Abundance Of Mammals Research Articles

Mapping small mammal optimal habitats using satellite-derived proxy variables and species distribution models.

Small mammal species play an important role influencing vegetation primary productivity and plant species composition, seed dispersal, soil structure, and as predator and/or prey species. Species which experience population dynamics cycles can, at high population phases, heavily impact agricultural sectors and promote rodent-borne disease transmission. To better understand the drivers behind small mammal distributions and abundances, and how these differ for individual species, it is necessary to characterise landscape variables important for the life cycles of the species in question. In this study, a suite of Earth observation derived metrics quantifying landscape characteristics and dynamics, and in-situ small mammal trapline and transect survey data, are used to generate random forest species distribution models for nine small mammal species for study sites in Narati, China and Sary Mogul, Kyrgyzstan. These species distribution models identify the important landscape proxy variables driving species abundance and distributions, in turn identifying the optimal conditions for each species. The observed relationships differed between species, with the number of landscape proxy variables identified as important for each species ranging from 3 for Microtus gregalis at Sary Mogul, to 26 for Ellobius tancrei at Narati. Results indicate that grasslands were predicted to hold higher abundances of Microtus obscurus, E. tancrei and Marmota baibacina, forest areas hold higher abundances of Myodes centralis and Sorex asper, with mixed forest-grassland boundary areas and areas close to watercourses predicted to hold higher abundances of Apodemus uralensis and Sicista tianshanica. Localised variability in vegetation and wetness conditions, as well as presence of certain habitat types, are also shown to influence these small mammal species abundances. Predictive application of the Random Forest (RF) models identified spatial hot-spots of high abundance, with model validation producing R2 values between 0.670 for M. gregalis transect data at Sary Mogul to 0.939 for E. tancrei transect data at Narati. This enhances previous work whereby optimal habitat was defined simply as presence of a given land cover type, and instead defines optimal habitat via a combination of important landscape dynamic variables, moving from a human-defined to species-defined perspective of optimal habitat. The species distribution models demonstrate differing distributions and abundances of host species across the study areas, utilising the strengths of Earth observation data to improve our understanding of landscape and ecological linkages to small mammal distributions and abundances.

Long term monitoring reveals the importance of large, long unburnt areas and smaller fires in moderating mammal declines in fire‐prone Savanna of northern Australia

Abstract Biodiversity loss is often attributable to multiple interacting pressures that are moderated across environmental gradients. These processes contribute to complex responses that are challenging to interpret and understand. Well‐designed and well‐implemented monitoring can play a vital role in this but is rarely undertaken. Mounting evidence suggests that current fire regimes across Savanna ecosystems have contributed to the decline of a range of biota. Hence, contemporary fire regimes are at odds with conservation goals. Using an extensive spatiotemporal monitoring dataset from three large National Parks in northern Australia, we applied generalised linear mixed models to examine: (1) trends in mammal richness and abundance through time and variation across environmental gradients such as productivity or landscape position (e.g. terrain ruggedness); and (2) how fire, a potential driver, is moderated by environmental gradients. Across 24 years, major declines in mammal richness and abundance were observed with greater reductions in less rugged and less mesic habitats. Patterns of decline were related to multiple aspects of fire regimes, but not changes in vegetation structure and composition, or cane toads, Rhinella marina, arrival and concomitant poisoning of predatory animals during consumption. More pronounced declines occurred in sites that were exposed to larger fires, had less long unburnt (>5 years without fire) vegetation and were more distant from large, long unburnt patches. Relationships between mammal persistence and fire varied among vegetation communities, with the strongest fire effects observed in lowland woodland—drier with few barriers to fire spread—where the availability of long unburnt areas moderated declines more than in other vegetation communities. Synthesis and applications. Current fire regimes are contributing to mammal declines in northern Australian Savanna. Collectively, our results highlight: (1) the value of long term monitoring, and importance of considering landscape position when assessing faunal responses to landscape‐level perturbations like fire; (2) that significant improvements in fire regimes are required to ameliorate mammal declines; and (3) the need to shift management focus from retaining small, short‐lived unburnt patches toward preserving relatively large contiguous areas of long unburnt habitat, particularly in less rugged lowland and sandstone woodlands.

The joint effects of forest habitat area and fragmentation on dung beetles.

