High Habitat Suitability Research Articles

Spatiotemporal risk assessment for avian influenza outbreak based on the dynamics of habitat suitability for wild birds.

Highly pathogenic avian influenza (HPAI) has predominantly damaged the poultry industry worldwide. The fundamental prevention and control strategy for HPAI includes early detection and timely intervention enforcement through a systematic surveillance system for wild birds based on the ecological understanding of the dynamics of wild birds' movements. Our study aimed to develop a spatiotemporal risk assessment model for avian influenza (AI) infection in wild birds to empower surveillance information for a contingency strategy. For this purpose, first, we predicted the monthly habitat suitability of seven waterfowl species, using 227,671 Global Positioning System (GPS) tracking records of 562 birds from 2014 to 2018 in the Republic of Korea (ROK). Then, that predicted habitat suitability and 421 coordinates of AI detection sites in wild birds were used to build the risk assessment model. Subsequently, we compared the monthly predicted risk of avian influenza virus (AIv) identification in wild birds between case and non-case poultry farms with HPAI H5N6 outbreak in the ROK between 2016 and 2017. The results reported considerable variation of monthly habitat suitability of seven waterfowls and the impact of predicting AI occurrences in wild birds. The high habitat suitability for spot-billed ducks (contribution rate in November=40.9%) and mallards (contribution rate in January=34.3%) significantly contributed to predicting the average risk of AIv identification in wild birds, with high predictive performance [the monthly mean of area under the curve (AUC)=0.978]. Moreover, our model showed that the averaged risk of identification AI in wild birds was significantly higher in HPAI infected premises, with infected domestic duck holdings exhibiting a significantly higher risk than the chicken farms in November. This study suggests that animal health authority establishes a risk-based HPAI surveillance system grounded on the ecological nature of wild birds to improve the effectiveness of prevention and preparedness of emerging epidemics.

Impact of Land Use Changes on Habitat Quality in Altay Region

Altay region is located in the northern part of Xinjiang, and has complex and diverse internal geomorphic types, undulating terrain and a fragile ecosystem. Studying the impact of land use changes on habitat quality is of great significance to regional ecological protection and development, rational planning and utilization, and ensuring the sustainable development of the ecological environment. Based on the InVEST model, combined with land use panel data and topographic relief data of the Altay region, this paper studied the habitat quality from 1995 to 2018. The results show that cultivated land, water area and construction land increased gradually from 1995 to 2018, while grassland and unused land decreased. Forestland remained stable in the first five periods, but increased significantly in 2018. During 1995–2018, all land use types were transferred, mainly between cultivated land, forestland, grassland and unused land in the flat and slightly undulating areas. Poor habitat quality was dominant during 1995-2018. Habitat quality decreased significantly in 2015, which was related to the rapid expansion of cultivated and construction land as threat sources, as well as the decrease of forest and grassland as sensitive factors. However, habitat quality improved significantly in 2018, because a large amount of cultivated land and unused land were converted into forest land and grassland with high habitat suitability. Land use type has an important influence on habitat quality. The distribution characteristics of habitat quality for topographic relief types from good to bad were: large undulating area>medium undulating area>small undulating area>flat area>slightly undulating area. The findings of this study are of great significance for coordinating social, economic, and ecological development in this region and in similar areas.

Modeling Mackerel Tuna (Euthynnus affinis) Habitat in Southern Coast of Java: Influence of Seasonal Upwelling and Negative IOD

We used fishery catch data from Cilacap Fishing Port and Copernicus data set in July 2016-December 2017 to investigate the impacts of Indian Ocean Dipole (IOD) on upwelling and mackerel tuna distribution in the southern coast of Java. This study implemented a Generalized Additive Model (GAM) for habitat prediction of mackerel tuna in the waters. The present study showed that the extreme negative IOD in 2016 caused a weaker southeasterly wind and even a reversal to the northwesterly wind, as seen off Sumatra in September 2016. The situation produced vertically mixed layer thickening and no upwelling during the southeast monsoon event 2016, consequently resulted in warmer temperature and fewer Chlorophyll-a (Chl-a) compared to the southeast monsoon event 2017. The mackerel tuna production significantly dropped in 2016 and rose in 2017, particularly during the upwelling event. The high Habitat Suitability Index (HSI) was found in southern Central Java in July 2017, expanded bigger in August 2017, and decreased in September 2017. During July and August 2016, the high HSI covered only a less area in the region and disappeared in September 2017. The high HSI indicates that the oceanographic factor is consistent with the catch probability of mackerel tuna.

