The Bahama Warbler Setophaga flavescens is restricted to Grand Bahama and Abaco in the Bahamas Islands, where in recent decades its pine forest habitat has been seriously affected by hurricanes. To assess its conservation status and determine its habitat requirements, we conducted point transects with playback and simultaneously took measurements at 464 locations in pine forest across Grand Bahama from April to June 2018. Warbler presence was predicted by taller Thatch Palms Thrinax radiata and some fire disturbance, and its absence by a higher number of needleless pines. A comparison of these habitat predictors between the combined regions where warblers were detected (Lucayan Estates and East End) vs. where they were not (West End and Freeport) also revealed that Bahama Warblers showed a marked preference for taller Thatch Palms (>140 cm) and habitat plots within the middle fire disturbance category. These findings suggest that the species is adapted to a climax pine forest habitat maintained under a standard fire regime. Our research was intended to provide a first baseline study of the warbler’s distribution and ecology on Grand Bahama, but the distribution may have radically changed following Hurricane Dorian’s devastation of the island in 2019, and the species may now only survive on Abaco. Nevertheless, ecological insights from Grand Bahama seem likely to help conservation management on Abaco, but both islands now need to be surveyed.

The aim of the present study is to test the resource economic monopolization hypothesis and the hypothesis of monogamy using the shrimp Alpheus estuariensis as a model. The shrimps were collected in two areas in the Vaza-Barriz estuary, north-east Brazil, from August to November 2016. The average abundance of refuges was obtained through 30 random replicates. The shrimp presented a random distribution in both areas. Males and females found together showed a weak relation between their sizes, with males being larger than females. In addition, the cheliped of males grows proportionally more than that of females. The great abundance of refuges present in the environment, added to the aforementioned results, do not support the idea of refuge-guarding behaviour or monogamy. These results, which are in disagreement with those already found for some shrimps of the same family, genus, and even species, reinforce the idea that Alpheidae can be used as a model in the study of how environmental conditions are capable of shaping the social behaviour of a species.

Our spatial analysis indicates that in 2000 over one third of the rural population in developing countries was located on less favored agricultural land and areas, which are constrained by biophysical conditions or poor market access. We examine whether these spatial distributions of rural population in 2000 influence subsequent changes in the rate of poverty from 2000 to 2012 in 83 developing countries. We find no evidence of a direct impact on changes in poverty, but there is a significant indirect impact via the elasticity of poverty reduction with respect to growth. If climate change leads to more people concentrated in these areas, or an increase in unfavorable agricultural regions, then the poverty-reducing impact of overall per capita income growth could be further weakened. Reducing poverty will require targeting rural populations in less favored lands and remote areas and encouraging out-migration.

This paper proposes a methodology for quantifying the territorial impact on population distribution of the railway. The central hypothesis is that access to railway services provides the best-connected areas with a long-term comparative advantage over others that are less accessible. Carrying out a historical analysis and providing comparable data at the municipal level allows us to determine the extent to which the railway has fostered the concentration of population within its immediate surroundings. The case study presented here is that of Spain between 1900 and 2001, but the same methodology could equally be applied to any other country for which the required data are available. In this case, key data included a Geographic Information System with information about both the development of the railway network and census data relating to total population at the municipal level. The results obtained suggest the relevance of this methodology, which makes it possible to identify the periods and areas in which this influence was most significant.

The effect of landscape on populations is of great importance, especially given the number of species inhabiting patchy landscapes. Developments in geographical information systems are facilitating a greater application of spatial analyses to threatened species, such as the Endangered giant panda Ailuropoda melanoleuca, for which habitat patchiness and quality are key limiting factors. Of all factors that influence the suitability of habitat for the giant panda, topography is not subject to change. Here, we report a spatial and statistical analysis of the high quality topographic habitat preferred by the giant panda across its stronghold in the Qinling Mountains, China. High quality topographic habitat, as indicated by a combination of elevation, slope and aspect, covers 92,788 ha, accounting for 15% of the current range of the species. The distribution of the giant panda closely follows patterns of topography and areas with patches of high quality topographic habitat are strongly associated with areas supporting greater numbers of giant pandas. However, comparisons between our model and the existing reserve system reveals a number of inadequacies. Some of the reserves contain little high quality topographic habitat and many patches of high quality topographic habitat are unprotected. Given the importance of topography and the decisive role it plays in shaping habitat, landscapes containing high quality topographic features must be a critical consideration in the design of reserves for the giant panda. The existing system of nature reserves is heavily weighted towards judicial and administrative boundaries, to the detriment of other factors such as topography.

