Environmental Change

This paper is aimed to elucidate the ecological scenario in Italy in the Early to Middle Pleistocene, when species of the genus Homo are known to spread across Europe in two distinct waves: earlier than 1.2 Ma and at about 600 ka, respectively. This topic represents both (1) a fundamental aspect for a better understanding of the factors that allowed humans to colonize the middle latitudes of Eurasia, and (2) a reasonable frontier for current Quaternary palaeobiology, thanks to increasing knowledge of regional and local patterns. As for Italy, a combination of palaeobotanical and palaeontological data sets shows on the one hand a general complexity in both space and time, and on the other hand changes of considerable importance within and among the biological communities. These changes had a major importance during the worldwide change in the Earth climatic system known as “Middle Pleistocene Revolution”, which according to our data culminates with crucial effects of the extreme conditions of MIS 16. Subsequently, during great part of the Middle Pleistocene, the peculiar features of the Italian territory may have favoured isolation and a local persistence of plant populations and possibly mammal taxa, humans included, as for instance suggested by the corrected chronology of the Ceprano calvarium.

... Urban channels, Erodibility, Allen et al. (2002). Urban channels, Spatial management in relation to hazards, Chin and Gregory (2005). Plunge pools, Act as energy dissipators to increase flow resistance and enhance channel stability, Allan and Estes (2005). Channelization. ...

1. Between the 1950s and 1990s the southern elephant seal Mirounga leonina underwent large decreases in population size throughout most of its breeding range in the Southern Ocean. While current population estimates suggest a recent recovery, some breeding populations have continued to decrease in recent years (Macquarie and Marion Islands), others have either remained stable (South Georgia, Kerguelen and Heard Island) or have increased (Peninsula Valdés, Argentina). 2. Intrinsic hypotheses for patterns of regional decline include factors that are affected by density-dependent mechanisms: (i) paucity of males, (ii) population 'overshoot' and (iii) pandemic disease. Extrinsic hypotheses include (iv) predation, (v) competition with fisheries concerns, (vi) interspecific competition, (vii) environmental change and (viii) human disturbance. Of the eight hypotheses proposed and examined here, we conclude that three can be discounted (i, v, viii), three are unlikely, but may require more testing (ii, iii, iv) and two are plausible (vi, vii). 3. The interspecific competition hypothesis is difficult to test because it requires the simultaneous monitoring of species that overlap directly with elephant seals, many of which have not been identified or little is known. However, an analysis of the relationship between log variance and log abundance (Taylor's power law) for populations of southern and northern elephant seals suggests that interspecific competition is not a significant factor in the decline of the southern elephant seal. 4. The hypothesis that decreases in southern elephant seal populations between the 1950s and 1990s were caused by the environmental change is the easiest to test and most plausible of the hypotheses. We propose a framework by which to test this hypothesis to determine how food availability affects individual survival.

The increased use of changeable characteristics in modern manufacturing and robotic systems and applications call for improved system control design that offers some degree of reconfigurability. The need for control reconfiguration of robotic systems arises due to ...

One of the important properties of a reliable communication network is the robustness to the environmental changes. This paper looks at the design of robust networks from a new perspective. A graph-theoretical metric, betweenness, in combination with network weight matrix is used to define a global quantity, network criticality, to characterize the robustness of a network. We show that network criticality is a monotone decreasing function of weight matrix. Furthermore, it is shown that network criticality is a strictly convex function of network weight matrix. This leads to a well-defined convex optimization problem to find the optimal weight matrix assignment to minimize network criticality.

