The waterbirds of Parc National du Banc d’Arguin:Evaluation of all complete winter counts, workshop proceedings, and a future perspective

This is the report of an initiative to evaluate the results and methodology of all shorebird counts of the Banc d’Arguin in Mauritania. This was done by means of a workshop with all participants of the 2017 count expedition and a selection of researchers in the area, and an analysis of the 2017 census in the perspective of previous censuses. The goals of this initiative were (a) to gain more knowledge on the (causes of) temporal dynamics in the shorebird numbers at Banc d’Arguin, (b) to discuss the optimal design for future shorebird monitoring of the Banc d’Arguin, and (c) to improve the collaboration between all involved parties.Total bird numbers have been declining since the first complete census in 1980 (2,384,000 birds) with 1,725,000 birds counted in the 2017 census, a slightly higher total estimate than the previous census in 2014 (1,459,000 birds). All seven total censuses combined showed a significant temporal linear trend for six species (all negative, expect for one). For all other species, the data proved insufficient to determine temporal trends on the species level. An ordination analysis of all species per section suggests that species dependent on the intertidal mudflats decline more than species depending on the sublitoral and outer sea. Trends in population growth rates confirm this pattern.Discussions during and after the workshop led to a list of recommendations for future monitoring. To determine population trends, a complete count should be undertaken more frequently, by a trained Mauritanian team. Besides more data, this will lead to more experience and a better census. This is a preferred scenario, but it will take considerable investments, particularly in the installation of a permanent, skilled and motivated team of observers. Senior bird counters, trend analysis professionals, and a local guide should be involved to train this team. A course in count data analysis should be organised the Netherlands, and frequent training sessions should be organized in Mauritania, independent of the actual counts

Landscape-scale experiment demonstrates that Wadden Sea intertidal flats are used to capacity by molluscivore migrant shorebirds

P>1. Whether intertidal areas are used to capacity by shorebirds can best be answered by large-scale manipulation of foraging areas. The recent overexploitation of benthic resources in the western Dutch Wadden Sea offers such an 'experimental' setting. 2. We review the effects of declining food abundances on red knot Calidris canutus islandica numbers, based on a yearly large-scale benthic mapping effort, long-term colour-ringing and regular bird-counts from 1996 to 2005. We focus on the three-way relationships between suitable foraging area, the spatial predictability of food and red knot survival. 3. For each benthic sampling position, red knot intake rate (mg AFDM s-1) was predicted by a multiple prey species functional response model, based on digestive rate maximization (this model explained diet and intake rate in earlier studies on red knots). This enabled us to derive the spatial distribution of the suitable foraging area, which in each of the 10 years was analysed with a measure of autocorrelation, i.e. Moran's I. 4. Over the 10 years, when accounting for a threshold value to meet energetic demands, red knots lost 55% of their suitable foraging area. This ran parallel to a decrease in red knot numbers by 42%. Although there was also a decrease in patchiness (i.e. less information about the location of the suitable feeding sites), this did not yet lead to additional loss of birds. 5. To cope with these landscape-scale declines in food stocks, an increase in the capacity for instantaneous food processing would be required. Although we show that red knots indeed enlarged their muscular gizzards, the increase in gizzard size was not enough to compensate for the decreased feeding area. 6. Survival of islandica knots in the western Dutch Wadden Sea, based on colour-ring resightings, declined from 89% in the first half of our study period to 82% in the second half of our study period and could account for almost half of the decline in red knot numbers; the rest must have moved elsewhere in winter. 7. Densities of red knots per unit suitable foraging area remained constant at 10 knots ha-1 between 1996 and 2005, which suggests that red knots have been using the Dutch Wadden Sea to full capacity

Gpnmb is a potential marker for the visceral pathology in Niemann-Pick type C disease

