Within and Among Patch Variability in Patterns of Insect Herbivory Across a Fragmented Forest Landscape

Fragmentation changes the spatial patterns of landscapes in ways that can alter the flow of materials and species; however, our understanding of the consequences of this fragmentation and flow alteration for ecosystem processes and ecosystem services remains limited. As an ecological process that affects many ecosystem services and is sensitive to fragmentation, insect herbivory is a good model system for exploring the role of fragmentation, and the resulting spatial patterns of landscapes, in the provision of ecosystem services. To refine our knowledge of how changes in landscape pattern affect insect herbivory, we quantified the combined influence of among patch (patch area and patch connectivity) and within patch (location within patch; canopy, edge, interior) factors on amounts of insect herbivory in a fragmented forest landscape. We measured herbivory in 20 forest patches of differing size and connectivity in southern Quebec (Canada). Within each patch, herbivory was quantified at the interior, edge, and canopy of sugar maple trees during the spring and summer of 2011 and 2012. Results show that connectivity affects herbivory differently depending on the location within the patch (edge, interior, canopy), an effect that would have gone unnoticed if samples were pooled across locations. These results suggest considering structure at both the patch and within patch scales may help to elucidate patterns when studying the effects of fragmentation on ecosystem processes, with implications for the services they support.     

Changes in the Ostracod Assemblages of the Northeastern Black Sea Shelf during the Late Pleistocene and Holocene

Paleontological Journal - Distribution of 57 ostracod species is investigated in the Quaternary sediment samples from the borehole RBH-16, drilled at the north-eastern Black Sea shelf edge off the...     

On Permian and Triassic insect faunas in relation to biogeography and the Permian-Triassic crisis

The taxonomic diversity dynamics of pterygote insects in the Permian and Triassic at the family/age level are considered. Different metrics of taxonomic diversity are compared. Biogeographic and taphonomic aspects of changes in the composition of insect faunas in the Permian and about the P-T transition are discussed. Some changes in the Permian insect faunas are of a biogeographic nature and do not indicate global changes in diversity. Insects with aquatic immatures were rather common in the Permian and Early Triassic, but these immatures are well represented in only few localities.     

Evolution of the Permian and Triassic tetrapod communities of Eastern Europe

The Permo-Triassic terrestrial and freshwater tetrapod communities of Eastern Europe are reconstructed as food-webs. The Late Permian theriodont-dinocephalian community (Ocher, Mezen, Isheyevo) changes to a latest Permian theriodont-pareiasaur community (North Dvina, Vyazniki). After a major extinction, the Triassic thecodontian-dicynodont communities appear, a lystrosaurid one in the Early Triassic (Lower and ?Upper Vetluga), and a kannemeyerid one in the later Early Triassic (?Yarenga) and the Mid Triassic (Donguz, Bukobay). Similar stages are represented in the evolution of aquatic communities: the Late Permian temnospondyl community (Ocher, Isheyevo), the latest Permian chroniosuchian one (North Dvina, Vyazniki), the Lower and Middle Triassic new temnospondyl one (from Vetluga to Bukobay). The faunal changes in Eastern Europe are mirrored in other parts of the world, although there are some endemic Russian forms.     

Facies patterns of a tectonically-controlled Upper Triassic platform-slope carbonate depositional system (Carnian Prealps, Northeastern Italy)

