Preferred Microhabitat Research Articles

Habitat conservation enhances the resilience of the lizard Liolaemus cuyumhue to high summer temperatures

Habitat degradation from human activities affects essential microhabitats, threatening ecological processes like foraging, mating, locomotion, predator evasion, and competition among reptiles. We assessed how microhabitat selection and body temperature of the endangered lizard Liolaemus cuyumhue respond to differences in vegetation composition and thermal conditions between a disturbed site and an undisturbed site impacted by oil and gas activities in Argentina. During five expeditions between September 2022 and March 2023, we searched for L. cuyumhue and collected data on body temperature, substrate and air temperatures, body mass, snout-vent length, sex, and habitat characteristics. We also measured operative temperatures and assessed vegetation cover and microhabitat availability at each site. Our results showed significant differences in microhabitat characteristics and selection between sites. The undisturbed site had higher vegetation and lower operative temperatures, while the disturbed site had higher temperatures and lower vegetation, especially in summer. Lizards at the disturbed site showed higher body temperatures, suggesting stressful thermal conditions, and preferred microhabitats with lower bare ground cover. Capturing lizards in the disturbed site required more effort than in the undisturbed site. This study emphasizes the impact of habitat disturbance on the thermal environment and behavior of L. cuyumhue. Conservation efforts should prioritize maintaining and restoring vegetation to support the species’ thermoregulation needs, especially under global warming.

The Role of Local and Upstream Colonisation in Determining Stream Periphyton Metacommunity Assemblages.

Stream periphyton is an ideal study system for explaining how dispersal shapes community patterns. Few studies have tried to investigate periphyton metacommunities at the reach scale, and studies comparing local versus upstream periphyton propagule sources are lacking. We aimed to address these knowledge gaps by disentangling environmental constraints and dispersal sources, including dispersal hypotheses related to periphyton functional guilds. We covered 25-m sections of streambed with plastic silage cover sheets in three streams in Southern New Zealand, allowing river water to flow over the sheets. Samples on top of these sheets allowed periphyton colonisation only by drifting upstream propagules, while 'control' samples placed directly upstream of the plastic sheets were colonised by local and upstream propagules. We collected samples after 7, 14, and 25 days of colonisation. Response variables included periphyton biomass, community structure, and relative abundances of functional guilds. Control samples showed 1.5-6 times higher cell densities than plastic-cover samples, suggesting that local colonisation is very important for biomass accrual. Periphyton communities on both tile types became more similar to each other with time, indicating that environmental filters overcame effects of colonisation sources. While motile and flagellated taxa showed the ability to reach their preferred microhabitats in all streams, the responses of the remaining functional guilds did not follow the expected patterns. We conclude that periphyton community assembly strongly depends on reach-scale connectivity, which results in higher biomass accrual and community structure. These findings suggest that the mass effect paradigm is likely to be the principal metacommunity process shaping stream periphyton communities at the reach scale.

Guilty or innocent? Could the exotic lizard Hemidactylus mabouia (Squamata, Gekkonidae) be responsible for the displacement of the native species Notomabuya frenata (Squamata, Mabuyidae) in anthropic environments?

Hemidactylus mabouia is a gecko species that has successfully colonized southern North, Central, and South America. In Paraguay, there is a commonly held belief that this species has displaced the native skink Notomabuya frenata in urban areas. In this study, we compared several ecological features of N. frenata and H. mabouia to better understand the degree of their niche overlap. A comparative analysis was conducted based on a literature survey and the examination of museum specimens from Asunción (Paraguay). Furthermore, differences in microhabitat use between H. mabouia and N. frenata were investigated through a review of observational records available on iNaturalist. Our findings indicate that the two species share only a few biological traits, such as an insectivore diet, an ability to adapt to living close to human dwellings, and the use of mimesis as a primary defensive strategy. Both lizards are generalist feeders, although there are notable differences in their frequency of prey consumption. Regarding habitat use, the majority of N. frenata specimens were documented on grass or other natural substrates, as well as on trees and shrubs. In the case of H. mabouia, the majority of records originate from smooth and brick walls, including metal and glass surfaces. Consequently, there is no evidence to suggest that dietary overlap could induce competition between these species. Therefore, it can be posited that the displacement of the native lizard N. frenata is a consequence of human activities that have altered its preferred microhabitat while expanding potential habitat for H. mabouia.

