关键词： Apodemus sylvaticus   Direct seeding   Direct sowing   Predator preference   Seed predation  

摘要： Direct seeding is potentially a cost-effective method for creating woodland and is particularly suited to establishing mixtures of species. Seed predation can cause poor establishment, and information on granivore preference for seed of different species is essential to evaluate relative risk and the need for control measures. We investigated consistencies in the preference of small mammals for removing seeds of 12 tree and shrub species at three sites in southern England using freely available seeds presented as single or mixed species plots. Seed preferences were modelled as preference for removal of seeds of a particular species in relation to others present in a given time period. Across-site comparison of seed preference ranks showed significant agreement, especially at each extreme of the ranks. Quercus robur and Fagus sylvatica were always ranked first or second, followed by Corylus avellana and Acer pseudoplatanus, while Crataegus monogyna and Fraxinus excelsior were ranked last;the relative position of middle ranking species varied between tests. Removal of seeds of highly preferred species was usually absolute, whereas seeds of lower ranked species were more likely to be partially removed. For most species, preference coefficients were positively related to two explanatory variates: the logarithms of whole seed and coat dry mass. The exception was Fraxinus excelsior, where preference was lower than predicted, possibly because of chemical defences. Presentation of seeds as either single or mixed species plots had no overall effect on preference ranking. The results suggest that species that produce large nuts, are more vulnerable to predation-loss and might require additional measures, such as treatment with repellents, to reduce predation risk, or might, as in the case of Q robur, be so attractive to rodents that it is unrealistic to direct sow them. The majority of the other species with smaller seed size, however, were much less susceptible to removal by

关键词： Brownian motion   character displacement   coexistence   competition   ecophylogenetics   environmental filtering   phylogenetic imbalance   Yotvata, Israel  

摘要： The distribution of traits within communities is thought to provide information on the evolutionary and ecological forces that structure community composition. Ecological character displacement (evolutionary divergence among populations of interacting species within a community), as well as community-wide character displacement (even dispersion of species traits within a community via species sorting), have been widely reported and are typically interpreted as evidence for interspecific competition. However, defining an appropriate null distribution with which to assess the observed distribution of traits within a community has proved controversial. Phylogenetic methods provide an alternative approach to evaluating community structure, but such methods also require an appropriate null and have typically overlooked the potential for evolutionary dynamics within communities. Here, we present a novel phylogenetic framework that uses evolutionary expectations to generate a simple null model of the expected distribution of traits among co-occurring species. Using a stochastic Brownian motion model of trait change, we illustrate that the expected community-wide dispersion of traits varies with phylogenetic tree shape. We then use data on body mass for mammals to evaluate the accuracy with which phylogeny can predict the empirical distribution of traits and find a strong correlation between predicted and observed trait distributions. We suggest that deviations from phylogenetic expectations may therefore provide a useful tool for evaluating the role of competition in shaping community structure. Finally, we demonstrate the utility of our approach using empirical data on body mass and a phylogeny for a small community of terrestrial mammals in Yotvata, Israel, and reveal evidence consistent with ecological and community-wide character displacement. Our method unites ecological and evolutionary approaches, and it provides a novel framework for exploring community structure.

关键词： agriculture   livestock   native pasture   nutrient enrichment   rotational grazing   woodland  

摘要： The relative effects of tree clearing, increased livestock densities and nutrient enrichment have rarely been compared across markedly different organism types, but negative effects are generally predicted. In contrast, adoption of rotational grazing is thought to benefit biodiversity in pastures but there are few supporting data. We examined the response of native plants, birds and reptiles to livestock management in south-eastern Australia. We selected 12 pairs of rotationally and continuously grazed farms. Two 1-ha plots were established in native pastures on each farm, one cleared and the second still retaining woodland tree cover. Stocking rates, fertilizer histories and landscape tree cover varied among farms. The abundance and richness of all taxa was lower in cleared pastures. The less mobile organisms (reptiles and plants) were positively correlated with tree cover at landscape scales, but only when trees were present at the plot scale. This pattern was driven by a few observations in landscapes with approximately 50% tree canopy cover. Neither bird abundance nor richness was correlated with stocking rates or nutrient enrichment, but plant richness responded negatively to both. The response of reptiles varied, declining with nutrient enrichment but positively correlated with livestock densities. These responses may be partly interpreted within the context of prior filtering of species pools through long-term grazing pressure. No taxa responded positively to rotational grazing management. We predict that reductions in livestock density and soil nutrients will directly benefit plants and less so reptiles, but not birds. Indirect benefits are predicted for birds and reptiles if management increases persistence of trees within paddocks. Although some forms of rotational grazing can increase woodland tree recruitment, rotational grazing in itself is unlikely to enhance diversity.

