Suitable Habitat Research Articles

A Machine Learning Algorithm‐Based Approach (MaxEnt) for Predicting Habitat Suitability of Formica rufa

ABSTRACTMachine learning techniques are quite effective for simulating species habitat appropriateness. Species distribution models are statistical algorithms founded on the ecological niche idea. These models estimate the association between existing species records and the environmental and spatial characteristics of the habitat. From 2022 to 2023, a field survey was conducted in the Kastamonu Forest Enterprise, resulting in the identification of 267 active Formica rufa nests. The habitat preferences of F.rufa were assessed based on factors such as stand characteristics, topography and climatic variables. MaxEnt, a prevalent machine learning technique for predicting species habitat suitability, was employed in the habitat suitability modelling of F. rufa. 30 distinct variables were employed in the modelling process. Receiver Operating Characteristic (ROC) analysis examined model accuracy. AUC was 0.941 for training data and 0.946 for test data. With 39.5% of the model, the development stage is the most important variable for F. rufa habitat selection. The development stage, productivity and temperature annual range (BIO7) variables make up 75.1% of the model. The habitat suitability map shows that 79% of F. rufa nests are in moderately and highly appropriate areas. The F. rufa group, widely prevalent in northern hemisphere forests, significantly impacts forest ecosystems and is recognised as the foremost bioindicator species within these environments. Determining the elements that affect habitat selection by these species is essential for their conservation and management.

Loss of habitat suitability and distribution range of the endangered Japanese giant salamander under climate change

Giant salamanders are the world’s largest amphibians and keystone predators in riverine ecosystems where they face global declines. Identifying environmental variables influencing their distribution is, therefore, an essential step for their conservation. This study aims to assess the current habitat suitability and distribution of the Japanese giant salamander (Andrias japonicus) and to predict changes under future climate scenarios. We used species distribution models (SDMs) over a 282,916 km² area, including 477 high-resolution occurrence data of giant salamanders and seven remote-sensing environmental predictors (climatic, topographic and land use). We projected the prediction maps, identified the most contributing variables and calculated the shifts of suitable areas for three periods (2050, 2070 and 2090) under projected climatic conditions. Climatic variables highly contributed to the distribution of giant salamanders (76% of the total), with preferences for areas with moderate precipitations during cold and wet seasons and mild summer temperatures. A moderately steep surrounding environment was favourable for salamanders, whereas the land-use variables had less influence. Future climate predictions indicate a major decrease of suitable areas. Altogether, our results highlight the habitat preferences of giant salamanders at a broad scale and the negative impact of climate change on future suitable areas. These findings provide important steps for upcoming conservation actions for this threatened species in delineating favourable distribution ranges and priority areas that should be directly affected by climate change. Finally, they emphasise the need for new research at a fine scale on disturbances to the aquatic habitat to enhance the conservation of giant salamanders. We used a species distribution model (MaxEnt), high-resolution occurrence data and remote sensing data (climatic, topographic and land use) to identify suitable habitats for the Japanese giant salamander in Japan. The most suitable environments for the Japanese giant salamander are located both within and beyond its current distribution range, with the ‘Japanese Alps’ forming an impassable natural barrier. Among the variables studied, precipitation of the warmest quarter, precipitation of the coldest quarter, mean temperature of the warmest quarter and mean temperature of the wettest quarter were the most important environmental predictors of the species’ distribution. Climate change is expected to severely reduce the potential suitable geographical areas for the Japanese giant salamander in the future. The present work calls for new surveys based on the projected maps to improve the mapping of salamander distribution and to focus on ecological features and threats at the aquatic habitat level to understand the risks to their populations.