Habitat loss and habitat fragmentation usually occur together, at the same time and place. However, while there is a consensus that habitat loss is the preeminent threat to biodiversity, the effects of fragmentation are contentious. Some argue that habitat fragmentation is not bad for biodiversity, and even that it is good. Generally, the studies that find no harm or positive outcomes of fragmentation invariably assume that it is independent of habitat loss. However, dissociating the effects of habitat fragmentation from habitat loss is questionable because the two are essentially coupled. Accordingly, we evaluated how forest area and fragmentation (via edge effects) influenced dung beetles per se, and through their effects on the abundance of mammals, using structural equation modeling (SEM). Dung beetles are very sensitive to forest habitat loss and fragmentation and to changes in the abundance of mammals on which they depend for dung. Our study area was in the Tana River, Kenya, where forest fragments are depauperated of mammals except for two endemic species of monkeys. We mapped 12 forests, counted the resident monkeys, and sampled 113,955 beetles from 288 plots. Most of the 87 species of beetles found were small tunnellers. After implementing a fully latent Structural Regression SEM, the optimal model explained a significant 26% of the variance in abundance, and 89% of diversity. The main drivers of beetle abundance were positive, direct, effects of forest area and number of monkeys, and negative edge effects. The main drivers of diversity were the direct effects of the beetle abundance, indirect effects of forest area and abundance of mammals, and indirect negative edge effects. Thus, forest area, fragmentation (via edge effects), and the number of monkeys jointly influenced the abundance and diversity of the beetles directly and indirectly.

Where do we manage? Uncovering the hidden impact of human presence on mammal conservation in northern Myanmar

Species spatiotemporal responses to human presence and prioritizing conservation areas are essential for effective management and conservation planning. To address this information, we conducted a long-term large mammal survey in both protected areas (PAs) and outside of PAs (non-PA) in Northern Mountain Forest Complex (NMFC), Myanmar by using 174 camera traps from 2015 to 2019. We selected 14 common species for the single species occupancy model and activity pattern analysis to evaluate their spatiotemporal responses to different anthropogenic and environmental variables. Results showed that human presence did not have a significant impact on mammal occupancy, whereas at the community level, it had a significant influence on mammal abundance. Some variables, including distance to settlements, proximity to water sources and forest cover, shaped the habitat occupancy of mammals in NMFC. Regarding the temporal axis, only three out of 14 species had higher temporal activity overlap with humans, while the remaining species showed lower to medium overlap in both PAs and non-PA, confirming that most mammals avoided human presence through temporal rather than spatial scale. Moreover, our priority analysis revealed that non-PA supported a significant proportion of medium- to high-priority areas, particularly in the south-eastern part of NMFC. We concluded that preserving both PAs and non-PA are crucial and human activities have an implicit influence on large mammal conservation in NMFC. The government should prioritize the south-eastern region of outside of the current PAs network and adopt community-based conservation strategies to ensure the efficacy of PA networks and biodiversity conservation in NMFC.

Quantifying the importance of urban trees to people and nature through tree removal experiments

Abstract Experimentally manipulating urban tree abundance and structure can help explore the complex and reciprocal interactions among people, biodiversity and the services urban forests provide to humans and wildlife. In this study we take advantage of scheduled urban tree removals to experimentally quantify the benefits that urban trees provide to humans and wildlife. Specifically, we aim to understand how trees affect: (1) bird and mammal abundance and diversity, as well as an ecological process (predation); and (2) people's perception responses, such as the importance that people assign to the trees, wildlife and the site. We designed two independent Before‐after‐control‐impact (BACI) experiments based on two sites where tree removals were occurring (impact sites): an urban park and a residential street, both located in the Greater Melbourne Area, Australia. We selected three control sites for each impact site, or four per experiment. Ecological data were collected through field surveys, and social data on people's perceptions through intercept questionnaires among park and street users. Data were analysed using a GLMMs to determine the combined effect of time (before and after) and treatment (impact and controls). At the urban park, the abundance of nectarivorous birds and possums both declined by 62% following tree removal, while invertebrate predation increased by 82.1%. The level of importance people assigned to the urban park and to the trees at the site decreased after tree removal, and people's attitudes towards tree planting became more positive, meaning more people wanted to plant more trees at the site. None of these changes were observed in the street experiment where fewer and smaller trees were removed, suggesting that effects may be highly specific to context, where factors such as tree volume, diversity and arrangement influence the magnitude of social–ecological effects observed. By demonstrating the social–ecological effect of removing urban trees, we provide evidence that urban trees provide critical habitat to urban wildlife and are perceived as an important aspect of the human experience of urban nature. Read the free Plain Language Summary for this article on the Journal blog.

