关键词： East Africa   Paleoecology   Hominin evolution   Herbivore diet   Plio-Pleistocene   Malawi  

摘要： The Plio-Pleistocene expansion of Eastern Africa savanna ecosystems was a major driver for morphological and behavioral innovations in hominin evolution. Most evidence for hominin ecosystem reconstructions originates from the Eastern Rift in today's Somali-Masai Endemic Zone. We provide stable carbon (delta C-13) and oxygen (delta O-18) isotope data from 22 bovid, equid, suid, hippopotamid and elephant teeth from the southern part of the East African Rift and supplement these by 8180 values of present-day meteoric water. This region (Karonga Basin, Malawi) hosts remains of Homo rudolfensis and Paranthropus boisei. It is situated between hominin-bearing sites in Eastern and Southern Africa and therefore fills an important geographical gap for hominin evolution. Tooth enamel delta C-18 and 8180 data of 14 large-bodied mammalian herbivore species from Units 2 and 3 (ca. 4.3 to 0.6 Ma) in the Chiwondo Beds provide information about foraging strategies and vegetation patterns. Our stable isotope data reflect C-3-dominated ecosystems that permitted access to open C-4-environments for migratory mammals. Many analyzed taxa show evidence for mixed diets with high abundances of C-3-biomass consumption;only selected bovids were specialized grazers. delta O-18 of present-day meteoric water reflects rainfall amount and seasonality, elevation, and lake evaporation. 6180 values of Karonga Basin herbivore enamel are generally low and cover values similar to present-day drinking water, indicating both, evaporated and freshwater sources. Comparison of delta C-13 values from the Karonga Basin with other Eastern African herbivore communities reveals significant differences in dietary patterns with much more generalized mixed C-3/C-4, and pure C-3 feeding behaviors in the Malawi Rift. Similarly, enamel 6180 values are lower than in most Plio-Pleistocene Eastern African herbivores, suggesting more humid conditions. Collectively, our data support models in which early hominin foraging act

关键词： GENOMICS   TREE of life   ZOOLOGISTS   DATA quality   PHYLOGENY  

摘要： Providing consistent resolution for the animal tree of life is a major goal of animal systematists and a desire of every zoologist. Towards this goal, many major nodes have been successfully resolved. However, some major controversies and poorly resolved deep nodes still remain. Here, I discuss some of these controversies (e.g. whether Ctenophora or Porifera is sister group to all other animals), clarify others (e.g. the position of Xenacoelomorpha) and identify major clades that still require resolution. But most importantly, a discussion about the possible conflict in some of these nodes and the relation to the nature of phylogenomic data are provided by exploring the meaning of total support in phylogenomic analyses, highlighting cases in which a data set can provide total support for contradictory nodes. Finally, our efforts should focus on generating genomic data for key candidate taxa, such as the large disparity of undescribed placozoans, which may in the end add to the current data quantity, the quality of data needed to resolve the base of the animal tree.

关键词： Amniotes   Animal types   Animals   Aquatic environments   Biology and life sciences   Bodies of water   Community ecology   Conservation science   Earth sciences   Ecology   Ecology and environmental sciences   Ecosystems   Elephants   Freshwater environments   Habitats   Herbivory   Hydrology   Mammals   Marine and aquatic sciences   Organisms   Plant ecology   Plant science   Plant-animal interactions   Research Article   Rivers   Surface water   Trophic interactions   Vertebrates   Wildlife   Zoology  

摘要： An understanding of the habitat selection patterns by wild herbivores is critical for adaptive management, particularly towards ecosystem management and wildlife conservation in semi arid savanna ecosystems. We tested the following predictions: (i) surface water availability, habitat quality and human presence have a strong influence on the spatial distribution of wild herbivores in the dry season, (ii) habitat suitability for large herbivores would be higher compared to medium-sized herbivores in the dry season, and (iii) spatial extent of suitable habitats for wild herbivores will be different between years, i.e., 2006 and 2010, in Matetsi Safari Area, Zimbabwe. MaxEnt modeling was done to determine the habitat suitability of large herbivores and medium-sized herbivores. MaxEnt modeling of habitat suitability for large herbivores using the environmental variables was successful for the selected species in 2006 and 2010, except for elephant (Loxodonta africana) for the year 2010. Overall, large herbivores probability of occurrence was mostly influenced by distance from rivers. Distance from roads influenced much of the variability in the probability of occurrence of medium-sized herbivores. The overall predicted area for large and mediumsized herbivores was not different. Large herbivores may not necessarily utilize larger habitat patches over medium-sized herbivores due to the habitat homogenizing effect of water provisioning. Effect of surface water availability, proximity to riverine ecosystems and roads on habitat suitability of large and medium-sized herbivores in the dry season was highly variable thus could change from one year to another. We recommend adaptive management initiatives aimed at ensuring dynamic water supply in protected areas through temporal closure and or opening of water points to promote heterogeneity of wildlife habitats.