Summary Upper Triassic (Middle-Upper Norian) shallow-water carbonates of the Dolomia Principale and its deep-water counterparts (Forni Dolomite) have been studied in the Carnian Prealps (northeastern Italy). The Dolomia Principale was a storm-dominated carbonate platform; in the Mt. Pramaggiore area, along a well-preserved 3.5 km-long platform-to-basin transition, the inner platform facies of the Dolomia Principale, characterized by m-scale shallowing upward cycles, give way seaward to open marine storm-dominated shallow subtidal lagoon deposits with frequent hardgrounds and evidence of microbial stabilization of the bottom sediment. The margin of the Dolomia Principale platform was colonized by meter-scale stromatolites and serpulid-microbial mounds that thrived due to the local highly stressed environment, characterized by drastic salinity fluctuations and turbid waters, that excluded the Upper Triassic coral-sponge communities. The Forni Dolomite slope-basin complex was characterized by an upper slope facies with debris flows, megabreccias, turbidites and serpulid-microbial mounds. The lower slope and basinal facies show thinning and fining trends. After restoring the original geometry of the slope, the depositional angles of the clinoforms range between 11 and 36 degrees, reflecting closely the coarse-grained character of the Forni Dolomite slope complex, which can be interpreted as a slope apron that, as a model, can be extended to steeply inclined carbonate slopes. The onset of synsedimentary extensional tectonics at the Middle-Late Norian boundary affected the platform-slope depositional system via: 1) localized inner platform collapses and the formation of an intraplatform anoxic depression at Mt. Valmenone, 2) a switch from platform lateral progradation during the Middle Norian to vertical aggradation in the Late Norian, reflected in an increase in platform relief, steeper foreslope angles and coarser-grained slope facies, and 3) controlling the spatial orientation of the margin of the Dolomia Principale.     

Permian and Triassic Therocephals (Eutherapsida) of Eastern Europe

Cranial morphology of Permian and Triassic Therocephalia of Eastern Europe is revised. The Therocephalia are regarded as an order of the subclass Eutherapsida of the class Theromorpha. Phylogenetic relationships are reconsidered and a tentative taxonomic scheme of the order is proposed. Biomorph evolution of East European Therocephalia from the Middle Permian to the Middle Triassic are discussed.     

Focus on Metabolism: Alteration of Plant Primary Metabolism in Response to Insect Herbivory

Plants in nature, which are continuously challenged by diverse insect herbivores, produce constitutive and inducible defenses to reduce insect damage and preserve their own fitness. In addition to inducing pathways that are directly responsible for the production of toxic and deterrent compounds, insect herbivory causes numerous changes in plant primary metabolism. Whereas the functions of defensive metabolites such as alkaloids, terpenes, and glucosinolates have been studied extensively, the fitness benefits of changes in photosynthesis, carbon transport, and nitrogen allocation remain less well understood. Adding to the complexity of the observed responses, the feeding habits of different insect herbivores can significantly influence the induced changes in plant primary metabolism. In this review, we summarize experimental data addressing the significance of insect feeding habits, as related to herbivore-induced changes in plant primary metabolism. Where possible, we link these physiological changes with current understanding of their underlying molecular mechanisms. Finally, we discuss the potential fitness benefits that host plants receive from altering their primary metabolism in response to insect herbivory.Plants in nature are subject to attack by a wide variety of phytophagous insects. Nevertheless, the world is green, and most plants are resistant to most individual species of insect herbivores. To a large extent, this resistance is due to an array of toxic and deterrent small molecules and proteins that can prevent nonadapted insects from feeding. Although many plant defenses are produced constitutively, others are inducible (i.e. defense-related metabolites and proteins that are normally present at low levels become more abundant in response to insect feeding). Inducible defense systems, which allow more energy to be directed toward growth and reproduction in the absence of insect herbivory, represent a form of resource conservation. Well-studied examples of inducible plant defenses include the production of nicotine in tobacco (Nicotiana tabacum; Baldwin et al., 1998), protease inhibitors in tomato (Solanum lycopersicum; Ryan, 2000), benzoxazinoids in maize (Zea mays; Oikawa et al., 2004), and glucosinolates in Arabidopsis (Arabidopsis thaliana; Mewis et al., 2005). Additionally, herbivore-induced plant responses can include the production of physical defenses such as trichomes or thickened cell walls that can make insect feeding more difficult. Some plant defensive metabolites are highly abundant, suggesting that their biosynthesis can have a significant effect on overall plant metabolism. For instance, benzoxazinoids can constitute 1% to 2% of the total dry matter of some Poaceae (Zúñiga et al., 1983), and up to 6% of the nitrogen in herbivore-induced Nicotiana attenuata can be devoted to nicotine production (Baldwin et al., 1998).In addition to the herbivore-induced production of physical and chemical defenses, numerous changes in plant primary metabolism occur in response to insect herbivory. Among other observed effects, these can include either elevated or suppressed photosynthetic efficiency, remobilization of carbon and nitrogen resources, and altered plant growth rate. However, although the defensive value of induced toxins such as nicotine, terpenes, benzoxazinoids, and glucosinolates is clear, it is sometimes more difficult to elucidate the function of herbivore-induced changes in plant primary metabolism. Insects may also manipulate plant primary metabolism for their own benefit, making it challenging to determine whether the observed changes are actually a plant defensive response.Here, we describe commonly observed changes in plant primary metabolism, focusing on carbohydrates and nitrogen, and discuss their possible functions in plant defense against insect herbivory. There are large differences among published studies involving different plant-herbivore combinations, and no universal patterns in the herbivory-induced changes in plant primary metabolism. Therefore, we also discuss how the potential benefits can depend on the tissue that is being attacked, the extent of the tissue damage, and the type of insect herbivore that is involved in the interaction.     

