Global phylogeography of<Emphasis Type="Italic"> Cassiopea</Emphasis> (Scyphozoa: Rhizostomeae): molecular evidence for cryptic species and multiple invasions of the Hawaiian Islands

The upside-down jellyfish Cassiopea is a globally distributed, semi-sessile, planktonically dispersed scyphomedusa. Cassiopea occurs in shallow, tropical inshore marine waters on sandy mudflats and is generally associated with mangrove-dominated habitats. Controversy over the taxonomy of upside-down jellyfishes precedes their introduction to the Hawaiian Islands during the Second World War, and persists today. Here we address the global phylogeography and molecular systematics of the three currently recognized species: Cassiopea andromeda, C. frondosa, and C. xamachana. Mitochondrial cytochrome c oxidase I (COI) sequences from Australia, Bermuda, Fiji, the Florida Keys, the Hawaiian Islands, Indonesia, Palau, Panama, Papua New Guinea, and the Red Sea were analyzed. Highly divergent COI haplotypes within the putative species C. andromeda (23.4% Kimura 2-parameter molecular divergence), and shared haplotypes among populations of two separate putative species, C. andromeda and C. xamachana from different ocean basins, suggest multiple anthropogenic introductions and systematic confusion. Two deeply divergent Oahu haplotypes (20.3%) from morphologically similar, geographically separate invasive populations indicate long-term (14–40 million years ago) reproductive isolation of phylogenetically distinct source populations and cryptic species. Data support at least two independent introductions to the Hawaiian Islands, one from the Indo-Pacific, another from the western Atlantic/Red Sea. Molecular phylogenetic results support six species: (1) C. frondosa, western Atlantic (2) C. andromeda, Red Sea/western Atlantic/Hawaiian Islands (3) C. ornata, Indonesia/Palau/Fiji (4) Cassiopea sp. 1, eastern Australia (5) Cassiopea sp. 2, Papua New Guinea and (6) Cassiopea sp. 3, Papua New Guinea/Hawaiian Islands.Communicated by P.W. Sammarco, Chauvin     

Social rank, fecundity and lifetime reproductive success in wild European rabbits (Oryctolagus cuniculus)

Wild European rabbits of both sexes have separate linear rank orders, which are established and maintained by intensive fights. This paper presents data from a 14-year study (1987-2000) on the population physiology and behavioural ecology of wild rabbits living in a 22,000 m² enclosure and focuses on the relationship between social rank and reproduction in females. Group composition, social ranks, fecundity and reproductive success were known for all females (n=197) from the outset of their first reproductive season at an age of about 300 days until their death. The annual reproductive success of females was influenced to a large extent by their social rank. This depended on two effects of about equal strength: a higher fecundity of high-ranking females and a lower mortality of their offspring between birth and adulthood. The lifetime reproductive success of the females varied greatly. Only about 50% of all females had any reproductive success (range: on to nine adult offspring). The social rank achieved by the females during their first reproductive season substantially influenced their lifetime reproductive success: The mean reproductive lifespan and lifetime fitness of high-ranking females (ranks 1 and 2) was about 60% greater than that of lower-ranking females, although many of the latter also gained dominant positions in subsequent years.     

Non-invasive measurement of the physiological stress response of wild rabbits to the odour of a predator

Summary. Stress has been widely studied in different mammals, but the physiological stress reaction that the odour of a predator could induce in preys has not received much attention. Besides, not all the animals would respond to the same extent to a known stressor. We developed an experimental procedure with eleven na?ve European rabbits (Oryctolagus cuniculus) in order to determine the individual physiological response to the olfactory detection of a potential predator. The rabbits were housed singly in small enclosures with a concrete burrow system and food and water were available ad libitum. The animals followed a control trial, without odour, and an experimental trial where we confronted the rabbits with fox (Vulpes vulpes) odour. Furthermore, another sample of eleven rabbits followed a control procedure subjected to the same housing and handling procedures but without facing the predator odour. In order to assess the physiological response we analysed the concentration of glucocorticoid metabolites in the faeces of the rabbits. Therefore, everyday faecal samples were collected and analysed with an enzyme immunoassay in order to measure the corticosterone metabolites (CM), particularly, those metabolites with a 5α-3β, 11β-diol structure. After validating the assay for wild rabbits, we found that the simulated presence of a predator (fox odour) in the enclosure resulted in an increase in faecal CM concentrations. However, the stressor did not affect all the animals in the same way. We found a general increase in the individual differences. In particular, males experienced a higher increase than females, though the overall response was similar for both sexes. To our knowledge this is one of the first attempts to analyse the assessment of the risk of predation by means of non-invasive methods.     

The use of marked point processes in ecological and environmental forest studies

The paper presents new applications of marked point processes in forestry. The tools are pair correlation functions and mark connection functions. Studies of the structures of even-aged pine forests in Siberia show a tendency of development from clustering in young stands towards random distribution in elder stands for the trunk positions. The tree tops as the movable parts of trees are still more regular in old forests. Furthermore, in Siberian fir forests interesting tendencies of attraction between members of several tree classes are detected. Finally, studies of the distribution of damaged trees in some central European forests show that there the damaged trees appear as singletons; dominating trees are preferentially damaged.     

A comprehensive review of visual air quality at the Grand Canyon

The Grand Canyon, located in Northern Arizona, is one of the seven natural wonders of the world, and has been set aside as a National Park to preserve its unique character. Several million visitors from all over the world travel to the Grand Canyon each year to witness its awesome beauty, As a natural preserve, the area protects numerous values such as genetic diversity, solitude, non-mechanized recreation, etc, but the majority of visitors travel to the Grand Canyon for one reason: to view the scenery.There have been reports in the general press (and even in the United States Congressional Hearings) that visual conditions at the Grand Canyon have been seriously degraded by air pollution. Over the past nine years, a vast array of visibility-related research and monitoring has been conducted to determine the extent and probable cause of this visible degradation. Studies have included optical measurements, pollution characterization, source-receptor relationship analysis, and human perception of visual air quality. The resulting data document the visual air quality of the Grand Canyon and provide a basis to qualitatively and quantitatively evaluate significant events and trends.     

3-D numerical evaluation of density effects on tracer tests

In this paper we present numerical simulations carried out to assess the importance of density-dependent flow on tracer plume development. The scenario considered in the study is characterized by a short-term tracer injection phase into a fully penetrating well and a natural hydraulic gradient. The scenario is thought to be typical for tracer tests conducted in the field. Using a reference case as a starting point, different model parameters were changed in order to determine their importance to density effects. The study is based on a three-dimensional model domain. Results were interpreted using concentration contours and a first moment analysis. Tracer injections of 0.036 kg per meter of saturated aquifer thickness do not cause significant density effects assuming hydraulic gradients of at least 0.1%. Higher tracer input masses, as used for geoelectrical investigations, may lead to buoyancy-induced flow in the early phase of a tracer test which in turn impacts further plume development. This also holds true for shallow aquifers. Results of simulations with different tracer injection rates and durations imply that the tracer input scenario has a negligible effect on density flow. Employing model cases with different realizations of a log conductivity random field, it could be shown that small variations of hydraulic conductivity in the vicinity of the tracer injection well have a major control on the local tracer distribution but do not mask effects of buoyancy-induced flow.