Changes in over-winter prey availability, rather than winter climate, are associated with a long-term decline in a northern Tawny Owl population

Although the associations between climate, food conditions and reproduction in the wild has been the focus of numerous studies in recent years, we still know little about population level responses to climate and fluctuating food conditions in long-lived species and during longer periods of time. Here, we assessed the relative importance of the abundance of the main prey in winter (small mammals), and winter climate on population size and productivity in a Tawny Owl (Strix aluco) population in southern Finland during a 40-year period. We studied how population trends changed over time and in relation to winter weather and small mammal abundance on three levels: total estimated population size, proportion of breeders and population productivity. We identified declining trends in each population parameter over time, as well as directional changes in climate variables and prey abundance. Overall, small mammal abundance was the foremost predictor in explaining the variation in the number of active territorial pairs (population size). Moreover, both prey abundance and winter temperature significantly affected the proportion of territorial pairs that attempted to breed and thereby total offspring production, which reveals the relevance of winter weather conditions for population productivity. These results provide additional support to the view that changes in climate can modify predator–prey interactions leading to functional changes in the food web.

A camera trap method for estimating target densities of grey squirrels to inform wildlife management applications

Effective wildlife population management requires an understanding of the abundance of the target species. In the United Kingdom, the increase in numbers and range of the non-native invasive grey squirrel Sciurus carolinensis poses a substantial threat to the existence of the native red squirrel S. vulgaris, to tree health, and to the forestry industry. Reducing the number of grey squirrels, is crucial to mitigate their impacts. Camera traps are increasingly used to estimate animal abundance, and methods have been developed that do not require the identification of individual animals. Most of these methods have been focussed on medium to large mammal species with large range sizes and may be unsuitable for measuring local abundances of smaller mammals that have variable detection rates and hard to measure movement behaviour. The aim of this study was to develop a practical and cost-effective method, based on a camera trap index, that could be used by practitioners to estimate target densities of grey squirrels in woodlands to provide guidance on the numbers of traps or contraceptive feeders required for local grey squirrel control. Camera traps were deployed in ten independent woods of between 6 and 28 ha in size. An index, calculated from the number of grey squirrel photographs recorded per camera per day had a strong linear relationship (R2 = 0.90) with the densities of squirrels removed in trap and dispatch operations. From different time filters tested, a 5 min filter was applied, where photographs of squirrels recorded on the same camera within 5 min of a previous photograph were not counted. There were no significant differences between the number of squirrel photographs per camera recorded by three different models of camera, increasing the method’s practical application. This study demonstrated that a camera index could be used to inform the number of feeders or traps required for grey squirrel management through culling or contraception. Results could be obtained within 6 days without requiring expensive equipment or a high level of technical input. This method can easily be adapted to other rodent or small mammal species, making it widely applicable to other wildlife management interventions.

Tight spatial coupling of a marine predator with soniferous fishes: Using joint modelling to aid in ecosystem approaches to management

AbstractAimUnderstanding the distribution of marine organisms is essential for effective management of highly mobile marine predators that face a variety of anthropogenic threats. Recent work has largely focused on modelling the distribution and abundance of marine mammals in relation to a suite of environmental variables. However, biotic interactions can largely drive distributions of these predators. We aim to identify how biotic and abiotic variables influence the distribution and abundance of a particular marine predator, the bottlenose dolphin (Tursiops truncatus), using multiple modelling approaches and conducting an extensive literature review.LocationWestern North Atlantic continental shelf.MethodsWe combined widespread marine mammal and fish and invertebrate surveys in an ensemble modelling approach to assess the relative importance and capacity of the environment and other marine species to predict the distribution of both coastal and offshore bottlenose dolphin ecotypes. We corroborate the modelled results with a systematic literature review on the prey of dolphins throughout the region to help explain patterns driven by prey availability, as well as reveal new ones that may not necessarily be a predator–prey relationship.ResultsWe find that coastal bottlenose dolphin distributions are associated with one family of fishes, the Sciaenidae, or drum family, and predictions slightly improve when using only fish versus only environmental variables. The literature review suggests that this tight coupling is likely a predator–prey relationship. Comparatively, offshore dolphin distributions are more strongly related to environmental variables, and predictions are better for environmental‐only models. As revealed by the literature review, this may be due to a mismatch between the animals caught in the fish and invertebrate surveys and the predominant prey of offshore dolphins, notably squid.Main ConclusionsIncorporating prey species into distribution models, especially for coastal bottlenose dolphins, can help inform ecological relationships and predict marine predator distributions.

