Life cycle and morphology of Anisops sardeus Herrich-Schaeffer, 1849 (Heteroptera: Notonectidae)

The life cycle of Anisops sardeus was studied by rearing individuals from egg to adult stage in laboratory conditions at a water temperature of 23.2 ± 1.4 °C during the wet season (May-June) and 19 ± 1.8 °C during the dry season (December-February). The incubation period averaged 8 ± 0.8 and 11.5 ± 1.7 days during the wet and dry seasons, respectively. Duration of the five instars averaged 3.4 ± 0.5, 4.4 ± 0.5, 4.8 ± 0.8, 5 ± 0.7, and 6.9 ± 0.7 days, respectively during the wet season, and 4.9 ± 0.7, 6.5 ± 1.1, 7.5 ± 1.1, 8.1 ± 0.7, and 9.4 ± 1.1 days, respectively during the dry season. Total developmental time averaged 32.5 ± 2 and 47.9 ± 2.8 days in the wet and dry seasons, respectively. The average period of incubation and developmental time of the five instars were shorter in the wet season as compared to those in the dry season. But individuals were larger in the dry season. The variations in morphometric ratios of different characteristic features of laboratory reared specimens among different developmental stages in both the wet and dry seasons, and field collected specimens in the wet season were highly significant as revealed by one-way MANOVA (F = 95.45, p < 0.001; F = 124.38, p < 0.001; F = 5022.85, p < 0.001, respectively). Five instars are described in detail with emphasis on 29 morphometric ratios. This study discerned six morphometric ratios such as length of wing pad/ width of wing pad (WL/WW), length of wing pad/body length (WL/BL), length of head/length of body (HL/BL), length of meso femur/length of meso tibia (FE2L/TI2L), synthlipsis/width of head (S/HW), and vertex/synthlipsis (V/S) which can be used for discriminating instars I-V.     

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.     

Population structure and ecology of the African buffalo (Syncerus caffer Sparrman, 1779) in Chebera Churchura National Park,Ethiopia

An investigation of population structure and ecology of the African buffalo (Syncerus caffer Sparrman, 1779) was carried out in the Chebera Churchura National Park, Ethiopia during the wet and dry seasons of 2005–2006. Sample counts of African buffaloes were carried out in an area of 1,215 km². The estimated population of buffalo was 2,617 individuals. Males comprised 35.0%, while females 52.8% of the population. The remaining 12% of the population was young of both sexes and of all ages of unknown sex. It was difficult to categorize the young into male and female in the field, as their primary sexual characteristics were not easily visible. Male to female sex ratio was 1.00 : 1.51. Age structure was dominated by adults, which constituted 72.06% of the total population. Subadults comprised 22.02%, and young accounted for 5.9% of the population. Larger herds of up to 27 individuals were observed during the wet season and smaller herds of eight individuals during the dry season. The mean herd size during wet and dry seasons was 24.81 and 7.77, respectively. The African buffaloes were distributed in four habitat types such as grasslands, woodlands, montane forests and riverine habitat in the study area. They were observed more in the riverine vegetation types during the dry season. Relative abundance of food resources, green vegetation cover and water availability in the area were the major factors governing their distribution in the present study area. They spent a greater proportion of the time in feeding and resting/ruminating activities. On the average, 49.7% of the daytime was spent in feeding, and 38.75% of the day on resting (lying down and standing). Morning and the late afternoon activity peaks were more pronounced during the dry season than the wet season.     

Diurnal activity budget of African buffalo (Syncerus caffer Sparrman, 1779) in Chebera Churchura National Park,Ethiopia

One of the fundamental questions in animal ecology concerns the activity pattern of animals and the environmental and intrinsic factors that influence such dynamics. This study tested the hypotheses that activity time budgets of the African buffalo appeared to vary by season and times of day and predicted that buffalo would express unequal proportion of time for different activity patterns during the wet and dry seasons in Chebera Churchura National Park (CCNP). An investigation on the diurnal activity budget of the African buffalo was carried out during the wet and dry seasons of 2012–2014 in the Chebera Churchura National Park, Ethiopia, using focal‐animal sampling method. Buffalo spent a greater proportion of the time in feeding and resting/ruminating activities in both the wet and dry seasons. Feeding and resting (lying down and standing) were the predominant activities (87.14% of the diurnal active period), 48.95% time spent feeding during the dry season and 44.91% during the wet season. There was a significant decrease in feeding and an increase in resting from dry seasons to wet seasons. Daytime grazing and resting periods during the wet season were estimated to be 5.39 h and 4.98 h, respectively. Morning and the late afternoon activity peaks were more pronounced during the dry season than the wet season. Therefore, feeding and resting time was influenced by the time of day and the seasons. But there were no significant difference in time allocation for other activities in both the wet and dry seasons. The study has implications for understanding animal activity budget across species, particularly relationships between temperature and season.     