In der gesamten Biosphäre üben schnelle und sich beschleunigende Veränderungen in der Landnutzung, des Klimas und der atmosphärischen Zusammensetzung, die vor allem durch anthropogene Kräfte angetrieben werden, gröXten Einfluss auf die Produktivität, die Biodiversität und die nachhaltige Bereitstellung von Ökosystemgutern und -leistungen aus. Bisher konzentrierten sich viele Untersuchungen, die ökologische Konsequenzen des globalen Wandels abschätzen, auf einzelne trophische Level. Das Verständnis dieser Veränderungen und die Vorhersage ihrer Konsequenzen kann jedoch davon profitieren, dass enträtselt wird, wie die Interaktionen zwischen den Primärproduzenten und den primären und sekundären Konsumenten (Pflanzen, Herbivore und Karnivore) beeinflusst werden. Naturschutz und -wiederherstellung kann verbessert werden, wenn die Arten und ihre Interaktionen auf angemessenen Skalen und unter Berücksichtigung, dass ober-und unterirdische Biota ökologisch miteinander verbunden sind, eingeschätzt werden. Der Selektionsdruck auf eine Art kann von anderen Arten abhängen, so dass der Verlust einer Art mehr für die Diversität bedeutet als nur den reinen Verlust eines Taxons. Er kann ebenso den Verlust anderer Arten des gleichen oder eines anderen trophischen Levels zur Folge haben sowie die Abschwächung oder sogar den Verlust von verschiedenen Selektionsdrücken. Wir geben einen Überblick über die Diskussionen zu trophischen Interaktionen in einer sich verändernden Welt in Bezug auf (i) die Skala der Ökosystemantwort auf Umweltveränderungen mit Betonung des Bodensubsystems, (ii) die Verbindung zwischen oberund unterirdischen Subsystemen und (iii) die natürliche Selektion und die Stabilität der Gemeinschaftsstruktur sowie der Ökosystemfunktion. Wir diskutieren die Notwendigkeit isolierte Subdisziplinen der Ökologie zusammen zu führen, um die Implikationen des globalen Wandels für Ökosystemprozesse zu verstehen.

In rare circumstances, scientists have been able to revive dormant propagules from ancestral populations and rear them with their descendants to make inferences about evolutionary responses to environmental change. Although this is a powerful approach to directly assess microevolution, it has previously depended entirely upon fortuitous conditions to preserve ancestral material. We propose a coordinated effort to collect, preserve, and archive genetic materials today for future studies of evolutionary change-a "resurrection paradigm." The availability of ancestral material that is systematically collected and intentionally stored using best practices will greatly expand our ability to illuminate microevolutionary patterns and processes and to predict ongoing responses of species to global change. In the workshop "Project Baseline," evolutionary biologists and seed storage experts met to discuss establishing a coordinated effort to implement the resurrection paradigm.

The knowledge of past climatic and environmental conditions in central Mexico, interpreted extensively from lacustrine records, is restricted to the last ca. 50,000 years. The recent discovery of new localities of paleosol sequences in central Mexico and the reconnaissance of their usefulness as records of environmental change provides a new source of information about past climatic conditions for times prior to the last full glacial. In this paper, we analyze the mineral magnetic properties of a sequence of paleosols developed in volcaniclastic deposits and evaluate these data as paleoenvironmental proxy. The sequence consists of a modern Phaeozem soil and seven late Quaternary Luvisol paleosols outcropping in Barranca Tlalpan, Tlaxcala, Mexico. Rock magnetic analysis was used to study the concentration and type of magnetic mineralogy. The mineral magnetic data, supported by soil morphological and chemical data, are interpreted to indicate that the paleosols can be grouped in three sets, each with distinct characteristics. The Red set paleosols P7 and P6 are the most weathered, and present the highest magnetic concentration composed of Ti-magnetite and ultrafine magnetite (<30 nm). The Brown set of paleosols P5, P4 and P3, with few redoximorphic features, have coarser grains and lower concentrations of magnetic minerals. The Gray set, paleosols P2 and P1, have abundant redoximorphic features including Fe-Mn nodules, and have a multicomponent magnetic mineralogy of coarse size. Paleosols from the Red and Brown sets conserve evidence of neoformation of ultrafine magnetite grains in the Bt horizons, probably derived from pedogenic processes. However, direct observations by microscopy and rock magnetism parameters point to a later destruction of this ultrafine fraction. We consider that even if pedogenic processes resulted in the formation of ultrafine magnetite, redoximorphic conditions under humid climates are responsible of the destruction of magnetic minerals. Such conditions may have strongly prevailed in the Gray set paleosols, whereas the Red set was probably developed under contrasting seasonal precipitation climates, which favored the formation and preservation of pedogenic magnetic minerals.

