Identifying potential areas of expansion for the endangered brown bear (Ursus arctos) population in the Cantabrian Mountains (NW Spain)

Spatio-temporal shifts in British wild bees in response to changing climate

Climate plays a major role in determining where species occur, and when they are active throughout the year. In the face of a changing climate, many species are shifting their ranges poleward. Many species are also shifting their emergence phenology. Wild bees in Great Britain are susceptible to changes in climatic conditions but little is known about historic or potential future spatio-temporal trends of many species. This study utilized a sliding window approach to assess the impacts of climate on bee emergence dates, estimating the best temperature window for predicting emergence dates for 88 species of wild bees. Using a 'middle-of-the-road' (RCP 4.5) and 'worst-case' (RCP 8.5) climate scenario for the period 2070-2079, predictions of future emergence dates were made. In general, the best predicting climate window occurred in the 0-3 months preceding emergence. Across the 40 species that showed a shift in emergence dates in response to a climate window, the mean advance was 13.4 days under RCP 4.5 and 24.9 days under RCP 8.5. Species distribution models (SDMs) were used to predict suitable climate envelopes under historic (1980-1989), current (2010-2019) and future (2070-2079 under RCP 4.5 and RCP 8.5 scenarios) climate conditions. These models predict that the climate envelope for 92% of studied species has increased since the 1980s, and for 97% and 93% of species under RCP 4.5 and RCP 8.5 respectively, this is predicted to continue, due to extension of the northern range boundary. While any range changes will be moderated by habitat availability, it highlights that Great Britain will likely experience northward shifts of bee populations in the future. By combining spatial and temporal trends, this work provides an important step towards informing conservation measures suitable for future climates, directing how interventions can be provided in the right place at the right time.

Role of paleoclimatic and paleohydrological processes in lineage divergence in freshwater organisms: A snippet from lentic genus Pila

The Indian subcontinent is extremely diverse in terms of its flora and fauna. However, only a handful of studies have aimed to understand the diversity of freshwater invertebrates using multiple lines of evidence in recent times. Here we aimed to estimate the cryptic diversity of two widespread freshwater snail species within the genus Pila (Röding, 1798) and uncover the processes behind lineage diversification in these species. We sequenced mitochondrial and nuclear markers from a comprehensive sampling of specimens from different river basins in India. We implemented an integrative taxonomy approach to delimit the lineages in these groups, employing phylogenetic, geometric morphometric and niche modelling-based methods. Then, we investigated the drivers of lineage divergence in these species using population genetic tools in conjunction with divergence time estimation. We found that both species consist of several genetically and ecologically distinct lineages. The genetic data showed that several of these lineages are restricted to a single or a few river basins. The divergence time estimation analyses indicated that the time frame of divergence within the species coincided with paleohydrological and paleoclimatic events in the Miocene. The diversification was primarily driven by allopatric isolation into different river basins. To conclude, the study sheds light on the complex interaction between the habitat preference of the species and the environment in shaping the diversification patterns in this group.

Prediction of global potential suitable habitats of Nicotiana alata Link et Otto based on MaxEnt model

Nicotiana alata Link et Otto, widely used in landscaping, is not only of great ornamental value but also of high commercial and medical value. The global potential habitat of N. alata and the environmental factors affecting its distribution are not that clear at present. To provide a reference for the reasonable and extensive planting of N. alata now and in the future, the MaxEnt model was used to predict its global suitable habitats under current and future climate conditions, respectively, based on global geographic distribution data of N. alata and the current and future world bioclimatic variables. The results showed that mean temperature of the driest quarter (bio9), precipitation of driest month (bio14), precipitation seasonality (bio15) and max temperature of warmest month (bio5), were the key bioclimatic variables governing the distribution of N. alata. The global suitable habitats of N. alata were mainly distributed in Europe, the United States, southeastern South America, and China under current climate conditions. Compared with current climate conditions, the future climate decreased suitable habitats of N. alata under SSP1-2.6, and SSP2-4.5 scenario and increased suitable habitats of N. alata under SSP3-7.0, and SSP5-8.5 climatic scenarios. The results provided valuable information and theoretical reference for the reasonable planting of N. alata.

