Habitat Availability Research Articles

Reproductive and persistence strategy of the liverwort Arnellia fennica after the last glaciation in the area of disjunction in Central Europe (Polish Tatra Mountains, carpathians)

The liverwort Arnellia fennica has a circumarctic distribution with disjunct and scarce localities in the Alps, Carpathians, and Pyrenees. Within the Carpathians, it is only known from the Tatra Mountains (in Poland), where so far only four occurrences have been documented in the forest belt of the limestone part of the Western Tatras. The species is considered a tertiary relict, which owes its survival during the last glaciation period to low-lying locations in areas not covered by ice. Previously, it has been demonstrated that this plant does not produce gemmae in the Tatra Mountains, nor does it reproduce sexually, hence it has not spread in this massif despite the high availability of potential habitats. These studies address the following questions: (1) why A. fennica, an arctic-alpine species, has only been found at low elevations in the Tatra Mountains so far, (2) what were the possibilities of its survival during the glaciation period as verified based on the latest paleoglaciological map, (3) how this species persists in the Tatras and why it remains a rare plant. As a result, nine additional new occurrences were found, bringing the total to 13 throughout the massif. Some of the sites were found in the high mountain area. For the first time, the production of gemmae in the Tatra population of A. fennica was observed and documented, along with the presence of male specimens of this dioecious species. Genetic studies have shown that individuals from all three groups of sites are genetically homogeneous, indicating a lack of sexual reproduction. The only way of dispersal for A. fennica in the Tatras is through propagule production. The uniqueness and specificity of these structures have been described, which differ significantly from the common model known in liverworts. The rarity of the species in the Tatra massif is attributed to the inefficient mode of vegetative reproduction and the absence of sexual reproduction. Paleoglaciological analysis of all montane sites (historical and new) of A. fennica showed that half were located in areas covered by glaciers. The hypothesis of this liverwort’s survival during the glaciation period, at lower elevations, should be rejected. In light of the new data obtained, montane localities should be considered as secondary, which could have arisen after the glacier retreated only from high-mountain populations producing propagules transported downhill.

The impact of climate change on the nearly threatened taxa Elaeocarpus munroi (Wight) Mast. inhabiting in the forest of the Western Ghats.

Elaeocarpus munroi (Wight) Mast., commonly called Nilgiri Marble Tree, is a nearly threatened taxa as per the International Union for Conservation of Nature (IUCN). This species is endemic to the southern Western Ghats. The present study examines its spatial distribution across the sky islands of the Western Ghats under different climate scenarios (1900-2100) using four shared socioeconomic pathways (SSPs). Species distribution modeling was conducted using ensemble techniques in R, along with various ecological niche modeling algorithms. The present study examines the past, present, and future distribution of E. munroi across the Western Ghats. Historical projections indicated that the highest habitat suitability areas for the species were in the southern and central regions of the Western Ghats. The model projections for the species from 2021 to 2100 indicate a noticeable northward shift in habitat suitability. As climate scenarios change, the central and northern regions of the Western Ghats are becoming more suitable for it. This anticipated shift poses a potential threat to the species persistence, as the availability of suitable habitats decline in its historically preferred southern range. This range shift, coupled with E. munroi's near-threatened status, emphasizes the urgent need for its conservation interventions. This study pioneers efforts to understand and mitigate the impacts of climate change on E. munroi. This, in turn, offers a foundation for developing targeted conservation strategies in this ecologically important region. The findings highlight the importance of integrating climate change into conservation planning and management practices to safeguard the future of species like E. munroi within the broader ecosystem they inhabit. This study contributes to the growing body of research addressing the complex interplay between climate change and biodiversity conservation, thereby underscoring the need for collaborative and proactive approaches to mitigate the adverse effects of climate change.