Interspecific competition leads to more long‐winged morphs in two sympatric cricket species

Abstract Coexistence mechanisms for species competing for the same resource include resource partitioning, neutrality, microhabitat preference and trade‐off between competitive and dispersal abilities. We explored the coexistence mechanism of two species of trigonidiid crickets (Dianemobius nigrofasciatus (Orthoptera: Trigonidiidae) and Polionemobius taprobanensis (Orthoptera: Trigonidiidae)) that share the same habitat. Dianemobius nigrofasciatus is more common in areas where the ground surface is somewhat open, while P. taprobanensis is more common in more densely vegetated environments. The effects of micro‐environmental differences, similarities in competitive ability and investment in dispersal ability under interspecific competitive conditions on the coexistence of these species were examined using laboratory experiments. Both P. taprobanensis and D. nigrofasciatus performed better in vegetated environments. Although the adult emergence of D. nigrofasciatus were delayed by the presence of P. taprobanensis, the emergence rate of P. taprobanensis was not significantly affected by D. nigrofasciatus. The presence of P. taprobanensis caused a higher frequency of a long‐winged morph (macropterous) of D. nigrofasciatus. The results suggest that D. nigrofasciatus is inferior to P. taprobanensis in interspecific competition, and it, therefore, disperses (as macropterous adults) at greater rates in the presence of P. taprobanensis. Furthermore, it may be that D. nigrofasciatus has been forced to change its preferred microhabitat from vegetative habitats, which are inherently more suitable, to more open environments due to competition. These above mechanisms are thought to allow the two species to coexist in the same habitat.

Using mangrove and field observation data to identify fine-scale species distributions: a case study in bockadams (Serpentes: Homalopsidae: Cerberus).

Characterization of species distributions is a fundamental challenge in biodiversity science, with particular significance for downstream evolutionary studies, conservation efforts, field-based faunal studies and estimates of species diversity. Checklists and phylogenetic studies often focus on poorly known, rare taxa with limited ranges. However, studies of widely distributed, ecologically important species that are abundant in their preferred microhabitats are also important for systematics and local conservation efforts, but less often studied. We collected novel natural history data during fieldwork (2019-2023) for Philippine populations of bockadams (Homalopsidae: Cerberus), one of the most abundant vertebrates in Southeast Asian aquatic systems. Considered a coastal snake, many studies report Cerberus inland. We report the frequency of encounters of Cerberus schneiderii, and the IUCN data-deficient, Philippine-endemic Cerberus microlepis during six expeditions (62 days; 1041 person-hours). We report new occurrence data for 69 C. schneiderii and 6 C. microlepis for coastal and inland populations, water measurements and dietary observations. Regression analyses and ecological niche models show the importance of coastal and mangrove habitats for Cerberus. Our study is the most comprehensive assessment of Philippine Cerberus populations to date and provides critical baseline natural history data for downstream research on widespread and range-restricted species of Southeast Asian snakes.

Ant's Nest as a microenvironment: Distinct Mucoromycota (Fungi) community of the red wood ants' (Formica polyctena) mounds.

Many social insect species build nests, which differ from the surrounding environment and are often occupied by specific organismal communities. These organisms may interact mutualistically or parasitically with the nest-builders, or simply co-occur, being able to survive in these microenvironments. In temperate forests, red wood ants (e.g. Formica polyctena) are known to create distinct, highly developed nests, which consist of large, above-ground mounds, built primarily out of plant matter collected from the forest litter. The microorganismal communities of such mounds remain understudied. As representatives of Mucoromycota fungi commonly engage in the decomposition process of the forest litter, they would be expected to occur in the mounds. However, it is still not known whether the Mucoromycota community of these ants' nests differ from the one of the surrounding forest litter. In order to distinguish mound-associated taxa, we characterized Mucoromycota communities of Formica polyctena mounds and the surrounding forest litter. We sampled four sites, twice in a season. Sampled material was plated on agar media and emerging Mucoromycota colonies were identified based on their morphology. Fungal identification was further confirmed using DNA barcoding. In order to compare described communities, PERMANOVA test and non-metric multidimensional scaling ordinations were used. To distinguish taxa associated with the mounds, multilevel pattern analysis was performed. Our results show that the Mucoromycota community of Formica polyctena's mound differs from the community of the surrounding forest litter. While representatives of Entomortierella lignicola and Absidia cylindrospora clade were found to be associated with the mound environment, representatives of Umbelopsis curvata and Podila verticillata-humilis clade were associated with forest litter, and were rarely present in the mounds. Our findings strongly suggest that the red wood ants' nest is a specific microenvironment in the temperate forest floor, which is a preferred microhabitat for the mound-associated Mucoromycota, possibly adapted to live in proximity to ants.

