• Energy Research

There is an ongoing debate about the potential of localized conservation efforts to address the ecological challenges brought about by global climate shifts. Among these challenges, biological invasion negatively affects ecosystem health and biodiversity. In this study, we assessed the potential impact of global climate changes and human activities on the spread of the invasive species Broussonetia papyrifera in Pakistan's subtropical region. Jackknife analysis indicated that, among the climatic variables studied, the maximum temperature of the warmest month (bio05) made the most significant contribution, accounting for 25.6 % of the model's predictive capacity. Potential highly invaded regions are located in the territory of Islamabad, Rawalpindi, Attock, Nowshera, Swabi, Haripur, and Mardan. Some patches were also found to be invaded in Khyber Pakhtunkhwa (Abbottabad, Buner, Tor Ghar, and Peshawar) and Punjab (Narowal, Sialkot, Gujrat, Jhelum, and Chakwal). Specifically, based on all four Shared Socioeconomic Pathways (SSPs) scenarios for the 2050 s and 2070 s, the highly invaded regions of B. papyrifera are predicted to shift Northern Punjab, Eastern Khyber Pakhtunkhwa, and Northern Kashmir. Based on the SSPs 245 and 585 scenarios, the majority of highly invaded regions are projected to expand by 2050. Similarly, within these regions, the potentially invaded land area is estimated to increase to 2.74 % under SSPs 585 in the 2050 s, 5.29 % under SSPs 245 in the 2070 s, and 6.27 % under SSPs 585 in the 2070 s. Applying circuit theory and ecological resistance, a surface connectivity map of the species revealed that Rawalpindi and Sargodha in Punjab had the most prominent corridors, with rates being highest where ecological patches continually merged. This study is the first to predict B. papyrifera distribution in Pakistan under current and future climate change scenarios. Implementing nationwide guidelines comprehensively may curb the spread of invasive species and protect native plant diversity from extinction. The findings of this study will aid in timely monitoring and surveillance of B. papyrifera and in formulating integrated management plans at the national level to prevent its invasion, spread, and potential harm to newly projected regions.

Horse-chestnut (Aesculus hippocastanum L.) is an endemic and relict species from the Mediterranean biodiversity hotspot and a popular ornamental tree. Knowledge about the evolutionary history of this species remains scarce. Here, we ask what historical and ecological factors shaped the pattern of genetic diversity and differentiation of this species. We genotyped 717 individuals from nine natural populations using microsatellite markers. The influence of distance, topography and habitat variables on spatial genetic structure was tested within the approaches of isolation-by-distance and isolation-by-ecology. Species niche modeling was used to project the species theoretical range through time and space. The species showed high genetic diversity and moderate differentiation for which topography, progressive range contraction through the species' history and long-term persistence in stable climatic refugia are likely responsible. A strong geographic component was revealed among five genetic clusters that are connected with very limited gene flow. The environmental variables were a significant factor in the spatial genetic structure. Modeling results indicated that future reduction of the species range may affect its survival. The possible impact of climate changes and high need of in situ conservation are discussed.

AbstractThe wild relatives of cultivated apples would be an ideal source of diversity for breeding new varieties, which could potentially grow in diverse habitats shaped by climate change. However, there is still a lack of knowledge about the potential distribution of these species. The aim of the presented work was the understand the impacts of climate change on the potential distribution and habitat fragmentation of Caucasian crab apple (Malus orientalis Uglitzk.) and the designation of areas of high interest according to climatic conditions. We used the MaxEnt models and Morphological-Spatial Analysis (MSPA) to evaluate the potential distribution, suitability changes, habitat fragmentation, and connectivity throughout the species range in Turkey, Armenia, Georgia, Russia, and Iran. The results revealed that the potentially suitable range of M. orientalis encompasses 858,877 km², 635,279 km² and 456,795 km² under the present, RCP4.5 and RCP8.5 scenario, respectively. The range fragmentation analysis demonstrated a notable shift in the edge/core ratio, which increased from 50.95% in the current scenario to even 67.70% in the future. The northern part of the range (Armenia, northern Georgia, southern Russia), as well as the central and western parts of Hyrcania will be a core of the species range with suitable habitats and a high connectivity between M. orientalis populations and could work as major refugia for the studied species. However, in the Zagros and central Turkey, the potential range will shrink due to the lack of suitable climatic conditions, and the edge/core ratio will grow. In the southern part of the range, a decline of M. orientalis habitats is expected due to changing climatic conditions. The future outlook suggests that the Hyrcanian forest and the Caucasus region could serve as important refuges for M. orientalis. This study helps to understand spatial changes in species’ range in response to climate change and can help develop conservation strategies. This is all the more important given the species’ potential use in future breeding programs aimed at enriching the gene pool of cultivated apple varieties.