Habitat use and co-occurrence of two species of tody-tyrant, Hemitriccus (Aves: Rhynchocyclidae) in a fragment of montane forest in north-eastern Brazil

ABSTRACT The availability of appropriate habitats and their connectivity are important determinants of the distribution of animal species. In the present study, the influence of environmental covariates on the habitat use of two tody-tyrants (Hemitriccus margaritaceiventer and Hemitriccus mirandae) was verified using single-season occupancy modelling. The co-occurrence patterns of the two species were also analysed using conditional occupancy modelling. The data were collected in remnants of montane forest in north-eastern Brazil using the point count method, with samples being obtained in both dry (November to January) and rainy (May and June) seasons. Four types of environmental covariates were evaluated: the season, elevation, parameters of vegetation structure, and level of environmental degradation. The occupancy of H. margaritaceiventer was influenced primarily by elevation, whereas that of H. mirandae was influenced primarily by tree diameter. These results reflect a predictable relationship between the species and the respective covariates, in particular in the case of H. mirandae. Occupancy and detection probabilities did not vary systematically between seasons. The conditional occupancy indicated that the two species co-occur through an aggregative relationship. The co-occurrence pattern identified here may be attributable to the fragmentation and environmental degradation of the study area, which may have influenced the habitat preferences of the species. These findings provide a better understanding of how the two species select and use their habitats, particularly by showing the effects of topography and vegetation on tody-tyrants. This information will be especially important for developing effective conservation strategies for H. mirandae, a vulnerable species with a restricted geographic distribution.

Insect Decline-Evaluation of Potential Drivers of a Complex Phenomenon.

The decline of insects is a global concern, yet identifying the factors behind it remains challenging due to the complexity of potential drivers and underlying processes, and the lack of quantitative historical data on insect populations. This study assesses 92 potential drivers of insect decline in West Germany, where significant declines have been observed. Using data from federal statistical offices and market surveys, the study traces changes in landscape structure and agricultural practices over 33 years. Over the years, the region underwent major landscape changes, including reduced cropland and grassland and increased urbanization and forest areas. Potential detected drivers of insect decline include: (1) urban expansion, reducing insect habitats as urban areas increased by 25%; (2) intensified grassland management; (3) shifts in arable land use towards bioenergy and feed crop cultivation, particularly corn, driven by dairy farming intensification and renewable energy policies. While the toxic load of pesticide application has decreased, land-use changes, most likely driven by market demands and shifts in national and EU policies, have reduced habitat availability and suitability for insects. This study highlights how these landscape and land management changes over the past 33 years align with the observed decline in insect biomass in the region.

Factors affecting population density and colonization success of two non-native beetle species with different breeding/life-history strategies

IntroductionBark and longhorn beetles have become of increasing concern as invasive pests as they are transported across the globe. The larch bark beetle Ips cembrae and the larch longhorn beetle Tetropium gabrieli are two species that have recently established in Scandinavia. We asked the following questions for both I. cembrae and T. gabrieli: (i) How does habitat availability affect the relative population density? (ii) How is the colonization probability related to the relative population density? (iii) What is the relationship between relative population densities of the beetles and enemy pressure?MethodsThe relative population density of the two beetle species were assessed with two pheromone-baited traps for each beetle species in 36 pure larch stands distributed in southern Sweden and Denmark. In addition, colonization success was recorded on five cut larch trees in 30 of the 36 larch stands.ResultsIps cembrae was trapped in 19 stands and had colonized cut trees in two stands, whereas Tetropium gabrieli was trapped in 18 stands and had colonized cut trees in 12 stands. Both species showed a positive relationship between the relative population density and the probability of colonization of the cut trees. For I. cembrae a higher population size was required for colonization than for T. gabrieli. The relative population density of both species was positively related to the amount of habitat.DiscussionThe difference in the population size required for colonization between the two studied species might be explained by their different reproductive strategies. The results are discussed in terms of host location and mate finding, and predation pressure.

