Volume 49 (2022): Edition 2 (July 2022)

The difficulty of locating and measuring the over-bark tree bole diameters at heights that are far from the ground, is a serious problem in ground-truth data measurements in the field. This problem could be addressed through the application of intelligent systems methods. The paper explores the possibility of applying the Random Forest regression method (RFr) in order to assess, as accurately as possible, the size of the tree bole diameters at any height above the ground, considering data that can be easily measured in the field. For this purpose, diameter measurements of pine trees (Pinus brutia Ten.) from the Seich–Sou urban forest of Thessaloniki, Greece, were used. The effectiveness of the Random Forest regression technique is compared with the results of non-linear regression models that fitted to the available data and evaluated. This research has shown that the RFr method can be a reliable alternative methodology in order to receive accurate information provided by the model, saving time and effort in field.

During the spring of 2020, Choristoneura murinana (Hubner) otherwise European Fir Budworm (EFB) was recorded on Abies cephalonica near the villages of Kaloskopi and Agoriani in Central Greece at the mountains Giona and Parnassus respectively. To our knowledge, the occurrence of the particular pest on the specific mountains has not been described yet. We found that EFB mostly prefers Abies cephalonica and less Juniperus oxycedrous in sunny areas and/or near the country roads. Across the study area, local severe infestations of scale 2, 3 and 5, were observed. In many cases the infestation was observed in adult fir individuals. Defoliations and severe outbreaks, which are presumably incurred by EFB were also observed by local people (beekeepers, foresters, herb collectors) in the past. Our laboratories field measurements and the analysis of the Singular Spectrum analysis trendlines revealed growth decline, not connected with climatic parameters but probably associated with observed defoliations by the EFB.

Passive acoustic monitoring is a wildlife monitoring method used especially for the study of vocally active species which are difficult to observe directly. The tawny owl (Strix aluco, Linnaeus 1758) is such a species, and has not been previously studied in Greece. The aim of the study was to provide a first insight into the species’ acoustic ecology in the Rhodope Mountains by describing its calling activity at four sites over a period of 3–6 months, and to examine possible correlation with natural and climatic parameters. Based on 24,937 calls, we report a significant increase in the number of calls per night (18:00 pm to 9:00 am) as the length of the night increased, as well as a negative relation with wind speed. We did not observe a relationship between calling frequency and the phase of the moon.

This paper investigates leaf morphology variation of the strawberry tree (Arbutus unedo) within and between two natural contrasting populations of significant latitudinal difference (Kassandreia, Chalkidiki and Ancient Olympia, Peloponnese). This study employed 11 leaf size and shape parameters, recorded by image processing and analyzing software. The results showed that in the measurements of central tendency (parameter means) the northern population of Kassandreia presented the highest values, while in contrast the highest values in the measurements of spread were found in the southern population of Ancient Olympia. Moreover, statistically significant differences between populations were detected in leaf size, but not in leaf shape parameters. Results are discussed in the context of their value in studying quantitative population differentiation and laying the basis of more advanced studies.

The multifaceted role of deadwood in forest ecosystems has been widely recognized while it is regarded as an indicator of sustainable forest management. Nevertheless, there are hardly any data on deadwood volume and structure in managed forests in Greece. The study took place in beech forests of the Western and Central part of the Rodopi Mountain Range. The objective was to determine the amount, variability and quality of deadwood and to compare it with data from managed as well as natural forests. Data were collected on 30 randomly distributed circular plots of 0.1 ha. The results showed that the average deadwood amount (13.46 m³ ha⁻¹) was much lower compared to that recorded in other European forests and they highlighted the absence of large dead standing trees due to the management regime. The deadwood quality showed great variation in stages of decay.

Antioxidants enhance the salt tolerance of date palms. A field experiment was carried out on date palm offshoots to improve the salt tolerance of the Sayer cultivar. Salicylic acid and citric acid (500 and 1,000 ppm) were used. The results showed that all growth parameters of plant height, leaf area, and leaf numbers decreased under the salinity conditions. The antioxidant applications increased the plant height, leaf area, carbohydrates, and relative water content compared with the control. Citric acid at 1,000 ppm decreased electrolyte leakage and malondialdehyde. Indoleacetic acid decreased, whereas abscisic acid increased under salinity. The antioxidant application increased indoleacetic, whereas abscisic acid decreased. Proline, protein content, and peroxidase activity increased under antioxidants. Also, the potassium and K/Na ratio increased under antioxidant applications. Citric acid improved the characteristics more than salicylic acid, encouraging farmers to use it for its low cost as an antioxidant to reduce environmental stress damage.

The aim of the study was to assess the current state and productivity of black alder (Alnus glutinosa (L.) Gaertn.) stands and determine the optimal conditions for the emergence and further growth of its natural regeneration in Ukrainian Polissya. The area of black alder stands in Ukrainian Polissya (Ukrainian forest zone) is 162,348 ha, reaching 8.4% of the total forest area. Volyn Region has the largest area of alder stands within Ukrainian Polissya (61,271 ha covering 37.7% of the total area). In the forests of this region, a more detailed study of the current condition, productivity, growth and regeneration of alder stands was performed. The natural regeneration under the alder canopy was characterized as poor. The largest numbers of alder seedlings (1,600–1,800 stems per ha) were recorded under the canopy of 76–78-year-old stands with a relative density of stocking of 0.63–0.70 and 80–100% of alder in their composition. Naturally regenerating alder seedlings had mainly group distribution on the area (occurrence is up to 40%). These specificities should be taken into account to promote natural seed regeneration of alder stands.

