Habitat Preferences Research Articles

Stochastic Character Mapping, Bayesian Model Selection, and Biosynthetic Pathways Shed New Light on the Evolution of Habitat Preference in Cyanobacteria.

Cyanobacteria are the only prokaryotes to have evolved oxygenic photosynthesis paving the way for complex life. Studying the evolution and ecological niche of cyanobacteria and their ancestors is crucial for understanding the intricate dynamics of biosphere evolution. These organisms frequently deal with environmental stressors such as salinity and drought, and they employ compatible solutes as a mechanism to cope with these challenges. Compatible solutes are small molecules that help maintain cellular osmotic balance in high salinity environments, such as marine waters. Their production plays a crucial role in salt tolerance, which, in turn, influences habitat preference. Among the five known compatible solutes produced by cyanobacteria (sucrose, trehalose, glucosylglycerol, glucosylglycerate, and glycine betaine), their synthesis varies between individual strains. In this study, we work in a Bayesian stochastic mapping framework, integrating multiple sources of information about compatible solute biosynthesis in order to predict the ancestral habitat preference of Cyanobacteria. Through extensive model selection analyses and statistical tests for correlation, we identify glucosylglycerol and glucosylglycerate as the most significantly correlated with habitat preference, while trehalose exhibits the weakest correlation. Additionally, glucosylglycerol, glucosylglycerate, and glycine betaine show high loss/gain rate ratios, indicating their potential role in adaptability, while sucrose and trehalose are less likely to be lost due to their additional cellular functions. Contrary to previous findings, our analyses predict that the last common ancestor of Cyanobacteria (living at around 3180 Ma) had a 97% probability of a high salinity habitat preference and was likely able to synthesise glucosylglycerol and glucosylglycerate. Nevertheless, cyanobacteria likely colonized low-salinity environments shortly after their origin, with an 89% probability of the first cyanobacterium with low-salinity habitat preference arising prior to the Great Oxygenation Event (2460 Ma). Stochastic mapping analyses provide evidence of cyanobacteria inhabiting early marine habitats, aiding in the interpretation of the geological record. Our age estimate of ~2590 Ma for the divergence of two major cyanobacterial clades (Macro- and Microcyanobacteria) suggests that these were likely significant contributors to primary productivity in marine habitats in the lead-up to the Great Oxygenation Event, and thus played a pivotal role in triggering the sudden increase in atmospheric oxygen.

Everybody needs good neighbours: movement, habitat use, and conspecific association in a reintroduced mesopredator

As a reintroduction progresses through the establishment, growth, and regulation phases, density-dependent mechanisms increasingly drive population dynamics. This can complicate efforts to reinforce these populations if the translocated individuals (henceforth reinforcers) are excluded, or existing residents become displaced. This is especially pertinent for islands and fenced havens, where immigration is often only possible by translocation. Conspecific associations offer insights into how these density-dependent mechanisms manifest in space and time. We investigated how movement, habitat use, and conspecific associations differed between eastern quoll (Dasyurus viverrinus) residents and reinforcers at a conservation-fenced haven. We used GPS collars to quantify distances travelled per night, home and core ranges, nocturnal (activity) and diurnal (denning) habitat use and preference, and conspecific associations over three periods: baseline (residents only, days 3–21), release (both cohorts, days 22–32), and settlement (reinforcers only, days 33–52) for ≤ 42 days post-release (depending on GPS unit longevity). Eastern quolls travelled greater mean distances per night (< 2.15 km, x̄ 1.75 km) and had larger home ranges (< 251 ha, x̄ 178 ha) during the release period. Reinforcers had larger home ranges (249 ha) and greater overlap with other collared eastern quolls (115 ha) when compared to residents (range 90 ha, overlap 46 ha). We found a significant preference for grassland habitat across all animals and periods. During the settlement period, we found a preference for nocturnal activity in greater understory and south-west facing aspects, and lower movement correlation, sociality, and den sharing between collared eastern quolls. Finally, we found lower den sharing in reinforcers (29%) compared to residents (52%), and for fawn- animals compared to dark-morphs. Our results revealed short-term movements, habitat use, and conspecific associations at a greater spatiotemporal resolution than has ever been achieved for this species. Our findings offer important insights into the importance of appropriate habitat and conspecific cueing for reintroductions, and highlight the need to monitor density-dependent mechanisms to inform adaptive management to promote positive outcomes for both initial reintroductions and reinforcements.

