Habitat Abundance Research Articles

Age and reproductive status determine spatial niche utilization in Vipera ammodytes (Linnaeus, 1758)

While data on habitat use of Vipera ammodytes are abundant, most studies are purely descriptive and only list the typical habitats in which the species is found. The intraspecific variations (i.e., ontogenetic and intersexual) in habitat and microhabitat utilization remain very poorly studied. In order to assess those intraspecific variations, we studied five different populations in western Bulgaria between 2014–2017, searching for vipers from early spring to late autumn in 24 different habitat types. The ontogenetic and intersexual variations in spatial niche breadth were analysed using several ecological diversity indices, and microhabitat characteristics were estimated by the presence of trees/shrubs, grasses and stones/rocks within a 5 m diameter of each viper’s location. Vipers were found in 17 habitat types. Habitat and microhabitat selection of Vipera ammodytes were age-dependent, with juveniles having the narrowest spatial niche and preferring more open microhabitats. The breadth of the spatial niche gradually increased with age, along with the tendency to inhabit microhabitats with more shrubs. During gestation, female’s spatial niche narrowed significantly and pregnant vipers again tended to use more open microhabitats, known as rookery. The observed results could be explained by a combination of factors, such as 1) the ontogenetic differences in the trophic niche and feeding patterns, 2) different prey type abundance in distinct habitats and microhabitats, 3) the size differences between age groups with all benefits and limitations that come with them, 4) distinct behavioural patterns differing between sex/age groups or 5) a size-related bias in detection probabilities.

Reeve’s Muntjac (Muntiacus reevesi) Habitat Suitability Under Climate Change Scenarios in Hupingshan National Nature Reserve, China

Climate change and human disturbance are critical factors affecting the habitat distribution of wild animals, with implications for management strategies such as protecting migration corridors, habitat restoration, and species conservation. In the Hupingshan National Nature Reserve (NNR), Reeve’s muntjac (Muntiacus reevesi) is a key prey species for the South China tiger (Panthera tigris amoyensis), which is extinct in the wild and targeted for reintroduction by the Chinese government. Thus, understanding the habitat distribution and abundance of Reeve’s muntjac is essential to ensure the survival and sustainability of reintroduced tiger populations. Despite significant conservation efforts, the impacts of climate change and human disturbance on Reeve’s muntjac habitat distribution in Hupingshan NNR remain unclear, though these factors could necessitate adaptive tiger management strategies due to shifts in prey abundance. In this study, we employed an optimized MaxEnt model to assess current habitat distribution and identify key environmental variables influencing the habitat distribution of Reeve’s muntjac. Assuming non-climatic environmental factors will remain constant over the next century, we projected future habitat distribution under two shared socioeconomic pathways (SSP126 and SSP585) for the mid-century (2050s) and the late-century (2090s). Comparative analyses of current and projected habitat areas revealed potential impacts of climate change on this species. MaxEnt outputs classified habitat suitability into high, medium, and low levels. Results showed that climatic and human disturbance factors contributed 35.2% and 49.4% to habitat suitability, respectively. Under the SSP126 scenario, habitats with decreased suitability covered 0 km2 in the 2050s, expanding slightly to 4.2 km2 in the 2090s, while those with increased suitability spanned 491.1 km2 (2050s) and 463.2 km2 (2090s). Under the SSP585 scenario, habitats with decreased suitability covered 10.2 km2 in the 2050s and 431.8 km2 in the 2090s. Habitats with increased suitability were comparatively smaller under SSP585, covering 162.0 km2 (2050s) and 1.1 km2 (2090s). These findings suggest that while mid-century climate projections (SSP126 and SSP585) may support Reeve’s muntjac’s survival, habitat loss is projected by 2090s (SSP126). Thus, future climate change may lead to decreased habitat suitability and increased fragmentation, raising extinction risks for Reeves’s muntjac. Mitigating these effects could involve establishing migration corridors, minimizing human disturbances, and potentially supplementing prey populations with captive-bred prey. Such measures are essential to support the South China tiger reintroduction plan and help ensure that prey availability remains sufficient for sustaining reintroduced tiger populations.

