A GIS-based integrated approach predicts accurately post-fire Aleppo pine regeneration at regional scale

Context

This study investigates post-fire natural regeneration of Aleppo pine (Pinus halepensis) forests at Ilia region (Peloponnesus, Greece) following the catastrophic fire of 2007.

Aims

The objective of this study is the prediction of P. halepensis post-fire regeneration at a regional scale through an integrated geographic information systems (GIS) model as a basis for post-fire management plans.

Methods

The model was developed in three interconnected stages: (1) field data collection, (2) development of two prediction models (based on interpolation of field data and multi-criteria evaluation (MCE) that combined factors known to affect regeneration), and (3) combination of applied models using Bayesian statistics.

Results

Post-fire pine regeneration presented high variation among the studied plots. Redundancy analysis revealed the positive effect of fallen branches and a negative correlation with altitude. Both modeling approaches (geostatistical and MCE) predicted the post-fire pine regeneration with high accuracy. A very significant correlation (r?=?0.834, p?<?0.01) was found between the combined final model and the actual number of counted seedlings, illustrating that less than 10?% of the studied area corresponds to sites of very low post-fire pine regeneration.

Conclusions

The combination of GIS models increased the prediction success of different levels of pine regeneration. Low-altitude areas with low grass cover overlying tertiary deposits were proved the most suitable for pine regeneration, while stands developing on limestone proved least suitable. The proposed methodology provides management authorities with a sound tool to quickly assess Aleppo pine post-fire regeneration potential.     

Dust mite species in the households of mite-sensitive dogs with atopic dermatitis

Background – The presence of important house dust and storage mite species in the microenvironment of atopic dogs has not been thoroughly investigated. Objectives – To compare the presence and population of five dust mite species (Dermatophagoides farinae, Dermatophagoides pteronyssinus, Acarus siro, Tyrophagus putrescentiae and Lepidoglyphus destructor) among households with mite‐sensitive atopic dogs (Group A), households with clinically healthy dogs (Group B) and households without pets (Group C, n = 25) in Greece. Animals – Twenty mite‐sensitive atopic dogs and 20 clinically healthy dogs. Methods – Dust samples were collected with a vacuum cleaner from owners’ mattresses (all groups) and from dogs’ sleeping areas (Groups A and B) or living room couch (Group C), once every season of the year. Following dust flotation, mites were counted and identified. Results – Dermatophagoides farinae was the most prevalent (60, 40 and 64% in Groups A, B and C, respectively), followed by D. pteronyssinus (45, 35 and 48%, respectively), whereas the three storage mites were found in fewer households. No major differences could be found between Groups A and B or between households with (Groups A and B) and without dogs (Group C) regarding the presence or numbers of the five dust mite species. Conclusions and clinical importance – The presence and population of five common house dust and storage mite species does not differ among Greek households with mite‐sensitive atopic dogs, households with healthy dogs and households without pets.     

The relationship between the chemical composition of three essential oils and their insecticidal activity against Acanthoscelides obtectus (Say)

The chemical composition of the essential oils isolated from various parts of three Greek aromatic plants (Lavandula hybrida Rev, Rosmarinus officinalis L and Eucalyptus globulus Labill) collected at different seasons was determined by GC/MS analysis. The insecticidal action of these oils and of their main constituents on Acanthoscelides obtectus (Say) adults was evaluated and their LC50 values were estimated. All essential oils tested exhibited strong activity against A. obtectus adults, with varying LC50 values depending on insect sex and the composition of the essential oils. A correlation between total oxygenated monoterpenoid content and activity was observed, with oxygenated compounds exhibiting higher activity than hydrocarbons. Among the main constituents, only linalyl and terpinyl acetate were not active against A. obtectus, while all the others exhibited insecticidal activity against both male and female adults, with LC50 values ranging from 0.8 to 47.1 mg litre(-1) air. An attempt to correlate the insecticidal activity to the monoterpenoid's structure is presented, and the difference in sensitivity between male and female individuals is also explored.     

In-vitro susceptibility testing of Leptospira by a modified broth microdilution methods

In Germany, the application of antimicrobial agents represents the method of choice to control infections of food-producing animals by bacteria of the genus Leptospira. However, only few data are available on the susceptibility of Leptospira spp. against antimicrobial agents and the in vivo efficacy of antimicrobial agents. Based on a modified broth microdilution method, a standardised in-vitro susceptibility testing system for Leptospira spp. was established which also included quality control aspects. Considering the minimum inhibitory concentrations determined in this study in-vivo efficacy is expected for the following classes of antimicrobial agents: penicillins, cephalosporins, macrolides, lincosamides, fluoroquinolones, phenicols, and in part also for aminoglycosides and tetracyclines. Clinical aspects and bioavailability of the drugs in the target tissues have to be taken into account. Penicillins and aminoglycosides as commonly used inhibitory supplements in semen extender seem to be effective against leptospires.     

Risk analysis of pesticides applied to rice paddies using RICEWQ 1.6.2v and RIVWQ 2.02

Rice is commonly cultivated in Southern Europe in large river basins where the extensive use of herbicides may impact water quality at basin scale level. Consequently, pesticide risk assessment would be more relevant when considering a rice cultivation area as a whole. Accordingly, two watershed-scale scenarios were developed to represent the specific agronomic, water and pesticide management practices of rice cultivation in Greece. These scenarios were utilized for the parameterization of the rice water quality model (RICEWQ) 1.6.2v and the surface water model river water quality (RIVWQ) 2.02. in order to predict the environmental concentrations of pesticides in groundwater (GW) and surface water (SW) systems within a rice area. The annual average pesticide concentrations at 1 m depth, predicted by RICEWQ were used to assess the risk for GW contamination. The predicted exposure concentrations derived through modelling and eco-toxicological endpoints obtained from the literature, were used to calculate acute and long-term toxicity exposure ratios (TERs) for aquatic organisms. Application of these scenarios with RICEWQ and RIVWQ models enabled us to perform a risk assessment exercise for several herbicides registered in Greece for use in rice. Such a risk assessment approach could be further scaled up to represent a whole rice cultivated basin in order to be used for regulatory purposes.     

