Phylogeography, hybridization and Pleistocene refugia of the kob antelope (Kobus kob)

Mitochondrial DNA control region sequences and seven microsatellites were used to estimate the genetic structuring, evolutionary history and historic migration patterns of the kob antelope (Kobus kob). Ten populations were analysed, representing the three recognized K. kob subspecies: K. k. kob in west Africa, K. k. thomasi in Uganda and K. k. leucotis in Sudan and Ethiopia. Despite being classified as K. k. thomasi and being phenotypically identical to the kob in Queen Elizabeth National Park (NP), the Murchison Falls population in Uganda showed high genetic similarity with the phenotypically distinct K. k. leucotis populations in Sudan and Ethiopia. This was regardless of marker type. Pairwise comparisons and genetic distances between populations grouped Murchison with K. k. leucotis, as did the Bayesian analysis, which failed to find any genetic structuring within the group. We propose that the divergent phenotype and life-history adaptations of K. k. leucotis reflect the isolation of kob populations in refugia in west and east Africa during the Pleistocene. Subsequent dispersal has led to secondary contact and hybridization in northern Uganda between lineages, which was supported by high levels of genetic diversity in Murchison. The reduced variability observed in Queen Elizabeth NP reflects a small founder population from west Africa and in part the decimation of Uganda's wildlife during the country's political turmoil in the 1970s. Due to similarities in phenotype and ecology, and the joint evolutionary history of their mtDNA sequences, the taxonomic status of K. k. kob and K. k. thomasi as separate subspecies is called into question.     

The territorial system of the kob antelope (Kobus kob kob) in the Comoé National Park, Côte d'Ivoire

The territorial system of kob antelopes in the Comoé National Park, Côte d'Ivoire, was studied from March 1993 until April 1997. Whereas size and shape of territories remained constant between 1993 and 1994, the number of territories decreased from 1994 onwards. A decline of the population density probably led to the decline in territory numbers and also to variations in size and shape of the remaining territories. The decline of kob numbers is the result of heavy poaching in the study area. Whereas a lekking system was present in the study area prior to 1975 when the population density was approximately 14.4 kobs/km², males switched to the resource defence territorial system present today after the population density decreased to 12.5/km² in 1993 and finally to 2.3/km² in 1997. Compared to other research areas with higher population densities, territories in the Comoé National Park are larger, almost all adult males are capable to defend a territory, fights over territories are rare and loss of territory tenureship is almost exclusively due to the death of the territorial male. We suggest that those differences can all be related to the low population density in the study area.     

Demography of a West African kob (Kobus kob kob) population

The kob (Kobus kob kob) population studied in the Comoé National Park, Ivory Coast, suffered unsustainable losses to poaching before and during the investigation. This in turn did not only lead to low densities but also changed the population composition, resulting in a strong female bias in all age classes except juveniles. The relative rarity of adult males probably had negative effects on the population recruitment. Although mating occurred throughout the year and birth intervals were short, at least in some females, annual birth‐rate was low compared to earlier studies in the same area. Effective conservation measures are urgently needed to ensure the future existence of the studied population.     

Large sequence divergence of mitochondrial DNA genotypes of the control region within populations of the african antelope, kob (Kobus kob)

The genetic differentiation among kob populations (Kobus kob) representing two recognized subspecies was examined using mitochondrial control region sequences. Two distinct lineages (estimated sequence divergence of 9.8%) exhibited different geographical distributions and do not coincide with previously recognized ranges of subspecies. The presence of the two lineages was further supported with sequences of mitochondrial cytochrome b gene. One lineage was predominant in the west and southern ranges of the populations studied and the other was commonly found in a more northern distribution (Murchison populations) in Uganda. Murchison and the geographically intermediate Toro populations (Uganda) represented the area of overlap. The existence of the two lineages in the area of overlap is hypothesized to have resulted from a range expansion and secondary contact of the two lineages of kob that evolved in allopatry. The existence of the kob during the Pleistocene offers a plausible explanation for the observed biogeographic pattern. Our mitochondrial data reveal two examples of discordance between a gene tree and presumed species tree as: (i) the two lineages co-occur in the kob subspecies, Kobus kob thomasi (Uganda kob); and (ii) the puku, which was included in the analysis because of its controversial taxonomic status (currently recognized as a distinct species from the kob), is paraphyletic with respect to the kob. Significant degrees of heterogeneity were detected between populations. Relatively high genetic variation was observed in the populations, however, the inclusion of distinct lineages influences the population structure and nucleotide diversity of the kob populations.     

