Effects of site-selection bias on estimates of biodiversity change

Estimates of biodiversity change are essential for the management and conservation of ecosystems. Accurate estimates rely on selecting representative sites, but monitoring often focuses on sites of special interest. How such site-selection biases influence estimates of biodiversity change is largely unknown. Site-selection bias potentially occurs across four major sources of biodiversity data, decreasing in likelihood from citizen science, museums, national park monitoring, and academic research. We defined site-selection bias as a preference for sites that are either densely populated (i.e., abundance bias) or species rich (i.e., richness bias). We simulated biodiversity change in a virtual landscape and tracked the observed biodiversity at a sampled site. The site was selected either randomly or with a site-selection bias. We used a simple spatially resolved, individual-based model to predict the movement or dispersal of individuals in and out of the chosen sampling site. Site-selection bias exaggerated estimates of biodiversity loss in sites selected with a bias by on average 300–400% compared with randomly selected sites. Based on our simulations, site-selection bias resulted in positive trends being estimated as negative trends: richness increase was estimated as 0.1 in randomly selected sites, whereas sites selected with a bias showed a richness change of −0.1 to −0.2 on average. Thus, site-selection bias may falsely indicate decreases in biodiversity. We varied sampling design and characteristics of the species and found that site-selection biases were strongest in short time series, for small grains, organisms with low dispersal ability, large regional species pools, and strong spatial aggregation. Based on these findings, to minimize site-selection bias, we recommend use of systematic site-selection schemes; maximizing sampling area; calculating biodiversity measures cumulatively across plots; and use of biodiversity measures that are less sensitive to rare species, such as the effective number of species. Awareness of the potential impact of site-selection bias is needed for biodiversity monitoring, the design of new studies on biodiversity change, and the interpretation of existing data.     

Planspiel zur neuen EU-Chemikalienpolitik (REACH) in NRW

Aim and Background

In 1999, under German Presidency, the European Council asked the European Commission to set up an approach with new instruments for a new European strategy on chemicals management. In 2001, the Commission subsequently published a White Paper called ‘Strategy for a future European chemicals policy’. After intensive discussions with all involved parties, a proposal for a new Regulation, called REACH, was brought in to Council and Parliament (co-decision procedure) in October 2003. Different impact assessments concerning the strategy of the White Paper presumed dramatically increasing costs for the chemical industry. Due to these discussions, the Government of North Rhine-Westphalia decided to conduct a pilot project on workability of the new requirements in the second half of 2003. The parties involved were administrations, producers, industrial associations, unions and NGOs. The focus was not to test the entire Regulation, but to analyse the practicability of selected processes, evaluations, and communication processes connected with the registration of substances.

Results

Examining the requirements and processes with regard to their realization in practice, resulted in a list of well-founded proposals. These proposals concern modification in the Regulation itself, implementation tools required, and guidelines which will need to be available before the REACH system is launched. The pivot questions of the pilot testing were the acceptance of data of substance-effects and their evaluation in different application areas. The registration Agency (played by the German Competent Authorities) checked the presented documents concerning completeness and plausibility. For all presented papers inquiries were needed In summary, the simulation has provided concrete evidence of where and why REACH may cause problems. Lack of simple instruments and corresponding knowledge for conducting exposition scenarios were noticed. The simulation process facilitated a new communication of all parties along the supply chain. In addition, the development of new networks could be observed to ease co-operation between authorities and those active on the market. These networks continue to exist even after cessation of the pilot trial.     

Climate Engagement in a Digital Age: Exploring the Drivers of Participation in Climate Discourse Online in the Context of COP21

Various scholars underscore the importance of public engagement with climate change to successfully respond to the challenges of global warming. However, although online media provide various new opportunities to actively engage in climate discourse so far very little is known about the drivers of this form of engagement. Against this background, this study tested a theoretical model on the effects of media and interpersonal communication on participation in climate discourse online using data from a representative online survey of German citizens (n?=?1392) carried out while COP21. Overall, the results show that receiving information on climate change from social media (social networks, Twitter, blogs), active information seeking online and interpersonal conversations about COP21 strongly encourage participation in climate discourse online. Moreover, results provide relevant insights on the role of interest in climate politics, personal issue relevance and climate scepticism as preconditions of communication effects.     

Arctic terrestrial biodiversity status and trends: A synopsis of science supporting the CBMP State of Arctic Terrestrial Biodiversity Report

Ambio - This review provides a synopsis of the main findings of individual papers in the special issue Terrestrial Biodiversity in a Rapidly Changing Arctic. The special issue was developed to...     

The alternative Pharaoh approach: stingless bees mummify beetle parasites alive

Workers from social insect colonies use different defence strategies to combat invaders. Nevertheless, some parasitic species are able to bypass colony defences. In particular, some beetle nest invaders cannot be killed or removed by workers of social bees, thus creating the need for alternative social defence strategies to ensure colony survival. Here we show, using diagnostic radioentomology, that stingless bee workers (Trigona carbonaria) immediately mummify invading adult small hive beetles (Aethina tumida) alive by coating them with a mixture of resin, wax and mud, thereby preventing severe damage to the colony. In sharp contrast to the responses of honeybee and bumblebee colonies, the rapid live mummification strategy of T. carbonaria effectively prevents beetle advancements and removes their ability to reproduce. The convergent evolution of mummification in stingless bees and encapsulation in honeybees is another striking example of co-evolution between insect societies and their parasites.     

Behavioural evidence of magnetoreception in dolphins: detection of experimental magnetic fields

Magnetoreception, meaning the perception of magnetic fields, is supposed to play an important role for orientation/navigation in some terrestrial and aquatic species. Although some spatial observations of free-ranging cetaceans’ migration routes and stranding sites led to the assumption that cetaceans may be sensitive to the geomagnetic field, experimental evidence is lacking. Here, we tested the spontaneous response of six captive bottlenose dolphins to the presentation of two magnetized and demagnetized controlled devices while they were swimming freely. Dolphins approached the device with shorter latency when it contained a strongly magnetized neodymium block compared to a control demagnetized block that was identical in form and density and therefore undistinguishable with echolocation. We conclude that dolphins are able to discriminate the two stimuli on the basis of their magnetic properties, a prerequisite for magnetoreception-based navigation.