关键词： grazing   management   disturbance   kangaroo   Pseudomys  

摘要： The introduction of domestic cattle into systems that have had little historical grazing by large herbivores, such as the case in Australia, can lead to both direct and indirect changes in native flora and fauna. In this study, we investigate the differences in native mammal abundance between pastoral land managed for cattle production and conservation land in Australian tropical savannas. We systematically sampled 68 sites for mammals in north-eastern Queensland representing the two land tenures, which represent land with introduced stock and native herbivores present, and land where only native herbivores occur. We recorded 17 species of mammals representing five families and two functional groups (small mammals and macropods). Generalized linear mixed effects models identified that there was a significant positive relationship between increasing total ground cover and small mammal abundance and also the abundance of two species, Pseudomys desertor and P.?gracilicaudatus. We recorded a reduction in abundance on pastoral land for macropods and small mammals, and four species, M.?robustus, M.?rufus, Leggadina lakedownensis, P.?gracilicaudatus. Total ground cover and perennial grass cover was lower on pastoral land. Small mammal abundance on pastoral land was less even with increasing ground cover. Our results suggest that on pastoral land, native mammal abundance is affected and this has some relationship to ground cover changes. We recognize that there are other confounding management differences between pastoral and conservation lands such fire use, dingo baiting, and the manner of weed invasion and control that could influence mammal pattern. We conclude that conservation strategies for mammals in Australia's tropical savannas need to include a variety of land management schemes and tenures including land free from grazing by domestic livestock.

关键词： Density dependence   North-east India   Rodents   Seed predation   Seed dispersal  

摘要： Tropical tree species vary widely in their pattern of spatial dispersion. We focus on how seed predation may modify seed deposition patterns and affect the abundance and dispersion of adult trees in a tropical forest in India. Using plots across a range of seed densities, we examined whether seed predation levels by terrestrial rodents varied across six large-seeded, bird-dispersed tree species. Since inter-specific variation in density-dependent seed mortality may have downstream effects on recruitment and adult tree stages, we determined recruitment patterns close to and away from parent trees, along with adult tree abundance and dispersion patterns. Four species (Canarium resiniferum, Dysoxylum binectariferum, Horsfieldia kingii, and Prunus ceylanica) showed high predation levels (78.5-98.7%) and increased mortality with increasing seed density, while two species, Chisocheton cumingianus and Polyalthia simiarum, showed significantly lower seed predation levels and weak density-dependent mortality. The latter two species also had the highest recruitment near parent trees, with most abundant and aggregated adults. The four species that had high seed mortality had low recruitment under parent trees, were rare, and had more spaced adult tree dispersion. Biotic dispersal may be vital for species that suffer density-dependent mortality factors under parent trees. In tropical forests where large vertebrate seed dispersers but not seed predators are hunted, differences in seed vulnerability to rodent seed predation and density-dependent mortality can affect forest structure and composition.

关键词： Mallee   Cenozoic   Mammal   Paleoclimate   Paleobotany  

摘要： Mallee is an endemic Australian woodland and shrubland of semi-arid, summer-dry regions between dry woodland and desert shrubland. In other parts of the world, such as Africa and the Americas, such climatic regions support grassland ecosystems. Using Australian and African climofunctions and models gives very different reconstructions of paleoclimate (subhumid versus perhumid) and paleovegetation (woodland versus rainforest) for North American fossil mammal faunas before Cenozoic evolution of grassland ecosystems. Modern mammal faunas of Africa and Australia have different ecological spectra of taxonomic units, body size, feeding, and locomotion of species of mammals on precipitation gradients. Gradients in proportions of such categories yield transfer functions for mean annual precipitation from percent species of Artiodactyla or Macropodidae, percent species of moderately large animals (45-180 kg), percent species of arboreal mammals, and percent species of grazers. These transfer functions can be applied to fossil mammal faunas to estimate paleoprecipitation in Africa. Australia and North America. Modern transfer functions match well paleoprecipitation estimates based on depth to calcic horizons in paleosols at the same localities in Kenya and inland Australia back through the Miocene. For fossil mammal faunas of the Rocky Mountain region of North America, African transfer functions fail, but Australian transfer functions predict paleoprecipitation back to the Cretaceous-Tertiary boundary (66 Ma). Furthermore, modern mallee soils investigated in this study closely match Cretaceous to Eocene paleosols of the Rocky Mountains. Extinct mallee-like vegetation, such as pori woodlands of Kenya and cunhaka woodlands (newly defined) of the Rocky Mountains better explains the dominance of small, nocturnal, insectivorous, arboreal mammals of Paleogene and Mesozoic mammal faunas, than comparisons with African grassland or rainforest faunas. (c) 2012 Elsevier B.V. All rights