Out of shape: Ocean acidification simplifies coral reef architecture and reshuffles fish assemblages.

Climate change stressors are progressively simplifying biogenic habitats in the terrestrial and marine realms, and consequently altering the structure of associated species communities. Here, we used a volcanic CO2 seep in Papua New Guinea to test insitu if altered reef architecture due to ocean acidification reshuffles associated fish assemblages. We observed replacement of branching corals by massive corals at the seep, with simplified coral architectural complexity driving abundance declines between 60% and 86% for an assemblage of damselfishes associated with branching corals. An experimental test of habitat preference for a focal species indicated that acidification does not directly affect habitat selection behaviour, with changes in habitat structural complexity consequently appearing to be the stronger driver of assemblage reshuffling. Habitat health affected anti-predator behaviour, with P. moluccensis becoming less bold on dead branching corals relative to live branching corals, irrespective of ocean acidification. We conclude that coral reef fish assemblages are likely to be more sensitive to changes in habitat structure induced by increasing pCO2 than any direct effects on behaviour, indicating that changes in coral architecture and live cover may act as important mediators of reef fish community structures in a future ocean.

Step selection functions with non‐linear and random effects

Abstract Step selection functions (SSFs) are used to jointly describe animal movement patterns and habitat preferences. Recent work has extended this framework to model inter‐individual differences, account for unexplained structure in animals' space use and capture temporally varying patterns of movement and habitat selection. In this paper, we formulate SSFs with penalised smooths (similar to generalised additive models) to unify new and existing extensions, and conveniently implement the models in the popular, open‐source mgcv R package. We explore non‐linear patterns of movement and habitat selection, and use the equivalence between penalised smoothing splines and random effects to implement individual‐level and spatial random effects. This framework can also be used to fit varying‐coefficient models to account for temporally or spatially heterogeneous patterns of selection (e.g. resulting from behavioural variation), or any other non‐linear interactions between drivers of the animal's movement decisions. We provide the necessary technical details to understand several key special cases of smooths and their implementation in mgcv, showcase the ecological relevance using two illustrative examples and provide R code to facilitate the adoption of these methods. This paper offers a broad overview of how smooth effects can be applied to increase the flexibility and biological realism of SSFs.

Habitat features important for the conservation of the endangered Sloane’s Froglet (Crinia sloanei) in peri-urban environments

Context Determining and quantifying habitat selection of endangered species in peri-urban environments assists planners and managers to develop strategies and alternative conservation measures in the face of urban expansion and development. Sloane’s Froglet (Crinia sloanei), listed nationally as endangered in Australia, is a little-known species distributed within peri-urban environments, where foundational ecological information and the development of adequate conservation responses has been lacking. Aims (a) To determine a core calling period for Sloane’s Froglet and detection probabilities for occupancy surveys. (b) To understand and characterise the habitat that Sloane’s Froglet uses at the wetland and microhabitat scale. Methods We used generalised linear modelling and the information-theoretic approach to model habitat preferences for this species at two scales: the waterbody scale, and the microhabitat scale. We quantified the habitat characteristics of waterbodies occupied by Sloane’s Froglet in winter, its peak breeding period, by measuring the biophysical characteristics of 54 occupied and 40 unoccupied waterbodies. The microhabitat and relative spatial positioning of Sloane’s Froglet within waterbodies was examined at 54 calling sites in an area of one m squared around individual male Sloane’s Froglets and 57 randomly selected unused sites. Wetlands were surveyed multiple times to determine detection probabilities. Key results Model selection indicated that Sloane’s Froglet is 450 times more likely to occupy a waterbody when an adjacent ephemeral shallow overflow is present; and are more likely to be present when there is greater cover of small stem-diameter emergent vegetation and less bare ground on the bank. The microhabitat investigation of one m squared sites showed that Sloane’s Froglet’s calling sites are predominantly inundated, and at significantly shallower water depths, than unused sites. Sloane’s Froglet was found to always call from within the waterbody, distinguishing them from other sympatric Crinia species. Conclusions The habitat characteristics detailed provide information necessary for the management of Sloane’s Froglet and its habitat. Implications Housing and industrial development is occurring rapidly in Sloane’s Froglet habitat. The information provided here can be used to refine local and state government planning and better design appropriate responses. Indeed, results from this study are currently being used by agencies and environmental consultants when developing conservation plans and in the design of stormwater retention ponds in rapidly urbanising environments.