One of the great academic challenges for management instructors is developing interesting and educational forums to help students learn and integrate abstract concepts. This article describes an original class exercise developed to facilitate this integrative process and improve students' understanding of complex material from micro-and macro-organizational theory. Developed from Kreitner's (1995) review of the four major environmental change drivers, this exercise incorporates a power perspective similar to Dubin's (1958) to encourage student understanding of how power in organizations is gained and lost as the social, economic, political/legal, and technological environment changes. In addition, this exercise engages students in a valuable group activity to further develop interpersonal and group dynamic skills. Students understand power differentials by examining the series of exchanges between constituents in terms of how important or essential the exchanges are and how replaceable or exclusive they are (Dubin, 1958).

A 5000-yr stratigraphic record containing fossil pollen, charcoal, and bones of the extinct Quaternary megafauna from Andolonomby, a hypersaline pond in arid southwestern Madagascar, shows evidence for climatic desiccation beginning about 3000 yr B.P. Pollen spectra shift at this time from primarily arboreal taxa characteristic of forests and woodlands of more mesic western Madagascar, to wooded savanna typical of somewhat drier localities. Between 3000 and 2000 yr B.P., the site became increasingly arid. Charcoal and pollen evidence indicates that increased fire and disturbance occurred at the site beginning ca. 1900 yr B.P., probably signaling the beginning of human settlement in the area. The fossil record suggests that various human and natural factors on the island may have interacted in the subsequent millennium to culminate in the extinction of the entire endemic megafauna.

Land-use change models are important tools for integrated environmental management. Through scenario analysis they can help to identify near-future critical locations in the face of environmental change. A dynamic, spatially explicit, land-use change model is presented for the regional scale: CLUE-S. The model is specifically developed for the analysis of land use in small regions (e.g., a watershed or province) at a fine spatial resolution. The model structure is based on systems theory to allow the integrated analysis of land-use change in relation to socio-economic and biophysical driving factors. The model explicitly addresses the hierarchical organization of land use systems, spatial connectivity between locations and stability. Stability is incorporated by a set of variables that define the relative elasticity of the actual land-use type to conversion. The user can specify these settings based on expert knowledge or survey data. Two applications of the model in the Philippines and Malaysia are used to illustrate the functioning of the model and its validation.

Mobile livestock herders have long been seen as the main culprits of over-stocking and rangeland degradation. In recent years, however, anthropolo-gists and ecologists have argued that African pastoralists have developed sustainable modes of pasture management based on a ...

To anticipate daily environmental changes, most organisms developed endogenous timing systems, the so-called circadian (B24 hours) clocks. Circadian clocks exist in most peripheral tissues and govern a huge variety of cellular, metabolic, and physiological processes. Recent studies have suggested daytime-dependent variations in epidermal functions such as barrier recovery and pH homeostasis. However, a local circadian clock in epidermal keratinocytes has not been reported yet, and as such the molecular link between the circadian system and epidermal physiology remains elusive. In this study we describe a functional cell autonomous circadian clock in human adult low calcium temperature (HaCaT) keratinocytes. Using live-cell bioluminescence imaging and mRNA expression time series, we show robust circadian transcription of canonical clock genes in synchronized HaCaT keratinocytes. Genetic and pharmacological perturbation experiments as well as the phase relations between clock gene rhythms confirm that the molecular makeup of the HaCaT keratinocyte clock is very similar to that of other peripheral clocks. Furthermore, temperature was identified to be a potent time cue (Zeitgeber) for the epidermal oscillator. Temperature cycles entrain HaCaT keratinocytes, leading to the identification of rhythmic expression of several genes involved in epidermal physiology such as cholesterol homeostasis and differentiation. Thus, we present HaCaT keratinocytes as an excellent model to study the regulation of keratinocyte physiology by the circadian clock in a simple yet robust in vitro system.

