Habitat Utilization of Three Sympatric Cheirogaleid Lemur Species in a Littoral Rain Forest of Southeastern Madagascar

I compared the habitat utilization in 3 sympatric species of Cheirogaleidae (Microcebus murinus [81 g], Cheirogaleus medius [183 g] and Cheirogaleus major [362 g]) in a littoral rain forest in southeastern Madagascar during 3 rainy seasons. Females of promiscuous Microcebus murinus had small home ranges and the males had large overlapping home ranges. Home ranges of family groups of monogamous Cheirogaleus medius and C. major overlapped extensively. Home ranges of all 3 species overlapped completely in the study area but home range sizes differed among species and correlate positively with body masses. Male Microcebus murinus slept in open vegetation (79%) and alone (71%), whereas female M. murinus and family group members of Cheirogaleus spp. preferred communal sleeping in tree holes. There are significant interspecific differences in the choice of sleeping sites: smaller lemurs chose smaller trees and used more sleeping sites than larger lemurs did. Species also differed significantly in the vertical dimension of forest utilization: Cheirogaleus major used the upper part of the trees, C. medius used the middle parts, and Microcebus murinus used the understory during nocturnal activities. The 3 species differed mainly in vertical habitat utilization and showed vertical stratification.     

Population Density and Home Range Size of <Emphasis Type="Italic">Indri indri</Emphasis> in a Protected Low Altitude Rain Forest

We report the results of a census of Indri indri conducted in Betampona Nature Reserve, a lowland rain forest in eastern Madagascar. In addition, we conducted a year-long study of the ranging behavior of 3 groups in the southwestern region of the reserve. We used 2 methods to calculate population density and home range size, and to provide minimum and maximum estimates. Population density of Indri indri ranged from 6.9–13.2 individuals/km² in Betampona. Mean home range size is 27 ha. The values for population density and home range size are intermediate between values for Indri indri in selectively logged and undisturbed montane rain forest. Our results suggest a relationship between habitat disturbance, population density and home range size for the species. Recent increases in habitat disturbance appear to cause an increase in population density and a decrease in home range size. The results are consistent with ones for other folivorous primate populations. Further research on habitat requirements of Indri and availability in Betampona is necessary to investigate the possibility of translocating Indri from nearby forest fragments into Betampona.     

Size and overlap of home range inCalomys musculinus (Muridae: Sigmodontinae)

Home range size and overlap ofCalomys musculinus (Thomas, 1913) was examined in relation to sex and breeding periods. The study was carried out in four 0.25 ha enclosures, in a natural pasture, between October 2002 and July 2003. The four enclosures functioned as independent populations and each was considered a replicate. The capture, mark and recapture method was used. Home range size and overlap inC. musculinus depended on sex and period. Home range size of males was always larger than that of females. Females showed a small degree of intra-sexual home range overlap during the breeding period. In general, male home ranges overlapped with females. We conclude that differences in home range size inC. musculinus is determined by sex and breeding period. Moreover, the degree of inter- and intra-sexual home range overlap during the breeding period suggests that both males and females ofC. musculinus use space differently. Females did not share their home range with other females, while males fully shared it with both sexes, and male spacing is influenced by the distribution of females. A promiscuous-polygynous mating system is suggested forC. musculinus.     

Habitat Use and Trophic Niche Overlap of Two Sympatric Colobines, Presbytis potenziani and Simias concolor, on Siberut Island, Indonesia

According to ecological theory, the concept of niche differentiation is essential to our understanding of how sympatric species can limit competition over resources. We here examine ecological niche differentiation in 2 sympatric Asian langurs, Presbytis potenziani and Simias concolor, both endemic to the Mentawai Islands off the west coast of Sumatra. We collected data (home range size, canopy use, activity budgets, diet, and niche breadth and overlap) using GPS and scan/focal animal sampling methods on 2 groups of Presbytis potenziani and 3 groups of Simias concolor living in a mixed primary rain forest in northern Siberut. Results show that home ranges of the 2 species overlapped completely and that the home range size of Presbytis potenziani was ca. 4 times larger than that of Simias concolor. Lower canopy levels (<20 m) were used more often by Simias concolor, whereas Presbytis potenziani preferred the canopy >20 m. Apart from foraging and other activities, there was little difference in overall activity budgets of the 2 species. Regarding diet, although 60% of all food species examined were used by both langur species, they shared only 3 of the 10 most commonly eaten species. Presbytis potenziani fed more selectively on fruits, whereas Simias concolor fed predominantly on leaves. Levin’s niche breadth indices revealed that the diet of Simias concolor is more general (0.34) than that of Presbytis potenziani (0.22). Based on a Pianka index of 0.32, we conclude that there is a relatively small food niche overlap between the 2 colobine species and that diet represents an important mechanism enabling their coexistence.     