Black fly diversity and molecular detection of blood parasites in Simulium khelangense (Diptera, Simuliidae) from Laos

Abstract Black flies (Diptera: Simuliidae) are significant pests and vectors transmitting pathogens to humans and other animals. However, knowledge of species diversity as well as their role as pests and vectors in Laos is limited, despite the country having abundant suitable lotic habitats, that is, running water. In this study, we collected wild adult black fly specimens from Laos. Both morphology and genetic data supported that they were Simulium khelangense Takaoka, Srisuka and Saeung, and therefore, a new distribution record for this species. Screening of the blood protozoa from 106 females detected Leucocytozoon (n = 7) and Trypanosoma (n = 9). Identifications of Leucocytozoon based on cytochrome b sequences in MalAvi database indicated that 5 specimens had identical sequences to those of 4 lineages (GALLUS17 [n = 2], GALLUS35 [n = 1], GALLUS37 [n = 1], and GALLUS41 [n = 1]) of unidentified species (i.e., Leucocytozoon sp.). The remaining 2 had no identical sequences but were very similar (99%) to GALLUS34 and GALLUS41 lineages. Identifications of Trypanosoma based on the small subunit rRNA indicated that all were T. avium. The results presented here further support the role of S. khelangense as a potential vector of Leucocytozoon and Trypanosoma as well as being a possible pest of domestic avian species.

Molecular identification of tick (Acari: Ixodidae) and tick-borne pathogens from Przewalski's gazelle (Procapra przewalskii) and Tibetan sheep (Ovis aries) in Qinghai Lake National Nature Reserve, China

The Qinghai Lake National Nature Reserve (QLNNR), renowned for its abundant natural resources and diverse ecological habitats, serves as an ideal environment for ticks, thereby increasing the risk of various tick-borne pathogens (TBPs) transmission. This study aimed to investigate the prevalence of TBPs in ticks collected from Przewalski's gazelle and Tibetan sheep within the QLNNR. A total of 313 tick samples were collected from the vicinity of Qinghai Lake. Tick species identification was conducted using both morphological and molecular biology techniques. Polymerase chain reaction (PCR) amplification was performed to detect the presence of spotted fever group (SFG) Rickettsia, Coxiella burnetii, Anaplasma phagocytophilum, Babesia microti, Theileria spp, Borrelia burgdorferi, Brucella spp, and Anaplasma ovis was performed using specific primers. Positive samples were sequenced and analyzed using BLASTn, followed by phylogenetic tree construction. The ticks collected from the Qinghai Lake area were identified as Dermacentor nuttalli. The overall prevalence rates of ticks carrying SFG Rickettsia and C. burnetii were 42.8% (134/313) and 4.8% (15/313), respectively. Three SFG Rickettsia species were detected, including R. raoultii 33.9% (106/313), R. slovaca 3.8% (12/113) and R. sibirica 7.7% (24/113), with R. raoultii being the predominant species. The prevalence rates of SFG Rickettsia and C. burnetii in ticks from Tibetan sheep was 44.7% (115/257) and 4.7% (12/257), respectively,and in ticks from Przewalski's gazelle were 33.9% (19/56) and 5.4% (3/56). Furthermore, the study revealed a positive linear relationship between the abundance of Przewalski's gazelle and the number of ticks, as well as the prevalence of TBPs. The current study has identified Dermacentor nuttalli as the predominant tick vector species within the QLNNR region. The detection of SFG Rickettsia and C. burnetii has augmented our understanding of the epidemiological profile of ticks and TBPs in this area, thereby providing a robust theoretical foundation for the implementation of effective prevention and control strategies against TBPs.

