Monitoring arthropods in a tropical landscape: relative effects of sampling methods and habitat types on trap catches

To discuss the challenge of monitoring multi-species responses of tropical arthropods to disturbance, we considered a large dataset (4 × 105 individuals; 1,682 morphospecies representing 22 focal taxa) based on the work of parataxonomists to examine the effects of anthropogenic disturbance on arthropods at Gamba, Gabon. Replication included three sites in each of four different stages of forest succession and land use after logging, surveyed during a whole year with four sampling methods: pitfall, Malaise, flight-interception and yellow pan traps. We compared the suitability of each sampling method for biological monitoring and evaluated statistically their reliability for 118 arthropod families. Our results suggest that a range of sampling methods yields more diverse material than any single method operated with high replication. Multivariate analyses indicated that morphospecies composition in trap catches was more strongly influenced by habitat type than by sampling methods. This implies that for multi-species monitoring, differences in trap efficiency between habitats may be neglected, as far as habitat types remain well contrasted. We conclude that for the purpose of monitoring large arthropod assemblages in the long-term, a protocol based on operating a set of different and non-disruptive traps appears superior in design than summing a series of taxa-specific protocols

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon¹⁻³. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses⁴⁻⁹. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc

Disciplina partidária e apoio ao governo no bicameralismo brasileiro

O artigo avalia a disciplina dos partidos políticos no poder Legislativo brasileiro e o apoio que proporcionam ao governo, sob uma perspectiva bicameral. Busco dois objetivos principais. O primeiro é o de incluir o Senado na discussão sobre o relacionamento entre o poder Executivo e o poder Legislativo no país, comparando-o com a Câmara dos Deputados. Em segundo lugar, procuro avaliar os partidos individualmente, levando em consideração as suas características peculiares, que não são inerentes ao sistema partidário. A análise foi feita a partir das votações nominais realizadas na Câmara dos Deputados e no Senado Federal no período de 1989 a 2008, comparando o comportamento dos partidos entre si e com eles mesmos, ao longo do tempo. A abordagem cross-section e longitudinal permitiu observar resultados até então não identificados pela literatura que trata do relacionamento entre o poder Executivo e o poder Legislativo no país. Apesar de reforçar a corrente da literatura que afirma serem os partidos coesos, disciplinados e previsíveis, argumento que eles diferem substancialmente entre si, seja em suas estratégias, seja em sua forma de articulação. Dada a elevada fragmentação e as características peculiares de cada um dos partidos, não parece apropriado falar-se em atributos sistêmicos, que se estendam para todos eles; menos ainda quando se leva em consideração as duas casas legislativas

National Sovereignty in the Belgian Constitution of 1831. On the Meaning(s) of Article 25

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