OBSERVATIONS ON THE WINTERING OF WHITE-STORK CICONIA CICONIA (LINNAEUS, 1758) FROM SOUTH-EASTERN PART OF TÜRKİYE

Between the December 2003 and January 2023 periods, 119 individuals of White-stork Ciconia ciconia (Linnaeus, 1758) have been recorded during winter seasons that covering only December and January months. White-storks determined between Diyarbakır and Batman provinces from 12 different locations and also nearly all of the records obtained within the boundaries of the Bismil Plain IBA’s between Diyarbakır and Batman provinces. The wintering of species in this part of Türkiye and Diyarbakır province have been firstly documented. The availability of suitable habitat's together with food possibilities and mild climate conditions may have been supports the population increase in the area during all year round. This study showed that White-storks have found the favourable conditions for wintering in our region and have now started to wintering. Monitoring of the wintering population in the region is recommended for evaluate changes in size of population and range expansion of species in the area by a comprehensive field study in this part of country.

Population Viability of an Endangered Population of Greater Gliders (Petauroides volans) and Management Implications

The population of the endangered southern greater glider (Petauroides volans) is rapidly declining across coastal lowlands in New South Wales, Australia. Here, we focus on a typical coastal lowland glider population in Seven Mile Beach National Park, New South Wales, that is declining primarily due to habitat fragmentation. This study aimed to assess the population’s status and viability in order to guide conservation efforts. Using the double-observer distance sampling method, we estimated the population size to be 347 gliders, with a density of 0.46 gliders/ha. Population viability analysis revealed a high extinction risk, with only a 1% chance of survival over the next 50 years. Fire was identified as the primary threat, followed by a low effective population size and inbreeding. The most effective conservation strategy involved genetic reinforcement through possible translocation and the installation of up to 50 nest boxes to improve habitat (hollow) availability.

Impact of Climatic Factors on the Temporal Trend of Malaria in India from 1961 to 2021.

Malaria remains a significant public health problem in India. Although temperature influences Anopheline mosquito feeding intervals, population density, and longevity, the reproductive potential of the Plasmodium parasite and rainfall influence the availability of larval habitats, and evidence to correlate the impact of climatic factors on the incidence of malaria is sparse. Understanding the influence of climatic factors on malaria transmission will help us predict the future spread and intensification of the disease. The present study aimed to determine the impact of temporal trend of climatic factors such as annual average maximum, minimum, mean temperature, and rainfall on the annual incidence of malaria cases in India for a period of 61 years from 1961 to 2021 and relative humidity for a period of 41 years from 1981 to 2021. Two different analyses were performed. In the first analysis, the annual incidence of malaria and meteorological parameters such as annual maximum, minimum, and mean temperature, annual rainfall, and relative humidity were plotted separately in the graph to see if the temporal trend of climatic factors had any coherence or influence over the annual incidence of malaria cases. In the second analysis, a scatter plot was used to determine the relationship of the incidence of malaria in response to associated climatic factors. The incidence of malaria per million population was also calculated. In the first analysis, the annual malaria cases showed a negative correlation of varying degrees with relative humidity, minimum, maximum, and mean temperature, except rainfall, which showed a positive correlation. In the second analysis, the scatter plot showed that the rainfall had a positive correlation with malaria cases, and the rest of the climatic factors, such as temperature and humidity, had negative correlations of varying degrees. Out of the total 61 years studied, in 29 years, malaria cases increased more than 1000 square root counts when the minimum temperature was at 18-19 °C; counts also increased over a period of 33 years when the maximum temperature was 30-31 °C, over 37 years when the mean temperature was 24-25 °C, over 20 years when the rainfall was in the range of 100-120, and over a period of 29 years when the relative humidity was at 55-65%. While the rainfall showed a strong positive correlation with the annual incidence of malaria cases, the temperature and relative humidity showed negative correlations of various degrees. The increasing temperature may push the boundaries of malaria towards higher altitude and northern sub-tropical areas from the southern peninsular region. Although scanty rainfall reduces the transmission, increases in the same would increase the malaria incidence in India.