The Invasion of Megachile policaris (Hymenoptera: Megachilidae) to Hawai'i.

Islands are insular environments that are negatively impacted by invasive species. In Hawai'i, at least 21 non-native bees have been documented to date, joining the diversity of >9,000 non-native and invasive species to the archipelago. The goal of this study is to describe the persistence, genetic diversity, and natural history of the most recently established bee to Hawai'i, Megachile policaris Say, 1831 (Hymenoptera: Megachilidae). Contemporary surveys identify that M. policaris is present on at least O'ahu, Maui, and Hawai'i Island, with the earliest detection of the species in 2017. Furthermore, repeated surveys and observations by community members support the hypothesis that M. policaris has been established on Hawai'i Island from 2017 to 2020. DNA sequenced fragments of the cytochrome oxidase I locus identify two distinct haplotypes on Hawai'i Island, suggesting that at least two founders have colonized the island. In their native range, M. policaris is documented to forage on at least 21 different plant families, which are represented in Hawai'i. Finally, ensemble species distribution models (SDMs) constructed with four bioclimatic variables and occurrence data from the native range of M. policaris predicts high habitat suitability on the leeward side of islands throughout the archipelago and at high elevation habitats. While many of the observations presented in our study fall within the predicted habitat suitability on Hawai'i, we also detected the M. policaris on the windward side of Hawai'i Island suggesting that the SDMs we constructed likely do not capture the bioclimatic niche flexibility of the species.

Predicting potential suitable habitats of Chinese fir under current and future climatic scenarios based on Maxent model

The continuous global climate change has affected the living habits, morphological characteristics and spatial distribution of tree species. Chinese fir (C. lanceolata (Lamb.) Hook) is one of the most important conifer tree species in China, which plays a major role in terms of timber supplies and environment protection. Predict the potential suitable habitats of Chinese fir under different climatic scenarios, can not only provide scientific theoretical basis for the planning and planting of Chinese fir, but also have great significance for maintaining the stability of the plantation ecosystem. Here, we used the maximum entropy (Maxent) model which optimized by the ENMeval package, to predicted the potential suitable habitats for Chinese fir under current climatic conditions and two climatic scenarios in 2070s. Our results showed that the complexity of the model was relative low, when the regularization multiplier (RM) was 0.5 and feature combination (FC) was linear (L) and quadratic (Q). Under this parameter setting, the high and moderate suitable habitat area of Chinese fir were 83.90 × 104 km2 and 97.62 × 104 km2, respectively, which suggested we can carry out Chinese fir planting activities with different cultivation purposes. The minimum temperature of the coldest month, annual precipitation, annual mean temperature and mean temperature of warmest quarter were identified as the essential factors shaping habitat suitability for Chinese fir. Under future climate scenarios, the high suitable habitat was reduced and the degree of fragmentation was increased, and the total potential suitable habitat of Chinese fir had the tendency to migrate to high-altitude regions. Managers should be cautious about the cultivation area selection of Chinese fir plantation as the potential suitable habitat changed under the global climate change continuously. It is therefore imperative to adjust the long-term management and protection strategy of Chinese fir plantation.

