Specific Microhabitats Research Articles

Influence of microhabitat on the distribution of tadpoles of three endemic Nyctibatrachus species (Nyctibatrachidae) from the Western Ghats, India

AbstractAmphibians show a high amount of species richness and endemism. Such diversity can be attributed to their microenvironment as amphibians display fine‐scale heterogeneity depending on the microhabitats they inhabit. Tadpoles are considered as good indicators for understanding microhabitat–species association as they reflect the breeding sites and signify species survival potential. In this study, we assessed the microhabitat factors influencing the distribution of tadpoles of three endemic frogs of the genus Nyctibatrachus namely N. jog, N. kempholeyensis, and N. kumbara from central Western Ghats, India. Forty‐three streams were sampled from three river basins, and stream characteristics were analyzed using generalized linear models. The results indicate that the tadpoles show specific microhabitat preferences and spatial niche partitioning. Among microhabitat variables, the slope significantly influenced the distribution of tadpoles of N. jog and N. kempholeyensis. The tadpoles of N. jog preferred steep slopes, while N. kempholeyensis tadpoles were found in gradual slopes with low water depth. For N. kumbara tadpoles, water temperature significantly influenced their distribution in the streams. Such spatial heterogeneity promotes the coexistence of these species supporting the niche theory. The study advances the understanding of how amphibian diversity from the Western Ghats is shaped at the microhabitat scale. The perennial streams that the Nyctibatrachus tadpoles inhabit are at risk due to anthropogenic activities. The findings of this study provide important baseline data that could be useful for the conservation of the endemic anurans in the Western Ghats, India.

Mite communities (Acari: Mesostigmata, Oribatida) in the red belt conk, Fomitopsis pinicola (Polyporales), in Polish forests

The fruiting bodies of bracket fungi are a specific microhabitat colonized by various invertebrates of which mites (Acari) are rarely studied, and if they are, the study is usually faunistic. The aim of the research was to determine whether the diversification of mite assemblages (Mesostigmata, Oribatida) inhabiting the fruiting bodies of Fomitopsis pinicola (Sw.) P. Karst. (Polyporales) are connected with the character of the forests and/or the degree of decay (DD) of the fruiting bodies. The research was conducted at Białowieża National Park (BNP), in forests close to natural ones and in Karkonosze National Park (KNP) which was affected by a large-scale forest dieback in the 1980s. Eighty fruiting bodies (40 at each study site) of F. pinicola belonging to four DD categories were collected. In total, 4,345 individuals of 120 mite species were recorded at BNP, and 13,912 individuals of 96 species were recorded at KNP. Analyses revealed that the sample dispersion at each study site was comparable, nevertheless the samples from each study site were clearly grouped into slightly overlapping sets which allow observation of the differences between them. In the less decayed fungi (DD 1 and 2) there were fewer mite species and individual mites than in the more decayed samples (DD 3 and 4). There were also significant differences between the fauna of the fungi in each particular DD: the fauna of DD 1 differed from all others, whereas the fauna of heavily decayed fungi (DD 3 and 4) was more comparable.

Microhabitat characteristics related to seasonal roost switching: implications from a threatened and introduced cockatoo species in an urban landscape

BackgroundCommunal roosting is a common avian social behaviour, which potentially provides foraging benefits, predation avoidance or thermoregulation in birds. To identify the crucial environmental factors associated with roost site selection, most studies have focused on the comparison of physical characteristics between roosts and non-roosts. However, the differences among roosts have usually been neglected and the causes of roost switching have seldom been investigated.MethodsTo explore the variations among roost sites and assess the most influential environmental factors related to seasonal roost switching, we conducted a 105-day observation on an introduced population of critically endangered Yellow-crested Cockatoo (Cacatua sulphurea) in an urban environment in Hong Kong from 2014 to 2016. We identified seven roost sites that were occupied in different seasons and then measured their microhabitat characteristics in terms of land use types, human disturbance and microclimate temperature. To quantify these differences, we used Pearson’s chi-squared test, partial least squares determinant analysis (PLS-DA) and one-way repeated measures ANOVA, respectively.ResultsOur results distinguished roost sites occupied in three seasons, i.e. spring, summer and winter roosts, using several microhabitat characteristics. The land use types were significantly associated with roosts, where spring roosts were usually located in tree-dominated areas, which are the major feeding grounds. The discriminant analysis on human disturbance variables indicated that summer roosts were positively associated with night illumination. The microhabitat temperatures of winter roosts were significantly higher than those of most other roosts on cold nights.ConclusionsThe results highlighted significant variations among roosts, and seasonal roost switching was likely driven by specific microhabitat characteristics of each roost site, such as microclimate. It also helps us understand the behavioural adaptation of birds to urban environments.