A risk-based approach to the analysis of potential climate change effects on fish communities associated to Posidonia oceanica in the Mediterranean

The Mediterranean is recognized as a climate change hotspot, with ongoing warming anticipated to impact its habitats and their associated fish fauna. Among these habitats, the seagrass Posidonia oceanica stands out as a foundational species, critical for the stability of coastal fish communities. However, our understanding of climate change consequences on P. oceanica associated fish fauna to date remains limited in part due to a lack of long-term data. This study aimed to highlight potential climate change risks to fish species associated with Posidonia, integrating data on species' thermal envelopes with their habitat and depth preferences into a climate change risk index. Specifically, 9 species, including three pipefish and several wrasse species of the genus Symphodus, emerged as being at higher potential risk from climatic change. A historical time series from Palma Bay (Balearic Islands, Spain), spanning 45 years and providing clear evidence of warming, was employed to evaluate trends in species abundance and occurrence in relation to their relative climate risk score. While certain high-risk species like Symphodus cinereus and Diplodus annularis showed an increase in abundance over time, others, such as the pipefish Syngnathus acus, Syngnathus typhle and Nerophis maculatus experienced declines. The absence of observed declines in some high-risk species could be attributed to several factors, such as acclimation, adaptation, or unmet response thresholds. However, this does not rule out the potential for future changes in these species. Factors such as increased nutrient influx due to growing human populations and changes in fishing regulations may also have contributed to the observed trends. These findings underscore the intricate interplay of environmental and anthropogenic factors and accentuate the pressing need for sustained, long-term data acquisition to fathom the implications of climate change on this highly important marine ecosystem.

Diversification of Camphorosmeae (Amaranthaceae s.l.) during the Miocene-Pliocene aridification of inland Australia

The Australian Camphorosmeae represent a monophyletic lineage that diversified to include ca. 150 spp. across 12 genera, and populate large parts of arid Australia. Tracking the origin and spread of this ancestrally salt and drought tolerant lineage provides additional evidence about the timing of the evolutionary history and phylogenetic assembly of arid habitats in Australia. Using a customized RADseq approach, sequence data for 104 species of the Australian Camphorosmeae representing all 12 genera were generated and included in phylogenetic and dating analyses. Furthermore, habitat type occurrences and preferences of species and clades were recorded. As suspected, the characters used to delimit current Australian Camphorosmeae genera do not support monophyletic groups, as phylogenetic analyses yielded 17 statistically supported clades across a large Maireana grade and crown radiation of Sclerolaena. The diversification of Australian Camphorosmeae is clearly linked to landscape changes and emerging new habitat types in arid Australia since the ancestral element likely arrived from temperate semi-arid to arid parts of continental Eurasia in the Middle Miocene. Migration was likely multidirectional and followed a west-to-east aridification. Crown group diversification was strongest during the Pliocene and likely promoted by the west-to-east expansion of Riverine Desert habitats and subsequent expansion and colonization of newly developing arid habitats. Rapid range expansion, fast habitat saturation, as well as periodic expansion, contraction and replacement of arid habitats, may have caused the rather species-poor clades of the earlier-divergent Maireana grade, compared to the continuously diversifying Sclerolaena clade.

