Seasonal habitat use by Elephants (Loxodonta africana) in the Mole National Park of Ghana

To avoid unnecessary waste of limited resources and to help prioritize areas for conservation efforts, this study aimed to provide information on habitat use by elephants between the wet and dry seasons in the Mole National Park (MNP) of Ghana. We compiled coordinates of 516 locations of elephants’ encounters, 256 for dry season and 260 for wet season. Using nine predictor variables, we modeled the probability of elephant's distribution in MNP. We threshold the models to “suitable” and “nonsuitable” regions of habitat use using the equal training sensitivity and specificity values of 0.177 and 0.181 for the dry and wet seasons, respectively. Accuracy assessment of our models revealed a sensitivity score of 0.909 and 0.974, and a specificity of 0.579 and 0.753 for the dry and wet seasons, respectively. A TSS of 0.488 was also recorded for the dry season and 0.727 for the wet season indicating a good model agreement. Our model predicts habitat use to be confined to the southern portion of MNP due to elevation difference and a relatively steep slope that separates the northern regions of the park from the south. Regions of habitat use for the wet season were 856 km² and reduced significantly to 547.68 km² in the dry season. We observed significant overlap (327.24 km²) in habitat use regions between the wet and dry seasons (Schoener's D = 0.922 and Hellinger's‐based I = 0.991). DEM, proximity to waterholes, and saltlicks were identified as the key variables that contributed to the prediction. We recommend construction of temporal camps in regions of habitat use that are far from the headquarters area for effective management of elephants. Also, an increase in water point's density around the headquarters areas and selected dry areas of the park will further decrease elephant's range and hence a relatively less resource use in monitoring and patrols.     

A survey of gastrointestinal parasites of olive baboons (Papio anubis) in human settlement areas of Mole National Park, Ghana

Fecal samples from 55 free-ranging olive baboons (Papio anubis) in Mole National Park, Ghana, were collected 22 June-7 July 2008 and analyzed for gastrointestinal parasites. This is the first survey of baboon gastrointestinal parasites in Ghana and provides baseline data for this area. Ninety-three percent of samples were infected, leaving 7% with no parasites observed. Of those infected, there was a 76% prevalence of strongyles, 53% Strongyloides spp., 11% Abbreviata caucasica , 62% prevalence of Balantidium coli (trophozoites and cysts identified), 4% Entomeba hystolytica/dispar, and 47% unidentified protozoan parasites. Of the strongyle infections, 9% were identified as Oesophagostamum sp. One sample contained an unidentified spirurid nematode that resembled Gongylonema sp. Mole has a mixed forest-savanna habitat, and baboons frequently range into human areas, which makes them subject to parasites from each habitat and multiple sources of exposure. We found a high prevalence of nematode parasites, consistent with a wet or cooler forest environment, or high rates of fecal contamination. The presence of Strongyloides sp., E. hystolitica/dispar, and B. coli suggest potential public health risk from baboons, but molecular identification of these parasites, and documentation of their presence in local human populations, would be necessary to confirm zoonotic transmission.     

The importance of unmanaged coastal wetlands to waterbirds at coastal Ghana

Ghana's 550 km coastline has about 100 wetlands out of which five large ones are managed as Ramsar sites, the rest being unmanaged. Recent pollution and misuse of unmanaged wetlands have necessitated a study into their roles in the support of waterbirds. Waterbird survey on four wetlands between September 2005 and April 2006 revealed that 51 waterbird species make use of the managed compared to 44 in the unmanaged wetlands. Average numbers of waterbirds were higher on the managed wetlands (10,510 ± 4862) than on the unmanaged wetlands (1348 ± 602) (P < 0.05) but mean population density of waterbirds (n/ha) was the same for both the managed (1860 ± 310) and unmanaged (1400 ± 220) (P > 0.05) wetlands. The population densities of waterbirds belonging to guilds 1, 5 and 7 were significantly higher on the managed wetlands (P < 0.05). In contrast, guilds 2 and 4 have significantly higher population densities on the unmanaged wetlands while the population density of guild 3 was the same (P > 0.05). There was an indication that during mid and late periods of the nonbreeding season, the unmanaged wetlands altogether may support a larger number of waterbirds belonging to guilds 2, 3 and 4 than the five managed wetlands.     

Landscape approaches to studying the effects of disturbance on waterbirds

The internationally important populations of waterbirds that winter in the United Kingdom can face intense pressure from human disturbance as a result of the high urbanization found around many protected coastal or inland wetland sites. Here, I describe and evaluate an approach that has been used to investigate the spatial effects of human disturbance on waterbirds. Rather than directly investigating behavioural responses to individual disturbance events, the presence of features in the landscape associated with disturbance is instead used as a surrogate, with the essential aim being to demonstrate that bird numbers or densities are depressed or their behaviour altered in proximity to areas used by humans. This paper first describes case studies that demonstrate the limitations of the basic inference (i.e. that disturbance influences patterns of waterbird distribution or behaviour) and then how investigations might be strengthened. For conclusions to be sound, it is particularly important that other factors, such as food supply, that might also explain the spatial patterns observed are considered or other corroborative evidence presented. The approach is thus least applicable in the most heterogeneous environments where many factors, perhaps spatially autocorrelated, may explain variation in distribution or behaviour. However, greatest confidence in the validity of conclusions may be gained where studies are able to show (ideally by experimental manipulation) that species' distributions or behaviour vary temporally in line with the levels of human use of the features examined. Although its aim and scope are thus limited, the use of a landscape approach, provided that it takes into account other factors affecting spatial variation in bird abundance or behaviour, can provide a preliminary assessment of species avoidance of key sources of disturbance that may offer a framework for more detailed investigation.     

