Microhabitat Types Research Articles

Temporal variations of spontaneous plants colonizing in different type of planted vegetation-a case of Beijing Olympic Forest Park

The planted vegetation in urban green spaces generally not only needs intensive maintaining practices but also has resulted in landscape homogeneity and biodiversity decrease. With the increasing ecological awareness, spontaneous plants which were seen as ‘weeds’ have gained attention for their variety of positive attributes. To provide an insight for designers to cooperate with them, we took Beijing Olympic Forest Park as the study area, and explored the temporal patterns of spontaneous plants in relation with planted vegetation. A total of 614 plots were selected from 123 sample sites using a 200-m grid placed over the park. Each plot was a 1 m × 1 m square, and was assigned one microhabitat type according to the type of planted vegetation. All plots were surveyed seven times during the growing season from March to November, 2015. A total of 128 spontaneous species were recorded, which belonged to 98 genera and 32 families. It was under-tree and unplanted plots contained the most species among all of the other microhabitats whereas lawn presented the lowest species number throughout the growing season. Significant differences were found among the microhabitats with respect to species richness and community diversity of spontaneous vegetation, with under-tree and lawn were dramatically lower compared to unplanted plots during the whole summer. In contrast, the most diverse communities were recorded at waterside unplanted plots. Moreover, community diversity and species niche width among different microhabitats were not stable because of the varying degrees of external interference in different seasons. Totally 21 distinct colours of spontaneous vegetation were identified during the survey season. Each season and microhabitat had its own dominant species and assemblages. The results of this research can provide a reference for the future design of sustainable and resilient urban vegetation that is both ecologically productive and aesthetically pleasing, and at last has substantial potential for a greater inherent stability in the face of global climate change.

Microhabitats can be recruitment refuges and sinks

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 626:15-27 (2019) - DOI: https://doi.org/10.3354/meps13070 Microhabitats can be recruitment refuges and sinks Paul E. Carnell1,2,*, Michael A. Sams3, Michael J. Keough1 1School of BioSciences, The University of Melbourne, VIC 3010, Australia 2Deakin University, Geelong, Australia. School of Life and Environmental Sciences, Centre for Integrative Ecology, (Burwood Campus), 221 Burwood Highway, Burwood, VIC 3125, Australia 3Environment Protection Authority, Ernest Jones Drive, Macleod, VIC 3085, Australia *Corresponding author: paul.carnell@deakin.edu.au ABSTRACT: Recruitment is an important demographic bottleneck in the life history of many plant and animal species. Microhabitats provided by surfaces or plants or animals can reduce mortality during this critical life-history period. We investigated how microhabitats influence post-settlement processes on a range of ascidians, bryozoans and barnacles. We compared post-settlement mortality and growth on surfaces that were flat or were covered by artificial barnacle mimics or live adult barnacle microhabitats. We also tested whether the effects of surface type changed under different levels of environmental stress by manipulating the orientation of treatments. Orientation had the strongest influence on survival, growth and recruitment, with individuals on downwards-facing surfaces performing the best and those on upwards-facing surfaces with significantly higher mortality. The bryozoan Watersipora subatra had higher survival in microhabitats, but was not influenced by surface orientation. In contrast, barnacles showed increased mortality in microhabitats on upwards-facing panels, but were not affected by other orientations. The presence of adult barnacles caused decreased growth of barnacle recruits, but had no effect on the bryozoan. In comparison, the ascidians (Botryllus sclosseri and Diplosoma listerianum) were mostly not influenced by microhabitats. The high rates of sedimentation on upwards-facing surfaces provide the most plausible answer for the strong influences of surface orientation on survival and growth. While microhabitats can act as refuges for some species, the same microhabitat type can lead to higher mortality in other species. The response of each species to microhabitats ultimately depends on the source of mortality at each site. KEY WORDS: Post-settlement mortality · Habitat characteristics · Settlement · Environmental variability · Ascidian · Bryozoan · Barnacle Full text in pdf format PreviousNextCite this article as: Carnell PE, Sams MA, Keough MJ (2019) Microhabitats can be recruitment refuges and sinks. Mar Ecol Prog Ser 626:15-27. https://doi.org/10.3354/meps13070 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 626. Online publication date: September 12, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Modeling operative temperature in desert tortoises and other reptiles: Effects imposed by habitats that filter incident radiation.

