Issues

Abstract

This study provides the first quantitative estimates of key reproductive parameters for the endangered Mandra shemaya (Alburnus mandrensis Drensky, 1943) (IUCN Red List) from two tributaries, the Rusokastrenska and Sredetska rivers, of the Mandra Reservoir in Bulgaria. Samples were collected during four years, from 2020 to 2023. Of the 334 fish captured by angling, 184 were with developed gonads. The youngest mature individual was a three-year-old female (96 mm, 5.3 g). Absolute fecundity ranged widely from 190 to 75,565 eggs, with a mean of 8,859 eggs, and showed a strong positive correlation with fish standard length, gutted weight, and age. Fecundity increased until the ninth year, after which a decline was observed in the older (11- and 12-year-old) fish. The average relative fecundity was 351 eggs per gram of gutted weight. These results establish an important baseline for understanding the reproductive biology of this endemic species and are instrumental for its future conservation and management.

Received: 27 October 2025 / Accepted: 31 December 2025 / Available online: 09 January 2026

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

Abstract

Agroforestry systems in Social Forestry areas often face persistent challenges in achieving comprehensive sustainability, particularly in economic and socio-institutional dimensions. Despite their potential to enhance livelihoods and environmental resilience, limited studies have integrated multidimensional evaluations to identify the key leverage factors and policy priorities for sustainable agroforestry. This gap highlights the urgency of developing holistic strategies tailored to local institutional contexts. This study aims to formulate sustainable agroforestry strategies in Barru District, focusing on Social Forestry areas using the RAPFISH–AHP approach, and emphasising ecological, economic, and socio-institutional aspects. The sustainability assessment employed multidimensional scaling with the RAPFISH framework, complemented by the Analytical Hierarchy Process (AHP) to prioritise strategies derived from sensitive attributes identified through leverage analysis. The research involved 15 active members of the Mega Buana Forest Farmers Group in Pacekke Village through participatory observation and structured Likert-scale questionnaires. The results show that agroforestry in the study area is ‘less sustainable’ in economic (index 38.91) and socio-institutional (38.10) dimensions, and ‘moderately sustainable’ in the ecological dimension (47.56). The most sensitive factors influencing sustainability include the selling price of agricultural products, chemical fertiliser use, and the institutional role of Forest Farmer Groups. Based on AHP results, two key strategies were prioritised: (1) optimising local institutions and participatory technical assistance (67.4 %), and (2) developing downstream community-  based agroforestry business models (32.6 %). These strategies provide an integrated policy framework to strengthen institutional capacity, enhance adaptive governance, and promote environmentally responsible practices within Indonesia’s Social Forestry areas.

Received: 09 July 2025 / Accepted: 04 December 2025 / Available online: 10 December 2025

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

Abstract

The Mandra shemaya is an endemic species of Bulgaria. It is found only in the Mandra Reservoir and in the rivers that flow into it. Information about its biology is important for its conservation and preservation. Due to the lack of detailed data on its population biology, we aimed to study certain population parameters of this species. This study investigates the age structure, growth rate, and condition of Alburnus mandrensis (Drensky, 1943) (commonly known as the Mandra shemaya) in two tributaries of the Mandra Reservoir: Sredetska and Rusokastrenska rivers. Field data were collected  ver four consecutive years (2020–2023), with a total sample of 334 individuals. The primary aim was to assess the speciesʼ growth characteristics and condition in its natural habitat. The majority of specimens were five to seven years old, with the most frequent length group ranging from 101–150 mm. Overall, total length varied between 77 and 223 mm, and total weight ranged from 3.1 to 100.9 g. The relationship between body length (L) and scale radius (S) was expressed as L = 1.4187·S + 26.43 (r² = 0.96), whereas the weight–length (WLR) relationship followed the equation W = 0.0000007·L3.4919 (r² = 0.99). These results suggest a relatively slow growth rate for A. mandrensis. To date, this is the first detailed investigation of this endemic   species within the Mandra Reservoir watershed. 