The forgotten Grevy's zebra Equus grevyi population along the Kasigau Corridor ranches,SE Kenya: recent records and conservation issues

Since the 1970s, the globally endangered Grevy's zebra Equus grevyi has suffered a substantial reduction in range and population size. Grevy's zebra was introduced into the Tsavo ecosystem in two translocations: 22 individuals released in Tsavo East National Park in 1964 and 30 individuals released in Tsavo West National Park in 1977. This study focuses on the Tsavo East subpopulation within the Kasigau Corridor REDD+ Project Area. Data were collected from 2011 to 2014 using systematic and ad lib methods, while vegetation stratification was based on tonnes of CO₂e per hectare. Cumulatively, 785 Grevy's zebra were seen in 210 encounters. The largest single group comprised of 24 individuals; mean group size was 4 ± 3. Foals comprised 10% of all individuals seen and were recorded across most months, suggesting year‐round breeding. The range core for the Grevy's zebra in this area was estimated to be 400 km². Its density was estimated at 0.09 ± 0.038 individuals per km², translating to a population of 36 ± 15 individuals (range: 6–67) based on the estimated core range. Grasslands and sparse Acacia–Commiphora vegetation strata were used significantly more than expected. Despite constituting only about 2–3% of the global Grevy's zebra population, this subpopulation could still play a role as a – disconnected – reserve population.     

Diet choice of large carnivores in northern Cameroon

The diet of African wild dogs, lions and spotted hyenas was studied in the woodland savannah of Faro National Park and surrounding hunting zones in northern Cameroon during the dry season. Faecal analysis revealed that the diet of the three large carnivores overlaps considerably. Frequencies of prey remains of large and medium‐sized antelopes were highest, with Buffon's kob being by far the most common prey species. Carnivores seem to consume most abundant prey species. No prey item of domestic livestock was found in the faeces. Faecal analysis has proved to be a useful method to reveal diet choice for large carnivores in northern Cameroon. Detailed information on the distribution and density of large carnivores and their prey is needed to give a better picture of the status of carnivores in northern Cameroon and to help resolve conflicts with livestock. Further investigations into the seasonal variation of predation and other factors structuring the large carnivore community in northern Cameroon are recommended.     

Spatial and temporal habitat use of kob antelopes (Kobus kob kob, Erxleben 1777) in the Comoé National Park, Ivory Coast as revealed by radio tracking

Spatial and temporal habitat use of kob antelopes (Kobus kob kob) have been investigated in the Comoé National Park (Ivory Coast, West Africa) by use of radio telemetry. A total of 23 kob were equipped with radio collars and radio tracked for up to 15 months. Home ranges of males were smaller and those of females larger than expected from theoretical models. Adult males used smaller areas than adult females and did not show seasonal home range shifts. Daily distances travelled did not differ between sexes. Kob walked less during the night than by day and covered shorter distances in the wet season. Whereas an increase in home range overlap between females resulted in higher rates of association among individuals, association of adults of mixed sexes was not correlated with the degree of home range overlap. Territorial behaviour of males and predator avoidance by females are suggested to explain the sex‐specific differences in home range size of adults and the deviation from the predicted sizes. Predator avoidance is presumed as the main reason for the reduced walking distances at night as well as in the wet season. Reproductive behaviour and feeding ecology are assumed to determine the degree of association of conspecifics.     

Uganda kob prefer high-visibility leks and territories

In lekking species, where males provide estrous females withlittle more than sperm, it has been widely supposed that theonly possible benefits to females of mate choice are genetic.We studied female choice of leks and territories in a reduncineantelope, the Uganda kob (Kobus kob thomasi), and found thatfemales consistently preferred high-visibility mating sites.Leks were elevated and had shorter grass and fewer thicketsthan the surrounding areas. Changes in the number of male andfemale kob on 10 leks were correlated with changes in surroundinggrass height, and both females and males preferred leks withexperimentally reduced grass height over neighboring controls.Within a lek, territory popularity was the primary determinantof male daily mating success, and females preferred territoriesrelatively far from thickets, but removal of thickets did notaffect female territory preferences. Because lion hunting successon kob increases with grass height and thicket density, femalesmay benefit directly from these preferences by reducing therisk of predation.     