We challenged the common practice of using a single mean absorptance based on unfiltered skylight spectra to model operative temperature for reptiles in filtered light habitats by examining the effects of plant canopies on light transmittance. To assess differences in light filtration over a range of microhabitats, spectra were recorded under canopies of desert plants, tropical plants, and under unfiltered skylight. Spectra were then integrated with absorptivity curves of desert reptiles to determine if differences in light quality among microhabitat types changed integrated mean absorptance. Finally, we used the desert tortoise (Gopherus agassizii) as a case study to investigate the effects of filtered microhabitats on paint choice for physical operative temperature models and determined the magnitude of error that could result from discrepancies between paint and animal absorptance. We found that light energy was partitioned similarly among microhabitats with like canopy types and that most variation was explained by differences in transmittance between the visible and near infrared wavelengths. Mean absorptance for reptiles was similar among microhabitats with the greatest differences observed between animals in unfiltered skylight and under tropical canopies. In most microhabitats paint and tortoise absorptances differed, but operative temperatures were nearly identical within microhabitats no matter the absorptance used in the model. The findings of this study support the use of a single mean absorptance in modeling operative temperature for reptiles in a variety of habitats.

Risk of predation: a critical force driving habitat quality perception and foraging behavior of granivorous birds in a Nigerian forest reserve

BackgroundUnderstanding the factors that influence the foraging behavior and perception of habitat quality by animals has long been the focus in ecology. Due to the direct effect resource acquisition has on an individual’s fitness and species’ survival, predation risk is considered widely to be a major driver of foraging decision. The objectives of this study were to investigate how predation risk is perceived by granivorous bird species with respect to different habitat and microhabitat types, time of day and food types in Amurum Forest Reserve, Nigeria, with a view to direct future conservation planning.MethodsFor 3 months, we conducted field experiments to measure giving-up densities (GUD, the amount of food left behind in artificial patches after birds cease to forage in it) and how it differs with habitat types, microhabitats, times of day, and food types. General linear mixed-effect models (GLMMs) were fitted to investigate the differences in GUD with respect to the aforementioned variables. Model selection was done based on the Akaike’s Information Criterion (AIC).ResultsThere was no significant difference in GUDs across habitats. However, there was a significant difference in GUDs between microhabitats. Higher food remnants were recorded in the open than in cover microhabitats, as birds exploited food patches in the cover more. Time of day influenced foraging behavior in the birds. They foraged more in the morning than afternoon across all three habitats except for the gallery forest where birds foraged less in the morning. Higher GUDs were recorded in open than cover microhabitats both in the morning and the afternoon. Birds had a preference for rice, millet, and groundnut respectively.ConclusionThe differences in GUDs were very indicative of differences in foraging behavior and perception of resource availability in response to perceived predation risk. Therefore, this study suggests that the understanding of foraging decisions can be a veritable method for assessing habitat quality as perceived by animals.

Advances in the studies of plant diversity and ecological adaptation in the subnival ecosystem of the Qinghai-Tibet Plateau