Differences in ontogenetic and diurnal microhabitat selection by sympatric live‐bearing fish species with different reproductive modes

Abstract A pregnancy imposes a heavy reproductive burden on females. Some live‐bearing species have evolved reproductive adaptations to reduce this burden, which may influence their ability to use specific microhabitats. We investigate whether two such reproductive adaptations, placentation (embryo provisioning via a placenta) and superfetation (the ability to carry multiple broods at various developmental stages), influence microhabitat selection by five sympatric Costa Rican live‐bearing fish species (family Poeciliidae). Theory predicts that placentation and superfetation should both reduce the reproductive burden of females during pregnancy, improve their body streamlining, and swimming performance, and consequently allow them to use more performance‐demanding microhabitats. Here we apply underwater visual fish surveys to test a key prediction of this hypothesis, which is that the presence of these two reproductive adaptations is correlated with the use of microhabitats in the river that are characterised by a higher‐flow velocity. Consistent with our predictions, we observed significant interspecific differences in daytime microhabitat use: species that had both placentation and superfetation were found in deeper and faster‐flowing parts of the river, species that lacked both adaptations were confined to shallow slow‐flowing areas, and species with one adaptation (i.e. only superfetation) inhabited intermediate areas. This interspecific daytime microhabitat use was strongest in reproductive adults, intermediate in immatures, and absent in juveniles (the latter of which were all found in shallow low‐velocity zones), suggesting that ontogeny influences species‐specific microhabitat use. Finally, at night, all fishes, regardless of the species or age‐class, congregated in shallow slow‐flowing waters to rest (sleep) on the river bottom. Taken together, our results suggest that placentation and superfetation may be hitherto unrecognised reproductive features that help to explain differences in ontogenetic and diurnal microhabitat preferences between sympatric live‐bearing fish species living in environments characterised by large flow variation.

Diet and Feeding Strategies of the Crested Eagle (Morphnus guianensis) in the Brazilian Amazon

The Crested Eagle (Morphnus guianensis) is the second largest Brazilian forest eagle. Crested Eagles are distributed from southeastern Mexico to southern Brazil, northern Argentina, and Paraguay; however, the species is one of the least-studied Neotropical raptors. Our objective was to determine diet and feeding strategies for Crested Eagles in the Brazilian Amazon. We recorded Crested Eagle diet at four nests from 2010–2012 through a combination of direct observations from the ground, remote photographs (camera-traps), and pellets and prey remains collected in and under the nests. We identified a total of 79 prey individuals, composed of 21 different prey species. We found that Crested Eagles fed mainly on medium-sized rodents, and medium-sized to large mammals. Prey were mainly nocturnal (70%), including mostly scansorial, cavity-dwelling marsupials and rodents. Fewer prey were diurnal (20%) and these were typified by arboreal, gregarious mammals (monkeys); rare prey included one owl (Strigidae) and one porcupine (Coendou sp.). We suggest that this may indicate a diet not specialized on a particular prey species or group, but rather focused on specific prey behaviors or microhabitats.

Thermoregulatory strategies of three reclusive lizards (genus Xantusia) from the Baja California peninsula, Mexico, under current and future microenvironmental temperatures.

