Prespa bears know no bounds: Using genetics to estimate brown bear abundance in Prespa

Estimating the abundance of brown bears in the wild is a daunting task. It’s virtually impossible to directly observe the bears and estimate their abundance. Tagging them with individual specific tags is highly demanding and unfeasible in any real-life setting, as is reading of such tags. That is why, in many cases the abundance estimates of brown bear populations are still based on expert opinions and rarely backed by any defensible data. These so-called guesstimates are in many instances followed by the often-justified skepticism in their validity. Luckily, the possibilities opened up considerably with the rise of molecular genetics, which uses state-of-the-art methods that allow individual “tagging” of bears through genotypes obtained from genetic material that they left in the environment, like feces or hair.

Following the aforementioned natural progression of research, previous efforts to estimate the size of the population in Prespa (Stojanov et al. 2012) used questionnaire surveys to guesstimate the population number of the brown bear in the wider Prespa region to be around 60, of those 35 in Macedonian Prespa, 18 in Greek Prespa and 7 in Albanian Prespa.

This led to the idea of conducting a two-year transboundary study in Prespa using novel genetic techniques to estimate the abundance of brown bears in the region, as part of the project “Strengthening NGO-led Conservation in the Transboundary Prespa Basin”, implemented by the PrespaNet NGO network.  The broader scope of the study was to estimate the dietary habits and habitat use of the brown bear through scat collection, while using the fresh samples to genotype the individuals. The sampling was conducted in all three range countries and the samples were sent to genetic experts from Ljubljana who performed the next-generation sequencing. Besides estimating the brown bear abundance in the area, the secondary goal was also to get some insight on the genetic diversity of these bears.

The genetic study revealed a minimum of 51 individuals, 19 females and 32 males in the entire study area, which is well within the expectations and in accordance with the previous guesstimates. Genetic diversity in bears in the Prespa Region seems somewhat lower than that observed in the west Balkans, but considerably higher than in the European bear populations that are known to be very small and endangered. This fits with the findings of other studies in that wider geographic region.

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Geographic distribution of collected samples with lines connecting samples of the same animal.

Recaptures enable the possibility of connecting the sampling locations of the same individual, giving insight into their movement and use of corridors (see photo). While this study did not achieve a detailed mark-recapture estimate of bear abundance in the area due to the somewhat poor quality of the samples, it did manage to produce some preliminary results of spatial patterns of bears in the region. Notably, some of the bears cross the borders between the countries, with two male individuals observed to make longer excursions throughout the study area. Results like these highlight the importance of good habitat connectivity and the use of bears as flagship species to enforce a better protection of biodiversity hotspots such as Prespa.

This study is the first of its type in the region, and the results, even though not exceptional, were perfectly acceptable for a pilot study. This allows for considerable optimism if a similar or larger study would be repeated and, considering all the field know-how and experience that was gained by the project partners, we firmly believe that a highly successful study of brown bear population size and distribution could be done in the area in the future.

You can read more about these and other interesting findings of the study in the full report on the following link.

‘Habitat types’

They are a part of our planet’s incredible biodiversity, and they include the places, or ‘habitats’, that are home to all life on Earth.

Read more about the habitat types of transboundary Prespa, or visit some of them using the guide in this electronic version of our new leaflet, which has been created as part of the PrespaNet project ‘Strengthening NGO-led Conservation in the Transboundary Prespa Basin’, funded by PONT and the Aage V. Jensen Charity Foundation, with support from EuroNatur, and which will be available in print form soon!

Pilot alder restoration

The mapping of Prespa littoral habitats, conducted in 2018 resulted with scientifically sound recommendations on their management. According to the habitats map, priority habitats, Alluvial alder forests together with wet meadows were identified as a priority for restoration and management, respectively. 

The habitat selected for revitalization-Riparian forest with Alnus glutionosa, is a priority habitat type according to the Habitat Directive 92/43/EEC. The common alder not only in NP Ezerani, but also along the entire shore of Prespa Lake is presented with small forest patches, scattered through different types of vegetation. Given the biodiversity and the importance of different vegetation types i.e., the presence of important habitat types all over Prespa, it is very difficult to choose the most suitable place for reforestation, and it is crucial to take into account the importance of the surrounding habitats and types of vegetation. 

The process of selecting the most suitable plot for reforestation included analysis of a number of parameters, but also a number of filed visits to determine the true condition of the potential plots. The hydrology, morphology, pedology of the area, as well as the land ownership were taken into account. The results were presented in a summary map with possible places for revitalization. All identified plots were further ranked through their prioritization. For this purpose, the funnel method was used, through which, by applying different exclusion and selection criteria, it gave the most potential reforestation area. The highest scoring plots were singled out as the most suitable one.