<p indent=0mm>The alpine subnival belt, located at the front of the alpine life zone, very close to the snowline at high elevations, is the highest habitat of all terrestrial ecosystems. Due to various harsh environmental factors, the alpine subnival belt offers the most hostile conditions for the survival, growth and development of plant species. However, due to its highly varied climates, extremely diverse types of microhabitats, and unique corridor or isolation barrier for plant species, the Qinghai-Tibet Plateau (QTP) hosts the richest alpine subnival plant biodiversity in the world; and the driver for speciation, as well as the mechanisms of sustaining plant diversity in the alpine subnival ecosystem in this region are areas of interest for many researchers. Many recent studies have revealed: Highly specialized morphological features, such as large semi-translucent bracts, dense hairy inflorescences, and nodding flowers that appear in various systematically distant plant species, have multifold functions to protect their vegetative and reproductive organs from high intensity UV radiation, low temperatures, and high humidity, therefore improving the survival rate of these plant species in such a hostile environment. Numerous other researches have reported how advantageous reproductive strategies that have evolved in subnival plant species of the QTP, including the hermaphroditism system, dry fruits, delayed germination behavior and persistent seed bank, promote the probability of reproductive success. In addition, some studies have highlighted the critical role of plant-plant interactions, in particular the facilitation of other plant species by keystone species (e.g. <italic>Arenaria polytrichoides</italic>, <italic>Potentilla articulata </italic>with cushion morphology), and unique plant-pollinator interactions between flagship species (e.g. <italic>Rheum nobile</italic> with large semi-translucent bracts covering inflorescence) and insects on the composition and sustainability of plant diversity in the subnival ecosystem of the QTP. On the other hand, as a region extremely sensitive to climate changes, the subnival habitat has experienced great changes in appearance over the past decades. Recent reports have stated that as a result of warmer climates, the expansion of areas for plant migration and colonization has brought increasing species richness in some subnival areas of the QTP (e.g. the Hengduan Mountains, SE QTP). Yet at the same time, by taking advantage of the continuous rise in temperature, many lowland and middle-elevation plant species will be able to invade this cold-edge ecosystem, causing in a great compression in the niche of some typical and/or endemic subnival plant species and finally resulting in a dramatic decrease in the diversity and functions of the subnival ecosystem. Undoubtedly, the findings obtained from numerous studies on all aspects of terrestrial evolution in recent decades have improved our understanding of ecological adaptation and sustainability of plant diversity in the subnival ecosystem of the QTP. In the future, we still need to focus on: (1) Unveiling the adaptive mechanisms of the striking morphological characteristics of subnival plant species from a molecular and/or genome level; (2) exploring how the buffer effects of the safety net produced by keystone species (e.g. cushion plant) influence global warming on the plant diversity of subnival ecosystem; (3) examining the beneficiary feedback effect on benefactor species and changes in the plant-pollinator co-evolutionary interaction, under global warming and human activity disturbance; (4) investigating how species richness, phenological pattern, and the functional traits of subnival plant species respond to global warming; and (5) testing the importance of plant diversity on the functions and evolution of the subnival ecosystem, and the potential influence of plant diversity loss on the stability and integrity of the subnival ecosystem, through field experiments in permanent plots and historical records of plant collections and vegetation surveys.

Secondary succession has surprisingly low impact on arboreal ant communities in tropical montane rainforest

AbstractUnderstanding forest regeneration processes is increasingly important as disturbed forests spread rapidly in tropical landscapes. While successional dynamics are relatively well‐understood for plants, they remain poorly known for tropical insects, particularly in montane rainforests and tree canopies. We studied the effect of montane forest succession on arboreal ant communities in New Guinea near their natural elevational limit (1800 m a.s.l.). We censused ant species and nests in replicated 0.1‐ha plots of primary, old and young secondary forests, destined to be felled for gardens by the local landowners. Overall, 1249 felled trees were dissected for all ant‐associated microhabitats. We used rarefaction‐based models manipulating vegetation structure and multivariate randomizations to assess the effects of tree density, tree size, and nesting microhabitats on the ant communities. We expected increased ant species diversity, microhabitat specialization, and species turnover among trees throughout the succession, with distinct community composition among the stages. In contrast to our expectations, ant species composition and diversity per plot did not change during succession, and species similarity among trees was significantly higher only in old secondary forest. The number of ant species per tree increased with forest age, but trees of similar size hosted only slightly more species in primary than secondary forests. Many ant species were associated with particular nesting microhabitats; however, the same microhabitat types occurred in all stages and thus did not generate successional trends in ant communities. Secondary succession had an unexpectedly low impact on tree‐dwelling ant communities in this montane ecosystem, in contrast with our previous findings from lowland rainforests. These results highlight the need to study successional processes along entire elevational gradients, as montane taxa may react differently to vegetation changes than their lowland counterparts.

