关键词： Crocuta crocuta   Leptailurus serval   lion   Odzala-Kokoua   Panthera leo   Republic of Congo   serval   spotted hyena  

摘要： The catchment of the Congo River basin contains an extensive forest-savanna mosaic, which once harbored significant populations of lions (Panthera leo), African wild dogs (Lycaon pictus), and spotted hyenas (Crocuta crocuta). The mosaic's northern part, stretching across the Republic of Congo and southern Gabon, is today geographically isolated. Uncontrolled hunting has led to a gradual decrease in its ungulate populations, and today African wild dogs are considered extinct within the Congo Basin. Lions and spotted hyenas suffered an extreme collapse of their respective former ranges, and in the Republic of Congo both species are believed to survive exclusively in the Odzala-Kokoua National Park (OKNP). We surveyed all extensive savanna areas within this park, to determine the current status of savanna carnivores. We conducted 460 km of track searches on foot, and operated 25 remote camera traps across the survey area over 424 trap-days. We detected no sign of lion presence in the park. Spotted hyena tracks were widespread, and our camera traps recorded 154 hyena photographs, representing 46 different individuals. We also recorded leopard (Panthera pardus), serval (Leptailurus serval), and African golden cat (Caracal aurata) within the survey area. Although lions are likely extinct in the Republic of Congo and neighboring Gabon, our results highlight the importance of OKNP for the regional conservation of spotted hyenas and smaller savanna carnivores.

关键词： MAMMALS -- Research   SAVANNA animals   RESEARCH   MAMMAL ecology   BIRDS of prey   SAVANNA ecology  

摘要： Little is known about the dynamics of small mammals in tropical savanna: a critical gap in our understanding of Africa's best known ecosystems. Historical evidence suggested small mammals peak in abundance (outbreak) in Serengeti National Park (SNP), as in agricultural systems. We asked 1) what are bottom-up drivers of small mammals and 2) do predators have top-down effects? We documented dynamics of small mammals, birds of prey, and mammalian carnivores in SNP and agricultural areas. We used climatic fluctuations and differences between unmodified and agricultural systems as perturbations to examine trophic processes, key to understanding responses to climate change and increasing human pressures. Data were derived from intermittent measures of abundance collected 1968-1999, combined with systematic sampling 2000-2010 to construct a 42-year time series. Data on abundance of black-shouldered kites (1968-2010), eight other species of rodent-eating birds (1997-2010), and 10 carnivore species (1993-2010) were also collated. Outbreaks occurred every 3-5 years in SNP, with low or zero abundance between peaks. There was a positive relationship between rainfall in the wet season and 1) small mammal abundance and 2) the probability of an outbreak, both of which increased with negative Southern Oscillation Index values. Rodent-eating birds and carnivores peaked 6-12 months after small mammals. In agricultural areas, abundance remained higher than in natural habitats. Abundances of birds of prey and mammalian carnivores were extremely low in these areas and not related to small mammal abundance. Small mammals are an important food resource for higher trophic levels in the Serengeti ecosystem. Changes in climate and land use may alter their future dynamics, with cascading consequences for higher trophic levels, including threatened carnivores. Although outbreaks cause substantial damage to crops in agricultural areas, small mammals also play a vital role in maintaining some of

关键词： Metazoa   phylogeny   body plan   scenario  

摘要： A renewed emphasis on the gaps in organization that exist between the crown-group body plans of higher-level animal taxa is a hallmark of the emerging consensus in metazoan phylogenetics. Bridging these gaps is the greatest hurdle that stands in the way of translating our knowledge of phylogeny into a renewed understanding of the macroevolution of animal body plans. Unless a good fossil record is available, there is little hope that we will be able to bridge many of these gaps empirically. We have, therefore, little choice but to resort to our more-or-less informed imagination to produce the historical narratives that are the ultimate goal of our studies of animal evolution. Only by fully engaging with the challenges of devising testable scenarios will we be able to tell where along the spectrum of science and fiction our understanding of animal body plan evolution will finally come to rest.

关键词： carbon   Cerrado   Desmodus rotundus   food chain   nitrogen  

摘要： Carbon and nitrogen stable isotopes were used to track major dietary variations in arthropods found in a cave located in a neotropical savanna in Central Brazil. We determined the delta C-13 and delta N-15 for cave crickets, cockroaches, spiders, guano of a hematophagous bat, and leaf litter found on the ground near the cave entrance. The delta C-13 and delta N-15 for the cricket and cockroaches showed that bat guano was not the only food item for these arthropods. They had intermediate delta C-13 and delta N-15 between bat guano and leaf litter, which means that they consumed additional food resources other than guano in their diet, independent of distribution of guano deposits in the cave. The spiders, predators with great mobility, seemed to not have a preferential diet item since their isotope signals indicated they hunt both crickets and cockroaches. The delta C-13 of the bat guano (-15.4 parts per thousand) indicated that the diet of these hematophagous bats relied on animals fed with C-4 plants. The conversion of native savanna vegetation of which the debris is mostly from C-3 plants, to pasture, based on C-4 African grass, a remarkably common land use transformation in the region, is indirectly influencing the diet of hematophagous bats, which basically relied on exotic fauna. The C and N stable isotope ratios showed that the arthropods inside the cave do not rely solely on bat guano for their diet, but interact directly with the external environment, through litter debris, indicating a significant exchange of energy and matter between the cave environment and the surrounding area.

