Daily Travel Distances of Unhabituated Grauer’s Gorillas (Gorilla beringei graueri) in a Low Elevation Forest

2021 ◽  
Vol 92 (2) ◽  
pp. 112-125
Author(s):  
Yntze van der Hoek ◽  
Escobar Binyinyi ◽  
Urbain Ngobobo ◽  
Tara S. Stoinski ◽  
Damien Caillaud
Keyword(s):  
Temporal Variation ◽  
Temporal Patterns ◽  
Space Use ◽  
Wet Season ◽  
Conservation Area ◽  
Gorilla Beringei ◽  
Republic Of The Congo ◽  
Lowland Forests ◽  
Travel Distances ◽  
Daily Travel

To accurately determine the space use of animals, we need to follow animal movements over prolonged periods, which is especially challenging for the critically endangered Grauer’s gorillas (<i>Gorilla beringei graueri</i>) in eastern Democratic Republic of the Congo (DRC). As a consequence, we know little about Grauer’s gorillas, particularly from the lower elevational parts of their range. Between 2016 and 2018, we tracked unhabituated Grauer’s gorillas in lowland forests (500–1,000 m a.s.l.), at the community-managed Nkuba Conservation Area in Nord Kivu (DRC) to provide estimates of daily travel distances (DTD), daily displacement distances (DDD), and the linearity of recorded paths expressed as the Linearity Index (LI): DDD/DTD. We found an average DTD of ∼1.3 km (range 0.05–5.0 km), with temporal variation among monthly averages; specifically, an increase in travel distance over the June–August dry season resulting in peak travel distances at the beginning of the September–December wet season. Daily displacements showed similar temporal variation, which resulted in a lack of obvious temporal patterns in LI. We conclude that the movement patterns of Grauer’s gorillas in lowland forests, which are characterized by larger DTD than those of Grauer’s gorillas that inhabit highland habitats, show similarity to travel distances of other predominantly frugivorous gorillas. Moreover, the observed temporal patterns in space use may be tentatively linked to temporal changes in fruit availability or consumption. These observations have consequences for our understanding of the ecological role that Grauer’s gorillas play and provide baseline data to estimate current and future distributions, abundances, and carrying capacities of this highly threatened animal.

scholarly journals Diet of Grauer’s Gorillas (Gorilla beringei graueri) in a Low-Elevation Forest

2021 ◽  
pp. 1-12
Author(s):  
Yntze van der Hoek ◽  
Wadika Dumbo Pazo ◽  
Escobar Binyinyi ◽  
Urbain Ngobobo ◽  
Tara S. Stoinski ◽  
...  
Keyword(s):  
National Park ◽  
Wet Season ◽  
Lowland Forest ◽  
Conservation Area ◽  
Plant Parts ◽  
Food Items ◽  
Community Based Conservation ◽  
Lower Elevation ◽  
Gorilla Beringei ◽  
Republic Of The Congo

Although the vast majority of critically endangered Grauer’s gorillas (<i>Gorilla beringei graueri</i>) inhabit low-elevation rain forests, current insights into this ape’s life history and ecology stem predominantly from 2 small populations ranging in highland habitats. Here, we provide an initial and non-exhaustive overview of food items of Grauer’s gorillas in the Nkuba Conservation Area (NCA), a lower-elevation (500–1,500 m) forest located between Kahuzi-Biega National Park and Maiko National Park in the Democratic Republic of the Congo. Community-based conservation efforts at the NCA aim to protect a population of unhabituated Grauer’s gorillas, which we have studied since 2014. Between 2014 and 2020, we simultaneously tracked 1–3 gorilla groups and recorded a total of 10,514 feeding signs on at least 100 plant species, ants, termites, and fungi. Vegetative plant parts (plant stems, leaves, pith, bark, and roots), especially of Marantaceae and Fabaceae, made up close to 90% of recorded feeding signs, with fruit accounting for most of the remainder and a small (&#x3c;1%) number of feeding signs on invertebrates and fungi. We found that the most frequently recorded food items were consumed year-round, though fruit intake seems to peak in the September-December wet season, possibly reflecting patterns in fruit phenology. The diet of Grauer’s gorillas in the NCA differed from that of Grauer’s gorillas in highland habitat and instead showed similarities with Grauer’s gorillas at the lowland forest of Itebero and with western lowland gorillas (<i>G. gorilla</i>), which live under ecologically comparable conditions.

scholarly journals Better together? How intergroup associations affect energy balance and feeding behavior in wild bonobos

2020 ◽  
Vol 75 (1) ◽  
Author(s):  
Stefano Lucchesi ◽  
Leveda Cheng ◽  
Tobias Deschner ◽  
Roger Mundry ◽  
Erin G. Wessling ◽  
...  
Keyword(s):  
Energy Balance ◽  
Feeding Behavior ◽  
Energetic Costs ◽  
Neighboring Group ◽  
Group Competition ◽  
Republic Of The Congo ◽  
Group Members ◽  
Intergroup Encounters ◽  
Time Spent Feeding ◽  
Travel Distances