Microhabitat Heterogeneity and Population Ecology of Ribbed Mussels (Geukensia demissa) Near Their Northern Range Limit (Maritime Canada)

Population dynamics of sessile marine invertebrates are potentially affected by variation in abiotic variables among microhabitats. The ribbed mussel (Geukensia demissa), an ecosystem engineer in salt marshes from Cape Cod to northern Florida, inhabits two microhabitats in salt marshes near its northern range limit, Maritime Canada: the exposed seaward edge of the marsh (edge) and the edge of creeks (creek). To determine differences in population dynamics of ribbed mussels between these microhabitats, population, demographic, and abiotic variables were measured at multiple sites over 1 to 2 years. Water flow was higher, temperature less variable, and winter shoreline disturbance less prevalent along creeks than edges. Mussels showed some minor demographic differences between microhabitats: a slightly delayed onset of gametogenesis, and a tendency to lower female reproductive output and more settlers (although overall numbers were low) within creeks. These differences did not translate into consistent differences in population variables across microhabitat types, namely density, size structure, and individual growth of juveniles and adults. Although creeks appear to be more suitable habitat based on abiotic variables measured, mussel population variables may be limited by a combination of temperature and food availability or quality, or some other factor. Overall, population dynamics of ribbed mussels are similar between creek and edge microhabitats in salt marshes in Maritime Canada. This study contributes a first assessment of the dynamics of a potentially key salt marsh species near its northern range limit.

Are all patches worth exploring? Foraging desert birds do not rely on environmental indicators of seed abundance at small scales

BackgroundConsumers should show strong spatial preferences when foraging in environments where food availability is highly heterogeneous and predictable. Postdispersal granivores face this scenario in most arid areas, where soil seed bank abundance and composition associates persistently with vegetation structure at small scales (decimetres to metres). Those environmental features should be exploited as useful pre-harvest information, at least to avoid patches predicted to be poor. However, we did not find the expected spatial association in the algarrobal of the central Monte desert by observing foraging seed-eating birds, a field technique influenced by how much they exploit visited patches. In this work we tested if the first stage of foraging by granivorous birds (patch visit, encounter or exploration) is positively associated with environmental indicators of patch quality by recording the removal of single seeds from 300 scattered experimental devices during seasonal trials. Spatial selectivity was analysed by comparing the structural characteristics of used vs. available microhabitats, and evaluated against bottom-up and top-down hypotheses based on our previous knowledge on local seed bank abundance, composition and dynamics. Their foraging activity was also explored for spatial autocorrelation and environmental correlates at bigger scales.ResultsPostdispersal granivorous birds were less selective in their use of foraging space than expected if microhabitat appearance were providing them relevant information to guide their search for profitable foraging patches. No microhabitat type, as defined by their vegetation structure and soil cover, remained safe from bird exploration. Analyses at bigger temporal and spatial scales proved more important to describe heterogeneity in seed removal.ConclusionsCloseness to tall trees, probably related to bird territoriality and reproduction or to their perception of predation risk, seemed to determine a first level of habitat selection, constraining explorable space. Then, microhabitat openness (rather than seed abundance) exerted some positive influence on which patches were more frequently visited among those accessible. Selective patterns by birds at small scales were closer to our predictions of a top-down spatial effect, with seed consumption creating or strengthening (and not responding to) the spatial pattern and dynamics of the seed bank.

Effects of maternal source and progeny microhabitat on natural selection and population dynamics in Alliaria petiolata