Aesculus hippocastanum is a well-known species, which is popular because of its ornamental value. However, data on the demographic structure and potential distribution of A. hippocastanum are limited. The invasion of Cameraria ohridella into Europe has harmed those trees growing in artificial sites, but the presence of this insect in natural stands has been little studied. Here we aimed to investigate the demographic structure infestation level of natural populations of horse-chestnut. Additionally, Maxent modelling was used to predict the potential range of A. hippocastanum, based on the localities available in the literature. Field data analysis indicated that natural populations of A. hippocastanum are mostly found nearby mountain streams. The populations showed a diverse height structure and large numbers of seedlings, which indicate high population dynamics. The level of infestation by C. ohridella varied greatly and correlated with altitude. Secondary infestation might explain this infestation variability in some natural populations. Other hypotheses, such as environmental resistance factors or different genetic variability, are also discussed. By spatial distribution modelling, we found that the precipitation of the coldest and warmest quarters, as well as altitude, are important factors influencing the potential distribution of A. hippocastanum.

AbstractScots pine is one of the most widely occurring pines, but future projections suggest a large reduction in its range, mostly at the southern European limits. A significant part of its range is located in the Caucasus, a global hot-spot of diversity. Pine forests are an important reservoir of biodiversity and endemism in this region. We explored demographic and biogeographical processes that shaped the genetic diversity of Scots pine in the Caucasus ecoregion and its probable future distribution under different climate scenarios. We found that the high genetic variability of the Caucasian populations mirrors a complex glacial and postglacial history that had a unique evolutionary trajectory compared to the main range in Europe. Scots pine currently grows under a broad spectrum of climatic conditions in the Caucasus, which implies high adaptive potential in the past. However, the current genetic resources of Scots pine are under high pressure from climate change. From our predictions, over 90% of the current distribution of Scots pine may be lost in this century. By threatening the stability of the forest ecosystems, this would dramatically affect the biodiversity of the Caucasus hot-spot.

Juniperus drupacea is a unique relict species found in the mountains of southern Greece, southern Turkey, and western Syria and Lebanon. The aim of this study was to describe the natural range of this juniper by determining the current locations of its populations and to predict a theoretical range for the species based on current, past, and future climatic conditions. We used data from the literature, herbarium materials, and our unpublished field notes (about 500 georeferenced points in total) to determine the current natural distribution of J. drupacea (realized niche). To predict suitable conditions with the program MaxEnt, we used data from the WordClim database, which allowed estimation of the potential niche. The potential niche of J. drupacea was much wider during the Last Glacial Maximum (LGM) and was severely restricted during the Eemian interglacial period. Depending on the climate scenario, this species could become endangered in the future due to climate changes. Considering the relatively restricted geographic range of J. drupacea and the decreasing numbers of localities where it is found, conservation strategies should be adopted to allow for preservation of its genetic and morphological diversity. The study was financially supported by the Institute of Dendrology of the Polish Academy of Sciences, Kórnik, Poland, and by the Polish Ministry of Science under grant no. NN303153037.

AbstractCupressus atlantica is a narrow endemic species of semi-arid and sub-humid habitats in the western High Atlas, Morocco. We explored the possible dynamics of the species’ range under climatic changes using species distribution modelling (SDM) to identify populations vulnerable to range changes. Additionally, we investigated the spatial genetic structure (SGS), the effective population size and genetic connectivity in natural populations, which may provide important data on demo-genetic processes and support the conservation management of this critically endangered species. The SDM results showed that the current species range constitutes only 49% of the potential distribution. Under the most pessimistic scenarios (RCP6.0 and RCP8.5), a significant reduction in the species range was predicted. However, the projection based on RPC4.5 revealed possible extensions of the habitats suitable for C. atlantica. Potentially, these areas could serve as new habitats that could be used with the assisted migration approach aiming to mitigate the current fragmentation. In terms of the SGS, significant and positive aggregation of relatives was detected up to ca. 100 m. In comparison to other fragmented and endemic species, the detected SGS was weak (Sp = 0.0112). The estimated level of recent gene flow was considerable, which likely prevented a strong SGS and allowed diversity to accumulate (HE = 0.894). The most alarming results concern the effective population size, which was very low in the studied populations (< 53), suggesting a possible increase in inbreeding and loss of diversity in the near future. More effective conservation actions integrating in situ and ex situ measures should be undertaken to prevent extirpation of the species.