This study aimed at clarifying species composition and ecological structure of the ground beetles associated with oilseed rape fields during flowering, ripening and post-harvest, as well as pastures adjacent to them. Field work was carried out in 2017. Pitfall traps (5 in each site) were set in 20 sampling sites in the Transylvania region, Cluj County. A total of 8,151 individuals were collected (7,576 in rapeseed fields and 575 in pastures) belonging to 82 species from 29 genera. The richest tribes were Harpalini (25 species), Zabrini (12 species), Pterostichini (10 species), and Carabini (9 species). The most species-rich were the genera Harpalus (13 species), Amara (11 species), Carabus and Ophonus (8 species each). The most abundant species in the rape fields were Poecilus cupreus (1,760 ind.), Brachinus explodens (1,500 ind.), Brachinus elegans (1206 ind.), and Anchomenus dorsalis (875 ind.). The most abundant in the grasslands were Pterostichus hungaricus (101 ind.), Calathus fuscipes (74 ind.), Harpalus caspius (67 ind.), and Cylindera germanica (64 ind.). The species found only in rape fields were 36 while 13 species were exclusive to pastures; 34 species were discovered in both types of habitats. The investigation acquired some new data on carabid diversity in Romania, including two new country records.

Cities intensely modify natural environments and impose pressures on biodiversity. In this sense, carnivorous mammals are one of the groups most affected due to their food and space requirements. The feeding and spatial behavior of the chilla fox (Lycalopex griseus, G., 1837) and dogs were studied in the vicinity of a peri-urban protected area in south-central Chile. The diet of both canids was compared seasonally, for which feces were collected along trails in three habitats: native forest, exotic plantations and scrublands. Dog feces were collected at the same site to establish whether they were avoided by foxes. Chilla fox has been highlighted for consuming a high proportion of hares followed by rodents of the Muridae family, both being exotic mammals in Chile, whereas dogs showed a predominant consumption of anthropogenic food. Significant differences were observed for chilla fox in dietary diversity, mainly in summer and fall. No spatial segregation was observed with the domestic dog, which was evidenced in a high overlap in the use of all habitats. This scenario, together with continuous human presence, are elements that must be considered in the medium-term to evaluate the effects of anthropogenic pressures on native carnivores in the study area.

Understanding cases in restoration and in agriculture in which species diversity improves productivity and ecosystem functioning is crucial due the need to restore degraded habitat and improve crop productivity for a growing human population. Reaching these diversity benefits is likely influenced by the dynamic of less negative interspecific than intraspecific interactions that promote diversity. But further testing is needed to understand the relationship of intraspecific-relative to interspecific interactions. Here I used seedlings from three native and one introduced species used in restoration in the western United States in pairwise interaction combinations and found that the study species varied in shoot biomass in response to interaction treatments of the control, intraspecific, and interspecific interactions (R² = 0.7, p < 0.001), and that intraspecific interactions were more negative than interspecific interactions for four of five of the pairings. Overall, as shoot mass size differences increased between interspecific neighbors, interactions became more positive (R² = 0.6, p < 0.001). These findings point to variability in species responses in whether the focal species compete more intensely with conspecific or heterospecific neighbors and indicates the need for more careful selection of interacting species for meeting both agricultural and restoration goals.

The latest findings on the taxonomic review of Quercus faginea Lam. complex using ‘traditional morphometrics’, demonstrating that the species is represented in Algeria by both Q. faginea and Q. canariensis Willd. Significant variations of the leaf form were also discernible among both species. In this study, the landmark-based geometric morphometrics analysis was used to assess the shape variation of the leaves found on oak stands. 2,600 leaves per 13 stands were collected and scanned, and then using Tps range and MorphoJ software, 11 landmarks—that represent the leaf morphological features—were recorded on leaf images. Shape components and non-forms variations were obtained through a full Procrustes fit followed by creating a leaf-superimposed configuration. Principal component analysis, canonical variate analysis, and discriminate analysis were used to statistically evaluate the leaf shape variability. The results revealed no clear distinction between the two species based on leaf shape. Climate change and environmental factors also appear to have possibly caused a divergent morphological evolution; a reduced leaf size with enduring indumentum—among other Q. faginea traits—could be an efficient mean of adapting to Mediterranean xeric conditions.

Invasive and alien plant species (IAPS) are considered as major threats to native biodiversity because IAPS alter ecosystem structure and their functions. We assessed the association of four major IAPS (Mikania micrantha, Chromolaena odorata, Lantana camara, and Parthenium hysterophorus) and the abundance of wild ungulates in Barandabhar Corridor Forest (BCF), Chitwan, Nepal. We collected data on the presence of wild ungulates in IAPS invaded habitats through direct observation and sign surveys. Our study showed that the cover of M. micrantha was significantly high in Sal forest (Prominence value PV = 73.23) followed by riverine forest (PV = 40.5) and grassland (PV = 37.7) whereas P. hysterophorus was high in grasslands (PV = 22.9). Similarly, C. odorata was significantly high in Sal forest (PV =141.6%), and L. camara was high in mixed forest (PV = 22.6). It was found that there was a significant negative association of IAPS (p = 0.002) with wild ungulates. The abundances of deer and wild pigs were more in the buffer zone than in the non-buffer zone. The abundance of deer decreased with increasing cover of C. odorata, M. micrantha, and P. hysterophorus (p = 0.002). Similarly, the abundance of wild pigs decreased with increasing cover of M. micrantha and L. camara. IAPS were not uniformly distributed in different habitats and abundances of wild ungulates were less in IAPS invaded habitats. Hence, it is important to initiate management plans to control IAPS spread to avoid their negative impacts on wild ungulate population such as deer and wild pigs.