Modeling climate change impacts on the distribution of an endangered brown bear population in its critical habitat in Iran

Climate change is one of the major challenges to the current conservation of biodiversity. Here, by using the brown bear, Ursus arctos, in the southernmost limit of its global distribution as a model species, we assessed the impact of climate change on the species distribution in western Iran. The mountainous forests of Iran are inhabited by small and isolated populations of brown bears that are prone to extinction in the near future. We modeled the potential impact of climate change on brown bear distribution and habitat connectivity by the years 2050 and 2070 under four representative concentration pathways (RCPs) of two general circulation models (GCMs): BCC-CSM1-1 and MRI-CGCM3. Our projections revealed that the current species' range, which encompasses 6749.8 km² (40.8%) of the landscape, will decline by 10% (2050: RCP2.6, MRI-CGCM3) to 45% (2070: RCP8.5, BCC-CSM1-1). About 1850 km² (27.4%) of the current range is covered by a network of conservation (CAs) and no-hunting (NHAs) areas which are predicted to decline by 0.64% (2050: RCP2.6, MRI-CGCM3) to 15.56% (2070: RCP8.5, BCC-CSM1-1) due to climate change. The loss of suitable habitats falling within the network of CAs and NHAs is a conservation challenge for brown bears because it may lead to bears moving outside the CAs and NHAs and result in subsequent increases in the levels of bear-human conflict. Thus, re-evaluation of the network of CAs and NHAs, establishing more protected areas in suitable landscapes, and conserving vital linkages between habitat patches under future climate change scenarios are crucial strategies to conserve and manage endangered populations of the brown bear.

Patterns of Human–Brown Bear Conflict in the Urban Area of Brașov, Romania

Human–bear conflicts are increasing in number due to deforestation, urban expansion, tourism, and habitat invasion by humans. Our study was conducted in Brașov, a picturesque city in central Romania. Brașov is surrounded by forests and has significant tourist traffic, but also much uncollected garbage and many garbage containers, which attract brown bears. We recorded human–bear conflicts in four districts (Răcădău, the Historic Centre, Noua, and Gară) between 2004 and 2018, finding 55 cases in total, of which in 19 cases involving people, 4 people were killed and 32 were injured. In 36 cases, there were no human victims. We mapped the locations of human–bear conflicts and garbage containers, then analysed their space–time location and human victims in terms of behavioural factors. The altitudes at which brown bears were identified ranged from 580 to 790 m, whereas bears were found in the city at distances of between 100 and 2600 m from the forest. The highest frequency of human–bear conflicts occurred during summer and autumn, and the most common behavioural factor was human outdoor activities. This study provides an important background for understanding human–bear conflicts and will help local authorities develop effective strategies to reduce human–bear conflicts and mitigate risk.

Habitat characteristics around dens in female brown bears with cubs are density dependent

The mechanisms determining habitat use in animal populations have important implications for population dynamics, conservation, and management. Here, we investigated how an increase in annual numbers of brown bear females with cubs of the year (FCOY) in a growing, yet threatened population, could explain differences in the habitat characteristics around reproductive dens. Habitat characteristics around FCOY dens were compared between a low bear density period (1995–2005) and a period when the population was increasing (2006–2016). We also compared the distance to the nearest breeding area and to all other breeding areas observed during the same year. The results suggested that during the second period, breeding areas were closer to rivers, fruit trees, and anthropogenic sources of disturbance (trails, highways) than in 1995–2005. There were also shorter distances to the closest neighboring breeding area, while the mean distance among FCOY breeding areas increased as the population grew and expanded at the landscape level. These changes may reflect that the best den locations were increasingly occupied (i.e., ideal-despotic distribution), and may be further explained by the avoidance of conspecifics by FCOY in a critical time of the year, when newborn cubs are most vulnerable. We suggest that both density-dependent factors and human-related features of the landscape are crucial to understanding long-term dynamics in the habitat use of a threatened species.

Prediction of the potential geographical distribution of Betula platyphylla Suk. in China under climate change scenarios