Abstract When the benefits of interacting with out-group members exceed the associated costs, social groups may be expected to be tolerant towards each other. However, in many species exhibiting intergroup tolerance, the nature of benefits gained from intergroup encounters remains unclear. We investigated the potential costs and benefits associated with intergroup associations in bonobos, a species with varying degrees of intergroup tolerance, by testing whether these associations conferred energetic benefits to participants under different socioecological contexts and whether the consequences of these associations substantially differed from within-group competition. We used measures of socioecological factors (fruit abundance and group size), feeding and ranging behaviors, and a physiological marker of energy balance (urinary c-peptide of insulin) collected over a 19-month period from two neighboring wild communities in the Kokolopori Bonobo Reserve, Democratic Republic of the Congo. We found that intergroup associations were not related to individuals’ energy balance, but they were related to variations in individuals’ ranging and feeding behavior. Specifically, bonobos traveled longer distances, visited larger fruit patches, and increased the time spent feeding on fruits on days they associated with the neighboring group. These adaptations in feeding behavior may be strategies to offset the energetic costs of increased travel distances. In the absence of obvious energetic benefits and with clear strategies employed to offset energetic costs, it is likely that intergroup associations in bonobos provide benefits unrelated to energy acquisition, such as social benefits. Our study sheds light on the potential incentives promoting social networks to extend beyond and across groups in a tolerant species. Significance statement Intergroup encounters can be energetically costly due to increased competition over resources. Yet, some species associate with out-group individuals for extended periods of time when the benefits of participating in these associations exceed the potential costs. Bonobos, a species exhibiting intergroup tolerance, modified their feeding behavior during intergroup associations by feeding on larger fruit patches and increasing their time spent feeding on fruits, likely to offset energetic costs of increased travel distances. As results, individuals’ energy balance was not related with intergroup associations. The employment of such strategies in addition to the absence of clear energetic benefits suggests that intergroup associations in bonobos provide social rather than ecological benefits.

scholarly journals Stalked barnacle (Pollicipes pollicipes) harvesting in the Berlengas Nature Reserve, Portugal: temporal variation and validation of logbook data

2009 ◽  
Vol 67 (1) ◽  
pp. 19-25 ◽  
Author(s):  
David Jacinto ◽  
Teresa Cruz ◽  
Teresa Silva ◽  
João J. Castro
Keyword(s):  
Temporal Variation ◽  
Nature Reserve ◽  
Marine Protected Area ◽  
Temporal Patterns ◽  
Fishing Effort ◽  
Tidal Range ◽  
Systematic Bias ◽  
Pollicipes Pollicipes ◽  
Specific Regulation ◽  
Logbook Data

Abstract Jacinto, D., Cruz, T., Silva, T., and Castro, J. J. 2010. Stalked barnacle (Pollicipes pollicipes) harvesting in the Berlengas Nature Reserve, Portugal: temporal variation and validation of logbook data. – ICES Journal of Marine Science, 67: 19–25. Stalked barnacle (Pollicipes pollicipes) exploitation at the Berlengas Nature Reserve, Portugal, by professional harvesters has been subject to specific regulation since 2000. The only available information on barnacle exploitation there comes from catch reports (logbooks) provided by the harvesters. We evaluated the quality of the logbook information, described the temporal patterns of P. pollicipes fishing effort from 2000 to 2006 based on the logbook data, and modelled the daily fishing effort in relation to variability in oceanographic conditions. Results suggest different levels of reliability for the information contained in the logbooks: (i) information on the date of harvest seems to be reliable because 83% of the observed harvest dates were also declared; (ii) information on the quantity harvested shows a large discrepancy (mean = 31.8%) between declared and observed amounts, but we believe it can be used to analyse temporal patterns of exploitation, because there was no systematic bias (under- and overreporting was to the same extent). The total quantity of barnacles harvested between 2000 and 2006 (∼16 t year−1) was closely related to the effort applied. Daily harvesting effort was considered a function of two predictive variables (significant wave height and tidal range) and of their interaction. Neither the harvesting activity nor the resource itself seems to be at risk of collapse if such levels of pressure are maintained, but efforts should be made to increase surveillance and monitoring within the marine protected area.

scholarly journals Long-term spatial and temporal variation of CO<sub>2</sub> partial pressure in the Yellow River, China

2015 ◽  
Vol 12 (4) ◽  
pp. 921-932 ◽  
Author(s):  
L. Ran ◽  
X. X. Lu ◽  
J. E. Richey ◽  
H. Sun ◽  
J. Han ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Temporal Variation ◽  
Yellow River ◽  
Dilution Effect ◽  
High Pco2 ◽  
Spatial And Temporal Variation ◽  
The Yellow River ◽  
Wet Season ◽  
Co2 Partial Pressure ◽  
River Waters