The thermal quality of the habitat is key for the regulation of body temperature in terrestrial ectotherms and, therefore, permits them to carry out their fundamental biological activities. In thermally heterogeneous environments, ectotherms might follow different behavioral or physiological strategies to maintain their body temperature within biologically adequate boundaries, for which they depend on microhabitat selection. These aspects are, thus, relevant in the context of habitat degradation and land-use change. In this study, we characterized the thermal ecology of three lizard species (genus Xantusia) that differ in microhabitat use along the Baja California peninsula, Mexico. We made three predictions: (1) the three species will follow different thermoregulatory strategies according to habitat thermal quality; (2) the thermal requirements and tolerances of these species will match the environmental or microenvironmental thermal conditions; and (3) due to their habitat and range restriction, the species studied will be highly vulnerable to climate change. Our results indicate the existence of thermoregulatory mechanisms in Xantusia to face thermal heterogeneity, including behavioral thermoregulation by choosing different microhabitats, shifts in activity periods, and adaptation to particular high thermal quality microhabitats. Furthermore, despite their association to specific microhabitats and specialized physiology, the studied species will not be adversely affected by climate change, as the increased microenvironmental temperatures will lead to a higher habitat thermal quality and lower costs of thermoregulation. However, we do not discard other indirect adverse effects of climate change not considered in this study.

Patterns of co‐occurrence and body size in dragonflies and damselflies (Insecta: Odonata) in preserved and altered Amazonian streams

AbstractInterspecific interactions, such as competition, are among the key factors that determine the distribution, abundance and diversity of organisms in natural communities of aquatic ecosystems. However, a marked reduction in the environmental integrity of streams may lead to modifications of the natural dynamics of these communities, including co‐occurrence patterns and body size. In the Amazon, the replacement of forests by production systems is one of the leading causes of alterations to riverine ecosystem. The insects of the order Odonata (dragonflies and damselflies) are predators known to compete for environmental resources but are also sensitive to environmental changes such as those caused by shifts in land use. In this scenario, the present study evaluated species co‐occurrence and body size patterns in adult odonates found at preserved and altered Amazonian streams, to determine whether there are morphological differences among the species that enable their coexistence. During the study, 98 streams in the eastern Amazon region were sampled, and a habitat integrity index (HII) was used to evaluate the integrity of each stream (based on variables such as the condition of the riparian vegetation and channel, and land use). Ten male individuals were selected from each species, and nine morphometric measurements were taken from each individual. A total of 3588 specimens were collected and distributed in nine families, 49 genera and 134 species. We found a non‐random pattern of co‐occurrence in the species of the odonate suborder Zygoptera and a random pattern in the suborder Anisoptera, in both preserved and altered streams. We found morphological divergence between pairs of zygopteran species, in the whole sample and both categories of stream integrity separately. No such morphological divergence was found in the pairs of anisopteran species. The distribution patterns of odonate species are limited by specific environmental processes, especially in preserved environments and in specialists, such as most zygopterans. Zygopteran species have more specific microhabitat requirements, which could explain this pattern, whereas anisopterans prefer open environments, which usually have a greater supply of resources, although there tends to be less microhabitat heterogeneity, which leads to reduced competition. Given this, future studies should use limiting similarity (e.g. morphological attributes) in addition to environmental and spatial factors to better understand the factors structuring these communities. Among these mechanisms, the effects of common ancestry (phylogenetic inertia) and biogeography are important factors that should also be considered in future studies.

Exploring the Thermal Microcosms at the Forest Floor—A Case Study of a Temperate Forest

With the expected changes in summer weather due to global warming, knowledge of the microclimatic variability at the forest floor dramatically increased in importance for silviculture, wildfire management and biodiversity issues. Thus, during the warm season in 2014, thermal aspects within a heterogeneous forest were recorded at nine sites and compared to data from a nearby weather station. It was found that soil (−5 cm) and near-surface (0–2 cm) temperatures under shaded conditions stayed remarkably cooler than temporarily or fully radiated spots inside and outside the forest; largest differences occurred in maxima (July: 22.5 °C to 53.5 °C). Solar radiation was found to be the main driver for the strong heating of near-surface microhabitats, which could be reinforced by the vegetation type (moss). The weather station widely reflected the average condition on forest floor, but lacks the biological meaningful temperature extremes. The measurement system (internal versus external sensor) resulted in differences of up to 6 K. The findings underline the importance of old or dense stands for maintaining cool microrefugia. However, also the need for careful selection and analysis of microclimatic measurements in forests, representative for specific microhabitats, under consideration of ground vegetation modifications.