Spatial Distribution of Illex argentinus in Different Life Stages of Mesoscale Eddies in Patagonian Waters

Mesoscale eddies are known to influence the abundance and distribution of oceanic cephalopods. However, little is known about these effects in the southwest Atlantic Ocean. Therefore, this study analyzed the variations in environmental conditions and the resource abundance, spatial distribution, and habitat suitability of Illex argentinus within different life stages of cyclonic (CE) and anticyclonic (AE) eddies in Patagonian waters. From a comparison of squid abundance between CEs and AEs at each life stage, it was found that I. argentinus gradually increased in abundance after eddy formation, that abundance peaked during eddy maturation and that it subsequently decreased during the eddies’ decay phase. Spatially, squid resources in AEs were primarily concentrated in the northwest and southeast peripheral regions of the eddy, while in CEs, resources were more concentrated in the outer regions, on the western side of the eddy. Environmental factor analysis revealed that sea surface temperature (SST) and temperature at 200 m depth (T200m) in both CEs and AEs reached their lowest values during the intensification and maturation phases of the eddies. Chlorophyll a (Chl-a) concentrations were significantly higher in CEs than in AEs from the formation to the maturation phase; however, during eddy decay, Chl-a concentrations were higher in AEs. According to a comparison of the suitability index (SI) for each environmental factor and the habitat suitability index (HSI) model, SISST, SIT200m, and SIChl-a in AEs increased and then decreased with eddy evolution, with optimal SI values occurring during the intensification phase. In CEs, SISST and SIT200m also increased and then decreased, with optimal SISST and SIT200m occurring during the intensification and maturation phases, respectively, with little variation in SIChl-a across the life cycle of CEs. The HSI in both types of eddies gradually increased from the formation phase, reached a peak during maturation, and significantly decreased during eddy decay. Overall, this study indicated that habitat suitability and resource abundance for I. argentinus were highest during the maturation phase of the eddies.

Predicting the habitat suitability of Ilex verticillata (Aquifoliaceae) in China with field-test validations.

The cut branches of Ilex verticillata are highly ornamental and have high economic value. Since its introduction to China, it has received widespread attention. In the context of climate change today, ensuring its promotion and sustainable production in China is of great significance. In this study we evaluated the habitat suitability of the species using MaxEnt, combined with climate and soil variables, to assess the impact of climate change on its potential suitable habitat. We used 121 I. verticillata occurrence data and validated the model prediction using extensive field testing (12 test sites located in areas from 23.19° N to 42.91° N and 76.17° E to 125.14° E). The habitat suitability model (AUC = 0.854) performed well. Among them, three precipitation variables and one temperature variable were the main factors determining the distribution of I. verticillata in China. Field trial tests and model predictions of the suitability of I. verticillata were consistent, indicating that our model predictions are biologically meaningful and economically valuable. Under the Shared Socioeconomic Pathways (SSPs) climate change scenario, the high and medium suitable habitats for this species will be reduced in the future climate. This study helps to better understand the impact of climate change on I. verticillata and provides suggestions for the introduction and cultivation areas and protection of this species in China.

Risk Prediction of Emerging Sites Infested with Schistosome-Transmitting Oncomelania hupensis in Shanghai, China.

Oncomelania hupensis, the sole intermediate host of Schistosoma japonicum, plays an essential role in the transmission of schistosomiasis. In 1985, snails were eliminated throughout Shanghai city. However, snail-infested sites have continuously emerged since the 1990s. The resurgence of snail habitats may signal the recurrence of schistosomiasis. Therefore, implementing continuous monitoring measures for snails is crucial, and predicting potential habitats for snails in Shanghai is essential for enhancing surveillance effectiveness, providing early warnings to health authorities, optimizing resource allocation, maintaining the elimination status of schistosomiasis in Shanghai, and ultimately, advancing the goal of eliminating schistosomiasis in China. Our research developed an ensemble model to predict the current and future distributions of snails in Shanghai by collecting emerging snail-infested records from 1991 to 2020 and integrating them with 19 environmental variables, including climate, geography, and socioeconomics. The ensemble model identified the annual average surface temperature as the most significant factor influencing snail occurrence. The highly suitable areas were primarily located in the northwestern part of Jinshan District and the southern part of Songjiang District. In the future, the southwestern part of Shanghai will continue to provide suitable habitats for snails in the long term. Therefore, even in areas where schistosomiasis has been eliminated, surveillance of snails and the disease should not be relaxed, and ongoing monitoring in these areas is necessary.

