Composition and Host-Use Patterns of a Scarab Beetle (Coleoptera: Scarabaeidae) Community Inhabiting the Canopy of a Lowland Tropical Rainforest in Southern Venezuela

The adult scarab beetle fauna of the canopy in a lowland tropical rainforest in southern Venezuela was observed and collected by means of a 42 m-tall tower crane for a complete year. This first census of an entire Amazonian canopy scarab community was embedded within the interdisciplinary research project Towards an understanding of the structure and function of a Neotropical rainforest ecosystem with special reference to its canopy organized by the Austrian Academy of Science. The Scarabaeidae represented one of the most species-rich beetle families in the canopy of the crane plot and were therefore selected for a detailed analysis of host-use patterns. Thirty-three species of Scarabaeidae with 399 individuals were recorded, including two species represented by singletons. Subfamilies abundant in the canopy were the Rutelinae, Dynastinae, and Melolonthinae. Species were diurnal or nocturnal flower visitors restricted in their occurrence to their host trees during the flowering season. The scarab beetles remained commonly on one host tree species throughout the entire flowering period and switched to another host tree species only after depletion of food resources. Some species fed on extrafloral nectar but feeding on fruits and leaves was uncommon in the observed species. Most species showed a broad host range, often with abundant species recorded on several host trees. Seven species were found exclusively on one tree species. The co-occurrence of up to five congeneric species sharing the same host trees and diet was conspicuous. With this study, it could be shown how species of Scarabaeidae track available food resources within the canopy of a tropical rainforest

Erkenntnisse aus der Individualmarkierung im Wanderfalken-Baumbrüterprojekt

Das Wanderfalken-Baumbrüterprojekt wurde 1990 in Brandenburg begonnen, ab 1995 vom Landesjagdverband auch in Mecklenburg-Vorpommern und ab 2001 in Sachsen-Anhalt durchgeführt. Ziel ist es, den ehemals von Baumbrütern des Wanderfalken besiedelten Raum von der Weser bis Zentralrussland durch Auswilderung von auf Baumbrut geprägten Vögeln wieder für diese Art zu erschließen. Eine spontane Wiederbesiedlung durch Wanderfalken aus Fels- und Gebäudebruten ist aufgrund der Sonderstellung der Baumbrut bei dieser Art nicht zu erwarten

An Agro-Sylvo-Pastoral Approach to Desertification Control and Increased Productivity of the Sahel

The southern arid fringe of the Sahara Desert, called the Sahel, is progressively becoming less productive through a systematic deterioration of the environment. Population increases and technological advances have encouraged ecological degradation through man\u27s normal activities for survival. The degradation process has been referred to as desertification, desertization, desert encroachment, and desert creep

Effects of Clearcutting on Forage Production, Quality and Decomposition in the Caatinga Woodland of Northeast Brazil: Implications to Goat and Sheep Nutrition

Clearing of trees from the so-called caatinga woodland that characterizes the vegetation of the semi-arid region of northeast Brazil offers possibilities for increasing forage production. This research analyzed the first-year effects of clearing caatinga on dry season forage for goats and sheep. In addition, factors affecting litter decomposition on cleared and uncleared caatinga were assessed to evaluate the viability of deferring grazing of forages during the wet season for use later in the dry season. Removing the trees resulted in a sixfold increase in production of herbaceous vegetation, however, 88 percent of the increased yield on the cleared areas was in the form of stems from herbaceous vegetation. Seventy-two percent of the stems were unpalatable to goats and sheep because of the massive size of those stems. Leaf litter from trees was an important component of the diets of goats and sheep during the dry season and clearing reduced production of this forage threefold. Clearing resulted in increased decomposition of leaf litter. Changes in microclimate played only a minor role in this difference. The reduction in the amount of leaf litter from trees relative to litter from herbs had the greatest effect on decomposition rates of dry season forage because tree litter decomposed less rapidly than did herbaceous litter. The slow decomposition of leaf litter during the dry season suggests that deferment. of cleared or uncleared caatinga for use as forage in the latter part of the dry season is feasible. An analysis of the diets of esophageally fistulated goats and sheep indicated that clearing may be a viable alternative for improving the amount and the in vitro dry matter digestibility of the forage consumed during the dry season the first-year post-treatment. These increases were attributed to an absolute greater abundance of preferred herbaceous forages (i.e., foliage and leaf litter) and to the persistent green foliage on coppicing woody plants. Dietary nitrogen appeared to limit intake, and clearing did not improve availability of this nutrient to sheep and goats at the higher levels of grazing pressure applied in this study. Other ecosystem considerations such as watershed protection and long-term community stability must also be considered in decisions to remove the tree canopy of the caatinga