Population status, threats, and conservation options of the orchid Dactylorhiza hatagirea in Indian Western Himalaya

Dactylorhiza hatagirea (D. Don) Soo (Orchidaceae) is a critically endangered high-value medicinal plant collected from wild and extensively used against diabetes, cuts/wound healing, gastric disorders, chronic fever, seminal weakness/dysfunctions, and bone fractures. The tuber of the species yields high quality “Salep” having astringent and aphrodisiac properties, with high economic value. This results in high demand and illegal collection of the species from wild, thus making this species one of the most exploited species in the Indian Himalaya. The populations of D. hatagirea are restricted to small isolated pockets and are subject to destructive harvesting, therefore, need urgent in situ as well as ex situ conservation interventions. In view of this, the present study is an attempt to understand population status, its distribution, threats, and vulnerability of the species. A total of 14 sites in different habitat types along the altitudinal gradient (2500–4500 m) were selected for intensive field study in the Indian Western Himalaya. The results of the study reveal that D. hatagirea prefers moist laden undulating habitats in alpine meadows. The population density of the species ranges between 0.70 and 2.43 individuals/m2 in alpine meadows of the studied sites. Population density and species abundance increased significantly along the altitude within its range of occurrence. The relationship between altitude and total density was curvilinear and significant (r2=0.666, p 0.247) between slope and total density. The results of the study also indicate that the vegetation in alpine ecosystem were more diverse in species composition at mid-altitudes (3400 to 3700 m) than high altitudes. Destructive harvesting of underground tuber and irregular grazing were observed as critical threats to the species. D. hatagirea share habitats with few expanding species (i.e., Polygonum polystachyum) and highly traded species (i.e., Ophiocordyceps sinensis) in the alpine meadows, which affects its population density. The study concluded that short life cycle, poor seed germination rate, specific microhabitat requirement, low population density, and high commercial value limit the widespread distribution of the species in the region. The findings of the study suggest an urgent need for developing conservation and management plan for the species in the region for sustaining traditional health care system and pharmaceutical demand.

Facilitation promotes plant invasions and indirect negative interactions

Numerous pressures influence the ecological capacity and health of drylands globally. Shrubs are often a critical component of these systems and can function positively as foundation species through facilitation of other species. Nonetheless, limited attention has been paid to the potential negative and indirect effects of shrubs. Here, we tested the hypothesis that plant facilitation can both accelerate the invasion process and amplify the negative effects of an invader on the native community. The invasive species Bromus madritensis ssp. rubens capitalized on facilitation by resident native shrub species. This in turn further degraded California mixed grasslands by negatively impacting other annual protégé plant species in these specific microhabitats. Indirect shrub‐mediated interactions were thus a critical component of the ecological community assembly processes, and this suggests that we need to move beyond pairwise interactions to more rapidly advance grassland management and restoration theory.

Nutrient loads and ratios both explain the coexistence of dominant tree species in a boreal forest in Xinjiang, Northwest China

The resource ratio hypothesis (RRH) and the nutrient-load hypothesis (NLH) state that species coexistence is mediated by the ratios and loads (availability), respectively, of multiple limiting resources. However, few attempts to quantify these effects in mature forest ecosystems have been attempted to date. Data were collected from 300 quadrats (20 m × 20 m) spread across a 12-ha (400 m × 300 m) boreal forest dynamics plot in the Kanas Reserve of Xinjiang, Northwest China. Torus translation tests were used to analyze associations between dominant tree species and specific microhabitats. Linear mixed models were used to assess how soil nutrient availability and nutrient ratios affected the abundance and basal area of specific tree species, as well as how these effects varied across life stages. Two shade-tolerant species, Picea obovata and Pinus sibirica, exhibited opposite relationships with soil nitrogen (N) and phosphorus (P) content. Picea obovata was associated with microhabitats with high N:P ratios, while P. sibirica preferred microhabitats with low N:P ratios. The light-demanding Betula pendula was most abundant at low N and P sites. Another light-demanding species, Larix sibirica, did not show any significant habitat preferences. Furthermore, N:P ratios mainly affected species abundance, while N and P contents largely impacted basal area. Soil nutrient effects on species distributions weakened with tree age (from saplings to adults). Different microhabitats in the boreal forest had distinct soil resources. Both nutrient ratios and loads were correlated with the distribution of dominant boreal tree species, though these effects weakened as trees grew, especially for shade-tolerant species. Overall, niche partitioning due to resource variation may alleviate interspecific competition and contribute to species coexistence, and this study provides convincing proof of the importance of both nutrient ratios and loads on maintaining boreal forest diversity.