The success or failure of propagules in contrasting microhabitats may play a role in biological invasion. We tested for variation in demographic performance and phenotypic trait expression during invasion by Alliaria petiolata in different microhabitats. We performed a reciprocal transplant experiment with Alliaria petiolata from edge, intermediate, and forest understory microhabitats to determine the roles of the environment and maternal source on traits, fecundity, population growth rates (λ), and selection. Observations of in situ populations show that edge populations had the highest density and reproductive output, and forest populations had the lowest. In experimental populations, population growth rates and reproductive output were highest in the edge, and the intermediate habitat had the lowest germination and juvenile survival. Traits exhibited phenotypic plasticity in response to microhabitat, but that plasticity was not adaptive. There were few effects of maternal source location on fitness components or traits. Alliaria petiolata appears to be viable, or nearly so, in all three microhabitat types, with edge populations likely providing seed to the other microhabitats. The intermediate microhabitat may filter propagules at the seed stage, but discrepancies between in situ observations and experimental transplants preclude clear conclusions about the role of each microhabitat in niche expansion. However, edge microhabitats show the highest seed output in both analyses, suggesting that managing edge habitats might reduce spread to the forest understory.

Contrasting Water Quality Treatments Result in Structural and Functional Changes to Wetland Plant-Associated Microbial Communities in Lab-Scale Mesocosms.

The impact of contrasting water quality treatments on wetland plant-associated microbial communities was investigated in this study using 12 lab-scale wetland mesocosms (subsurface flow design) planted with reed canary grass (Phalaris arundinacea) or water speedwell (Veronica anagallis-aquatica) over a 13-week period. Mesocosms received water collected from two sites along the Grand River (Ontario, Canada) designated as having either high or poor water quality according to Grand River Conservation Authority classifications. All mesocosms were established using sediment collected from the high water quality site and received water from this source pre-treatment. Resulting changes to microbial community structure were assessed using PCR-denaturing gel gradient electrophoresis (DGGE) on microbial 16S rDNA sequences extracted from rhizoplane, rhizosphere, and water samples before and after exposure to water quality treatments. Functional community changes were determined using Biolog™ EcoPlates which assess community-level carbon source utilization profiles. Wetland mesocosm removal of inorganic nutrients (N, P) and fecal coliforms was also determined, and compared among treatments. Treatment-specific effects were assessed using a repeated measures restricted maximum likelihood (REML) analysis. Structural and functional characteristics of rhizoplane microbial communities were significantly influenced by the interaction between plant species and water treatment (P = 0.04, P = 0.01). Plant species-specific effects were observed for rhizosphere structural diversity (P = 0.01) and wetland water community metabolic diversity (P = 0.03). The effect of water treatment alone was significant for structural diversity measurements in wetland water communities (P = 0.03). The effect of plant species, water quality treatment, and the interaction between the two is dependent on the microhabitat type (rhizoplane, rhizosphere, or water). Rhizoplane communities appear to be more sensitive to water quality-specific environmental changes and may be a good candidate for microbial community-based monitoring of wetland ecosystems.

Microhabitat Factors Influenced the Prevalence of Pathogenic Leptospira spp. in Small Mammal Host.

Leptospirosis, a widespread zoonotic disease, is a public health problem, especially in major urban centres, and is mainly reported to be associated with rats. In Malaysia, focus has been primarily given to the Leptospira prevalence in rodents per se, but there is lack of information on the microhabitat structure of the outbreak areas. We aimed to determine the diversity of small mammal species, microhabitat types, and their prevalence of pathogenic Leptospira spp. in the outbreak areas, which were categorized as urban, semi-urban, and recreational forests. Sampling involved deploying 100 to 300 live traps at each study site. Kidney samples were extracted from selected individuals, for screening of pathogenic Leptospira spp. by PCR. Out of 537 individuals from 15 small mammal species captured, 4 species were recorded from urban, 13 from semi-urban, and 11 from recreational forest sites. From 389 individuals screened, 58 were tested positive for pathogenic Leptospira. Recreational forests recorded the highest prevalence with 19.4% (n = 93), followed by urban, 16.6% (n = 163) and semi-urban sites with 9.8% (n = 133). Seven rodent species were tested positive for pathogenic Leptospira from all areas. R. norvegicus was found to harbour the highest prevalence (66.7%) in urban, R. rattus (53.8%) in semi-urban, whereby M. whiteheadi (44.4%) in recreational forest sites. Microhabitat analysis revealed that rubbish quantity contributed especially strongly to a high prevalence of Leptospira. This study contributes to understanding of the host and microhabitat preferences of Leptospira, which is important in controlling the spread of this disease in human's landscapes.