Seasonal dynamics and habitat preferences of juvenile fish assemblages in the Wanquan Estuary, South China: Implications for conservation and management

Tropical estuaries encompass diverse habitats, which are crucial for supporting juvenile fish by providing nurseries, refuges, and migration routes. In the present study, we investigated the seasonal and spatial dynamics of juvenile fish assemblages in the Wanquan Estuary, Hainan Island, China, examining variations during the wet and dry seasons across four types of habitats. Our research aimed to test the hypotheses: (1) the wet season supports a greater abundance and species richness of juvenile fish compared to the dry season, and (2) juvenile fish showed varying habitat preferences across seasons. We recorded a total of 3617 individuals belonging to 33 families, 50 genera, and 78 taxa. Our findings revealed significant seasonal fluctuations in the assemblage structure, with peak abundance during the wet season in August, primarily consisting of diadromous species. A notable shift towards marine species was observed in March. Spatially, juvenile fish exhibited significant habitat preferences, with a strong preference for sand substrates for most species. Contrary to common expectations, mangrove fringe habitats were not identified as the primary nursery grounds for juvenile fish. Instead, our study highlights the importance of habitat diversity and connectivity in enhancing nursery functions. Water temperature and salinity were the key drivers influencing the seasonal and temporal patterns of juvenile fish assemblages in the Wanquan River estuary The pronounced temporal dynamics of these assemblages, driven by seasonal environmental alterations affecting water variations and habitat connectivity, were more significant than spatial differences. The findings emphasize the need for focused connectivity of various habitats to support the conservation of diverse fish communities in tropical estuarine ecosystems.

Implications of Ecological Drivers on Roan Antelope Populations in Mokala National Park, South Africa

Climate change has massive global impacts and affects a wide range of species. Threatened species such as the roan antelope (Hippotragus equinus) are particularly vulnerable to these changes because of their ecological requirements. Attempts to address concerns about the roan’s vulnerability have not been well documented in South African protected areas. This study identifies the landscape use and distribution of the roan as well as habitat and forage suitability changes to help inform management decisions for the conservation of roan. We used fine- and broad-scale data from Mokala National Park, South Africa that includes roan occurrence data, vegetation condition indices, vegetation (structure and plant species composition), elevation and temperature differences, and precipitation strata to construct a suitability framework using the Maximum Entropy (Maxent) and Random Forest statistical package. In Mokala National Park, roan occurred in the Schmidtia pappophoroides–Vachellia erioloba sparse woodland, Senegalia mellifera–Vachellia erioloba closed woodland, Senegalia mellifera–Vachellia tortilis open shrubland, Vachellia erioloba–V. tortilis closed woodland and Rhigozum obovatum–Senegalia mellifera open shrubland. The veld (vegetation) condition index (VCI) improved from 2019 (VCI &lt; 50%) to 2021 (VCI &gt; 60%), with the proportion of palatable grass species (Schmidtia pappophoroides and Eragrostis lehmanniana) also increasing. This study identified four key climatic conditions affecting roan distribution, namely annual mean daily temperature range, temperature seasonality, minimum temperatures of the coldest month, and precipitation of the wettest month. These results suggest that the conservation of roan antelope should consider these key variables that affect their survival in preferred habitats and foraging areas in anticipation of changing ecological conditions.