Climate is a dominant factor affecting the potential geographical distribution of species. Understanding the impact of climate change on the potential geographic distribution of species, which is of great significance to the exploitation, utilization, and protection of resources, as well as ecologically sustainable development. Betula platyphylla Suk. is one of the most widely distributed temperate deciduous tree species in East Asia and has important economic and ecological value. Based on 231 species distribution data points of Betula platyphylla Suk. in China and 37 bioclimatic, soil, and topography variables (with correlation coefficients < 0.75), the potential geographical distribution pattern of Betula platyphylla Suk. under Representative Concentration Pathway (RCP) climate change scenarios at present and in the 2050s and 2070s was predicted using the MaxEnt model. We analyzed the main environmental variables affecting the distribution and change of suitable areas and compared the scope and change of suitable areas under different climate scenarios. This study found: (1) At present, the main suitable area for Betula platyphylla Suk. extends from northeastern to southwestern China, with the periphery area showing fragmented distribution. (2) Annual precipitation, precipitation of the warmest quarter, mean temperature of the warmest quarter, annual mean temperature, and precipitation of the driest month are the dominant environmental variables that affect the potential geographical distribution of Betula platyphylla Suk. (3) The suitable area for Betula platyphylla Suk. is expected to expand under global warming scenarios. In recent years, due to the impact of diseases and insect infestation, and environmental damage, the natural Betula platyphylla Suk. forest in China has gradually narrowed. This study accurately predicted the potential geographical distribution of Betula platyphylla Suk. under current and future climate change scenarios, which can provide the scientific basis for the cultivation, management, and sustainable utilization of Betula platyphylla Suk. resources.

Bottlenose Dolphins and Seabirds Distribution Analysis for the Identification of a Marine Biodiversity Hotspot in Agrigento Waters

The aim of this study is to evaluate the presence of biodiversity hotspots in Agrigento waters (Mediterranean Sea) to define the conservation area for bottlenose dolphins (Tursiops truncatus) and seabirds (Calonectris diomedea, Puffinus yelkouan, and Hydrobates pelagicus), according to European directives. With this purpose, the maximum entropy algorithm (MaxEnt) was applied to the sighting points of the focal species. They co-occur in the study area and have been documented to forage behind trawlers. In this study, a fishing rate was designed and used as an explanatory variable of the species distribution, together with physiographic variables. Data were collected during 68 surveys in the waters off Agrigento province. MaxEnt models showed a strong predictive power, with distance from the coast being the greatest predicting variable, followed by slope, depth, and fishing rate. For all the species considered, the probability of presence increased as the fishing rate grew. Cartographic analysis revealed one area shared by the species, which occupies 529 km2, from the shoreline to 100 m depth. This study increases knowledge on the distribution and habitat preferences of the target species in the Sicilian waters. Evaluating the influence of fisheries is a promising method that needs further testing to apply effective management measures.

Joining forces toward proactive elephant and rhinoceros conservation

Proactive approaches that anticipate the long-term effects of current and future conservation threats could increase the effectiveness and efficiency of biodiversity conservation. However, such approaches can be obstructed by a lack of knowledge of habitat requirements for wildlife. To aggregate and assess the suitability of current information available on habitat requirements needed for proactive conservation, we conducted a systematic review of the literature on elephant and rhinoceros habitat requirements and synthesized data by combining a vote counting assessment with bibliometric and term maps. We contextualized these numeric and terminological results with a narrative review. We mapped current methods, results, terminology, and collaborations of 693 studies. Quantitative evidence for factors that influence the suitability of an area for elephants and rhinoceros was biased toward African savanna elephants and ecological variables. Less than one third of holistic approaches considered equal amounts of ecological and anthropogenic variables in their assessments. There was a general lack of quantitative evidence for direct proxies of anthropogenic variables that were expected to play an important role based on qualitative evidence and policy documents. However, there was evidence for a segregation in conceptual frameworks among countries and species and between science versus policy literature. There was also evidence of unused potential for collaborations among southern hemisphere researchers. Our results indicated that the success of proactive conservation interventions can be increased if ecological and anthropogenic dimensions are integrated into holistic habitat assessments and holistic carrying capacities and quantitative evidence for anthropogenic variables is improved. To avoid wasting limited resources, it is necessary to form inclusive collaborations within and across networks of researchers studying different species across regional and continental borders and in the science-policy realm.

Seasonal and daily activity patterns of mammals in the colony of great cormorants

Despite extreme changes of ecosystems made by breeding colonies of great cormorants (Phalacrocorax carbo), these territories are still used by mammals. We present results of the analysis of mammal seasonal and daily activity patterns, registered by camera traps in two colonies of the great cormorants in Lithuania. Red foxes and raccoon dogs mainly visited colonies in the cormorant breeding time, April to July. In the inland colony of great cormorants in Lukštas Lake, average red fox relative shooting frequency in cormorant breeding time considerably exceeded that in non-breeding time (on average, 41.8 and 5.9 photos/100 days respectively). In the peninsular colony of great cormorants in Juodkrantė average relative shooting frequency of red fox in the breeding time was 7.8 versus 3.4 photos/100 days in non-breeding time, relative shooting frequencies of raccoon dog were 50.0 versus 1.3 photos/100 days, respectively. Daily activity patterns of wild boar and red fox in both colonies, as well as activity patterns of raccoon dog in Lukštas were related to the activity of cormorants with various degree of significance.