Nothing else matters? Tree diameter and living status have more effects than biogeoclimatic context on microhabitat number and occurrence: An analysis in French forest reserves.

Managing forests to preserve biodiversity requires a good knowledge not only of the factors driving its dynamics but also of the structural elements that actually support biodiversity. Tree-related microhabitats (e.g. cavities, cracks, conks of fungi) are tree-borne features that are reputed to support specific biodiversity for at least a part of species’ life cycles. While several studies have analysed the drivers of microhabitats number and occurrence at the tree scale, they remain limited to a few tree species located in relatively narrow biogeographical ranges. We used a nationwide database of forest reserves where microhabitats were inventoried on more than 22,000 trees. We analysed the effect of tree diameter and living status (alive or dead) on microhabitat number and occurrence per tree, taking into account biogeoclimatic variables and tree genus. We confirmed that larger trees and dead trees bore more microhabitats than their smaller or living counterparts did; we extended these results to a wider range of tree genera and ecological conditions than those studied before. Contrary to our expectations, the total number of microhabitat types per tree barely varied with tree genus–though we did find slightly higher accumulation levels for broadleaves than for conifers–nor did it vary with elevation or soil pH, whatever the living status. We observed the same results for the occurrence of individual microhabitat types. However, accumulation levels with diameter and occurrence on dead trees were higher for microhabitats linked with wood decay processes (e.g. dead branches or woodpecker feeding holes) than for other, epixylic, microhabitats such as epiphytes (ivy, mosses and lichens). Promoting large living and dead trees of several tree species may be a relevant, and nearly universal, way to favour microhabitats and enhance the substrates needed to support specific biodiversity. In the future, a better understanding of microhabitat drivers and dynamics at the tree scale may help to better define their role as biodiversity indicators for large-scale monitoring.

Habitat use and vestibular system's dimensions in lacertid lizards.

The vestibular system is crucial for movement control during locomotion. As the dimensions of the vestibular system determine the fluid dynamics of the endolymph and, as such, the system's function, we investigate the interaction between vestibular system size, head size and microhabitat use in lizards. We grouped 24 lacertid species in three microhabitat types, we acquired three-dimensional models of the bony vestibular systems using micro-computer tomography scanning, and we performed linear and surface measurements. All vestibular measurements scale with a negative allometry with head size, suggesting that smaller heads house disproportionally large ears. As the sensitivity of the vestibular system is positively related to size, a sufficiently large vestibular system in small-headed animals may meet the sensitivity demands during challenged locomotion. We also found that the microhabitat affects the locomotor dynamics: lizards inhabiting open microhabitats run at higher dimensionless speeds. On the other hand, no statistical relationship exists between dimensionless speed and the vestibular system dimensions. Hence, if the vestibular size would differ between microhabitats, this would be a direct effect (i.e. imposed, for instance, by requirements for manoeuvring, balance control, etc.), rather than depending on the lizards' intrinsic running speed. However, we found no effect of the microhabitat on the allometric relationship between head and vestibular system size. The finding that microhabitat is not reflected in the vestibular system size (hence sensitivity) of the lacertids in this study is possibly due to spatial constraints of the skull.

An experimental test of the multi-scalar impacts of digging mammal reintroductions on invertebrate burrows