Spatiotemporal variation in size and abundance of juvenile Chinese mitten crab (Eriocheir sinensis) in Yangtze Estuary

IntroductionIntertidal habitat preferences and spatiotemporal variation in the abundance of juvenile Chinese mitten crab Eriocheir sinensis in Yangtze Estuary are reported.MethodsThe size and abundance of this crab are reported for mud flat, gravel, root belt, and marsh habitats in this estuary’s lower, middle, and upper reaches from June 2021 (spring) to February 2022 (winter) using quadrat method.ResultsJuvenile E. sinensis of carapace length (CL) 5.5 ± 2.1 mm (mean ± standard deviation) were collected; no juveniles were found in February 2022. Crab abundance in root belt and gravel habitats usually exceeded that of marsh habitat; no juveniles were found in mud flat habitat. The greatest abundances and smallest individuals were found when megalopa recruited in early spring (June); juvenile abundance decreased sharply afterwards, and crabs were absent from the intertidal during winter. Size and relative growth rate of juvenile crabs were greater in root belt and gravel habitat than in marsh habitat from June to August. Recruitment primarily drove changes in crab abundance and size during June and July, and temperature best correlated with changes in the winter. Many stage I juveniles (CL &amp;lt; 3.1 mm) occurred in the lower estuarine reaches, while stage III and IV juveniles (CL 3.9–6.5 mm) primarily occurred in the middle and upper estuarine reaches.DiscussionAlthough intertidal wetland habitat in Yangtze Estuary is severely degraded and reduced in area, it remains important for recruitment and maintenance of mitten crab populations. An understanding of the habitat requirements of this species will benefit management of this crab resource and the prioritized restoration of intertidal habitat.

Urban biodiversity conservation: A framework for ecological network construction and priority areas identification considering habit differences within species

The construction of ecological networks within the context of urbanization is an effective approach to cope with the challenges of urban biodiversity decline, representing a crucial goal in urban planning and development. However, existing studies often overlook the richness and uniqueness within species communities by homogenizing traits of species in the same class. This study proposes a framework for constructing and optimizing ecological networks focused on differential conservation within the same class. By classifying birds into three groups (specialists of water, forest or urban areas) based on their ecological requirements and urbanization tolerance, we constructed an ecological network tailored to their distinct migratory dispersal patterns. We then identified strategic areas including pinch points, barriers, and breakpoints specific to each bird group. Our findings reveal notable variations in suitable habitat distribution among different bird groups in urban environments. Corridor layouts varied according to habitat preferences and migratory dispersal patterns. Despite these differences, urban built-up areas persist as central hubs for the distribution of suitable habitats for 75% of bird species, with peripheral mountain-plain transition areas constituting 63% of crucial dispersal corridors. This emphasizes the critical role of urban built-up areas in maintaining biodiversity and ecological connectivity. Prioritizing connectivity between central urban areas and distant natural spaces is imperative. Our approach innovatively classifies and constructs networks to identify strategic areas with diverse species-specific attributes, providing valuable spatial information for land planning and guiding solutions to enhance target species. While the primary focus is on bird conservation in Beijing, our framework is broadly applicable to global biodiversity management and green planning under urbanization challenges. Overall, this study offers innovative insights for urban planning development and serves as decision support for prioritizing urban actions.

Modeling habitat suitability of wild rice (Zizania spp.) to inform restoration efforts in Michigan, U.S.A.

Wild rice (Zizania aquatica and Zizania palustris) has been an integral component of Michigan wetlands for thousands of years, but is disappearing today due to habitat loss. Identifying suitable habitats and associated environmental conditions for wild rice viability is a critical step toward guiding ongoing restoration efforts statewide. To this end, we used maximum entropy (Maxent), a presence‐only species distribution model, to characterize habitat preferences of wild rice in Michigan and identify suitable habitats for restoration. Extant wild rice occurrences were mapped alongside 11 environmental variables using Maxent to determine probabilities of occurrence throughout the state. The Maxent model (AUC &gt; 0.9) predicted the highest probabilities of wild rice occurrence in the western and southwestern regions of the state. Climatic variables, biotic interactions, and anthropogenic disturbances were all found to influence wild rice occurrence, with land cover, lower May precipitation, and minimum winter temperatures having the highest contributions to model predictions. The results of this study suggest that statewide restoration of wild rice in Michigan may be possible, although localized differences in environmental conditions should be accounted for when selecting restoration sites. With further refinement and the inclusion of more key environmental predictors of wild rice viability, habitat suitability models such as the one created in this study may be powerful and effective tools in guiding wild rice restoration efforts nationally.