The influence of temperature, light, salinity and nutrient availability on the release of volatile halogenated hydrocarbons was investigated in the Antarctic red macroalgal species Gymnogongrus antarcticus Skottsberg. Compared to standard culture condition, an increase in the release rates of iodocompounds was generally found for the exposure of the alga to altered environmental conditions. Macroalgae exhibited higher release rates after adaptation for two months to the changed factors, than after short-term exposure. Monitoring the release rates during a 24 h incubation period (8.25 h light, 15.75 h darkness) showed that changes between light and dark periods had no influence on the release of volatile halocarbons. Compounds like bromoform and 1-iodobutane exhibited constant release rates during the 24 h period. The formation mechanisms and biological role of volatile organohalogens are discussed. Although marine macroalgae are not considered to be the major source of biogenically-...

A 9000-year carbonate-rich sediment sequence from a small hard-water lake in northernmost Sweden was studied by means of multi-component stable carbon isotope analysis. Radiocarbon dating of different sediment fractions provides chronologic control and reveals a rather constant hard-water effect through time, suggesting that the lake has remained hydrologically open throughout the Holocene. Successive depletion of 13 C in fine-grained calcite and carbonate shells during the early Holocene correlate with a change in catchment vegetation from pioneer herb communities to boreal forest. The vegetational change and associated soil development likely gave rise to an increased supply of 13 C-depleted carbon dioxide in groundwater recharging the lake. This process is therefore believed to be the main cause of decreasing values of 13 C in dissolved inorganic carbon of the lake and thereby in limnic carbonates. Strongly 13 C-depleted sedimentary organic matter may be related to enhanced kinetic fractionation during photosynthetic assimilation by means of proton pumping in Characean algae. This interpretation is supported by a substantial offset between 13 C of DIC as recorded by mollusc shells and 13 C of fine-grained calcite.

With improved observation methods, increased winter navigation, and increased awareness of the climate and environmental changes, research on the Baltic Sea ice conditions has become increasingly active. Sea ice has been recognized as a sensitive indicator for changes in climate. Although the interannual variability in the ice conditions is large, a change towards milder ice winters has been detected from the time series of the maximum annual extent of sea ice and the length of the ice season. On the basis of the ice extent, the shift towards a warmer climate took place in the latter half of the 19th century. On the other hand, data on the ice thickness, which are mostly limited to the land-fast ice zone, basically do not show clear trends during the 20th century, except that during the last 20 years the thickness of land-fast ice has decreased. Due to difficulties in measuring the pack-ice thickness, the total mass of sea ice in the Baltic Sea is, however, still poorly known. The ice extent and length of the ice season depend on the indices of the Arctic Oscillation and North Atlantic Oscillation. Sea ice dynamics, thermodynamics, structure, and properties strongly interact with each other, as well as with the atmosphere and the sea. The surface conditions over the ice-covered Baltic Sea show high spatial variability, which cannot be described by two surface types (such as ice and open water) only. The variability is strongly reflected to the radiative and turbulent surface fluxes. The Baltic Sea has served as a testbed for several developments in the theory of sea ice dynamics. Experiences with advanced models have increased our understanding on sea ice dynamics, which depends on the ice thickness distribution, and in turn redistributes the ice thickness. During the latest decade, advance has been made in studies on sea ice structure, surface albedo, penetration of solar radiation, sub-surface melting, and formation of superimposed ice and snow ice. A high vertical resolution has been found as a prerequisite to successfully model thermodynamic processes during the spring melt period. A few observations have demonstrated how the river discharge and ice melt affect the stratification of the oceanic boundary layer below the ice and the oceanic heat flux to the ice bottom. In general, process studies on ice-ocean interaction have been rare. In the future, increasingly multidisciplinary studies are needed with close links between sea ice physics, geochemistry and biology.

Over the past two decades, archaeologists and physical anthropologists investigating the prehistoric Anasazi culture have identified numerous cases of suspected cannibalism. Many scholars have suggested that starvation caused by environmental degradation induced people to eat one another, but the growing number of cases as well as their temporal and spatial distribution challenge this conclusion. At the same time, some scholars have questioned the validity of the osteoarchaeological indicators that are used to identify cannibalism in collections of mutilated human remains. To address these concerns, this study attempts to reconstruct the behaviors that produced the Anasazi skeletal trauma by first examining ethnographic, ethnohistoric, and archaeological material for analogues useful for interpreting mutilated human remains and then correlating these analogues with the evidence from the Southwest. The patterns suggest that different behaviors are responsible for the Anasazi skeletal mutilation seen in different time periods. To explain these differences, the study employs game theoretical models that examine how changing social and physical contexts altered the sociopolitical strategies that Anasazi groups would likely have employed. The results suggest that violent mutilation and perhaps cannibalism was an intentional sociopolitical strategy of intimidation used during Pueblo II (A.D. 900–1100), while environmental changes after this period promoted resource-based warfare and the incidental skeletal trauma associated with this behavior.