Microclimate and Vegetation Structure Significantly Affect Butterfly Assemblages in a Tropical Dry Forest

Understanding the factors that influence the diversity and distribution of butterfly species is crucial for prioritizing conservation. The Eastern Ghats of India is an ideal site for such a study, where butterfly diversity studies have yet to receive much attention. This study emphasized the butterfly assemblages of three prominent habitats in the region: open forests, riparian forests, and dense forests. We hypothesized that riparian forests would be the most preferred habitat for the butterflies, as they provide suitable microclimatic conditions for butterflies. The study collected samples for 35 grids of 2 × 2 km2 for each habitat during the dry months (December–June). We considered the relative humidity, temperature, light intensity, elevation, and canopy cover to assess their influences on butterfly richness and abundance. We also considered the impact of disturbances on their distribution. We used structural equation modeling and canonical correspondence analysis to quantify the correlation and causation between the butterflies and their environment. The study recorded 1614 individual butterflies of 79 species from 57 genera and 6 families. During the study, we found that temperature was the most significant factor influencing butterfly richness. Relative humidity was also important and had a positive impact on butterfly richness. Riparian forests, where daytime temperatures are relatively low, were the most preferred microhabitat for butterflies. Open forests had greater species diversity, indicating the critical significance of an open canopy for butterflies. Though riparian forests need greater attention concerning butterfly distribution, maintaining open and dense forests are crucial for preserving butterfly diversity.

The scale-dependent role of submerged macrophytes as drift-feeding lotic fish habitat

Although submerged macrophyte (hereafter, “macrophyte”) communities are globally prevalent in low-gradient rivers, the net reach-scale effect of macrophytes on drift-feeding fish microhabitat preference is poorly understood. We used snorkeling and bioenergetics to study fish habitat selection for rainbow trout ( Oncorhynchus mykiss) in the Henrys Fork, ID, USA, investigating microhabitat preference across a reach-scale gradient of macrophyte growth. Fish preferred microhabitats with deep water, low velocity, and low macrophyte coverage. Preferences for microhabitats with higher net rate of energy intake (NREI) were modulated by reach-scale macrophyte coverage, higher coverage increasing preferences for higher NREI. Macrophyte coverage was a weak positive predictor for depth and NREI, and a weak negative predictor for water velocity and median substrate. Our results suggest trade-offs between fish predation risk and bioenergetic food intake, with macrophytes modulating these trade-offs across scales by affecting reach-scale geomorphology, bioenergetics, and predation risk. As such, this study highlights the important and dynamic role that macrophytes can play in fish population dynamics in rivers, with important implications for management decisions.

Morphological characteristics influence the spatial mixing patterns of shorebirds at Shengjin Lake.

The coexistence of species with similar ecological niches is one of the core interests of community ecology research. However, how functional feeding traits, including bill size and leg length, determine the niche of mixed flocks of shorebird species has seldomly been studied, as well as, microhabitat variables affect the spatial patterns of availability and the quality of patches for wintering. From October 2016 to March 2017 at Shengjin Lake, Anhui Province, China, we recorded 226 scan samples from the different microhabitats and 93 focal animal videos of four common shorebird species: common greenshank, spotted redshank, Kentish plover, and little ringed plover. We found that the species participating in the mixed groups were different in each microhabitat. The results of the overlap index for microhabitats and foraging techniques between the species were consistent with the morphological characteristics of these species. Kentish and little ringed plovers had the highest Pianka's niche overlap index values of 0.95 and 0.98 for microhabitats and foraging techniques, respectively, whereas common greenshank and spotted redshank had values of 0.78 and 0.89, respectively. Common greenshank and spotted redshank used four foraging techniques: a single probe (PR), multiple probes (MPR), a single peck (PE), and multiple pecks (MPE). Kentish and little ringed plovers only used PE and MPE. The mean bill size, mean leg length, and mean foraging frequency were significantly associated with water depth. The mean bill size and mean leg length were both significantly correlated with the mean foraging frequency of shorebirds. The vegetated area was the most important variable for grouping among shorebirds. We concluded that the four species showed differences in their preferred microhabitats and foraging patterns. Interspecific morphological differences, including bill and leg lengths, resulted in niche differentiation. Thus, effective resource allocation by regional species was realized, and a dynamic balance was achieved by the mixed foraging species. The information on foraging behavior and habitat requirements could be useful in the management of water levels in natural areas and conservation of a diversity of wintering shorebirds.