Biodiversity monitoring with intelligent sensors: An integrated pipeline for mitigating animal-vehicle collisions

Transports of people and goods contribute to the ongoing 6th mass extinction of species. They impact species viability by reducing the availability of suitable habitat, by limiting connectivity between suitable patches, and by increasing direct mortality due to collisions with vehicles. Not only does it represent a threat for some species conservation capabilities, but animal vehicle collisions (AVC) is also a threat for human safety and security in transport and has a massive cost for transport infrastructure (TI) managers and users. Using the opportunities offered by the increasing number of sensors embedded into TI and the development of their digital twins, we developed a framework aiming at managing AVC by mapping the collision risk between trains and ungulates (roe deer and wild boar) thanks to the deployment of a camera trap network. The proposed framework uses population dynamic simulations to identify collision hotspots and assist with the design of sensors deployment. Once sensors are deployed, the data collected, here photos, are processed through deep learning to detect and identify species at the TI vicinity. Then, the processed data are fed to an abundance model able to map species relative abundance around the TI as a proxy of the collision risk. We implement the framework on an actual section of railway in south-western France benefiting from a mitigation and monitoring strategy. The implementation thus highlighted the technical and fundamental requirements to effectively mainstream biodiversity concerns in the TI digital twins. This would contribute to the AVC management in autonomous vehicles thanks to connected TI.

Agricultural land use and reproductive behaviour constrain responses to summer thermal stress in a large herbivore

Agricultural land use and climate change are major global threats to terrestrial biodiversity. However, their interactive effects on synanthropic species are only recently being addressed. Behavioural plasticity is the most likely candidate mechanism for coping with rapid environmental change, yet behavioural adjustments may be insufficient when multiple anthropogenic pressures, such as human land-use and rising temperatures, coincide with strong life-history constraints. We investigated how agricultural land use shaped the availability of thermal refuge and mediated responses to high temperatures during the mating season in roe deer (Capreolus capreolus), a large herbivore that is common in most European agricultural landscapes. We demonstrated that woodland provided more efficient thermal refuge than anthropogenic vegetation such as hedges or tall crops. The combination of high temperatures, agricultural land-use and reproductive constraints were dealt with differently by males and females. Females adjusted their habitat use and activity patterns to limit exposure to high temperatures, resulting in a greater loss in the availability of efficient cover habitat for females with little access to woodland. Males, however, did not modify their habitat use, but strongly decreased activity and distance travelled on hot days, probably due to strong reproductive constraints. We show that the extent to which behavioural plasticity mitigates the effects of high temperatures is context-dependent and may not always suffice in anthropized landscapes where thermal buffering habitats are rare. Restoring woodland patches and hedges, while considering how climate change modifies the use of substitute habitats shaped by human activities, will be key in promoting species' resilience within agricultural areas.

First Report of the Thermophilic Thalassoma Pavo (Linnaeus, 1758) on the Central Adriatic Coast of Italy, in Abruzzo

The Trabocchi Coast in the Chieti district of the mid-Adriatic (Italy) is one of the few rocky areas within the General Fisheries Commission GSA 17, alongside Mount Conero (Ancona 43°00′01″ N 13°52′13″ E) and the small San Nicola Rock (Ascoli Piceno; 43°32′0″ N 13°36′0″ E). This coastline is known for its biodiversity-rich bays, inlets, and submerged cliffs. Since 2015, annual biodiversity surveys have been conducted in the area, focusing on marine species richness and the identification of non-native species. In September 2024, a juvenile ornate wrasse (Thalassoma pavo) was documented for the first time in the middle Adriatic during an underwater visual survey at Trabocco Punta Torre, a key site along the Trabocchi Coast near artificial and biogenic reefs. This record extends the known distribution of T. pavo, a thermophilic species previously reported only along the southern Adriatic coast of Puglia. This is the first confirmed sighting on the middle and northern Adriatic coast of Italy. The discovery highlights the importance of ongoing biodiversity monitoring to track changes in marine ecosystems, particularly as the Adriatic Sea faces environmental shifts linked to climate warming. The presence of T. pavo in this area suggests the potential for the species to establish populations in previously uninhabited northern regions. Further research is needed to explore the role of biotic and abiotic factors—such as water temperature, current patterns, and habitat availability—in the survival and potential reproduction of T. pavo in the middle Adriatic. The observation contributes to the broader understanding of the meridionalization process in the Adriatic Sea, where rising water temperatures are facilitating the northward expansion of thermophilic species. Continuous monitoring is recommended to assess the long-term viability of T. pavo populations in the Adriatic Sea and better predict the impacts of ongoing climate change on marine biodiversity.