Introduction. There has been increasing interest in the domestication potential of indigenous fruit trees. Nevertheless, our understanding of how these species’ abundance and yield of fruit is altered by ecological conditions, which is critical to foresee realistic sustainable management plans, is limited. Materials and methods. We used local ecological knowledge, presence / absence data and quantitative methods to examine the effect of ecological conditions on the distribution, abundance and yields of tamarind trees (T. indica) across three ecological regions in Benin, West Africa. Results and discussion. Rural communities’ knowledge on the species’ ecological range was congruent with scientific findings. The natural distribution of tamarind individuals was limited to the Sudanian and the Sudano-Guinean regions and their density declined with increasing moisture, being highest (2 trees·km-2) in the Sudanian region and lowest in the Guineo-Congolian region (scarce). On the other hand, fruit and pulp mass and number of seeds per fruit varied significantly, being higher in the Guineo-Congolian wetter region. However, no significant variation occurred among ecological regions for estimated overall fruit yields per tree. This might indicate that tamarind trees tend to invest in a small number of very large fruits under wetter conditions and a very large number of small fruits under dryer conditions. Conclusion. The results showed that semi-arid lands would best suit T. indica domestication. Nevertheless, its productivity could be higher under wetter conditions. Because of its affinity for gallery forests, we recommend thorough studies on its capacity to survive the increasing drought in its current ecological range.

Introduction. La mineuse des agrumes Phyllocnistis citrella, introduite en 1994 en Tunisie, est un ravageur sténophage n'évoluant que sur jeunes pousses et lorsque les conditions thermiques sont favorables. Afin de pouvoir envisager par la suite une lutte intégrée contre P. citrella, nous avons étudié les relations entre la mineuse, ses ennemis naturels, le climat et la plante hôte. Matériel et méthodes. Le suivi des populations de la mineuse a été effectué sur citronniers et orangers de 1997 à 1999. Des échantillons constitués de pousses de différents âges ont été prélevés chaque semaine, puis examinés sous loupe binoculaire. Tous les stades pré-imaginaux morts ou vivants de la mineuse ont été dénombrés. L'émergence en laboratoire d'adultes de parasitoïdes a permis leur identification. Résultats. L'oranger présente trois poussées de sève : au printemps (février à avril), en été (juin à juillet) et en automne (mi-août à octobre). Les pousses de printemps sont les plus importantes (60 % du feuillage) mais sont peu attaquées par la mineuse ; les deux autres poussées végétatives, qui dépendent de la charge de l'arbre et des conditions climatiques ambiantes, sont à 100 % infestées et permettent le développement de huit générations successives de mineuses. Chez le citronnier, en revanche, des jeunes pousses sont émises presque toute l'année et permettent donc à P. citrella de s'y maintenir constamment et de développer jusqu'à 10 générations annuelles. Le taux de mortalité du ravageur dépend des fortes chaleurs de l'été, des basses températures, de la raréfaction de la ressource alimentaire et des ennemis naturels. Discussion et conclusion. L'impact de ces différents facteurs sur la régulation des populations de P. citrella en Tunisie est analysé et discuté.

Introduction. Depuis 1996, les dégâts de rouille argentée, occasionnés jusqu'alors par Hercinothrips femoralis Reuter, sont devenus très préjudiciables à la commercialisation. La présente étude a cherché à apporter quelques éléments sur le ravageur, sa dispersion et les méthodes de lutte. Matériel et méthodes. L'évolution des populations et des dégâts de rouille argentée a été suivie pendant un an, sur dix bananeraies sélectionnées. Des échantillons ont été prélevés sur ces plantations pour vérifier l'identification du thrips. Afin d'améliorer la lutte, des gaines standard et des gaines imprégnées d'insecticide (cyperméthrine ou fipronil) ont été testées. Résultats et discussion. Le thrips Elixothrips brevisetis Bagnall semble avoir remplacé H. femoralis. Il est aujourd'hui responsable des dégâts de rouille argentée en Martinique et capable de pulluler à tout moment de l'année sur l'ensemble de l'île. Les gaines standard ont permis de protéger 96 % des doigts, alors que, sur régimes non gainés, le taux de parasitisme a été de 98 %. Bien que les gaines imprégnées d'insecticide protègent 100 % des doigts, leur intérêt paraît limité en raison des contraintes qu'elles imposent. Conclusion. Dans la lutte contre ce ravageur, ce n'est pas le type de gaine mais la date de la pose qui est déterminante. Une gaine standard, posée au stade de la “ dernière main femelle découverte ”, paraît être le moyen le plus adapté pour protéger les régimes et, cela, sans utiliser d'intrant chimique.