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1. Analysing ethnobotanical and fishery-related importance of mangroves of the East-Godavari Delta (Andhra Pradesh, India) for conservation and management purposes

Author

Ravishankar T, Depommier D, Rönnbäck P, Lo Seen D, Collin S, Dahdouh-Guebas F, and Koedam N

Subjects
Other systems of medicine, RZ201-999, Botany, QK1-989
Abstract

Abstract Mangrove forests, though essentially common and wide-spread, are highly threatened. Local societies along with their knowledge about the mangrove also are endangered, while they are still underrepresented as scientific research topics. With the present study we document local utilization patterns, and perception of ecosystem change. We illustrate how information generated by ethnobiological research can be used to strengthen the management of the ecosystem. This study was conducted in the Godavari mangrove forest located in the East-Godavari District of the state Andhra Pradesh in India, where mangroves have been degrading due to over-exploitation, extensive development of aquaculture, and pollution from rural and urbanized areas (Kakinada). One hundred interviews were carried out among the fisherfolk population present in two mangrove zones in the study area, a wildlife sanctuary with strong conservation status and an adjacent zone. Results from the interviews indicated that Avicennia marina (Forsk.) Vierh., a dominant species in the Godavari mangroves, is used most frequently as firewood and for construction. Multiple products of the mangrove included the bark of Ceriops decandra (Griff.) Ding Hou to dye the fishing nets and improve their durability, the bark of Aegiceras corniculatum (L.) Blanco to poison and catch fish, and the leaves of Avicennia spp. and Excoecaria agallocha L. as fodder for cattle. No medicinal uses of true mangrove species were reported, but there were a few traditional uses for mangrove associates. Utilization patterns varied in the two zones that we investigated, most likely due to differences in their ecology and legal status. The findings are discussed in relation with the demographic and socio-economic traits of the fisherfolk communities of the Godavari mangroves and indicate a clear dependency of their livelihood on the mangrove forest. Reported changes in the Godavari mangrove cover also differed in the two zones, with significantly less perceptions of a decrease in the protected area, as compared to the adjacent non-protected area. A posteriori comparisons between sequential satellite imagery (retrospective till 1977) and respondents that were at least 15 years back then, revealed a mangrove decrease which was however perceived to different extents depending on the area with which the fishermen were familiar. While local needs had not been incorporated in the existing policy, we created a framework on how data on ethnobotanical traditions, fishery-related activities and local people's perceptions of change can be incorporated into management strategies.

Published
2006
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2. IUCN Red List of Ecosystems, Mangroves of the Western Indian Ocean

Author

Okello, J.A., primary, Koedam, N., additional, Di Nitto, D., additional, Dahdouh-Guebas, F., additional, Van der Stocken, T., additional, Hugé, J., additional, Fratini, S., additional, Cannicci, S., additional, Duncan, C., additional, Golléty, C., additional, Hamza, A.J., additional, Macamo, C., additional, Nicolau, D., additional, Rasolofomanana, L., additional, Savourey, G., additional, Wang’ondu, V., additional, and Suarez, Ena, additional

Published
2024
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6. Association of Hospital Volume with Perioperative Mortality of Endovascular Repair of Complex Aortic Aneurysms: A Nationwide Cohort Study

