EC74-2033 Structural Lighting in the Home

Extension Circular 74-2033 talks about installing lighting in homes

Group differences in feeding and diet composition of wild western gorillas

The ecological-constraints model posits that living in larger groups is associated to higher travel costs and reduced nutritional intake due to within-group feeding competition setting upper group size limits. While this is critical for frugivorous mammals, the model is less ubiquitous for folivores who feed on more abundant and evenly distributed food. The seasonally frugivorous diet of western gorillas (Gorilla gorilla) provides the opportunity to study the ecological-constraints model in the largest primate species. We investigated how two groups of western gorillas of difering sizes (N= 9, N= 15) in Central African Republic, responded to seasonal variation in fruit availability in terms of activity and diet. We used continuous focal animal sampling during periods of high (July–August 2011) and low (October 2011–January 2012) fruit availability, measured by monthly phenological scores. While diet diversity, resting and moving time did not difer between groups, overall the smaller group spent more time feeding than the larger group although this became less evident when fruit was more available. The smaller group was more frugivorous than the larger group. However, the larger group increased more steeply fruit consumption when fruit was more available, and incorporated more insects, young leaves and bark when fruit was less available, when compared to the smaller group. Up to a certain limit, the fexibility of large, seasonal frugivores to survive on a more folivorous diet may bufer the upper limit group size, suggesting deviation from the ecological-constraints model as in some folivores

Foraging efficiency in temporally predictable environments: is a long-term temporal memory really advantageous?

Cognitive abilities enabling animals that feed on ephemeral but yearly renewable resources to infer when resources are available may have been favoured by natural selection, but the magnitude of the benefits brought by these abilities remains poorly known. Using computer simulations, we compared the efficiencies of three main types of foragers with different abilities to process temporal information, in spatially and/or temporally homogeneous or heterogeneous environments. One was endowed with a sampling memory, which stores recent experience about the availability of the different food types. The other two were endowed with a chronological or associative memory, which stores long-term temporal information about absolute times of these availabilities or delays between them, respectively. To determine the range of possible efficiencies, we also simulated a forager without temporal cognition but which simply targeted the closest and possibly empty food sources, and a perfectly prescient forager, able to know at any time which food source was effectively providing food. The sampling, associative and chronological foragers were far more efficient than the forager without temporal cognition in temporally predictable environments, and interestingly, their efficiencies increased with the level of temporal heterogeneity. The use of a long-term temporal memory results in a foraging efficiency up to 1.16 times better (chronological memory) or 1.14 times worse (associative memory) than the use of a simple sampling memory. Our results thus show that, for everyday foraging, a long-term temporal memory did not provide a clear benefit over a simple short-term memory that keeps track of the current resource availability. Long-term temporal memories may therefore have emerged in contexts where short-term temporal cognition is useless, i.e. when the anticipation of future environmental changes is strongly needed

The complex Y-chromosomal history of gorillas

Studies of the evolutionary relationships among gorilla populations using autosomal and mitochondrial sequences suggest that male-mediated gene flow may have been important in the past, but data on the Y-chromosomal relationships among the gorilla subspecies are limited. Here, we genotyped blood and noninvasively collected fecal samples from 12 captives and 257 wild male gorillas of known origin representing all four subspecies (Gorilla gorilla gorilla, G. g. diehli, G. beringei beringei, and G. b. graueri) at 10 Y-linked microsatellite loci resulting in 102 unique Y-haplotypes for 224 individuals. We found that western lowland gorilla (G. g. gorilla) haplotypes were consistently more diverse than any other subspecies for all measures of diversity and comprised several genetically distinct groups. However, these did not correspond to geographical proximity and some closely related haplotypes were found several hundred kilometers apart. Similarly, our broad sampling of eastern gorillas revealed that mountain (G. b. beringei) and Grauer's (G. b. graueri) gorilla Y-chromosomal haplotypes did not form distinct clusters. These observations suggest structure in the ancestral population with subsequent mixing of differentiated haplotypes by male dispersal for western lowland gorillas, and postisolation migration or incomplete lineage sorting due to short divergence times for eastern gorillas

Western Lowland Gorillas (Gorilla gorilla gorilla) Change Their Activity Patterns in Response to Frugivory

International audienceThe most important environmental factor explaining interspecies variation in ecology and sociality of the great apes is likely to be variation in resource availability. Relatively little is known about the activity patterns of western lowland gorillas (Gorilla gorilla gorilla), which inhabit a dramatically different environment from the well-studied mountain gorillas (G. beringei beringei). This study aims to provide a detailed quantification of western lowland gorillas' activity budgets using direct observations on one habituated group in Bai Hokou, Central African Republic. We examined how activity patterns of both sexes are shaped by seasonal frugivory. Activity was recorded with 5-min instantaneous sampling between December 2004 and December 2005. During the high-frugivory period the gorillas spent less time feeding and more time traveling than during the low-frugivory period. The silverback spent less time feeding but more time resting than both females and immatures, which likely results from a combination of social and physiological factors. When compared with mountain gorillas, western lowland gorillas spend more time feeding (67 vs. 55%) and traveling (12 vs. 6.5%), but less time resting (21 vs. 34%) and engaging in social/other activities (0.5 vs. 3.6%). This disparity in activity budgets of western lowland gorillas and mountain gorillas may be explained by the more frugivorous diet and the greater dispersion of food resources experienced by western lowland gorillas. Like other apes, western lowland gorillas change their activity patterns in response to changes in the diet