Movement Patterns and Spatial Relationships Among African Forest Elephants

African forest elephants (Loxodonta cyclotis) are of immediate conservation concern, yet are understudied due to inaccessible habitats. We analyzed the home range size and overlap of six adult females. Home ranges were among the smallest for all elephant species and individuals were positioned adjacent to one another with minimal overlap.     

When species’ ranges meet: assessing differences in habitat selection between sympatric large carnivores

Differentiation in habitat selection among sympatric species may depend on niche partitioning, species interactions, selection mechanisms and scales considered. In a mountainous area in Sweden, we explored hierarchical habitat selection in Global Positioning System-collared individuals of two sympatric large carnivore species; an obligate predator, the Eurasian lynx (Lynx lynx), and a generalist predator and scavenger, the wolverine (Gulo gulo). Although the species’ fundamental niches differ widely, their ranges overlap in this area where they share a prey base and main cause of mortality. Both lynx and wolverines selected for steep and rugged terrain in mountainous birch forest and in heaths independent of scale and available habitats. However, the selection of lynx for their preferred habitats was stronger when they were forming home ranges and they selected the same habitats within their home ranges independent of home range composition. Wolverines displayed a greater variability when selecting home ranges and habitat selection also varied with home range composition. Both species selected for habitats that promote survival through limited encounters with humans, but which also are rich in prey, and selection for these habitats was accordingly stronger in winter when human activity was high and prey density was low. We suggest that the observed differences between the species result primarily from different foraging strategies, but may also depend on differences in ranging and resting behaviour, home range size, and relative density of each species. Our results support the prediction that sympatric carnivores with otherwise diverging niches can select for the same resources when sharing main sources of food and mortality.     

How Tough are Sclerophylls?

Fracture toughness was estimated for a 'least tough' path inthe leaves of woody species from three sclerophyllous plantcommunities. Most of the species from Mediterranean, tropicalheath forest and lowland tropical rain forest habitats had verytough leaves, with toughness generally 600-1300 J m^-2, whichis two to four times higher than soft-leaved tropical pioneertrees. The toughest leaf (2032 J m^-2), Parishia insignis, camefrom the canopy of the lowland rain forest. Leaves from theshaded understorey of the rain forest did not appear any lesstough than those from the canopy.Copyright 1993, 1999 AcademicPress Leaf fracture toughness, sclerophylly, Mediterranean vegetation, tropical forest     

Niche overlap and polyspecific associations among sympatric cercopithecids in the campo animal reserve,Southwestern Cameroon

The community structure and polyspecific associations found in five sympatric resident primates (Cercopithecus nictitans, C. cephus, C. pogonias, Cercocebus torquatus, andC. albigena) and a temporary visitor (Mandrillus sphinx) were studied within the Campo Animal Reserve, a tropical rain forest in southwestern Cameroon. Several ecological variables of the six species, e.g. the number of foraging groups in the study area, group size, home range size, biomass density, and individual density, were estimated by undertaking a systematic census and by other means, e.g. tracing.C. nictitans was the most abundant species in terms of its foraging groups, biomass, and individual densities. The foraging biomass varied significantly among the six species. The five resident species frequently formed polyspecific groups.M. sphinx also associated with them when it visited the area. The food items fed on by the five resident species were also checked. An index for synecological analysis revealed that the five species shared similar food niches. The five species also utilized similar foraging areas and strata, possibly depending on the availabilities of common foods. The above results cannot be explained by conventional equilibrium-competition models. For understanding the polyspecific associations, it is proposed that the primates form polyspecific foraging groups in order to optimize their foraging biomass. This idea leads to a model that can also explain certain of the grouping behaviors, such as group fission-fusion, found in large body size primates.     

Intraspecific Variation in Home Range Overlap with Habitat Quality: A Comparison among Brown Bear Populations

We developed a conceptual model of spatial organization in vertebrates based upon changes in home range overlap with habitat quality. We tested the model using estimates of annual home ranges of adult females and densities for 30 populations of brown bears (Ursus arctos) in North America. We used seasonality as a surrogate of habitat quality, measured as the coefficient of variation among monthly actual evapotranspiration values for areas in which study populations were located. We calculated home range overlap for each population as the product of the average home range size for adult females and the estimated population density of adult females. Home range size varied positively with seasonality; however, home range overlap varied with seasonality in a nonlinear manner. Areas of low and high seasonality supported brown bears with considerable home range overlap, but areas of moderate seasonality supported brown bears with low home range overlap. These results are consistent with behavioural theory predicting a nonlinear relationship between food availability and territoriality.     