Author

Alberga, Anna J., von Meijenfeldt, Gerdine C. I., Rastogi, Vinamr, de Bruin, Jorg L., Wever, Jan J., van Herwaarden, Joost A., Hamming, Jaap F., Hazenberg, Constantijn E. V. B., van Schaik, Jan, Mees, Barend M. E., van der Laan, Maarten J., Zeebregts, Clark J., Schurink, Geert W. H., Verhagen, Hence J. M., van den Akker, P. J., Akkersdijk, G. P., Akkersdijk, W. L., van Andringa de Kempenaer, M. G., Arts, C. H. P., Avontuur, A. M., Bakker, O. J., Balm, R., Barendregt, W. B., Bekken, J. A., Bender, M. H. M., Bendermacher, B. L. W., van den Berg, M., Beuk, R. J., Blankensteijn, J. D., Bode, A. S., Bodegom, M. E., van der Bogt, K. E. A., Boll, A. P. M., Booster, M. H., Borger van der Burg, B. L. S., de Borst, G. J., Bos-van Rossum, W. T. G. J., Bosma, J., Botman, J. M. J., Bouwman, L. H., Brehm, V., de Bruijn, M. T., de Bruin, J. L., Brummel, P., van Brussel, J. P., Buijk, S. E., Buimer, M. G., Buscher, H. C. J. L., Cancrinus, E., Castenmiller, P. H., Cazander, G., Cuypers, P. W. M., Daemen, J. H. C., Dawson, I., Dierikx, J. E., Dijkstra, M. L., Diks, J., Dinkelman, M. K., Dirven, M., Dolmans, D. E. J. G. J., van Dortmont, L. M. C., Drouven, J. W., van der Eb, M. M., Eefting, D., van Eijck, G. J. W. M., Elshof, J. W. M., Elsman, A. H. P., van der Elst, A., van Engeland, M. I. A., van Eps, G. S., Faber, M. J., de Fijter, W. M., Fioole, B., Fritschy, W. M., Fung Kon Jin, P. H. P., Geelkerken, R. H., van Gent, W. B., Glade, G. J., Govaert, B., Groenendijk, R. P. R., de Groot, H. G. W., van den Haak, R. F. F., de Haan, E. F. A., Hajer, G. F., Hamming, J. F., van Hattum, E. S., Hazenberg, C. E. V. B., Hedeman Joosten, P. P. A., Helleman, J. N., van der Hem, L. G., Hendriks, J. M., van Herwaarden, J. A., Heyligers, J. M. M., Hinnen, J. W., Hissink, R. J., Ho, G. H., den Hoed, P. T., Hoedt, M. T. C., van Hoek, F., Hoencamp, R., Hoffmann, W. H., Hoksbergen, A. W. J., Hollander, E. J. F., Huisman, L. C., Hulsebos, R. G., Huntjens, K. M. B., Idu, M. M., Jacobs, M. J. H. M., van der Jagt, M. F. P., Jansbeken, J. R. H., Janssen, R. J. L., Jiang, H. H. L., de Jong, S. C., Jongbloed-Winkel, T. A., Jongkind, V., Kapma, M. R., Keller, B. P. J. A., Jahrome, A. Khodadade, Kievit, J. K., Klemm, P. L., Klinkert, P., Koedam, N. A., Koelemaij, M. J. W., Kolkert, J. L. P., Koning, G. G., Koning, O. H. J., Konings, R., Krasznai, A. G., Kropman, R. H. J., Kruse, R. R., van der Laan, L., van der Laan, M. J., van Laanen, J. H. H., van Lammeren, G. W., Lamprou, D. A. A., Lardenoije, J. H. P., Lauret, G. J., Leenders, B. J. M., Legemate, D. A., Leij-Dekkers, V. J., Lemson, M. S., Lensvelt, M. M. A., Lijkwan, M. A., van der Linden, F. T. P. M., Lung, P. F. L., Loos, M. J. A., Loubert, M. C., van de Luijtgaarden, K. M., Mahmoud, D. E. A. K., Manshanden, C. G., Mat-Tens, E. C. J. L., Meerwaldt, R., Mees, B. M. E., Menting, T. P., Metz, R., de