The process of revitalization and restoration of alder forests is a complex process and includes a series of follow-up activities which determine its success, that MES undertook: 

  • Research on the suitability for revitalization of a given area,
  • Favorable and appropriate weather conditions for each of the activities (seed collection, production of planting material, field preparation, afforestation, etc.),
  • Providing seed material for afforestation,
  • Appropriate treatment of the seed material,
  • Human resources and equipment (nurseries, manual workers, mowing equipment, ploughing, digging, watering, protection and care of seedlings, electronic equipment for monitoring seedlings),
  • Preparation of the terrain for revitalization and providing water source for watering the seedlings (mowing, removal of other shrubs and weeds, digging, channelling the nearest waters).

After the finalization of all the preparation activities, one part of the selected plot was sown with alder seeds and another part was planted with 45 one-year and two-year old shoots, that were collected previously near the area of reforestation. The Ezerani Nature Park followed closely and was involved in all the activities, as they will continue to monitor the growth and the development of the seedling in the next period. The reforestation process will continue in the following years.

Pilot wet-meadow management activities

The mapping of Prespa littoral habitats, conducted in 2018 resulted with scientifically sound recommendations on their management. According to the habitats map, priority habitats – Alluvial alder forests together with wet meadows were identified as a priority for restoration, i.e., management. 

In 2019, MES team started with pilot management activities of wet meadows around Prespa Lake. First, it was determined their distribution along the Prespa shoreline with a total area of ​​547 ha. The habitat map revealed four different types of wet meadows in the Macedonian part of Prespa:

  1. Mediterranean tall humid herb grasslands of the Molinio-Holoschoenion
  2. Beds of large Carex spp.
  3. Calamagrostis epigejos communities
  4. Helleno-Moesian riverine and humid Trifolium meadows

In order to confirm the socio-economic, as well as the cultural significance of the wet meadows, private owners (of wet meadows) survey was conducted. Target groups were stockbreeders and owners of larger areas under meadows. The results showed that 44% mow their meadows, which satisfies the complete diet for their livestock, and 56% don’t, as they don’t have the necessity. Also, short-term biodiversity research was conducted, which revealed three new species of spiders for North Macedonia (Pisaura noviciaBerlandina cinerea and Trachelas minor, a representative of a spider family encountered for the first time, nationally, Trachelidae) and three new species of grasshoppers for Prespa, but also huge negative differences in the species diversity of the meadows exposed to agricultural practices in the region. The recommendations that emerged from the results obtained from the activities in 2019 gave several directions for improving the condition of this habitat. Among other things, a pilot project was proposed – stimulate summer mowing of wet meadows, remove the hay (biomass), and distribute it to local farmers to use. 

In order to select the most suitable plot for management, a system of criteria was created:

  1. to be within the Ezerani Nature Park
  2. to be outside of the strict protection zone
  3. to be state-owned
  4. to be spatially distributed as a buffer zone between orchards and natural habitats in ENP
  5. to be larger than 2 hectares
  6. to be easily accessible 

In the process of selection, MES was in constant communication with the Municipality of Resen. Various working meetings and field visits to the area were organized in order to finalize the selection. After the plot was selected, a local farmer was hired to process the land and bale the hay. 

An area of 16.054m2  was mowed in August, 11.858 m2 consisting of the Calamagrostis epigejos community and 4.196mbelonging to beds of large Carex spp. The mowed hay was collected into 350 bales that in collaboration with Municipality of Resen were distributed to local stockbreeders without financial compensation, which was another way to help the local community benefit from habitat restoration activities. 

Biodiversity day 22.05.2020

Despite the pandemic, MES managed to mark this incredibly important day following all measures of precaution. Together with otu parners from Greece (SPP) and Albania (PPNEA) we counted the Dalmatian and Great White Pelican pairs on Lesser and Greater Prespa Lakes. We moved along predefined points of interest and on the way met with our collaborators from Nature Park “Ezerani”, and several activists and volunteers from the region that helped us finally and timely reach our last destination, one of the most special places in our country – Golem Grad island. The whole experience was documented using facebook live and you can see the video in English here as well as videos of us approaching and circling the island. For more videos with Macedonian content please visit the Macedonian version of this post and also enjoy the photographs.

Saying hi to our international colleagues and followers from v. Konjsko

Approaching Golem Grad Island

Riding around the island

A message from our friends and colleagues from National Park “Galichica”

Newt mointoring with NP Galichica

MES and NP Galichica started a detailed monitoring scheme (using the capture-mark-recapture methodology) of the Macedonian newt (Triturus macedonicus) in Simoncheska Pond on Mt. Galichica. During two capture sessions we used aquatic funnel traps to trap newts and photographed the unique belly color patterns of each captured individual in order to recognize recaptures. This efficient and reliable methodology of estimating newt population size was implemented for the first time in North Macedonia and is another testament to the fruitful collaboration between MES and NP Galichica. Practicing such standardized methodology is crucial to North Macedonia’s European Union aspirations. Namely, the Macedonian newt is on Annex II of the EU habitats directive, which means that its presence qualifies the area for a protected NATURA 2000 site and its populations should be monitored continuously.