Haematoprotozoan parasites of marine fishes with special reference to mariculture

This research study is divided into 4 major sections. Section A deals with the world-wide distribution of the haematoprotozoan parasites of marine fishes. These are tentatively divided into 3 major groups: the Haemogregarines, the Trypanosomes and the Trypanoplasms and one group of ill defined and controversal organisms including Haemohormidium sp. and Dactylosoma sp. The results of extensive surveys of the coastal waters of France, Scotland and Wales with added examples from the Mediterranean Sea substantiate the zoogeographical distribution of these parasites. Two species of haematoprotozoan parasites Haemogregarina simondi and Trypanosoma soleae are re-described, earlier accounts dating from the beginning of the century being considered incomplete. A new species of haemogregarine is described from the farmed turbot (Scophthalmus maximus) as Haemogregarina sachai n. sp. and an unidentified species of Haemohormidium found occasionally in turbot and Dover sole (Solea soles) is also described. In addition Haemogregarina sp. were encountered in certain wild marine fish from the Atlantic coast of France e. g. Zeus faber, Sebastes sp., Trisopterus luscus, Pagellus bogaraveo and Raja sp. and from the coastal waters of Malta e. g. Peristedion cataphractum and Oblade melanura. However, they were not found in sufficient numbers to allow a definite description. The value of surveys of wild fish populations is discussed in the light of zoogeographical distribution, the apparent periodicity of these parasites and a seasonal variation of parasitism. Section B attempts to summarize the knowledge of the mode of transmission of marine haematoprotozoan parasites by piscicolid leeches as intermediate hosts and vectors. The developmental stages of a trypanosome, probably Trypanosoma murmanensis from the Atlantic cod Gadus morhua are described in the marine leech Calliobdella nodulifera. Stages of a haemogregaririe were observed in the same leech. The development of the turbot haemogregarine Haemogregarina sachai n. sp. in artificially infected leeches is also described up to the 20th day post infection. Transmission of this haemogregarine to apparently uninfected turbot via this leech was not successful. Various stages of development of Haemogregarina simondi are described in its apparently natural vector, the marine leech Hemibdella soleae, and transmission with infected leeches to apparently healthy hatchery reared soles was achieved. Thus it was shown for the first time that marine leeches can serve also as vectors for haemogregarines. Stages of this haemogregarine are also described in the blood-sucking ectoparasitic copepod Lernaeocera sp. parasitizing the haemogregarine infected soles. These results are discussed in relation to the feeding behaviour and migration patterns of the fish hosts, the periodicity of the parasites and possible other vectors or other ways of acquiring an infection with these haematoprotozoan parasites. In Section C the pathogenicity of the haematoprotozoan parasites of marine fishes is summarized from previous accounts among wild fish populations and compared with the situation in aquaculture. The pathogenicity of the two haemogregarines, Haemogregarina simondi and Haemogregarina sachai n. sp., accidentally introduced into several fish farming establishments connected with the effluent cooling waters of a nuclear power station is described with special reference to the possible source of the infection. The results of therapy trials and control programs are discussed in the light of the periodic reappearance of the parasites, the possibility of carrier fish existing, the immune status of the host and the possible role of an intermediate host or vector in maintaining the infection. Possible means of controlling the pathogenicity of marine haemogregarines and perhaps other haematoprotozoan parasites when they occur in farmed marine fishes are also discussed. In Section D are described for the first time, the ultrastructural characteristics of various stages of the haematoprotozoan parasites of marine fishes in fish hosts and vectors. The electronmicroscopical studies are limited to Haemogregarina sachai n. sp. and Haemogregarina simondi, for which the ultrastructure of schizonts from the spleen and blood, intracellular merozoites and free gametocytes were contrasted. In addition stages of H. simondi were demonstrated in Hemibdella soleae and Lernaeocera sp. The fine structure of the various organelles encountered was compared with that of related organisms from other cold-and warm-blooded vertebrates. In conclusion attention is drawn to the need for more investigations in this field of host-parasite relationship of marine haematoprotozoan parasites and their vectors and their pathogenic-action as seen in a confined and artificial environment such as the marine aquaculture