Socio‐ecological interactions promote outbreaks of a harmful invasive plant in an urban landscape

Abstract Urban landscapes often harbour organisms that harm people and threaten native biodiversity. These landscapes are characterized by differences in socioeconomic context, habitat suitability and patch connectedness. Identifying which spatial differences enable outbreaks of pests, pathogens and invasive species will improve targeted control efforts. We tested hypotheses to explain the distribution and demography of puncturevine Tribulus terrestris, a human‐dispersed invasive plant in Boise, a city in the western United States. We hypothesized an increase in puncturevine infestations near low‐valued properties with a high proportion of bare ground, the species' preferred microhabitat, that are well connected on the urban road network. To test these hypotheses, we collected data on the abundance, emergence and persistence of reproductive plants in transects spanning >100 km of our study city. We then used hierarchical Bayesian models to evaluate the impacts of spatial covariates on puncturevine distribution and demography. Bare ground cover consistently increased abundance, emergence and persistence of puncturevine, indicating the overarching importance of suitable establishment sites for this invasive species. Property value had the strongest impact on puncturevine abundance and was the most important main effect in the model for puncturevine emergence. In both models, lower‐valued properties had a higher risk of puncturevine occurrence. The effects of road network connectivity depended on bare ground cover, with the highest predicted abundance and emergence of puncturevine in patches with low connectivity on the road network and high bare ground cover. Understanding these relationships will require data that can disentangle seed dispersal from establishment limitations. Identifying characteristics of urban patches that promote outbreaks of harmful species will improve the effectiveness and equity of control efforts. The prevalence of puncturevine in lower‐valued properties is cause for concern as the plant impedes bicycle transportation, with the potential for disproportionate impacts on marginalized groups that lack resources to repair punctured tires. Our results add to a growing recognition that low‐connectivity street networks have undesirable outcomes for environmental sustainability. As urban land cover continues to grow worldwide, accounting for interactions between human, natural and built systems will play a crucial role in managing invasive species.

Selected microhabitat and surface temperatures of two sympatric lizard species

Many small lizards live in structurally and thermally heterogeneous environments where they can select preferred microhabitats and surface temperatures to optimize their activity. We examined microhabitat selection and analyzed surface temperatures selected by two ecologically similar lacertid species, Iberolacerta horvathi and Podarcis muralis, at three sites and in different ecological contexts: allotopic and syntopic conditions. We examined their microhabitat and spatial thermal selection by using high-precision geolocation techniques to locate the lizards and record surface temperatures with temperature data loggers. Microhabitat and thermal availability differed among sites: the I. horvathi allotopic site had more rock surfaces and was coldest; the P. muralis allotopic site had more ground surfaces and was warmer; and the syntopic site had the greatest surface and thermal heterogeneity. Our results highlight the differences in microhabitat selection between the two species, most notably in surface selection, but also in thermal characteristics. I. horvathi preferentially and almost exclusively selected rocks. P. muralis chose soil, but with a more general use of microhabitats. I. horvathi lizards chose colder temperatures than those available, while P. muralis chose higher temperatures than those available. Both species showed no differences in microhabitat selection between allotopic and syntopic sites, which could not be explained by differences between sites. Our results provided new insights into the difference in surface temperature selection between two lizard species that may be adapted to different environments.

Endangered plant species under differing anthropogenic interventions: how to preserve Pterygopleurum neurophyllum in Wondong wetland?

