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We present a workflow to track icebergs in proglacial fjords using oblique time-lapse photos and the Lucas-Kanade optical flow algorithm. We employ the workflow at LeConte Bay, Alaska, where we ran five time-lapse cameras between April 2016 and September 2017, capturing more than 400 000 photos at frame rates of 0.5–4.0 min−1. Hourly to daily average velocity fields in map coordinates illustrate dynamic currents in the bay, with dominant downfjord velocities (exceeding 0.5 m s−1 intermittently) and several eddies. Comparisons with simultaneous Acoustic Doppler Current Profiler (ADCP) measurements yield best agreement for the uppermost ADCP levels (~ 12 m and above), in line with prevalent small icebergs that trace near-surface currents. Tracking results from multiple cameras compare favorably, although cameras with lower frame rates (0.5 min−1) tend to underestimate high flow speeds. Tests to determine requisite temporal and spatial image resolution confirm the importance of high image frame rates, while spatial resolution is of secondary importance. Application of our procedure to other fjords will be successful if iceberg concentrations are high enough and if the camera frame rates are sufficiently rapid (at least 1 min−1 for conditions similar to LeConte Bay).
Growing concern about the biodiversity crisis has led to a proliferation of conservation responses, but with wide variation between countries in the levels of engagement and investment. Much of this variation is inevitably attributed to differences between nations in wealth. However, the relationship between environmentalism and wealth is complex and it is increasingly apparent that other factors are also involved. We review hypotheses that have been developed to explain variation in broad environmentalism and show that many of the factors that explain such variation in individuals, such as wealth, age and experience, also explain differences between nation states. We then assess the extent to which these factors explain variation between nation states in responses to and investment in the more specific area of biodiversity conservation. Unexpectedly, quality of governance explained substantially more variation in public and state investment in biodiversity conservation than did direct measures of wealth. The results inform assessments of where conservation investments might most profitably be directed in the future and suggest that metrics relating to governance might be of considerable use in conservation planning.
The British countryside is renowned for its pastoral beauty: a rich mosaic of farmland, woodlands, hedgerows and winding lanes where biodiversity flourishes. Yet linger within this apparently serene landscape and you are likely to discover an equally rich mosaic of conflict, which can sometimes be bitter and acrimonious. We see conflicts emerge over a wide range of issues, such as the culling of badgers Meles meles to control disease in cattle, the impact of intensive farming techniques on biodiversity or the illegal killing of predators for the benefit of game species. As we see elsewhere in this book, such conflicts are not restricted to the UK; they occur worldwide. Conflicts differ in details and participants, but they are often similar in challenges and strategies for resolution.
Ecological arguments invariably are part of conservation conflicts. We need to understand what impacts our activities have on species and ecosystems. Typically, in conflicts, the information deficit model is followed (Burgess et al., 1998). This model holds that more expert knowledge (in our case ecological data) and better communication are needed to help raise awareness, develop effective policies and change people's behaviour. Ecology is therefore often seen as providing the necessary objective evidence to enable decisions to be made to address conservation conflict. Consider, for example, the situation of conflicts involving predators. Those whose livelihoods depend on prey species commonly perceive predators as threats. So, ecologists commonly ask if perceptions of impact match ecological data (Sillero-Zubiri et al., 2007; Dickman, 2010). To make a decision about predator management, we need to quantify predation levels, understand how predation varies in time and space and how predators impact prey populations. Once we understand these ecological interactions and impacts, we can then make predictions about when and where different interests may become incompatible and to initiate management decisions. Frequently there may be several different techniques available for reducing impact so we need to know the relative effectiveness of each (Smith et al., 2014). Ecological data and analysis can help us distinguish between the effectiveness of alternative management strategies (see Box 9).
The Sahel in West Africa is a major wintering area for many western Palearctic migrants. The breeding populations of many of these have declined over the past 50 years. However, there have been few intensive field studies on migrant ecology in the Sahel and these were generally within a very restricted area. Consequently our knowledge of the distribution of species within this extensive area and the habitat associations of these species is limited. Understanding these habitat associations is essential for the effective conservation management of populations. We brought together a group of experts and consulted a wider group by email to assess the main Sahelian habitat types used by 68 African-Eurasian migrant bird species. Those species that showed strongest declines during 1970–1990 were associated with more open habitats than those newly declining during 1990–2000, when declining species were associated with habitats with more shrubs and trees. Populations of species that winter in the Sahel are generally stable or increasing now as rainfall has increased and is now near the long-term average for the Sahel. Those which use the Sahel only as a staging area are, in many cases, in rapid decline at present.
Julius Wellhausen (1844–1918) first published this work in German in 1878. Reissued here is the 1885 English translation of a revised 1883 version. Intended as a multi-volume work, this first book now stands as a self-contained work. A biblical scholar and orientalist, Wellhausen was professor of theology at Greifswald (until resigning for reasons of conscience) and then professor at Halle, Marburg and Göttingen. An early exponent of scientific philology, he placed the Pentateuch in a historical-social context, setting aside theological traditions. In this work, he sets out his method and argues that the Pentateuch is a synthesis of four independent narratives. He then examines the history of worship, sacrifice, sacred feasts, priests, and the law in ancient Israel. Wellhausen is a central figure in modern biblical studies, his theory dominated scholarship for a century, and his pioneering work remains of great interest in the field.