Development of a localized Web-based GIS Visualization Platform as a tool for Disseminating Habitat Abundance of Aedes Mosquito Vectors in the Philippines

Abstract. Disseminating up-to-date information on dengue mosquito habitats aided by modern GIS approach would yield benefits to people being informed on the localized developments of the vector and therefore reduce people’s risk of being affected by the disease. This paper discusses the development of this monitoring and sensing mechanism through a Web-based GIS mapping and visualization. It utilizes the environmental, WHO dengue indices and weather information for a case of a city in the Philippines to visualize hotspot areas for habitats of dengue vectors. The paper would aid the government in deploying key assets and supporting DOH’s 5S drive or Search, Self, Seek, Support and Sustain strategy to curtail the spread of the disease. Through this paper, the author intends to develop a localized web-based platform Aedes mosquito vector. Presented in this study provides the data workflow from field observations and the inputs from environmental and meteorological data which has the potential to help enhance the data dissemination as well as the IEC campaign of local health leaders in reducing the mortality and morbidity of people affected by Dengue mosquitoes. This visualization platform includes an easy to set-up system using the available Web-based GIS which can be updated depending on the availability of field data and meteorological observations.

Correction to: The impact of coral reef habitat and microbial abundance status on sponge-associated prokaryotic communities

Correction to: The impact of coral reef habitat and microbial abundance status on sponge-associated prokaryotic communities

Great ape abundance and per capita carbon storage in their habitats

The ecological importance of great apes is widely recognised, yet few studies have highlighted the role of protecting great apes’ habitats in mitigating climate change, particularly through carbon sequestration. This study used GIS tools to extract data from various sources, including the International Union for Conservation of Nature database, to examine carbon quantity and great ape abundance in African great ape habitats. Subsequently, we employed a generalised linear model to assess the relationship between locally measured great ape populations abundance and carbon storage across areas with different levels of protection. Our findings showed a positive relationship between the abundance of great apes in their habitats and carbon storage, likely since conservation efforts in great apes habitats may be strengthened with higher great ape populations. The results reveal that gorilla habitats exhibited higher carbon storage than chimpanzee habitats. Specifically, the areas inhabited by gorillas are associated with a mean increase of 27.47 t/ha in carbon storage. Additionally, we observed a positive association between highly protected areas and carbon storage within great ape habitats. Our model indicates that highly protected areas increase the mean carbon stored by 1.13 t/ha compared to medium protected areas, which show a reduction of 15.49 t/ha. This highlights the critical role that protected areas play in both species conservation and carbon sequestration, contributing significantly to climate mitigation efforts. Furthermore, our study underscores the significant contribution of great ape habitats, extending beyond protected areas, to carbon storage, highlighting the potential for synergistic conservation strategies targeting both great apes and carbon sequestration. Protecting great apes is vital for reducing carbon emissions from deforestation and boosting tropical forest carbon sinks. Since nearly 90% of great apes live outside protected areas, targeted conservation in these low-protected areas is also crucial.

The impact of coral reef habitat and microbial abundance status on sponge-associated prokaryotic communities

AbstractSponges are one of the oldest lineages of animals on Earth and play key roles in shaping marine ecosystems. They are diverse, with more than 9600 species known to science, and come in a wide range of shapes, sizes, and colours. Sponges are, furthermore, known to host diverse communities of microbial symbionts, which play important roles in their physiology and ecology. In the present study, we sampled prokaryotic communities from 24 sponge species inhabiting coral reef flat and slope habitats off the coast of SW Celebes (Indonesia) in addition to sediment and seawater. The prokaryotic profiles of several sponge species were characterised for the first time. In line with previous studies, we revealed pronounced variation in diversity and composition among species with high microbial abundance (HMA) or low microbial abundance (LMA) status playing an important role in structuring prokaryotic communities across host sponge species. In addition to this, reef habitat (flat versus slope) also played a significant role in structuring prokaryotic communities. Most species in the reef slope habitat housed prokaryotic communities with a consistent profile of several cyanobacterial and prokaryotic OTUs, whereas these OTUs were largely absent from sponges inhabiting the reef flat habitat. Instead, they tended to house highly abundant bacterial populations related to the Synechococcus spongiarum group. We propose that specific strains of S. spongiarum may play a key role in enabling their host sponges to survive in an, otherwise, inhospitable environment (e.g., high irradiance and temperature) and, thus, help to explain differences in sponge composition between coral reef flat and slope habitats.

