Changes in forest fragment sizes and primate population trends along the River Tana floodplain, Kenya

The Tana River forest patches significantly decreased in total area by 1875 ha (34.5%), from 5439 to 3564 ha between 1979 and 2000. The area covered by forests outside the Tana River Primate National Reserve declined by 1246 ha (38%) from 3283 to 2037 ha. This loss was higher than that inside the reserve, where total forest area reduced by 629 ha (29%) from 2156 to 1527 ha. The numbers of Tana River red colobus (Procolobus rufomitratus) and Tana crested mangabey (Cercocebus galeritus galeritus) groups were significantly correlated with forest sizes suggesting that both red colobus and crested mangabeys are likely to be affected by forest loss and fragmentation. However, comparison of the 1974/75 and 2001 census data did not reveal any significant change in the number of groups of either the red colobus or crested mangabey. The two endangered primates may have developed strategies to cope with a shrinking habitat.     

Ranging behavior of the François’ langur (<Emphasis Type="Italic">Trachypithecus francoisi</Emphasis>) in the Fusui Nature Reserve,China

Data on activity budgets and ranging patterns were collected from March to December 2001 for one group of François’ langurs (Trachypithecus francoisi) inhabiting a forested part of the Fusui Nature Reserve, Guangxi province, China. Our results indicate that the total size of the home range of the study group during the study period was 19 ha. The majority of their activities (52%) occurred within a small area, 22%, of their home range, and was concentrated in or near quadrats containing their sleeping sites, which may reduce the time and energetic cost of travel. The extent of the ranging behavior varied between months, with the smallest, 7 ha, recorded in July and the largest, 13.5 ha, in November. There was no significant difference between seasons. The monthly mean daily path lengths varied from 341 to 577 m. The daily path lengths showed significant seasonal changes: the path lengths were longer during the dry season than in the rainy season, which may be related to the scarcity of preferred food resources during the dry season.     

Tana River Mangabey Use of Nonforest Areas: Functional Connectivity in a Fragmented Landscape in Kenya

Habitat loss and fragmentation is a serious threat to biodiversity. Fragment isolation can be reduced if fragments are connected, either structurally through habitat corridors or functionally if the species can move through the surrounding matrix. One-way to evaluate landscape connectivity is to observe natural movements of animals within fragmented landscapes. The Tana River mangabey (Cercocebus galeritus) is an endangered monkey endemic to fragmented forests along the lower Tana River in Kenya, and who has been observed to move through matrix between fragments. One mangabey group moved through 1 km of matrix, while another group moved through two areas of matrix. I collected behavioral and ranging data on the latter group to describe its behavior and time spent in the matrix. Utilizing data from belt transects in the matrix and forest fragments, I characterized the vegetation structure of the matrix and compared it to the forests included in each group's home range. The group spent the majority of their time eating while in the matrix, and spent an average 36.4 min in one matrix area and 100 min in the other. The matrix is generally characterized by the highest measures for a nonforest attribute and the lowest measures for forest attributes. These results suggest that forest fragments are functionally, but not structurally, connected for the mangabey; a landscape approach to conservation, therefore, should be taken for the lower Tana River. Research investigating the limitations of the mangabey's ability to use the matrix is needed.     

Home range and activity patterns of male red deer (Cervus elaphus L.) in the alps

Summary From 1978 to 1981 in the Bavarian Alps (Southern West Germany) the home range and activity patterns of nine male red deer have been studied using radio-telemetry. The home range patterns definetely change with age. Younger stags first follow the patterns of their mothers, then often emigrate from these home ranges and establish new ones elsewhere. Except for the change in range at about 2^1/2 years of age, these patterns seem to be very constant in both spatial as well as seasonal position and the size of the home ranges. Winter and rutting ranges are relatively small, averaging 113 ha and 134 ha, respectively, whereas the mean size of the home ranges used from spring to autumn amounts to some 386 ha. Just as do the home range patterns, so also do activity patterns exhibit a marked annual cycle. The daily sum total of activity varies from about 9 h in winter to some 15 h in summer. The daily distribution of activity reveals a typical bimodal 24-h rhythm which in the course of the year also shows modifications according to the seasonally varying LD-ratio. In the discussion, earlier results on female red deer are compared to those of this study. Notable differences between sexes occur in the home range patterns and the annual cycle of daily activity.     