Received: 13 August 2025 / Accepted: 04 December 2025 / Available online: 10 December 2025

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Abstract

In Indonesia, wood from fast-growing tree species that are planted in community forests plays an important role in meeting the raw material demands of the wood industry. One of these is Falcataria falcata (L.) Greuter & R.Rankin. This study aimed to determine the radial variation of wood properties of F. falcata grown in a community forest in Indonesia by linear and nonlinear mixed-effect models. Based on radial variation modelling, the linear model was selected as the best model for basic density and compressive strength parallel to grain, indicating that these properties increase gradually from pith to bark. Meanwhile, the logarithmic model was fitted for radial shrinkage and modulus of elasticity (MOE), and the Michaelis-Menten model was selected for tangential shrinkage and modulus of rupture (MOR). Both of these models indicated that radial and tangential shrinkage at 1% moisture content, as well as MOE and MOR, increased from the pith and then became almost constant toward the bark. It can be concluded that the outer part of F. falcata shows potential for use in products requiring higher strength, such as lightweight structural components, panels, and raw materials for wood-based composites, although further validation is needed.

Received: 31 July 2025 / Accepted: 25 November 2025 / Available online: 01 December 2025

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Abstract

This study investigates drupe and seed traits, as well as seed viability, of Pistacia lentiscus L. across six sites distributed along a latitudinal gradient in Algeria. At each site, ten shrubs from wild populations were randomly selected for sampling. One hundred mature drupes per shrub were collected in 2018 and 2019 and analysed for various quantitative and qualitative traits. No significant differences were observed between years for quantitative traits, but significant variation was detected among sites. Drupes from the northernmost sites were heavier but contained smaller seeds compared to those from southern sites. Seed weight represented approximately 25 % of drupe weight. On average, seed viability was 18.94 %, although at two of the six sites it reached 35 to 47 %, with a few individuals showing up to 91 %. At the other sites, particularly in semi-arid areas, viability was low and sometimes zero. Principal Component Analysis (PCA) based on the drupe and seed features allowed discrimination between the two northernmost sites and the others. In contrast, qualitative traits such as colour, shape, and surface were relatively consistent across sites. This study provides the first evidence of geographic variation in reproductive parameters such as drupe and seed weight, seed size, and seed viability in P. lentiscus populations in Algeria. Such variation may influence the species’ capacity to regenerate through seeds.

Received: 21 July 2025 / Accepted: 11 November 2025 / Available online: 20 November 2025

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Abstract

This study examined the distribution and phenology of forests dominated by Quercus cerris L. (QC), Quercus frainetto Ten. (QF) and Quercus petraea sensu lato (QP) across Bulgaria. Ecological variables, including altitude, latitude, longitude, aspect and slope, were analysed to characterise species-specific habitat preferences. Phenological events, such as 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 showed that QC and QF were more common on flat terrain, whereas QP preferred mountainous areas. QC tended to dominate shaded slopes, QF occurred mainly on sunny exposures, and QP was more evenly distributed across both. QC exhibited the latest leaf unfolding (20 April ± 4.8 days) and the earliest EVP (15 October ± 12.8 days), resulting in the shortest growing season (178.1 ± 13.8 days). In contrast, QF and QP began vegetation period almost simultaneously (16–18 April ± 4.8–6.6 days) and ended at similar times (20–23 October ± 9.4–12.9 days), with comparable vegetation periods (187–188 days). Observed features enhance our understanding of the ecological and phenological differences among the three oak species. They can be utilised to improve the efficient, evidence-based management of oak forests in Bulgaria, which may be crucial in the face of climate change challenges.

Received: 08 October 2025 / Accepted: 11 November 2025 / Available online: 14 November 2025

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Abstract

Atlas cedar, Cedrus atlantica (Endl.) Manetti ex Carrière, a cornerstone of North African forests, is increasingly threatened by habitat fragmentation and desertification in its southern range. This study aims to assess how morphological traits of cones, seeds, and needles vary among provenances to infer local adaptation to contrasting environments. Understanding local adaptation is therefore crucial for conservation. This study evaluates morphometric variation in cones, seeds, and needles among three Algerian provenances (Oued Tider, Ain Kerrouch, Talmet) within Belezma National Park, where Saharan influences constrain regeneration. From each provenance, 10 cones were sampled from 10 trees and analysed for weight, length, diameter, and scale number. For each cone, the total number of seeds was counted, and individual seeds were measured for weight, length, diameter, and thickness. In addition, seed-to-cone mass ratio was calculated to quantify reproductive efficiency. Besides, needle length and diameter were also measured. Results revealed significant provenance differences in cone weight, length, diameter, and scale count. Talmet cones were the largest and seed weight highest, followed by Ain Kerrouch and Oued Tider. Seed length and diameter were also greater in Talmet, while needle length peaked in Ain Kerrouch. Strong allometry emerged among cone dimensions and between cone and seed weight, but not with needles. These morphological patterns mirror local environmental gradients; Oued Tider’s wetter climate favoured smaller cones and seeds, Talmet’s harsher soils and aridity promoted larger reproductive investment, and Ain Kerrouch displayed intermediate traits with longer needles. Overall, provenance-specific contrasts in seed size and yield highlight environment-driven shifts in reproductive allocation, supporting evidence of local adaptation to semiarid gradients. These findings highlight adaptive divergence among provenances, offering critical guidance for seed-source selection under advancing desertification.