Activity pattern of the brown howler monkeyAlouatta fusca,Geoffroy 1812, in a forest fragment of southeastern Brazil

A group of six brown howlers was studied during a year in the Santa Genebra Reserve, a 250ha-forest fragment near the city of Campinas, State of São Paulo, southeastern Brasil. On average, the group rested for 64% of the daylight hours and feeding and moving occupied 18% and 13% of this period, respectively. A greater proportion of time was spent feeding during dry season (24%) than the wet season (15%), and the reverse observed for time spent resting (59% and 69% of the group's daylight hours during dry and wet seasons, respectively). The increase of resting and decrease of feeding during wet season were related to the percentage of leaves in the group's diet, high even during the fruiting season (wet season). However, additional data of other groups are necessary to draw conclusions about the effects of habitat disturbance on this population.     

Ecological determinants of herd size in the Thornicroft’s giraffe of Zambia

Ecological factors have a pervasive impact on animal population sizes and the structure of their social systems. In a number of ungulate species, predator pressure exerts a major influence on group size. Given that giraffe (Giraffa camelopardalis) live in an extremely flexible social system, and that breeding is nonseasonal, they are an ideal species for examining how ecological variables contribute to fluctuations in herd size. We present an analysis of 34 years of data on a population of Thornicroft’s giraffe (G. c. thornicrofti Lydekker 1911) that reveal how herd size changes with season and habitat. Sex differences in herd size were apparent, with bulls often travelling as singletons, whereas cows were generally observed with conspecifics. Herds were larger during the wet than dry season, but herd size changed in a parallel fashion across habitats. Giraffe herds were smaller in woodland and thicket areas than in open habitats, regardless of season. We suggest that the regular fluctuations in herd size among giraffe indicate a fission/fusion social system embedded within a larger social community. We conclude that changes in herd size among giraffe reflect a dynamic process regulated by individuals adjusting the number of associates based upon an interaction of foraging, reproductive, social and antipredator strategies.     

Habitat Exploitation by Free-ranging Saguinus niger in Eastern Amazonia

We monitored the foraging behavior of the members of a group of black-handed tamarins (Saguinus niger) at a site in eastern Amazonia. Their diet was frugivorous-insectivorous, but also included pod exudate of Parkia pendula. The focal group used all 3 types of forest—primary, logged, and secondary— in all months, but differentially between seasons. In the dry season, tamarins spent more than half of activity time in primary forest and less than a third in secondary forest whereas during the wet season, the proportions were reversed. Data on resource abundance indicated that the shift in habitat preference is related to a seasonal change in the distribution of fruit sources, with a larger number of species and individuals fruiting during the wet season. We recorded no such variation in the abundance of arthropods. While using a larger area, including more secondary forest, during the wet season, the group traveled significantly shorter distances each day, reflecting the availability of a larger number of fruit sources. Overall, the results reemphasize the ecological and behavioral flexibility of Saguinus niger and their ability to cope with habitat disturbance.     

Seasonal variation in activity and diet in a small-bodied folivorous primate,Hapalemur griseus,in southeastern Madagascar

How small-bodied (500–1,200 g) folivorous prosimian primates cope with large amounts of foliage in their diet seasonally has yet to be determined for many species such as Hapalemur griseus, which specializes on bamboo. To address this issue, we present results on seasonal variation in activity and diet from a wild group of H. griseus in southeastern Madagascar. Throughout the study (which was conducted from July–November 1994 and July 1995–February 1996), H. griseus primarily fed on new growth from three species of bamboo: two species of liana bamboo and Cephalostachyum perrieri. Bamboo species were used in different ways seasonally; liana bamboo was consumed more during the dry, cool season, and C. perrieri was eaten more often during the wet, warm season. H. griseus also spent more of their time feeding and traveling than nocturnal folivores of similar body size during the dry season. During the warm wet season, H. griseus decreased the amount of time spent feeding and traveling and rested more often. We hypothesize that seasonal changes in activity may be primarily related to the distribution and availability of food sources and/or reproductive cycles. Am. J. Primatol. 43:211–223, 1997. © 1997 Wiley-Liss, Inc.     