Effects of Breeding Habitat on the Abundance and Body Condition of Two <i>Pelophylax</i> Species in Agriculture and Urban Landscapes

Amphibians play a key role in structuring biological assemblages of agricultural landscapes, but they are threatened globally by agricultural intensification. Numerous studies have considered the morphology of animals to be an indicator of the health of a population, but data about the differences in amphibian morphology in different breeding habitats in agricultural landscapes are still missing. Here, we investigated the differences in the abundance and morphology of Pelophylax plancyi and Pelophylax nigromaculatus in the three waterbody types: fields, forests, and parks in agricultural landscapes in Nanjing, China. Our results emphasize that both frog species in forests and parks had significantly higher body condition indexes than those in fields, whereas their abundance in fields habitat was higher than those of the two other habitat types. Our results demonstrated the importance of non-agricultural habitats (such as forests and parks) in agricultural landscapes to the persistence of both Pelophylax species. We recommend preserving field ecosystems by constructing diverse waterbodies other than fields in rural areas and maintaining microhabitats in parks and forests to improve amphibian biodiversity in Nanjing.

First use of Chironomid Pupal Exuvial Technique in freshwater biomonitoring in Cameroon: Ecological aspect and morphological description of Chironomidae (Insecta: Diptera)

The biodiversity of urban streams is gradually degrading as a result of anthropogenic pollution. In this study, chironomid pupal exuviae were used as surrogates to assess urban streams and a lake in Douala Cameroon. We compared these assessments with samples collected from a suburban forest stream. Based on their highly adaptive capability, we predicted that chironomid communities would present high diversity and abundance in urban habitats. Chironomid pupal exuviae were collected using the chironomid pupal exuvial technique in 14 urban and 2 forest reference stations during dry and rainy seasons. Measurements of the environmental variables were done simultaneously. Physicochemical analysis revealed that all urban sites have had very poor ecological health status whereas forest site had good water quality as shown by the hierarchical cluster analysis. This ecological survey identified 8 species/morphotypes of chironomids all belonging to the subfamily Chironominae, tribe Chironomini. These are Chironomus holomelas(?), Chironomus sp.1, Chironomus sp.2, Chironomus sp.3, Chironomus (Lobochironomus) sp., Stenochironomus sp., Dicrotendipes sp. and Dicrotendipes pulsus. No midge pupal exuviae were recorded at the forest stations (S1 & S2) and the stations S6 and S7 located downstream industrial mill effluents. The species richness of the study sites was significantly very low as compare to other Afrotropical studies. Canonical redundancy analysis revealed that high values of water temperature, ammonium, nitrates and phosphates, and low oxygen concentration were significant predictors of the distribution and high abundance of Chironomidae. This survey highlighted the impacts of anthropogenic activities on chironomid diversity and distribution, with great decrease of their diversity due to industrial pollution.