Ecological scaling in mangroves: The role of microhabitats for the distribution of larval assemblages

Mangroves are regarded as important spawning and settlement grounds as well as nurseries for larvae and juvenile fishes and invertebrates due to the sheltered nature of these ecosystems. The present study examined the spatial and temporal distribution of fish and invertebrate larvae, simultaneously among several microhabitats, within two South African mangrove forests. Results indicate that despite temperature and salinity homogeneity across microhabitats, spatio-temporal differences occurred in both fish and invertebrate larval assemblages. The distinct larval assemblages were driven by the site-specific predisposition of taxa to occur more abundantly in one or more specific microhabitats, while temperature, salinity and tidal phase temporally structured both invertebrate and fish larval communities. The larvae of estuarine dependent marine fish occurred in mangrove microhabitats, suggesting they use structural mangrove patchiness as corridors or temporary nurseries before settling in situ, into their juvenile habitat. This study steers that the proposed nursery function or early stage role that mangroves play is driven by the structural uniqueness of mangrove microhabitats thus ensuring localised ecological linkages and functionality of these critical coastal environments.

The composition of endolithic communities in gypcrete is determined by the specific microhabitat architecture

Abstract. Endolithic microhabitats have been described as the last refuge for life in arid and hyper-arid deserts where life has to deal with harsh environmental conditions. A number of rock substrates from the hyper-arid Atacama Desert, colonized by endolithic microbial communities such as halite, gypsum crusts, gypcrete, calcite, granite and ignimbrite, have been characterized and compared using different approaches. In this work, three different endolithic microhabitats are described, each one with a particular origin and architecture, found within a lithic substrate known as gypcrete. Gypcrete, an evaporitic rock mainly composed of gypsum (CaSO4 ⋅ 2H2O) and collected in the Cordón de Lila area of the desert (Preandean Atacama Desert), was found to harbour cryptoendolithic (within pore spaces in the rock), chasmoendolithic (within cracks and fissures) and hypoendolithic (within microcave-like pores in the bottom layer of rock) microhabitats. A combination of microscopy investigation and high-throughput sequencing approaches were used to characterize the endolithic communities and their habitats at the microscale within the same piece of gypcrete. Microscopy techniques revealed differences in the architecture of the endolithic microhabitats and the distribution of the microorganisms within those microhabitats. Cyanobacteria and Proteobacteria were dominant in the endolithic communities, of which the hypoendolithic community was the least diverse and hosted unique taxa, as a result of less access to sun radiation. These results show, for the first time, that the differences in the architecture of a microhabitat, even within the same piece of a lithic substrate, play an essential role in shaping the diversity and composition of endolithic microbial communities.

Chemical cues may allow a fossorial amphisbaenian reptile to avoid extremely saline soils when selecting microhabitats

When selecting optimal habitats, animals should rely on detecting environmental cues that indicate the suitability of a given site. In fossorial animals, restrictions of the underground environment might limit the opportunities for habitat selection. However, field observations of some fossorial amphisbaenian reptiles indicate that microhabitat occupancy is not random. This might simply result from the low survival of individuals in suboptimal habitats, but it may reflect active behavioral selection. We suggest that, in the fossorial environment, chemical cues may be very important for actively selecting or avoiding specific microhabitats. Here, we tested the ability of Trogonophis wiegmanni amphisbaenians to discriminate and select different types of substrates by using chemical cues alone. In laboratory preference tests, amphisbaenians selected soils with low salinity levels (natural or experimentally manipulated), mimicking the microhabitat selection patterns observed in the wild. Moreover, chemosensory tests measuring tongue-flick rates showed that amphisbaenians discriminated using chemical cues alone between soil types according to natural salinity levels, and also between manipulated chemical stimuli with different salinity levels. These results suggest that the microgeographic patterns of distribution of these amphisbaenians are due to their ability to use substrate chemical cues to actively avoid extremely saline soils. and select optimal microhabitats.