关键词： Africa   Bovidae   coevolution   mammalian herbivory   savanna  

摘要： Savannas first began to spread across Africa during the Miocene. A major hypothesis for explaining this vegetation change is the increase in C-4 grasses, promoting fire. We investigated whether mammals could also have contributed to savanna expansion by using spinescence as a marker of mammal herbivory. Looking at the present distribution of 1,852 tree species, we established that spinescence is mainly associated with two functional types of mammals: large browsers and medium-sized mixed feeders. Using a dated phylogeny for the same tree species, we found that spinescence evolved at least 55 times. The diversification of spiny plants occurred long after the evolution of Afrotherian proboscideans and hyracoids. However, it is remarkably congruent with diversification of bovids, the lineage including the antelope that predominantly browse these plants today. Our findings suggest that herbivore-adapted savannas evolved several million years before fire-maintained savannas and probably, in different environmental conditions. Spiny savannas with abundant mammal herbivores occur in drier climates and on nutrient-rich soils, whereas fire-maintained savannas occur in wetter climates on nutrient-poor soils.

关键词： Live-dead agreement   Conservation paleobiology   Taphonomy   Carbonate lagoon   Great Barrier Reef  

摘要： Reef-associated sediments accumulate over time recording the history of biological communities. The agreement between live and dead assemblages has been extensively studied, because discrepancies between the two can reveal taphonomic bias, anthropogenic impact, and/or a decrease in temporal resolution of dead assemblages to centennial scales (i.e., time averaging). Given the potential of sedimentary assemblages to provide temporal perspectives on the history of modern communities, assessments of live-dead agreement in reef mollusk assemblage composition are necessary and timely for understanding rapid environmental change. One Tree Reef (OTR) (southern Great Barrier Reef, Australia) has had very little direct anthropogenic influence over the past four decades, making it a good system for focusing on taphonomic patterns. Live (n = 1335) and dead (n = 6919) molluscan assemblages were collected from three shallow (6 m) carbonate soft-sediment lagoons. Diversity and evenness metrics indicated no significant difference between the live and dead assemblages, and dead assemblage rank order abundance explains 82% of that of the live assemblage. Differences in composition were largely due to sample size, the low probability of sampling rare species and to a lesser degree differences in skeletal durability. Taphonomic factors were responsible for less than 20% of the differences in species composition between live and dead shell assemblages. The live molluscan assemblage sampled was similar to the live assemblage sampled 30 years ago. Given that time averaging is approximately 19 years in the OTR lagoon, we conclude that the composition of the living assemblage has remained largely unchanged for the last 30 years. These findings indicate that dead assemblages preserved in shallow, fully carbonate environments primarily reflect the composition of the original source communities, making them useful to identify recent changes in coral reef areas where anthropogenic impacts are p

关键词： abiotic factors   biotic factors   climate   decomposition   nutrient cycling   termites  

摘要： Termites have a large influence on ecosystem functioning. Understanding what drives termite activity patterns improves understanding of nutrient cycling, productivity, and heterogeneity in savannas. We present a mechanistic framework that relates the interactive effects of rainfall, grassland structure, large herbivore presence, and soil factors to termite activity. To test this framework, we used grass litterbags to monitor termite activity at ten sites across Hluhluwe-iMfolozi Park, South Africa. We assessed the effects of abiotic and biotic factors on termite activity at two scales: the large (landscape) scale, variation in bait removal among 300 m(2) plots that were distributed across the park and at the small (within-plot) scale (1-300 m(2)). Half of our sites were located inside large herbivore exclosures to test for the effect of mammalian herbivore presence. At the landscape scale, termite grass removal declined towards higher rainfall and in the presence of mammalian herbivores. Removal did not depend on soil factors. At the small scale, removal declined with increasing grass height, particularly in the 1 m surrounding the bait bag. Resource quality did not affect bait removal. We suggest that competition for forage drives the negative effect of mammalian herbivores on termites, whereas lower bait removal in taller swards may be due to direct negative effects from rainfall, fire and/or competition with free-living microbes. Ultimately, we suggest that the impact of termites on nutrient cycling is most pronounced when abiotic (rainfall) and biotic conditions (mammalian herbivory) limit grass removal by fire and decomposition by free-living microbes.