Endangered wetland plants are important as the potential keystone species and mediators for plant-soil interactions. Establishing conservation strategies for endangered plants is also prioritized because of the elevating extinction risk by human-induced wetland disturbances. The present study examined the factors controlling the incidence of Pterygopleurum neurophyllum, the endangered wetland plant experiencing severe habitat loss throughout Northeast Asia. Here, P. neurophyllum populations and their surrounding environments were addressed in the last natural Korean habitat to assess the possible influential factors (vegetation coverage, species richness, exotic plant species, coarse rock content, soil bulk density, and soil electroconductivity and pH) under anthropogenic wetland interventions (with or without soil disturbance). Our results showed that P. neurophyllum occurred 6 out of 32 plots in the study area. All P. neurophyllum were found in Miscanthus-dominated area, but preferred microhabitats featuring reduced vegetation coverage, increased species richness, and undisturbed soils under vegetation removal. Multimodel inference also indicated that vegetation coverage (relative importance = 1.00) and coarse rock content (relative importance = 0.70) were the major influential factors for P. neurophyllum population size, and the surviving P. neurophyllum were strictly limited to where both of them were kept lowered. Furthermore, the wetland intervention with soil disturbance had a negative effect on P. neurophyllum by creating the rocky and compacted soil surface as a result of land reclamation treatments. Conversely, the wetland intervention without soil disturbance enhanced the P. neurophyllum incidence by decreasing vegetation coverage of the overcrowding competitive plants. Overall findings reflect that the strategies to counteract habitat loss and manage the overly dense competitive plants should be necessary for conserving P. neurophyllum, as well as other wetland plants threatened by the human-induced disturbances and excessive competition intensities.

Functional Capabilities of Spiders in Support of Sustainable Agriculture

Modern agricultural techniques have a detrimental effect on ecosystems, and hence ecofriendly agriculture is required for sustainable agriculture with biodiversity conservation. Spiders play a vital role in keeping pest populations under control as an alternative to chemical pesticides. This study assessed the functional diversity of spiders to control pest populations by estimating their diversity in diurnal and seasonal appearance, preferred microhabitats, and hunting strategies. From August 2020 to November 2021, random quadrate sampling was undertaken in cultivated and wild plant communities. A metaanalysis of the ecology and diversity found that spiders have the capability to provide biological pest control against a wide variety of pests in Odisha’s coastal environment.

Microhabitat and patch selection detection from GPS tracking collars of semi-free ranging Mashona cattle within a semi-arid environment

Over the last 30 years, the global positioning system (GPS) tracking collars have significantly enhanced livestock grazing behavior studies. Practices designed to understand and improve livestock grazing distribution can now be accurately and cost-effectively monitored with GPS tracking. The behavior and spatiotemporal microhabitat selection of Mashona cattle relative to the season in a semi-free-range grazing system was evaluated using a low‐cost GPS herd activity monitoring (GPSHAM) collar. The GPSHAM automatically logged the position of the lead cow at 20-second intervals over a 7–hour daily grazing period. Additionally, the GPS data was complemented by visually observing the lead cow during daylight hours for nine successive days each in winter (July – August) and summer (February – March) of 2017. Summer and winter tracks were used to identify the Mashona cattle preferred grass species and hotspot areas by identifying the concentration of the GPS generated tracks and points (n ≥ 30) in each grid and were used to calculate the distance from the water source using the shortest distance to the water point from the hotspot patch (HSP). The activities of the lead cow were recorded at five-minute fixed intervals for every 60 minutes in the morning (09:00 – 10:00 hrs), afternoon (13:00 – 14:00 hrs), and evening (16:00 – 17:00 hrs). The percentage of the observation time spent on an activity for the observed animal was calculated for the duration of the observation. Results showed a significant difference in patch selection (p < 0.05) between summer and winter with 17 HSPs being identified in summer and 8 HSPs in winter. Again, the range of Mashona cattle movement was 0 – 3 km from the water source. Seasonal activity patterns varied significantly across seasons. Therefore, Mashona cattle foraging behavior depends on seasonal variation. The landscape and animal attributes responded to paddock nutritional level dynamics with more frequent use of patches with higher plant species diversity and near the water source. Our research is useful to range managers, researchers, and cattle ranchers as a guideline for forage management of cattle preferred microhabitats, pasture, and nutrition.