Ranging Patterns of Two Syntopic Howler Monkey Species (Alouatta guariba and A. caraya) in Northeastern Argentina

To avoid competition, ecologically similar and closely related species tend to differ in their patterns of habitat use when they live in sympatry. We compared ranging patterns of brown howler (Alouatta guariba) and black and gold howler (A. caraya) monkeys living syntopically, i.e., co-occurring and overlapping their ranges in the same habitat within the zone of sympatry, in the Atlantic Forest of northeastern Argentina with the objective of evaluating whether their use of space contributes to the avoidance of interspecific competition for food resources. During 12 mo we collected data on the ranging behavior of 2 groups of each howler species. We analyzed annual and seasonal daily path lengths and movement rates, home range size, use and overlap, habitat and vertical strata use, and intergroup encounters. Black and gold howlers traveled farther and faster during the time of relative food abundance (abundant season) than during the time of relative food shortage (lean season), and their movement rates were affected by group identity and increased with the proportion of fruits in the diet. Brown howlers’ traveling patterns were not affected by any of these factors. Home ranges for both species (95% fixed kernel; brown howlers: 31–70 ha, black-and-gold howlers: 17–112 ha) were among the largest recorded for Alouatta. For both species, core areas (50% fixed kernel) were larger for larger versus smaller groups, and decreased in the lean season compared to the abundant season. Both species showed similar patterns of habitat use, except for a slight vertical stratification. Groups of different species overlapped their ranging areas consistently more and responded to one another less aggressively during encounters than groups of the same species, suggesting that interspecific spatial niche separation for these two syntopic species is not occurring. The vertical stratification, as well as a day-to-day avoidance strategy, may be the only responses of species to one another that could reduce the potentially high levels of competition for food suggested by their elevated trophic niche overlap. A high degree of niche overlap may explain the parapatric distribution of howlers and other closely related and ecologically similar species of primates.     

Home-Range Use and Activity Patterns of the Red Langur (Presbytis rubicunda) in Sabangau Tropical Peat-Swamp Forest, Central Kalimantan, Indonesian Borneo

Knowledge of a species’ ranging patterns is vital for understanding its behavioral ecology and vulnerability to extinction. Given the abundance and even distribution of leaves in forested habitats, folivorous primates generally spend less time feeding; more time resting; have shorter day ranges; and require smaller home ranges than frugivorous primates. To test the influence of frugivory on ranging behavior, we established the activity budget and home-range size and use in a highly frugivorous population of the Borneo-endemic colobine, Presbytis rubicunda, within Sabangau tropical peat-swamp forest, Central Kalimantan, and examined relationships between fruit availability and ranging patterns. We collected 6848 GPS locations and 10,702 instantaneous focal behavioral scans on a single group between January and December 2011. The group had the largest home-range size recorded in genus Presbytis (kernel density estimates: mean = 108.3 ± SD 3.8 ha, N = 4 bandwidths). The annual activity budget comprised 48 ± SD 4.0% resting; 29.3 ± SD 3.9% feeding, 14.2 ± SD 2.5% traveling, and 0.4 ± SD 0.4% social behaviors. Mean monthly day-range length was the highest recorded for any folivorous primate (1645 ± SD 220.5 m/d). No significant relationships existed between ranging variables and fruit availability, and ranging behaviors did not vary significantly across seasons, potentially owing to low fluctuations in fruit availability. Our results suggest that colobine monkeys maintain larger than average ranges when high-quality food resources are available. Their extensive range requirements imply that protecting large, contiguous tracts of habitat is crucial in future conservation planning for Presbytis rubicunda.     

Seasonally Consistent Small Home Range and Long Ranging Distance in <Emphasis Type="Italic">Presbytis rubicunda</Emphasis> in Danum Valley,Borneo

Seasonal fluctuation in food availability is a universal problem for wild animals. One common response to dietary changes is to modify ranging patterns. We studied the ranging pattern of one group (8–12 individuals) of red leaf monkeys (Presbytis rubicunda) in the lowland dipterocarp forest of Danum Valley, Borneo from December 2006 to December 2008. The seasonal availability of fruits varies significantly in this forest because of mast fruiting. We tested the hypothesis that changes in ranging pattern are linked with seasonal changes in diet in this species. We recorded activity, foods eaten, and location every 10 min from around 06:00 until 16:00 h, 5–10 days/mo. The home range size was 21.4 ha over the 25-mo study (95% kernel contour). There were no statistically significant relationships between feeding times on the four major nonexclusive dietary components (all species of seeds, all species of young leaves, young leaves of Spatholobus macropterus, and other species of young leaves) and either the home range (95% kernel contour) or the core area (50% kernel contour). The areas used in the seed-eating and non-seed-eating seasons overlapped to a large extent. The daily path length was 1160 ± 340 m (mean ± SD, range: 550–2140 m). Neither daily path length nor monthly mean travel rate was significantly related to feeding time on any of the four major dietary components. The group’s ranging patterns may be related to the unusual fallback strategy of this population, which depends on the young leaves of an abundant liana (S. macropterus), which are available in small patches. The monkeys need only a small home range because of the high abundance of these leaves. However, they range a relatively long distance because the patches of S. macropterus are easily depleted; thus the ranging distance does not decrease in non-seed-eating periods.     