A possum’s cautionary tale: targeted surveys in north-eastern Victoria fail to detect Leadbeater’s possum in remnant forest within its historic range

Endemic to Victoria, the range-restricted, Critically Endangered Leadbeater’s possum (Gymnobelideus leadbeateri) historically had a much broader distribution from south-east of Melbourne, through the wet forests of eastern Victoria, and extending into New South Wales. Undetected populations of this cryptic species may persist within forested sections of this historic range, despite these landscapes having been subject to significant disturbance through clearing, logging, and bushfires. The adoption of arboreal camera trapping has permitted targeted surveys for Leadbeater’s possum to be conducted with greater efficiency and reliability. Between 2017 and 2019, we conducted arboreal camera-trapping surveys for Leadbeater’s possum in seven patches of potentially suitable habitat, that were 13–145 km outside the species’ known range in Victoria’s Central Highlands. Site selection was informed by habitat suitability modelling. The species was detected at only one of seven areas surveyed, the patch closest to the possum’s current known range (~13 km). Notable occurrences of other cryptic arboreal mammals were recorded in rarely surveyed habitat types and at high elevations (>1000 m). Despite north-eastern Victoria’s significant remnant forest cover, the apparent loss of Leadbeater’s possum from its historic range in this region provides a cautionary tale regarding declining forest condition owing to major disturbance from fire and logging.

Potential Habitats of Siamese Crocodiles and False Gharials in East Kalimantan for Conflict Resolution

Concerns in crocodiles sustainability have long been overlooked, due to humans fear of its ferocity and unresolved human-crocodile conflicts. The siamese crocodile (Crocodylus siamensis) and false gharial (Tomistoma schlegelii) are considered threatened by the IUCN red list because of their limited range and declining populations. In this study we developed habitat suitability model for both species and overlaid with anthropogenic factors to mitigate conflict between crocodiles and human in Mesangat-Suwi Wetland, East Kalimantan, Indonesia. We collected species presence from 2018–2023, measured environmental variables, interviewed 100 respondents, and mapped all information with Maximum Enthropy program (MaxEnt). Results showed that different factors influenced the habitat distribution for each species. Specifically, distance from swamps was affected the most for both crocodiles. Our model found that the potential habitat was much smaller than the non-potential ones due to humans’ intrusion. Much of the Mesangat-Suwi area was covered in high-conflict zones between humans and crocodiles, endangering both species even more. Hence, serious actions were urgently needed to resolve the conflict, either by prevention and mitigation actions, to ensure human-crocodile coexistence in East Kalimantan.

Evaluating the Centre‐Periphery Hypothesis Through Genomic Phylogeographical Comparisons of Two Sister Species of Liquidambar in East Asia's Tertiary Relict Forests

ABSTRACTAimUnderstanding the spatial distribution of genetic variation within species is a central tenet in evolutionary biology and conservation biology. This study explores how historical demographic processes and/or environmental factors interact to affect contemporary genetic variation and adaptive potential, with a specific focus on testing the ‘centre‐periphery’ hypothesis (CPH).LocationSubtropical China.Taxon Liquidambar. MethodsWe combined comparative phylogeography, landscape genomics and niche modelling to investigate the interplay between demographic history and past/current environmental factors in shaping genetic variation in Liquidambar formosana and L. acalycina, a sister pair of East Asia's Tertiary relict forests.ResultsIn both species, core populations occupied highly suitable habitats at highest densities. Consistent with the CPH, population genetic diversity decreased, and differentiation increased, from centre to margin in L. acalycina, but not in L. formosana, likely reflecting different demographic histories and different relative contributions of geography, past (LGM) and current climates to their present‐day genetic variation. In addition, L. formosana showed higher adaptive potential to future climate change than L. acalycina.Main ConclusionsThis study demonstrates that differences in contemporary genetic variation and adaptability among closely related species can be explained by contrasting demographic responses to multiple geographic/climatic factors. In turn, it should also expand our understanding of the CPH, while informing future conservation efforts for these two study species.

