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.     

Bose-Einstein condensation in dilute atomic gases

Bose-Einstein condensation is one of the most curious and fascinating phenomena in physics. It lies at the heart of such intriguing processes as superfluidity and superconductivity. However, in most cases, only a small part of the sample is Bose-condensed and strong interactions are present. A weakly interacting, pure Bose-Einstein condensate (BEC) has therefore been called the "holy grail of atomic physics". In 1995 this grail was found by producing almost pure BECs in dilute atomic gases. We review the experimental development that led to the realization of BEC in these systems and explain how BECs are now routinely produced in about 25 laboratories worldwide. The tremendous experimental progress of the past few years is outlined and a number of recent experiments show the current status of the field. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00114-001-0277-8.     

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...     

Nonideal breeding habitat selection: a mismatch between preference and fitness

The selection of breeding sites in heterogeneous habitats should ideally be based on cues closely reflecting habitat quality and thus predicting realized individual fitness. Using long-term population data and data on territory establishment of male Northern Wheatears (Oenanthe oenanthe), we examined whether territory characteristics linked to individual fitness (reproductive performance and survival) also were linked to territory preference. Breeding territories varied in their physical characteristics and their potential effects on reproductive performance, and this variation among territories was correlated from one year to the next. Of all measured territory characteristics (from the focal and the previous year) only territory field layer height predicted individual fitness, i.e., reproductive performance was higher in territories with permanently short rather than growing field layers. Territory preference, instead, was only linked to the size of territory aggregations, i.e., males settled earlier at territory sites sharing borders with several adjacent sites than at those with few or no adjacent sites. This mismatch between territory characteristics linked to fitness and those linked to territory preference was not explained by site fidelity or compensated for by the different fitness components measured. Because the results were not in agreement with an ecological trap scenario, where poor habitats are preferred over high-quality habitats, our results suggest a more general case of nonideal habitat selection. Whereas nonideal selection with respect to territory field layer height may be explained by its poor temporal predictability within the breeding season, the preference for territory aggregations is still open to alternative adaptive explanations. Our study suggests that nonideal habitat selection should be investigated by direct estimates of preferences (e.g., order of territory establishment) and their links to habitat characteristics and fitness components. Furthermore, we suggest that the probability of establishing a territory needs to be included as a factor influencing patterns of habitat selection.