Demography, life history and migrations in a Mexican mantled howler group in a rainforest fragment

This paper represents the results of a long-term study (1996-2003) on the demographic changes over time of a Mexican mantled howler (Alouatta palliata mexicana) group in a rainforest fragment (40 ha) in Los Tuxtlas, Mexico, with a follow-up census 3 years later (2006). In addition to demographic and life history parameters, we describe six dispersal events. Our results suggest that this group has been expanding during the study period, growing from six to 12 individuals, with an annual average intrinsic growth rate of 0.07, an infant survivorship of 67%, and an average immature to female ratio of 0.90. This increase in size is probably related to the high food availability in their home range. However, fragment isolation may be negatively affecting the dispersal patterns typical of the species, which could result in a loss of genetic variability over time.     

Diet and habitat overlap in two sympatric primate species, the Tana crested mangabey Cercocebus galeritus and yellow baboon Papio cynocephalus

Diet and habitat overlap was studied in two sympatric primate species sharing two neighbouring patches of fragmented gallery forest in Tana River, Kenya. Systematic data on feeding and ranging behaviour was collected on one group each of the Tana crested mangabey Cercocebus galeritus and yellow baboon Papio cynocephalus between August 1992 and February 1993. When rainfall was low and fruit resources scarce, yellow baboons spent most of their foraging time in the open woodlands while mangabeys foraged within the forest. At this period, diet and habitat overlaps between the two species were low. As rainfall increased, followed by a gradual rise in fruit availability, yellow baboons shifted their foraging range and both species became confined to the forest habitat. Consequently, both diet and habitat overlaps increased, peaking at the end of the rainy season. Mangabeys showed a reduced within-group dispersal and also spent significantly less time foraging in a given forest patch when yellow baboons were also present within the same forest patch.
Increased habitat and diet overlaps during the wet season need not have resulted in increased interspecific competition for food because at this period, fruits were readily available in the forest.     

Ranging behavior of eastern hoolock gibbon (Hoolock leuconedys) in a northern montane forest in Gaoligongshan,Yunnan, China

Generally, food abundance and distribution exert important influence on primate ranging behavior. Hoolock gibbons (genus Hoolock) live in lowland and montane forests in India, Bangladesh, Myanmar and China. All information about hoolock gibbons comes from studies on western hoolock gibbons (Hoolock hoolock) living in lowland forest. Between August 2010 and September 2011, we studied the ranging behavior of one habituated group of eastern hoolock gibbon (H. leuconedys) living in a seasonal montane forest in Gaoligongshan, Yunnan, China. Results show that the study group did not increase foraging effort, calculated in this study as the daily path length, when fruit was less available. Instead, the gibbons fed more on leaves and decreased traveling to conserve energy. They relied heavily on a single food species in most study months which was patchily distributed within their total (14-month) home range, and during most months they used only a small portion of their total home range. In order to find enough food, the group shifted its monthly home range according to the seasonal availability of food species. To satisfy their annual food requirements, they occupied a total home range of 93 ha. The absence of neighboring groups of gibbons and the presence of tsaoko cardamom (Amomum tsaoko) plantations may also have influenced the ranging behavior of the group. Further long-term studies of neighboring groups living in intact forests are required to assess these effects.     

Ranging Behavior of Proboscis Monkeys (Nasalis larvatus) in the Lower Kinabatangan, Northern Borneo

I studied the ranging behavior of proboscis monkeys (Nasalis larvatus) at two sites in the Lower Kinabatangan Region of northern Borneo. I collected data on ranging behavior via scan sampling during group follows. Groups of Nasalis larvatus had ranges overlapping those of other groups in each area. I observed no territorial behavior. Groups of Nasalis larvatus occasionally swam across the Kinabatangan River, and frequently across its tributaries. The home range size of a focal one-male group (SU1) was 220.5 ha. The group traveled farther on days when the proportion of young leaves in the diet was higher. In addition, SU1 used particular areas when they fed on flowers and fruits. Apparently, rainfall and phenology did not influence ranging patterns.     