Allometry of sodium requirements and mineral lick use among herbivorous mammals

Sodium (Na) plays a critical role in the functioning of terrestrial ecosystems. In Na‐poor regions, plant consumers may experience Na deficiency and adapt by seeking supplementary Na resources. This can markedly impact animal behavior, space‐use, and co‐existence, with concomitant impacts on ecosystems. Many studies have noted that Na‐seeking behaviors, such as soil consumption from mineral licks, are predominately observed for larger‐bodied herbivores. However, the mechanisms that drive interspecific variation in Na deficiency and mineral lick use remain poorly understood. Here, we examine whether allometric scaling of Na requirements can explain variation in mineral lick use by herbivorous and omnivorous mammals. We 1) collated data from published literature to derive an allometric scaling of Na requirements in mammals, 2) compared predicted Na requirements to estimated Na intake of mammal communities in three globally distant sites: the Peruvian Amazon, Kalahari Desert, and Malaysian Borneo and 3) examined the relationship between predicted Na deficiency and mineral lick use utilizing camera‐trap and mammal abundance data at each site. We found that minimum daily Na maintenance requirements in mammals scaled allometrically at a higher factor (BM0.91 (CI: 0.80–1.0)) than that of food and water Na intake (BM0.71–0.79), indicating that larger species may be more susceptible to Na limitation. This aligned with a positive association between mineral lick use and body mass (BM), as well as Na deficiency, by species at all sites, and increased artificial salt and mineral lick consumption by larger‐bodied mammals in the Kalahari. Our results suggest that larger herbivores may be more sensitive to anthropogenic impacts to Na availability, which may alter their functional roles in ecosystems, particularly in Na‐poor regions. Further research is needed to explore the consequences of changing Na availability on animals and ecosystems, as well as advance our understanding of Na physiology in mammals.

Woody debris structures on large clearcut openings: Oases for small mustelids and prey species?

Restoration structures such as post-harvest woody debris piles on large clearcut openings may provide habitat for many mammal species. Mustelids such as the American marten (Martes americana) and several weasel (Mustela spp.) species are important furbearers in temperate and boreal forests and are negatively affected by clearcutting. We ask if constructed piles of woody debris on large (e.g., 30–50 ha) openings will be used by these mustelids and their small mammal prey species? We tested the hypotheses (H) that (H1) the presence (index of activity patterns) of small mustelids, (H2) abundance, species richness, and species diversity of the forest-floor small mammal community, and (H3) reproduction of the major species: southern red-backed vole (Clethrionomys gapperi), long-tailed vole (Microtus longicaudus), and deer mouse (Peromyscus maniculatus), would be greater on sites with woody debris piles than on sites with dispersed debris. A fourth hypothesis (H4) predicted that the above response variables would be similar across a linear configuration of debris piles on the large openings. Mustelid presence and populations of forest-floor small mammals were sampled on four replicated (n = 4) large (30–50 ha) clearcut sites from 2017 to 2022 in south-central British Columbia, Canada.Mean presence of mustelids was significantly higher (4.5 to 8.0 times) in piles than dispersed sites during the first four post-harvest years, thereby supporting H1. Mean index of mustelid activity per line was similar among pile index-lines across these clearcut openings. Mean abundance of C. gapperi was similar statistically between treatment sites but with numbers 3 to 10 times higher, on average, in the piles than dispersed sites and was likely biologically important. Mean abundance of M. longicaudus was significantly higher (1.2–4.4 times) in the piles than dispersed sites. Mean abundance of P. maniculatus and Sorex spp. were similar between treatment sites. Mean abundance of total small mammals, including the less common species, was significantly higher (1.4–1.9 times) in piles than dispersed sites. Similarly, mean species richness and diversity were both significantly higher in piles than dispersed sites. Mean number of total recruits was higher in piles than dispersed sites for M. longicaudus and P. maniculatus, but most measures of reproductive attributes were similar, thereby providing only partial support for H3. As per support for H4, response variables were similar across a linear array of debris piles on large openings. Our study is the first to measure responses of small mustelids and forest-floor small mammals to constructed piles of woody debris as a means of habitat restoration on relatively large (mean area 40.5 ha) openings created by conventional clearcutting. Piles of debris seem to act as oases for mustelids and their prey species in ecological restoration of cutover forest land.