关键词： Antechinus   Agilis   Swainsonii   Fuscipes   Habitat loss   Relative abundance   Performance indices   Conditional inference tree   Random forests  

摘要： Anthropogenic habitat loss, fragmentation and degradation often co-occur in a landscape and their relative influence on a native animals' health and survival can be difficult to determine. We examined the influence of these environmental variables on the estimated relative abundance of some small mammal species in a large area (similar to 2500 km(2)) of southeastern Australia. Using the agile antechinus (Antechinus agilis) as a model, we also examined the association between these variables and three population performance indices, mass-size residuals (MSR;indexing fat reserves), the neutrophil/lymphocyte ratio (N:L;indexing physiological stress) and red blood cell counts (RBC;indexing regenerative anaemia). Study sites were in either highly disturbed and fragmented, or relatively undisturbed, continuous Eucalyptus forest. We generated conditional inference tree statistical models to identify the relative importance of up to 49 ecological variables in explaining variation in small mammal abundance and performance indices. Habitat loss was important in explaining small mammal abundance, as were the abundances of the same species in neighbouring study sites. The models also suggested that the habitat area required to support a 'healthy' population was greater in the larger species examined. Autocovariates of neighbouring site same-species abundances and habitat fragmentation were the next most important influences on small mammal relative abundance, implying that metapopulations may be important for population persistence, especially in bush rats (Rattus fuscipes). Habitat degradation, reflected in structural and floristic features, was less important, but explained some variance in relative abundances. For agile antechinus populations, time of year, degree of forest fragmentation and extent of native tree cover were important in explaining performance indices. Results indicated that habitat reduction per se was a significant threatening process for small mammals. Hab

关键词： Aspen   Birch   Climate change   Plant-insect interactions   Malacosoma disstria   Temperature  

摘要： As the world's climate warms, the phenologies of interacting organisms in seasonally cold environments may advance at differing rates, leading to alterations in phenological synchrony that can have important ecological consequences. For temperate and boreal species, the timing of early spring development plays a key role in plant-herbivore interactions and can influence insect performance, outbreak dynamics, and plant damage. We used a field-based, meso-scale free-air forest warming experiment (B4WarmED) to examine the effects of elevated temperature on the phenology and performance of forest tent caterpillar (Malacosoma disstria) in relation to the phenology of two host trees, aspen (Populus tremuloides) and birch (Betula papyrifera). Results of our 2-year study demonstrated that spring phenology advanced for both insects and trees, with experimentally manipulated increases in temperature of 1.7 and 3.4 A degrees C. However, tree phenology advanced more than insect phenology, resulting in altered phenological synchrony. Specifically, we observed a decrease in the time interval between herbivore egg hatch and budbreak of aspen in both years and birch in one year. Moreover, warming decreased larval development time from egg hatch to pupation, but did not affect pupal mass. Larvae developed more quickly on aspen than birch, but pupal mass was not affected by host species. Our study reveals that warming-induced phenological shifts can alter the timing of ecological interactions across trophic levels. These findings illustrate one mechanism by which climate warming could mediate insect herbivore outbreaks, and also highlights the importance of climate change effects on trophic interactions.

关键词： nutrient release rate   phosphorus   termites   nutrient cycling   dung beetles   dung deposition   carbon   nitrogen   faeces   African herbivores  

摘要： Although dung of mammalian herbivores is an important pathway for nutrient return in savanna ecosystems, differences in dung decomposition rates among species have been little studied. We measured the rates of dung deposition and decomposition for various herbivores in a moist Tanzanian savanna and the related differences among species to nutrient concentrations and the activities of soil macrofauna (e.g. different mesh sizes of decomposition bags, or presence and absence of dung beetles). Dung C:N:P stoichiometry varied widely among species, which could in part be explained by differences in feeding strategy (browsers vs. grazers) and digestive physiology (ruminants vs. non-ruminants). Rates of both decomposition and nutrient release were influenced by the C:N:P stoichiometry of dung, with lower relative losses of the least abundant nutrient in the dung. Surprisingly, soil macrofauna increased the relative losses of the least abundant nutrient, thereby stabilizing the ratio of N loss to P loss. Dung beetles increased rates of N and P release from wildebeest dung significantly and also increased N availability in the soil. We conclude that rates of nutrient return in dung depend not only on where herbivores deposit their dung, but also on its C:N:P stoichiometry, the activity of soil macrofauna and interactions between these factors. These factors may therefore influence the relative availabilities of N and P in the soil and hence the functioning of savanna ecosystems.