Global range extension of bioclimatic zone of Bruguiera hainesii C.G.Rogers 1919 (Rhizophoraceae)

Bruguiera hainesii is a rare mangrove species with limited populations worldwide, but there is lack of detailed knowledge about its population size and distribution in Vietnam. Its regeneration capacity is notably low, raising concerns about its long-term survival. This study aims to model the bioclimatic niche of B. hainesii to identify potential ecological regions in Vietnam suitable for its conservation and survival under current and future climate scenarios. Occurrence data were collected from the global GBIF database and recent field surveys in Vietnam conducted during 2023–2024. The Maxent model was used to predict bioclimatic suitability, with projections extended to future climate scenarios using ACCESS-CM2 under SSP2-4.5 (medium-emission scenario) for 2080–2100. The study identified Vietnam as a highly suitable region for B. hainesii despite its small population size. Projections indicate a potential expansion of ideal habitats under future climate conditions, highlighting the species' adaptability. The findings provide valuable insights into the conservation of B. hainesii, emphasising the importance of preserving existing populations and managing suitable habitats to ensure the species' long-term survival and regeneration. This research also underscores the role of bioclimatic niche modelling in guiding conservation strategies for endangered mangroves.

Identifying corridors for Asiatic black bear (Ursus thibetanus) in a part of Eastern Himalayas, India

The Asiatic black bear (Ursus thibetanus), classified as a vulnerable species on the IUCN Red List, is an important mammal species found in the state of Sikkim, India. Studies carried out in Khangchendzonga National Park have documented the presence of these bears, highlighting their crucial conservation importance in the region. The population of Black bears are restricted to small habitat patches, which over the years have become fragmented by road networks and urban settlements. In such fragmented landscapes, connecting corridors play a crucial role in maintaining wildlife movement and genetic diversity. We assessed connectivity between eight protected areas in Sikkim using MaxENT and Circuitscape. 65 black bear presence locations (collected through Camera traps and sign surveys) and 24 environmental variables were used to model the corridors. Habitat suitability map was generated through MaxENT modelling approach. Our analysis suggests that there are multiple options to maintain connectivity for black bears in Sikkim. We mapped seven corridors and five pinch points (bottlenecks in connectivity), and calculated metrics to estimate their quality and importance. Our model output was supported by high AUC value (0.921) and field validation by questionnaire surveys and sign surveys to assess black bear presence and habitat use. Our results showed that 300 km² of the suitable regions are within the protected areas in Sikkim. The highest quality linkages as measured by the ratio of cost-weighted distance to Euclidean distance (CWD:EucD) and cost-weighted distance to least-cost path (CWD:LCP) were Khangchendzonga and Barsey, suggesting that these protected areas (National Parks and Wildlife Sanctuaries) and the developed corridors play important role in maintaining connectivity. We mapped pinch-points which are habitat where black bear movement is restricted due to unfavorable environments, linear infrastructures, built up/settlements or a combination of factors and our model predicted pinch points near few settlement areas; Mangan, Dikchu, Pangthang, Kabi, Yuksum and Lachen. Ground truthing confirmed that these areas also coincide with Black bear conflict zones in Sikkim.

Common dolphin's shipping noise risk assessment on the Portuguese coast.

Ocean noise generated by human activities at sea has been increasing over the decades, affecting marine ecosystems. Ship traffic flow between the Mediterranean or South Atlantic and northern Europe makes the coast of Portugal one of the most intense shipping highways on a global scale. Among the cetaceans of the coast of Portugal, the common dolphin (Delphinus delphis) was selected as a target species. Based on 15years of observations, the common dolphins' habitat suitability was estimated, together with the shipping noise maps for the year 2019, to produce seasonal risk maps for the same year. A large number of areas with a high noise risk index (≥0.85) were found in Portugal's southern and southwestern coasts, especially during the summer and fall seasons. Comparably, the 0.50 risk index exceeds 7% and 3.5% of the total area in summer and fall, respectively. These percentages decrease to 1% in spring and winter.

Shifts in habitat suitability for harbour porpoises leads to reduced importance of marine protected areas

Shifts in habitat suitability for harbour porpoises leads to reduced importance of marine protected areas

Climate change causes reductions in fish habitat suitability in Loktak Lake, India

Climate change causes reductions in fish habitat suitability in Loktak Lake, India

Shelter Distribution and Type Affect Space Use of a Desert Reptile.