Tana river red colobus and crested mangabey: Results of recent censuses

Censuses of the Tana River red colobus (Colobus badius rufomitratus) and crested mangabey (Cercocebus galeritus galeritus), primate species endemic to riverine forests of the lower Tana River in eastern Kenya, showed significant population declines for both species between the mid-1970s and 1980s. Red colobus declined in terms of group size and number of groups per forest; the mangabey population declined only in numbers of groups per forest. There was no significant change in mean group age/sex composition between the two time periods for either species. Differences in the feeding and ranging ecology of the two species may explain why the mangabey population suffered a less severe decline than the red colobus. Similarities in census results over 3 years in the late 1980s suggest that the primate populations are no longer decreasing.     

Ranging behavior of woolly spider monkeys,or muriquis,Brachyteles arachnoides

During a 14-month study of one group of woolly spider monkeys, or muriquis (Brachyteles arachnoides),at Fazenda Montes Claros, M. G., Brazil, the group used a home range of 168 ha. Day-range lengths averaged 1283 m and were longer in the wet season than in the dry season. An analysis of travel rates indicated that the group traveled faster on those days when they traveled farther. The availability of large patches of preferred food sources appears to affect daily movement patterns. Intraspecific comparisons, in addition to an apparent expansion of the study group’s home range as their group size has increased, suggest the importance of group size to muriqui range size. Interspecific comparisons between muriquis and sympatric brown howler monkeys suggest that locomotor adaptations are important to understanding species differences in ranging behavior.     

Tree mortality due to an El Niño flood along the lower Tana River, Kenya

This study investigated forest tree mortality as a result of the extremely strong 1997–1998 El Niño flood in Tana River, Kenya, directly tested how mortality varied in relation to tree species and diameter at breast height (DBH), and indirectly tested how mortality varied in relation to floodwater depth. The study forest was under 2 m of water for approximately 71 days, from December 1997 until February 1998. Twenty-five liana, subcanopy tree, and canopy tree species were selected based on their importance in the diet of the Tana River mangabey ( Cercocebus galeritus Peters), a critically endangered primate endemic to the Tana River. Reproductive-sized individuals of these species were enumerated in 16.25 ha. I also enumerated trees killed by the El Niño flood, recorded their location in the forest, and measured their DBH. Ninety-two trees in fifteen species were killed by the flood. There were significant differences in mortality by species and by 0.25 ha quadrat. There were negative correlations between number of dead and DBH, number of dead and distance from the river, and per cent of quadrat killed and distance from the river. There appear to have been few long-term consequences of the El Niño flood in the forest or for the mangabeys.     

Ecological Correlates of Ranging Behavior in Bearded Sakis (Chiropotes sagulatus) in a Continuous Forest in Guyana

Group size and the distribution and quality of food resources are among the most important determinants of primate ranging behavior. In this study, I use the framework of the ecological constraints model to assess correlates of range size of a free-ranging group of bearded sakis (Chiropotes sagulatus). Bearded sakis are among the widest ranging neotropical primates, yet the lack of data from continuous forest populations has made understanding the factors influencing such large ranges difficult. I collected data on ranging behavior and diet during 44 full-day follows over 15 mo. The focal group used a home range of ca. 1000 ha and had daily path lengths of 2.8–6.5 km (mean?=?4.0 km). Daily path length did not significantly correlate with group size, patch quality, food availability, or the spatial distribution of feeding trees. Monthly home range size significantly positively correlated with group size and patch quality. The focal group had significantly shorter paths when ripe fruit consumption was higher and had more diverse diets, visited more food patches, and used larger monthly home ranges when they consumed a higher percentage of seeds. The results of this study, combined with other recent studies of Chiropotes in continuous forest, suggest that large home ranges (approaching 1000 ha) are characteristic of the genus. Although range size may be related to group size and food patch size, I suggest nutrient mixing and the need to balance the effects of seed secondary compounds as additional explanations for the large ranges of bearded sakis.     

