Rural gentrification in Catalonia, Spain: A case study of migration, social change and conflicts in the Empordanet area

The intensity of rural depopulation in Catalonia has diminished since the 1980s. New population growth patterns are occurring in rural areas, basically due to immigration. Although there has been a certain awareness of the magnitude of this process and its territorial distribution, little is known about the protagonists in this immigration and the impact on rural municipalities. Results are presented from a study of the immigration process in a group of rural inland municipalities close to the Costa Brava, a Mediterranean coastal region with extensive tourism. The great beauty of the landscape and the existence of housing stock that is being abandoned but remains desirable have led to a population influx from Catalonia’s large urban areas, especially Barcelona, purchasing these homes as a primary or secondary residence.This has led to rehabilitation of the housing stock, but also to higher housing prices and the resulting exodus of the young local population that cannot afford them; a potential source of conflict between the local population and the newcomers. The study is based on census data and statistical records, as well as extensive fieldwork, including interviews with local residents, newcomers and key informants.     

Micropollutants in four Brazilian water reservoirs

The concern about emerging contaminants such as pharmaceuticals is growing, mainly due to the increased global consumption of synthetic chemicals and the potential risk to environmental and human health. Although developing countries may be hotspots of pharmaceutical pollution, the knowledge about the occurrence of pharmaceuticals is still limited and patchy. Brazil holds one of the largest freshwater volumes globally, yet, little is known about the occurrence of pharmaceuticals in reservoirs although they make up key water sources. The aim of this study was, therefore, to investigate micropollutant occurrence, mainly pharmaceuticals, in four freshwater reservoirs distributed in Brazil. Water samples were collected in the Curuá-Una (CUN, Amazon region), Chapéu D’Uvas (CDU, Atlantic Forest region), Funil (FUN, Atlantic Forest region), and Simplício (SIM, Atlantic Forest region) reservoirs. The occurrence of 28 different micropollutants, including 26 pharmaceuticals, was investigated with target analysis on a UHPLC-Orbitrap-MS/MS, and a non-target screening approach was performed on all water samples to identify the presence of additional contaminants. The highest micropollutant concentrations were observed in FUN and SIM, which are the reservoirs with the largest population size in the catchment. Only caffeine was detected in CDU and CUN, which are reservoirs less influenced by urbanization. Metformin was the pharmaceutical with the highest concentrations, reaching 2 191 ng L⁻¹ in FUN. The non-target screening identified 125 chemicals, of which most were pharmaceuticals. The numbers of compounds identified and which were above the LOQ were higher in FUN and SIM, in agreement with results from the target analysis. Metformin is the compound with the highest risk to affect FUN reservoir negatively, based on calculated risk quotients. Considering that the reservoirs are used for multiple purposes, including water supply, irrigation, and aquaculture, it is important to continue investigating micropollutant occurrence to guarantee environmental and human health.     

Early life history of the congrid eels gnathophis habenatus and G. incognitos in New Zealand waters

Larvae (leptocephali) of Gnathophis habenatus (Richardson, 1848) and G. incognitas Castle, 1963 occur off Castlepoint throughout most of the year (not sampled December‐February), In general they are smallest in late summer (March) and ilargest in mid‐spring (October‐November), with metamorphosis to the juvenile in early summer of the year of spawning. The two species therefore have a larval life of approximately 10 months. The early life of these two species in Australian waters, and of G. capensis (Kaup) off southern Africa, agrees well with these observations. Eel eggs collected in the East Cape region of New Zealand and tentatively identified as those of Gnathophis confirm the spawning times (March—April) suggested by the sizes of leptocephali.     

Kinematics of SDSS subdwarfs: structure and substructure of the Milky Way halo

We construct a new sample of ∼1700 solar neighbourhood halo subdwarfs from the Sloan Digital Sky Survey (SDSS), selected using a reduced proper-motion diagram. Radial velocities come from the SDSS spectra and proper motions from the light-motion curve catalogue of Bramich et al. Using a photometric parallax relation to estimate distances gives us the full phase-space coordinates. Typical velocity errors are in the range  30–50 km s⁻¹  . This halo sample is one of the largest constructed to date and the disc contamination is at a level of ≲1 per cent. This enables us to calculate the halo velocity dispersion to excellent accuracy. We find that the velocity dispersion tensor is aligned in spherical polar coordinates and that  (σ _r , σ_φ, σ_θ) = (143 ± 2, 82 ± 2, 77 ± 2) km s⁻¹  . The stellar halo exhibits no net rotation, although the distribution of   v _φ  shows tentative evidence for asymmetry. The kinematics are consistent with a mildly flattened stellar density falling with distance like   r ^−3.75  .
Using the full phase-space coordinates, we look for signs of kinematic substructure in the stellar halo. We find evidence for four discrete overdensities localized in angular momentum and suggest that they may be possible accretion remnants. The most prominent is the solar neighbourhood stream previously identified by Helmi et al., but the remaining three are new. One of these overdensities is potentially associated with a group of four globular clusters (NGC 5466, NGC 6934, M2 and M13) and raises the possibility that these could have been accreted as part of a much larger progenitor.     

