Effects of Pioneer Tree Species Hyperabundance on Forest Fragments in Northeastern Brazil

Abstract: Despite many studies on fragmentation of tropical forests, the extent to which plant and animal communities are altered in small, isolated forest fragments remains obscure if not controversial. We examined the hypothesis that fragmentation alters the relative abundance of tree species with different vegetative and reproductive traits. In a fragmented landscape (670 km²) of the Atlantic Forest of northeastern Brazil, we categorized 4056 trees of 182 species by leafing pattern, reproductive phenology, and morphology of seeds and fruit. We calculated relative abundance of traits in 50 1‐ha plots in three types of forest configurations: forest edges, small forest fragments (3.4–83.6 ha), and interior of the largest forest fragment (3500 ha, old growth). Although evergreen species were the most abundant across all configurations, forest edges and small fragments had more deciduous and semideciduous species than interior forest. Edges lacked supra‐annual flowering and fruiting species and had more species and stems with drupes and small seeds than small forest fragments and forest interior areas. In an ordination of species similarity and life‐history traits, the three types of configurations formed clearly segregated clusters. Furthermore, the differences in the taxonomic and functional (i.e., trait‐based) composition of tree assemblages we documented were driven primarily by the higher abundance of pioneer species in the forest edge and small forest fragments. Our work provides strong evidence that long‐term transitions in phenology and seed and fruit morphology of tree functional groups are occurring in fragmented tropical forests. Our results also suggest that edge‐induced shifts in tree assemblages of tropical forests can be larger than previously documented.     

VALUING ECOSYSTEM SERVICES OF CHILEAN TEMPERATE RAINFORESTS

The Valdivian Rainforest Ecoregion (35°–48° S) in southern South America is among the ecosystems with highest conservation priority worldwide due to its rich diversity, degree of endemism, and critical conservation status. Temperate rainforests in this vast area are essential as source of biological resources and to maintain different ecosystem services which remain largely unmeasured and unvalued. Consequently, the benefits they provide are not reflected in decision-making regarding forest management and conservation. Based on existing studies and results from ongoing research we describe selected ecosystem services and provide estimates of their economic value. Timber benefits for secondary forests expressed as net present stumpage values were US$ 3742 ha⁻¹ and US$ 3093 ha⁻¹ for sustainable forest management (SFM) and unsustainable harvesting, respectively. Timber benefits for old growth forests␣equaled US$ 4546 ha⁻¹ and US$ 5718 ha⁻¹, for SFM and unsustainable harvesting, respectively, using an 8% discount rate. Annual benefits from recreation were US$ 1.6 ha⁻¹ and US$ 6.3 ha⁻¹ for the two most important national parks located in the study area. The annual value of maintaining soil fertility was US$ 26.3 ha⁻¹ using the replacement cost of nutrient losses due to soil erosion. The annual economic value of water supply for human consumption using the production function method was US$ 235 ha⁻¹. These results provide valuable information on the kind and magnitude of values that could be relevant in decision-making concerning conservation and management of native forests in the Valdivian Rainforest Ecoregion.     

Fish-Passage Facilities as Ecological Traps in Large Neotropical Rivers

Abstract:  At present most of the large rivers of South America are impounded. Management plans historically have relied on the construction of fish passages, specifically ladders, to mitigate the impact of these waterway blockages on fisheries and biodiversity. Nevertheless, the design of these facilities is not ecologically sound and they are not monitored continually. Consequently, the real role of South American fish passages in fisheries and biodiversity management is unclear and the results of some studies suggest that ladders are problematic in fish conservation. We examined the characteristics and negative aspects of fish passages within a larger context and considered the notion that these facilities are ecological traps in some Brazilian impoundments. Four conditions are required to characterize a fish passage as an ecological trap: (1) attractive forces leading fish to ascend the passage; (2) unidirectional migratory movements (upstream); (3) the environment above the passage has poor conditions for fish recruitment (e.g., the absence of spawning grounds and nursery areas); and (4) the environment below the passage has a proper structure for recruitment. When these conditions exist individuals move to poor-quality habitats, fitness is reduced, and populations are threatened. To exemplify this situation we analyzed two case studies in the upper Paraná River basin, Brazil, in which the four conditions were met and migratory fish populations were declining. If passages work as ecological traps, regional fisheries will be in danger of collapse and conservation policies toward biodiversity will become more difficult and ineffective. The situation demands the closing of the passage in conjunction with alternative management actions to preserve system functionality, especially the conservation of critical habitats downstream and the restoration of damaged habitats in the region.     