With the continuous development, in the last decades, of analytical techniques providing complex information at single cell level, the study of cell heterogeneity has been the focus of several research projects within analytical biotechnology. Nonetheless, the complex interplay between environmental changes and cellular responses is yet not fully understood, and the integration of this new knowledge into the strategies for design, operation and control of bioprocesses is far from being an established reality. Indeed, the impact of cell heterogeneity on productivity of large scale cultivations is acknowledged but seldom accounted for. In order to include population heterogeneity mechanisms in the development of novel bioprocess control strategies, a reliable mathematical description of such phenomena has to be developed. With this review, we search to summarize the potential of currently available methods for monitoring cell population heterogeneity as well as model frameworks suitable for describing dynamic heterogeneous cell populations. We will furthermore underline the highly important coordination between experimental and modeling efforts necessary to attain a reliable quantitative description of cell heterogeneity, which is a necessity if such models are to contribute to the development of improved control of bioprocesses.

In the past mobile robot research was often focused to various kinds of point-to-point transportation tasks. Service tasks, such as floor cleaning, require specific approaches for path planning and vehicle guidance in real indoor environments. This article discusses automatic planning of a feasible cleaning path considering a 2D-map as well as kinematic and geometric robot models. Path construction makes use of two typical motion patterns. Each pattern is defined by a sequence of subgoals indicating robot position and orientation. Results of automatic path planning are illustrated by realistic examples of typical robots and cleaning environments. Vehicle guidance includes initialization of robot location, path execution, accurate path tracking and detection of unexpected environmental changes. Path tracking is achieved by subgoal modification during cleaning motion using data from the dead-reckoning and landmark localization systems. If obstacles permanently block the preplanned path, an automatic map update and path replanning is performed. Experimental results with the mobile robot MACROBE confirm the feasibility of the developed planning and guidance system.

The aim of this study was to evaluate how the summer and winter conditions affect the photosynthesis and water relations of well-watered orange trees, considering the diurnal changes in leaf gas exchange, chlorophyll (Chl) fluorescence, and leaf water potential (Ψ) of potted-plants growing in a subtropical climate. The diurnal pattern of photosynthesis in young citrus trees was not significantly affected by the environmental changes when compared the summer and winter seasons. However, citrus plants showed higher photosynthetic performance in summer, when plants fixed 2.9 times more CO 2 during the diurnal period than in the winter season. Curiously, the winter conditions were more favorable to photosynthesis of citrus plants, when considering the air temperature (< 29 ºC), leaf-to-air vapor pressure difference (< 2.4 kPa) and photon flux density (maximum values near light saturation) during the diurnal period. Therefore, low night temperature was the main environmental element changing the photosynthetic performance and water relations of well-watered plants during winter. Lower whole-plant hydraulic conductance, lower shoot hydration and lower stomatal conductance were noticed during winter when compared to the summer season. In winter, higher ratio between the apparent electron transport rate and leaf CO 2 assimilation was verified in afternoon, indicating reduction in electron use efficiency by photosynthesis. The high radiation loading in the summer season did not impair the citrus photochemistry, being photoprotective mechanisms active. Such mechanisms were related to increases in the heat dissipation of excessive light energy at the PSII level and to other metabolic processes consuming electrons, which impede the citrus photoinhibition under high light conditions.