Vegetation and disturbance history of the Bavarian Forest National Park,Germany

Vegetation History and Archaeobotany - National parks are supposed to protect large-scale ecological processes, along with species and ecosystems. Detailed knowledge about past vegetation and...     

Grasshopper biodiversity and bioindicators in Australian tropical savannas: Responses to disturbance in Kakadu National Park

Grasshoppers are a dominant group of herbivorous insects throughout the world, and their high diversity, functional importance, sensitivity to disturbance and ease of sampling makes them potentially useful bioindicators for land management. In Australia, however, the dynamics of grasshopper assemblages are extremely poorly understood. Here we describe the responses of grasshopper (Acridoidea, Eumastacoidea and Tettigonioidea) assemblages in the Kakadu region of the Northern Territory, Australia to disturbance associated with mining. Three questions were addressed in this study: (i) do local grasshopper assemblages show consistent responses to disturbance?; (ii) can particular species or functional groups be identified that are reliable indicators of ecological disturbance?; and (iii) to what extent do the responses of grasshopper assemblages merely reflect those of vegetation? Grasshoppers were sampled at 26 sites located in and around the Ranger uranium mine, representing three habitat types with respect to degree of disturbance: (i) ‘natural’ (10 sites representing a range of ‘undisturbed’ savanna habitats); (ii) ‘disturbed’ (10 sites representing a range of disturbances, but with soil intact); and (iii) ‘waste rock’ (six sites undergoing rehabilitation on a constructed landform). A total of 56 grasshopper species in 46 genera was recorded during the study, with site species richness ranging from five to 20. There were no significant differences between habitat types in site species diversity, but multivariate analysis demonstrated a strong correspondence between grasshopper species composition and degree of habitat disturbance. Using Indicator Species Analysis, six species and one functional group were identified as significant indicators of habitat type in relation to disturbance. Grasshopper responses were correlated with that of vegetation, but grasshopper assemblages showed apparently meaningful differentiation among disturbed sites that was not evident on the basis of floristic data. Our results demonstrate that grasshopper assemblages respond to disturbances associated with human land use and that these responses do not simply reflect those of plants. Grasshoppers are therefore potentially useful bioindicators of ecological disturbance in Australia, but further work is required on the extent to which their responses reflect general ecological change.     

Estimating population sizes for elusive animals: the forest elephants of Kakum National Park,Ghana

African forest elephants are difficult to observe in the dense vegetation, and previous studies have relied upon indirect methods to estimate population sizes. Using multilocus genotyping of noninvasively collected samples, we performed a genetic survey of the forest elephant population at Kakum National Park, Ghana. We estimated population size, sex ratio and genetic variability from our data, then combined this information with field observations to divide the population into age groups. Our population size estimate was very close to that obtained using dung counts, the most commonly used indirect method of estimating the population sizes of forest elephant populations. As their habitat is fragmented by expanding human populations, management will be increasingly important to the persistence of forest elephant populations. The data that can be obtained from noninvasively collected samples will help managers plan for the conservation of this keystone species.     

An evaluation of the concept of living at moderate altitude and training at sea level

Despite equivocal findings about the benefit of altitude training, current theory dictates that the best approach is to spend several weeks living at > or =2500 m but training near sea level. This paper summarizes six studies in which we used simulated altitude (normobaric hypoxia) to examine: (i) the assumption that moderate hypoxia compromises training intensity (two studies); and (ii) the nature of physiological adaptations to sleeping in moderate hypoxia (four studies). When submaximal exercise was >55% of sea level maximum oxygen uptake (VO2max), 1800 m simulated altitude significantly increased heart rate, blood lactate and perceived exertion of skiers. In addition, cyclists self-selected lower workloads during high-intensity exercise in hypoxia (2100 m) than in normoxia. Consequently, our findings partially confirm the rationale for 'living high, training low'. In the remaining four studies, serum erythropoietin increased 80% in the early stages of hypoxic exposure, but the reticulocyte response did not significantly exceed that of control subjects. There was no significant increase in haemoglobin mass (Hb(mass)) and VO2max tended to decrease. Performance in exercise tasks lasting approximately 4 min showed a non-significant trend toward improvement (1.0+/-0.4% vs. 0.1+/-0.4% for a control group; P=0.13 for group x time interaction). We conclude that sleeping in moderate hypoxia (2650-3000 m) for up to 23 days may offer practical benefit to elite athletes, but that any effect is not likely due to increased Hb(mass) or VO2max.     

