345 research outputs found

    Balancing the Scales: Analyzing Motivation to Combine and Avoiding Impermissible Hindsight in 2023

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    Ecolabelling and Fisheries Management

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    RAFMS (Rapid Appraisal of Fisheries Managment Systems) designed by ICLARM is a semistructural research tool designed to quickly document and evaluate exisiting local-level fisheries management systems in a given coastal community. The results of RAFMS will provide direction for undertaking more formal research or quantitative surveys to describe institutional arrangements and performance. RAFMS is suited to the village level, or to a cluster of villages within a defined marine unit such as a bay. It's emphasis is on the evaluation of the rights and rules system governing the use of the fisheries resources at the local level. The approach is also participatory because it is designed for the joint use of RAFMS practitioners and local researchers in collaboration with local fishing communities. The mode of community participation, however, is consultative. This Version 1 of the guide was published with the anticipation of future feedback. Version 1 had been tested for two years prior to being published in collaboration with ICLARM's research partners at: Ulugan Bay and Binunsalian Bay in Palawan, Asia (Southeastern)-Philippines; and Nolloth Village at Saparua Isalnd in Indonesia

    Reciprocal relationships in collective flights of homing pigeons

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    Collective motion of bird flocks can be explained via the hypothesis of many wrongs, and/or, a structured leadership mechanism. In pigeons, previous studies have shown that there is a well-defined hierarchical structure and certain specific individuals occupy more dominant positions --- suggesting that leadership by the few individuals drives the behavior of the collective. Conversely, by analyzing the same data-sets, we uncover a more egalitarian mechanism. We show that both reciprocal relationships and a stratified hierarchical leadership are important and necessary in the collective movements of pigeon flocks. Rather than birds adopting either exclusive averaging or leadership strategies, our experimental results show that it is an integrated combination of both compromise and leadership which drives the group's movement decisions.Comment: 7 pages, 5 figure

    Implications of farmland expansion for species abundance, richness and mean body mass in African raptor communities

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    Funding: The cost of fieldwork was generously covered by The Peregrine Fund (USA) and the Royal Society for the Protection of Birds (UK).Globally, conversion of natural habitats to farmland poses the greatest extinction risk to birds, its consequences being especially pervasive in the case of large predators and scavengers, whose declines may trigger extensive cascading effects. Human population growth in sub-Saharan Africa is expected to drive a vast expansion in agricultural land by 2050, largely at the expense of pastoral land and savanna. The greatest expanse of suitable land yet to be converted to agriculture lies in East and Central Africa, including South Sudan, DRC and Tanzania. To gauge the effects of land conversion on raptor populations in this region we used road survey data from neighbouring Uganda, from which we determined linear encounter rates (birds seen 100 km−1; n = 33 species), and species richness (from 53 species). Encounter rates were much lower in pastoral land than in protected savanna (median difference: −41%; 23 species), and lower still in agricultural land (−90%; 24 species). These disparities were influenced by diet and body mass. For large eagles and vultures, encounter rates in agricultural land were 97% lower than in protected savanna (median of 12 species), whereas for smaller raptors they were 30% lower (12 species). Large, apex consumers were thus more vulnerable to farmland expansion, and this was reflected in the mean body mass of species encountered in savanna (1740 g), pastoral (995 g) and agricultural land (856 g). Body mass differences remained significant when vultures were excluded. Since threat status is linked to body mass, encounter rates for globally threatened and near-threatened species likewise showed a more pronounced deficit in farmland than those of least concern. Accordingly, pastoral and agricultural transects were less species-rich (10.6 and 6.7 raptor species 100 km−1, respectively) than savanna transects (13.2 species). Our findings suggest that the expansion of agricultural land in sub-Saharan Africa will reduce raptor populations in pastoral land and savanna by c. 50% and 90%, respectively. We propose that conservation efforts focus on identifying the causes of raptor population deficits in farmland, and on safeguarding tracts of unprotected, intact savanna, together with existing protected areas.PostprintPeer reviewe

    Densities and population sizes of raptors in Uganda’s conservation areas

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    Projected increases in Africa’s human population over the next 40 years point to further, large-scale conversion of natural habitats into farmland, with far-reaching consequences for raptor species, some of which are now largely restricted to protected areas (PAs). To assess the importance of PAs for raptors in Uganda, we conducted an annual road survey through savanna, pastoral and agricultural land during 2008–2015. Here, we present density estimates for 34 diurnal raptor species, 18 of which were encountered largely or entirely within PAs. These included seven out of eight globally threatened or near-threatened species surveyed. Based mainly on published demographic values, we converted density estimates (birds 100 km-2) to numbers of adult pairs, for 11 resident, savanna-dependent species. We then estimated adult population sizes within conservation areas (individual PAs and clusters of contiguous PAs), based on the area of savanna in each site. This suggested that two threatened residents, Martial Eagle Polemaetus bellicosus and Lappet-faced Vulture Torgos tracheliotos, have national breeding populations of just 90–120 pairs. A third, White-headed Vulture Trigonoceps occipitalis, may have a breeding population of just 22–32 pairs. In each case, at least 90% of pairs are thought to reside within Uganda’s five largest conservation areas. In three cases our estimates of pair density were markedly lower than in other studies, while in six cases they were broadly consistent with published findings, derived from more intensive survey methods. Further work is required to determine the accuracy of our estimates for individual conservation areas, and to assess the long-term viability of Uganda’s threatened raptor populations.PostprintPeer reviewe

    Waterbirds of the Murchison Falls–Albert Delta Wetland System, an important Ramsar site

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    The Murchison Falls–Albert Delta Wetland System Ramsar Site, declared in 2006, consists of the River Nile from the Murchison Falls up to and including a small part of Lake Albert. Before entering the lake, the river splits into three main channels passing through an extensive delta supporting a papyrus swamp; the Ramsar site also includes the land within a kilometre of the river banks, north and south. Most is within Murchison Falls National Park. The river, including the channels through the papyrus, supports large numbers of waterbirds of many species. For a year, we undertook monthly waterbird counts along the channels through the delta swamps, and on the section of Lake Albert within the Ramsar site. Overall, we recorded 78 waterbird species and the site regularly supports three globally and another seven nationally threatened species, including Shoebill Balaeniceps rex, Grey Crowned Crane Balearica regulorum and Papyrus Gonolek Laniarius mufumbiri. The site is also important for large numbers of White-winged Black Terns Chlidonias leucopterus on passage. Most of the larger species, such as White-faced Whistling Duck Dendrocygna viduata and Long-tailed Cormorant Microcarbo africanus rarely, if ever breed in this area, instead their numbers drop at the times when they are expected to breed, apparently elsewhere. A number of pairs of Fish Eagles Haliaeetus vocifer breed, and there is a small colony of African Darters Anhinga rufa. The large numbers of easily-seen birds attract increasing numbers of visitors, adding to the site’s value. Various industrial activities are planned within the watershed of this Ramsar Site, mainly associated with oil and gas, and our data are expected to provide baseline data for future monitoring of the site. Keywords:  Murchison, Ramsar, waterbirds, Ugand
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