Les donations

L'Avant-projet traite des donations en les présentant comme un des contrats nommés. La matière des libéralités, dans le projet de Code civil du Québec, est fragmentée entre les successions, pour les testaments, et les obligations, pour les donations. L'article présente une étude systématique et comparative avec le droit actuel de la législation proposée en la matière. Il souligne les aspects restés inchangés, les modifications apportées, les ambiguïtés ou lacunes des textes proposés. Pour ce faire, il a souvent fallu se référer à d'autres parties de l'Avant-projet, puisque les donations ne sont plus présentées que comme un contrat nommé parmi les autres. Mais la présentation suit le plan traditionnellement suivi par la doctrine en la matière : notion de libéralités, conditions de fond et deforme, effets des donations et enfin donations par contrat de mariage. Ceci permet de souligner pour chacun des points principaux les similitudes et différences avec le droit actuel selon une présentation connue des lecteurs. Ainsi, la notion de libéralité reste inchangée. On semble avoir voulu généraliser le don manuel à tous les biens meubles, sans qu'il soit certain, cependant, que l'on soit parvenu à ce résultat. On a omis d'émettre en plusieurs points les règles générales, laissant ainsi place à des difficultés d'application ou d'interprétation. lien est ainsi par exemple pour ce qui est de la forme des donations, de l'obligation aux dettes et de la définition des différents types de donation.The Draft Bill deals with gifts by presenting them as nominate contracts. Matters pertaining to liberalities in the proposed Québec Civil Code are divided between successions for wills and obligations for gifts. The article presents a systematic and comparative study of proposed legislation on gifts within the context of existing law. It underscores areas that remain unchanged, amendments made as well as ambiguities or omissions in proposed texts. To do this, it was often necessary to refer to other parts of the Drafts Bill, since gifts are only presented as being one nominate contract among other such contracts. Otherwise the presentation follows the traditional pattern found in doctrinal studies on the matter : the notion of liberality, conditions of substance and form, effects of gifts and, lastly, gifts by contract of marriage. This makes it possible to highlight each of the main points converging with or diverging from present law in a way that is familiar to readers. Thus the concept of liberality remains unchanged. There seems to have been a will to generalize the gift by delivery to all movable property — without it being evident that such result has been obtained. General rules have not been expounded into a sufficient number of points such that there may be room for difficulties in enforcement and interpretation. For instance, this occurs in matters pertaining to the form of gifts, obligations with regard to debts and the definition of varying types of gifts

The Geographic Distribution of Parasite-Induced Fruit Mimicry in Cephalotes atratus (Formicidae: Myrmicinae)

Parasite distributions fundamentally depend on the distributions of their hosts but may be more restricted than their hosts. Host-parasite symbioses tend to be spatially aggregated, and widely distributed host-parasite relationships are rare. Here, we combine field observations with published collection data to document the current known distribution of the nematode, Myrmeconema neotropicum, which infects the Neotropical canopy ant Cephalotes atratus. We report 6 new records from different Brazilian ecosystems, bringing the total number of independent observations of this interaction to 11. The broad distribution of these data points suggests that M. neotropicum infects C. atratus throughout its geographic range, although possible disturbance effects and specific habitat associations of the interaction remain unknown.Keywords: Host, Hymenoptera, Ants, Myrmeconema neotropicum, Rang

Gustavo Schwartz

ABSTRACT -Stressed plants are generally more attacked by galling insects. In this study we investigated the relationship between population abundance and species richness of galling insects on the tree Alchornea castaneaefolia A. JUSS. (Euphorbiaceae), submited to stress induced by the hemiparasite Psittacanthus sp. (Loranthaceae) in the Amazon, Brazil. Branches of A. castaneaefolia attacked by the hemiparasite were more heavily infested by galling insects than non-attacked branches. The field observations partially corroborate the hypothesis that there would be an optimal level of host-plant stress for galling insect establishment

Reconciling biome-wide conservation of an apex carnivore with land-use economics in the increasingly threatened Pantanal wetlands

Conservation of carnivores involves finding solutions to minimize habitat loss and human-wildlife conflict. Understanding the nature of land-use economics can allow us to mitigate both threats. In the Pantanal, the two main economic activities are cattle ranching and ecotourism, each of which directly and indirectly affect the persistence of jaguars (Panthera onca). To understand how the geography of these economic activities is related to jaguar populations, we developed a jaguar distribution model (JDM), livestock density model, and ecotourism lodge density model for the Pantanal. Due to the recent wildfires within the Pantanal, we also assess the impact of burnt areas that are suitable for jaguars, cattle ranching, and tourism. Our JDM indicate that 64% of the Pantanal holds suitable habitat for jaguars. However, jaguar habitat suitability was positively correlated with ecotourism, but negatively correlated with areas most suitable for intensive cattle-ranching. This demonstrates a biome-wide scenario compatible with jaguar conservation. Of particular concern, recent wildfires overlap most suitable areas for jaguars. If wildfires become increasingly frequent, this would represent a serious threat to jaguars and many other wildlife populations. We emphasize the global importance of the Pantanal wetland ecoregion as a key stronghold for long-term jaguar conservation

Asymmetric Dispersal and Colonization Success of Amazonian Plant-Ants Queens

The dispersal ability of queens is central to understanding ant life-history evolution, and plays a fundamental role in ant population and community dynamics, the maintenance of genetic diversity, and the spread of invasive ants. In tropical ecosystems, species from over 40 genera of ants establish colonies in the stems, hollow thorns, or leaf pouches of specialized plants. However, little is known about the relative dispersal ability of queens competing for access to the same host plants. We used empirical data and inverse modeling—a technique developed by plant ecologists to model seed dispersal—to quantify and compare the dispersal kernels of queens from three Amazonian ant species that compete for access to host-plants. We found that the modal colonization distance of queens varied 8-fold, with the generalist ant species (Crematogaster laevis) having a greater modal distance than two specialists (Pheidole minutula, Azteca sp.) that use the same host-plants. However, our results also suggest that queens of Azteca sp. have maximal distances that are four-sixteen times greater than those of its competitors. We found large differences between ant species in both the modal and maximal distance ant queens disperse to find vacant seedlings used to found new colonies. These differences could result from interspecific differences in queen body size, and hence wing musculature, or because queens differ in their ability to identify potential host plants while in flight. Our results provide support for one of the necessary conditions underlying several of the hypothesized mechanisms promoting coexistence in tropical plant-ants. They also suggest that for some ant species limited dispersal capability could pose a significant barrier to the rescue of populations in isolated forest fragments. Finally, we demonstrate that inverse models parameterized with field data are an excellent means of quantifying the dispersal of ant queens

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost