Variation In Body Mass Research Articles

Human Disturbance during Early Life Impairs Nestling Growth in Birds Inhabiting a Nature Recreation Area

Nature recreation conflicts with conservation, but its impacts on wildlife are not fully understood. Where recreation is not regulated, visitors to natural areas may gather in large numbers on weekends and holidays. This may increase variance in fitness in wild populations, if individuals whose critical life cycle stages coincide with periods of high human disturbance are at a disadvantage. We studied nestling development of blue tits (Cyanistes caeruleus) in a natural area where recreation activities intensify during weekends and other public holidays at picnic and leisure facilities, but not in the surrounding woods. In nests located near recreation facilities, blue tit nestlings that hatched during holidays developed slowly, and fledged with low body mass and poor body condition. However, nestlings that hatched outside of holidays and weekends in these nest boxes developed normally, eventually attaining similar phenotypes as those hatching in the surrounding woods. Within-brood variance in body mass was also higher in broods that began growing during holidays in disturbed areas. Our results show that early disturbance events may have negative consequences for wild birds if they overlap with critical stages of development, unveiling otherwise cryptic impacts of human activities. These new findings may help managers better regulate nature recreation.

Mechatronic suspension design for full rail vehicle system

In this paper, an analytical mechatronic dynamic design model of a full rail vehicle system is developed. Based on the rail vehicle motion, its degree of freedom can be reduced to only 38. This reduction is necessary for the model simplicity. The developed model is validated with experimental result and compared with other one from literature. The real characteristics of the actuators are discussed, and its controller is designed. A mechatronic model that expresses the controlled tracking error as function of the vehicle dynamics and the actuator characteristics is developed. This model is used by the linear quadratic regulator approach to identify the mechatronic rail vehicle proportional–integral–derivative controller’s gains. The mechatronic rail vehicle comfort is evaluated in terms of the passenger displacement, acceleration and frequency as a response of a rail irregularities caused by a lateral and two vertical track irregularities. The simulations of vibration analysis are obtained in time and frequency domains and compared with railway vehicle status. The robustness of the designed mechatronic rail vehicle is verified by simulations, carried out for the cases of car body mass variations. The results show the effectiveness of the proposed mechatronic rail vehicle design which improves significantly the transportation of passengers.

Dung beetle community dynamics in undisturbed tropical forests: implications for ecological evaluations of land‐use change

Abstract The impacts of human activities on tropical forests are widespread and increasing. Hence, a good knowledge base about ecological processes in undisturbed tropical forest is crucial to provide a baseline for evaluating anthropogenic change. Our 5‐year study focused on understanding the background spatial and inter‐annual variation in dung beetle communities at 12 sites of undisturbed lowland tropical rainforest in the Brazilian Amazon. We then assessed how this variation may affect ecological evaluations of anthropogenic influence by comparing community metrics with comparable dung beetle data collected from 15 sites of Eucalyptus plantation in the same region. Of all measured environmental variables, soil texture best explained spatial variation in dung beetle communities in undisturbed forests. Furthermore, soil texture was important for community assembly as it was associated with dung beetle nesting behaviours. While the relative abundance of dung beetle functional groups was stable over time, there were important inter‐annual temporal dynamics, with a fivefold variation in abundance and body mass, and with species richness ranging from 52 to 74. These temporal oscillations were probably caused by variation in dry season rainfall. This inter‐annual variation influenced the comparison between undisturbed forests and plantations, which could lead to inconsistencies in evaluation of anthropogenic change. We therefore highlight the importance of understanding natural variation in studies evaluating the consequences of land‐use change and other forest disturbances on forest biodiversity.

UV radiation impacts body weight, oxygen consumption, and shelter selection in the intertidal vertebrate Girella laevifrons

The amount of ultraviolet (UV) radiation reaching the earth's surface has increased due to ozone layer depletion, and this fact represents an opportunity to evaluate the physiological and behavioral responses of animals to this global-scale stressor. The transitory fish Girella laevifrons inhabits pools in the upper intertidal zone, which is characterized by exposure to a wide range of stressors, including UV radiation. We documented the field magnitude and the impact of UV radiation on oxygen consumption, body mass variations, and shelter (rocky and algae) selection by G. laevifrons. UV-exposed animals showed increased oxygen consumption, slower body weight increase, and active rocky shelter selection. Control fish showed increased body weight and no evident shelter selection. The results indicated that UV exposure affects fish energetic balance and habitat selection to favor greater protection against radiation. Increased UV exposure in transitory intertidal animals at levels observed in upper intertidal pools may alter the residency time of fish before leaving for the subtidal zone. Therefore, UV-induced energetic changes may determine animal performance and ontogenetic physiological itineraries, whereas shelter quality might determine habitat use.

Carvacrol reduces irinotecan-induced intestinal mucositis through inhibition of inflammation and oxidative damage via TRPA1 receptor activation

Intestinal mucositis is an inflammatory process occurring in the intestinal mucosa and is a common side effect of irinotecan hydrochloride (CPT-11) based anticancer regimens. The transient receptor potential cation channel, subfamily A, member 1 (TRPA1) receptor is highly expressed in the intestinal mucosa and has the ability to identify cell damage signaling indicates its possible association with intestinal mucositis. Carvacrol is an agonist of the TRPA1 receptor and has anti-inflammatory properties. Thus, the aim of the present study was to verify the supposed anti-inflammatory and protective action of carvacrol via TRPA1 activation against intestinal mucositis induced by CPT-11 in mice. Briefly, mice were treated with either DMSO 2% or CPT-11 (75 mg/kg, per 4 days, i.p.) or the carvacrol (25, 75 or 150 mg/kg, per 8 days, i.p.) before CPT-11. In other group, the animals were pretreated with HC-030031, a TRPA1 antagonist, 30 min before treatment with carvacrol. On day 7, animal survival and bacteremia were assessed, and following euthanasia, samples of the jejunum were obtained for morphometric analysis and measurement of antioxidant and pro-inflammatory markers. Carvacrol was found to exert an anti-inflammatory action against CPT-11-induced intestinal mucositis through strong interactions with TRPA1 receptors; reduction in the production or release or both of pro-inflammatory cytokines (TNF-α, IL-1β, and KC); and decrease in other indicators of inflammation (MPO, NF-κB, COX-2) and oxidative stress (GSH, MDA, and NOx levels). It also contributed to the restoration of the tissue architecture of the villi and crypts in the small intestine, and improved clinical parameters such as survival, body mass variation, leukogram, and blood bacterial count. Thus, TRPA1 could be a target for future therapeutic approaches in the treatment of intestinal mucositis.

Cohort variation in individual body mass dissipates with age in large herbivores

AbstractEnvironmental conditions experienced during early growth and development markedly shape phenotypic traits. Consequently, individuals of the same cohort may show similar life‐history tactics throughout life. Conditions experienced later in life, however, could fine‐tune these initial differences, either increasing (cumulative effect) or decreasing (compensatory effect) the magnitude of cohort variation with increasing age. Our novel comparative analysis that quantifies cohort variation in individual body size trajectories shows that initial cohort variation dissipates throughout life, and that lifetime patterns change both across species with different paces of life and between sexes. We used longitudinal data on body size (mostly assessed using mass) from 11 populations of large herbivores spread along the “slow‐fast” continuum of life histories. We first quantified cohort variation using mixture models to identify clusters of cohorts with similar initial size. We identified clear cohort clusters in all species except the one with the slowest pace of life, revealing that variation in early size is structured among cohorts and highlighting typological differences among cohorts. Growth trajectories differed among cohort clusters, highlighting how early size is a fundamental determinant of lifetime growth patterns. In all species, among‐cohort variation in size peaked at the start of life, then quickly decreased with age and stabilized around mid‐life. Cohort variation was lower in species with a slower than a faster pace of life, and vanished at prime age in species with the slowest pace of life. After accounting for viability selection, compensatory/catch‐up growth in early life explained much of the decrease in cohort variation. Females showed less phenotypic variability and stronger compensatory/catch‐up growth than males early in life, whereas males showed more progressive changes throughout life. These results confirm that stronger selective pressures for rapid growth make males more vulnerable to poor environmental conditions early in life and less able to recover after a poor start. Our comparative analysis illustrates how variability in growth changes over time in closely related species that span a wide range on the slow‐fast continuum, the main axis of variation in life‐history strategies of vertebrates.

Specific BIVA recognizes variation of body mass and body composition: Two related but different facets of nutritional status

ObjectiveThe aim of this study was to demonstrate the different information provided by body mass index (BMI) in combination with specific bioelectrical impedance vector analysis (specific BIVA) in the measure of relative body fat. MethodsAnthropometric and bioelectrical values and dual-energy x-ray absorpitometry measurements from a sample of 1590 US adults of both sexes were retrieved from the National Health and Nutrition Examination Survey 2003–2004. The sample distribution of the BMI of each sex was divided into deciles. Quartiles were calculated for percent fat mass (FM%) after stratifying by BMI deciles. Body composition and bioelectrical characteristics of groups below the first and above the third quartile were compared using analysis of variance and the Hotelling's T-square test. ResultsBMI and specific BIVA showed a different accuracy in detecting body composition variations: BMI showed similar values in groups represented by different FM percentages, whereas the bioelectrical differences were statistically significant. The mean impedance vectors corresponding to cases below the first FM% quartiles were shorter and located on the left side of the ellipses (the region of higher fat-free mass), whereas those above the third FM% quartiles were on the right and toward the upper pole (the region of higher FM%). ConclusionsSpecific BIVA is a technique for the evaluation of body composition which can add relevant information regarding BMI.

Sex-specific patterns in body mass and mating system in the Siberian flying squirrel

Reproductive strategies and evolutionary pressures differ between males and females. This often results in size differences between the sexes, and also in sex-specific seasonal variation in body mass. Seasonal variation in body mass is also affected by other factors, such as weather. Studies on sex-specific body mass patterns may contribute to better understand the mating system of a species. Here we quantify patterns underlying sex-specific body mass variation using a long-term dataset on body mass in the Siberian flying squirrel, Pteromys volans. We show that female flying squirrels were larger than males based on body mass and other body measures. Males had lowest body mass after the breeding season, whereas female body mass was more constant between seasons, when the pregnancy period was excluded. Male body mass did not increase before the mating season, despite the general pattern that males with higher body mass are usually dominant in squirrel species. Seasonal body mass variation was linked to weather factors, but this relationship was not straightforward to interpret, and did not clearly affect the trend in body mass observed over the 22 years of study. Our study supports the view that arboreal squirrels often deviate from the general pattern found in mammals for larger males than females. The mating system seems to be the main driver of sex-specific seasonal body mass variation in flying squirrels, and conflicting selective pressure may occur for males to have low body mass to facilitate gliding versus high body mass to facilitate dominance.

Being fat and smart: A comparative analysis of the fat-brain trade-off in mammals

Humans stand out among non-aquatic mammals by having both an extremely large brain and a relatively large amount of body fat. To understand the evolution of this human peculiarity we report a phylogenetic comparative study of 120 mammalian species, including 30 primates, using seasonal variation in adult body mass as a proxy of the tendency to store fat. Species that rely on storing fat to survive lean periods are expected to be less active because of higher costs of locomotion and have increased predation risk due to reduced agility. Because a fat-storage strategy reduces the net cognitive benefit of a large brain without reducing its cost, such species should be less likely to evolve a larger brain than non-fat-storing species. We therefore predict that the two strategies to buffer food shortages (storing body fat and cognitive flexibility) are compensatory, and therefore predict negative co-evolution between relative brain size and seasonal variation in body mass. This trade-off is expected to be stronger in predominantly arboreal species than in more terrestrial ones, as the cost of transporting additional adipose depots is higher for climbing than for horizontal locomotion. We did, indeed, find a significant negative correlation between brain size and coefficient of variation (CV) in body mass in both sexes for the subsample of arboreal species, both in all mammals and within primates. In predominantly terrestrial species, in contrast, this correlation was not significant. We therefore suggest that the adoption of habitually terrestrial locomotor habits, accompanied by a reduced reliance on climbing, has allowed for a primate of our body size the unique human combination of unusually large brains and unusually large adipose depots.

Both natural selection and isolation by distance explain phenotypic divergence in bill size and body mass between South Australian little penguin colonies.

Morphological variation between populations of the same species can arise as a response to genetic variation, local environmental conditions, or a combination of both. In this study, I examined small‐scale geographic variation in bill size and body mass in little penguins (Eudyptula minor) across five breeding colonies in South Australia separated by <150 km. To help understand patterns driving the differences, I investigated these variations in relation to environmental parameters (air temperature, sea surface temperature, and water depth) and geographic distances between the colonies. I found substantial morphological variation among the colonies for body mass and bill measurements (except bill length). Colonies further located from each other showed greater morphological divergence overall than adjacent colonies. In addition, phenotypic traits were somewhat correlated to environmental parameters. Birds at colonies surrounded by hotter sea surface temperatures were heavier with longer and larger bills. Birds with larger and longer bills were also found at colonies surrounded by shallower waters. Overall, the results suggest that both environmental factors (natural selection) and interpopulation distances (isolation by distance) are causes of phenotypic differentiation between South Australian little penguin colonies.

Morphoquantitative effects on striated skeletal muscle of Wistar rats (Rattus norvegicus) subjected to a diet utilized in young children from rural Mozambique

Mozambique is a country of sub-Saharan Africa where about 55% of the population lives below the absolute poverty line with less than one meal a day hardly surviving based on by donations. Food insecurity and precarious nutrition, especially in children, are factors that induce to levels of 44% of chronic malnutrition (CD) in infants. The CD is responsible for one third of deaths in children under five years. The aim of this study was to evaluate the morphoquantitative effects in gastrocnemius muscle of Wistar rats fed with a diet utilized by people from rural areas of Mozambique. We used 75 Wistar rats weighing approximately 300 g divided in three groups: nourished or control (N), malnourished (D), and Mozambique or experimental group (M), measured at birth and at weaning. The animals were kept under the same housing conditions, temperature, humidity and light, but with different diets depending on the group: Group N with normal protein diet (20% casein), Group D with hypo-proteic diet (5% casein), and Group M with Mozambique diet. In all groups we evaluated the body mass at birth and weaning, and collected the right gastrocnemius muscle of male pups at weaning for analysis. Serial sections of 10 μm were performed in a cryostat prior to histology techniques of hematoxylin and eosin, picrosirius, NADH-tr and analysis in transmission electron microscope. Statistical evaluation was determined by analysis of variance (ANOVA) and Tukey tests. Significant differences were found between groups N, D and M. In group M were observed a great variation of body mass that was approximately similar to group D; Group M also showed the same changes in muscle fiber which exhibited round-shaped contours, and predominance of type III collagen, similarly to malnourished group (D). Ultra-structurally, animals from Mozambique displayed a disorganization of the Z lines of sarcomeres, myofibrils disruption, decreased cross-sectional area and a smaller proportion of glycolytic and glycolytic-oxidative fibers. Additionally, the animals from M group revealed higher percentage and cross-sectional area identical to group D in respect to oxidative fibers.

The domesticated brain: genetics of brain mass and brain structure in an avian species.

As brain size usually increases with body size it has been assumed that the two are tightly constrained and evolutionary studies have therefore often been based on relative brain size (i.e. brain size proportional to body size) rather than absolute brain size. The process of domestication offers an excellent opportunity to disentangle the linkage between body and brain mass due to the extreme selection for increased body mass that has occurred. By breeding an intercross between domestic chicken and their wild progenitor, we address this relationship by simultaneously mapping the genes that control inter-population variation in brain mass and body mass. Loci controlling variation in brain mass and body mass have separate genetic architectures and are therefore not directly constrained. Genetic mapping of brain regions indicates that domestication has led to a larger body mass and to a lesser extent a larger absolute brain mass in chickens, mainly due to enlargement of the cerebellum. Domestication has traditionally been linked to brain mass regression, based on measurements of relative brain mass, which confounds the large body mass augmentation due to domestication. Our results refute this concept in the chicken.

Contrasting effects of summer and winter warming on body mass explain population dynamics in a food-limited Arctic herbivore.

The cumulative effects of climate warming on herbivore vital rates and population dynamics are hard to predict, given that the expected effects differ between seasons. In the Arctic, warmer summers enhance plant growth which should lead to heavier and more fertile individuals in the autumn. Conversely, warm spells in winter with rainfall (rain-on-snow) can cause 'icing', restricting access to forage, resulting in starvation, lower survival and fecundity. As body condition is a 'barometer' of energy demands relative to energy intake, we explored the causes and consequences of variation in body mass of wild female Svalbard reindeer (Rangifer tarandus platyrhynchus) from 1994 to 2015, a period of marked climate warming. Late winter (April) body mass explained 88% of the between-year variation in population growth rate, because it strongly influenced reproductive loss, and hence subsequent fecundity (92%), as well as survival (94%) and recruitment (93%). Autumn (October) body mass affected ovulation rates but did not affect fecundity. April body mass showed no long-term trend (coefficient of variation, CV=8.8%) and was higher following warm autumn (October) weather, reflecting delays in winter onset, but most strongly, and negatively, related to 'rain-on-snow' events. October body mass (CV=2.5%) increased over the study due to higher plant productivity in the increasingly warm summers. Density-dependent mass change suggested competition for resources in both winter and summer but was less pronounced in recent years, despite an increasing population size. While continued climate warming is expected to increase the carrying capacity of the high Arctic tundra, it is also likely to cause more frequent icing events. Our analyses suggest that these contrasting effects may cause larger seasonal fluctuations in body mass and vital rates. Overall our findings provide an important 'missing' mechanistic link in the current understanding of the population biology of a keystone species in a rapidly warming Arctic.

Female fecundity traits in wild populations of African annual fish: the role of the aridity gradient.

The evolution of life history is shaped by life expectancy. Life‐history traits coevolve, and optimal states for particular traits are constrained by trade‐offs with other life‐history traits. Life histories contrast among species, but may also diverge intraspecifically, at the level of populations. We studied the evolution of female reproductive allocation strategy, using natural populations of two sympatric species of African annual fishes, Nothobranchius furzeri and Nothobranchius orthonotus. These species inhabit pools in the Mozambican savanna that are formed in the rainy season and persist for only 2–10 months. Using 207 female N. furzeri from 11 populations and 243 female N. orthonotus from 14 populations, we tested the effects of genetic background (intraspecific lineage) and life expectancy (position on the aridity gradient determining maximum duration of their temporary habitat) on female fecundity traits. First, we found that variation in female body mass was small within populations, but varied considerably among populations. Second, we found that fecundity was largely defined by female body mass and that females spawned most of their eggs in the morning. Third, we found that the trade‐off between egg size and egg number varied among lineages of N. furzeri and this outcome has been confirmed by data from two separate years. Overall, we demonstrate that local conditions were important determinants for Nothobranchius growth and fecundity and that eggs size in arid region was less limited by female fecundity than in humid region.

Heat resistance throughout ontogeny: body size constrains thermal tolerance.

Heat tolerance is a trait of paramount ecological importance and may determine a species' ability to cope with ongoing climate change. Although critical thermal limits have consequently received substantial attention in recent years, their potential variation throughout ontogeny remained largely neglected. We investigate whether such neglect may bias conclusions regarding a species' sensitivity to climate change. Using a tropical butterfly, we found that developmental stages clearly differed in heat tolerance. It was highest in pupae followed by larvae, adults and finally eggs and hatchlings. Strikingly, most of the variation found in thermal tolerance was explained by differences in body mass, which may thus impose a severe constraint on adaptive variation in stress tolerance. Furthermore, temperature acclimation was beneficial by increasing heat knock-down time and therefore immediate survival under heat stress, but it affected reproduction negatively. Extreme temperatures strongly reduced survival and subsequent reproductive success even in our highly plastic model organism, exemplifying the potentially dramatic impact of extreme weather events on biodiversity. We argue that predictions regarding a species' fate under changing environmental conditions should consider variation in thermal tolerance throughout ontogeny, variation in body mass and acclimation responses as important predictors of stress tolerance.

Seasonal variations of sexual size dimorphism in two Mediterranean bat species from Tunisia: the Kuhl's pipistrelle (Pipistrellus kuhlii) and the Isabelline serotine (Eptesicus isabellinus)

Body mass variations of Pipistrellus kuhlii and Eptesicus isabellinus were studied in the Bou Hedma National Park (central Tunisia) from June 2010 to June 2011. In both species, adult females were significantly heavier than males throughout the year. Seasonal variations were larger in adult females, body mass peaking during late pregnancy. After a secondary peak in September–October observed in both sexes in E. isabellinus, in males only in P. kuhlii, body mass reached a minimum value in winter when activity is low. Significant differences were also noticed between years in June for both species. Such pattern of seasonal variations of sexual size dimorphism is typical of hibernating vespertilionids.

Anti-inflammatory and Anti-resorptive Effects of Atorvastatin on Alveolar Bone Loss in Wistar Rats.

The aim of this study was to evaluate the anti-inflammatory and anti-resorptive effect of atorvastatin (ATV) in an experimental alveolar bone loss (ABL) model. Wistar rats were subjected to ligature placement around the maxillary second molar for 11 days. The animals received 0.9% saline (2 mL/kg) or ATV (0.3, 3 or 27 mg/kg) daily by gavage. ABL was evaluated by resorption area and histopathological analysis. Serum bone-specific alkaline phosphatase (BALP) activity was also evaluated. Leukogram was performed at 0 h, 6th h, 2nd, 7th and 11th days. Kidney and liver conditions and the body mass variation were analyzed. ATV (3 and 27 mg/kg) inhibited ABL by 39% and 56%, respectively. Histopathological analysis showed that ATV 27 mg/kg prevented ABL and cemental resorption, and inflammatory cell infiltration induced by ligature. ATV (27 mg/kg) prevented serum BALP levels reduction. ATV (27 mg/kg) prevented leukocytosis and did not affect either kidney or liver function nor body mass weight. ATV showed a protecting effect in the ligature-induced periodontitis, without affecting system parameters, by inhibition of inflammatory process and by its anabolic activity on the alveolar bone.

Dry Extract of Matricaria recutita L. (Chamomile) Prevents Ligature-Induced Alveolar Bone Resorption in Rats via Inhibition of Tumor Necrosis Factor-α and Interleukin-1β.