Effect of Seasonality on the Behavior of an Insectivorous Primate, Tarsius spectrum

The distribution and quality of food resources is generally recognized as the preeminent factor explaining much interspecific and intraspecific variation in the behavior of nonhuman primates. Primates that live in seasonal environments often show predictable responses to fluctuating resources. In order to compensate for the reduction in resource availability, primates variously switch to alternative, poorer quality food sources, increase the amount of time they spend foraging, or increase their daily path length. Some primate species reduce their group size or maximize the group dispersion. I address whether spectral tarsiers (Tarsius spectrum), which are insectivores, modify their behavior in the same ways as frugivores and folivores in response to seasonal or scarce resources. My results indicate that wild spectral tarsiers modify their activity budget in response to seasonal resources. Specifically, during periods of low resource availability, spectral tarsier males and females spent more time traveling and foraging compared to their activity budget during the wet season. Males and females not only increased the amount of time they spent foraging during times of low resource abundance but also modified their foraging behavior. During the wet season, when resource abundance was high, they consumed Orthoptera and Lepidoptera with greater frequency than during the dry season. During the dry season, when resource abundance was low, spectral tarsiers still ate numerous Orthoptera and Lepidoptera, but they also increased consumption of Coleoptera and Hymenoptera. Spectral tarsiers were also more likely to be involved in territorial disputes during the dry season than during the wet season. Intragroup encounters decreased in frequency in the dry season versus the frequency of encounters during the wet season.     

Seasonality affects leaf nutrient and condensed tannin concentration in southern African savannah browse

Trees that maintain some leaves throughout dry seasons become important ruminant browse depending on nutritive and antinutritive values. Leaves from seven tree species that maintained some leaves during the dry season were collected during dry and wet seasons and analysed for nutritive and antinutritive values. Neutral detergent fibre of leaves was either not different or less (P ≤ 0.05) during the dry season as compared to the wet season depending on species. Acid detergent fibre was either not different or greater (P ≤ 0.05) during the dry season as compared to the wet season. Crude protein and condensed tannins (CT) were either not different or less (P ≤ 0.05) during the dry season than during the wet season for the seven species. The biological activity (protein‐binding ability; PB) of the CT was highly species specific and was either not different between seasons, more bioactive during the wet season, or more bioactive during the dry season depending on the species. Based on combinations of low fibre, high protein and potentially beneficial levels of bioactive CT, Senegalia caffra, Vachellia karoo and Searsia lancea may be the most promising dry‐season browse of the species studied.     

Maintenance behavior of cattle in a young tree plantation in southern Kyushu,Japan

This 4-year study monitored maintenance behavior of beef cattle (Japanese Black) foraging in a young Chamaecyparis obtusa (an evergreen conifer) plantation in southwestern Japan. The animals spent 551 ± 8 min (mean ± SE) per day grazing, 436 ± 4 min ruminating, 313 ± 9 min resting, 44 ± 2 min moving, and 96 ± 4 min on other activities. Grazing activity was high during 0600–1800 h and low during 2200–0600 h. Ruminating activity was high during 2200–0600 h and low during 0600–1800 h. Resting activity was high during 2200–0600 h and low for the remainder of the day. Air temperature was not a dominant factor determining the daily duration of grazing, rumination, or resting. The activity of the animals was usually synchronized, with the degree of synchronization being highest in grazing followed by ruminating and resting. Daily liveweight change of the animals was positively related with daily ruminating time, i.e., animals gained more when they ruminated longer. The maintenance behavior of cattle in the young tree plantation, as compared with that on grasslands, is characterized by (1) high grazing activity around midday, (2) low ruminating activity in the daytime, and (3) midday adjustment of the daily total grazing time. Daily rumination time may be used as an indicator of animal performance on the bases of a herd (not individual animals) and a period of 2–15 weeks (not individual days).     