Habitat Quality Effect and Driving Mechanism of Land Use Transitions: A Case Study of Henan Water Source Area of the Middle Route of the South-to-North Water Transfer Project

Accelerating urbanization and industrialization have had substantial impacts on economic and social activities, changed the surface environment of the earth, and affected global climate change and biodiversity. If reasonable and effective management measures are not implemented in time, unchecked urbanization and industrialization will damage the structure and function of the ecosystem, endanger human and biological habitats, and ultimately lead to difficulties in achieving sustainable development. This study investigates the habitat quality effect of land use transition and analyzes the cause and mechanism of such changes from an economic–social–ecological complex system perspective in the Henan Water Source (HWS) area of the Middle Route of the South-to-North Water Transfer Project (MRP). The study comprehensively examines the characteristics of land use transition from 2000 to 2020. The results indicate that the habitat quality of the HWS area of the MRP decreased slowly over the past 20 years, with a more obvious decrease in the past 10 years. Specifically, the proportion of high quality habitat areas is relatively large and stable, and the medium and low quality habitat areas increase significantly. Analyzing the change degree of the proportion of different levels of habitat quality area in each county, revealed that Dengzhou City had the most dramatic change, followed by the Xichuan and Neixiang counties; other counties did not undergo obvious change. The results of habitat quality factor detection by GeoDetector showed that land use transition plays a decisive role in the change of habitat quality. The types of land use with high habitat suitability compared to those with low habitat suitability will inevitably lead to a decrease in habitat quality. Additionally, elevation, slope, landform type, and annual precipitation are important factors affecting the habitat quality in the HWS area of the MRP, indicating that ecological factors determine the background conditions of habitat quality. The gross domestic product (GDP) per capita, the proportion of agricultural output value, grain yield per unit area in economic factors, population density, and urbanization rate in social factors affect the spatial differentiation of habitat quality to a certain extent. Soil type, annual mean temperature, vegetation type, and NDVI index have weak effects on habitat quality, while road network density and slope aspect have no significant effect on habitat quality. The results of this study provide a basis for the improvement of habitat quality, ecosystem protection and restoration, land resource management, and related policies in the HWS area of the MRP. They also provide references for the research and practice of the habitat quality effects of land use transition in other regions.

Assessing potential habitat distribution range of the endangered tree species Pterocarpus marsupium Roxb. Under the climate change scenario in India

Pterocarpus marsupium Roxb., a significant deciduous tree species of high medicinal value is depleting fast due to various biotic and abiotic factors and is included in the near threatened species category of IUCN red list. The potential distribution range of P. marsupium for India was modeled for the year 2020 and 2050 under different Representative Concentration Pathways (RCP 2.6, 4.5, 6.0 8.5) scenarios of climate change using Maxent, to study the impact of climate change on its distribution. The study revealed that at present ~3.08% geographical area of India is highly suitable to distribution of P. marsupium and depending upon RCP this may expand upto ~ 3.11-3.53% by 2050. The zone wise analysis for the present climatic conditions predicted prominent presence of high suitable habitat range of P. marsupium in the central zone comprising ~ 1.82% of the total geographical area of India followed by southern and western zones with ~ 0.53% and ~ 0.49% distribution area respectively. The study predicted northward shifting of suitable habitat by 2050 with an increase in suitable area in the range of ~0.6-11%, ~6.4-24.5% and ~20-60% for the central, southern and western zone respectively, but ~26%-53% decrease in the eastern zone. Annual precipitation (Bio_12) was the most significant contributor variable in limiting the distribution of P. marsupium for the present as well as future climatic conditions. The result provides baseline information for identification and prioritization of areas for the conservation and promotion of P. marsupium in India.

Origin and Potential Expansion of the Invasive Longan Lanternfly, Pyrops candelaria (Hemiptera: Fulgoridae) in Taiwan.

Simple SummaryThe longan lanternfly Pyrops candelaria (Linnaeus), which feeds on longan trees, has invaded the main island of Taiwan. Thus, this study aimed to (1) trace the origin of invasion, (2) predict habitat suitability and (3) study the risk of lanternfly spread into crop cultivation areas. We reconstructed the longan lanternfly phylogeny to compare haplotypes among different regions. In addition, we predicted the habitat suitability for the species based on MaxEnt and then matched it with longan and pomelo cultivation areas. Our results indicated that the Taiwanese populations of longan lanternfly might originate from the Kinmen Islands and the plain areas of Taiwan are considered to have high habitat suitability.The longan lanternfly Pyrops candelaria is a new invasive species on the main island of Taiwan. The introduction of an invasive species may negatively influence the native fauna, flora and environment. Thus, this study aimed to infer the invasion history, predict habitat suitability and potential expansion and assess the risk to crop cultivation areas in Taiwan. Genetic structures of P. candelaria from the main island of Taiwan and related regions were analyzed based on partial COI and ND2 sequences. Additionally, machine learning MaxEnt was utilized to study habitat suitability. The results suggested that the Taiwanese populations may originate from the Kinmen Islands and the plain areas of Taiwan are considered to have high habitat suitability. Furthermore, most of the cultivation areas of longan and pomelo crops showed high habitat suitability.