关键词： canopy sampling   phytophagous   natural enemies   pollinators  

摘要： Acacia mangium (Fabales: Fabaceae) is broadly used in restoration process of degraded lands in tropical and subtropical regions. Thus, our aim was to assess the spatial distribution of arthropods on tree crown (vertical- upper, median and lower canopy and horizontal-north, south, east and west) and leaf surfaces (adaxial and abaxial) of A. mangium trees. Phytophagous arthropods and natural enemies were quantified biweekly in 20 trees during three years. The Shannon index (H') of phytophagous insects were higher on the abaxial surface of leaves on branches facing the west side and basal thirds, while the lowest index was found on the adaxial surface of leaves on branches facing north and on trunk of A. mangium. The natural enemies and pollinators presented the highest H' indexes on the abaxial surface of leaves on branches facing north on basal thirds of A. mangium, while the lowest index values were found on the adaxial surface of leaves on branches facing the other sides. Trigona spinipes Fabricius (Hymenoptera: Apidae, Meliponinae), Aethalion reticulatum (Hemiptera: Aetalionidae) and Pentatomidae sp.1 (Hemiptera) were the most abundant and with the lowest k-dominance on different parts of A. mangium trees. Camponotus sp.2 (Hymenoptera: Formicidae), Tetragonisca angustula (Latreille) (Hymenoptera: Apidae) and Polistes sp. (Hymenoptera: Vespidae) had higher abundance and lower k-dominance. These results may be a support for programs of pest control and maintenance of natural enemies and pollinators in future plantations of A. mangium. For instance, application of biopesticides may reach better results if aimed directly to the preferred sites of target organisms, beyond minimizing possible negative effects on non-target ones.

关键词： conservation   ecology   land-use management   plant-animal interactions   tropical ecosystems  

摘要： African savannas are home to an abundant and diverse assemblage of wild herbivores, but the very grasses that sustain these wild herds also make savannas attractive to humans and their livestock We used the Kenya Long-term Exclosure Experiment to investigate the ecological effects of different combinations of native and domestic grazers. The experimental removal of large grazing mammals set into motion a cascade of consequences, beginning with the doubling in abundance of a small grazing mammal, the pouched mouse (Saccostomus mearnsi). The presence of abundant mice attracted venomous snakes such as the olive hissing snake (Psammophis mossambicus);devastated seedlings of the dominant tree (Acacia drepanolobium);and doubted the abundance of fleas, which potentially increased the risk of transmission of flea-borne pathogens. Together, these results show the potential for the loss of large mammals to have cryptic consequences for African savannas, with important and often undesirable repercussions for humans.

关键词： Animal phylogenetics   Biology and life sciences   Computational biology   Evolutionary biology   Evolutionary processes   Evolutionary systematics   Genetics   Genome analysis   Genome evolution   Genome sequencing   Genomic databases   Genomics   Mammalogy   Molecular biology   Molecular biology techniques   Phylogenetics   Research Article   Sequence analysis   Sequence databases   Sequencing techniques   Speciation   Zoology  

摘要： One of the major challenges in the analysis of closely related species, speciation and phylogeography is the identification of variable sequence markers that allow the determination of genealogical relationships in multiple genomic regions using coalescent and species tree approaches. Rodent species represent nearly half of the mammalian diversity, but so far no systematic study has been carried out to detect suitable informative markers for this group. Here, we used a bioinformatic pipeline to extract intron sequences from rodent genomes available in databases and applied a series of filters that allowed the identification of 208 introns that adequately fulfilled several criteria for these studies. The main required characteristics of the introns were that they had the maximum possible mutation rates, that they were part of single-copy genes, that they had an appropriate sequence length for amplification, and that they were flanked by exons with suitable regions for primer design. In addition, in order to determine the validity of this approach, we chose ten of these introns for primer design and tested them in a panel of eleven rodent species belonging to different representative families. We show that all these introns can be amplified in the majority of species and that, overall, 79% of the amplifications worked with minimum optimization of the annealing temperature. In addition, we confirmed for a pair of sister species the relatively high level of sequence divergence of these introns. Therefore, we provide here a set of adequate intron markers that can be applied to different species of Rodentia for their use in studies that require significant sequence variability.