From small water bodies to lakes: Exploring the diversity of freshwater bacteria in an Alpine Biosphere Reserve

Small water bodies, although supporting high biodiversity, are often understudied in the Alpine region. In this work, we characterized the planktic and benthic bacterial communities, as well as the water chemistry, of a wide physiographic range of 19 freshwater bodies within an Alpine Biosphere Reserve, including ponds, pasture ponds, peat bogs, shallow lakes, and lakes. We collected both water and surface sediment samples, followed by metabarcoding analysis based on the V3-V4 regions of the 16S rRNA gene. We investigated the changes in biodiversity and the distribution of unique and shared amplicon sequence variants (ASVs) between water (11,829 ASVs) and surface sediment (19,145 ASVs) habitats, as well as across different freshwater typologies. The majority of ASVs (78 %) were unique to a single sample, highlighting the variability and uniqueness of bacterial communities in such freshwater bodies. Most freshwater environments showed higher α-diversity in sediment samples (median, 1469 ASVs) compared to water (468 ASVs). We found that water and sediment habitats harboured unique bacterial communities with significant differences in their taxonomic compositions. Benthic bacteria were associated with several biogeochemical and degradative processes occurring in the sediments, with no notable differences among freshwater typologies and with phylogenetically and ecologically similar species. Conversely, planktic communities showed greater heterogeneity: small water bodies and peat bogs were characterized by higher relative abundances of Patescibacteria (up to 33 %), while lakes and shallow lakes were dominated by Actinobacteriota (up to 36 %). Cyanobacteria (426 ASVs) were generally distributed at low abundances in both water and sediment habitats. Overall, our results provided essential insights into the bacterial ecology of understudied environments such as ponds and pasture ponds and highlighted the importance of further exploring their rich pelagic and benthic bacterial biodiversity.

Abiotic factors shape mosquito microbiomes that enhance host development.

Metazoans rely on interactions with microorganisms through multiple life stages. For example, developmental trajectories of mosquitoes can vary depending on the microorganisms available during their aquatic larval phase. However, the role that the local environment plays in shaping such host-microbe dynamics and the consequences for the host organism remain inadequately understood. Here, we examine the influence of abiotic factors, locally available bacteria, and their interactions on the development and associated microbiota of the mosquito Aedes albopictus. Our findings reveal that leaf detritus infused into the larval habitat water, sourced from native Hawaiian tree "ōhi'a lehua Metrosideros polymorpha, invasive strawberry guava Psidium cattleyanum, or a pure water control, displayed a more substantial influence than either temperature variations or simulated microbial dispersal regimes on bacterial community composition in adult mosquitoes. However, specific bacteria exhibited divergent patterns within mosquitoes across detrital infusions which did not align with their abundance in the larval habitat. Specifically, we observed a higher relative abundance of a Chryseobacterium sp. strain in mosquitoes from the strawberry guava infusion than the pure water control, whereas the opposite trend was observed for a Pseudomonas sp. strain. In a follow-up experiment, we manipulated the presence of these two bacterial strains and found larval developmental success was enhanced by including the Chryseobacterium sp. strain in the strawberry guava infusion and the Pseudomonas sp. strain in the pure water control. Collectively, these data suggest that interactions between abiotic factors and microbes of the larval environment can help shape mosquito populations" success.

Oral Microbiota and the Risk of Gastrointestinal Cancers-A Narrative Literature Review.

The human body is colonized by trillions of microorganisms in a symbiotic relationship. The oral cavity represents one of the most abundant microbial habitats in our body. Advances in sequencing techniques provide a more detailed understanding of the oral microbiota and how imbalances between bacteria, the phenomenon of dysbiosis, can affect not only the development of dental caries or inflammation within the oral cavity but also systemic diseases and cancers in distant locations. This narrative review evaluates the relationship between oral microbiota and its impact on gastrointestinal cancers. Using the keywords "oral microbiota 'AND' gastrointestinal cancers", the PubMed Web of Science and Scopus databases were searched for articles published between 2014 and 2024. Based on the review, the relationship between oral microbiota and oral, esophageal, gastric, colorectal, hepatocellular, and pancreatic cancers was described. Potential oncogenic mechanisms exploited by the microbiota such as the production of pro-inflammatory cytokines, induction of abnormal immune responses, and disruption of cell metabolic pathways were assessed. Further research and a thorough understanding of the impact of the oral microbiota on the development of cancers of the gastrointestinal tract may play a key role in their prevention, diagnosis, and treatment in the future.

