Sustainable Use of the Tropical Rain Forest: Evidence from the Avifauna in a Shifting-Cultivation Habitat Mosaic in the Colombian Amazon

We carried out a one-year study of the avifauna along a regeneration gradient created by indigenous shifting cultivation in the Colombian Amazon rain forest. Regenerating one-hectare crop fields, from 1 to 17 years after abandonment, and undisturbed understory sites were compared in a sample effort of 4323 net hours. We made 878 captures of 103 species belonging to 11 trophic groups. Differences in species richness and number of individuals captured between regenerating areas and primary forest were low. A comparison of similarity indices among the sites for each habitat type showed no consistent differences, suggesting similar levels of local heterogeneity. Similarity indices calculated between sites of different-aged habitats, however, showed that young secondary growth at less than 10 years of abandonment was least similar to other sites, whereas old secondary growth between 13 to 17 years of abandonment, and forest understories, had the most similar avifauna. Two trophic groups were absent from the samples of the forest interior, and the abundance of the other nine varied among sites of regeneration. We conclude that slash and burn agriculture represents a high-intensity, small-magnitude disturbance to the forest avifauna. Large changes occur when the crop field is established and last until about 10 years after abandonment. Our data suggest that abandoned crop fields older than this age mimic the natural patch dynamics of the forest, making this type of agriculture an example of a potentially sustainable use of tropical forests, at least from the standpoint of its impact on bird communities.     

Near-term ecological forecasting for dynamic aeroconservation of migratory birds

Near-term ecological forecasting has the potential to mitigate negative impacts of human modifications on wildlife by directing efficient action through relevant and timely predictions. We used the U.S. avian migration system to highlight ecological forecasting applications for aeroconservation. We used millions of observations from 143 weather surveillance radars to construct and evaluate a migration forecasting system for nocturnal bird migration over the contiguous United States. We identified the number of nights of mitigation required to reduce the risk of aerial hazards to 50% of avian migrants passing a given area in spring and autumn based on dynamic forecasts of migration activity. We also investigated an alternative approach, that is, employing a fixed conservation strategy based on time windows that historically capture 50% of migratory passage. In practice, during both spring and autumn, dynamic forecasts required fewer action nights compared with fixed window selection at all locations (spring: mean of 7.3 more alert days; fall: mean of 12.8 more alert days). This pattern resulted in part from the pulsed nature of bird migration captured in the radar data, where the majority (54.3%) of birds move on 10% of a migration season's nights. Our results highlight the benefits of near-term ecological forecasting and the potential advantages of dynamic mitigation strategies over static ones, especially in the face of increasing risks to migrating birds from light pollution, wind energy infrastructure, and collisions with structures.     

Is the WTO after your water? The General Agreement on Trade in Services (GATS) and poor people's right to water

The General Agreement on Trade in Services (GATS) seeks to expand international trade in a wide range of services ranging from tourism to telecommunications and education. In recent years, it has come under attack from civil society organizations in both the North and the South for having a detrimental impact on poor people's right to basic services. This article explores some of these controversies, using the example of water services. It focuses specifically on the impact of the GATS on poor people's right to water and national governments’ ability to safeguard the interests of poor people through regulation. It demonstrates that, de jure, the liberalization of water‐related services under the GATS may not necessarily undermine the ability of governments to introduce the kind of legislative measures necessary to realize poor people's right to water. Still, de facto, the exercise of policy autonomy might be substantially curtailed due to inherent ambiguities in treaty interpretation, the politics of process arising out of power asymmetries, a lack of transparency in processes of negotiation as well as institutional and other deficiencies in the domestic politics of WTO member states.     

Assessing societal costs associated with environmental impacts

A study of “harmless” odors was utilized as a platform for determining the cost impact of envi‐ronmental effects resulting from management decisions. The cost to society of “harmless” odors eventually leads to internal costs for companies emitting the odors. It is easier to determine societal costs for “harmless” odors than to estimate the internal costs that eventually accrue to a company. However, larger societal costs will lead to larger company costs; larger societal costs prob‐ably also lead to faster company internalization of costs.c 2000 John Wiley & Sons, Inc.     

De facto governance: how authoritative assessments construct climate engineering as an object of governance

ABSTRACT

Analyses of climate engineering (CE) governance have accelerated in the last decade. A key claim is that CE remains a largely ungoverned space, with shared norms, institutional arrangements, and formal rules to regulate CE not yet present. In contrast, here it is argued that de facto governance of CE is underway, discernible in an ordering of this nascent field of inquiry by unacknowledged sources of steering. One key source of de facto governance is analyzed: high-level ‘authoritative assessments’ of CE. The focus is on how these assessments are constructing CE as an object of governance through demarcating and categorizing this emerging field of inquiry, and how this contributes to normalizing and institutionalizing CE research (and CE research communities). Scrutinizing the distinct nature and political implications of de facto governance, particularly of novel and speculative technological trajectories not yet subject to formal steering, remains a key task for governance scholars.     

Mechanism-based explanations of impasses in the governance of ecosystem-based adaptation

Many climate change adaptation scholars recognise the complexities in the governance of adaptation. Most have used the concept of ‘barriers to adaptation’ in an attempt to describe why governance of adaptation is challenging. However, these studies have recently been critiqued for over simplifying complex governance processes by referring to the static concept of barriers, thereby ignoring dynamic complexity as a root explanatory cause. This paper builds the argument that how barriers are currently used in the literature is insufficient to explain why the governance of adaptation often proves difficult. We adopt a so-called mechanism-based approach to investigate how and why the governance of ecosystem-based adaptation (EbA) reaches impasses in five cases in Thailand and the Netherlands. Our findings show six causal mechanisms that explain impasses in the five case studies: (1) frame polarisation, (2) timing synchronisation, (3) risk innovation, (4) rules of the game, (5) veto players and (6) lost in translation. Several of these causal mechanisms are recurring and emerge under specific contextual conditions or are activated by other mechanisms. Our findings provide valuable insights into the impasses in the governance of EbA and allow for critical reflections on the analytical value of the mechanism-based approach in explaining why the governance of adaptation proves difficult and how this can be overcome.     

Combined effect of enzyme inducers and nitrate on selective lignin degradation in wheat straw by Ganoderma lobatum

Environmental Science and Pollution Research - Lignin is one of the main barriers to obtaining added-value products from cellulosic fraction of lignocellulosic biomass due to its random aromatic...     

Depth and muscle temperature of Pacific bluefin tuna examined with acoustic and pop-up satellite archival tags

Six Pacific bluefin tuna were tracked with ultrasonic telemetry and two with pop-up satellite archival tags (PSATs) in the eastern Pacific Ocean in 1997, 1998, and 1999. Both pressure and temperature ultrasonic transmitters were used to examine the behavior of the 2- to 4-year-old bluefin tuna. The bluefin spent over 80% of their time in the top 40 m of the water column and made occasional dives into deeper, cooler water. The mean slow-oxidative muscle temperatures of three fish instrumented with pressure and temperature transmitters were 22.0–26.1 °C in water temperatures that averaged 15.7–17.5 °C. The thermal excesses in slow-oxidative muscle averaged 6.2–8.6 °C. Variation in the temperature of the slow-oxidative muscle in the bluefin was not correlated with water temperature or swimming speeds. For comparison with the acoustic tracking data we examined the depth and ambient temperature of two Pacific bluefin tagged with pop-up satellite archival tags for 24 and 52 days. The PSAT data sets show depth and temperature distributions of the bluefin tuna similar to the acoustic data set. Swimming speeds calculated from horizontal distances with the acoustic data indicate the fish mean speeds were 1.1–1.4 fork lengths/s (FL s⁻¹). These Pacific bluefin spent the majority of their time in the top parts of the water column in the eastern Pacific Ocean in a pattern similar to that observed for yellowfin tuna. Received: 4 April 2000 / Accepted: 25 October 2000     

Uptake of 17β-estradiol and biomarker responses in brown trout (Salmo trutta) exposed to pulses

In streams, chemicals such as 17β-estradiol (E2) are likely to occur in pulses. We investigated uptake and biomarker responses in juvenile brown trout (Salmo trutta) of 3- or 6-h pulses of concentrations up to 370 ng E2 L⁻¹. Uptake by the fish was estimated from disappearance of E2 from tank water. A single 6-h pulse of 370 ng E2 L⁻¹ increased the plasma vitellogenin concentration, liver Erα- and vitellogenin-mRNA. Exposure to 150-160 ng E2 L⁻¹ for 6 h increased vitellogenin in one experiment but not in another. Two 6-h pulses had a larger effect one pulse. Brown trout in the size range 24-74 g took up E2 linearly with time and exposure concentration with a concentration ratio rate of 20.2 h⁻¹. In conclusion, the threshold for induction of estrogenic effects in juvenile brown trout at short term pulse exposure appears to be in the range 150-200 ng E2 L⁻¹.