Better to bluff than run: conservation implications of feral-cat prey selectivity

Context Predators typically select prey on the basis of their availability and traits such as body size, speed, camouflage and behaviour that influence ease of capture. Such selectivity, particularly by invasive predators, can disproportionately affect the conservation status of prey. Control of top-order predators can also trigger trophic cascades if subordinate predators have different prey preference. Aims We aimed to document prey selectivity of feral cats by comparing their diet with prey availability over a 27-year study in an Australian desert. Methods Stomach-content and demographic data were recorded from 2293 feral cats, showing 3939 vertebrate prey. These were compared with vertebrate-prey availability estimated from 224,472 pitfall-trap nights, 9791 Elliott-trap nights and opportunistic sampling that accumulated 9247 small mammal and 32,053 herptile records. Potential bird availability was assessed through 2072 quantitative counts amounting to 29,832 bird records. We compared cat selectivity among species, guilds, and physical and behavioural traits of potential prey. Key results Prey guild selectivity from two quantitative subsets of these data indicated that cats preferentially selected medium-sized rodents, snakes and ground-nesting birds over other prey guilds, and also preyed extensively on rabbits, for which selectivity could not be assessed. Species that froze or responded defensively to predators were less favoured than were prey that fled, including fast-evading species. Species inhabiting dunes were hunted more frequently relative to their abundance than were closely related species on stony plains. Conclusions The size, habitat preference and response to predators of potential prey species affect their targeting by feral cats. Implications Our results assist assessment of risk to wildlife species from cat predation and suggest that cat control will trigger changes in the relative abundance of prey species depending on their size, habitat use and behaviour.

Population Trends of the Ferruginous Hawk (Buteo regalis) Wintering in California

Abstract The Ferruginous Hawk (Buteo regalis) is a raptor of conservation concern in much of its range. Population trend estimates from Breeding Bird Surveys and migration counts for this species are often contradictory and of low credibility. Therefore, we used Christmas Bird Count data to assess population trends for Ferruginous Hawks that winter in California, USA. Evidence suggests that the birds breeding in southeastern Washington and northeastern Oregon may represent a metapopulation that winters almost exclusively in California. Data for the 25-yr period from Count Year 98 (winter 1997–1998) to Count Year 122 (winter 2021–2022) from 22 California Christmas Bird Count circles in the core winter range of Ferruginous Hawks showed a significant positive trend. This positive trend contrasts with the continent-wide negative trends observed for most grassland/open country bird species and is surprising given ongoing declines of this species’ preferred winter habitat in California during this same period. We discuss potential explanations that may account for these differences, including the possibility that the California-wintering Ferruginous Hawks include a large proportion of birds breeding outside of southeastern Washington and northeastern Oregon.

Home range, habitat use and capture-release of translocated leopards in Gir landscape, Gujarat, India.