Exine morphology and ultrastructure of Duplicisporites from the Triassic of Italy

A morphological study of dispersed Circumpolles pollen grains from the Upper Triassic of the Southern Alps has been initiated with the genus Duplicisporites. Individual pollen grains were studied by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Seen with SEM the pollen surface is finely verrucate with low verrucae of different sizes. A sub‐equatorial continuous rimula is clearly visible. The proximal trilete scar is small and indistinct. TEM images reveal a bi‐layered exine. The ectexine is formed by numerous small, closely packed, granulae subdivided by irregularly‐spaced cavities. In the region of the subequatorial canal, the ectexine becomes thinner, about 1/3 of the usual thickness. At places, the ectexine is slightly separated from the underlying endexine. The endexine is prominent and significantly darker than the ectexine. It is homogeneous and of constant thickness. On the basis of its older age, with respect to Classopollis, the present ultrastructural dataset provides information on the possible origin of cheirolepidiaceous‐type morphology.     

Spatial and Temporal Patterns in Assemblages of Temperate Reef Fish

SYNOPSIS. For reef fish in temperate marine regions, such componentsof local assemblage diversity (i.e., within a reef) as speciesrichness, total fish density, and rank order of abundance canremain relatively constantthrough time. Long-term data (17 years)for assemblages on 2 reefs in Southern California revealed that,despite high turnover in rare species, overall species richnesswas affected only moderately by major oceanographicdisturbances.This resilience of the assemblage is in marked contrast to hightemporal variation in densities exhibited by many local populationsof individual species, and it suggests that measurements ofdiversity to indicate status of an assemblage should be usedwith caution. Here we consider various processes and factors,together with the spatial and temporal scales over which theyoperate, that can influence local diversity (and its estimation)of reef fishes. Mechanisms that can "buffer" local diversityof reef fishes include dispersal of young that inter-connectssubpopulations, high "inertia" in relative abundance and populationstructures (especially for long-lived species), and broad ecologicalrequirements of many species. These considerations suggest thatthe effect of disturbances on local diversity of reef fisheswill depend in part on the magnitude, duration, frequency andspatial scale of the perturbation. While long-term data arefew, available information suggests that, due to life historycharacteristics of the fish and the spatial and temporal scalesat which disturbances are likely to occur, assemblages of temperatemarine reef fish might be relatively resilient to environmentalperturbations     

Effects of Nitrogen Deposition on Insect Herbivory: Implications for Community and Ecosystem Processes

The deposition of anthropogenically fixed nitrogen (N) from the atmosphere onto land and plant surfaces has strong influences on terrestrial ecosystem processes. Although recent research has expanded our understanding of how N deposition affects ecosystems directly, less attention has been directed toward the investigation of how N deposition may affect ecosystems indirectly by modifying interactions among organisms. Empirical evidence suggests that there are several mechanisms by which N deposition may affect interactions between plants and insect herbivores. The most likely mechanisms are deposition-induced shifts in the quality and availability of host plant tissues. We discuss the effects of N deposition on host plant chemistry, production, and phenology, and we review the evidence for the effects of N deposition on insect herbivores at the individual, population, and community levels. In general, N deposition has positive effects on individual insect performance, probably due to deposition-induced improvements in host plant chemistry. These improvements include increased N and decreased carbon-based defensive compound concentrations. The evidence to date suggests that N deposition may also have a positive effect on insect populations. These effects may have considerable ecological, as well as economic consequences if the rates of herbivory on economically important timber species continue to increase. Deposition-induced changes in plant–herbivore relationships may affect community and ecosystem processes. However, we predict that the larger-scale consequences of interactions between N deposition and herbivory will vary based on site-specific factors. In addition, interactions between N deposition and other global-scale changes may lead to nonadditive effects on patterns of herbivory.     