Variation in Spatial Cohesiveness in a Group of Japanese Macaques (<Emphasis Type="Italic">Macaca fuscata</Emphasis>)

The spatial cohesiveness of a group is an important element that characterizes the social structure of group-living species. Moreover, remaining cohesive is crucial if individuals are to coordinate their activities and reach collective decisions. We measured interindividual spacing in a group of wild Japanese macaques (Macaca fuscata) to assess the spatial cohesiveness of a social group quantitatively. We used simultaneous focal animal sampling, with 2 observers recording individuals’ locations with a global positioning system (GPS) during 3 seasons. Interindividual distances differed among seasons; they were short in autumn (mean ± SD: 25.6 ± 20.1 m), intermediate in winter (mean ± SD: 46.3 ± 35.7 m), and long in summer (mean ± SD: 62.3 ± 47.1 m). Measurements taken in summer revealed extremely wide spacing (maximum: 1225 m), suggesting subgrouping. Distances also varied with activity during each season; they were short during resting and grooming, intermediate during foraging, and long during moving. Group cohesion was also influenced by food distribution. More group members were ≤20 m of the focal individual during foraging on clumped food than foraging on scattered food in each season, and the group foraged on clumped food most frequently in autumn. Individuals were also likely to aggregate at resting/grooming sites and clumped food patches and to disperse when moving within a day. These results demonstrate that Japanese macaques show considerable variation in spatial cohesiveness both within short time periods, e.g., 1 d, and among seasons, and that they adjust group cohesiveness flexibly depending on the food conditions and foraging tactics.     

Seasonality in foraging behaviour of Constrictotermes cyphergaster (Termitidae, Nasutitermitinae) in the Caatinga of Northeastern Brazil

The foraging activity of Constrictotermes cyphergaster was investigated in the Caatinga of Northeast Brazil. Eight colonies were monitored for seven days, during both dry and wet seasons. Foraging activity occurred in exposed columns at night, generally between 22:00 and 05:00 h. During the wet season, foraging activity was significantly higher, with one bout every 1.6 ± 0.2 days, than the dry season, when foraging bouts were performed every 1.9 ± 0.3 days. Foraging activity throughout the study colonies presented high temporal synchronization. In both seasons, foraging was negatively correlated with air temperature and positively correlated with humidity. The foraging trails were often re-utilized and ranged from 1 to 18.5 meters in length. No difference between seasons in the area potentially utilized by the study colonies was observed. Approximately 51000 individuals participated in the foraging bout during the dry season, whereas some 87000 individuals participated in the foraging bout during the wet season. This corresponds to 43 and 74% of the estimated total nest population for the dry and wet seasons respectively. The average ratio soldiers:workers during foraging was 1:1.2 in the dry season and 1:2 in the wet season. The higher frequency and number of individuals foraging during the wet season in the present study are likely to be a strategy from C. cyphergaster to store energy reserves to be utilized during the dry season. Received 28 November 2005; revised 29 May 2006 and 16 August 2006; accepted 1 September 2006.     

Coping with a challenging environment: effects of seasonal variability and reproductive status on glucocorticoid concentrations of female baboons (Papio cynocephalus)

Environmental stressors impact physiology and behavior in many species of animals. These effects are partly mediated through changing concentrations of glucocorticoids, which also vary with reproductive state and social conditions. Prior research has focused largely on seasonal breeders, but the close temporal linkage between season and reproductive state in these species hinders ability to disentangle environmental effects from those of the animal's reproductive status. Here we assessed the effects of environmental challenges on the fecal glucocorticoid (fGC) levels of non-seasonal breeders, female baboons (Papio cynocephalus) of Amboseli, Kenya. Amboseli is characterized by a long dry season, during which food and water become scarce, and by extreme temperatures above 40 °C in the shade during some months of the year. We found that after accounting for female reproductive status and individual variability, females exhibited higher fGC levels during the dry season than during the wet season. Further, during the wet season, fGC levels were higher in months of high average daily maximum temperatures. During the dry season, fGC levels were elevated both in hotter months and in months during which the baboons spent a relatively high proportion of time feeding. In spite of these stressors, female baboons reproduce during all months of the year in Amboseli, unlike most other mammals in this environment. This may be attributable to their extreme adaptability, specifically their diversified diet, and their ability to modify their behavior, including their activity profiles.     