Growth,Nutritional Status,Chlorophyll Content,and Antioxidant Responses of the Apple Rootstock MM 111 Shoots Cultured Under High Boron Concentrations In Vitro

The in vitro response of the apple rootstock MM 111 to increasing concentrations of boron (B) (0.1, 0.5, 1, 3, and 6 mM) in MS medium is reported. The in vitro cultures of MM 111 shoots produced the highest fresh mass when 0.1 mM B was included in the medium. By increasing B concentration of the culture medium from 0.1 to 6 mM, B, phosphorus (P), calcium (Ca), and magnesium (Mg) concentrations of explants increased, whereas potassium (K), iron (Fe), manganese (Mn), and zinc (Zn) concentrations decreased. Chlorophyll content (SPAD units) of leaves declined as B concentration of the culture medium increased from 0.1 to 6 mM. The highest peroxidase (POD) activity in leaves was recorded in the presence of 6 mM B in the medium. By increasing B concentration of the medium from 0.1 to 3 mM, catalase (CAT) activity increased in leaves. Superoxide dismutase (SOD) activity in leaves and stems increased as B concentration of the medium increased. The non-enzymatic antioxidant power activity of leaves (FRAP values) increased gradually as B concentration of the medium increased.     

Pathogenicity of three entomopathogenic fungi on pupae and adults of the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae)

The pathogenicity of local isolates of the entomopathogenic fungi (EPF) Beauveria bassiana (Balsamo) Vuillemin, Isaria fumosorosea (Wize) (formerly Paecilomyces fumosoroseus (Wise) Brown & Smith) and Metarhizium anisopliae (Metschnikoff) Sorokin (Ascomycota: Hypocreales) were evaluated under laboratory conditions against pupae and adults of Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) via different routes of exposure. Average mortality of pupae after immersing them into spore suspensions was in general low and ranged from 18.7 to 23.9 % depending on fungal species and dose applied. However, adults obtained from treated pupae appeared to have higher mortality rates compared to control with all fungi and doses tested. Adults’ average mortalities ranged from 41.9 to 88.0 % after exposing them to EPF either by feeding on a mixture of conidial suspension and artificial food or by bodily contact with conidia, depending on fungal species, dose and method of exposure. The proportion of cadavers, pupae or adults, that produced visible signs of mycosis ranged from 40.4 to 73.3 % with the exception of those that were exposed to M. anisopliae. In that case, none of the insects that died after exposure to conidia of M. anisopliae developed visible mycelium on their surface. Moreover, confining treated with untreated adults indicated horizontal conidial transmission in some cases. Our results indicate that EPF might be a promising biological control agent for the Mediterranean fruit fly and could be utilised with different modes of application: soil application against pupae and cover or bait sprays against adults.     

Spatial heterogeneity of ambient sound at the habitat type level: ecological implications and applications

While spatial heterogeneity is one the most studied ecological concepts, few or no studies have dealt with the subject of ambient sound heterogeneity from an ecological perspective. Similarly to ambient light conditions, which have been shown to play a significant role in ecological speciation, we investigated the existence of ambient sound heterogeneity and its possible relation to habitat structure and specifically to habitat types (as syntaxonomically defined ecological units). Considering that the structure and composition of animal communities are habitat type specific and that acoustic signals produced by animals may be shaped by the habitat’s vegetation structure, natural soundscapes are likely to be habitat specific. We recorded ambient sound in four forest and two grassland habitat types in Northern Greece. Using digital signal techniques and machine learning algorithms (self organizing maps, random forests), we concluded that ambient sound is not only spatially heterogeneous, but is also directly related to habitat type structure, pointing towards the existence of habitat type specific acoustic signatures. We provide evidence of the importance of soundscape heterogeneity and ambient sound signatures and a possible solution to the social cues versus vegetation characteristics debate in habitat selection theory.     

The impact of biological pesticides on arbuscular mycorrhizal fungi

Arbuscular mycorrhizal (AM) fungi have a key role for plant nutrition in organic farming systems where crop protection relies on biopesticides. Although these are considered safe, their effects on non-target organisms, such as AM fungi, are not known and should be evaluated. A pot and a field experiment were employed to investigate the impact of biological pesticides (azadirachtin, spinosad, pyrethrum and terpens) on exogenous AM fungal inoculum (pots) and on indigenous AM fungi (field). The synthetic fungicide carbendazim and non-pesticide treated controls with or without mycorrhizal inoculation were also included. Plant growth and root colonization were measured 20 and 40 days post inoculation (dpi) in the pot experiment, or 40 and 90 dpi in the field study. Pesticide effects on the structure of the intraradical AM fungal community were determined via DGGE and cloning. Spinosad, pyrethrum and terpenes did not affect the colonization ability and the structure of the AM fungal community. On the contrary, pot application of azadirachtin resulted in a selective inhibition of the Glomus etunicatum strain of the inoculum. DGGE analysis showed that the field application of azadirachtin induced significant and persistent shifts in the AM fungal community. Carbendazim completely hampered mycorrhizal colonization in pots, compared to its field application which had a transitory effect on the colonization ability and the community structure of indigenous AM fungi. Our study provides first evidence for the effects of biological pesticides on the diversity of AM fungi.