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This paper proposes a model checking method for a trajectory tracking controller for a flapping wing micro-air-vehicle (MAV) under disturbance. Due to the coupling of the continuous vehicle dynamics and the discrete guidance laws, the system is a hybrid system. Existing hybrid model checkers approximate the model by partitioning the continuous state space into invariant regions (flow pipes) through the use of reachable set computations. There are currently no efficient methods for accounting for unknown disturbances to the system. Neglecting disturbances for the trajectory tracking problem underestimates the reachable set and can fail to detect when the system would reach an unsafe condition. For linear systems, we propose the use of the H-infinity norm to augment the flow pipes and account for disturbances. We show that dynamic inversion can be coupled with our method to address the nonlinearities in the flapping-wing control system. [ABSTRACT FROM AUTHOR]

In this paper different approaches to elucidate ecosystem dynamics are described, illustrated and interrelated. Ecosystem development is distinguished into two separate sequences, a complexifying phase which is characterized by orientor optimization and a destruction based phase which follows disturbances. The two developmental pathways are integrated in a modified illustration of the ˵adaptive cycle″. Based on these fundamentals, the recent definitions of resilience, adaptability and vulnerability are discussed and a modified comprehension is proposed. Thereafter, two case studies about wetland dynamics are presented to demonstrate both, the consequences of disturbance and the potential of ecosystem recovery. In both examples ecosystem integrity is used as a key indicator variable. Based on the presented results the relativity and the normative loading of resilience quantification is worked out. The paper ends with the suggestion that the features of adaptability could be used as an integrative guideline for the analysis of ecosystem dynamics and as a well-suited concept for ecosystem management. [ABSTRACT FROM AUTHOR]

Recent studies on earthworm invasion of North American soils report dramatic changes in soil structure, nutrient dynamics and plant communities in ecosystems historically free of earthworms. However, the direct and indirect impacts of earthworm invasions on animals have been largely ignored. This paper summarizes the current knowledge on the impact of earthworm invasion on other soil fauna, vertebrates as well as invertebrates. Earthworm invasions can have positive effects on the abundance of other soil invertebrates, but such effects are often small, transient, and restricted to habitats with harsh climates or a long history of earthworm co-occurrence with other soil invertebrates. Middens and burrows can increase soil heterogeneity and create microhabitats with a larger pore size, high microbial biomass, and microclimates that are attractive to microand mesofauna. Under harsh climatic conditions, the aggregates formed by earthworms may increase the stability of soil microclimates. Positive effects can also be seen when comminution and mucus secretion increase the palatability of unpalatable organic material for microorganisms which are the main food of most micro- and mesofaunal groups. For larger invertebrates or small vertebrates, invasive earthworms may become important prey, with the potential to increase resource availability. In the longer-term, the activity of invading earthworms can have a strong negative impact on indigenous faunal groups across multiple trophic levels. Evidence from field and laboratory studies indicates that the restructuring of soil layers, particularly the loss of organic horizons, physical disturbance to the soil, alteration of understory vegetation, and direct competition for food resources, lead directly and indirectly to significant declines in the abundance of soil micro- and mesofauna. Though studies of invasive earthworm impacts on the abundance of larger invertebrates or vertebrates are generally lacking, recent evidence suggests that reduced abundance of small soil fauna and alteration of soil microclimates may be contributing to declines in vertebrate fauna such as terrestrial salamanders. Preliminary evidence also suggests the potential for earthworm invasions to interact with other factors such as soil pollution, to negatively affect vertebrate populations. [ABSTRACT FROM AUTHOR]

For fast and convenient access to the environment based on the geomorphic characteristics of camouflage regional model for the complexity of topography, this article analyzes a variety of terrain modeling method΄s advantages and limitations, discussed a variety of modeling methods in the set up of the study of basic on the hybrid modeling method and the integrated use of research results to generate the details of the existing landform characteristics can be controlled on all-terrain results. Generate local terrain adaptive modeling method, as a regional model disguised form with the local terrain topography of the region to adapt to a good camouflage effect. [ABSTRACT FROM AUTHOR]

In the ‘Wooden Age’ nearly everything involved wood at some point in its production. There was no iron without charcoal or wood for pit-props and pickaxe handles, no glass or soap without potash, no transport of anything above a minimal bulk without carts, sledges, wagons and rivercraft. The previous three chapters have identified the kinds of wood that people needed, the uses to which woodland was generally put, and the manner in which such flows were regulated. This chapter will develop these themes further, with two areas particularly in mind. One is the spatial distribution of the production and consumption of wood, the form of exchange involved, and the identification of what ecologists would call ‘sources’ (points of origin) and ‘sinks’ (points of consumption) of the resource. Tracing these patterns over time will allow us to address questions of the nature of economic development, and the causes of landscape and environmental change. Understanding these processes, however, requires more than the mapping of material flows. It is also essential to comprehend how people thought about such movements and exchanges in a world strongly shaped by both institutional imperatives, and a straightforward fear of suffering, illness and mortality. In the cold winter of 1743, for example, the ducal authorities attempted to enforce the mandatory limit of two ‘wood days’ for cutting and collection in the Vorstwald of Bietigheim. But the snow lay deep on the ground that December, and local authorities objected. [ABSTRACT FROM AUTHOR]