Mitochondrial markers revealed genetic panmixia in the data-deficient yellowfin snapper, Lutjanus xanthopinnis (Actinopterygii: Eupercaria: Lutjanidae), from a hotspot of the southern region of the South China Sea

Understanding the genetic structure and diversity of marine fish is crucial for a sustainable management program. We examined the genetic diversity and historical demographics of the yellowfin snapper, Lutjanus xanthopinnis Iwatsuki, Tanaka et Allen, 2015, in the coastal waters of east Peninsular Malaysia which is bordered by the southern part of the South China Sea using the mitochondrial genes (mtDNA) D-loop and Cytochrome b (Cyt-b). A total of 99 (D-loop) and 78 (Cyt-b) specimens of L. xanthopinnis were successfully sequenced from six locations within the range of species distribution along the Malaysian South China Sea. In the presently reported study, the lack of genetic differentiation among populations can be attributed to historical demographic events, eggs and planktonic larvae’ ability to disperse, spawning patterns, and the absence of physical barriers in the geographical landscape. Maximum likelihood gene trees demonstrated that the populations under study had limited structuring and formed a panmictic population that lacks support for internal clades. The AMOVA (Analysis of Molecular Variance) and population pairwise ФST values indicated high genetic exchange between the study areas. A high level of haplotype diversity (D-loop: 0.948–1.000; Cyt-b: 0.542–0.928), low nucleotide diversity (D-loop: 0.0095–0.0159; Cyt-b: 0.0022–0.0049) and starlike haplotype network indicates a recent expansion of L. xanthopinnis populations in Malaysian South China Sea. However, neutrality and goodness of fit tests revealed non-significant values. Furthermore, the BSP (Bayesian skyline plot) analysis estimated population expansion events during the late Pleistocene. During this epoch, the fluctuation in sea level may have led to an increase in the abundance of resources and favorable habitats for the yellowfin snapper. The presently reported findings could initiate efficient management strategies for L. xanthopinnis along the coastal areas of the Malaysian South China Sea and other nearby nations that share the same waterways.

Age and growth of a habitat-forming deep-sea coral Solenosmilia variabilis in the New Zealand region: implications for fisheries management

ABSTRACT One of the most widespread and abundant habitat forming deep-sea corals in the South Pacific region is Solenosmilia variabilis. The age of this species was assessed using radiocarbon content (14C) on long dead, recently dead, and live branch sections of coral reef matrix sampled from the New Zealand region. Conventional 14C colony ages (yrs BP), for the living, recently dead, and long dead samples, ranged from 803 to 1186 years (Graveyard Knolls, Chatham Rise), and 907 to 11, 694 years (Louisville Seamount Chain east of New Zealand). Overall calendar ages, ranged from 84 to 292 years, and similar linear and step-wise growth rate data were obtained. Linear growth ranged from 0.2 to 1.3 mm/yr. From a conservative estimate of matrix height of ∼20 cm, it could take hundreds of years (∼150–660) of growth for a colony of S. variabilis to attain this height, and around ∼2000 years to build a colony diameter of 1 metre. Defining the age, growth and recovery timeframes of deep-sea coral can inform risk assessments of the level of susceptibility to trawling activity and their potential to recover, as well as provide options for the considered management of deep-sea habitats.

