44 research outputs found
Pongamia seed cake as a valuable source of plant nutrients for sustainable agriculture
Pongamia, a multipurpose leguminous tree containing non-edible oil, grows widely in India. Oil extracted from the seeds of Pongamia is used as energy source as well as in tanneries while the cake (a byproduct after extracting oil) was found to be rich in all plant nutrients in general and nitrogen (4.28%) and sulfur (0.19%) in particular. Both nitrogen and sulfur were found to be deficient in 100 and 80%, respectively, in soil samples from farmers' fields in Powerguda village of Adilabad district, Andhra Pradesh, India. Use of Pongamia seed cake as a source of plant nutrients for maize, soyabean and cotton was found beneficial in participatory research and development trials on farmers' fields. Further, application of critically deficient micronutrients such as zinc and boron and secondary nutrient sulfur increased crop yields by 16.7 and 19% in soyabean and cotton, respectively. In addition, B:C ratios of 5.03, 1.81 and 2.04 were obtained for soyabean, maize and cotton, respectively, with use of cake as a source of N, however it needed higher initial investment
Long-term Site Fidelity and Individual Home Range Shifts in Lophocebus albigena
We investigated long-term site fidelity of gray-cheeked mangabey (Lophocebus albigena) groups in Kibale National Park, Uganda. Concurrently, we monitored shifts in home range by individual females and subadult and adult males. We documented home range stability by calculating the area of overlap in successive years, and by recording the drift of each group’s monthly centroid from its initial location. Home ranges remained stable for 3 of our 4 groups (overlap over 10 yr >60%). Core areas were more labile, but group centroids drifted an average of only 530 m over the entire decade. Deviations from site fidelity were associated with dispersal or group fission. During natal dispersal, subadult males expanded their home ranges over many months, settling ≤4 home ranges away. Adult males, in contrast, typically dispersed within a few days to an adjacent group in an area of home range overlap. Adult males made solitary forays, but nearly always into areas used by their current group or by a group to which they had previously belonged. After secondary dispersal, they expanded their ranging in the company of their new group, apparently without prior solitary exploration of the new area. Some females also participated in home range shifts. Females shifted home ranges only within social groups, in association with temporary or permanent group splits. Our observations raise the possibility that male mangabeys use a finder-joiner mechanism when moving into new home ranges during secondary dispersal. Similarly, females might learn new resource locations from male immigrants before or during group fission
Abrasive, Silica Phytoliths and the Evolution of Thick Molar Enamel in Primates, with Implications for the Diet of Paranthropus boisei
Background: Primates—including fossil species of apes and hominins—show variation in their degree of molar enamel thickness, a trait long thought to reflect a diet of hard or tough foods. The early hominins demonstrated molar enamel thickness of moderate to extreme degrees, which suggested to most researchers that they ate hard foods obtained on or near the ground, such as nuts, seeds, tubers, and roots. We propose an alternative hypothesis—that the amount of phytoliths in foods correlates with the evolution of thick molar enamel in primates, although this effect is constrained by a species ’ degree of folivory. Methodology/Principal Findings: From a combination of dietary data and evidence for the levels of phytoliths in plant families in the literature, we calculated the percentage of plant foods rich in phytoliths in the diets of twelve extant primates with wide variation in their molar enamel thickness. Additional dietary data from the literature provided the percentage of each primate’s diet made up of plants and of leaves. A statistical analysis of these variables showed that the amount of abrasive silica phytoliths in the diets of our sample primates correlated positively with the thickness of their molar enamel, constrained by the amount of leaves in their diet (R 2 = 0.875; p,.0006). Conclusions/Significance: The need to resist abrasion from phytoliths appears to be a key selective force behind the evolution of thick molar enamel in primates. The extreme molar enamel thickness of the teeth of the East African homini
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The bii4africa dataset of faunal and floral population intactness estimates across Africa’s major land uses
Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of an ‘intact’ reference population of a species group in a particular land use, on a scale from 0 (no remaining individuals) to 1 (same abundance as the reference) and, in rare cases, to 2 (populations that thrive in human-modified landscapes). The resulting bii4africa dataset contains intactness scores representing terrestrial vertebrates (tetrapods: ±5,400 amphibians, reptiles, birds, mammals) and vascular plants (±45,000 forbs, graminoids, trees, shrubs) in sub-Saharan Africa across the region’s major land uses (urban, cropland, rangeland, plantation, protected, etc.) and intensities (e.g., large-scale vs smallholder cropland). This dataset was co-produced as part of the Biodiversity Intactness Index for Africa Project. Additional uses include assessing ecosystem condition; rectifying geographic/ taxonomic biases in global biodiversity indicators and maps; and informing the Red List of Ecosystems
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Averting biodiversity collapse in tropical forest protected areas
The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon¹⁻³. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses⁴⁻⁹. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc
Population status of black and white colobus monkeys (Colobus guereza) in Kakamega Forest, Kenya: are they really on the decline?
Eastern black and white colobus monkeys, or guerezas (Colobus guereza), are among the few primate species that have traditionally been regarded as not being adversely affected by habitat degradation. This view was recently challenged by von Hippel et al. (2000) who, using data from short-term censuses in 1992 and 1998, reported a striking decline in guereza density over a six-year period of light to moderate habitat degradation at Isecheno study site in the Kakamega Forest, Kenya. In this paper, I present evidence from my own more intensive study during the same period that suggests that the guereza population at Isecheno is actually quite robust and may in fact be increasing. I provide evidence to suggest that the census methods adopted by von Hippel and his colleagues are prone to overestimating density and that the decline in guereza density that they reported probably did not occur. My study suggests that brief censuses based on group counts over a given area, even when conducted by multiple observers, are not sufficient for accurately determining primate distributions and densities in rainforest environments. Data on animal distribution and density play a critical role in the development of conservation strategies and it is therefore important that these data be relatively accurate if biologists are to make informed conservation decisions.Key words: population density, census, block method, group count method, birth rate, interbirth interval, forest degradation, conservation
Evaluating the suitability of planted forests for African forest monkeys: A case study from Kakamega
As natural forest cover declines, planted forests have come to occupy an increasing percentage of the earth's surface, yet we know little about their suitability as alternative habitat for wildlife. Although some primate species use planted forests, few studies have compared primate populations in natural and nearby planted forests. From March 2006 to July 2010, we conducted line transect surveys and assessed group sizes and compositions in natural and nearby 60-70 year old mixed indigenous planted forest to determine the densities of diurnal primate species (Colobus guereza, Cercopithecus mitis, C. ascanius) in these two forest types at Isecheno, Kakamega Forest, Kenya. Line transect data were analyzed using the Encounter Rate, Whitesides, and Distance sampling methods, which all provided broadly consistent results. We found that all three diurnal primate species occupy both natural and planted forest at Isecheno. However, group densities of the two Cercopithecus species were 42-46% lower in planted than in natural forest. Colobus guereza achieved comparable group densities in the two forest types, although the species is found in smaller groups, and thus at lower (35%) individual density, in planted than in natural forest. Following a logging episode in the planted forest mid-way through our study, Cercopithecus ascanius group densities fell by 60% while C. mitis and Colobus guereza group densities remained stable over the next two years. Overall, our results suggest that while primate species vary in their response to habitat disturbance, planted forest has the potential to contribute to the conservation of some African monkey species. Even for the relatively flexible taxa in our study, however, 60-70 year old mixed indigenous planted forest failed to support densities comparable to those in nearby natural forest. From the perspective of Kakamega's primates, planted forests may supplement natural forest, but are not an adequate replacement for it. Am. J. Primatol. 74:77-90, 2012