Diet choice of large carnivores in northern Cameroon

The diet of African wild dogs, lions and spotted hyenas was studied in the woodland savannah of Faro National Park and surrounding hunting zones in northern Cameroon during the dry season. Faecal analysis revealed that the diet of the three large carnivores overlaps considerably. Frequencies of prey remains of large and medium‐sized antelopes were highest, with Buffon's kob being by far the most common prey species. Carnivores seem to consume the most abundant prey species. No prey item of domestic livestock was found in the faeces. Faecal analysis has proved to be a useful method to reveal diet choice for large carnivores in northern Cameroon. Detailed information on the distribution and density of large carnivores and their prey is needed to give a better picture of the status of carnivores in northern Cameroon and to help resolve conflicts with livestock. Further investigations into the seasonal variation of predation and other factors structuring the large carnivore community in northern Cameroon are recommended.     

Population status and habitat preference of Soemmerring’s gazelle in Alledeghi Wildlife Reserve,Eastern Ethiopia

This study was undertaken to determine the current population size, structure and habitat preference of Soemmerring's gazelle [Nanger soemmerringii (Cretzschmar 1828)] in the Alledeghi Wildlife Reserve, NE Ethiopia. Animals were counted, both during dry and wet seasons, along 12 line transects each in three habitat types (grassland, tree‐scattered grassland and bushland) in 2015/16. Habitat type had nonsignificant effect on mean population density of Soemmerring's gazelle, but wet season mean density was significantly higher than dry season mean density. Estimated weighted mean (±95% CI) population density of the species in the reserve was 1.90 (±0.17) and 5.99 (±0.370) individuals/km² during the dry and wet seasons, respectively. Total population size of the species in the Alledeghi Wildlife Reserve was estimated at 826 ± 77 and 2,562 ± 158 individuals during the dry and wet seasons, respectively. Over half of the total population of Soemmerring's gazelle was represented by adult females during both seasons. Seasonal habitat preference of Soemmerring's gazelle was statistically significant, with greater preference for grassland habitat during wet season and for bushland habitat during dry season. In conclusion, this study has provided valuable data that will be used as a baseline for future population monitoring.     

Food limitation and demography of a migratory antelope,the white-eared kob

Summary Although it is commonly presumed that many populations of large-herbivores are limited by food availability, supporting evidence is scarce. This hypothesis was investigated in a population of over 800,000 white-eared kob in the Boma National Park region of the southern Sudan. Food availability, body condition, and mortality rates of adults and calves were measured during the dry seasons of 1982 and 1983. Sampled age distributions from both the live population and carcasses were used to calculate age-specific rates of mortality. In 1982, food supplies during the dry season were augmented by substantial rainfall, which produced regrowth of grass in areas that ordinarily had little green forage. As a result, fat reserves declined little, and rates of adult mortality showed no increasing trend. Total adult mortality was 5%. In 1983, there was no rainfall during the dry season and food intake was insufficient to meet the estimated energy requirements of kob. As a result, fat reserves declined and adult mortality rates increased fourfold. Total adult mortality was 10% (equivalent to the recruitment rate of yearling into the population). Calf mortality during the dry season was similar in both years (50%), based on field estimates of mortality rates and calf/female ratios. Lactation throughout the dry season possibly provided a buffer for calves against variations in food availability. The age structure of the live population in 1983 suggests that a drought in 1980 reduced kob numbers by 40%. These results suggest that adult survival is influenced strongly by the availability of food during the dry season. However, the duration of the dry season also plays an important role. During the dry season, declining fat reserves make an increasing proportion of the population vulnerable to mortality. As a result, even moderate droughts may lead to substantial changes in population numbers.     