The decline of ecosystem engineers alters ecosystems, with impacts cascading through to other organisms. Through engineering and predation, digging mammals may affect burrowing invertebrate assemblages, leading to changes in invertebrate-driven soil engineering. Using a mammal reintroduction sanctuary in southern Australia, we tested how digging mammals alter invertebrate burrows (density and size of burrow entrances) and whether these impacts were scale-dependent. We examined the micro-site (pit-scale) effects of mammal foraging pits on invertebrate burrowing activity by comparing natural and artificial pits and bare-ground, and artificial pits of different dimensions within different microhabitat types. To test how mammals affected invertebrate burrows and soil physical and chemical properties at larger scales, we used an exclusion experiment (plot-scale) and surveys inside and outside a reintroduction reserve (landscape scale). Invertebrate burrows were more numerous in mammal pits than bare-ground and artificial pits, and larger in mammal pits than bare-ground. The density and size of invertebrate burrows depended on pit morphology, with burrow density greatest in narrow bilby pits and large burrows favoured by bettong pits. However, the influence of foraging pits on invertebrate burrows was scale-dependent: changes in invertebrate burrows were not detected at the plot or landscape scale. Only 4.5% of land surface area was occupied by pits and this might be insufficient to alter burrow or soil properties detectably in un-stratified surveys at larger scales. Digging mammals altered the small-scale (but not large-scale) distribution of invertebrate burrows, suggesting that their reintroduction provides an avenue through which to restore the heterogeneity of other organisms and functions in ecosystems.

Soil bacterial community characteristics under different microhabitat types on Maolan karst forest, Guizhou, Southwest China

We analyzed the diversity, community composition and relative abundance of soil bacteria communities in five different types of microhabitats (included stone caverns, stone crevices, stone gullies, stone grooves, top-soils) in Maolan karst forest, Guizhou Province, China. Bacterial 16S rRNA V3-V4 variable regions were analyzed by high-throughput sequencing technique. We examined the effects of soil physicochemical factors on bacterial community structure. The results showed that 27 phyla, 64 classes, 128 orders, 242 families, 367 genera, and 704 species were detected in the soils from five types of microhabitats. Proteobacteria, Actinomycetes, Acidobacteria, Chlorofleixi and Nitrospirae were the dominant bacterial phyla. Actinomycetes was the dominant phyla in the microhabitats of top-stone cavern (0-10 cm), sub-stone cavern (10-20 cm), stone crevice, and stone groove. Acidobacteria was the dominant phyla in the top-soil (0-10 cm) and the sub-soil (10-20 cm). Proteobacteria was the dominant phyla in the top-stone gully (0-10 cm) and the sub-stone gully (10-20 cm). The highest soil bacterial Simpson index was found in stone crevice microhabitat, while the lowest was found in sub-soil (10-20 cm) microhabitat. Results from the LEfSe analysis showed that the number of distinct indicator species at the different levels of taxo-nomy was higher in the top-soil (0-10 cm), sub-soil (10-20 cm), sub-stone cavern (10-20 cm), and the stone groove than in the stone crevice, the top-stone gully (0-10 cm) and sub-stone gully (10-20 cm). The indicator phyla were Actinobacteria and Chlorofleixi in the sub-stone cavern (10-20 cm). The top-stone gully (0-10 cm) were characterized by the phyla of Proteobacteria and Tectomicrobia. The top-soil (0-10 cm) was featured by Acidobacteria, Verrucomicrobia and Latescibacteria. The sub-soil (10-20 cm) was dominated by Nitrospirae. There were no indicator species in stone groove, stone crevice, and sub-stone gully (10-20 cm). There was no indicator species in phylum to genus in top-stone cavern (0-10 cm). RDA and ABT analysis showed that soil organic matter, pH, and available phosphorus explained a large part of the variation regarding the responses of bacterial community to the changes in basic physicochemical factors in the soil.

茂兰喀斯特森林小生境类型对土壤微生物群落组成的影响

茂兰喀斯特森林小生境类型对土壤微生物群落组成的影响

Patterns of tree microhabitats across a gradient of managed to old-growth conditions

An inventory of tree microhabitats was done in two unmanaged forests (Kobile and Ravna gora forest reserves) and one managed beech forest in SE Slovenia. The purpose of this study was to determine the influence of forest management, natural disturbances, and tree characteristics on microhabitat patterns. Forest structure and microhabitats were recorded in systematically placed plots (500 m2 in size) across each area. In total, we inventoried 849 trees on 54 plots and 1833 tree microhabitats. The results showed that forest management had no significant influence on the abundance of microhabitats per tree, but there were differences regarding microhabitat type between managed and unmanaged sites. There were substantially more microhabitats related to standing dead and live habitat trees in unmanaged forest (e.g. woodpecker cavities, insect galleries and bore holes, branch holes, dead branches and fruiting bodies of fungi), whereas in managed forests there were more tree microhabitats related to management (e.g. exposed heartwood, coarse bark, and epiphytic plants). The results also indicate that disturbance, tree diameter, vitality, and species influence the density, diversity, and occurrence of tree microhabitats.