Ammonia volatilization from a seasonally and spatially variable grazed grassland: Yellowstone National Park

We measured ammonia volatilization at three topographic positions(hilltop, mid-slope, slope-bottom) on three grassland landscapes at threetimes during 1995 (April, May, July) on the northern winter range ofYellowstone National Park that supports large herds of native ungulates.Percent ammonia-N lost from all sites during the study ranged 1–24%of urea-N applied. Volatilization among sites was negatively related tosoil cation-exchange capacity (r = –0.85) and rates were highest inJuly. We used the relationship between soil CEC and percent Nvolatilized from urea-amended plots to estimate annual ammonia-Nvolatilization from 5 sites for which annual ungulate urine inputs werepreviously determined (Frank et al. 1994). Estimated mean annualammonia-N volatilized from those sites was 1.4 kg/ha/yr, which wasless than a previously reported regional atmospheric deposition rate (2kg/ha/yr; Swank 1984). Results indicate the need to understand theinteraction between (1) spatially heterogeneous patterns of soilprocesses, and 2) nonuniform patterns of ungulate use of landscapes todetermine rates of ecosystem-level N-gaseous loss. Findings alsosuggest that ammonia-N volatilized from urine patches should not leadto a decline in soil N in this ecosystem.     

Effects of food and topography on ranging behavior of black crested gibbon (Nomascus concolor jingdongensis) in Wuliang Mountain, Yunnan, China

We studied the ranging behavior of a habituated group of black crested gibbons (Nomascus concolor jingdongensis) in a high, seasonal habitat on Mt. Wuliang, central Yunnan, China, between March 2005 and April 2006. Our results indicated that the total home range size for the study group was 129 ha, or 151 ha if the lacunae within the borders in which gibbons were not observed were included. This is a much bigger range size than that of other gibbon species. However, 69.7% of their activities occurred within 29 ha. The intensity of quadrant use was significantly correlated with the distribution of important food patches. The mean yearly daily path length was 1,391 m. Gibbons traveled farther when they spent more time feeding on fruit. To avoid often passing through ridges with little food, gibbons usually stayed in the same valley for successive days, and then moved on to another valley for another several days, which resulted in a concentrated ranging pattern.     

Inter‐group variability in seed dispersal by white‐handed gibbons in mosaic forest

Seed dispersers, like white‐handed gibbons (Hylobates lar), can display wide inter‐group variability in response to distribution and abundance of resources in their habitat. In different home ranges, they can modify their movement patterns along with the shape and scale of seed shadow produced. However, the effect of inter‐group variability on the destination of dispersed seeds is still poorly explained. In this study, we evaluate how seed dispersal patterns of this arboreal territorial frugivore varies between two neighboring groups, one inhabiting high quality evergreen forest and one inhabiting low quality mosaic forest. We predicted a difference in seed dispersal distance between the two groups (longer in the poor quality forest). We hypothesized that this difference would be explained by differences in home range size, daily path length, and ranging tortuosity. After 6 months of data collection, the evergreen group had a smaller home range (12.4 ha) than the mosaic group (20.9 ha), significantly longer daily path lengths (1507 m vs. 1114 m respectively) and greater tortuosity (39.1 vs. 16.1 respectively). Using gut passage times and displacement rates, we estimated the median seed dispersal distance as 163 m for the evergreen group (high quality forest) and of 116 m for the mosaic group (low quality forest). This contradiction with our initial prediction can be explained in term of social context, resource distribution, and habitat quality. Our results indicate that gibbons are dispersers of seeds between habitats and that dispersal distances provided by gibbons are influenced by a range of factors, including habitat and social context.     

Territorial shift in the yellow-handed titi monkey (Callicebus torquatus)

In this study, the ranging pattern of a single group of monogamous and territorial Callicebus torquatus was recorded over a 7-year period from 1974 to 1980. Data on ranging pattern were recorded by direct observation; daily movement patterns were plotted on an accurate, scaled map of the territory. Data were obtained during 1–3-month studies each year from 1974 to 1978 and in 1980, as well as during a 12-month study in 1979-1980. These studies show that the exclusive territory maintained by the group was not spatially stable over the 7-year period. The group gradually moved its territory to the northeast, to the extent that the territory used in 1980 was completely noncoincident with the territory used in 1974 by the same group. Analysis of the ranging pattern from the 12-month study indicates that the group did not exhibit seasonal preferences for different parts of its range. Seasonal ranging patterns, therefore, are not likely to account for the observed territorial shift. It is suggested that territorial shifting may be related to the need for monogamous groups to find new territories for their offspring.