Received: 08 October 2025 / Accepted: 10 November 2025 / Available online: 12 November 2025

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Abstract

Taï National Park (PNT) is drained mainly by Hana River, which rises outside it. It provides a source of water for the park’s many animals and is an important ecosystem for maintaining Ivorian biodiversity. However, the river has been severely degraded by artisanal and illegal gold mining. It carries a load of pollutants into the Park from mining activities conducted upstream on the outskirts of the PNT. The general objective of this study is to study the development of land use, in particular, the dynamics of illegal artisanal gold panning in Hana River source area between 2021 and 2024 to improve park management. To achieve this, the methodology relies on the processing of Sentinel-2 satellite images. The classification of these images was carried out using the Random Forest algorithm and validated with several performance tests. Analysis of land-use change showed a significant increase in artisanal gold panning and food crops, with annual increases of 120.5 % and 14.1 % respectively. However, fallow land and water areas experienced a decrease in surface area, with regression rates of 21.7 % and 28.5 % respectively. The study highlighted the risks and dangers of illegal artisanal gold panning for Taï National Park. To preserve this natural heritage, it is imperative to prohibit gold panning activities in the peripheral zone of the Park and to implement measures for the ecological restoration of abandoned sites.

Received: 14 July 2025 / Accepted: 28 September 2025 / Available online: 16 October 2025

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

Abstract

Indigenous forest governance has received growing recognition worldwide, yet its integration with modern spatial technologies remains limited in Southeast Asia. This study explores the integration of GIS with Traditional Ecological Knowledge (TEK) to analyse the structure and function of the Customary Forest Management Unit (CFMU) in Toro customary forest, Central Sulawesi, Indonesia. Toro community, renowned for its intricate customary zoning, faces contemporary hallenges of tenure insecurity, external encroachment, and ecological pressure, creating an urgent need for hybrid governance approaches. A mixed-methods framework was employed, combining high-resolution satellite imagery, GIS-based Multi-Criteria Evaluation (MCE), GPS surveys, and participatory mapping with 35 community stakeholders, complemented by interviews and field observations. Toro forest, covering 20,276.98 ha, was classified into three functional categories: limited production forest (11,629.41 ha; 57.35 %), protected forest (6,292.22 ha; 31.03 %), and permanent production forest (2,355.35 ha; 11.62 %). MCE model achieved 88.7 % accuracy (Kappa = 0.83). Six customary zones were delineated – Wana Ngkiki, Wana, Pangale, Pahawa Pongko, Oma, and Balingkea – each serving distinct ecological and socio-cultural purposes. Overlay analysis revealed strong congruence: more than 90 % of core zones (Wana Ngkiki and Wana) coincide with steep slopes and intact forests, while over 70 % of peripheral zones (Oma and Balingkea) correspond with agroforestry mosaics. Findings confirm that Toro’s concentric zoning is not only a cultural construct but also ecologically rational, simultaneously safeguarding biodiversity in core areas and supporting diversified livelihoods through agroforestry and non-timber forest products. This dual outcome underscores the role of customary governance as both an ecological safeguard and a foundation for green economic pathways. Beyond its local relevance, Toro case contributes to global discourses on biocultural conservation and sustainable development. By demonstrating how TEK and GIS can be synergistically integrated, this study provides a replicable and adaptive model for strengthening indigenous forest governance, enhancing tenure security, and embedding cultural values within contemporary conservation frameworks.