Quantifying the direct and indirect effects of sika deer (Cervus nippon) on the prevalence of infection with Rickettsia in questing Haemaphysalis megaspinosa: A field experimental study

Sika deer (Cervus nippon) are important hosts for all life stages of Haemaphysalis megaspinosa, a suspected Rickettsia vector. Because some Rickettsia are unlikely to be amplified by deer in Japan, the presence of deer may decrease the prevalence of Rickettsia infection in questing H. megaspinosa. As sika deer decrease vegetation cover and height and thereby indirectly cause changes in the abundance of other hosts, including reservoirs of Rickettsia, the prevalence of Rickettsia infection in questing ticks can also change. We investigated these possible effects of deer on the prevalence of infection with Rickettsia in questing ticks in a field experiment in which deer density was manipulated at three fenced sites: a deer enclosure (Deer-enclosed site); a deer enclosure where deer had been present until 2015 and only indirect effects remained (Indirect effect site); and a deer exclosure in place since 2004 (Deer-exclosed site). Density of questing nymphs and the prevalence of infection with Rickettsia sp. 1 in questing nymphs at each site were compared from 2018 to 2020. The nymph density at the Deer-exclosed site did not significantly differ from that at the Indirect effect site, suggesting that the deer herbivory did not affect the nymph density by reducing vegetation and increasing the abundance of other host mammals. However, the prevalence of infection with Rickettsia sp. 1 in questing nymphs was higher at the Deer-exclosed site than at the Deer-enclosed site, possibly because ticks utilized alternative hosts when deer were absent. The difference in Rickettsia sp. 1 prevalence between the Indirect effect and Deer-exclosed sites was comparable to that between the Indirect effect and Deer-enclosed sites, indicating that the indirect effects of deer were as strong as the direct effects. Examining the indirect effects of ecosystem engineers in the study of tick-borne diseases may be more important than previously recognized.

Assemblage, relative abundance and activity pattern of wild mammals in the human-dominated landscape of Vansda taluka, Gujarat, India

Abstract Conservation of mammals in human-dominated landscapes requires essential information on their ecological aspects. We used camera traps to assess the wild mammal assemblage, their relative abundance, and activity patterns in the human-dominated landscape of Vansda taluka, Gujarat, India. We deployed 80 camera traps in square grids of 2 km2 resulting in an area coverage of 160 km2. To assess the mammal assemblage, relative abundance of species, and activity pattern, respectively, we used a count of species, relative abundance index (RAI), and circular statistics. We captured 13 mammals, including the wild pig, Indian hare, leopard, rhesus macaque, common grey mongoose, small Indian civet, common palm civet, Indian crested porcupine, hanuman langur, chital, barking deer, striped hyena, and jungle cat. The wild pig was the most abundant (RAI = 10.29), while the jungle cat was the least abundant (RAI = 0.04) species. Hanuman langur, rhesus macaque, and chital showed diurnal activity, while striped hyena, barking deer, small Indian civet, common palm civet, and Indian crested porcupine showed nocturnal activity. Leopard, wild pig, common grey mongoose, and Indian hare showed cathemeral activity pattern. The present study serves as a baseline for future studies and help formulate conservation strategies for wild mammals in the study area.