Deaths from exertional myopathy at the National Zoological Park from 1975 to 1985

A retrospective study was conducted to determine the incidence of deaths from exertional myopathy (EM) in the hoofstock collection at the National Zoological Park (NZP) from 1975 to 1985. The diagnosis of EM was based on history, clinical signs, clinicopathological findings, gross and microscopic lesions. Only bovids, cervids, and equids were included in the study. Data were derived from the medical and pathological records of the NZP. There were 10 cases of EM during this period, but only seven deaths were directly attributable to EM. Five deaths occurred after immobilization. Two deaths occurred after improper transport, but the anesthetic history was not known in these cases. Pathologic changes consistent with EM were incidental findings in an animal killed by dogs, and in two animals euthanized because of suspected infection with Parelaphostrongylus tenuis. Only cervids and bovids were affected. There was no age or sex predilection for developing EM and deaths occurred throughout the year. Deaths associated with immobilization occurred most often after anesthesia with xylazine and etorphine. These are the drugs used most frequently in bovid and cervid anesthesia at the NZP. The overall incidence of deaths from EM after immobilization was 0.25% for the 10-yr period.     

Genetic population substructure in bison at Yellowstone National Park

The Yellowstone National Park bison herd is 1 of only 2 populations known to have continually persisted on their current landscape since pre-Columbian times. Over the last century, the census size of this herd has fluctuated from around 100 individuals to over 3000 animals. Previous studies involving radiotelemetry, tooth wear, and parturition timing provide evidence of at least 2 distinct groups of bison within Yellowstone National Park. To better understand the biology of Yellowstone bison, we investigated the potential for limited gene flow across this population using multilocus Bayesian clustering analysis. Two genetically distinct and clearly defined subpopulations were identified based on both genotypic diversity and allelic distributions. Genetic cluster assignments were highly correlated with sampling locations for a subgroup of live capture individuals. Furthermore, a comparison of the cluster assignments to the 2 principle winter cull sites revealed critical differences in migration patterns across years. The 2 Yellowstone subpopulations display levels of differentiation that are only slightly less than that between populations which have been geographically and reproductively isolated for over 40 years. The identification of cryptic population subdivision and genetic differentiation of this magnitude highlights the importance of this biological phenomenon in the management of wildlife species.     

Impact of commercial salt production on wetland quality and waterbirds on coastal lagoons in Ghana

A comparative study conducted on two saline coastal wetlands that have been developed into saltpans and two others (referred to as 'non-saltpans'), that are also saline but have no saltpans, describes the quality of lagoon water, benthic macroinvertebrates and waterbird communities characterising these wetlands. The wetlands were sampled monthly from September 2005–April 2006. Except for turbidity, which was significantly higher in the non-saltpans, (p < 0.05), all other physico-chemical parameters studied were not significantly different between the two wetland types (p > 0.05). The waterbird communities of the saltpans and non-saltpans, characterised by 48 and 50 species respectively, scored a Sorenson Index value of 0.88, indicating a high similarity. The population density of benthic macroinvertebrates in the saltpans and the non-saltpans was statistically similar (p > 0.05) but the population densities of waterbirds feeding exclusively on benthic macroinvertebrates were significantly higher in the non-saltpans (p < 0.05). Although the shallow ponds created for salt production might be providing more suitable feeding habitats for fish-eating birds, the development of these ponds has also reduced the exploitable area available to the birds feeding exclusively on invertebrates, requiring them to depend largely on the non-saltpans. Birds feeding exclusively on fish had significantly higher population densities in the saltpans (p < 0.05) than in non-saltpans. This was attributed to reduced efficiency of piscivory, due to the high turbidity associated with the non-saltpans. Waterbirds feeding on a wide range of food types showed no significant differences in their population densities (p > 0.05) in the two wetland types.     

Sources and extent of human disturbance to waterbirds in the UK: an analysis of Wetland Bird Survey data, 1995/96 to 1998/99

Capsule Less than 32% of counters record disturbance at their site, with differences in causes between coastal and inland sites.

Aim Wetland Bird Survey (WeBS) data were reviewed to investigate the sources and scale of potential disturbance to waterbirds in the UK.

Methods Between 1995/96 and 1998/99, WeBS volunteer counters recorded human activity and perceived waterbird disturbance during co-ordinated counts at wetland sites across the UK.

Results Over 68% of counters recorded no disturbance at their site and only a small proportion of these (< 2%) indicated very high levels. The frequency of disturbance peaked during the late summer. Just over 26% of disturbance events were attributed to human activities. The most perceived human-related disturbance was caused by people using motor-driven machines and shooters. Coastal waterbirds were more likely to be disturbed by walkers, shooters and large aircraft whereas those inland were more likely to be disturbed by motor-driven machines and unpowered boats.

Conclusions Volunteer-based surveys can be useful in monitoring the sources and distribution of potentially disturbing activities over large spatial scales.