A Trap-Vaccinate-Release Protocol for Immunization of Skunks and Additional Rabies Vectors Against Rabies.

Oral vaccination of wildlife against rabies via the distribution of vaccine-laden baits is used widely as a management tool in Europe and North America. Over the past several decades, successful programs have targeted important reservoirs, including coyotes, foxes, raccoon dogs, and raccoons, for prevention and control. However, other species (e.g., skunks) or certain habitats (e.g., urban) may be less amenable to oral vaccination, requiring consideration of additional strategies. Trap-vaccinate-release (TVR) is one alternate method that entails the use of live traps to capture targeted wildlife. Traps are distributed along grids in suitable, accessible habitats. Captured animals are identified by tagging, vaccinated parenterally with an inactivated commercial vaccine, sexed, aged, weighed, and released at the site of capture. Since 2001, cross-species transmission of rabies virus from bats to mesocarnivores, such as skunks, has been detected in Flagstaff, Arizona. During the past two decades, TVR has been used as a safe and effective method to prevent and control rabies during such events in this region.

Orchards and paddy differentially impact rock outcrop amphibians: Insights from community- and species-level responses.

With agricultural demands increasing globally, determining the nature of impacts of different forms of agriculture on biodiversity, especially for threatened vertebrates and habitats, is critical to inform land management. This is especially true for open ecosystems such as the natural rock outcrops and amphibians, both of which are threatened by land-use change. Lateritic plateaus of the northern Western Ghats are rock outcrop ecosystems harboring endemic biodiversity. Since most of these plateaus are located outside protected areas and officially classified as wastelands, they are rapidly lost due to multiple human pressures, including agriculture. We compared amphibian composition, diversity, and species responses across these rocky plateaus (hereafter plateaus), orchards, and rice paddy in the Western Ghats-Sri Lanka biodiversity Hotspot, India. We sampled 50 belt transects across four geographically separated plateaus, covering three land-use classes in three of the plateaus, and recorded information on amphibians and their microhabitats. Each transect was sampled four times across the rainy season. We compared responses of amphibians across three land-use categories at the community level using Hill numbers, beta-diversity measures, and nonmetric multidimensional scaling, and at the species level using joint species distribution modeling. Converting plateaus to paddy and orchards significantly altered microhabitat availability by reducing the rock pool habitat availability in paddy and orchards, and increased deep, water-submerged areas and grass cover in paddy. Conversion to paddy mostly had species- and community-level impacts, that is, lowered species occurrence of certain species, lowered species richness, and more nested communities, whereas conversion to orchards mostly had species-level impacts, that is, lowered species occurrence, highlighting that different forms of agriculture have varying impacts on amphibians that can be determined by examining community- and species-level effects simultaneously. Using only community- or species-level metrics would not have unraveled these impacts completely. We show that large rock pools are critical microhabitats for frogs, most likely serving as refugia and protecting frogs from desiccation during dry spells in monsoons. Since Indian lateritic plateau habitats in low elevations are rapidly being converted to orchards, efforts are needed to conserve them in partnership with local communities, the custodians of these habitats.

