Yasmine Lakhdari (1)*, Abdelhakim Bouzid (2,3), Makhlouf Sekour (2), and Stéphane Aulagnier (4)

1. Laboratoire de Mathématiques et Sciences Appliquées (LMSA), Faculté des Sciences et de la Technologie, Université de Ghardaïa, 47000 Ghardaïa, Algeria.
*E-mail: lakhdari.yasmine@univ-ghardaia.dz
2. Laboratoire des Bio-ressources Sahariennes: Préservation et Valorisation (BRS), Université de Ouargla, 30000 Ouargla, Algeria. E-mail: sekkmakk@yahoo.fr
3. Laboratoire de Conservation des Zones Humides (LCZH), Université de Guelma, 24000 Guelma, Algeria. E-mail: bouzid.abdelhakim@univ-ouargla.dz
4. Comportement et Écologie de la Faune Sauvage, INRAE, Université de Toulouse, CS 52627,31326 Castanet-Tolosan CEDEX, France. E-mail: stephane.aulagnier@inrae.fr

The barn owl, Tyto alba (Scopoli, 1769), is an opportunistic nocturnal predator which diet tracks ecological changes in its habitat. To assess temporal dietary changes in a Saharan palm grove ecosystem, 402 pellets were collected between July 2022 and August 2023 in the Ranou palm grove (Touggourt, Southeastern Algeria) and compared with baseline data from 2009–2010 published by Hadjoudj et al. (2020). A total of 1353 prey items belonging to 29 species across four taxonomic classes were identified. Mammals dominated the diet in terms of relative abundance and estimated biomass. Commensal rodents increased markedly over the study period, particularly Mus musculus (Linnaeus, 1758) and Rattus rattus (Linnaeus, 1758), with the latter accounting for 47.7 % of the total biomass. Conversely, desert-adapted species of Gerbillus (Desmarest, 1804) declined significantly, while bird prey increased markedly, with Palaearctic migrants recorded for the first time. The reptilian component shifted from Lacertidae to Gekkonidae. Predation on the cricket Brachytrupes megacephalus (Lefebvre, 1827), a major agricultural pest in Saharan environments (Gryllidae), suggests a potential contribution of T. alba to regulating agricultural pest populations. These findings highlight the value of temporal dietary monitoring in assessing ecological changes and biodiversity dynamics in arid environments.

Received: 24 May 2026 / Accepted: 19 July 2026 / Available online: 06 August 2026 Open

Access: This work is distributed under the Creative Commons Attribution 4.0 License.

Vira Moroz

Department of Agrobiotechnologies, West Ukrainian National University, 11 Lvivska Str.,
Ternopil 46009, Ukraine. E-mail: morozvira96@gmail.com

Under global climate change, forest ecosystems play an increasingly important role as carbon sinks, while the carbon accumulation capacity of Scots pine stands is strongly influenced by stand age, forest site conditions, and ecological status. Regionally adapted phytomass models are therefore required to improve carbon-stock assessment, support reforestation planning, and estimate potential losses caused by forest degradation, fires, and logging. This study aimed to develop models of the above-ground phytomass of Scots pine stands in the Ukrainian Polissya and its north-western outskirts, taking into account stand age, bioproductivity, and forest site type to assess their carbon accumulation potential. The research was conducted in 2023–2024 within the Volyn, Rivne, and Zhytomyr regions. It covered 302 temporary sample plots established in natural Scots pine stands of varying ages (8–100 years) in accordance with the national standard. The results showed that the average density of above-ground phytomass ranged from 160–180 kg·m–2 in loamy sand infertile pine site types to 440–465 kg·m–2 in moist fairly infertile pine site types, where middle-aged and mature high-yielding stands with high density and well-developed crown mass predominate. In fresh fairly infertile pine site types, phytomass was 310–345 kg·m–2, while in dry fairly infertile pine site types, it was 190–230 kg·m–2. Mathematical modelling enabled the construction of logarithmic regression models describing the relationship between stand age and the specific phytomass conversion coefficients for wood, bark, and crown. It was established that conversion coefficients decrease with stand age, reflecting the regular reduction in the specific mass of individual fractions. The practical significance of these results lies in their application to spatial planning of reforestation, assessment of carbon potential, and the development of climate-oriented forest policy in conditions similar to those of the Ukrainian  Polissya and its north-western outskirts.

Received: 10 April 2026 / Accepted: 21 July 2026 / Available online: 06 August 2026

Open Access: This work is distributed under the Creative Commons Attribution 4.0 License.

Boyka Malcheva (1)* and Anna Bakalova (2)

1. Department of Silviculture, Faculty of Forestry, University of Forestry, 10 Kliment Ohridski Blvd., 1797 Sofia, Bulgaria. *E-mails: b_maltcheva@ltu.bg

2. Department of Plant Production, Faculty of Manufacturing, Engineering and Technologies,
Technical University of Varna, 1 Studentska Str., 9010 Varna, Bulgaria.
E-mail: anna_bakalova@abv.bg