Habitat associations of Sterculiaceae trees in a Bornean rain forest plot

Questions: 1. Are trees in a Bornean tropical rain forest associated with a particular habitat? 2. Does the strength of habitat association with the species‐specific optimal habitat increase with tree size? Location : A 52‐ha plot in a mixed dipterocarp forest in a heterogeneous landscape at the Lambir Hills National Park, Sarawak, East Malaysia. Methods : Ten species from the Sterculiaceae were chosen as representative of all species in the plot, on the assumption that competition among closely related species is more stringent than that among more distantly related taxa. Their habitat associations were tested using data from a 52‐ha plot by a torus‐translation test. Results : The torus‐translation test showed that eight out of the ten species examined had significant association with at least one habitat. We could not find negative species‐habitat associations for rare species, probably due to their small sample sizes. Among four species small trees were less strongly associated with habitat than large trees, implying competitive exclusion of trees in suboptimal habitats. The other four species showed the opposite pattern, possibly owing to the smaller sample size of large trees. A habitat had a maximum of three species with which it was significantly positively associated. Conclusions : For a species to survive in population equilibrium in a landscape, habitats in which ‘source’ subpopulations can be sustained without subsidy from adjacent habitats are essential. Competition is most severe among related species whose source subpopulations share the same habitat. On the evidence of source subpopulations identified by positive species‐habitat association, species‐habitat association reduces the number of confamilial competitors. Our results therefore indicate that edaphic niche specialization contributes to coexistence of species of Sterculiaceae in the plot, consistent with the expectations of equilibrium hypotheses.     

Return of Fire as a Restoration Tool: Long‐Term Effects of Burn Severity on Habitat Use by Mexican Fox Squirrels

After decades of suppression, fire is returning to forests of the western United States through wildfires and prescribed burns. These fires may aid restoration of vegetation structure and processes, which could improve conditions for wildlife species and reduce severe wildfire risk. Understanding response of wildlife species to fires is essential to forest restoration because contemporary fires may not have the same effects as historical fires. Recent fires in the Chiricahua Mountains of southeastern Arizona provided opportunity to investigate long‐term effects of burn severity on habitat selection of a native wildlife species. We surveyed burned forest for squirrel feeding sign and related vegetation characteristics to frequency of feeding sign occurrence. We used radio‐telemetry within fire‐influenced forest to determine home ranges of Mexican fox squirrels, Sciurus nayaritensis chiricahuae, and compared vegetation characteristics within home ranges to random areas available to squirrels throughout burned conifer forest. Squirrels fed in forest with open understory and closed canopy cover. Vegetation within home ranges was characterized by lower understory density, consistent with the effects of low‐severity fire, and larger trees than random locations. Our results suggest that return of low‐severity fire can help restore habitat for Mexican fox squirrels and other native wildlife species with similar habitat affiliations in forests with a historical regime of frequent, low‐severity fire. Our study contributes to an understanding of the role and impact of fire in forest ecosystems and the implications for forest restoration as fire returns to the region.     

Home range and ranging pattern in the slender loris(Loris tardigradus lydekkerianus)

The home range and ranging pattern of the slender loris (Loris tardigradus lydekkerianus) was studied for 21 months in a scrub jungle in Dindigul, Tamil Nadu, south India. Sixteen individuals were observed for a total of 2261 hours. Home ranges were measured for eight adult individuals and eight juvenile and subadult individuals. Males had significantly larger home ranges than the females, and home range size increased post-weaning. The ranging patterns involved minimal female intrasexual overlap, large male intrasexual overlap and large intersexual range overlap.     