Scanning sympatric sika deer and Japanese serows using drones: A methodological trial in Mt. Asama, Central Japan

AbstractThe negative impacts of sika deer (Cervus nippon) on Japanese serows (Capricornis crispus) are a subject of concern in the mountainous regions of Japan. To develop a methodology to collect information with regard to the abundance and habitat selection of sympatric large mammals using drones (unmanned aerial vehicles; UAVs) equipped with thermal infrared and red‐green‐blue (RGB) sensors, surveys were conducted at night and in the early morning in a high mountainous habitat. Despite the similar size and shape in thermal infrared images for sika deer and Japanese serows, species identification based on body color using RGB images was possible during the period from dawn to early morning. The UAV surveys also revealed the large abundance of deer (>40 deer/km2) and suggested different habitat selection between deer and serows in the alpine grassland. Our results were the first snapshots of sympathetic deer and serow distribution. UAV surveys using both thermal infrared and RGB sensors in early morning could be useful for research and monitoring of large mammals in open areas, such as grasslands, marshlands, high mountains, farmlands and drylands.

The most abundant mammals on Earth

New estimates of global mammal abundance that use relationships between traits, estimates of range size, and International Union for Conservation of Nature’s (IUCN’s) Red List categories to predict the biomass of thousands of species have been developed by Greenspoon et al. This approach and some of the challenges that contribute to these estimates are summarized here.

Inventory and abundance of non-volant mammals and birds in the unprotected regions of the Mount Apo Range, Philippines

Wildlife, such as non-volant mammals and birds, play a vital role in the maintenance of ecosystem health. They are considered ecological engineers that influence forest vegetation. However, due to deforestation, habitat loss, and human persecution, its population status has declined over the years. This study aimed to conduct a species inventory and assess the relative abundance of non-volant mammals and birds in the unprotected regions of the Mt. Apo Range, Philippines, through camera trapping methods. Furthermore, the anthropogenic threats observed in the study areas were also documented. A total of 1,106 camera trap days were carried out in 2016 and another 500 days in 2020. Based on 260 independent sequences for both the 2016 and 2020 surveys, 12 species were identified, consisting of eight non-volant mammals and four birds. Among the identified species are the Endangered Philippine Brown Deer Rusa marianna & Philippine Long-tailed Macaque Macaca fascicularis philippensis and the Vulnerable Giant Scops-owl Otus gurneyi & the Philippine Warty Pig Sus philippensis. Video evidence of the Philippine Warty Pig Sus philippensis performing an important ecological role as an ecological engineer in the Philippine tropical forests were also captured for the first time. Another 61 independent sequences of unidentified rodents were detected in the camera traps, requiring further species monitoring techniques. Conservation must be strengthened beyond the protected landscapes of the Mt. Apo Range through community-based forest governance. This will ensure that the forest vertebrates are protected and conserved from further anthropogenic pressures.

Abundance of larger mammals in Dinder National Park, Sudan

Abundance of larger mammals in Dinder National Park, Sudan

Composition, Relative Abundance, and Diversity of Medium and Large Mammals in Tirba Lake Awi Zone, Ethiopia

Understanding the diversity, abundance, and habitat preferences of the fauna is essential for determining the status and suggesting effective conservation actions. A study was conducted in Tirba Lake Awi zone, Ethiopia, to evaluate the wealth, diversity, and composition of the medium and large mammal communities. It is also important to consider how these parameters differ from one habitat type to another and from one season to another. Researchers collected data using a transect method. As a result of the study, 330 individuals and 11 different species of mammals were identified across four orders and six families. The result shows that globally threatened species like the Leopard (Panthera pardus) were included. In terms of seasonal variation in wild mammal abundance, the difference was statistically significant (P $$\le$$ 0.001). A total of 330 ± 26.2 wild mammals were recorded, of which 180 ± 11 (55%) were observed during the wet season and 150 ± 6.5 (45%) during the dry season. Olive Baboons (Papio Anubis) accounted for 30.61% of the 11 mammalian species with 101 individuals, followed by Vervet monkeys (Cercopithecus aethiops) with 16.67% and 55 individuals, respectively. Mammalian populations were statistically significant among habitat types, with the highest similarity index (SI = 0.8) observed between open forests and shrubland, followed by shrubland adjacent to Cliff sites (SI = 0.7). The shrubland habitat type (Hʹ = 1) supports the greatest diversity of mammalian species, followed by the open forest habitat type (Hʹ = 0.8). In terms of diversity among habitat types, dense forests had the lowest Hʹ value (0.5). Based on the species similarity index, open forest and shrubland shared the most similarity of mammalian species (Sl = 0.8), while shrubland and cliff sites hosted the least similar species (SI = 0.7). To conclude, our findings contribute significantly to the conservation of Ethiopia's mammal populations. As a result of our findings, managers of the area will be able to make effective conservation decisions, and researchers wishing to conduct related studies will be able to use the findings as a baseline for their research. Studies in the study area have revealed that anthropogenic factors interact with the mammals in the area, putting them at risk. It is imperative that these animals are protected through an urgent conservation program.