The aim of this study was to evaluate the seasonal microbiological and enzymatic responses of urbogenic soils beneath introduced ornamental tree and shrub species in urban areas of Burgas and Sozopol along the Southern Black Sea coast of Bulgaria. Soil samples were collected under Ligustrum lucidum W.T.Aiton, Magnolia liliiflora ‘Nigra’, Musa paradisiaca L., Nerium oleander L., Photinia × fraseri ‘Red Robin’, Pinus pinea L., Prunus serrulata ‘Kanzan’ and Trachycarpus fortunei (Hook.) H.Wendl. from two soil layers during spring, summer and autumn. The abundance and composition of the main microbial groups, total microbial count, mineralisation coefficient, cellulase and catalase activities, soil pH, humus content, temperature and moisture were determined. The microbial status showed pronounced spatial differentiation and a general decrease in total microbial abundance with depth. The highest total microbial count was recorded under N. oleander, whereas the lowest values were found under T. fortunei. Non-spore-forming bacteria dominated the microbial community, followed by bacilli, while actinomycetes and filamentous fungi were less abundant. Seasonal dynamics of total microbial count and enzyme activities showed higher values in autumn at most sites, followed by spring, whereas summer maxima were observed in the surface soil layers at two sites under favourable soil moisture conditions. Two-way analysis of variance showed that season did not significantly affect the analysed parameters, whereas soil depth significantly affected total microbial count, cellulase and catalase activities. Cellulase activity was higher in the surface layer and slightly increased in autumn at most sites, whereas catalase activity followed a similar spatial pattern. The mineralisation coefficient varied considerably among sites and was not directly related to total microbial abundance. Spearman correlation analysis identified humus content as the factor most strongly associated with microbial abundance and enzymatic activity. Overall, the results confirm the value of combining microbiological, enzymatic and physicochemical indicators for assessing the biological quality of urbogenic soils.

Received: 01 July 2026 / Accepted: 26 July 2026 / Available online: 10 August 2026

Open Access: This work is distributed under the Creative Commons Attribution 4.0 License.

Zornitsa Karcheva*, Stilyan Angelov, and Svetoslav Anev

Department of Dendrology, Faculty of Forestry, University of Forestry, 10 Kliment Ohridski Blvd., 1797 Sofia, Bulgaria. *E-mail: z.karcheva@ltu.bg

This study aimed to compare the geographical distribution, ecological characteristics and phenological behaviour of forests dominated by Picea abies (L.) H.Karst. and Abies alba Mill. in Bulgaria, combining data from the National Forest Inventory and remote sensing. Ecological variables such as altitude, latitude, longitude, aspect, and slope were analysed to characterise species- specific habitat preferences. Phenological events, including the start of the vegetation period (SVP), the end of the vegetation period (EVP), and the length of the vegetation period (LVP), were also compared. The results indicated that in Bulgarian forests, P. abies dominates significantly more stands than A. alba. Both species are mainly found in the middle mountain zone, but the average altitude of spruce forests is 1507.6 ± 170.8 m, while that of fir forests is notably lower at 1371.1 ± 164.7 m. Both species favour sloping terrain, with fir tolerating steeper slopes (17.8° ± 7.2°), whereas spruce is more common on moderate slopes (14.8° ± 6.2°). They prefer shady exposures, though spruce shows greater tolerance to sunny conditions (61.5 %/38.5 %), while fir is more restricted to shaded exposures (77.7 %/22.3 %). P. abies begins its active vegetation period (SVP) early (~10 April ± 13.7 days), whereas A. alba delays SVP by over a week (~18 April ± 9.9 days). EVP also occurs earlier in spruce forests (~24 September ± 12.5 days), while in fir forests it is delayed by more than a week (~3 October ± 10.8 days). As a result, in both spruce and fir forests, LVP lasts approximately 167.2 ± 20.3 days. These findings enhance our understanding of the ecological and phenological differences between the two conifers and can be utilised to improve the efficient, evidence-based management of forests dominated by these species in Bulgaria, which may be important for addressing the challenges posed by climate change.

Received: 19 June 2026 / Accepted: 31 July 2026 / Available online: 12 August 2026

Open Access: This work is distributed under the Creative Commons Attribution 4.0 License.

Reshma Persaud* and Abdullah Adil Ansari

Department of Biology, Faculty of Natural Sciences, University of Guyana, Georgetown,
Guyana. E-mails: reshma.persaud@uog.edu.gy*, abdullah.ansari@uog.edu.gy 

Earthworms serve as vital bioindicators of soil health and are significant regulators of soil structure and organic matter dynamics in terrestrial ecosystems. In the face of intensifying an thropogenic pressures on soils and global climate, earthworm populations are increasingly vul nerable to the strains imposed by agriculture, mining, and deforestation. This study aimed to characterise earthworm assemblage structure across Guyana and to evaluate the influence of bi ogeographical, climatic, and edaphic factors on earthworm communities and ecotype distribution. Earthworms and soil samples were collected from 60 sites. Earthworms were methodologically dissected to aid in their identification, and soil samples were analysed for 16 parameters. A total of 68 morpho-species of earthworms from 8 families were identified. Of the four biogeographical re gions, the Highland Region exhibited the highest diversity, species richness and abundance. Sta tistical analysis revealed that soil, habitat and biogeography significantly influenced earthworm abundance and distribution of ecotypes. Soil analysis revealed that earthworm abundance was significantly correlated with soil calcium (R2 = 0.07, p = 0.006), phosphorus (R2 = 0.06, p = 0.006) and iron (R2 = 0.05, p = 0.016). Endo-anecic abundance was negatively correlated with calcium (-1.6) and iron (-1.8) and anecic abundance was positively correlated with phosphorus (+1.1) and negatively correlated with calcium (-1.1). Multivariate analysis revealed that soil type (R2 = 0.39, p < 0.001), habitat type (R2 = 0.19, p = 0.011) and geography (R2 = 0.16, p < 0.001) were the most significant drivers of the ecotype composition of earthworm communities. These findings provide a critical baseline for understanding the edaphic and climatic filters that shape soil biodiversity in the Guiana Shield and reinforce the sensitivity of specific ecotypes to land-use changes. 

Received: 07 April 2026 / Accepted: 11 August 2026 / Available online: 24 August 2026

 Open Access: This work is distributed under the Creative Commons Attribution 4.0 License.