Understanding the spatial ecology of translocated leopards (Panthera pardus fusca) is crucial for their conservation and the effective assessment of conflict management strategies. We investigated the home range and habitat preferences of five radio-collared leopards (n = 5; 2 males; 3 females) in the Gir landscape. Additionally, we examined the usefulness of the capture-release strategy for these animals. We assessed home range and habitat selection using kernel density estimation (at 95% and 50% levels) and compositional analysis. Our findings revealed that leopards exhibited distinct patterns of movement, often returning to their original capture site or nearby locations or exploring new areas within 3 to 25 days, covering distances ranging from 48 to 260 km. The average home range (95% FK) was estimated at 103.96±36.37 (SE) km2, with a core area usage (50% FK) of 21.38±5.95 km2. Seasonally, we observed the largest home ranges during summer and the smallest during winter. Males exhibited larger home ranges (95% FK, 151±64.28 km2) compared to females (56.18±14.22 km2). The habitat analysis indicated that agricultural areas were consistently preferred in the multi-use landscape at the 2nd order habitat selection level. Additionally, habitat around water bodies was highly favoured at the 3rd order, with distinct variations in habitat selection observed during day and night. This study highlights the significance of riverine and scrubland habitats, as leopards exhibited strong preferences for these habitats within their home ranges. We emphasize the importance of conserving natural habitat patches, particularly those surrounding water bodies. We also report on the characteristics of the capture-release strategy and provide our observations indicating no escalated aggression by leopards' post-release. In conclusion, this study evaluates widely employed approaches to conflict mitigation and suggests the continuous review and assessment of management strategies for mitigating human-leopard conflicts.

Seasonal mosquito (Diptera: Culicidae) dynamics and the influence of environmental variables in a land use gradient from Yucatan, Mexico

Mosquito-borne diseases constitute a significant global impact on public and animal health. Climatic variables are recognized as major drivers in the mosquitoes’ life history, principally rainfall and temperature, which directly influence mosquito abundance. Likewise, urbanization changes environmental conditions, and understanding how environmental variables and urbanization influence mosquito dynamics is crucial for the integrated management of mosquito-borne diseases, especially in the context of climate change. In this study, our aim was to observe the effect of temperature, rainfall, and the percentage of impervious surface on the abundance of mosquito species over a temporal scale of one complete year of fortnightly samplings, spanning from June 2021 to June 2022 in Yucatan, Mexico. We selected nine localities along an urbanization gradient (three natural, three rural, and three urban) from Mérida City to Reserva de la Biosfera Ría Celestún. Using BG-traps, mosquitoes were collected biweekly at each locality. Additionally, we estimated the percentage of impervious surface. Daily data of the maximum, mean and minimum temperatures, diurnal temperature range and rainfall were accumulated weekly. We calculated the accumulated quantities of temperatures and rainfall and lagged from one to four weeks before sampling for each locality. Generalized linear mixed models were then performed to study the influence of environmental variables and percentage of impervious surfaces on each of the 15 most abundant species. A total of 131,525 mosquitoes belonging to 11 genera and 49 species were sampled with BG-Sentinel traps baited with BG-lure and dry ice. The most frequently significative variable is the accumulated precipitation four weeks before the sampling. We observed a positive relationship between Cx. quinquefasciatus and Cx. thriambus with the diurnal temperature range. For Ae. aegypti, we observed a positive relationship with minimum temperature. Conversely, the percentage of impervious surface serves as a proxy of anthropogenic influence and helped us to distinguishing species exhibiting habitat preference for urban and rural environments, versus those preferring natural habitats. Our results characterize the species-specific effects of environmental variables (temperature, rainfall and impervious surface) on mosquito abundance.

Assessing the Home Range, Foraging Pattern and Roost Fidelity of Greater Short-nosed Fruit Bat (Cynopterus sphinx) in a Semi-Urban Environment

Radio telemetry is a method used in wildlife ecology to examine the movements and behaviours of animals, as well as to define their home ranges and habitat preferences. Bats, a highly diverse group of mammals, are recognized for their essential contributions to ecosystems, including seed dispersal, pollination, and pest control through their foraging activities. This study utilised radio telemetry to explore the basic foraging behaviours, range of movement, and roosting flexibility of the Cynopterus sphinx species. A total of 15 bats were equipped with compact, hand-wired, two-stage transmitter radio devices, including two harem males, nine harem females, and four non-harem males. Three groups used TRX-1000S receivers and collapsible 5-element Yagi antennas to track these radio-tagged bats. Our findings indicate that the radio-tagged female bats were the first to leave their roosts, with emergence times between 18:15 and 19:18 hrs. In contrast, harem males emerged last, following the quicker departure of non-harem males. The harem males covered an average foraging distance of 2.4 km (±0.3 km), whereas non-harem males travelled further. Both male and female bats visited multiple feeding sites nightly, with females travelling an average distance of 4.5 km (±0.9 km). Time spent at foraging sites varied among individuals. Males show higher roost fidelity than females, who frequently move between harems and roost sites. The study highlighted gender-specific differences in emergence times and distinct foraging behaviours, underlining the importance of understanding these patterns for conservation and habitat management efforts, which are crucial for supporting bats' roles as providers of ecosystem services.