Fine-scale habitat associations of medusae and ctenophores along a gradient of river influence and dissolved oxygen

Environmental drivers of abundance and distribution are poorly described for many gelatinous zooplankton (GZ), yet this knowledge is essential to understanding the role of GZ in ecosystems and potential ecological impacts. In situ imaging systems are a contemporary approach to describe the relationship between GZ and their environment, providing detailed information on distribution and habitat preference. Here we quantify patterns in the abundance and distribution of medusae and ctenophores (>1 cm) related to oceanographic data collected with in situ imaging on the stratified northern Gulf of Mexico shelf. Fourteen taxa were identified, typically to genus level, including ctenophores, scyphomedusae, and hydromedusae. The site with the most freshwater influence and widespread bottom water hypoxia contained the highest taxonomic diversity of GZ, with Aequorea, Chrysaora, and Pelagia occurring only at this site. Although most taxa aggregated in particular oceanographic micro-habitats (e.g., surface, low salinity, high temperature, or deeper, high salinity, low temperature), some were habitat generalists, found evenly dispersed throughout the water column (e.g., Eutima) or bimodally distributed near the surface and bottom (e.g., Liriope). Paired day/night sampling revealed that most taxa did not vertically migrate, suggesting they remain in their preferred micro-habitats for extended periods of time and potentially serve as biological tracers of water masses. Imaging offers the ability to monitor these under-described size classes of GZ with higher taxonomic resolution and describe their fine-scale habitat preferences and vertical migration behaviors, which ultimately improves our understanding of how GZ disperse and interact with other zooplankton in stratified shelf waters.

The effect of microhabitat use on the foraging and diet of the striped bark scorpion, Centruroides vittatus (Buthidae: Scorpiones) in blackbrush habitat of south Texas

Microhabitat use by predators can be influenced by prey availability, predator size and risk of cannibalism. The preferred microhabitat for a predator can be for foraging, feeding or as a refuge. In this study in south Texas, Centruroides vittatus (Say, 1821) of all size classes utilized both ground and vegetation microhabitats. There was a high proportion of scorpions with caterpillars in legumes and low proportion of scorpions with any of the prey types on the ground. The median height of scorpions with prey did vary, with scorpions on legumes with caterpillar prey the highest and scorpions on other vegetation with dangerous prey the lowest. Intermediate size scorpions used legumes at a high frequency during January–April, and large scorpions used succulents at very high frequency during September–December. Scorpions climbed higher in blackbrush and other legumes than in other vegetation types. These results suggest that scorpions are actively foraging for caterpillars in legumes, and legumes are a quality microhabitat for foraging. The low proportion of scorpions with prey on the ground suggests that C. vittatus feed on prey on vegetation even if the prey was captured on the ground. A possible advantage for the scorpion to handle and consume prey on vegetation is lower predation risk or interference while feeding. The high use of succulents by the large scorpions cannot be explained by foraging success. A possibility is that succulents are preferred refuges by all C. vittatus but smaller scorpions avoid succulents because of the risk of cannibalism by the larger scorpions.

Intraspecific variation in microhabitat selection in reintroduced Chinese giant salamanders.

Reintroduction of captive-bred Chinese giant salamanders is a primary approach for restoring wild populations. Despite previous studies have investigated the habitat preferences of reintroduced Chinese giant salamanders, the intraspecific variation in their habitat selection has been neglected. In the present study, 30 captive-bred Chinese giant salamanders belonging to 3 groups (i.e., 10 males, 10 females, and 10 juveniles) were released into a montane stream to explore whether intraspecific variation in habitat selection occurred in this species using radiotelemetry. Our results indicated that linear home range and daily movement of males were significantly higher than those of females and juveniles. Male sedentariness was significantly lower than that of females and juveniles. No significant differences were detected between females and juveniles in these measures. Importantly, we found that males preferred microhabitats with low water conductivity and deep water depth. Females preferred microhabitats with high water conductivity, low dissolved oxygen and ammonium-nitrogen, and slow current velocity, while juveniles occupied microhabitats with low ammonium-nitrogen. In addition, males and juveniles exhibited higher niche breadth than females. Niche overlap was high between adults and juveniles but low between males and females. Our study revealed the presence of spatial segregation in reintroduced Chinese giant salamanders. Males, females, and juveniles exhibited variation in microhabitat selection. These results provide important information for use when planning strategies for conservation of Chinese giant salamanders.