In some continental and island sites in the western Mediterranean basin, the Holocene vegetation and climate dynamics seem to show the same patterns in time and space. Nevertheless, different synchronous scenarios have been proposed from other south European, North African and Near Eastern pollen records from around the Mediterranean basin. Striking similarities and synchronisms have been found between Sicily and the Balearic Islands. These islands, although under different bioclimatic influences, show similarities in the main trends of vegetation and climate dynamics during the Post-glacial. Lago di Pergusa is the only natural inland lake in Sicily and because of its geographical location, has a good potential sensitivity to the climatic changes of the Mediterranean basin. Likewise, coastal sediments from Minorca and Majorca, the Balearic Islands, have similar peculiarities. The present-day environmental situation, now that most of the natural vegetation in these islands has disappeared, has been brought about either by a climatic trend towards increasing aridity or an increase in human activities. It seems clear that prehistoric human people alone could not have caused all the environmental changes recorded in the last millennia in both places.

When children in foster care are reunified with their families of origin they encounter changes that may influence their well-being in both positive and negative ways. We examined the effects of reunification among 218 children in foster care to test an integrative model of the effects of reunification using structural equation modeling. We hypothesized that reunification would exert indirect effects on subsequent child adjustment via changes in adverse life events, perceived social isolation, and mental health service utilization. Results indicated no direct effect of reunification on subsequent internalizing problems, but reunification was related to increased adverse life events that, in turn, were related to elevated symptoms. Second, reunification was negatively associated with mental health service use. Finally, reunification was associated with decreased child perceptions of social isolation. In summary, reunification with biological parents is associated with multiple environmental changes, with most but not all effects indicating negative consequences.

The progression of implementation of an information systems strategy in a UK acute hospital is described. The case study describes the IS strategy, the conditions that led to its development and its content. It then follows the progression of attempts to implement the strategy over five years. At the end of five years, little of the strategy has been implemented. Reasons for this are discussed structured around the following questions: Why was the IS strategy produced? What external environmental changes influenced implementation?, How did internal organisational change affect implementation? In what ways was the IT strategy naïve? Was the IS strategy exercise at the hospital of any value? Lessons for both researchers and practitioners are presented. It is concluded that, far from being a irrelevant exercise, the development of the IS strategy at the hospital provided a catalyst for organisational learning and culture change which enabled the hospital to avoid some IT investment mis...

Thermophilic anaerobic digestion offers an attractive alternative for the treatment of medium-and high-strength wastewaters. However, literature reports reveal that thermophilic wastewater treatment systems are often more sensitive to environmental changes than the well-defined high-rate reactors at the mesophilic temperature range. Also, in many cases a poorer effluent quality is experienced while the carry over of suspended solids in the effluent is relatively high. In this paper recent achievements are discussed regarding the process stability of thermophilic anaerobic wastewater treatment systems. Laboratory experiments reveal a relatively low sensitivity to temperature changes if high-rate reactors with immobilized biomass are used. Other results show that if a staged process is applied, thermophilic reactors can be operated for prolonged periods of time under extreme loading conditions (80-100 kg chemical oxygen demand.m-3.day-1),,while the concentrations of volatile fatty acids in the effluent remain at a low level.

The term 'Sustainable Development' is brandished by modern businesses as a marketing ploy used to suggest evidence of ethical conduct, innovative thinking and moral superiority. However, when analysing an organisations' adoption of sustainable practices, it is often clear-within the UK-that there are few activities that have been undertaken as an ethical stance instead of legal obligation (McCormick in Environmental politics and policy in industrialized countries, MIT, London, 2002). Our hypothesis is that most methodologies and practices for environmental management do not adopt a holistic perspective, causing significant problems in implementation from inadequate structures and communication channels (Espinosa et al. in Eur J Oper Res, 187:636-651, 2008). In particular we consider that most organisations are currently stifled with management hierarchies that prevent informal/social networking, which may be one of the most powerful natural forms for self-organisation. It is proposed that sustainable development requires more efficient communication channels that foster self-organisation and selfregulation as a method for more productive change processes. In this paper, we explain the reasons why meta-systemic principles of self-organisation and distributed network management offer clear criteria to design an environmental management system that operates on the basis of self-controlled individuals and communities.

