Catálogo de publicaciones - libros

Representatives of eight genera of Ethiopian rodents were collected and their chromosome characteristics were analyzed for the first time in the northern montane part of the country (between Tana Lake and Mt Guna, altitudes from 1800 to 3800 m a.s.l. at latitudes between 11–12° N). Even preliminary chromosome analysis gives rich empirical materials for the correction of current systematic definitions, interpretation of endemic taxa and evaluation of possible relationships with the already known karyotypic forms in Ethiopia and abroad. As a result of this study, four new karyotypes are manifested and five karyotypic descriptions already known for Ethiopian species are confirmed.

Coat colour variation of , the largest and most striking species of scaly-tailed squirrels in Africa, was studied based on the examination of 142 skins. Within a relatively small distribution area from central Liberia to Ghana, three distinct colour morphs (dorsal surface and tail black; dorsal surface black with narrow white margins and white tail; dorsal surface partly black with broad white margins and white tail) were found. The observed variation is not clinal but changes stepwise across the Sassandra and Bandama Rivers which divide the distribution clearly into a western, central, and eastern range. This pattern is weakly paralleled by variation of skull size. Between the three sub-populations there is probably reduced gene flow and they represent relicts of a formerly wider distribution. We assign two available names to the western and eastern and suggest a new name for the central population.

Within the family Bathyergidae (subterranean African mole-rats), and are the most speciose genera. Whereas each species can be characterized karyologically and from mitochondrial gene sequence data genetically, most of them exhibit marked intraspecific polymorphism and an overlap in morphological and biometric traits making them very hard to discern for taxonomic studies. As a consequence, pelage colour, body size and craniometric characters are inappropriate for species diagnosis.

Here we report on a comparative morphological and biometric analysis of the auditory ossicles in seven species of and one species of . While species can be identified by a unique combination of oto-morphological features, there is also a strong correlation between biometry of functionally relevant traits and the habitat. Middle ear biomechanical efficiency and hence hearing sensitivity appears to improve with increasing humidity of the habitat. This trend is evident even when comparing different populations at an intraspecific level.

The Murid rodent diversity has been sampled following the 9 Meridian in the east of Guinea from the forest region to Sudanian savannas of southern Mali. This represents the first small mammals survey in North Guinea. Murid diversity patterns have been researched using correspondence analysis and faunal comparisons. A difference between southern forest communities and northern ones is observed. is found only in houses in southern Guinea while in the north it is found in all sampled habitats. is absent from the forest zone, but found from the ecotone forest-savanna to the north, and it seems that this species never enter houses. Implications for Lassa fever transmission are discussed.

Human impact causes land degradation with negative effects on both density and genetic variability of animal populations. Recent studies indicate that host genetic diversity plays an important role in buffering populations against widespread epidemics. Within the mammalian immune system the highly variable major histocompatibility complex (MHC) plays a central role in pathogen defence. In this study we used two common African rodent species, the hairy-footed gerbil () and the striped mouse (), as model organisms to investigate effects of different land use on (1) vegetation structure and population density, (2) parasite burden and (3) the importance of the MHC-constitution for resistance to parasites by comparing two sites on a private nature reserve and one site on a commercially used farm in the Southern Kalahari/South Africa. Both rodents were significantly more abundant and showed more helminths infections in the two less degraded nature reserve sites, although the MHC diversity was not significantly different between sites. Either higher parasite species richness or the increased host population density in the more diverse nature reserve sites might be responsible for the higher parasite prevalence. In both species significant associations were found between specific alleles and infection status, giving evidence for the significance of the MHC in the defence of pathogens.

We analyzed two mitochondrial gene fragments to assess genetic divergence within the genus endemic to Ethiopia and its phylogenetic relationships with related genera. The phylogenetic analysis supported the monophyly of the Arvicanthini-Otomyini group and revealed that is clearly a member of Arvicanthini. Our study demonstrated that and belong to remarkably different mitochondrial lineages, the estimated divergence time between them is 4.10–5.38 Myr. Such early splitting of specialized forest dweller, , from its sole congener supposes a more ancient formation of some elements of Ethiopian forest rodent fauna than is assumed today.

The taxonomy of the genus has been hotly debated. Following recent clarifications on the phylogeny of and species boundaries within the genets, we propose a new classification, including discriminant morphological diagnoses, which provides for the first time a synthetic description of the reassessed species diversity within the genus (17 species). Prospects concerning further investigations on the systematics of the genets are discussed.

In practise the overall efficiency of data-basing the inventory of traditional entomological collections depends on two factors: suitable software and management measures to ensure the highest possible data quality already in the input process. Lessons learned from the development of the specimenbased database BIODAT and preliminary results of the DIG-(Digitization of key Insect groups at ZFMK) project, which is especially designed to develop a ‘good practise’, recommend: (1) a lockstep programme for data-basing, (2) data entry of collection units and split record function, (3) visualisation of geo-referenced locations/sites during data entry, (4) semi-automatic/automatic data transformation from original format into additional alternative ones, (5) semiautomatic data transfer of taxa- and geo-referenced information units. Current activities deal with the introduction of semantic feedback mechanisms into the practise of data-basing entomological collections.

The Niger Inland Delta is one of the most fragile ecosystems in the Sahelian zone of Africa. Annual flooding of vast plains during September to December depends on water levels of the main rivers Niger and Bani. The interaction among pre-flood, flood and post-flood conditions strongly affects land cover patterns in and around the delta. Assessing and mapping land cover dynamics is rendered possible by systematic application of remote sensing and image analysis. Thus support a better understanding of state and changes in the vulnerable ecosystem. Operational missions of earth observation contribute to the establishment of multi-seasonal and multi-annual monitoring schemes. This paper aims to show the potential of spectral high-resolution imaging spectrometry (MERIS) for monitoring spatio-temporal patterns of land use and land cover change in the Niger Inland Delta. 5 MERIS scenes, covering one vegetation-cycle from August 2002 until June 2003, have been used therefore.

Interactions of biotic and abiotic factors are critical in determining population dynamics and maintenance of high diversity in tropical rainforests. An investigation was conducted to test the hypothesis that tree species composition and dispersion influence spatial pattern of soil properties on a small scale of meters. Soil variables (pH, EC and total and water extractable (available) K, Ca, Mg and Mn) were highly heterogeneous in both vertical and horizontal dimensions. Available Mn was the most variable (coefficient of variation CV = 76%) parameter and pH the least (CV = 4%). There was an inverse relationship between abundant levels of available cations and heterogeneity. Plots with high heterogeneity in available cations had low tree diversity but there was no evident pattern between total concentration of cations and tree diversity. Tree diversity was negatively correlated to variability of available Mn (r = −0.7). These findings indicate that tree diversity influences soil heterogeneity hence contributing to maintenance of high diversity in tropical rainforests. The results show that the observed soil patterns are caused by geogenic processes as well as processes influenced by vegetation. The raising effect of the vegetation on the elements is expected in the order from Mn, Ca, Mg to K. This vegetation effect indicates the significance of maintaining a closed canopy in tropical rain forests. Geodiversity is thus correlated to biodiversity and needs to be more recognized in ecological research.