A Century of Synergy in Termite Symbiosis Research: Linking the Past with New Genomic Insights.

Termites have long been studied for their symbiotic associations with gut microbes. In the late nineteenth century, this relationship was poorly understood and captured the interest of parasitologists such as Joseph Leidy; this research led to that of twentieth-century biologists and entomologists including Cleveland, Hungate, Trager, and Lüscher. Early insights came via microscopy, organismal, and defaunation studies, which led to descriptions of microbes present, descriptions of the roles of symbionts in lignocellulose digestion, and early insights into energy gas utilization by the host termite. Focus then progressed to culture-dependent microbiology and biochemical studies of host-symbiont complementarity, which revealed specific microhabitat requirements for symbionts and noncellulosic mechanisms of symbiosis (e.g., N2 fixation). Today, knowledge on termite symbiosis has accrued exponentially thanks to omic technologies that reveal symbiont identities, functions, and interdependence, as well as intricacies of host-symbiont complementarity. Moving forward, the merging of classical twentieth-century approaches with evolving omic tools should provide even deeper insights into host-symbiont interplay.

Niche differentiation, competition or habitat filtering? Mechanisms explaining co‐occurrence of plant species on wet meadows of high conservation value

AbstractQuestionsDue to the diverse abiotic conditions and the extensive, early‐autumn, manual mowing practiced once per few years, Molinia semi‐natural wet meadows are known for their high plant species diversity. However, recent socio‐economic transformations and land‐use changes (i.e. cessation of use) have been contributing to significant biodiversity loss in Molinia meadows. Thus, understanding the mechanisms of species co‐occurrence patterns operating on well‐developed Molinia meadows may be a precondition for the restoration or regeneration success of this type of vegetation. We aimed to identify community‐level co‐existence patterns of the whole set of plant species typical of Molinia meadows, and to assess the role of co‐occurring vegetation in shaping the performance of individual species.LocationNatura 2000 Special Area of Conservation “Łąki Dąbrowskie” (S Poland).MethodsUsing generalised multiple regression techniques on a set of vegetation traits and components of functional diversity, we assessed the role of different ecological mechanisms in shaping co‐occurrence patterns of the entire group of species typical of Molinia meadows, as well as individual species belonging to this group.ResultsWhen the entire group of Molinia meadow species was taken into account, niche differentiation emerged as the main mechanism influencing the co‐occurrence of plant species. When considering individual species, we revealed that their co‐existence patterns were mostly species‐specific, pointing out the predominant role of either niche differentiation, competition, habitat filtering, or a combination of these three drivers in shaping assembly processes.ConclusionsOur results showed that the variability of niches realised by target species typical of Molinia meadows was high. Therefore, conservation of well‐developed Molinia meadows should focus on both the community, and on a single species level, aiming to maintain a complex of specific microhabitat conditions. Considering small‐size patches of these meadows scattered in a transformed, agricultural landscape, conservation of individual target species should be of the highest priority.

Temporal variation in small nonvolant mammal (Cricetidae and Didelphidae) microhabitat associations in the Upper Paraná Atlantic Forest

Many questions concerning habitat preferences of Neotropical small mammals remain unanswered. These questions include where the animal lives within and among the available habitats, and the temporal (seasonal and interannual) variation in the habitat associations. The objectives of this research were: (1) to determine the associations of non-volant small mammal species (Rodentia and Didelphimorphia) with specific microhabitat characteristics including vegetation structure in an area near the western boundary of the Upper Paraná Atlantic Forest, and (2) to evaluate seasonal and interannual variation in those associations. Three grids were sampled in three seasons (Dry, Wet, Variable) during two years (2015-2017). The four predominant small mammal species (Gracilinanus agilis, Akodon montensis, Hylaeamys megacephalus, and Oligoryzomys nigripes) were evaluated for seasonal and interannual variation in habitat preferences. Each of the four exhibited seasonal and/or interannual variation in microhabitat preferences for three to six of the 17 environmental variables analyzed. This is the first study to explicitly evaluate temporal variation in habitat associations of small mammals in the Atlantic Forest ecoregion. The temporal patterns of habitat association among these four predominant species reveal a complex spatially and temporally dynamic composition and structure in this small mammal community.