Global climate change, linked to astronomical forcing factors, has been implicated in faunal evolutionary change in equatorial Africa, including
the origin and diversification of hominin lineages. Empirical terrestrial data demonstrating that orbital forcing has a significant effect,
or is detectable, at early hominin sites in equatorial continental interiors during the Pliocene, however, remain limited. Sedimentation patterns in
the Baringo Basin within the Central Kenyan Rift Valley between ca. 2.7 and 2.55 Ma, controlled by climatic factors, provide a detailed paleoenvironmental
record spanning 35 fossil vertebrate localities, including three hominin sites. The succession includes a sequence of diatomites
that record rhythmic cycling of major freshwater lake systems consistent with w23-kyr Milankovitch precessional periodicity. The temporal
framework of shifting precipitation patterns, relative to Pliocene insolation curves, implicate African monsoonal climatic control and indicate
that climatic fluctuations in Rift Valley ecosystems were paced by global climatic change documented in marine cores. These data provide direct
evidence of orbitally mediated environmental change at Pliocene Rift Valley hominin fossil localities, providing a unique opportunity to assess
the evolutionary effect of short-term climatic flux on late Pliocene East African terrestrial communities.

Contributing to and providing links between environmental variability and adaptive livelihood strategies, household well-being and development policy, this paper presents an analysis that explores theoretical and policy debates on whether livelihood adaptations and emerging strategies within the context of current environmental change have received the required policy attention and intervention. Livelihood diversification as a poverty reduction strategy has been argued to result in improved well-being or perpetuates a cycle of impoverishment. The paper focuses on communities in vulnerable environments with limited well-being and poor assets. The study examines the changing livelihood strategies and livelihood options of households located within ecosystems perceived to be experiencing environmental change in Northeastern Ghana. On-farm and non-farm diversification and migration as livelihood strategies considered as survival strategies in environments experiencing rising temperatures and erratic rainfall patterns. It is argued that diversified livelihoods are operated within a cycle of impoverishment. The paper calls for geographically and locally sensitive policy intervention approaches that can sustainably expand the livelihood options of the poor in changing environments.

In this paper we present 2 years of data obtained during the late summer period (September 2003 and September 2004) for the East Siberian Arctic shelf (ESAS). According to our data, the surface layer of shelf water was supersaturated up to 2500% relative to the present average atmospheric methane content of 1.85 ppm, pointing to the rivers as a strong source of dissolved methane which comes from watersheds which are underlain with permafrost. Anomalously high concentrations (up to 154 nM or 4400% supersaturation) of dissolved methane in the bottom layer of shelf water at a few sites suggest that the bottom layer is somehow affected by near-bottom sources. The net flux of methane from this area of the East Siberian Arctic shelf can reach up to 13.7 × 10 4 g CH 4 km − 2 from plume areas during the period of ice free water, and thus is in the upper range of the estimated global marine methane release. Ongoing environmental change might affect the methane marine cycle since significant changes in the thermal regime of bottom sediments within a few sites were registered. Correlation between calculated methane storage within the water column and both integrated salinity values (r = 0.61) and integrated values of dissolved inorganic carbon (DIC) (r = 0.62) suggest that higher concentrations of dissolved methane were mostly derived from the marine environment, likely due to in-situ production or release from decaying submarine gas hydrates deposits. The calculated late summer potential methane emissions tend to vary from year to year, reflecting most likely the effect of changing hydrological and meteorological conditions (temperature, wind) on the ESAS rather than riverine export of dissolved methane. We point out additional sources of methane in this region such as submarine taliks, ice complex retreat, submarine permafrost itself and decaying gas hydrates deposits.

Hurricanes are the costliest natural disasters in the United States. Understanding both hurricane frequencies and intensities is a topic of great interest to meteorologists, decision makers and the general public alike. Previous research has suggested that damage has been dramatically increasing within the last two decades, in part due to rapid increase of population and wealth in coastal regions (Blake et al., 2005; Emanuel, 2005;

Several long-term mark recapture studies have been conducted on box turtles (Terrapene c. carolina) providing valuable information on life span, basic demography, home range, and apparent effects of environmental changes on box turtle survival. One of the longest studied populations was first marked in 1942 on the Patuxent Wildlife Research Center in Maryland, and has been surveyed every 10 years