Effects of Peromyscus spp. (Rodentia: Cricetidae) presence, land use, and ecotone on Ixodes scapularis (Acari: Ixodidae) ecology in an emergent area for tick-borne disease.

As the range of Ixodes scapularis Say expands, host abundance and land use can play important roles in regions where ticks and their associated pathogens are emerging. Small mammal hosts serve as reservoirs of tick-borne pathogens, with Peromyscus leucopus Rafinesque often considered a primary reservoir. A sympatric species Peromyscus maniculatus Wagner is also a competent reservoir and is notoriously difficult to differentiate from P. leucopus. Anthropogenic land use can alter host and habitat availability, potentially changing tick exposure risk. We tested the hypotheses that tick infestation and pathogen prevalence differ between the two Peromyscus spp. and that host-seeking I. scapularis density and pathogen prevalence differ across land use and ecotone gradients. We live trapped small mammals and collected ticks across 3 land-use classifications and ecotones in Maine, an emergent area for tick-borne disease. We tested each small mammal and tick sample for Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti. While both Peromyscus spp. serve as hosts for immature ticks, P. leucopus exhibited a higher tick infestation frequency and intensity. We did not detect any significant difference in pathogen infection prevalence between the two species. The density of I. scapularis nymphs and the density of infected nymphs did not differ significantly between land-use types, though did differ across ecotones. We also noted a significant north/south gradient, with higher tick densities and pathogen prevalence at the southern end of the study area. Our study highlights the potential variability in tick density and pathogen prevalence across fine spatial scales within an emerging region for tick-borne disease.

Interpopulation and seasonal variations in habitat and microhabitat use of Vipera ammodytes

Despite the abundant data on habitat use of Vipera ammodytes, most studies are purely descriptive, merely listing the habitats in which the species is most often found. More complete studies evaluating the habitat preference of the species are lacking. The intraspecific variation (i.e., interpopulation or seasonal) in habitat and microhabitat utilization of the species also remains a poorly studied topic. In the current study, we assessed the general patterns of habitat and microhabitat use of V. ammodytes and their interpopulation and seasonal variations, based on habitat/microhabitat availability. To achieve that, we studied five different populations along a latitudinal gradient in western Bulgaria. In all of the studied areas, V. ammodytes showed a clear preference for various stony and rocky habitats and microhabitats, overgrown with herbaceous and shrub vegetation, while it avoided bare habitats, dark deciduous forests as well as cultivated agricultural lands. There were clear interpopulation and seasonal variations in habitat and microhabitat preference and spatial niche utilization. Our results suggest that habitat and microhabitat use of V. ammodytes depend on a combination of many factors such as season, locally specific characteristics like habitat structure and availability, population dynamics, food availability, physical and microclimatic conditions, and possibly on the extent of the interspecific competition.

Enhancing high-resolution forest stand mean height mapping in China through an individual tree-based approach with close-range lidar data

Abstract. Forest stand mean height is a critical indicator in forestry, playing a pivotal role in various aspects such as forest inventory, sustainable forest management practices, climate change mitigation strategies, monitoring of forest structure changes, and wildlife habitat assessment. However, there is currently a lack of large-scale, spatially continuous forest stand mean height maps. This is primarily due to the requirement of accurate measurement of individual tree height in each forest plot, a task that cannot effectively be achieved by existing globally covered, discrete footprint-based satellite platforms. To address this gap, this study was conducted using over 1117 km2 of close-range light detection and ranging (lidar) data, which enables the measurement of individual tree heights in forest plots with high precision. Apart from lidar data, this study incorporated spatially continuous climatic, edaphic, topographic, vegetative, and synthetic aperture radar data as explanatory variables to map the tree-based arithmetic mean height (ha) and weighted mean height (hw) at 30 m resolution across China. Due to limitations in obtaining the basal area of individual tree within plots using uncrewed aerial vehicle (UAV) lidar data, this study calculated the weighted mean height through weighting an individual tree height by the square of its height. In addition, to overcome the potential influence of different vegetation divisions at a large spatial scale, we also developed a machine-learning-based mixed-effects (MLME) model to map forest stand mean height across China. The results showed that the average ha and hw across China were 11.3 and 13.3 m with standard deviations of 2.9 and 3.3 m, respectively. The accuracy of mapped products was validated utilizing lidar and field measurement data. The correlation coefficient (r) for ha and hw ranged from 0.603 to 0.906 and 0.634 to 0.889, while the root mean square error (RMSE) ranged from 2.6 to 4.1 and 2.9 to 4.3 m, respectively. Comparing with existing forest canopy height maps derived using the area-based approach, it was found that our products of ha and hw performed better and aligned more closely with the natural definition of tree height. The methods and maps presented in this study provide a solid foundation for estimating carbon storage, monitoring changes in forest structure, managing forest inventory, and assessing wildlife habitat availability. The dataset constructed for this study is publicly available at https://doi.org/10.5281/zenodo.12697784 (Chen et al., 2024).