Matricaria recutita L. (chamomile) has demonstrated anti-inflammatory activity. Accordingly, the ability of the Matricaria recutita extract (MRE) to inhibit proinflammatory cytokines and its influence on alveolar bone resorption (ABR) in rats. Wistar rats were subjected to ABR by ligature with nylon thread in the second upper-left molar, with contralateral hemiarcade as control. Rats received polysorbate TW80 (vehicle) or MRE (10, 30, and 90 mg/kg) 1 hour before ligature and daily until day 11. The periodontium was analyzed by macroscopy, histometry, histopathology, and immunohistochemistry for the receptor activator of nuclear factor-kappa B ligand (RANKL), osteoprotegerin (OPG), and tartrate-resistant acid phosphatase (TRAP). The gingival tissue was used to quantify the myeloperoxidase (MPO) activity and tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels by enzyme-linked immunosorbent assay. Blood samples were collected to evaluate bone-specific alkaline phosphatase (BALP), leukogram, and dosages of aspartate and alanine transaminases, urea, and creatinine. Aspects of liver, kidneys, spleen, and body mass variations were also evaluated. The 11 days of ligature induced bone resorption, low levels of BALP, leukocyte infiltration; increase of MPO, TNF-α, and IL-1β; immunostaining increase for RANKL and TRAP; reduction of OPG and leukocytosis, which were significantly prevented by MRE, except for the low levels of BALP and the leukocytosis. Additionally, MRE did not alter organs or body weights of rats. MRE prevented the inflammation and ABR by reducing TNF-α and IL-1β, preventing the osteoclast activation via the RANKL-OPG axis, without interfering with bone anabolism.

Does Water Temperature Affect the Timing and Duration of Remigial Moult in Sea Ducks? An Experimental Approach.

Aquatic birds have high cost of thermoregulation, especially during the moulting period, yet the effect of water temperature on the moulting strategy of aquatic birds has rarely been studied. Our general hypothesis is that energy savings associated with lower thermoregulation costs would be allocated to moulting processes. We predicted that aquatic birds moulting in warm water would have a higher level of body reserves, a faster growth rate of feathers, and an earlier remigial moult onset compared with birds moulting in cold water. We used the common eider (Somateria mollissima dresseri), a large sea duck, as the model species. Captive individuals were experimentally exposed to warm (18°C) and cold (8°C) water treatments during a three year period with individuals swapped between treatments. We found a similar feather growth rate for the two water temperature treatments and in contrast to our predictions, eiders exposed to warm water had a lower body mass and showed a delayed onset of remigial moult of approximately 7 days compared with those exposed to cold water. Our data indicate that body mass variations influence the timing of moult in unexpected ways and we suggest that it likely controls the occurrence of wing moult through a hormonal cascade. This study emphasizes the importance of improving our knowledge of the effects of water temperature on remigial moult of aquatic birds, to better assert the potential effects of global warming on their survival.

Spatio-temporal variation in small mammal species richness, relative abundance and body mass reveal changes in a coastal wetland ecosystem in Ghana.

Coastal wetlands in Ghana are under severe threat of anthropogenic drivers of habitat degradation and climate change, thereby increasing the need for assessment and monitoring to inform targeted and effective conservation of these ecosystems. Here, we assess small mammal species richness, relative abundance and body mass in three habitats at the Muni-Pomadze Ramsar site of Ghana, and compare these to baseline data gathered in 1997 to evaluate changes in the wetland ecosystem. Small mammals were live-trapped using Sherman collapsible and pitfall traps. We recorded 84 individuals of 10 species in 1485 trap-nights, whereas the baseline study recorded 45 individuals of seven species in 986 trap-nights. The overall trap-success was therefore greater in the present study (5.66%) than the baseline study (4.56%). The species richness increased from one to four in the forest, and from zero to eight in the thicket, but decreased from six to four in the grassland. The total number of individuals increased in all habitats, with the dominant species in the grassland shifting from Lemniscomys striatus to Mastomys erythroleucus. Three species, Malacomys edwardsi, Grammomys poensis and Praomys tullbergi are the first records for the Muni-Pomadze Ramsar site. Generally, the average body mass of individual species in the grassland was lower in the present study. The considerable changes in small mammal community structure suggest changes in the wetland ecosystem. The conservation implications of our findings are discussed.