Received: 01 July 2025 / Accepted: 13 September 2025 / Available online: 20 September 2025

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Abstract

The aim of this study was to establish whether there are common peculiarities of root structure and ectomycorrhizas for two deciduous tree species growing on fly ash - artificial substrate with specific properties. The research was conducted in the southern taiga subzone of the Middle Urals at two ash dumps and typical zonal habitat. The roots of Betula pendula Roth and Populus tremula L. were studied. The following parameters were analysed: (i) soil concentrations of carbon (C), nitrogen (N), and phosphorus (P); (ii) micromorphological structure of fine roots and ectomycorrhizas; (iii) content of C and N in fine roots. The soils of ash dumps contained low amounts of N and high amounts of P compared with zonal soils. No species-specific features of fine root structure were detected for B. pendula and P. tremula. The size of roots, their vitality, the ratio of non-mycorrhizal and ectomycorrhizal roots, as well as the content and ratio of C and N did not differ between the trees of ash dumps and control area. Differences in the root structure between growing at ash dumps and in natural habitat B. pendula and P. tremula were generally low and affected only the features characterizing the size of the fungal mantle in ectomycorrhizas. The thickness of the mantle and its proportion in the total volume of ectomycorrhizae were less on the ash dumps than in the control habitat. Thus, the adaptation of the absorptive apparatus of B. pendula and P. tremula when living on fly ash occurs not due to autonomous rearrangements carried out by the plants, but probably by regulating the development of fungal symbionts.

Received: 15 June 2025 / Accepted: 29 August 2025 / Available online: 20 September 2025

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Abstract

Litterfall plays a crucial role in transferring nutrients from vegetation to soil, particularly in the carbon and nitrogen cycles. This study aims to estimate and compare the carbon stock in it from dominant tree species in 15-year-old fallow land. Litterfall traps measuring 1 × 1 m were placed beneath the stands of dominant tree species Pometia pinnata J.R.Forst. & G.Forst., Dracontomelon dao (Blanco) Merr. & Rolfe, and Octomeles sumatrana Miq., with three replicates. Carbon stock was calculated using the drying method to achieve constant litterfall weight. The stock of carbon measurement data were analysed using one-way ANOVA, followed by the Least Significant Difference (LSD) test at a p level <0.05. A significant difference was found in mean weekly carbon stock in litterfall between P. pinnata (11.33 ±7.8 g·m-2·week-1) and D. dao (19.50 ±8.8 g·m-2·week-1) and O. sumatrana (18.85 ±7.1 g·m-2·week-1), but D. dao and O. sumatrana did not differ significantly. The difference in carbon stock production is due to peak leaf shedding of D. dao and O. sumatrana during the study period, whereas P. pinnata was not shedding leaves, leading to its lowest carbon stock production. Additionally, canopy height may influence litterfall capture in the trap. Estimates of annual carbon stock in it showed high values: 5.73 t·ha-1·yr-1 for P. pinnata, 9.89 t·ha-1·yr-1 for D. dao, and 9.37 t·ha-1·yr-1 for O. sumatrana. Fallow land in Womnowi Village, Manokwari after 15 years, makes a substantial contribution to carbon stock. From the perspective of soil fertility for agricultural land, high carbon stock suggests that fallow land can be reutilised for agricultural purposes.

Received: 30 June 2025 / Accepted: 15 August 2025 / Available online: 22 August 2025

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Abstract

This study investigates variations of two main phenological events of European beech (Fagus sylvatica L.) across geographical gradients in its range in Bulgaria between 2017 and 2023. We found that altitude is the primary driver of leaf unfolding date, which is delayed by approximately 2.52 days per 100 m of elevation gain. In contrast, leaf colouring date is less influenced by altitude and more strongly driven by latitude, with a delay of about 2.12 days per degree northward. Leaf colouring date appeared more abrupt and latitude-dependent, likely due to regional climate differences in separate mountains. A modest influence of longitude on phenology was also detected, possibly linked to changes in continental climatic conditions in the west-east direction. These findings contribute to understanding how complex of geographic gradients shape the timing of phenological events and duration of vegetation period in European beech under the current climate
in Bulgaria. They could be used as a basis for impact forecasting of future climate scenarios in the south-eastern part of the distribution of European beech forests.

Received: 13 May 2025 / Accepted: 05 July 2025 / Available online: 18 August 2025

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