Distribution of Carbon-Sequestering Microbes in Different Habitats and the Interaction with Habitat Factors in a Natural Karst Cave

The distributional characteristics of microorganisms in karst cave ecosystems have been widely studied. However, in such a dark, humid, and oligotrophic habitat, studies on the differences in carbon-sequestering bacteria in multiple habitats are limited. Therefore, to learn the distribution characteristics of carbon-sequestering colonies in cave habitats and their correlation with habitat factors (e.g., pH, Ca2+, Mg2+, etc.), samples from five cave habitats (weathered rock walls, underground river water, drips, sediments, and air) were collected from the twilight and dark zones of Shiziyan Cave (CO2 concentration 5385 ppm). The results of high-throughput sequencing and statistical analyses showed that there were significant differences in the distribution of communities in different habitats, with higher abundance in sediments habitat and underground river water habitat, and the dominant phyla of Pseudomonadota (30.53%) and Cyanobacteria (75.11%) in these two habitats. The microbial diversity of the carbon-sequestering microbial community was higher in sediments than in underground river water. The pH, and Ca2+, SO42−, and NO3− concentrations can alter the diversity of carbon-sequestering microbes, thereby affecting carbon cycling in caves. Carbon metabolism analyses suggest that microbes in the habitat can cooperate and coexist by participating in different carbon metabolic pathways. These results expanded our understanding of carbon-sequestering microbial communities in cave systems and their responses to the environment.

Anatomy of a post-wildfire recovery: Responses of mammals to a Black Summer wildfire in a fox-free landscape

Wildfires are predicted to increase in frequency and severity with climate change. Devising effective strategies to ensure wildfires do not hasten a decline in wildlife populations hinges on developing a deeper understanding of how species are affected by recent wildfires. I investigated the response of eight species of medium-sized mammals over a 4-year period (2020–2023) following a wildfire in the Australian Black Summer fire season. Pre-wildfire population levels were not known. These species differed in their ability to survive the passage of fire; from being able to flee the fire front, to remaining in protective shelters, to favouring unburnt forest types, to none of these strategies. Camera trapping was conducted from 5 months to 4 years after the fire across 62 sites in wet and dry sclerophyll forest (burnt and unburnt) and rainforest (unburnt) to characterise both initial survival and subsequent reproduction-led post-fire occupancy. There was consistency in the response of species in year 1. Those assumed to be able to flee the fires showed medium-high post-fire occupancy regardless of whether a site was burnt. Those that use protective shelters and unburnt forest also showed high occupancy. One species without these options showed greatly reduced occupancy in year 1 relative to years 3 and 4. Most species showed evidence of increased detection across years, which is inferred to reflect increased abundance, and was expected given substantially above average rainfall for three years following the fire. The feral cat was the only predator sufficiently widespread to be of concern in species’ recovery but was rarely detected in years 1 and 2, relative to years 3 and 4. This study provides evidence that many species, including three threatened species, have the ability to survive the passage of fire, and show high post-fire occupancy. The study landscape contained abundant habitat elements (unburnt rainforest, boulder fields) that promote survival through a wildfire and post-fire recovery, providing insights to guide future conservation actions.

Investigating hydrodynamics and turbulent effects in rivers for different flow conditions using spatial complexity metrics

In non-uniform river flows, hydrodynamic features, such as gradients of velocity in flow directions, are of particular importance for explaining the abundance of aquatic habitats. Hydraulic complexity metrics referred to as M1, M2, and M3 play an important role when it comes to the analysis of habitat metrics on a 3D spatial level. Parameter M1 is proportional to the drag force experienced by an organism, parameter M2 represents how much more energy an organism must expend if it moves from the lower velocity to the higher velocity location, and parameters M3 illustrates the circulation in flow. The specific aim of the present study is to apply those parameters to characterize, under different flow conditions, the cross-sectional distribution of kinetic energy and coherent structures which are both relevant for many aquatic organisms. To this aim, laboratory data as well as field observations along Tiber River, in central Italy, were considered and the hydraulic complexity metrics were investigated in dimensionless form. On the laboratory-scale, the dimensionless parameters M1*, M2* and M3* identify the velocity gradient related to the high/low cross-sectional velocity and the high/low vorticity areas in selected cross-sections along the flume. Then, the evaluation of the parameter M2* in the horizontal plane allows to verify the relation between the localization of the high/low kinetic energy areas in the longitudinal direction. For the field-scale, the parameters were investigated, under high, moderate and low flow conditions, in a gauged site in the Tiber River. The results indicate that an aquatic organism should spend more energy where M3*, which is related to flow circulation, assumes high values. Furthermore, significant values of M1* and M2* are observed, which are linked to gradients in the cross-sectional distribution of velocity. These values are predominantly found at the river centerline for M1* and at the banks for M2*. In terms of echo-hydraulics, the results based on both laboratory and field data indicate that they are complementary, showing that for the larger magnitudes of M1 and M3, which are related to the kinetic energy and flow circulation, respectively, an aquatic organism should spend more energy in these zones. Overall, the results based on both laboratory and field studies suggest that parameters M1 and M2 are inversely linked, i.e., M1 decreased with increasing M2, while, there is no relationship between parameters M3 and M1. The findings of the present research would be of particular interest in quantifying biologically important flow patterns occurring at different spatial scales within different streams and under different flow conditions.