Mol van Otterloo, J. C. A., Molegraaf, M. J., Montauban van Swijn-Dregt, Y. C. A., Morak, M. J. M., van de Mortel, R. H. W., Mulder, W., Nagesser, S. K., Naves, C. C. L. M., Nederhoed, J. H., Nevenzel, A. M., de Nie, A. J., Nieuwenhuis, D. H., van Nieuwenhuizen, R. C., Nieuwenhui-Zen, J., Nio, D., Oomen, A. P. A., Oranen, B. I., Oskam, J., Palamba, H. W., Peppelenbosch, A. G., van Petersen, A. S., Petri, B. J., Pierie, M. E. N., Ploeg, A. J., Pol, R. A., Ponfoort, E. D., Poyck, P. P. C., Prent, A., ten Raa, S., Raymakers, J. T. F. J., Reichmann, B. L., Reijnen, M. M. P. J., de Ridder, J. A. M., Rijbroek, A., van Rijn, M. J. E., de Roo, R. A., Rouwet, E. V., Saleem, B. R., van Sambeek, M. R. H. M., Samyn, M. G., van't Sant, H. P., van Schaik, J., van Schaik, P. M., Scharn, D. M., Scheltinga, M. R. M., Schepers, A., Schlejen, P. M., Schlösser, F. J. V., Schol, F. P. G., Scholtes, V. P. W., Schouten, O., Schreve, M. A., Schurink, G. W. H., Sikkink, C. J. J. M., te Slaa, A., Smeets, H. J., Smeets, L., Smeets, R. R., de Smet, A. A. E. A., Smit, P. C., Smits, T. M., Snoeijs, M. G. J., Sondakh, A. O., Speijers, M. J., van der Steenhoven, T. J., van Sterkenburg, S. M. M., Stigter, D. A. A., Stokmans, R. A., Strating, R. P., Stultiëns, G. N. M., Sybrandy, J. E. M., Teijink, J. A. W., Telgenkamp, B. J., Testroote, M. J. G., Tha-in, T., The, R. M., Thijsse, W. J., Thomassen, I., Tielliu, I. F. J., van Tongeren, R. B. M., Toorop, R. J., Tournoij, E., Truijers, M., Türkcan, K., Nolthenius, R. P. Tutein, Ünlü, C., Vaes, R. H. D., Vahl, A. C., Veen, E. J., Veger, H. T. C., Veldman, M. G., Verhagen, H. J. M., Verhoeven, B. A. N., Vermeulen, C. F. W., Vermeulen, E. G. J., Vierhout, B. P., van der Vijver-Coppen, R. J., Visser, M. J. T., van der Vliet, J. A., van Vlijmen-van Keulen, C. J., van der Vorst, J. R., Vos, A. W. F., Vos, C. G., Vos, G. A., de Vos, B., Voûte, M. T., Vriens, B. H. R., Vriens, P. W. H. E., de Vries, D. K., de Vries, J. P. P. M., de Vries, M., de Vries, A. C., van der Waal, C., Waasdorp, E. J., de Vries, B. M. Wallis, van Walraven, L. A., van Wanroi, J. L., Warlé, M. C., van Weel, V., van Well, A. M. E., Welten, G. M. J. M., Wever, J. J., Wiersema, A. M., Wikkeling, O. R. M., Willaert, W. I. M., Wille, J., Willems, M. C. M., Willigendael, E. M., Wilschut, E. D., Wisselink, W., Witte, M. E., Wittens, C. H. A., Wong, C. Y., Yazar, O., Yeung, K. K., Zeebregts, C. J. A. M., van Zeeland, M. L. P., Physiology, ACS - Pulmonary hypertension & thrombosis, Surgery, ACS - Atherosclerosis & ischemic syndromes, ACS - Microcirculation, VU University medical center, AII - Inflammatory diseases, APH - Digital Health, Medical Biochemistry, ACS - Diabetes & metabolism, AII - Infectious diseases, and AGEM - Amsterdam Gastroenterology Endocrinology Metabolism