Human activity strongly influences genetic dynamics of the most widespread invasive plant in the sub-Antarctic.

The link between the successful establishment of alien species and propagule pressure is well-documented. Less known is how humans influence the post-introduction dynamics of invasive alien populations. The latter requires studying parallel invasions by the same species in habitats that are differently impacted by humans. We analysed microsatellite and genome size variation, and then compared the genetic diversity and structure of invasive Poa annua L. on two sub-Antarctic islands: human-occupied Marion Island and unoccupied Prince Edward Island. We also carried out niche modelling to map the potential distribution of the species on both islands. We found high levels of genetic diversity and evidence for extensive admixture between genetically distinct lineages of P. annua on Marion Island. By contrast, the Prince Edward Island populations showed low genetic diversity, no apparent admixture, and had smaller genomes. On both islands, high genetic diversity was apparent at human landing sites, and on Marion Island, also around human settlements, suggesting that these areas received multiple introductions and/or acted as initial introduction sites and secondary sources (bridgeheads) for invasive populations. More than 70years of continuous human activity associated with a meteorological station on Marion Island led to a distribution of this species around human settlements and along footpaths, which facilitates ongoing gene flow among geographically separated populations. By contrast, this was not the case for Prince Edward Island, where P. annua populations showed high genetic structure. The high levels of genetic variation and admixture in P. annua facilitated by human activity, coupled with high habitat suitability on both islands, suggest that P. annua is likely to increase its distribution and abundance in the future.

Long-term determinants of the seroprevalence of the bluetongue virus in deer species in southern Spain

Bluetongue is a vector-borne disease affecting domestic and wild ruminants, with a major socioeconomic impact. Endemic circulation of the bluetongue virus serotype 4 (BTV-4) and BTV-1 have occurred in Spain since 2004 and 2007, respectively. However, epidemiological studies have seldom been approached from a long-term perspective in wild ruminants. A total of 881 deer (red deer and fallow deer) were necropsied from 2005 to 2018 as part of the DNP health-monitoring program. Serum samples were tested for antibodies against BTV with the aims of assessing the temporal trend and to evaluate the modulating factors: individual, populational, environmental, and stochastic. Red deer displayed statistically significant higher seroprevalences of BTV (SBT; 78.6±3.8%) than fallow deer (53.1±4.7%). The detection of BTV-1 and BTV-4 by the serum neutralization test in calves suggested the circulation of both serotypes over the study period. For red deer, wet years together with high densities could provide suitable conditions for vector borne BTV transmission. Moreover, proximity to high suitability habitat for Culicoides, permanent pasturelands, was associated with higher SBT. The differences in the ecology and behaviour of deer species influencing the exposure to the vectors could determine the differences found in the SBT patterns. This study evidences the role that deer species may play in the maintenance of BTV, however, elucidating the epidemiological role of host in different contexts as well as the consequences of climate change on the competent vector populations and its potential effect on the dynamics of BTV infection in hosts communities deserve further research.