Habitat mosaic as a driver of the resilience of native species: The case of the assemblage of small mammals from the city of Franceville, Gabon

AbstractRodents (Rodentia) are the most abundant and diverse order of mammals, present in all habitats, including urban areas. The traffic linked to globalisation has favoured their involvement in biological invasions that have an impact on local biodiversity, the economy and human health. In Franceville, Gabon, little is known about the rodent community. We therefore studied the composition and distribution of rodents along a gradient highlighting the heterogeneity of the city's landscape. The three habitat types studied showed no difference in small mammal abundance, while the diversity index was higher in the vegetated habitat (SDI = 0.73) compared to the outdoor (SDI = 0.71) and indoor (SDI = 0.45) habitats. Our work shows the importance of vegetal remnants in the city for the maintenance of native species. It also highlights the impact of introduced species on small mammal assemblages and the need for management to reduce the factors of their proliferation.

Rodent-borne viruses in the region of Middle East.

Rodents are one of the most abundant mammal species in the world. They form more than two-fifth of all mammal species and there are approximately 4600 existing rodent species. Rodents are capable of transmitting deadly diseases, especially those that are caused by viruses. Viruses and their consequences have plagued the world for the last two centuries, three pandemics occurred during the last century only. The Middle East is situated at the crossroads of Africa and Asia, along with the Mediterranean Sea and the Indian Ocean, its geographic importance is gained through the diversity of topographies, biosphere, as well as climate aspects that make the region vulnerable to host emerging diseases. Refugee crises also play a major role in expected epidemic outbreaks in the region. Public health has always been the most important priority, and our aim in this review is to raise awareness among public health organisations across the Middle East about the dangers of rodent borne diseases that have been reported or are suspected to be found in the region.

Results and evaluation of US Navy shock trial environmental mitigation of marine mammals and sea turtles

A shock trial of a US Navy Destroyer, the USS Winston S. Churchill, was conducted offshore of northern Florida in May and June 2001. The shock trial consisted of three underwater detonation tests, spaced approximately one week apart. Environmental mitigation to minimise the impact of the shock trial on marine mammals and sea turtles was based on a Safety Range of 3.7km (2 n.miles) radius around the detonation site, and a Buffer Zone of an additional 1.85km (1 n.mile) radius beyond the Safety Range. Mitigation included site selection surveys, pre-detonation aerial, vessel and bio-acoustic monitoring, and post-detonation aerial and vessel monitoring. Six species of odontocete and two species of sea turtle were identified during mitigation monitoring, as well as several sightings that could not be identified by species. Site selection aerial surveys were implemented to select a test site with the lowest abundance of marine mammals and sea turtles. Nearly 300 animals were seen during site selection surveys. Pre-detonation aerial and vessel monitoring was implemented to sight any marine mammal and sea turtle within the Safety Range on designated test days, and track the animals until they could be verified to be outside the Safety Range. Approximately 1,200 marine mammals and 32 sea turtles were sighted during pre-detonation monitoring. Pre-detonation bio-acoustic monitoring was implemented to detect large cetaceans within the Safety Range and Buffer Zone; the only calls heard were from dolphins that could not be localised. Post-detonation monitoring was implemented to determine the effectiveness of mitigation procedures. No injured or dead marine mammals or turtles were detected during approximately 185 hours of post-detonation aerial and vessel visual monitoring. Post-detonation monitoring resulted in observations of 767 marine mammals and 42 sea turtles. With only two exceptions, the same marine mammal and sea turtle species were observed prior to, during and after the shock trial test time period. Factors leading to the success of this environmental mitigation effort are summarised, and recommendations for improvements to mitigation efforts of this size and scope are suggested. These recommendations include the use of a simultaneous second aircraft for improved coverage during pre-detonation surveys, increased post-detonation aerial monitoring, equitable survey data for all test sites under consideration during planning stages, and reassessment of bio-acoustic monitoring need and purpose.