关键词： Cricetidae   Cerrado   Geometric morphometrics   Locomotory mode   Vertical stratification  

摘要： We investigated the relation between the footprint shape of the fore and hind feet of sigmodontine rodents and their levels of arboreal activity. Footprint shape was obtained by analyzing the impressions left by identified animals captured in the field after being forced to pass through ink-tracking tunnels or by pressing their previously inked feet on a paper sheet. We used geometric morphometric techniques that use superimposition of landmarks (centers of the pads) to obtain footprint shape variables, which were reduced using multivariate analysis (principal component analysis). Arboreal activity was inferred on the basis of the proportions of individuals captured in arboreal traps (1.5-2.5 m height). Regression analysis of body size and the variable that best represented the footprint shapes (first principal component-PC1) did not indicate significant allometric effects on such shapes. We did not detect any significant phylogenetic effects on the arboreal activity of the rodents, either. The results indicated that the PC1 concerning footprint shapes of ten sigmodontine rodents efficiently reflects the degree of use of arboreal strata by these animals. The species studied showed different levels of arboreal activity and their hind footprints (r(2) = 0.94) were better indicators of arboreality than the fore footprints (r(2) = 0.53). These findings suggest a likely trade off for the fore feet functions. Such functions are probably not strictly related to locomotion. Other biomechanical functions (e.g., shock absorption) and/or manipulation (e.g., food manipulation and grooming) may exert relatively greater influence on the shape of fore feet.

关键词： biodiversity   cetoniines   faunal lists   new records   protected areas   West Africa  

摘要： The cetoniine fauna of Ghana (Coleoptera: Scarabaeidae: Cetoniinae, excluding the tribes Valgini and Trichiini) is presented based on results from the Ghana Insect Project (GIP). Data from 1,571 specimens including the species and number found at each of 16 collecting sites, collecting methods, months collected, 'common' species and habitat associations are presented. The fauna now consists of 109 species in 51 genera. Previously known distributions and specimen label data are given for 31 species (including Genuchina, a subtribe of Cremastocheilini) recorded from Ghana for the first time. Comparisons with the works of Endrödi (1973, 1976) and Joly (2001) are made and several misidentifications are annotated and corrected. GIP results suggest moist evergreen/semi-deciduous forest and Guinea savanna/semi-deciduous forest are species-rich habitats. Faunal lists for four protected areas (Ankasa Resource Reserve, Atewa Range Forest Reserve, Bia National Park and Mole National Park) sampled by both the GIP and Joly (2001, 2011) are presented. PAST (Hammer et al., 2001) was used to estimate GIP inventory completeness through individual rarefaction. EstimateS (Colwell, 2009) was used to estimate total species richness using several classic nonparametric species richness estimators. Based on a data matrix of species abundances from each of the 16 GIP sites, the Chao 2 estimator stabilizes at ca. 113 taxa, and the jackknife 2 estimator at ca. 130 taxa. Richness estimates based on a broader, incidence-based matrix from all three sources GIP, Endrödi (1973, 1976) and Joly (2001, 2011) were: Chao 2 = 153, jackknife 1 = 157, jackknife 2 = 173. Additional sampling in under-sampled habitats such as wet and moist evergreen forest and Guinea savanna, and during the dry and early wet seasons should yield additional species. [ABSTRACT FROM AUTHOR]

关键词： Anti-predator behavior   Group living   Impala   Patch quality   Vigilance   Visibility  

摘要： Vigilance allows individuals to escape from predators, but it also reduces time for other activities which determine fitness, in particular resource acquisition. The principles determining how prey trade time between the detection of predators and food acquisition are not fully understood, particularly in herbivores because of many potential confounding factors (such as group size), and the ability of these animals to be vigilant while handling food. We designed a fertilization experiment to manipulate the quality of resources, and compared awareness (distinguishing apprehensive foraging and vigilance) of wild impalas () foraging on patches of different grass height and quality in a wilderness area with a full community of predators. While handling food, these animals can allocate time to other functions. The impalas were aware of their environment less often when on good food patches and when the grass was short. The animals spent more time in apprehensive foraging when grass was tall, and no other variable affected apprehensive behavior. The probability of exhibiting a vigilance posture decreased with group size. The interaction between grass height and patch enrichment also affected the time spent in vigilance, suggesting that resource quality was the main driver when visibility is good, and the risk of predation the main driver when the risk is high. We discuss various possible mechanisms underlying the perception of predation risk: foraging strategy, opportunities for scrounging, and inter-individual interference. Overall, this experiment shows that improving patch quality modifies the trade-off between vigilance and foraging in favor of feeding, but vigilance remains ultimately driven by the visibility of predators by foragers within their feeding patches.