Rubbing behavior of European brown bears: factors affecting rub tree selectivity and density

Scent-mediated communication is considered the principal communication channel in many mammal species. Compared with visual and vocal communication, odors persist for a longer time, enabling individuals to interact without being in the same place at the same time. The brown bear (Ursus arctos), like other mammals, carries out chemical communication, for example, by means of scents deposited on marking (or rub) trees. In this study, we assessed rub tree selectivity of the brown bear in the predominantly deciduous forests of the Cantabrian Mountains (NW Spain). We first compared the characteristics of 101 brown bear rub trees with 263 control trees. We then analyzed the potential factors affecting the density of rub trees along 35 survey routes along footpaths. We hypothesized that: (1) bears would select particular trees, or tree species, with characteristics that make them more conspicuous; and (2) that bears would select trees located in areas with the highest presence of conspecifics, depending on the population density or the position of the trees within the species' range. We used linear models and generalized additive models to test these hypotheses. Our results showed that brown bears generally selected more conspicuous trees with a preference for birches (Betula spp.). This choice may facilitate the marking and/or detection of chemical signals and, therefore, the effectiveness of intraspecific communication. Conversely, the abundance of rub trees along footpaths did not seem to depend on the density of bear observations or their relative position within the population center or its border. Our results suggest that Cantabrian brown bears select trees based on their individual characteristics and their location, with no influence of characteristics of the bear population itself. Our findings can be used to locate target trees that could help in population monitoring.

Identifying priority core habitats and corridors for effective conservation of brown bears in Iran

Iran lies at the southernmost range limit of brown bears globally. Therefore, understanding the habitat associations and patterns of population connectivity for brown bears in Iran is relevant for the species’ conservation. We applied species distribution modeling to predict habitat suitability and connectivity modeling to identify population core areas and corridors. Our results showed that forest density, topographical roughness, NDVI and human footprint were the most influential variables in predicting brown bear distribution. The most crucial core areas and corridor networks for brown bear are concentrated in the Alborz and Zagros Mountains. These two core areas were predicted to be fragmented into a total of fifteen isolated patches if dispersal of brown bear across the landscape is limited to 50,000 cost units, and aggregates into two isolated habitat patches if the species is capable of dispersing 400,000 cost units. We found low overlap between corridors, and core habitats with protected areas, suggesting that the existing protected area network may not be adequate for the conservation of brown bear in Iran. Our results suggest that effective conservation of brown bears in Iran requires protection of both core habitats and the corridors between them, especially outside Iran’s network of protected areas.

Identifying Potentially Climatic Suitability Areas for Arma custos (Hemiptera: Pentatomidae) in China under Climate Change

Spodoptera frugiperda is a notorious pest that feeds on more than 80 crops, and has spread over 100 countries. Many biological agents have been employed to regulate it, such as Arma custos. A. custos is a polyphagous predatory heteropteran, which can effectively suppress several agricultural and forest pests. Thus, in order to understand where A. custos can survive and where can be released, MaxEnt was used to predict the potentially suitable areas for A. custos in China under climate change conditions. The results show that the annual mean temperature (bio1) and annual precipitation (bio12) are the major factors influencing the distribution of A. custos. The optimal range of the two are 7.5 to 15 °C, 750 to 1200 mm, respectively. The current climate is highly suitable for A. custos in Hebei, Henan, Shandong, Anhui, Hubei, Jiangsu, and Zhejiang Provinces. Considering the currently suitable distribution area of S. frugiperda, artificially reared A. custos is suitable for release in Fujian, Zhejiang, Jiangxi, Hunan, and southeastern Sichuan Provinces. Under the future climatic scenarios, the suitable area will decrease and shift towards the north. Overall, this result can provide a reference framework for future application of A. custos for biological control.