An evaluation of small river restoration using transient river habitat modelling for macrozoobenthos

The mandate to maintain at least a good ecological status of all surface waters has led to increased river restoration projects across Europe in the past two decades. The aim is to re-establish the hydromorphological situation and reverse the damage to freshwater ecosystems. In this study, we evaluated the restoration measures in a small stream in the State of Saxony, Germany, using the Transient River Habitat Modelling for Macrozoobenthos (TRiMM). The model was established using the Physical habitat template, covering physical habitat variables (flow, substrate, and thermal regime). It also introduces the application of a fuzzy approach to investigate river physical conditions and their effects on biological indicators like macrozoobenthos. Three taxa, namely Ancyls fluviatilis, Ephemera danica, and Gammarus fossarum, with different habitat preferences, were used to investigate the river’s ecological conditions. The model simulated the natural flow conditions from spring to summer, before and after the restoration was implemented. The research indicated that the restoration of the studied river sections succeeded in providing suitable habitats for target taxa at varied discharge conditions.

Increased habitat availability as revealed by LiDAR contributes to the tropicalization of a subtropical butterfly community

AbstractSpecies redistribution through climate change remains a global problem. However, factors such as habitat availability can complicate the attribution of species distribution shifts. We used habitat metrics derived from repeated airborne LiDAR surveys in 2010 to 2020 to examine the underlying causes for the establishment of new butterfly species in Hong Kong. For six species newly arrived since 2000, we built species distribution models using the Random Forest algorithm based on LiDAR data from 2020 to characterize species' preferred habitats across the region. Through hindcasting, we applied the model to LiDAR data from 2010 to observe any changes in the availability of preferred habitat. We found widespread vertical forest growth across Hong Kong and increased probability of occurrence based on increased habitat availability for all six species. The underlying habitat drivers, however, varied significantly across species; two species (Lethe chandica, Notocrypta paralysos) were associated with closed forest while two other species (Prosotas dubiosa, Prosotas nora) were associated with urbanicity. Our results highlight how changes in habitat can occur concurrently with climatic change and together drive the redistribution of biodiversity. Particularly for vertically complex tropical forests, airborne LiDAR data can be leveraged to observe changes in habitat complexity and how these relate to shifts in species distributions.

Territory occupation sequence and population change 2005–2019 in a satellite versus core area for Grasshopper Warblers Locustella naevia

Because of habitat preferences and variation at a landscape level, a species’ distribution tends to show a level of aggregation. In the Grasshopper Warbler Locustella naevia, the distribution is linked to suitable breeding habitats of open grassy and herbaceous grounds, often adjacent to water. Consequently, the presence of the Grasshopper Warbler at landscape level will consist of core and satellite areas. In theory, birds can sense habitat quality and should occupy territories within those areas based on territory quality. It might also result in different population trends between different areas in the landscape. I tested these assumptions through a 15-year study in a satellite area, comparing the results to a nearby core area. In both areas, the males occupy a territory based on the perceived attractiveness, and general patterns of the territory utilization were similar between areas. Territory density was lower and the males arrived later in the satellite area, thereby confirming the satellite/core area relationship between the study areas. In the core area, no significant change in population size was noted, while in the satellite area, the population decreased significantly.