Forecast of climate change impact on habitat suitability of Linaria uralensis Kotov (Scrophulariaceae) in the Southern Urals

Rare plant species are the most vulnerable components of vegetation cover under climate change. The aim of this paper was to model the influence of climatic changes on the habitat suitability for Linaria uralensis Kotov in the Southern Urals. The MaxEnt program was used for modeling. Climate variables from CHELSA BIOCLIM and topographic variables of the digital elevation model were used as predictors. An ensemble of four future climate models under the RCP4.5 (moderate) and RCP8.5 (high) climate change scenarios was used to estimate potential changes in habitat suitability in the middle and second half of the 21st century. The modeling results showed that the species L. uralensis has a fairly high drought tolerance. The habitat conditions of this species will potentially be preserved in the area of its current distribution. Under moderate and high climate change some increase in the areas of high and medium habitat suitability is expected. Thus, it can be predicted that existing protection measures for this species will be sufficient, and there will be no need for additional conservation measures.

Distribution and Potential Limiting Factors of the European Pond Turtle (Emys orbicularis) in Eastern Europe

In order to use an integrated approach for studying the influence of risk factors on the distribution of the native turtle species E. orbicularis and accompanying invasive species (T. scripta and N. procyonoides) in the northeast of their range, we used GIS modelling and a database (GAEZ, human footprint, CliMond) of 55 preselected variables, which represent a system of bioclimatic and anthropogenic factors. The main variables that influenced the results were factors related to temperature. There was a high correlation (r = 0.6) between the species distribution model’s habitat suitability for E. orbicularis and the corresponding “human footprint” values within the European part of the species’ natural range. Its unpretentiousness towards anthropogenic factors would likely help the further expansion of its range in eastern Europe, because the areas with the highest habitat suitability (r > 0.7) were projected to increase 3.3-fold. When comparing the E. orbicularis model to those obtained for N. procyonoides and T. scripta, we concluded that N. procyonoides could be dangerous because it occupies similar habitats (the degree of correlation is reasonably high in the north of their range (r = 0.5) in Latvia). An expansion of the range of Trachemys scripta is also possible in the future within the northern territories. Therefore, when developing the turtles’ protection algorithms, it is also necessary to take into account the influence of invasive species.

Modeling Seasonal Distribution of Irrawaddy Dolphins (Orcaella brevirostris) in a Transnational Important Marine Mammal Area

Fishing activities continue to decimate populations of marine mammals, fish, and their habitats in the coastal waters of the Kep Archipelago, a cluster of tropical islands on the Cambodia-Vietnam border. In 2019, the area was recognized as an Important Marine Mammal Area, largely owing to the significant presence of Irrawaddy dolphins (Orcaella brevirostris). Understanding habitat preferences and distribution aids in the identification of areas to target for monitoring and conservation, which is particularly challenging in data-limited nations of Southeast Asia. Here, we test the hypothesis that accurate seasonal habitat models, relying on environmental data and species occurrences alone, can be used to describe the ecological processes governing abundance for the resident dolphin population of the Kep Archipelago, Cambodia. Leveraging two years of species and oceanographic data—depth, slope, distance to shore and rivers, sea surface temperature, and chlorophyll-a concentration—we built temporally stratified models to estimate distribution and infer seasonal habitat importance. Overall, Irrawaddy dolphins of Kep displayed habitat preferences similar to other populations, and were predominately encountered in three situations: (1) water depths ranging from 3.0 to 5.3 m, (2) surface water temperatures of 27–32°C, and (3) in close proximity to offshore islands (< 7.5 km). With respect to seasonality, statistical tests detected significant differences for all environment variables considered except seafloor slope. Four predictor sets, each with a unique combination of variables, were used to map seasonal variation in dolphin habitat suitability. Models with highest variable importance scores were water depth, pre- and during monsoon season (61–62%), and sea surface temperature, post-monsoon (71%), which suggests that greater freshwater flow during the wet season may alter primary productivity and dolphin prey abundance. Importantly, findings show the majority of areas with highest habitat suitability are not currently surveyed for dolphins and located outside Kep’s Marine Fisheries Management Area. This research confirms the need to expand monitoring to new areas where high-impact fisheries and other human activities operate. Baseline knowledge on dolphin distribution can guide regional conservation efforts by taking into account the seasonality of the species and support the design of tailored management strategies that address transboundary threats to an Important Marine Mammal Area.

Tidewater glacier retreat in Antarctica: The table is set for fast-growing opportunistic species, is it?