Armed conflict and development in South Sudan threatens some of Africa’s longest and largest ungulate migrations

Many terrestrial mammalian migrations are disappearing before they are documented. The Boma-Jonglei ecosystem in South Sudan, one of the world’s poorest and most conflicted countries, contains some of the largest, longest, and least studied ungulate migrations. A rapidly increasing human population, ongoing armed conflict, and looming oil development, however, threatens the migration of 800,000 white-eared kob (Kobus kob leucotis) and 160,000 tiang (Damaliscus lunatus tiang) in this system. To document these migrations and identify potential conflicts, we examined the movements of ungulates in the Boma-Jonglei ecosystem using data from 14 collared individuals (12 kob, 2 tiang). We identified two separate dry season ranges of kob; from each, kob initiated migration with the onset of the rainy season, and migrated to a shared rainy season range also shared by the tiang. The maximum straight-line distance between telemetry locations of kob (399 km) and tiang (298 km) on their dry and rainy season ranges indicated these migrations were among the longest in Africa. The kob range was 68,805 km², 29% of which was within national parks and 72% within leased oil concessions (54–83% of parks overlap with potential oil concessions). The range of the tiang (35,992 km²) occurred almost entirely (> 99%) within land leased to oil companies. Because disruption or elimination of these migrations will inevitably lead to significant population reductions, maintenance of the migration routes we identified through additional protection measures are essential to conserve one of the largest ungulate aggregations in the world.     

Recent status and life history traits of endangered soft‐mouth trout,Salmo obtusirostris in the River Neretva catchment (Bosnia and Herzegovina) as a consequence of river alteration

Soft‐mouth trout, Salmo obtusirostris has disappeared from most of its historical distribution range in the River Neretva catchment. Remnant groups are highly fragmented and distribution of the species is restricted to only 15% of it's historical area. The most abundant length range of remnant individuals is between 20 and 40 cm; with a significant decrease of the bigger individuals. Age population structure is dominated by younger fish aged 2, 3 and 4 years, however, age class 4⁺ and 6⁺ predominated in the lower river part. Specimens older than 8 years were not observed, and estimated fishing mortality (F) was high, particularly in the upper part of the river (0.786). The River Neretva soft‐mouth trout population is under heavy pressure including anthropogenic habitat changes and illegal fishery, leading to disappearance in number of formerly inhabited areas. The Upper and Lower Neretva are the only areas where the species is still abundant. However, the collapse of the number of old individuals increases the risk of extinction of the remaining wild subpopulations.     

Fire induced changes in the foraging behaviour of impala Aepyceros melampus in Lake Mburo National Park, Uganda

The impact of fire on the foraging behaviour of impala (Aepyceros melampus), was studied in the Lake Mburo National Park, Uganda. Two indices of foraging efficiency were used to establish differences in feeding behaviour in burnt and unburnt control areas. These are acceptable grass/browse abundance (AGA/ABA), expressed in terms of feeding time achieved per 50 steps and food ingestion rate (FIR), expressed as the cumulative percentage. Accumulation of above ground grass biomass was also measured in burnt and control areas. After burning, the grazing efficiency remains constant throughout the dry season, while the browsing time achieved per 50 steps decreases drastically. In the control areas AGA decreased with increasing length of the dry season while ABA increased. When expressed in terms of cumulative percentage (FIR), the results show a significant increase of 31% in foraging time spent grazing and a 24% decrease in foraging time spent browsing, in burnt areas. The results confirm the classification of impalas as intermediate or mixed feeders with a distinct preference for grass. Impala foraging patterns after burning are discussed and compared with investigations on the effect of burning on the behaviour of impalas and Buffon's kob (Kobus kob kob) in other areas of Africa.     