The conceptual framework that I have attempted to develop in this volume strives to be one adequate to the task of understanding how the state and the material world intersected, and to enable us to describe and explain what might be implied by early modern society living in the ‘wooden age’. One hopes the reader has been convinced of the degree to which early modern history is intertwined with what is usually considered the realm of botanists or environmental scientists in a ‘historical ecology’. The growth rates of plants to a large degree determined available energy supplies, setting the parameters for economic development. The high rate of friction of wooden surfaces against earthen or, very rarely, paved roads contributed to high transport costs and impeded exchange. The relatively lesser friction, and the continual downward surge born of gravity, gave a comparative advantage to those who could bear their wooden loads on waterways. These things have perhaps been so evident to historians, that they have rarely attempted to investigate their influence in depth or quantify the flows (ecology) or values (economy) of the resources involved. Yet were they any less worthy of detailed attention than rents, wages or profits, over which so much ink (if still not enough) has been spilt? Yet it should also be clear by now that the vegetation of a region, whether a river was navigable in any way or not, and so forth, is the product of human action and choices. [ABSTRACT FROM AUTHOR]

We examine the patterns of expansion of exotic European earthworms in northeastern Europe and the western Great Lakes region of North America. These areas share many ecological, climatic and historical characteristics and are devoid of indigenous earthworm fauna due to Quaternary glaciations. These regions are being colonized by a similar suite of exotic lumbricid species and it is unlikely that this is the result of chance, but rather indicates that these species have particular characteristics making them successful invaders. The present macro-scale distributions of earthworm species in northern Russia show little connection to the pattern of the last glaciation. Rather, the primary factors that determine the current distributions of earthworm species include climatic conditions, the life history traits of different earthworm species, the suitability of habitat and intensity and patterns of human activity. In the western Great Lakes region of North America, there are three primary factors affecting current distributions of exotic earthworm species including the patterns of human activity and land use practices, the composition of particular source populations of earthworms associated with different vectors of transport and the soil and litter properties of habitats across the region. Disturbance of a habitat does not appear to be a prerequisite to the invasion and establishment of exotic earthworms. Analysis of the macro-scale distributions of Lumbricidae species in northeastern Europe may provide important insights into the potential of invasive European earthworm species to spread in North America, and identify potentially invasive species. [ABSTRACT FROM AUTHOR]

Recent studies document North American earthworm invasions and their profound effects on the structure of the soil profile, which is the habitat for soil microorganisms (mainly fungi and bacteria). Dramatic alterations made to these layers during earthworm invasion significantly change microbial community structure and therefore microbial activities such as C transformations. Understanding the impacts of earthworm invasion on the microbes themselves will give insight into earthworm effects on microbial activities. Bacterial and actinomycete communities in earthworm guts and casts have not been studied in environments recently invaded by earthworms. Earthworm invasion tended to decrease fungal species density and fungal species diversity and richness. The presence of earthworms decreased zygomycete species abundance probably due to disruption of fungal hyphae. Physical disruption of hyphae may also explain decreased mycorrhizal colonization rates, decreased mycorrhizal abundance and altered mycorrhizal morphology in the presence of earthworms. Mixing of organic layers into mineral soil during earthworm invasion tended to decrease microbial biomass in forest floor materials while increasing it in mineral soil. In newly invaded forest soils, microbial respiration and the metabolic quotient tended to decline. In forests where either the microbial community has had time to adapt to earthworm activities, or where the destruction of the forest floor is complete, as in invasions by the Asian Amynthas hawayanus, the presence of earthworms tends to increase the metabolic quotient indicating a shift to a smaller, more active microbial community. [ABSTRACT FROM AUTHOR]

The most conspicuous biological invasions in terrestrial ecosystems have been by exotic plants, insects and vertebrates. Invasions by exotic earthworms, although not as well studied, may be increasing with global commerce in agriculture, waste management and bioremediation. A number of cases has documented where invasive earthworms have caused significant changes in soil profiles, nutrient and organic matter dynamics, other soil organisms or plant communities. Most of these cases are in areas that have been disturbed (e.g., agricultural systems) or were previously devoid of earthworms (e.g., north of Pleistocene glacial margins). It is not clear that such effects are common in ecosystems inhabited by native earthworms, especially where soils are undisturbed. We explore the idea that indigenous earthworm fauna and/or characteristics of their native habitats may resist invasion by exotic earthworms and thereby reduce the impact of exotic species on soil processes. We review data and case studies from temperate and tropical regions to test this idea. Specifically, we address the following questions: Is disturbance a prerequisite to invasion by exotic earthworms? What are the mechanisms by which exotic earthworms may succeed or fail to invade habitats occupied by native earthworms? Potential mechanisms could include (1) intensity of propagule pressure (how frequently and at what densities have exotic species been introduced and has there been adequate time for proliferation?); (2) degree of habitat matching (once introduced, are exotic species faced with unsuitable habitat conditions, unavailable resources, or unsuited feeding strategies?); and (3) degree of biotic resistance (after introduction into an otherwise suitable habitat, are exotic species exposed to biological barriers such as predation or parasitism, ˵unfamiliar″ microflora, or competition by resident native species?). Once established, do exotic species coexist with native species, or are the natives eventually excluded? Do exotic species impact soil processes differently in the presence or absence of native species? We conclude that (1) exotic earthworms do invade ecosystems inhabited by indigenous earthworms, even in the absence of obvious disturbance; (2) competitive exclusion of native earthworms by exotic earthworms is not easily demonstrated and, in fact, co-existence of native and exotic species appears to be common, even if transient; and (3) resistance to exotic earthworm invasions, if it occurs, may be more a function of physical and chemical characteristics of a habitat than of biological interactions between native and exotic earthworms. [ABSTRACT FROM AUTHOR]