Impaired function of NPC1 or NPC2 lysosomal proteins leads to the intracellular accumulation of unesterified cholesterol, the primary defect underlying Niemann-Pick type C (NPC) disease. In addition, glycosphingolipids (GSLs) accumulate in lysosomes as well. Intralysosomal lipid accumulation triggers the activation of a set of genes, including potential biomarkers. Transcript levels of Gpnmb have been shown to be elevated in various tissues of an NPC mouse model. We speculated that Gpnmb could serve as a marker for visceral lipid accumulation in NPC disease. We report that Gpnmb expression is increased at protein level in macrophages in the viscera of Npc1nih/nih mice. Interestingly, soluble Gpnmb was also found to be increased in murine and NPC patient plasma. Exposure of RAW264.7 macrophages to the NPC-phenotype-inducing drug U18666A also upregulated Gpnmb expression. Inhibition of GSL synthesis with the glucosylceramide synthase (GCS) inhibitor N-butyl-1-deoxynojirimycin prevented U18666A-induced Gpnmb induction and secretion. In summary, we show that Gpnmb is upregulated in NPC mice and patients, most likely due to GSL accumulation

Langjarige trends in aantallen wadvogels, in relatie tot de kokkelvisserij en het gevoerde beleid in deze; eindverslag EVA II (evaluatie schelpdiervisserij tweede fase) deelproject C2

Dit rapport beschrijft een analyse van de resultaten van circa 30 jaar hoogwater-vogeltellingen in de Waddenzee, tegen de achtergrond van de mechanische kokkelvisserij in dit gebied en het gevoerde beleid in deze, met name het sluiten van grote gebieden voor deze visserij in 1993. Deze maatregel heeft niet het gewenste effect gehad. De aantallen van de schelpdieretende soorten (Scholekster, Kanoet, Eidereend en Zilvermeeuw) zijn teruggelopen, die van de Scholekster nog het hardst in de gesloten gebieden (maar die van Kanoeten het hardst in de open gebieden). Hier staat een algemene toename van wormen-etende soorten wadvogels tegenover, die het sterkst is geweest in de open en gemengde gebieden. Meer succes lijken de meer recente, aanvullende gebiedssluitingen van 1998 te hebben gehad. Hierbij werden vooral rijke delen van het wad, waar zich mosselbanken begonnen te ontwikkelen, gesloten. Juist deze rijke delen bleken voor allerlei wadvogels, (schelpdier-eters, wormen-eters en ook vogels met een meer gemengd dieet) van groot belang en hier werden merendeels positieve ontwikkelingen in de aantallen gevonden

Changes in the waterbird community of the Parc National du Banc d'Arguin, Mauritania, 1980-2017

The Parc National du Banc d’Arguin in Mauritania hosts the largest concentrations of coastal waterbirds along the East Atlantic Flyway. In spite of this importance, a review of the changes in the numbers of waterbirds in the area is lacking since the first complete count in 1980. Here we analysed the seven complete waterbird counts made since then, and the additional yearly counts made in one subunit (Iwik region) since 2003.We present evidence for changes in the community composition of waterbirds over the past four decades. Total waterbird numbers showed a decrease between 1980 and 2017, with only Great White Pelican Pelecanus onocrotalus showing a significantincrease in numbers. Five species showed significant declines: Long-tailed Cormorant Phalacrocorax africanus, Red Knot Calidris canutus, Bar-tailed Godwit Limosa lapponica, Eurasian Curlew Numenius arquata, and Western Marsh Harrier Circus aeruginosus. In the remaining species, the variation in numbers between counts was too large, and the number of complete counts too small, for trends to be detected. The yearly counts at Iwik region also showed sharp decreases in the numbers of Red Knot, Bar-tailed Godwit, and Marsh Harrier, but not of Long-tailed Cormorant and Eurasian Curlew. A multivariate analysis revealed a significant effect of year on species composition, which was caused mainly by changes in the species depending on the intertidal mudflats for feeding (generally in decline) vs. the species depending on fish and crustaceans in the sublittoral and offshore zones (often showing increases)