Effects of Artificial Roosts for Frugivorous Bats on Seed Dispersal in a Neotropical Forest Pasture Mosaic

Abstract:  In the Neotropics ongoing deforestation is producing open and heavily fragmented landscapes dominated by agriculture, mostly plantations and cattle pastures. After some time agriculture often becomes uneconomical and land is abandoned. Subsequent habitat regeneration may be slow because seed inputs are restricted by a lack of incentives—such as suitable roost sites—for seed dispersers to enter deforested areas. Increasing environmental awareness has fostered growing efforts to promote reforestation. Practical and cost-efficient methods for kick-starting forest regeneration are, however, lacking. We investigated whether artificial bat roosts for frugivorous bat species can attract these key seed dispersers to deforested areas, thereby increasing seed rain. We installed artificial bat roosts in a forest-pasture mosaic in the Costa Rican Atlantic lowlands and monitored bat colonization and seed dispersal. Colonization occurred within a few weeks of installation, and 10 species of bats occupied the artificial roosts. Five species of frugivorous or nectarivorous bats colonized artificial roosts permanently in both primary habitat and in deforested areas, in numbers similar to those found in natural roosts. Seed input around artificial roosts increased significantly. Sixty-nine different seed types, mostly of early-successional plant species, were transported by bats to artificial roosts in disturbed habitats. The installation of artificial bat roosts thus successfully attracted frugivorous bats and increased seed inputs into degraded sites. This method is likely to speed up early-vegetation succession, which in turn will attract additional seed dispersers, such as birds, and provide a microhabitat for seeds of mid- and late-successional plants. As well as supporting natural forest regeneration and bat conservation, this cost-efficient method can also increase environmental awareness among landowners.     

Storm surges: perspectives and options

This review paper attempts to summarize the scattered and fragmented knowledge about past and possible future changing storm-surge statistics using the particularly well-studied case of the North Sea as an example. For this region, a complete and robust analysis methodology has been developed in recent years. This methodology is based on dynamical and statistical models. Using the concept of dynamical downscaling, development during recent decades, when sufficiently good and homogeneous weather data exist, has been “reconstructed,” and scenarios of possible future change are described. “Localization” allows estimation of changes at specific sites, e.g., harbors. As local water-level statistics depend not only on climate variations but also on local modifications of the local bathymetry, new options for adaptation emerge. For the case of Hamburg, an option for such future adaptations is discussed.     

Concentrations and sources of carbonaceous aerosol in the atmosphere of Summit,Greenland

High-volume PM_2.5 samples were collected at Summit, Greenland for approximately six months from late May through December of 2006. Filters were composited and analyzed for source tracer compounds. The individual organic compounds measured at Summit are orders of magnitude smaller than concentrations measured at other sites, including locations representative of remote oceanic, and remote and urban continental aerosol. The measured tracers were used to quantify the contribution of biomass burning (0.6–0.9 ng C m^?3), vegetative detritus (0.3–0.9 ng C m^?3), and fossil fuel combustion (0.1–0.8 ng C m^?3) sources, 4% of OC total, to atmospheric organic carbon concentrations at the remote location of Summit, Greenland. The unapportioned organic carbon (96%) during the early summer period correlates well with the fraction of water soluble organic carbon, indicating secondary organic aerosol as a large source of organic carbon, supported by the active photochemistry occurring at Summit. To the author's knowledge, this paper represents the first source apportionment results for the polar free troposphere.     

2nd Generation biofuels a sure bet? A life cycle assessment of how things could go wrong

Biofuels are heavily debated as to their potential to reduce transport-related greenhouse gas emissions. Life cycle thinking gave rise to formal evaluations of the energy balance of such fuels, which led to the vigorously conducted “corn to ethanol” debates. Just as consensus was building on such evaluations came the “carbon debt” insights, a result of applying consequential Life Cycle Assessment (LCA) backed by advanced economic modeling. Increasingly, hopes have shifted to the 2nd generation biofuels, viewed as a “technological home run”. Could this also backfire? We investigate a simple South African case in which there might not be improvements in environmental performance: a sugar mill sells its bagasse, currently used at low efficiency to provide process heat, to an advanced biofuels producer, and buys an equivalent amount of coal without investing in efficiency improvements. Seven scenarios are generated, ranging from the status quo, where no bagasse is diverted, to 100% bagasse diversion, with one scenario including an energy efficiency improvement in the sugar mill. A consequential LCA is applied to the seven scenarios, covering global warming potential (GWP), non-renewable energy use, aquatic eutrophication and terrestrial acidification. A basic financial analysis of the proposed scenarios shows that they are realistic, with potentially lucrative returns. Results show that diverting bagasse without efficiency improvements from its current use to an ethanol bio-refinery would indeed backfire for all environmental impacts studied. The base case outperforms all the other scenarios, with the 100% bagasse diversion scenario emerging the worst. Investments into energy efficiency are therefore a precondition for diverting cellulosic residues into biofuel production.     

First report on the uptake of automobile catalyst emitted palladium by European eels (Anguilla anguilla) following experimental exposure to road dust.

Following the introduction of automobile catalysts in the middle of the 1980s in Germany there is an increasing emission of the platinum-group-metals platinum, palladium (Pd) and rhodium. Still, it remains unclear if these metals are bioavailable for aquatic animals and to which extent they become accumulated by the aquatic biosphere. Because of analytical problems in detecting Pd in small biological samples the present investigation concentrates on the bioavailability of this metal. To answer the question of a Pd uptake by aquatic organisms experimental studies were conducted with European eels maintained in water containing road dust at a concentration of 10 kg/100 l. Following an exposure period of four weeks, samples of liver and kidney were analysed by total-reflection X-ray fluorescence analysis after co-precipitation of Pd with mercury. These experiments revealed an uptake of traffic related Pd by European eels which showed a mean liver Pd concentration of 0.18 +/- 0.05 ng/g (wet wt.), whereas the Pd concentration in the kidney ranged below the detection limit. Thus, in this study we can demonstrate for the first time that automobile catalyst emitted Pd is bioavailable for aquatic animals.     

Territory establishment in lekking marine iguanas, Amblyrhynchus cristatus: support for the hotshot mechanism

The territory establishment of male marine iguanas and their subsequent mating success were analysed to identify spatial spillover (hotshot) and temporal spillover effects on lek formation. Males started to establish small display territories 2 months ahead of the mating season. Males did not establish territories in temporal synchrony and did not settle at sites where the probability of encountering females was highest. However, males arriving later preferentially established their territories in the neighbourhood of already established territories independently of the density of female-sized iguanas in these territories. Although settling in close proximity, there were no fights between those males. The number of fights between territorial males increased towards, and peaked during, the mating season. Fights did not result in the transfer of space, indicating that space per se was no resource. Instead, fights were directed towards central (hotshot) males. These central males had higher mating success than marginal males. Female density during the time of territory establishment did not predict the mating success of males, because females changed their spatial preferences between early establishment and mating periods. Similarly, the areas where males achieved the highest numbers of copulations changed during 4 years of our study. Thus, there was no evidence for temporal spillover between subsequent seasons. However, most male-male interactions served to distract successful males and may lead to spatial spillover of females into territories of unsuccessful males. In marine iguanas, territorial establishment appears largely governed by hotshot processes.