Habitat Selection and Use of Space by Bald-Faced Sakis (Pithecia irrorata) in Southwestern Amazonia: Lessons from a Multiyear, Multigroup Study

Population density and distribution in tropical forest vertebrates are directly linked to patterns of use of space relative to habitat structure and composition. To examine how forest type may explain the ranging behavior and high variance in group density observed within the geographic range of bald-faced saki monkeys (Pithecia irrorata), we monitored habitat use of 5 neighboring focal groups of this species in southwestern Amazonia over 3 yr. To test whether sakis are unflooded (terra firme) forest specialists, we compared home range (HR) use to the corresponding availability of 4 main forest types and quantified HR size and activity budgets as a function of forest type. HR size varied from 16 to 60 ha, and saki population density at this scale (12.5 ± 6.4 SD individuals/km²) was more closely related to forest type than to group size. Although sakis were not obligate habitat specialists, groups clearly avoided bamboo forest and preferred terra firme forest. Terra firme forests were associated with small HRs, intensive use, high HR overlap, and territorial defense, all of which suggest that saki densities will be higher in areas dominated by terra firme forest where large patches of bamboo (Guadua spp.) are absent. The increased desiccation and subsequent forest fires expected in this region from the combined impacts of climate change and human land use potentially threaten the long-term viability of old-growth terra firme forest specialists such as sakis. Regional-scale conservation efforts should ensure that extensive blocks of terra firme forest are protected in areas that remain relatively free of bamboo.     

Space and habitat use of moose in southwestern Sweden

Increasingly, wildlife managers and land managers are challenged to maintain the viability of large mammal populations. Although the moose (Alces alces) is an ecologically, economically, and culturally important ungulate species found throughout most of Sweden, little is known about its ecology throughout the southern part of the country. We collected baseline ecological data on spatial and habitat use patterns in urbanized southwestern Sweden by fitting 22 adult moose (13 F, nine M) with global positioning system (GPS) radio collars. Home range size of cows did not differ among seasons (P > 0.10); however, bulls had larger home ranges during fall than all other seasons (P < 0.010). Mean home range size of males during fall and spring was larger than females during any season (P < 0.010). We used a Euclidean distance-based approach to analyze multi-scale habitat selection by moose. Moose of both sexes and during all seasons selected boreal forest and mires when establishing a home range (P < 0.10). Moose had seasonal differences in habitat selection within their home range (P 0.001), and generally selected clear-cuts and early successional forests, mature coniferous forests, and glades, but avoided agricultural areas and open water. Habitat and space use characteristics of moose in our urbanizing study area were similar to characteristics reported for moose in forest-dominated landscapes of Fennoscandia.     

Orangutan Home Range Size and Its Determinants in a Sumatran Swamp Forest

Orangutans (Pongo pygmaeus) in a Sumatran swamp forest used home ranges far larger than any described so far for the species, in spite of living at the highest density on record. Although it was difficult to estimate home range sizes, minimum reliably estimated home range sizes for adult females are ca. 850 ha, whereas subadult and adult males used ranges of at least ca. 2500 ha, and perhaps much more. Range overlap was very high: up to 16 adult females, 9 adult males and at least 15 subadult males were seen within a single 4-ha square in the center of the study area. We found no evidence for the use of seasonally distincthome ranges—commuters—, and only some subadult males may have been transients—wanderers—without a stable home range. The large size of the home ranges is attributed to the coarse grain of the habitat mosaic, with orangutans converging on parts with a high density of favored fruit trees. Orangutans at this swamp forest included a variety of habitat types within their ranges.     

Territories of male and female terrestrial salamanders: costs,benefits, and intersexual spatial associations

Summary I used a mark-recapture study to estimate home areas for 107 red-backed salamanders (Plethodon cinereus) in a natural forest habitat. Both males and females of this species defend feeding territories, but I presume that some individuals in this relatively highdensity population (approximately 2.8 salamanders per m²) are nonterritorial floaters. Although territorial salamanders exhibited greater numbers of tail autotomies, they had significantly longer relative tail lengths. This difference suggests that territorial individuals gain benefits from territorial ownership. From the observation that home area size was inversely correlated with body size, I infer that larger animals gained higher quality foraging areas. Home areas of adults were significantly more segregated intrasexually and more aggregated intersexually than would be expected from a random distribution. Furthermore, intersexual overlap of home areas was significantly greater than intrasexual home area overlap. Territorial defense of feeding areas by male and female red-backed salamanders therefore also may play a role in mating behavior.     