Drought effects on photosynthesis of the mangrove, Avicennia germinans, under contrasting salinities

 Drought effects on leaf photosynthesis of A. germinans growing under two contrasting salinities were studied in a Venezuelan fringe mangrove. During both wet and dry seasons, severe chronic-photoinhibition at predawn was not observed but strong down regulation occurred at midday during both seasons. Carbon assimilation rates (A, μmol CO₂ m⁻² s⁻¹) declined during the dry season from 11.9±1.8 to 7.0±1.5 and from 9.6±2.0 to 4.7±2.5 in plants from low and high salinity sites, respectively. Changes in carbon assimilation per unit of chlorophyll (A/Chl, mmol CO₂ mol⁻¹ Chl) were from 31.6±4.7 to 20.5±4.3 and from 21.9±4.7 to 15.2±8.2 in the low and high salinity plants, respectively. Therefore, neither changes in Chl nor seasonal differences in photoprotective down regulation could account fully for the decrease in leaf photosynthesis during drought. A reduction in CO₂ diffusion due to lowered stomatal conductance was not large enough to explain such a dramatic effect of drought on leaf photosynthesis. Stomatal response could be mitigated by the capability of A. germinans for osmotic adjustment under high salinity and/or drought. However, this intracellular salt accumulation may reduce carbon assimilation capacity further by decreasing the metabolism of leaf cells, increasing dark respiration and/or photorespiration. Received: 10 June 1998 / Accepted: 5 October 1998     

Nocturnal and seasonal patterns of carbon isotope composition of leaf dark-respired carbon dioxide differ among dominant species in a semiarid savanna

The C isotope composition of leaf dark-respired CO₂ (δ¹³C_l) integrates short-term metabolic responses to environmental change and is potentially recorded in the isotopic signature of ecosystem-level respiration. Species differences in photosynthetic pathway, resource acquisition and allocation patterns, and associated isotopic fractionations at metabolic branch points can influence δ¹³C_l, and differences are likely to be modified by seasonal variation in drought intensity. We measured δ¹³C_l in two deep-rooted C₃ trees (Prosopis velutina and Celtis reticulata), and two relatively shallow-rooted perennial herbs (a C₃ dicot Viguiera dentata and a C₄ grass Sporobolus wrightii) in a floodplain savanna ecosystem in southeastern Arizona, USA during the dry pre-monsoon and wet monsoon seasons. δ¹³C_l decreased during the nighttime and reached minimum values at pre-dawn in all species. The magnitude of nocturnal shift in δ¹³C_l differed among species and between pre-monsoon and monsoon seasons. During the pre-monsoon season, the magnitude of the nocturnal shift in δ¹³C_l in the deep-rooted C₃ trees P. velutina (2.8 ± 0.4‰) and C. reticulata (2.9 ± 0.2‰) was greater than in the C₃ herb V. dentata (1.8 ± 0.4‰) and C₄ grass S. wrightii (2.2 ± 0.4‰). The nocturnal shift in δ¹³C_l in V. dentata and S. wrightii increased to 3.2 ± 0.1‰ and 4.6 ± 0.6‰, respectively, during the monsoon season, but in C₃ trees did not change significantly from pre-monsoon values. Cumulative daytime net CO₂ uptake was positively correlated with the magnitude of the nocturnal decline in δ¹³C_l across all species, suggesting that nocturnal δ¹³C_l may be controlled by ¹³C/¹²C fractionations associated with C substrate availability and C metabolite partitioning. Nocturnal patterns of δ¹³C_l in dominant plant species in the semiarid savanna apparently have predictable responses to seasonal changes in water availability, which is important for interpreting and modeling the C isotope signature of ecosystem-respired CO₂.     

Feeding ecology of Lilian’s Lovebird Agapornis lilianae in Liwonde National Park,Malawi

Lilian's Lovebird Agapornis lilianae is a small, near-threatened parrot resident in mopane Colophospermum mopane woodlands. We investigated its diet and foraging behaviour in Liwonde National Park, Malawi. We expected that Lilian's Lovebirds would show little specialisation for a particular food source but generally feed on available seeds, fruits, flowers and other items as observed in other lovebirds. Lilian's Lovebirds fed on 30 different plant species. Lilian's Lovebirds were observed feeding in six habitat types in Liwonde National Park and adjacent areas during the wet season, and four in the dry season. In the wet season lovebirds (23% of observations) foraged in grassy wetland (dambo) areas the most, whilst in the dry season they foraged in grasslands with tree cover (18%) the most. In mopane woodland, foraging flock sizes differed significantly between the wet (mean = 19.8 ± 1.0 lovebirds) and dry season (mean = 33.6 ± 2.3 lovebirds). Grass seeds were lovebirds’ main food source from December to June. The nutritional analysis of preferred foods showed that grass seeds have a relatively high protein and energy content. Grass seed availability is reduced with savanna burning and so early season burning (before May–June) in areas in and outside the park is not recommended.     