Stygobiotic isopod Stenasellus sp. in Sarongge Jompong cave, Tasikmalaya karst area, Indonesia

Abstract. Kurniawan ID, Rahmadi C, Akbar RTM, Prakarsa TBP. 2022. Stygobiotic isopod Stenasellus sp. in Sarongge Jompong cave, Tasikmalaya karst area, Indonesia. Biodiversitas 23: 1495-1504. Stenasellus, a stygobiotic isopod, was first reported in Tasikmalaya karst by local cavers in 2018 in Sarongge Jompong Cave. This study aimed to investigate the population, activities, and habitat characteristics of Stenasellus sp. in Sarongge Jompong, Tasikmalaya karst area, Indonesia. Population and activities were recorded through direct intuitive search. We measured several important physicochemical parameters to study habitat characteristics. Statistical analyses-namely Non-metric Multi-dimensional Scaling and Detrended Correspondence Analysis-were conducted to understand the difference in water characteristics among microhabitats and the relation between water characteristics and population size. The results showed that the population was distributed in 4 microhabitats with the maximum observed individuals of 8. Several activities were successfully monitored, including crawling, resting, hiding in crevices, and moving to different locations through the water. All microhabitats were wet gours connected to small water currents located in the dark zone of the cave passage. Water characteristics of microhabitat site 1 were more similar to site 2 and the numbers of individuals in these sites were larger than sites 3 and 4. Among water parameters, resistivity showed the most robust relation with Stenasellus population in which both variables were positively correlated. This correlation indicated that Stenasellus sp. preferred microhabitats with less contamination. Intrinsic and extrinsic factors may potentially threaten the population. The potential threats and conservation challenges need to be identified and mitigated to reduce the risk of biodiversity loss to these isopods, mainly due to their small population size, specific microhabitat, and susceptibility to disturbance. Considering these factors, research on taxonomy will be essential for conservation efforts.

Drivers of fine-scale diurnal space use by a coral-reef mesopredatory fish.

The habitat preferences of many reef fishes are well established, but the use of space within these habitats by non-site-attached species is poorly studied. The authors examined the space use of a functionally important mesopredator, graysby (Cephalopholis cruentata), on six patch reefs in the Florida Keys. A 1m2 -scale grid was constructed on each reef and 16 individual C. cruentata were tracked diurnally in situ to identify space use. At the patch reef scale, larger C. cruentata were more active and had larger observed home ranges, although home ranges were also affected by fish density and the abundances of prey and predators. The total time in each 1 m2 grid cell was regressed against a range of fine-scale biotic variables, including multiple variables derived from structure-from-motion three-dimensional digital reconstructions of each reef. Nonetheless, time in grid cells (preferred microhabitats) was only significantly positively correlated with the height of carbonate structures, likely because the cavities they enclose are particularly suitable for predator avoidance, resting and ambushing prey. The ongoing flattening of reefs in the region caused by negative carbonate budgets is thus likely to have significant effects on the abundance and space use of C. cruentata. In addition to examining spatial patterns, we analysed C. cruentata waiting times in each grid cell before moving. These times were best approximated by a truncated power-law (heavy-tailed) distribution, indicating a "bursty" pattern of relatively long periods of inactivity interspersed with multiple periods of activity. Such a pattern has previously been identified in a range of temperate ambush predators, and the authors extend this move-wait behaviour, which may optimize foraging success, to a reef fish for the first time. Understanding how C. cruentata uses space and time is critical to fully identify their functional role and better predict the implications of fishing and loss of reef structure.

Responsive strategies of three sympatric small rodents to the altitudinal effects on microhabitats

Abstract This study evaluated the effects of altitudinal gradients on small-rodent populations and microhabitat conditions. We selected three altitudinal bands: lowland, mid-land, and highland. We captured three small-rodent species, the striped field mouse (Apodemus agrarius), the Korean field mouse (A. peninsulae), and the red-backed vole (Myodes regulus). A. agrarius preferred microhabitats with dense ground vegetation and sparse mid-story vegetation, basal area, downed trees, and stone coverage. A. peninsulae utilized ground vegetation, overstory vegetation, and downed trees. M. regulus occupied microhabitats with abundant stone coverage and little ground vegetation coverage. Ground vegetation coverage was higher in the mid-land. The lowland was characterized by high understory vegetation, bulky downed trees, and high stone coverage. A. agrarius mostly occupied the mid-land, whereas A. peninsulae and M. regulus mainly inhabited the lowland. Our results show that each small-rodent species had its own strategy for utilizing the key habitat factors in altitudinally affected microhabitats and for reducing competition among the populations. This finding contributes to improving knowledge of the ecological altitudinal features of microhabitat conditions, as well as the altitudinal distributions and abundances of three small-rodent species.