Coastal Pine-Oak Glacial Refugia in the Mediterranean Basin: A Biogeographic Approach Based on Charcoal Analysis and Spatial Modelling

During the glacial episodes of the Quaternary, European forests were restricted to small favourable spots, namely refugia, acting as biodiversity reservoirs. the Iberian, Italian and Balkan peninsulas have been considered as the main glacial refugia of trees in Europe. In this study, we estimate the composition of the last glacial forest in a coastal cave of the Cilento area (SW Italy) in seven time frames, spanning from the last Pleniglacial to the Late Glacial. Charcoal analyses were performed in seven archaeological layers. Furthermore, a paleoclimate modelling (Maxent) approach was used to complement the taxonomic identification of charcoal fragments to estimate the past potential distribution of tree species in Europe. Our results showed that the mesothermophilous forest survived in this region in the core of the Mediterranean basin during the Last Glacial Period (LGP, since ~36 ka cal BP), indicating that this area played an important role as a reservoir of woodland biodiversity. Here, Quercus pubescens was the most abundant component, followed by a wide variety of deciduous trees and Pinus nigra. Charcoal data also pointed at the crucial role of this coastal area, acting as a reservoir for warm temperate trees of genera Tilia, Carpinus and Sambucus, in LGP, in the Mediterranean region. Our modelling results showed that P. nigra might be the main candidate as a “Pinus sylvestris type” in the study site in the Last Glacial Maximum (LGM). Furthermore, we found that P. nigra might coexist with Q. pubescens in several European territories both currently and in the LGM. All models showed high levels of predictive performances. Our results highlight the advantage of combining different approaches such as charcoal analysis and ecological niche models to explore biogeographic questions about past and current forest distribution, with important implications to inform today’s forest management and conservation.

Potential distribution of two invasive pineapple pests under climate change

BACKGROUND

The number of global invasive species has significantly increased during the past two centuries due to globalization. The understanding of species invasion under climate change is crucial for sustainable biodiversity conservation, community dynamics, ecosystem function, and resource distribution. Two invasive species, Dysmicoccus brevipes (Cockerell) and D. neobrevipes (Beardsley) have greatly expanded their ranges during recent years. These insects are now considered as extremely serious pests for various plants, especially pineapple. In addition, they are the primary vectors for pineapple wilt associated virus. However, the potential distribution range and management strategies for these pests are unclear.

RESULTS

In this study, potential risk maps were developed for these pests with MaxEnt (maximum entropy) based on occurrence data under different environmental variables. The potential distributions of these pests were projected for 2050s and 2070s under three climate change scenarios as described in the Special Report on Emissions Scenarios of the Intergovernmental Panel on Climate Change. Results showed that both pests have similar potential distributions, with high environmental suitability in South America, Africa and South Asia. In addition, potential range expansions or reductions were predicted under different climate change scenarios. The annual mean temperature was the most important factor, accounting for 43.4% of D. brevipes distribution. The minimum temperature of coldest month and mean temperature of coldest quarter was found to be responsible for 90.3% of D. neobrevipes distribution.

CONCLUSION

This research provided a theoretical reference framework to develop policies in the management and control of these invasive pests. © 2019 Society of Chemical Industry.

Responses of an endangered brown bear population to climate change based on predictable food resource and shelter alterations

The survival of an increasing number of species is threatened by climate change: 20%-30% of plants and animals seem to be at risk of range shift or extinction if global warming reaches levels projected to occur by the end of this century. Plant range shifts may determine whether animal species that rely on plant availability for food and shelter will be affected by new patterns of plant occupancy and availability. Brown bears in temperate forested habitats mostly forage on plants and it may be expected that climate change will affect the viability of the endangered populations of southern Europe. Here, we assess the potential impact of climate change on seven plants that represent the main food resources and shelter for the endangered population of brown bears in the Cantabrian Mountains (Spain). Our simulations suggest that the geographic range of these plants might be altered under future climate warming, with most bear resources reducing their range. As a consequence, this brown bear population is expected to decline drastically in the next 50 years. Range shifts of brown bear are also expected to displace individuals from mountainous areas towards more humanized ones, where we can expect an increase in conflicts and bear mortality rates. Additional negative effects might include: (a) a tendency to a more carnivorous diet, which would increase conflicts with cattle farmers; (b) limited fat storage before hibernation due to the reduction of oak forests; (c) increased intraspecific competition with other acorn consumers, that is, wild ungulates and free-ranging livestock; and (d) larger displacements between seasons to find main trophic resources. The magnitude of the changes projected by our models emphasizes that conservation practices focused only on bears may not be appropriate and thus we need more dynamic conservation planning aimed at reducing the impact of climate change in forested landscapes.