The rapid warming of the West Antarctic Peninsula (WAP) is causing an important expansion of marine coastal areas due to glacier retreat. These new ice-free areas offer additional habitats for the colonization of benthic species in areas formerly occupied by ice. The establishment of benthic species can represent important negative feedback to the warming process due to the new carbon fixed and stored. Opportunistic, fast-growing, and high turnover species are expected to colonize these new emerging areas. At Potter Cove, the glacier retreat has opened wide areas of soft bottoms, which provides an excellent study area to assess the colonization process and the success of opportunistic species. Here, we examined the population response of the opportunistic soft coral Malacobelemnon daytoni species in the soft bottom area of Potter Cove with different exposure times due to glacier retreat. Our results show a significant variation of M. daytoni population among the sampled areas in terms of presence, abundances, and distribution. In the long-term ice-free areas, opened for more than 60 years, we observed a ~20-fold increase of M. daytoni densities within just 15 years. However, this extraordinary population outburst was not observed in the newer ice-free areas (≤15 years). We registered very low densities in areas of 15 years and no colonies in areas with 10 years of open sea conditions. These were unexpected results based on colonization capabilities showed by the species and habitat suitability of the new areas. Indeed, using Species Distribution Models (SDMs) we also obtained contrasting outputs. SDMs based on long-term areas presence data predicted high habitat suitability and the potential presence of the species in the newer areas. However, when based on newer and older areas data, SDMs showed low habitat suitability and potential absence of the species in the newer areas. This work suggests that species that can be considered as fast and efficient colonizers, could not perform in that way under certain conditions. This deepens the current knowledge on species natural history and environmental relationships, especially to improve our prediction capabilities under changing environmental conditions.

High extinction risk and limited habitat connectivity of Muñoa’s pampas cat, an endemic felid of the Uruguayan Savanna ecoregion

Muñoa’s pampas cat (recently proposed to be a distinct species, Leopardus munoai) is a small felid that is endemic to the Uruguayan Savanna ecoregion (encompassing southern Brazil, north-eastern Argentina and Uruguay). Previous studies have suggested that it is threatened, but its conservation assessment has been hampered by the scarcity of data on its ecology, including spatial distribution, population size, and connectivity. To address these issues, we developed current spatial distribution models and used them to: (i) identify the environmental variables affecting L. munoai habitat suitability; (ii) generate estimates of population size to assess its conservation status based on IUCN criteria; (iii) estimate habitat suitability in protected areas; (iv) identify potential paths of connectivity among protected areas and sites of confirmed occurrence; and (v) assess the proportion of the estimated connectivity paths that overlap with threatened areas (based on future threat projections). Our results indicated higher habitat suitability in the central area of the species’ distribution. All estimates (based on different demographic assumptions) indicated that L. munoai should be categorized in one of the IUCN threatened categories. Worryingly, several estimates indicated that it may be Critically Endangered. Only 0.73 % of its high-suitability landscape is presently protected, and connectivity among most protected areas and occurrence records was low. Additionally, areas with estimated connectivity among occurrence records mostly overlapped with regions with a high level of future habitat loss threat (92.46 %), highlighting the urgent need for an international approach to ensure the long-term survival of this elusive felid.

Population genetic structure of sharpbelly Hemiculter leucisculus (Basilesky, 1855) and morphological diversification along climate gradients in China.

Sharpbelly Hemiculter leucisculus (Basilewski, 1855) is a small, widespread, and native cyprinid fish with prominent habitat suitability and high invasive potential and is becoming the dominant species in freshwater ecosystems under intensified environmental disturbances. But how H. leucisculus acclimates to extremely heterogeneous environments remains unclear. In current study, the genetic structure of H. leucisculus was analyzed using Bayesian phylogenetic inference, haplotype network, and STRUCTURE base on cytb gene across 18 populations spanning 20 degrees of latitude and 18 degrees of longitude in China. The morphological diversification of body size and shape for H. leucisculus along the climate gradient was studied. The results showed that the 18 H. leucisculus populations were divided into 3 clusters: one cluster mainly from Huanghe River Basin, another cluster mainly from Yangzi River Basin, and H cluster containing Hainan and Beihai populations. The fish from southern populations were deeper bodied while individuals from northern populations were more slender. Inland individuals were more streamlined while coastal individuals were of deeper body. The partial Mantel test predicts that the potential mechanism underlining the intraspecies morphological diversification along climate gradients is primarily the divergent selection pressures among different environments, while genetic variation had less contribution to morphological differentiation. The formation of the Nanling Mountain Range could drive genetic differentiation between Beihai population and those from Yangzi River Basin. The present results highlight strong selective pressures of climate on widespread species and enrich morphological differentiation basis of acclimation for species with high habitat suitability and invasive potential.