Drainage basins serve as multiple glacial refugia for alpine habitats in the Sierra Nevada Mountains, California.

The evolutionary histories of alpine species are often directly associated with responses to glaciation. Deep divergence among populations and complex patterns of genetic variation have been inferred as consequences of persistence within glacier boundaries (i.e., on nunataks), while shallow divergence and limited genetic variation are assumed to result from expansion from large refugia at the edge of ice shields (i.e., massifs de refuge). However, for some species, dependence on specific microhabitats could profoundly influence their spatial and demographic response to glaciation, and such a simple dichotomy may obscure the localization of actual refugia. In this study, we use the Nebria ingens complex (Coleoptera: Carabidae), a water-affiliated ground beetle lineage, to test how drainage basins are linked to their observed population structure. By analysing mitochondrial COI gene sequences and genome-wide single nucleotide polymorphisms, we find that the major drainage systems of the Sierra Nevada Mountains in California best explain the population structure of the N. ingens complex. In addition, we find that an intermediate morphotype within the N. ingens complex is the product of historical hybridization of N. riversi and N. ingens in the San Joaquin basin during glaciation. This study highlights the importance of considering ecological preferences in how species respond to climate fluctuations and provides an explanation for discordances that are often observed in comparative phylogeographical studies.

Diversity and distribution of amphibians and reptiles in the Caramoan Island Group, Maqueda Channel, Southern Luzon, Philippines

We report for the first time the herpetological biodiversity (amphibians and reptiles) of the Caramoan Island Group (CIG), Maqueda Channel, southern Luzon Island, the Philippines. Herpetofaunal biodiversity assessment, using the standard field-based methodology for survey work, was conducted at nine sites in the CIG, off the northeast coast of the Bicol Peninsula of southern Luzon. The overall species richness (s) in the CIG is 22 (three amphibians, 12 lizards, and seven snakes) represent new island records for a variety of the native species, ten of which are endemic to the Philippines. Beta diversity (β-diversity) of the CIG is 0.84 reflecting a relatively high degree of local area turnover of species when among-site comparisons were quantified; this finding most likely reflects habitat variability which is consistent with our observation emphasizing how a high proportion of faunal diversity is associated with, or confined, to very specific microhabitats (limestone areas, lower-montane forests, mangroves, beach coastal forests, etc.). The overall community similarity index of the archipelago was 0.545 implying that CIG has moderate overlap of amphibian and reptilian species composition. Our findings provide baseline information on the unique composition of herpetofauna in the CIG, which highlights a general paucity of knowledge about the Peninsula’s herpetofaunal diversity.

The Rhizosphere Talk Show: The Rhizobia on Stage

From bacterial quorum sensing to the signals of bees, communication is the basis of biotic interactions. Frequently, more than two organisms can take part in the speeches, resulting in a complex network of cross-talks. Recent advances in plant-microbe interactions research have shown that communication, both inter-kingdom and intra-kingdom, is shaped by a broad spectrum of factors. In this context, the rhizosphere (i.e., the soil close to the root surface) provides a specific microhabitat where complex interactions occur. The complex environment that makes up the rhizosphere can select for certain microbial populations, which are adapted to this unique niche. Among them, rhizobia have emerged as an important component of the rhizospheric microbiome. The aim of this review is to explore the components of such a rhizospheric Talk Show in the frame of the rhizobium-legume interactions. This symbiosis is a complex process that involves several signals that can be shaped by plant rhizospheric exudates and microbiome composition. The relationship established by rhizobia with other rhizospheric organisms, together with the influence of the environmental factors, results in their beneficial role on host plant health. Here, we resume research accounting strategies, molecules, and organisms that influence the place of rhizobia in the rhizosphere. The focus is on the most recent approaches for the study and subsequent exploitation of the diversity of the organisms. Indeed, the study of plant-microbes communication and evolution is fundamental to develop highly efficient inoculants able to reduce the use of fertilizers in agriculture.