Local and landscape level variables influence butterfly diversity in critically endangered South African renosterveld

Severe losses in biodiversity hotspots reduce global insect diversity. Renosterveld is a critically endangered and biologically diverse ecosystem occurring only in the fynbos biome of the Cape Floristic Region (CFR), a recognized global biodiversity hotspot. Following agricultural intensification, less than 5% natural renosterveld vegetation remains in the Swartland of South Africa’s Western Cape. Remaining renosterveld is highly fragmented and confined to land less suited to agriculture, including steep slopes and rocky outcrops. These fragments vary in their environmental conditions at the local (e.g. microhabitat, floral diversity and density) and the landscape (e.g. patch size, habitat connectivity and surrounding crop cover) level. The influence of these environmental variables on butterfly diversity at a landscape scale in the CFR is not fully understood. We selected 32 sites across the Swartland and surveyed for butterflies to determine the effect of environmental variables on butterfly diversity, specifically butterfly species richness, abundance and composition. Overall, we found 2861 individuals of 27 species. Our findings suggest that crop cover in the surrounding landscape affects butterfly diversity at a small landscape scale (< 500 m radius) in the CFR. Flower species richness and microhabitat type impact species richness and abundance. Patch size is a key predictor of species diversity particularly for endemics and site quality may influence species composition. All renosterveld patches regardless of size and site quality can be considered valuable for butterflies in this highly fragmented landscape.

How close is microhabitat and diet association in aquatic ecomorphotypes? A test with tadpoles of syntopic species

Tadpoles are important components of food webs at aquatic ecosystems; however, their trophic roles remain understudied compared to fish. Morphology indicates general aspects of tadpole diets (e.g., food size), but a fine association between preferred microhabitats and diet composition remained to be tested. We tested whether syntopic tadpoles differed in microhabitat use and in diet composition according to food availability in different microhabitats. We also tested whether types of microhabitats were consistent in food availability or if food availability would vary among streams. Considering volumes of different food groups ingested, the diets of tadpoles could be partly explained by the microhabitats where they were sampled, but not by streams or even species. Considering number of items of each food group, the diet of tadpoles varied according to stream, microhabitat, and species. Volumes of items of each food group differed among microhabitats, but not among streams. All the studied species could be classified as primary consumers based on the dominance of algae (especially Zygnematophyceae and Bacillariophyceae) in their diets. Patterns of food consumption of tadpoles were complex and responded to variables at a very fine spatial scale, suggesting that they may be sensitive even to small alterations in stream dynamics.

Environmental and spatial factors affect the composition and morphology of tadpole assemblages

Understanding how community compositions are affected by environmental and spatial factors are essential to provide knowledge about the distributions of species. Furthermore, these factors can play a role in species morphological variation. Tadpoles can be found in different types of aquatic microhabitats, showing a considerable amount of morphological diversity. We hypothesized that tadpole morphological diversity is controlled by ecological and spatial factors other than assemblage attributes, and that tadpole assemblage composition is affected by spatial factors. To test these hypotheses, we recorded the abundance of tadpoles from different ponds, identified eight environmental variables that represented local and landscape descriptors of the ponds, recorded the spatial coordinates of the ponds, and measured the morphological variation of assemblages. Spatial factors significantly affected the composition of tadpole assemblages, while both spatial and environmental factors affected morphological variation. The ability of tadpoles to alter their morphology in response to environmental factors might be a result of poor oviposition site choice, and this probably interacts with spatial factors to control the assemblage composition of tadpoles. Morphological variation is advantageous for tadpoles because it allows them to adjust their morphology to environmental conditions. This study has demonstrated how factors that control the assemblage composition of tadpoles also drive their morphological diversity.