Drivers of Spatial Distributions of Basking Shark (Cetorhinus maximus) in the Southwest Pacific

Basking sharks (Cetorhinus maximus) were widely reported throughout New Zealand waters. Once commonly observed, and sometimes in large numbers, basking sharks are now infrequently reported. Basking shark observations are known to be highly variable across years, and their distribution and occurrence have been shown to be influenced by environmental predictors such as thermal fronts, chl-a concentration, and the abundance of prey (zooplankton). Little is known of basking sharks in the South Pacific and more information on distribution, habitat use, and migratory patterns is required to better understand the species’ regional ecology. Here, we used bootstrapped Habitat Suitability Models [HSM, ensembled from Boosted Regression Tree (BRT) and Random Forest (RF) models] to determine the drivers of basking shark distribution, predict habitat suitability and estimated uncertainty in the South Pacific for the first time. High−resolution environmental (1 km2 grid resolution) and biotic data, including inferred prey species, and all available basking shark records across New Zealand’s Exclusive Economic Zone (EEZ) were included in the ensemble HSMs. The most influential driver of modeled basking shark distribution was vertical flux of particulate organic matter at the seabed, which may indicate higher levels of primary production in the surface ocean and higher prey density in the mesopelagic zone and at the seafloor. The BRT and RF models had good predictive power (AUC and TSS > 0.7) and both models performed similarly with low variability in the model fit metrics. Areas of high basking shark habitat suitability included the east and west coasts of the South Island, Puysegur Ridge, and Auckland Island slope. The outputs produced here could be incorporated into future management framework for assessing threat and conservation needs (e.g., spatially explicit risk assessment) for this regionally protected species, as well as providing guidance for future research efforts (e.g., areas of interest for sampling).

Modelling the Spatial Distribution of ASF-Positive Wild Boar Carcasses in South Korea Using 2019-2020 National Surveillance Data.

Simple SummarySince African swine fever (ASF) virus in wild boar populations can spill over to domestic pigs, it is crucial to understand the disease determinants in the wild compartment. However, the imperfect detection sensitivity of wild boar surveillance jeopardizes our ability to understand ASF spatial distribution. In this study, we used national surveillance data of ASF in wild boars collected in the Republic of Korea from 2019–2020 to model the spatial distribution of ASF-positive carcasses for two successive study periods associated with different surveillance intensity. The model allowed us to identify disease risk factors in the Republic of Korea, determine the spatial distribution of the risk of ASF, and estimate the sensitivity of surveillance. The outputs of this study are relevant to policy makers for developing and improving risk-based surveillance programs for ASF in wild boars.In September 2019, African swine fever (ASF) was reported in South Korea for the first time. Since then, more than 651 ASF cases in wild boars and 14 farm outbreaks have been notified in the country. Despite the efforts to eradicate ASF among wild boar populations, the number of reported ASF-positive wild boar carcasses have increased recently. The purpose of this study was to characterize the spatial distribution of ASF-positive wild boar carcasses to identify the risk factors associated with the presence and number of ASF-positive wild boar carcasses in the affected areas. Because surveillance efforts have substantially increased in early 2020, we divided the study into two periods (2 October 2019 to 19 January 2020, and 19 January to 28 April 2020) based on the number of reported cases and aggregated the number of reported ASF-positive carcasses into a regular grid of hexagons of 3-km diameter. To account for imperfect detection of positive carcasses, we adjusted spatial zero-inflated Poisson regression models to the number of ASF-positive wild boar carcasses per hexagon. During the first study period, proximity to North Korea was identified as the major risk factor for the presence of African swine fever virus. In addition, there were more positive carcasses reported in affected hexagons with high habitat suitability for wild boars, low heat load index (HLI), and high human density. During the second study period, proximity to an ASF-positive carcass reported during the first period was the only significant risk factor for the presence of ASF-positive carcasses. Additionally, low HLI and elevation were associated with an increased number of ASF-positive carcasses reported in the affected hexagons. Although the proportion of ASF-affected hexagons increased from 0.06 (95% credible interval (CrI): 0.05–0.07) to 0.09 (95% CrI: 0.08–0.10), the probability of reporting at least one positive carcass in ASF-affected hexagons increased from 0.49 (95% CrI: 0.41–0.57) to 0.73 (95% CrI: 0.66–0.81) between the two study periods. These results can be used to further advance risk-based surveillance strategies in the Republic of Korea.