Effects of age,size, and density on natural survival for an important coral reef fishery species,yellow tang, <Emphasis Type="Italic">Zebrasoma flavescens</Emphasis>

Hundreds of thousands of juvenile yellow tang, Zebrasoma flavescens, are caught each year in the state of Hawai’i (USA) for the live aquarium trade. As part of an extensive adaptive management strategy built around a network of protected areas, an emphasis was placed on understanding this important species’ life history. Multiple capture-mark-recapture techniques and a model selection approach to data analysis in Program MARK were used to estimate the effects of individual age and conspecific density on natural per-capita daily survival probabilities of yellow tang recruits (recently settled individuals, 30–50 mm total length) and the effects of body size and site on natural per-capita monthly survival probabilities for juveniles (58–127 mm total length). The models of recruit survival that included additive effects of density and age were best supported by the data and indicated an increase of survival with age and decrease of survival with increased conspecific density. At 1 day post-settlement, the model averaged daily per-capita survival probability ranged from 0.963 (95% CI: 0.932–0.981) at a low density of 0.1 recruits m⁻² to 0.848 (95% CI: 0.752–0.911) at a high density of 1.3 recruits m⁻². The best supported model of juvenile survival had no effect of fish length or site, with a constant monthly per-capita survival of 0.939 (95% CI: 0.925–0.950). Only about 1% of recruits may survive to adulthood when protected from fishing. These results can be used to better analyze and interpret data from protected area monitoring surveys and refine management practices. Continued long-term monitoring, combined with targeted life history studies and demographic modeling, is needed to further investigate the population level effects of fishing yellow tang juveniles.     

Population dynamics and social organization of sambar (Rusa unicolor unicolor) in Horton Plains National Park,Sri Lanka

We estimated the population density and investigated the social organization of sambar (Rusa unicolor unicolor) in Horton Plains National Park (HPNP), Sri Lanka. Distance sampling was conducted along six strip transects every month for a period over 3 years (2018–2020) to estimate the density of the sambar population in grasslands of HPNP (9.4 km²), while the antler stage of males and the behavior of individuals were recorded to describe the population's reproductive stage and hence the social organization. Population density estimates showed relative stability over the 3 years and varied over the seasons but with consistent peaks from year to year with the highest population densities recorded in November–December (212.93 ± 25.38 animals/km² in 2018, 187.91 ± 28.51 in 2019, and 179.76 ± 31.85 in 2020). The highest percentage of males in hard antlers was observed from November through January, while the percentage of antlers cast sambar peaked from March to April each year. Hinds were observed with newborn calves throughout the year, but the highest number of newborn calves were recorded from July to August each year, while the number of calves counted each year varied from 210 to 267 individuals. The mean group size was variable throughout each year with the largest groups recorded from September to December (up to 52), the period accompanied by the most observations of mating and sparring behavior. Although on a tropical island, HPNP is situated on a rolling plateau landscape in the highlands, where sambar showed a degree of reproductive seasonality somewhat similar to temperate cervid species.     

Integrating sign surveys and telemetry data for estimating brown bear (Ursus arctos) density in the Romanian Carpathians

Accurate population size estimates are important information for sustainable wildlife management. The Romanian Carpathians harbor the largest brown bear (Ursus arctos) population in Europe, yet current management relies on estimates of density that lack statistical oversight and ignore uncertainty deriving from track surveys. In this study, we investigate an alternative approach to estimate brown bear density using sign surveys along transects within a novel integration of occupancy models and home range methods. We performed repeated surveys along 2‐km segments of forest roads during three distinct seasons: spring 2011, fall‐winter 2011, and spring 2012, within three game management units and a Natura 2000 site. We estimated bears abundances along transects using the number of unique tracks observed per survey occasion via N‐mixture hierarchical models, which account for imperfect detection. To obtain brown bear densities, we combined these abundances with the effective sampling area of the transects, that is, estimated as a function of the median (± bootstrapped SE) of the core home range (5.58 ± 1.08 km²) based on telemetry data from 17 bears tracked for 1‐month periods overlapping our surveys windows. Our analyses yielded average brown bear densities (and 95% confidence intervals) for the three seasons of: 11.5 (7.8–15.3), 11.3 (7.4–15.2), and 12.4 (8.6–16.3) individuals/100 km². Across game management units, mean densities ranged between 7.5 and 14.8 individuals/100 km². Our method incorporates multiple sources of uncertainty (e.g., effective sampling area, imperfect detection) to estimate brown bear density, but the inference fundamentally relies on unmarked individuals only. While useful as a temporary approach to monitor brown bears, we urge implementing DNA capture–recapture methods regionally to inform brown bear management and recommend increasing resources for GPS collars to improve estimates of effective sampling area.     