Effects of River Impoundment on Ecosystem Services of Large Tropical Rivers: Embodied Energy and Market Value of Artisanal Fisheries

Abstract:  Applying the ecosystem services concept to conservation initiatives or in managing ecosystem services requires understanding how environmental impacts affect the ecology of key species or functional groups providing the services. We examined effects of river impoundments, one of the leading threats to freshwater biodiversity, on an important ecosystem service provided by large tropical rivers (i.e., artisanal fisheries). The societal and economic importance of this ecosystem service in developing countries may provide leverage to advance conservation agendas where future impoundments are being considered. We assessed impoundment effects on the energetic costs of fisheries production (embodied energy) and commercial market value of the artisanal fishery of the Paraná River, Brazil, before and after formation of Itaipu Reservoir. High-value migratory species that dominated the fishery before the impoundment was built constituted a minor component of the contemporary fishery that is based heavily on reservoir-adapted introduced species. Cascading effects of river impoundment resulted in a mismatch between embodied energy and market value: energetic costs of fisheries production increased, whereas market value decreased. This was partially attributable to changes in species functional composition but also strongly linked to species identities that affected market value as a result of consumer preferences even when species were functionally similar. Similar trends are expected in other large tropical rivers following impoundment. In addition to identifying consequences of a common anthropogenic impact on an important ecosystem service, our assessment provides insight into the sustainability of fisheries production in tropical rivers and priorities for regional biodiversity conservation .     

Brazilian Experience in the Joint Development of Energy Resources

On the basis of the Brazilian experience, the author reviews the relevant aspects of negotiation between countries for the development of joint energy projects, as well as forms of organization and distribution of their respective costs and benefits. The factors which lead to a successful agreement between the parties were harmonious relations between the countries involved, willingness to negotiate, the ability to make concessions, a real interest in the project, whether for local consumption or for export, and the availability of technical and financial resources on the part of at least one of the partners. En se basant sur l'expérience faite par le Brésil, l'auteur passe en revue les aspects significatifs des négotiations entre pays pour la mise en valeur de projets énergétiques conjoints. Il etudie également les modes d'organisation et de distribution des coûts et avantages respectifs de ces projets. L'auteur cite les facteurs suivants qui dans le passé ont conduit à un accord satisfaisant entre les parties: relations harmonieuses entre pays concernés, désir de négocier, pouvoir de faire des concessions, intérêt réel porté au projet (qu'il soit conçu pour la consommation domestique ou l'exportation), moyens techniques et financiers de la part, au moins, d'un des partenaires. Basado en la experiencia brasileña, el autor pasa revista a los aspectos importantes en la negociación entre países para el desarrollo conjunto de proyectos de energía, así como sobre las formas de organización y distribución de los costos y beneficios. Los factores que condujeron a una negociación fructífera fuerion la relación armoniosa entre los países, deseo de negociar, disposición a hacer concesiones, interés real en el proyecto y la disponibilidad de tecnología y capacidad financiera en por lo menos uno de las partes.     

How working is defined: Structure and stability

Multidimensional scaling of statements that identify when individuals consider an activity in which one is engaged to be working was conducted on representative samples of the employed labor forces in Belgium, Germany, Japan and the U.S.A. at the time period 1982–1983 and again at the time period 1989–1992. Representative samples of the employed labor forces in East Germany, Bulgaria, the Czech Republic, Hungary, Poland, Slovakia and Beijing, China were studied at the time period 1991–1992 and were subjected to the same MDS analysis. The results provide empirical support that one hypothesized dimension underlying the way in which people define working ranges from burden/control to social contribution. Individuals who define working in burden/control and/or constraint terms emphasize costs to the individual. Individuals who define working largely in responsibility and exchange terms emphasize reciprocal exchange relations between the individual and the organization/society. Individuals who define working largely in social contribution terms emphasize the social benefits of working. The work definition structures in each of the four countries with replication samples are quite stable over time. In total, the work definition responses of over 18,000 individuals were studied.