Ranging patterns of a large western Gorilla group at Dipikar Island in the Campo—Ma’an National Park, Cameroon

The study site, Dipikar Island (2° 10’-2°18’N, 2° 17’-2°14’E), is located in the Campo Ma’an National Park (CMNP), in South Region, Cameroon. In late 2010, after assessing the feasibility for gorilla habituation, the World Wide Fund for Nature’s (WWF) Kudu—Zombo Program, in collaboration with the Ministry of Forestry and Wildlife of Cameroon (MINFOF), selected this site in order to develop a controlled ecotourism program for gorilla viewing. We began the preliminary phase of fieldwork in May 2011 with the priority of establishing an extensive trail system, developing and refining the habituation protocol and identifying gorilla groups within the study area. From March 2012, the trail of the focal group Akiba was followed with varying success from nest to nest. We rarely noted signs of other gorilla groups during our consecutive monitoring of the Akiba group. The group size was extrapolated based on nest counts and the average nest size was 32.4. We superimposed a 500 m x 500 m grid system on the map to allow comparative measurements of home range size. Home range, monthly range and the frequency of quadrant use by the Akiba group were calculated as the sum of all 500 m x 500 m quadrants entered. The “core area” was defined as the sum of quadrants that, in descending order of entry, cumulatively accounted for 75% of the group’s total quadrant entries. Daily path length (DPLs) was calculated from the maps by measuring the distance traveled between each consecutive nest site. From March 2012 through December 2014, the Akiba group was followed during 596 days, representing 74% of the effort days, when the teams were in the field (n=807 days). Group Akiba entered a total of 256 quadrants, resulting in a contiguous home range of 64 Km2 over three years and an average annual home range of 40.4 km2 with an annual home range of 39.8 km2 in 2012 (Y1), 45.5 km2 in 2013 (Y2) and 36 km2 in 2014 (Y3). For the total number of quadrants entered by Akiba, 62% was visited in Y1, 71% in Y2 and 56% in Y3. However, the size of the area used on a monthly basis was smaller averaging 11 Km2 (N = 29, range = 5.8 - 20.5, SD = 3.4). Of their total home range, the Akiba group intensely used an even smaller area, resulting in a core area of 3.5 Km2: 75% of the group’s visits were concentrated in 5.5% of the total home range visited throughout the study period. On a monthly basis, Akiba group moved in limited areas, with frequent visits outside in neighboring quadrants. For the total number of quadrants visited by the group during the period of study, it appears that the group concentrated its movements around the core area. In fact, 30% of the quadrants, including the core area, were visited in the three years, while 8% in Y1 and Y2, 5% in Y2 and Y3, 16% in Y1 and Y2. Only 18. 4% of quadrants were visited exclusively in Y2, 15% in Y3 and 7.4 in Y1. Throughout the study period, the mean daily path length (DPL) was 1600 m (N = 502, range = 180-5300 m, SD = 858). Interestingly, the group’s home range seemed to gradually decrease after the first year of follows and a mean monthly DPL of 1845 m (N=12, range =1408–2273 m, SD = ± 275 m) was recorded between March 2012 to February 2013 (P1) and a mean monthly DPL of 1268.3 m (N= 17, range = 958.4-1637 m, SD = ± 225 m) was recorded between March 2013 to December 2014 (P2), excluding August 2014).   The difference between the mean monthly DPL during P1 and the mean monthly DPL during P2 is significant (P <0.05). The result seems to indicate that DPL decrease after the 1st year of following, suggesting that the group Akiba became more habituated or tolerant to the teams following their traces. The group seems to have a very large home range but not really long DPL. Even with the large home range, they still range mostly around their core area.Je remercie le WWF — CCPO (Cameroon Country Programme Office) qui a initié le projet d’habituation des gorilles au Parc National de Campo Ma’an (PNCM) et son partenaire le ministère des forêts et de la faune du Cameroun qui a autorisé cette initiative sur le terrain. Plus spécifiquement, je remercie le programme Kudu-Zombo du WWF-CCPO et le service de la conservation du PNCM pour le soutien et la facilitation qu’ils m’ont apportés sur le terrain. Mes remerciements vont également à l’endroit du Programme de Compétitivité des Filières de Croissance (PCFC) de la Banque Mondiale, du WWF International (Fondation Segré), du WWF — Allemagne en particulier Dr Ilka Herbinger pour le support financier. Je remercie les pisteurs du projet d’habituation des gorilles du PNCM particulièrement, Assembe Dieudonné, Mana Jean, Olé Pierre, Mba Joseph, Bilendé Jean Sondo, Ndoungou Paul, Doungué Lucien, Tsimi Kossi Francis et Edjo Martin pour leurs efforts remarquables dans le suivi des gorilles et la collecte des données. Un merci très particulier à Nomo Maurice Nomo pour le soutien moral et les encouragements au quotidien