Animal home ranges derive from the distribution of resources across the landscape. For example, home ranges of most tortoise species in the United States revolve around networks of burrows. However, human disturbances that damage shelters can decrease habitat suitability, individual survival, and population persistence. We investigated effects of burrow distribution and availability on space use of the Sonoran Desert Tortoise Gopherus morafkai at two populations with different habitat structures to determine the extent to which habitat capacity is defined by factors subject to management, such as vegetation, relative to more permanent features such as rock shelters. We also demonstrated the superiority of autocorrelated kernel density estimation, illustrating flawed conclusions that could arise from the use of traditional home-range estimators. Home-range size increased with the number of available burrows at both sites. At the Florence Military Reservation (FMR), with numerous caliche caves and few rock burrows, larger home ranges effectively compensated for one third the burrow density as that of Sugarloaf Mountain, which predominantly featured rock burrows. Female tortoises had smaller home ranges than males despite having similar burrow densities. Females revisited individual burrows more often than males at Sugarloaf, which may relate to female use of preferred nesting sites; however, lower availability led males to revisit burrows at similar rates as females at FMR. Pairs of tortoises at FMR shared 72% more burrows than pairs at Sugarloaf, and pairs of females shared 33% fewer burrows than female-male pairs across both sites. Space and burrow use at FMR and Sugarloaf are consistent with predictions of how animals choose patches for their home ranges in ways that are optimal with respect to spatially distributed resources. Populations largely reliant on pallets or soil burrows may be more subject to declines due to anthropogenic impacts from grazing or off-highway vehicle use or due to increasing temperatures.

Bayesian networks facilitate updating of species distribution and habitat suitability models

Bayesian networks facilitate updating of species distribution and habitat suitability models

Advancing Management of the Main Predatory Sharks Along the Argentine Coast: Leveraging Habitat Use Knowledge and Historical Catch Data

ABSTRACTThis study investigates the spatial overlap in habitat use among four key predatory species—school shark (Galeorhinus galeus), broadnose sevengill shark (Notorynchus cepedianus), copper shark (Carcharhinus brachyurus) and sand tiger shark (Carcharias taurus)—along the Argentine coast to identify important areas for joint management. Leveraging habitat suitability predictions for these predators, we generated annual and seasonal maps to identify significant regions of habitat overlap. Notably, the coastal zone between the Uruguayan and northern Argentine coasts emerged as crucial for developing fishery management and conservation strategies for these four species. Historical catch data also identified important zones for recreational fishing and potential nursery sites, stressing the need for targeted management of the coastal area between Punta Rasa and Mar del Plata (36.3°–38° S). This highlights the necessity of comprehensive fishing regulations with stronger enforcement in the unregulated provincial waters of Chubut and Santa Cruz, as well as the Uruguayan coast. Our findings underscore the importance of integrating species‐specific ecological data in designing marine protected areas and conservation strategies tailored to the unique life history and movement patterns of these sharks. Additionally, the study emphasizes the need for adaptive, multijurisdictional management strategies to accommodate the migratory nature of these species across provincial and national waters. The implications of these findings are discussed within the context of current chondrichthyan policy in Argentina, presenting a foundational basis for informing future management strategies aimed at sustaining shark populations in the Southwest Atlantic.

Analysis of the Distribution Pattern of Asparagus in China Under Climate Change Based on a Parameter-Optimized MaxEnt Model

Asparagus (Asparagus officinalis L.) has high health and nutritional values, but the lack of scientific and rational cultivation planning has resulted in a decline in asparagus quality and yield. Important soil, climatic, anthropogenic, and topographic environmental factors influencing the distribution of asparagus cultivation were chosen for this study. The Kuenm package in the R language (v4.2.1) was employed to optimize the maximum entropy model (MaxEnt). Pearson’s correlation analysis, optimized MaxEnt, and geographic information spatial technology were then utilized to identify the main environmental factors that influence suitable habitats for asparagus in China. Potential distribution patterns, migration, and changes in trends concerning the suitability of asparagus in China under various historical and future climate scenarios were modeled and projected. Human activities and climate factors were found to be the primary environmental factors that influence the suitability distribution of asparagus cultivation in China, followed by soil and topographic factors. Historical suitable habitats covered 345.6 × 105 km2, accounting for 36% of China. These habitats are projected to expand considerably under future climatic conditions. This research offers a basis for the rational planning and sustainable development of asparagus cultivation.

Re-emergence of Aedes aegypti (Linnaeus) in Egypt: Predicting distribution shifts under climate changes.