Adaptive stacked species distribution modelling: Novel approaches to large scale quantification of blue carbon to support marine management

This study introduces a novel concept of ‘Adaptively Stacked’ Species Distribution Models (AS-SDMs) to predict blue carbon habitat distribution, abundance, carbon stocks, and carbon sequestration potential in Orkney. AS-SDMs are built from Weighted Boosted Regression Trees (WBRTs) that adaptively stack blue carbon sediment thickness, sediment carbon content, and sequestration potential to predicted abundance. A novel method to describe substrate types by relative inputs of mud, sand, and gravel is detailed that better characterises the determining factors of seagrass, maerl, and horse mussel abundance. This study also introduces a novel use of indexes to mitigate double counting issues of mixed species distribution models.Seagrass, maerl, horse mussel, and mixed seagrass and maerl (SGM) habitats are estimated to cover a maximum area of 657 km2 in Orkney, have a total sediment carbon stock of 16 Mt. C, and sequester 6000 t C yr−1. Applying a conservative threshold of 50 % abundance to habitat predictions, six key potential areas of blue carbon offset projects are identified. These areas cover just over 9 km2, have a total carbon stock of 330,000 t C, and sequester 330 t C yr−1. When applied to UK carbon credit value, assuming integration with voluntary markets and compliance with accreditation criteria, the habitats in these areas have a potential value of £24.5 million. If applied as annual values, these areas have carbon stocks with a potential value of £0.93 million yr−1 and a carbon sequestration potential value of £24,000 yr−1.

Upland vegetation removal as a potential tool for facilitating landward salt marsh migration

To increase the resilience of salt marshes subject to sea‐level rise impacts, managers can focus on interventions within current marsh footprints or in adjacent uplands to facilitate landward marsh migration. The latter approach may be more appropriate when degradation is severe and in situ intervention options are limited. Strategies for facilitating marsh migration include removing artificial barriers, soil grading to reduce steep topography, and manipulating adjacent upland vegetation that can hinder migration, but experiments testing the effectiveness of these activities are limited. We therefore conducted a field experiment to determine if physically removing three upland vegetation types (forest, shrub, and Phragmites australis) adjacent to a Rhode Island salt marsh facilitates short‐term marsh migration. Upland vegetation removal led to increased ambient light in all habitats, significantly enhanced marsh plant cover, extent, and elevation in shrub habitat, and declines in total bird abundance in forest and shrub habitats. Enhanced migration did not occur in forest or Phragmites habitats, and in shrubs, marsh plants only colonized where Baccharis halimifolia, common in upper marsh borders, had been removed. Five years after removal, all upland habitats and associated vegetation were indistinguishable from initial conditions. Our study suggests that upland plant removal might provide a limited window for facilitating salt marsh migration and that more intensive methods may be needed for sustained, longer‐term benefits. It also demonstrates that there may be ecological trade‐offs to consider when altering upland habitats to enhance landward marsh migration.