalisco, Mexico, for its fruits but studied here in wild populations, stem extension occurred in the autumn at the beginning of the dry season, flowering and fruiting occurred in the spring at the end of the dry season, and new roots grew in the summer during the wet season. The asynchrony of vegetative and reproductive growth reduces competitive sink effects, which may be advantageous for wild populations growing in infertile rocky soils. Seasonal patterns of sugars in the roots and especially the stems of S. queretaroensis were closely related to the main phenological stages, becoming lower in concentration during periods of major stem extension. Cessation of stem extension occurred in 100-year-old plants for which injection of GA(3) reinitiated such growth. Isolated chlorenchyma cylinders had maximum extension in a bathing solution containing 0.1 &mgr;M gibberellic acid.     

Effect of different levels of dietary sweet orange (Citrus sinensis) peel extract on humoral immune system responses in broiler chickens

This experiment was conducted to evaluate the effects of different levels of sweet orange (Citrus sinensis) peel extract (SOPE) on humoral immune system responses in broiler chickens. Three hundred 1‐day broilers (Ross‐308) were randomly allocated to treatments varying in supplemental SOPE added in the drinking water. The experimental groups consisted of three treatments fed for 42 days as follows: a control treatment without feed extract, a treatment containing 1000 ppm of SOPE and a treatment containing 1250 ppm of SOPE. All treatments were isocaloric and isonitrogenous. Broilers were vaccinated with Newcastle disease virus (NDV), avian influenza (AI), infectious bursal disease (IBD) and infectious bronchitis virus (IBV) vaccines. Antibody titer response to sheep red blood cells (SRBC) was higher in the group fed 1250 ppm of SOPE (P < 0.05) as well as for immunoglobulin G (IgG) and IgM. Similarly, antibody titer responses to all vaccines were constantly elevated (P < 0.05) by SOPE enrichment in a dose‐dependent manner. Relative weights of spleen and bursa of Fabricius were unaffected by treatments. Dietary SOPE supplementation may improve the immune response and diseases resistance, indicating that it can constitute a useful additive in broiler feeding. Thus, supplying SOPE in rations may help to improve relative immune response in broiler chickens.     

Detection of Invasive Borrelia burgdorferi Strains in North‐Eastern Piedmont,Italy

Following reports of human cases of Lyme borreliosis from the Ossola Valley, a mountainous area of Piemonte, north‐western Italy, the abundance and altitudinal distribution of ticks, and infection of these vectors with Borrelia burgdorferi sensu lato were evaluated. A total of 1662 host‐seeking Ixodes ricinus were collected by dragging from April to September 2011 at locations between 400 and 1450 m above sea level. Additional 104 I. ricinus were collected from 35 hunted wild animals (4 chamois, 8 roe deer, 23 red deer). Tick density, expressed as the number of ticks per 100 m², resulted highly variable among different areas, ranging from 0 to 105 larvae and from 0 to 22 nymphs. A sample of 352 ticks (327 from dragging and 25 from wild animals) was screened by a PCR assay targeting a fragment of the 16S rRNA gene of B. burgdorferi s.l. Positive samples were confirmed with a PCR assay specific for the 5S‐23S rRNA intergenic spacer region and sequenced. Four genospecies were found: B. afzelii (prevalence 4.0%), B. lusitaniae (4.0%), B. garinii (1.5%) and B. valaisiana (0.3%). Phylogenetic analysis based on the ospC gene showed that most of the Borrelia strains from pathogenic genospecies had the potential for human infection and for invasion of secondary body sites.     

Helminth parasites of freshwater fishes from Cuatro Ciénegas,Coahuila, in the Chihuahuan Desert of Mexico: inventory and biogeographical implications

As part of an ongoing inventory of the helminth parasites of freshwater fishes in Mexico, 570 individual fish were collected between Apr 2008 and Oct 2011 in 26 localities along the Cuatro Ciénegas region in Coahuila State, northern Mexico. Seventeen species of hosts, mostly corresponding to Nearctic freshwater elements, were studied. A total of 8324 individual worms were collected during this survey, representing 25 species of helminths, of which 9 were digeneans, 3 monogeneans, 3 acanthocephalans, 9 nematodes and 1 cestode. Most of the records in this checklist represent new host or locality records. The information provided in this checklist may be helpful for our understanding of the biodiversity and historical biogeography of this host–parasite system, because in the Cuatro Ciénegas region occur a Nearctic freshwater fish fauna, along with Neotropical and endemic elements, and from a biogeographical point of view, this may represent a transitional area.     

Chronosequence of Technosols at the Peña Colorada mine in Colima,Mexico: a short-term remediation alternative

Journal of Soils and Sediments - The objective of this study was to examine the pedogenetic evolution occurring in technic hard materials from an iron mine through the characterization of a...