Aedes aegypti, the primary vector of several medically significant arboviruses-including dengue fever, yellow fever, chikungunya and Zika-was successfully eradicated from Egypt in 1963. However, since 2011, there have been increasing reports of its re-emergence, alongside dengue outbreaks in southern Egyptian governorates, raising significant public health concerns. This study aimed to model the current and future distribution of Ae. aegypti in Egypt. Local occurrence data were integrated with bioclimatic, anthropogenic and biological environmental variables to identify key factors influencing the distribution of Ae. aegypti. Maximum entropy (MaxEnt) modelling demonstrated strong predictive performance (area under the receiver operating characteristic curve [AUC] mean = 0.975; true skill statistic [TSS] mean = 0.789). The key determinants of habitat suitability were identified as human population density, annual precipitation and the normalised difference vegetation index (NDVI). Current predictions indicate that suitable habitats for Ae. aegypti are concentrated in the Nile Valley, Nile Delta, Fayoum Basin, Red Sea coast and South Sinai. Projections under future climate change scenarios suggest an expansion of suitable habitats, particularly in the Nile Delta region. By 2050, the model predicts a 61%-68% increase in suitable habitat area, with a further 64%-69% increase by 2070, depending on the future climate scenarios. These findings are crucial for informing vector control and disease prevention strategies, particularly considering Egypt's status as one of the world's leading tourist destinations.

Effects of Climate Change on the Distribution of Papilio xuthus

The Papilio xuthus is a widely distributed species in the genus Papilio of the family Papilionidae, possessing ecological, ornamental, and socio-economic service values. To determine the ecological role of P. xuthus and assess its population distribution under future climate change scenarios, this study utilized the MaxEnt model to predict the geographic distribution of P. xuthus in the future and evaluate its population dynamics. The results indicated that P. xuthus is currently widely distributed in East Asia, with a high suitability area of 1827.83 × 103 km2, primarily in China, Japan, North Korea, and South Korea. Climate change has a significant impact on the geographic distribution of P. xuthus, with its high suitability areas decreasing in the future, particularly within China, where the change is projected to be as high as 46.46% under the SSP126 scenario by the 2050s. The centroid of its high-suitability area is expected to shift northeastward. Key environmental variable analysis revealed that Temperature Seasonality, Mean Temperature of the Wettest Quarter, Precipitation of the Wettest Month, and Precipitation of the Warmest Quarter are critical factors influencing the selection of suitable habitats by P. xuthus. This study assessed the distribution of P. xuthus and provided conservation recommendations, offering a reference for future population control and conservation efforts.

Adapting to change: exploring the distribution dynamics of the alien and potentially invasive aphid species Cinara curvipes (Hemiptera: Aphididae) in the context of global warming

This study investigates the potential ecological niche and distribution of the Nearctic bow-legged fir aphid, Cinara curvipes, an alien and potentially invasive species, across Europe. Utilising climate modelling based on climatic preferences in its native range, we assess the suitability of European climates for facilitating the spread of this aphid. Coupled with the presence of suitable host plants, mostly firs (Abies spp.) or cedars (Cedrus spp.), there is potential for the bow-legged fir aphid to extend its range across most European regions, with projections suggesting potential expansion into Asia Minor. Furthermore, future climate scenarios predict a northward expansion of suitable habitats for this aphid species, confirmed by its detection in Denmark and Norway. Our research reveals that C. curvipes displays notably higher fecundity compared to its Cinara genus counterparts. Specifically, wingless viviparous females of this species achieve peak fecundity at lower temperatures (10–15°C), explaining their spring mass appearances. At 25°C, nymphs fail to moult or reach maturity, leading to summer population declines. Unique survival mechanisms, including the production of numerous winged morphs under overcrowded conditions, enable rapid dispersal facilitated by human-mediated transport, notably through the “Christmas trees” trade. Its high reproductive output allows the species to quickly colonise new habitats and exploit available resources, contributing to its potential invasiveness. We emphasise the critical need for collaborative engagement among researchers, stakeholders, and the public to bolster citizen science initiatives and reinforce environmental monitoring networks, all within the framework of an early detection and rapid response (EDRR) process. This collaborative approach is vital for effective environmental management and mitigating potential invasive threats.