关键词： Exclosures   Herbaceous vegetation   Herbivory   Neighbourhoods   Small mammals   Temperate deciduous forests  

摘要： Question: Small mammals are important consumers of tree seeds in forests worldwde. Few studies, however, have addressed *** of small mammals as consumers of herbaceous species in tile forest understorey. Local neighbourhood -scale variation in canopy tree composition has strong effects on resource availability for understorey plants, but can also influence the distribution, abundance and foraging behaviour of small mammals, primarily through spatial and temporal variation in seed rain. In this study we examine the direct and indirect effects of canopy tree neighbourhoods and herbivory by small mammals on the diversity, abundance and flowering of herbaceous species in a temperate forest. Location and Methods: In 1994 we established 36 1 rn x 2 m fenced small mammal exclosures, paired with similar-sized control plots, under the major canopy tree species found at Great Mountain Forest, in Norfolk, CT, US. Results: When re-sampled in 2005, after 10 yrs of small mammal exclusion, the abundance of herbaceous plants had increased inside the exclosures (F = 5.005, df = 1,38, P = 0.031), as did the proportion of plants flowering cc: 2.11, df :cc- 60, P = 0.039). However, species richness and Shannon Wiener diversity (fr) were similar inside and outside of exclosures. At one site the identity of the canopy tree species did impact species richness (F 4.494, df = 5,18, P = 0.008), independent of exclosure. Plots under Praxinus americana (white ash) had the highest species richness (*** of species = 7.5) while the lowest diversity was found in plots under Tsuga canadensis (Eastern hemlock;average number of species = 2.25) and Quercus ruhra (non-lie:J-1i red oak;average number of species = 1.5). Conclusions: The results demonstrate that small mammal herbivores can directly affect the abundance and reproduction of herbaceous species, and that local conditions (such as the surrounding canopy tree neighbourhood) can also play direct and indirect roles in Ilse mair

关键词： Arthropods   Fossils   Phylogeny   Divergence times  

摘要： Fossil age data and molecular sequences are increasingly combined to establish a timescale for the Tree of Life. Arthropods, as the most species-rich and morphologically disparate animal phylum, have received substantial attention, particularly with regard to questions such as the timing of habitat shifts (e.g. terrestrialisation), genome evolution (e.g. gene family duplication and functional evolution), origins of novel characters and behaviours (e.g. wings and flight, venom, silk), biogeography, rate of diversification (e.g. Cambrian explosion, insect coevolution with angiosperms, evolution of crab body plans), and the evolution of arthropod microbiomes. We present herein a series of rigorously vetted calibration fossils for arthropod evolutionary history, taking into account recently published guidelines for best practice in fossil calibration. These are restricted to Palaeozoic and Mesozoic fossils, no deeper than ordinal taxonomic level, nonetheless resulting in 80 fossil calibrations for 102 clades. This work is especially timely owing to the rapid growth of molecular sequence data and the fact that many included fossils have been described within the last five years. This contribution provides a resource for systematists and other biologists interested in deep-time questions in arthropod evolution. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Aestivation   Desiccation   Hydroperiod   Refugia   Riparian vegetation   Temperature  

摘要： Climate change is causing prolonged drying in many seasonal wetlands, including urban wetlands, potentially affecting aquatic invertebrates that take refuge in wetland sediment during dry periods and thereby threatening wetland biodiversity. We collected sediment from two habitats: open water (OW) and fringing trees (FT), in eight urban wetlands after seasonal inundation had ended. Both habitats are inundated during winter-spring and dry in summer-autumn. Each sediment sample was divided into subsamples. One set of subsamples were inundated in the laboratory to test the hypothesis that emerging invertebrate assemblages would differ between OW and FT sediments. Another set of subsamples was dried, stored for a year, and inundated to test the hypothesis that prolonged drying would reduce the abundance and taxa richness of emerging invertebrates. The composition of emerging invertebrate assemblages differed between habitats, with more amphibious species found in FT sediment. Invertebrate responses to prolonged drying and storage varied among species: for some, effects depended on habitat type, while others delayed emergence or showed no response. Microcrustacean abundance was unaffected by drying, suggesting that their productivity during refilling may resist drier water regimes. Surface temperatures of dry sediment are cooler beneath FT, and this sediment has higher organic matter, holds more water and is less dense than OW sediment;and FT sediment remained cooler than OW sediment in the laboratory, despite the absence of shading. Fringing trees may therefore provide a refuge for some freshwater invertebrates relying on dormant stages in the sediment to survive drying in urban wetlands.

关键词： Cerrado   diversity   herbivory   leaf shelter   Malpighiaceae  

摘要： 1. Variation in plant phenology allows plants to escape from herbivory. Insect herbivores manipulate their host plants by producing shelters, which they inhabit, and are protected against natural enemies and/or unfavourable environmental conditions. Environmental modifications induced by living organisms are characterised as ecosystem engineering. 2. In the Brazilian savanna, the interaction between the Malpighiaceae shrub, Byrsonima intermedia, and its main herbivore, the caterpillar Cerconota achatina, a shelter-building organism, was studied. 3. It was focused on whether the phenological development of the host plant affects the caterpillars' infestation, and whether C. achatina acts as an ecosystem engineer by building shelters. All plant variables (number of leaves, flowers, buds, fruits and herbivores) were measured fortnightly. Phenological data were correlated with climatic information. The impact of the caterpillars acting as ecosystem engineers was measured experimentally. 4. Infestation levels of C. achatina covaried with the phenology of their host plant B. intermedia. It suggests that plant phenology might be an important factor in determining the abundances of this ecosystem engineer species.