Activities and feeding behavior of free-ranging pregnant baboons

The activities and feeding behavior of pregnant baboons, Papio cynocephalus,were studied in two free-ranging groups in Amboseli National Park, Kenya. Both the environmental conditions and the age of their fetuses influenced females’ activity budgets and feeding behavior. Females fed more and rested less during the dry season than during the wet season, and most females spent progressively more time feeding and less time grooming than expected (based upon the amount of recent rainfall) as their fetuses matured. During the wet season, females also devoted significantly greater proportions of feeding time to consumption of grass blades, leaves, and flowers and significantly smaller proportions of their feeding time to feeding upon seeds, corms, and fruit. As their fetuses became older, the proportion of time spent feeding upon seeds increased, and the proportion of time spent feeding upon grass blades and fruit declined.     

Spatial ecology and habitat use of giraffe (Giraffa camelopardalis) in South Africa

The lack of long-term studies remains a limiting factor in understanding the home range, spatial ecology and movement of giraffes. We equipped eight giraffes with GPS satellite units and VHF capacity, which were built in to the collars for the remote collection of data on their movements and home ranges over two years on Khamab Kalahari Nature Reserve (KKNR) within the Kalahari region of South Africa. Giraffe numbers in KKNR dropped from 135 individuals to 111 in just five years, revealing the lack of knowledge about their required habitat needs, space use and diet. With over 1000 km² available for roaming within the reserve, habitat selection, principle and preferred food species played a significant role in home range size and overlap between individuals. These giraffes used an average annual home range of 206 km² (20 602 ha) as calculated by a 95% minimum convex polygon (MCP) with a standard deviation core home range calculated by a 50% MCP of 10.1 km² to satisfy their annual needs for survival and reproduction in their preferred vegetation. In the wet, hot season (summer: December–February) when food was abundant, giraffes frequented smaller areas (average 177 km²), while in the dry, cool season (winter: June to August) the mean home range size increased to approximately 245 km². Rainfall influenced spatial distribution since it determined vegetation productivity and leaf phenology. The different seasons influenced giraffe movements, while different vegetation types and season influenced their home range size. Season and food availability also influenced home range overlap between different giraffe herds. Home range overlap occurred when giraffes were forced to roam in overlapping areas during the dryer months when the winter deciduous nature of the majority of the tree species resulted in lower food availability. In winter, the overlap was approximately 31% and in autumn approximately 23%. During the wet and warmer months, overlapping was 15% in summer and 19% in spring, respectively. The percentage of time spent in different vegetation type areas was influenced by the abundance of the principal food species of that plant community. It is thus concluded that the movements of giraffes were primarily influenced by a combination of environmental factors such as season, rainfall and vegetation density.     

Fine‐scale habitat heterogeneity influences browsing damage by elephant and giraffe

Effects of large mammalian herbivores on woody vegetation tend to be heterogeneous in space and time, but the factors that drive such heterogeneity are poorly understood. We examined the influence of fine‐scale habitat heterogeneity on the distribution and browsing effects of two of the largest African terrestrial mammals, the elephant and giraffe. We conducted this study within a 120‐ha (500 x 2,400 m) ForestGEO long‐term vegetation monitoring plot located at Mpala Research Center, Kenya. The plot traverses three distinct topographic habitats (“plateau,” “steep slopes,” and “valley”) with contrasting elevation, slope, soil properties, and vegetation composition. To quantify browsing damage, we focused on Acacia mellifera, a palatable tree species that occurs across the three habitat categories. Overall tree density, species richness, and diversity were highest on the steep slopes and lowest on the plateau. Acacia mellifera trees were tallest and had the lowest number of stems per tree on the steep slopes. Both elephant and giraffe avoided the steep slopes, and their activity was higher during the wet season than during the dry season. Browsing damage on Acacia mellifera was lowest on the steep slopes. Elephant browsing damage was highest in the valley, whereas giraffe browsing damage was highest on the plateau. Our findings suggest that fine‐scale habitat heterogeneity is an important factor in predicting the distribution of large herbivores and their effects on vegetation and may interact with other drivers such as edaphic variations to influence local variation in vegetation structure and composition.