高州水库优势轮虫的种群分布

高州水库(1988)发现的44种轮虫中有8种为优势种。它们是螺形龟甲轮虫、针簇多肢轮虫、圆筒异尾轮虫、奇异巨腕轮虫、裂痕龟纹轮虫、卡顿圆筒异尾轮虫、卵形彩胃轮虫和真翅多肢轮虫。它们中除奇异巨腕轮虫、裂痕龟纹轮虫和真翅多肢轮虫外,其余的种类全年出现。8种的种群密度为46.1个/升。它们的个体数量占轮虫总量的83.8%。一年中以夏、秋密度最高,分别占41.2%和39.6%,而春、冬密度最低,各为10.7%和8.5%。文中还讨论了这八种轮虫各种高峰形成的量适温幅以及它们的分布与水质的关系。     

The Influence of Population Density on the Mating System of Thalassoma pavo, a Protogynous Mediterranean Labrid Fish

Abstract. The aim of the present study is to determine the factor balancing the reproductive polymorphism obSérved in Thalassoma pavo , a Méditerranean labrid fish that shows two sexually distinct types of males: small gonochoristic males and large sex-changed males. Large males defend specific mating sites above which females come to spawn. In such a mating system (pair spawning performed only by large territorial males), small males almost never get the opportunity to spawn. In a similar situation, Thalassoma bifasciatum , a coral reef species, shows a change of its mating system due to the influence of population density. As the population density grows, the proportion of small males in the population increases until they are numerous enough to take over a mating site where they perform group spawns. Concerning Thalassoma pavo , neither the group spawning behavior nor any other factor has ever been described to explain the maintenance of the two types of males.     

大鹏湾夜光藻种群的季节变化和分布特征

于1990年3月－1992年6月对中国南海大鹏湾盐田附近海域的夜光藻种群动态及时空分布进行综合调查。结果表明，夜光藻种群的出现期间一般为每年的1－6月，最早是1991年的12月，数量高峰期为3－5月，种群密度的波动极为显著；调查期间共发生8次赤潮，且都发生在3月初至5月初；大鹏湾夜光藻赤潮的发生特点是，赤潮的发生和消失突然，持续时间短，一般不超过3d；调查海域夜光藻种群的空间分布模式为近岸的高于中央水域的，表面的高于底层的。     

Contemporary management issues confronting fisheries science

Stock collapses have occurred worldwide. The most frequently cited cause is over-fishing, suggesting that fisheries management has been ineffective in controlling exploitation rates. The progression of a fishery from an over-exploited to a collapsed state involves impairment of the reproductive capacity of the target species, i.e. recruitment over-fishing. In many cases, this occurs by reduction of the spawning stock biomass (SSB) through the systematic elimination of spawning components within a stock complex. While operational definitions of minimum levels of SSB have been developed, they have seldom been applied and never adopted in a Canadian groundfish management context. The answer to the question of how much is enough to perpetuate a stock under exploitation has been illusive. Serebryakov [J. Cons. Int. Explor. Mer, 47 (1990) 267] has advocated definition of critical levels of SSB based on survival rates (R/SSB). We review his method and discuss the utility of the approach. An alternative approach to the problem of estimating minimum SSB is through a fundamental revision of the traditional stock and recruitment relationship. Explicit theoretical SSB thresholds below which reproduction/recruitment is severely impaired based upon density-dependent mating success (or Allee effects) is considered a superior approach to the question of how much is enough because of its ecological grounding. However, the successful application of this approach will require re-definition of the space/time scales of the management unit. Finally, support is growing for the establishment of closed areas or “no-take zones” as an alternative approach to managing the problems of fishing a stock complex by enabling sub-populations to escape fishing. While the expected benefits of areas protected from fishing are numerous, clear demonstrations of benefits of such areas in marine temperate ecosystems are lacking. In fact, unintended negative consequences may result from such actions.     

辽东湾斑海豹历史种群数量的估计

辽东湾斑海豹(Phoca largha)在本世纪里由于过度捕杀,种群数量下降比较严重。本文利用1930～1990年的捕获统计数据,对1930年以来辽东湾斑海豹的种群数量变化进行了估计。该种群在30年代初有7100头,并于1940年达到最高峰8137头,40～70年代末,由于过度捕杀,种群数量几度下降,1979年只有2269头(以上结果依据R=0.09413的种群更替率算得)。经1979～1982年徘徊以后,该种群数量迅速回升,并达到50年代末期的水平。根据0.09413,0.1163的种群更替率,对生殖力及特定年龄的死亡率进行估计。结果表明,在高比例的雌性生殖力情况下,辽东湾斑海豹幼体死亡率低于52％,成体死亡率低于16％。