Mammal extinctions and the increasing isolation of humans on the tree of life

International audienceA sixth great mass extinction is ongoing due to the direct and indirect effects of human pressures. However, not all lineages are affected equally. From an anthropocentric perspective, it is often purported that humans hold a unique place on Earth. Here, we show that our current impacts on the natural world risk realizing that expectation. We simulated species loss on the mammalian phylogenetic tree, informed by species current extinction risks. We explored how Homo sapiens could become isolated in the tree if species currently threatened with extinction disappeared. We analyzed correlates of mammal extinctions risks that may drive this isolation pattern. We show that, within mammals, and more particularly within primates, extinction risks increase with the number of known threat types, and decrease with geographic range size. Extinctions increase with species body mass, trophic level, and the median longitudinal extent of each species range in mammals but not within primates. The risks of extinction are frequently high among H. sapiens close relatives. Pruning threatened primates, including apes (Hominidae, Hylobatidae), from the tree of life will lead to our species being among those with the fewest close relatives. If no action is taken, we will thus not only lose crucial biodiversity for the preservation of Earth ecosystems, but also a key living reference to what makes us human

Influence of food availability on the diet and activity budget of two western lowland gorilla (Gorilla gorilla gorilla) groups of differing size in the Dzanga-Ndoki National Park, Central African Republic

Variation in food availability, body size and group size are known to influence primate diet and activity budgets. Here we report how seasonal food availability shapes the diet and activity patterns of two habituated western lowland gorilla (WLG) groups of differing size. WLGs are ripe fruit opportunists, showing dietary flexibility when preferred foods are scarce. However, as fruit can be rare/ patchily distributed, as intra-group feeding competition increases with group size, access to individual patches may be limited. We thus predicted that frugivory decreases with increased group size and influences diet and activity budgets accordingly (increased diet breadth and time feeding since relying on alternative/lower quality food). First, we compared food availability between home-ranges by monitoring leafing/fruiting patterns of major gorilla food trees. Second, we compared the groups’ activity budgets and diet composition/diversity, testing for differences between high (HF) and low fruit seasons (LF). We measured gorilla activity over six months by continuous focal sampling of 16 target animals rotated daily from both groups (N=9 and N=15). Our results confirm that WLG diet consisted mainly of fruits (36%, then: stems 24%; leaves 21%; insects 14%; other food types 3%, and bark 2%) and spend most of their time feeding (39%, then: resting 33%; traveling 19%; social 5%, and other activities 4%). However, contrary to our predictions, we found no group differences within or between seasons: irrespective of group size both spent significantly less time feeding, but more time traveling and socializing, and consumed significantly more fruits, less leaves and bark during the HF compared to the LF. Our results show that WLG activity budgets and diet appear to vary more in response to ripe fruit availability than group size. We suggest that WLGs may cope with increased group size costs through other mechanisms such as group spread, rather than lowering diet quality or further changing activity patterns. Such flexibility may better allow WLG groups to track ripe fruits when available but, unlike sympatric chimpanzees, switch to more herbivorous diets when necessary, adjusting activity budgets accordingly ; WLGs thus may be considered more resilient faced with environmental change such as forest degradation

Observational monitoring of clinical signs during the last stage of habituation in a wild Western Gorilla Group at Bai Hokou, Central African Republic

Anthropozoonotic disease transmission to great apes is a critical conservation concern, and has raised ethical doubts regarding ape habituation. We monitored over a 3-year period clinical signs within a group of wild western gorillas (G. gorilla) undergoing habituation at Bai Hokou, Central African Republic. The majority of observations consisted of singular coughs and sneezes among the gorillas. These were the only clinical signs that significantly and positively increased over the years. No changes in the demography of the study group were observed. While clinical signs are not necessarily indicative of 'disease' or other health-related problems, we discuss how long-term records of clinical signs provide useful information when health monitoring, and the importance of the rigid application of preventive disease transmission protocols. Copyright © 2013 S. Karger AG, Basel

Wild chimpanzees on the edge : nocturnal activities in cropland

ACL (avec facteur d'impact)International audienceIn a rapidly changing landscape highly impacted by anthropogenic activities, the great apes are facing new challenges to coexist with humans. For chimpanzee communities inhabiting encroached territories, not bordered by rival conspecifics but by human agricultural fields, such boundaries are risky areas. To investigate the hypothesis that they use specific strategies for incursions out of the forest into maize fields to prevent the risk of detection by humans guarding their field, we carried out video recordings of chimpanzees at the edge of the forest bordered by a maize plantation in Kibale National Park, Uganda. Contrary to our expectations, large parties are engaged in crop-raids, including vulnerable individuals such as females with clinging infants. More surprisingly chimpanzees were crop-raiding during the night. They also stayed longer in the maize field and presented few signs of vigilance and anxiety during these nocturnal crop-raids. While nocturnal activities of chimpanzees have been reported during full moon periods, this is the first record of frequent and repeated nocturnal activities after twilight, in darkness. Habitat destruction may have promoted behavioural adjustments such as nocturnal exploitation of open croplands