Battenizyga, a new Early Triassic gastropod genus with a discussion of the caenogastropod evolution at the Permian/Triassic boundary

Battenizyga, a new Early Triassic gastropod genus from the Moenkopi Formation of Utah, is described and the speciesAnoptychia eotriassica Batten & Stokes, 1986 is placed in it. The new genus has an axially ribbed planktonic larval shell and a teleoconch with an angulated periphery. This character combination is unknown from the Palaeozoic. Therefore,Battenizyga represents additional evidence that recovery from the end-Permian mass extinction was connected with a faunal turnover. Additionally, the extinction of diverse Palaeozoic groups of the Caenogastropoda in the Permian (e.g., the Pseudozygopleuridae) suggest a turnover. All caenogastropod genera that hold Early Triassic species, have post-Palaeozoic type species and most were not reported from the Palaeozoic. This corroborates the view that there was an intense faunal turnover within the Caenogastropoda.Battenizyga is probably a caenogastropod that is closely related to the superfamily Zygopleuroidea which is abundant in the late Palaeozoic and early Mesozoic.      

To the Revision of Freshwater Permian and Triassic Ostracods of the Genus Gerdalia Belousova, 1961

Paleontological Journal - Partial revision of the Permian–Triassic freshwater ostracod genus Gerdalia Belousova, 1961 is performed. The genus is shown to be a collective group. The holotype...     

The Robustness of Plant-Pollinator Assemblages: Linking Plant Interaction Patterns and Sensitivity to Pollinator Loss

Most flowering plants depend on pollinators to reproduce. Thus, evaluating the robustness of plant-pollinator assemblages to species loss is a major concern. How species interaction patterns are related to species sensitivity to partner loss may influence the robustness of plant-pollinator assemblages. In plants, both reproductive dependence on pollinators (breeding system) and dispersal ability may modulate plant sensitivity to pollinator loss. For instance, species with strong dependence (e.g. dioecious species) and low dispersal (e.g. seeds dispersed by gravity) may be the most sensitive to pollinator loss. We compared the interaction patterns of plants differing in dependence on pollinators and dispersal ability in a meta-dataset comprising 192 plant species from 13 plant-pollinator networks. In addition, network robustness was compared under different scenarios representing sequences of plant extinctions associated with plant sensitivity to pollinator loss. Species with different dependence on pollinators and dispersal ability showed similar levels of generalization. Although plants with low dispersal ability interacted with more generalized pollinators, low-dispersal plants with strong dependence on pollinators (i.e. the most sensitive to pollinator loss) interacted with more particular sets of pollinators (i.e. shared a low proportion of pollinators with other plants). Only two assemblages showed lower robustness under the scenario considering plant generalization, dependence on pollinators and dispersal ability than under the scenario where extinction sequences only depended on plant generalization (i.e. where higher generalization level was associated with lower probability of extinction). Overall, our results support the idea that species generalization and network topology may be good predictors of assemblage robustness to species loss, independently of plant dispersal ability and breeding system. In contrast, since ecological specialization among partners may increase the probability of disruption of interactions, the fact that the plants most sensitive to pollinator loss interacted with more particular pollinator assemblages suggest that the persistence of these plants and their pollinators might be highly compromised.     

Formal system of dispersed leaf cuticles of pteridosperms (Peltaspermaceae) from the Permian and Triassic of the Russian platform

A formal system of dispersed leaf cuticles of peltaspermaceous pteridosperms is proposed. It is based on the epidermal groups established on the basis of correlation between epidermal features and leaf morphology of peltasperms.