Food Habits of Eriphia Verrucosa (Eriphiidae) and Pachygrapsus marmoratus (Grapsidae) in the Mediterranean Coast of Eastern Libya in Sosa

The current study aims to determine the type and abundance of food for two species of crabs, Pachygrapsus marmoratus and Eriphia verrucosa, that inhabit the rocky beaches in the south. Mediterranean coast. A total of 40 crabs of each species collected during 2022 were used. We found that P. marmoratus and Eriphia verrucosa are carnivores, meaning they feed on what is available in their environment. Gastric fullness was determined. Food availability in habitats. The abundance of food in the stomach varies according to varieties, but the general trend was molluscas and crustaceans > Cnidarians > Algae > Seaweed > Fish; this is for the Pachygrapsus crab. Marmoratus, but the general trend was molluscas and cnidarians > And fish > Seaweed > And crustaceans > And algae. This is for the crab Eriphia verrucosa. This study provides information on the abundance and type of food by examining the stomach and knowing the percentage of its fullness and the type and abundance of food in the stomach.

The effects of seasonal human mobility and Aedes aegypti habitat suitability on Zika virus epidemic severity in Colombia.

The Zika virus epidemic of 2015-16, which caused over 1 million confirmed or suspected human cases in the Caribbean and Latin America, was driven by a combination of movement of infected humans and availability of suitable habitat for mosquito species that are key disease vectors. Both human mobility and mosquito vector abundances vary seasonally, and the goal of our research was to analyze the interacting effects of disease vector densities and human movement across metapopulations on disease transmission intensity and the probability of super-spreader events. Our research uses the novel approach of combining geographical modeling of mosquito presence with network modeling of human mobility to offer a comprehensive simulation environment for Zika virus epidemics that considers a substantial number of spatial and temporal factors compared to the literature. Specifically, we tested the hypotheses that 1) regions with the highest probability of mosquito presence will have more super-spreader events during dry months, when mosquitoes are predicted to be more abundant, 2) regions reliant on tourism industries will have more super-spreader events during wet months, when they are more likely to contribute to network-level pathogen spread due to increased travel. We used the case study of Colombia, a country with a population of about 50 million people, with an annual calendar that can be partitioned into overlapping cycles of wet and dry seasons and peak tourism and off tourism seasons that drive distinct cyclical patterns of mosquito abundance and human movement. Our results show that whether the first infected human was introduced to the network during the wet versus dry season and during the tourism versus off tourism season profoundly affects the severity and trajectory of the epidemic. For example, Zika virus was first detected in Colombia in October of 2015. Had it originated in January, a dry season month with high rates of tourism, it likely could have infected up to 60% more individuals and up to 40% more super-spreader events may have occurred. In addition, popular tourism destinations such as Barranquilla and Cartagena have the highest risk of super-spreader events during the winter, whereas densely populated areas such as Medellín and Bogotá are at higher risk of sustained transmission during dry months in the summer. Our research demonstrates that public health planning and response to vector-borne disease outbreaks requires a thorough understanding of how vector and host patterns vary due to seasonality in environmental conditions and human mobility dynamics. This research also has strong implications for tourism policy and the potential response strategies in case of an emergent epidemic.

