Ministry of Environment and Water

In the coming decades, Bulgaria is expected to be affected by higher air temperatures and decreased precipitation, which will significantly increase the risk of droughts, forest ecosystem degradation and loss of ecosystem services (ES). Drought in terrestrial ecosystems is characterized by reduced water storage in soil and vegetation, affecting the function of landscapes and the ES they provide. An interdisciplinary assessment is required for an accurate evaluation of drought impact. In this study, we introduce an innovative, experimental methodology, incorporating remote sensing methods and a system approach to evaluate vegetation drought stress in complex systems (landscapes and ecosystems) which are influenced by various factors. The elevation and land cover type are key climate-forming factors which significantly impact the ecosystem’s and vegetation’s response to drought. Their influence cannot be sufficiently gauged by a traditional remote sensing-based drought index. Therefore, based on differences between the spectral reflectance of the individual natural land cover types, in a near-optimal vegetation state and divided by elevation, we assigned coefficients for normalization. The coefficients for normalization by elevation and land cover type were introduced in order to facilitate the comparison of the drought stress effect on the ecosystems throughout a heterogeneous territory. The obtained drought coefficient (DC) shows patterns of temporal, spatial, and interspecific differences on the response of vegetation to drought stress. The accuracy of the methodology is examined by field measurements of spectral reflectance, statistical analysis and validation methods using spectral reflectance profiles.

Abstract Background: Enterocytozoon hepatopenaei (EHP) is an enteric pathogen that affects Penaeus vannamei and Penaeus monodon shrimp in many SE Asian countries. In the western hemisphere, EHP was reported for the first time in 2016 in farmed P. vannamei in Venezuela. Anecdotal evidence suggests that EHP is more prevalent in grow-out ponds where the salinity is high (>15 parts per thousand (ppt)) compared to grow-out ponds with low salinities (<5 ppt). Considering that P. vannamei is an euryhaline species, we were interested in knowing if EHP can propagate in P. vannamei in low salinities. Results: In this study, we described an experimental infection using fecal strings as a source inoculum. Specific Pathogen Free (SPF) P. vannamei were maintained at three different salinities (2 ppt, 15 ppt, and 30 ppt) while continuously challenged using feces from known EHP-infected P. vannamei over a period of three weeks. The fecal strings, used as a source of EHP inocula in the challenges, was sufficient to elicit an infection in shrimp maintained at the three salinities. The infectivity of EHP in shrimp reared at 2 ppt, 15 ppt, and 30 ppt salinities was confirmed by PCR and histopathology. The prevalence and the severity of the EHP infection was higher at 30 ppt than at 2 ppt and 15 ppt. Conclusion: The data suggests that fecal strings are a reliable source of EHP inoculum to conduct experimental challenges via the fecal-oral route. An EHP infection can occur at a salinity as low as 2 ppt, however, the prevalence and the severity of the EHP infection is higher at a salinity of 30 ppt.

Groundwater is the main source of irrigation in the northeastern part of the United Arab Emirates (UAE). The excess use of groundwater for irrigation has decreased groundwater flow by almost one tenth. Due to the strategic importance of water resources in the region, and considering the complexity of the aquifer system, the main objective of this paper is to establish an accurate groundwater budget in order to assess water availability in this area. Results show that the current extraction rates are not sustainable and need to be reduced to mitigate the present severe groundwater depletion and to achieve sustainable development in the area.

The Roach’s mouse-tailed dormouse ( Myomimus roachi ) is an endangered mammal in Europe with poorly known distribution and biology in Bulgaria. Cranial remains of 15 specimens were determined among 30532 mammals in Barn Owl ( Tyto alba ) pellets in 35 localities from 2000 to 2008 and 32941 mammals in Eagle Owl ( Bubo bubo ) pellets in 59 localities from 1988 to 2011 in SE Bulgaria. This dormouse was present with single specimens in 11 localities and whit 4 specimens in one locality. It is one of the rarest mammals in the region that forms only up to 1% by number of mammalian prey in the more numerous pellet samples. The existing protected areas ecological network covers six out of 15 (40%) localities where the species has been detected in the last two decades. We discuss the necessity of designation of new Natura 2000 zones for the protection of the Roach’s mouse-tailed dormouse in Bulgaria.

Pollen analysis was performed on a 343 cm long core recovered from Lake Ribno Banderishko (2190 m) on Northern Pirin Mountain (southwestern Bulgaria), supplemented by six '4C AMS dates. The lower part of the sequence (343-290 cm) was deposited during the Lateglacial when mountain-steppe vegetation with Artemnisia, Poaceae, Chenopodiaceae and other herbs, and with stands of Pinus and Juniperus, dominated at high altitudes. The identification of pollen of mesophilous trees suggests that local populations may have survived in refuges below 1000 m where environmental conditions were favourable for their growth. The reforestation dynamics in early-Holocene times (11200-8400 cal. BP) started with Betula forests at high altitudes and deciduous forests with Quercus, Ulmus, Tilia and Fraxinus excelsior at lower altitudes. The time of the maximal spread of Corylus at c. 8000 cal. BP coincided with the establishment of Abies alba in the forests, and the beginning of the formation of a coniferous belt, dominated by pines (Pinus sylvestris, P. peuce, P. nigra and P. heldreichii). The late immigrants Fagus sylvatica and Picea abies invaded the mountain slopes at c. 4400 cal. BP and 3300 cal. BP, respectively. Palynological traces of anthropogenic activity and landscape management began after c. 2200 cal. BP.

In the frame of activities under EMEP programme emissions of sulphur, lead and benzo(a)pyrene were evaluated and presented in 25x25 km set for the reference years 1990 and 1995. The data on emissions are submitted by the Bulgarian Ministry of Environment and Waters (MoEW), based on economic statistics and CORINAIR methods. At first SNAP-90 was used, but for more recent estimates SNAP-94 was applied. Emissions are presented in two categories - large point sources (LPS) and area sources. According to the definition of LPS in CORINAIR thirtry four LPS of sulphur are identified in the country with yearly emissions in the range 63 — 222500 Mg S/y. For lead the number of LPS is 20 (0.1-19.8 Mg Pb/y) and for B(a)P - 13 LPS (1-651 kg B(a)P/y..