Biased baselines? Differences in manual and computer-based modelling of blue-winged teal (Spatula discors) habitat suitability

Assessing wildlife habitat suitability has been an important tool in species conservation for generations of wildlife managers, despite changes in technology and theoretical frameworks. The goal of this study was to quantify differences in habitat suitability indices (HSIs) for blue-winged teal derived from our re-creation of traditional paper-based outputs and GIS-based outputs using the same inputs and to determine how HSIs for blue-winged teal would respond to fine-scale applications in Miquelon Lake Provincial Park, Canada. The subsequent models assessed the four original variables presented by the 1985 USFWS model: wetland density, wetland area, horizontal cover, and proximity to wetlands for three components of breeding habitat including pair bonding, nesting, and brood rearing. For a subset of GIS models, vertical cover was also incorporated into our analyses to determine its applicability in the model’s assessment of aerial predation risk for blue-winged teal. The paper-based model consistently produced higher habitat suitability scores when compared to the GIS model, with only the brood-rearing model being slightly lower. When vertical cover was included in the GIS model either by itself or combined with horizontal cover, the area of high suitability habitat was reduced to 0% and ∼3%, respectively. Results revealed that the species did not show a special preference to high or moderately suitable habitats. Given the overestimation of habitat suitability at all breeding stages for blue-winged teal, the comparative utility of the actual HSI scores derived manually from such models are limited; however, the long-term ecological insights into model inputs are invaluable when integrated with emerging spatial data for computer-based habitat modelling.

There will be conflict – agricultural landscapes are prime, rather than marginal, habitats for Asian elephants

AbstractMisconceptions about species’ ecological preferences compromise conservation efforts. Whenever people and elephants share landscapes, human–elephant conflicts (HEC) occur in the form of crop raiding, elephant attacks on people and retaliatory actions from people on elephants. HEC is considered the main threat to the endangered Asian elephant Elephas maximus. Much of HEC mitigation in Asia is based on rescuing elephants from conflict areas and returning them to nature, for example, by means of ‘problem elephant’ translocation. Here, we used two independent and extensive datasets comprising elephant GPS telemetry and HEC incident reports to assess the relationship between elephant habitat preferences and the occurrence of HEC at a broad spatial scale in Peninsular Malaysia. Specifically, we assessed (a) the habitat suitability of agricultural landscapes where HEC incidents occur and (b) sexual differences in habitat preferences with implications for HEC mitigation and elephant conservation. We found strong differences in habitat use between females and males and that the locations of HEC incidents were areas of very high habitat suitability for elephants, especially for females. HEC reports suggest that in Peninsular Malaysia females are involved in more crop damage conflicts than males, whereas males are more prone to direct encounters with people. Our results show that human‐dominated landscapes are prime elephant habitat, and not merely marginal areas that elephants use in the absence of other options. The high ecological overlap between elephants and people means that conflict will continue to happen when both species share landscapes. HEC mitigation strategies, therefore, cannot be based on elephant removal (e.g. translocation) and need to be holistic approaches that integrate both ecological and human social dimensions to promote tolerated human–elephant coexistence.