Habitat use and movement patterns of broad-snouted caimans (Caiman latirostris) in an impacted Atlantic forest environment in Brazil

BackgroundAnimal habitat use can be influenced by a suite of factors including intraspecific interactions and resource availability. The broad-snouted caiman (Caiman latirostris) is the largest crocodylian species distributed in freshwater environments of the Brazilian Atlantic Forest, where it inhabits many types of human-impacted and preserved habitats. Despite their ability to occupy ecologically different water bodies, little is known about their movement patterns and their habitat use. We investigated the variation in movements and space use of adult caimans relative to sex, body condition, and environmental conditions in northeastern Brazil.MethodsWe conducted long-term capture surveys from 2013 to 2022 and used GPS telemetry from 2021–2022 (n = 12 individuals) to assess movement patterns and home ranges of caimans and their habitat use based on Brownian Bridge Movement Modeling (BBMM) and Generalized Linear Mixed Modeling (GLMM).ResultsFemales ranged farther from reservoir’s forested margins, exploring a greater diversity of habitats during the wet/non-reproductive season. During the dry/reproductive season, females remained close to nesting sites within forest fragments. The body condition of caimans did not change significantly over the wet and dry season, indicating that resources are available year-round. Caimans moved more at night than during daytime, likely due to nocturnal foraging and possibly avoiding periods of increased human activity. Female movement rates were positively associated with rainfall, in a pattern likely linked to nest attendance in the dry season. Male movement was positively correlated with reservoir volume in the wet season, possibly due to increased availability of habitats in comparison to dry periods and to decreased overlap with territories controlled by other males. Home ranges estimated as 95% utilization distributions were relatively small in both sexes, averaging 0.64 km2 (range: 0.001–1.4 km2), as were their core areas estimated as 50% utilization distributions, which averaged 0.12 km2 (range: 0.0003–0.12 km2). Small core areas may indicate that caimans remain most of their time in a specific habitat, suggesting abundant resource availability or territoriality.ConclusionsOur work reveals the complexity of social interactions and how caimans select their habitats in a highly altered environment.

Assessing Potential Spawning and Nursery Habitat Availability in the River Rhine for the Critically Endangered European Sturgeon

ABSTRACTInformation about reproductive habitat and migration pathways is of paramount importance to restore migratory fish species. This study assesses the availability of spawning and nursery habitats for the European sturgeon (Acipenser sturio) in the delta and lower Rhine (covering over 350 river kilometres) as part of a larger feasibility assessment for a future restoration of this critically endangered species. The general approach has three steps: (1) the identification of the species' specific habitat requirements, based on a systematic literature review; (2) the collection and preprocessing of data from two countries, including the 1D and 2D modelling of water depths and flow velocities; and (3) GIS‐based mapping of spawning and nursery habitat. Based on a HSI score of 1, we identify a total of 0.75 km2 as minimal spawning habitat, potentially suitable for approximately 2500 female European sturgeons (one spawning site would use ~300 m2). This is sufficient, as currently, only an estimated maximum number of 750 adults exist. Suitable spawning habitat is mainly located in the German state of North Rhine‐Westphalia, whereas suitable nursery habitat is mainly located in the Netherlands. The availability is, however, significantly reduced by coastal infrastructure (damming) and inland navigation. The insights gained can be used to assess the current suitability of the river Rhine for the species' reintroduction and to identify opportunities for habitat restoration and protection for various life stages. The outcomes thus play an essential role in the conservation of the species. In addition, the modelling approach developed could be applied to other northwestern European rivers. This broader application would allow intercomparison and support decisions about which rivers are best suited for future reintroduction of the critically endangered European sturgeon.