Abstract. Carbon transport in river systems is an important component of the global carbon cycle. Most rivers of the world act as atmospheric CO2 sources due to high riverine CO2 partial pressure (pCO2). By determining the pCO2 from alkalinity and pH, we investigated its spatial and temporal variation in the Yellow River watershed using historical water chemistry records (1950s–1984) and recent sampling along the mainstem (2011–2012). Except the headwater region where the pCO2 was lower than the atmospheric equilibrium (i.e. 380 μatm), river waters in the remaining watershed were supersaturated with CO2. The average pCO2 for the watershed was estimated at 2810 ± 1985 μatm, which is 7-fold the atmospheric equilibrium. As a result of severe soil erosion and dry climate, waters from the Loess Plateau in the middle reaches had higher pCO2 than that from the upper and lower reaches. From a seasonal perspective, the pCO2 varied from about 200 μatm to > 30 000 μatm with higher pCO2 usually occurring in the dry season and lower pCO2 in the wet season (at 73% of the sampling sites), suggesting the dilution effect of water. While the pCO2 responded exponentially to total suspended solids (TSS) export when the TSS concentration was less than 100 kg m−3, it decreased slightly and remained stable if the TSS concentration exceeded 100 kg m−3. This stable pCO2 is largely due to gully erosion that mobilizes subsoils characterized by low organic carbon for decomposition. In addition, human activities have changed the pCO2 dynamics. Particularly, flow regulation by dams can diversely affect the temporal changes of pCO2, depending on the physiochemical properties of the regulated waters and adopted operation scheme. Given the high pCO2 in the Yellow River waters, large potential for CO2 evasion is expected and warrants further investigation.

Sexual and environmental variation in the space requirements of the Critically Endangered geometric tortoise, Psammobates geometricus

2012 ◽  
Vol 33 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Margaretha Hofmeyr ◽  
Ulric van Bloemestein ◽  
Brian Henen ◽  
Craig Weatherby
Keyword(s):  
Home Range ◽  
Habitat Degradation ◽  
Space Use ◽  
Home Range Size ◽  
Home Ranges ◽  
Convex Polygons ◽  
Wet Season ◽  
Mating Opportunities ◽  
Space Requirements ◽  
Nesting Season

Psammobates geometricus has a limited distribution in the southwestern Cape, South Africa, where it occurs in small habitat fragments separated by agricultural and urban developments. Space use and its determining factors thus represent critical information for the effective conservation of this species. We used radiotelemetry and thread-trailing to study the movement patterns and space use of geometric tortoises over an annual cycle, and estimated home ranges with minimum convex polygons and fixed-kernel methods. Home range size of geometric tortoises showed large inter-individual variation, and for females, a positive relationship to body size. Females, the larger sex, had larger home ranges and mean daily displacements than males had. Female space use was high through most of the year, except in the wet season, when food was abundant, temperatures relatively low, and soft soils allowed easy nesting. Males used more space and displaced further in the non-nesting than nesting season, perhaps to optimise mating opportunities in the non-nesting season before females ovulate. Home ranges were more elongate and overlapped more in fallow fields than in natural vegetation, suggesting that habitat degradation alters home range structure. The space geometric tortoises used for their annual activities ranged from 1.02 to 44.85 ha. The large home ranges and effects of habitat degradation should influence the size of reserves, and the destiny of geometric tortoises in small habitat fragments.

Temporal patterns of association between the jellyfish Catostylus mosaicus and a sphaeromatid isopod and parasitic anemone

2017 ◽  
Vol 68 (9) ◽  
pp. 1771 ◽  
Author(s):  
Joanna G. Browne ◽  
Kylie A. Pitt ◽  
Mark D. Norman
Keyword(s):  
Time Series ◽  
Life History ◽  
Temporal Variation ◽  
Temporal Patterns ◽  
Temporal Changes ◽  
Maximum Intensity ◽  
Ecological Data ◽  
History Of ◽  
Scyphozoan Jellyfish

Jellyfish form associations with a diverse fauna including parasites and commensals, yet, ecological data on these associations, particularly time series, are rare. The present study examined temporal variation in the intensities and prevalences of two symbionts, namely, a sphaeromatid isopod (Cymodoce gaimardii) and a parasitic anemone (Anemonactis clavus) of the scyphozoan jellyfish Catostylus mosaicus over a 2-year period. Jellyfish were captured from Port Phillip Bay, Victoria, Australia, approximately every 6 weeks and inspected for symbionts. The isopod occurred on C. mosaicus on 16 of the 19 sampling occasions; prevalences ranged from 5 to 85%, and were highest in summer and autumn. Intensity ranged from one to five isopods per jellyfish. Juvenile, immature and mature isopods were present. The parasitic anemone A. clavus occurred only between May and September. Prevalences were lower than for the isopod (on 5–20% of jellyfish when present) as was maximum intensity (two anemones per jellyfish). Catostylus mosaicus appears to play an important role in the life history of a suite of symbionts, and the present study is the first to examine temporal changes in the association of the jellyfish with two of these symbionts.

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