Hummel J.,Institute For Tierwissenschaften |
Findeisen E.,Institute For Tierwissenschaften |
Sudekum E.-H.,Institute For Tierwissenschaften |
Ruf I.,University of Bonn |
And 4 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2011
The circumstances of the evolution of hypsodonty (= high-crowned teeth) are a bone of contention. Hypsodonty is usually linked to diet abrasiveness, either from siliceous phytoliths (monocotyledons) or from grit (dusty environments). However, any empirical quantitative approach testing the relation of ingested silica and hypsodonty is lacking. In this study, faecal silica content was quantified as acid detergent insoluble ash and used as proxy for silica ingested by large African herbivores of different digestive types, feeding strategies and hypsodonty levels. Separate sample sets were used for the dry (n = 15 species) and wet (n = 13 species) season. Average faecal silica contents were 17-46 g kg-1 dry matter (DM) for browsing and 52-163 g kg-1 DM for grazing herbivores. No difference was detected between the wet (97.5±14.4 g kg-1 DM) and dry season (93.5±13.7 g kg-1 DM) faecal silica. In a phylogenetically controlled analysis, a strong positive correlation (dry season r = 0.80, p < 0.0005; wet season r = 0.74 p < 0.005) was found between hypsodonty index and faecal silica levels. While surprisingly our results do not indicate major seasonal changes in silica ingested, the correlation of faecal silica and hypsodonty supports a scenario of a dominant role of abrasive silica in the evolution of high-crowned teeth. © 2011 The Royal Society.
Steuer P.,University of Bonn |
Sudekum K.-H.,University of Bonn |
Tutken T.,University of Bonn |
Tutken T.,University of Mainz |
And 5 more authors.
Functional Ecology | Year: 2014
A key concept of body mass (BM) in niche separation of large herbivores assumes that the decrease in diet quality inherent to increasing BM (due to less selective feeding behaviour) is balanced by a simultaneous increase in digestive ability (due to longer retention times), resulting in no or less-than-expected reduction in digestibility (as measured in the animal as a result of diet quality and digestive ability). However, the second part of this concept has been challenged recently due to theoretical problems and mismatch with empirical data. A proxy for digestibility, such as metabolic faecal nitrogen (MFN), will comprise both information on diet quality and digestive ability in free-ranging animals. In captive animals, if diet is kept constant, such a proxy can exclusively indicate digestive ability. Comparing free-ranging and captive animals under such conditions, one would expect an increase in MFN with BM in captive animals and no relationship between these measures in free-ranging animals if BM was related to digestive ability. We compared captive ungulates on a consistent grass hay diet (17 species; 30-4000 kg BM) to a sample of free-ranging East African ungulates (19 species; 12-4000 kg BM). MFN was used as the major proxy for digestibility. In captive animals, there was no influence of BM on MFN (P = 0·466); for free-ranging animals, a significant decreasing effect of body mass on MFN (P = 0·002) and therefore diet quality was found at a scaling of BM-0·15. In conclusion, scenarios that assume a compensation of the evident decrease in diet quality with BM via an increased digestive ability are not supported by this study. This does not rule out other feeding-related factors in facilitating large BM, such as compensation by an increased diet intake. © 2014 British Ecological Society.
Rubel A.,Zoo Zurich |
Zingg R.,Zoo Zurich
Zoologische Garten | Year: 2015
More space for the elephants, more proximity for visitors. The new Kaeng Krachan Elephant Park marks a further milestone at Zoo Zurich. Thanks to the new management form of "protected contact" the elephants move around more freely, display their natural behaviour, maintain social contacts and even go swimming, and the public will have the chance to get closer to the animals than ever before.The Kaeng Krachan Elephant Park at Zoo Zurich is named after the largest national park in Thailand. The eclosure is dedicated to support projects to help protect Asiatic elephants in Thailand, which includes attempting to resolve the conflicts that oppose farmers and elephants.Zoo Zurich's commitment to the Kaeng Krachan National Park is reflected in its design and a series of educational exhibits. The park includes an observation hut and protective fencing and illustrates how Thai farmers can protect their plantations around the National Park. A hut in ruins and tracks leading along the footpaths display the destructive consequences a visit from the elephants may have. © 2014.
Price E.C.,Durrell Wildlife Conservation Trust |
Wormell D.,Durrell Wildlife Conservation Trust |
Brayshaw M.,Durrell Wildlife Conservation Trust |
Furrer S.,Zoo Zurich |
And 2 more authors.
International Zoo Yearbook | Year: 2012
This paper describes the management techniques developed over 20 years of experience with free-ranging groups of callitrichids at Durrell Wildlife Park (formerly Jersey Zoo), UK, with an additional 12 years of information from Zürich Zoo, Switzerland. Seventeen groups of eight different species have been released in woodland areas at Durrell, and two groups at Zürich. Release periods ranged from 2 weeks to 14 years. The evolution of release protocols is described, along with brief descriptions of problems that have occurred. The advantages and problems of maintaining callitrichids in free-ranging environments are discussed. © 2012 The Authors. International Zoo Yearbook © 2012 The Zoological Society of London.
Burivalova Z.,ETH Zurich |
Burivalova Z.,Universitatstrasse 16 |
Bauert M.R.,Zoo Zurich |
Hassold S.,ETH Zurich |
And 2 more authors.
Biotropica | Year: 2015
A global data set on forest cover change was recently published and made freely available for use (Hansen et al. 2013. Science 342: 850-853). Although this data set has been criticized for inaccuracies in distinguishing vegetation types at the local scale, it remains a valuable source of forest cover information for areas where local data is severely lacking. Masoala National Park, in northeastern Madagascar, is an example of a region for which very little spatially explicit forest cover information is available. Yet, this extremely diverse tropical humid forest is undergoing a dramatic rate of forest degradation and deforestation through illegal selective logging of rosewood and ebony, slash-and-burn agriculture, and damage due to cyclones. All of these processes result in relatively diffuse and small-scale changes in forest cover. In this paper, we examine to what extent Hansen et al.'s global forest change data set captures forest loss within Masoala National Park by comparing its performance to a locally calibrated, object-oriented classification approach. We verify both types of classification with substantial ground truthing. We find that both the global and local classifications perform reasonably well in detecting small-scale slash-and-burn agriculture, but neither performs adequately in detecting selective logging. We conclude that since the use of the global forest change data set requires very little technical and financial investment, and performs almost as well as the more resource-demanding, locally calibrated classification, it may be advantageous to use the global forest change data set even for local conservation purposes. © 2015 The Association for Tropical Biology and Conservation.