Diversity, regeneration status and socio-economic importance of the vegetation in the islands of Lake Ziway, south-central Ethiopia

This study was conducted in the islands of Lake Ziway located in the main Ethiopian Rift Valley in south-central Ethiopia. Its main objective was to investigate the diversity, regeneration status, socio-economic importance and the factors that cause degradation of the plant resources in the islands. A total of 73 relevés, measuring 20×20 m, were established along line transects laid from the central part of each island to the lake edge in eight aspects. Herbaceous species were sampled by using a 2×2 m sub-relevé laid within each relevé. In each relevé, the cover/abundance of each species was estimated, woody species were counted, diameter at breast height and height of trees and shrubs and the environmental variables altitude, slope, aspect and position were measured. Participatory Rural Appraisal was employed to generate the socio-economic information. A total of 141 species belonging to 113 genera and 55 families were identified, of which 18.4% were trees, 21.3% trees/shrubs, 12.1% shrubs, 3.5% lianas, 4.3% herbaceous climbers and 40.4% herbs. The overall Shannon diversity and evenness of woody species in the islands were 2.60 and 0.62, respectively. The number of species on the islands correlated with island's size, habitat diversity and degree of human disturbance. The similarity in species composition between the islands was low, indicating that each island has its own unique flora. Nine plant communities were recognized and described. The total density and basal area of the vegetation were 2979 individuals ha⁻¹ and 191 m² ha⁻¹, respectively. The importance value index and the diameter and height class distribution revealed that some species are threatened and need the highest priority for conservation. The socio-economic survey showed that the island communities are highly dependent on the natural vegetation for various purposes. On the other hand, the islanders have maintained the soil and vegetation resources for centuries through their indigenous resource management systems and practices. Human population growth coupled with farmland expansion, soil erosion, free grazing and cutting trees for various purposes are the major threats to the vegetation resources in the islands. The implications of the results are discussed and recommendations are suggested for conservation, management and sustainable utilization of the fragile island ecosystems.     

Methods for lion monitoring: a comparison from the Selous Game Reserve,Tanzania

The Selous Game Reserve in Tanzania is believed to contain Africa's largest population of lions (Panthera leo), making it a popular destination for trophy hunters and photographic tourists. However, a lack of recent data has raised concerns about the conservation status of this iconic population, so we collected two types of population data between 2006 and 2009. First, we identified 112 individual animals in an 800 km² study area in the photographic tourism part of Selous, giving a density of 0.14 individuals km^?2. This density estimate was similar to results using the same method from 1997 to 1999, but the adult sex ratio has decreased from 1 male : 1.3 female in 1997 to 1 male : 3 females in 2009. Second, using buffalo calf distress calls, we conducted call‐up surveys to census lions in three hunting sectors in the west, east and south of Selous and in the northern photographic area. Estimated adult lion densities varied from 0.02 to 0.10 km^?2, allowing an overall population estimate of 4,300 (range: 1,700–6,900). Our results highlight the value of call‐ups in surveying cryptic hunted carnivores but stress the importance of long‐term projects for calibrating the responses to call‐ups and for measuring trends in demography and population size.     

Abundance and distribution of American beaver, Castor canadensis (Kuhl 1820), in Tierra del Fuego and Navarino islands, Chile

Castor canadensis specimens were imported from Canada and released in the wilderness on the Argentinean part of Tierra del Fuego (TDF) in the year 1946. First studies on the development of the beaver population and subsequent environmental changes were conducted four decades later and indicated a strong expansion of these animals, with negative effects on the forest, especially the dominant Nothofagus sp. Between 1999 and 2001, we investigated the density of the beaver population in the Chilean part of TDF and the southern adjacent island Navarino (NAV). Data were mapped into a geographical information system. The mean colony density was 1.03 (range: 0.15–1.91) and 1.1 per km watercourse for 75% of the area of TDF (mainly south and central region) and the total NAV island, respectively. The average number of individuals estimated per colony was five. Based on these findings, the number of beavers in the Chilean part of TDF and on NAV was estimated at 61,300 individuals. The population is increasing and expanding in the Northern region, with a linear rate of 2.6–6.3 km/year.