Waste-heat recovery and power generation with reciprocating motion

The utilization of renewable and waste heat from industrial processes is an important step towards the reduction of emissions and the increase in the efficiency of energy systems. This heat is available at different and mostly low grade temperatures (ca 100 °C to 550 °C) and various mass flow rates. The current work focuses on the understanding of the most important parameters that determine the potential efficiency of generalised heat engines from a technology agnostic perspective, followed by the development of modelling frameworks that correspond to two specific engines that can make use of heat sources at low temperature levels. The efficiency and power output of generalised heat engines when optimising different objective functions have been examined. These are the power output and the ecological- criterion value. The efficiency remains within upper and lower bounds, when varying the heat capacity of the heat source and heat sink, as well as the contact time between the external heat reservoirs and the working fluid. The corresponding power output variations are considerably higher than those observed for the efficiency. The power output reaches a maximum for values of the heat capacity of the heat source or sink larger than those of the working fluid or for contact times of the heat-exchange processes that are short or of approximately equal length. From these technology-agnostic considerations and the resulting limits that are imposed on the expected performance of real engines, we proceed to consider two specific technologies in the context of waste-heat recovery and power generation. The common feature of these technologies is that they involve reciprocating motion, either as part of a dedicated component (i.e., expander) or inherently as part of the overall operation of the entire device. The first engine, called Up-THERM, is a two-phase thermofluidic oscillator with low investment costs. A dynamic non-linear model framework of the Up-THERM has been developed. The dominant fluid or thermal effect in each engine component is described by a first-order differential equation. The temperature profile along the heat-exchanger walls has been validated experimentally. After the validation a parametric study has been performed examining the effects of five geometric parameters and the heat-source temperature on the engine’s performance. It is found that the heat-source temperature should be high for high power outputs, the volume of the gas spring small and the diameterof the displacer cylinder should be at its nominal value or somewhat larger. The Up- THERM engine has been compared with organic Rankine cycle (ORC) engines in terms of technical and economical performance. While for low temperature heat-sources the ORC engines have a higher power output, for higher heat-source temperatures this becomes comparable between the two engines. Due to the lower investment costs, the costs per unit power become lower for the Up-THERM engine at high heat-source temperatures. The second engine is an open cycle hot air Ericsson engine. It uses two reciprocating- piston cylinders as compressor and expander, inter-linked by a heat exchanger. It is particularly suitable for heat-sources at higher temperatures with small mass flow rates. The engine is described by a system of 12 equations. Pressure losses across valves, heat losses in the cylinders, friction and mass leakage are considered as loss mechanisms. Pres- sure losses and heat losses together account for 99% of the total losses. An optimisation using neural networks has been performed at five different heat-source conditions. Three operational and four geometric parameters are varied to maximise the power output of the engine. The net power output scales nearly linearly with the mass flow rate of the heat source. The thermal efficiency is constant at around 15% for a heat-source tem- perature of 350 °C and mass flow rates between 0.025 kg/s and 0.1 kg/s. The exergy efficiency increases with decreasing mass flow rate from 3.1% to 6.4%. For a heat-source mass flow rate of 0.1 kg/s the net power output increases from 1.9 kW at 250 °C to 7.2 kW at 350 °C and 48 kW at 450 °C. Higher heat-source temperatures also result in higher thermal efficiencies, but lower exergy efficiencies. Comparing the Ericsson to an equivalent ORC engine, which is a mature waste-heat recovery technology, reveals that the former can operate at lower thermal heat inputs, which allows operation over a wider range of applications with different heat-source mass flow rates. For comparable heat inputs and heat-source temperatures the power output and thermal efficiency of the Ericsson engine are higher than those of the ORC engine. Therefore, the Ericsson engine is an attractive alternative to existing waste-heat recovery technologies.Open Acces