西双版纳石灰岩山森林植被

石灰岩山森林是组成西双版纳地区植被的主要类型之一,由于石灰岩山的特殊生境,绝大部分石灰岩山森林与非石灰岩山森林有着显著的区别。本文通过样方调查,将本区现存的石灰岩山原生植被分为３个主要的植被类型：即热带季节性雨林,热带季节性湿润林和热带山地矮树林。石灰岩山的季节性雨林是热带雨林的一个类型,仅分布于潮湿的沟谷和阴坡,森林高达３０ｍ以上,乔木层具有３层结构。根据生境和乔木层落叶树种的多寡,可将其分为湿性季节性雨林和干性季节性雨林２种类型。湿性季节性雨林以番龙眼为标志,落叶树在乔木种类和重要值上均低于１０％。干性季节性雨林以毛麻楝,轮叶戟为标志,落叶树在种类和重要值上均占１０％～３０％。本文认为,本区石灰岩山的季节性雨林在性质上与非石灰岩季节性雨林相同,尽管二者在群落的区系组成上有所差异。热带季节性湿润林主要分布于山坡中部,森林高度通常为２０～２５ｍ,乔木层具有２层结构。根据落叶树种的多寡可将其分为热带季节性常绿湿润林和热带季节性半常绿湿润林等２个类型。季节性常绿湿润林高约２０ｍ,森林常绿或有少量落叶树种,以多脉桂花,易武栎及尖叶闭花木为标志和优势。季节性半常绿湿润林高２０～２５ｍ,落叶树在乔木种类上占３０％～６?     

Dual mycorrhizal colonization of forest-dominating tropical trees and the mycorrhizal status of non-dominant tree and liana species

The contribution of mycorrhizal associations to maintaining tree diversity patterns in tropical rain forests is poorly known. Many tropical monodominant trees form ectomycorrhizal (EM) associations, and there is evidence that the EM mutualism contributes to the maintenance of monodominance. It is assumed that most other tropical tree species form arbuscular mycorrhizal (AM) associations, and while many mycorrhizal surveys have been done, the mycorrhizal status of numerous tropical tree taxa remains undocumented. In this study, we tested the assumption that most tropical trees form AM associations by sampling root vouchers from tree and liana species in monodominant Dicymbe corymbosa forest and an adjacent mixed rain forest in Guyana. Roots were assessed for the presence/absence of AM and EM structures. Of the 142 species of trees and lianas surveyed, three tree species (the monodominant D. corymbosa, the grove-forming D. altsonii, and the non-dominant Aldina insignis) were EM, 137 were exclusively AM, and two were non-mycorrhizal. Both EM and AM structures were observed in D. corymbosa and D. altsonii. These results provide empirical data supporting the assumption that most tropical trees form AM associations for this region in the Guiana Shield and provide the first report of dual EM/AM colonization in Dicymbe species. Dual colonization of the Dicymbe species should be further explored to determine if this ability contributes to the establishment and maintenance of site dominance. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Home range and ranging behaviour of Bornean elephant (Elephas maximus borneensis) females

Background

Home range is defined as the extent and location of the area covered annually by a wild animal in its natural habitat. Studies of African and Indian elephants in landscapes of largely open habitats have indicated that the sizes of the home range are determined not only by the food supplies and seasonal changes, but also by numerous other factors including availability of water sources, habitat loss and the existence of man-made barriers. The home range size for the Bornean elephant had never been investigated before.

Methodology/Principal Findings

The first satellite tracking program to investigate the movement of wild Bornean elephants in Sabah was initiated in 2005. Five adult female elephants were immobilized and neck collars were fitted with tracking devices. The sizes of their home range and movement patterns were determined using location data gathered from a satellite tracking system and analyzed by using the Minimum Convex Polygon and Harmonic Mean methods. Home range size was estimated to be 250 to 400 km² in a non-fragmented forest and 600 km² in a fragmented forest. The ranging behavior was influenced by the size of the natural forest habitat and the availability of permanent water sources. The movement pattern was influenced by human disturbance and the need to move from one feeding site to another.

Conclusions/Significance

Home range and movement rate were influenced by the degree of habitat fragmentation. Once habitat was cleared or converted, the availability of food plants and water sources were reduced, forcing the elephants to travel to adjacent forest areas. Therefore movement rate in fragmented forest was higher than in the non-fragmented forest. Finally, in fragmented habitat human and elephant conflict occurrences were likely to be higher, due to increased movement bringing elephants into contact more often with humans.     

Microsatellite markers in soil‐feeding termites (Cubitermes subarquatus,Isoptera, Termitidae,Termitinae)

Seven microsatellite markers were isolated from Cubitermes subarquatus belonging to the soil‐feeding termite trophic group that plays a key role in tropical rain forests. A variability study performed by using a population of C. subarquatus (n = 73) sampled in the La Lopé forest reserve (Gabon) from 42 nests revealed from 4 to 12 alleles per locus and an heterozygosity from 0.28 to 0.84. Tests for cross‐species amplification realized in the sympatric C. intercalatus and in eight other sympatric termite genera indicated a wider application of the primers isolated from Cubitermes in soil‐feeding termites.