Subjects
volume-outcome, complex AAA, endovascular, mortality
Abstract

Objective: We evaluate nationwide perioperative outcomes of complex EVAR and assess the volume-outcome association of complex EVAR. Summary of Background Data: Endovascular treatment with fenestrated (FEVAR) or branched (BEVAR) endografts is progressively used for excluding complex aortic aneurysms (complex AAs). It is unclear if a volumeoutcome association exists in endovascular treatment of complex AAs (complex EVAR). Methods: All patients prospectively registered in the Dutch Surgical Aneurysm Audit who underwent complex EVAR (FEVAR or BEVAR) between January 2016 and January 2020 were included. The effect of annual hospital volume on perioperative mortality was examined using multivariable logistic regression analyses. Patients were stratified into quartiles based on annual hospital volume to determine hospital volume categories. Results: We included 694 patients (539 FEVAR patients, 155 BEVAR patients). Perioperative mortality following FEVAR was 4.5% and 5.2% following BEVAR. Postoperative complication rates were 30.1% and 48.7%, respectively. The first quartile hospitals performed

Published
2023

9. Treatment Outcome Trends for Non-Ruptured Abdominal Aortic Aneurysms: A Nationwide Prospective Cohort Study

Author

Alberga, Anna J., Karthaus, Eleonora G., Wilschut, Janneke A., de Bruin, Jorg L., Akkersdijk, George P., Geelkerken, Robert H., Hamming, Jaap F., Wever, Jan J., Verhagen, Hence J. M., van den Akker, P. J., Akkersdijk, G. P., Akkersdijk, W. L., van Andringa de Kempenaer, M. G., Arts, C. H. P., Avontuur, A. M., Bakker, O. J., Balm, R., Barendregt, W. B., Bekken, J. A., Bender, M. H. M., Bendermacher, B. L. W., van den Berg, M., Beuk, R. J., Blankensteijn, J. D., Bode, A. S., Bodegom, M. E., van der Bogt, K. E. A., Boll, A. P. M., Booster, M. H., Borger van der Burg, B. L. S., de Borst, G. J., Bos-van Rossum, W. T. G. J., Bosma, J., Botman, J. M. J., Bouwman, L. H., Brehm, V., de Bruijn, M. T., de Bruin, J. L., Brummel, P., van Brussel, J. P., Buijk, S. E., Buimer, M. G., Buscher, H. C. J. L., Cancrinus, E., Castenmiller, P. H., Cazander, G., Cuypers, P. H. W. M., Daemen, J. H. C., Dawson, I., Dierikx, J. E., Dijkstra, M. L., Diks, J., Dinkelman, M. K., Dirven, M., Dolmans, D. E. J. G. J., van Dortmont, L. M. C., Drouven, J. W., van der Eb, M. M., Eefting, D., van Eijck, G. J. W. M., Elshof, J. W. M., Elsman, B. H. P., van der Elst, A., van Engeland, M. I. A., van Eps, G. S., Faber, M. J., de Fijter, W. M., Fioole, B., Fritschy, W. M., Jin, P. H. P. F. K., Geelkerken, R. H., van Gent, W. B., Glade, G. J., Govaert, B., Groenendijk, R. P. R., de Groot, H. G. W., van den Haak, R. F. F., de Haan, E. F. A., Hajer, G. F., Hamming, J. F., van Hattum, E. S., Hazenberg, C. E. V. B., Hedeman Joosten, P. P. H. A., Helleman, J. N., van der Hem, L. G., Hendriks, J. M., van Herwaarden, J. A., Heyligers, J. M. M., Hinnen, J. W., Hissink, R. J., Ho, G. H., den Hoed, P. T., Hoedt, M. T. C., van Hoek, F., Hoencamp, R., Hoffmann, W. H., Hoksbergen, A. W. J., Hollander, E. J. F., Huisman, L. C., Hulsebos, R. G., Huntjens, K. M. B., Idu, M. M., Jacobs, M. J. H. M., van der Jagt, M. F. P., Jansbeken, J. R. H., Janssen, R. J. L., Jiang, H. H. L., de Jong, S. C., Jongbloed-Winkel, T. A., Jongkind, V., Kapma, M. R., Keller, B. P. J. A., Jahrome, A. K., Kievit, J. K., Klemm, P. L., Klinkert, P., Koedam, N. A., Koelemaij, M. J. W., Kolkert, J. L. P., Koning, G. G., Koning, O. H. J., Konings, R., Krasznai, A. G., Kropman, R. H. J., Kruse, R. R., van der Laan, L., van der Laan, M. J., van Laanen, J. H. H., van Lammeren, G. W., Lamprou, D. A. A., Lardenoije, J. H. P., Lauret, G. J., Leenders, B. J. M., Legemate, D. A., Leijdekkers, V. J., Lemson, M. S., Lensvelt, M. M. A., Lijkwan, M. A., van der Linden, F. T. H. P. M., Lung, P. F. Liqui, Loos, M. J. A., Loubert, M. C., van de Luijtgaarden, K. M., Mahmoud, D. E. A. K., Manshanden, C. G., Mattens, E. C. J. L., Meerwaldt, R., Mees, B. M. E., Menting, T. P., Metz, R., de Mol van Otterloo, J. C. A., Molegraaf, M. J., Montauban van Swijndregt, Y. C. A., Morak, M. J. M., van de Mortel, R. H. W., Mulder, W., Nagesser, S. K., Naves, C. C. L. M., Nederhoed, J. H., Nevenzel, A. M., de Nie, A. J., Nieuwenhuis, D. H., van Nieuwenhuizen, R. C., Nieuwenhuizen, J., Nio, D., Oomen, A. P. A., Oranen, B. I., Oskam, J., Palamba, H. W., Peppelenbosch, A. G., van Petersen, A. S., Petri, B. J., Pierie, M. E. N., Ploeg, A. J., Pol, R. A., Ponfoort, E. D., Poyck, P. P. C., Prent, A., Raa, S. ten, Raymakers, J. T. F. J., Reichmann, B. L., Reijnen, M. M. P. J., de Ridder, J. A. M., Rijbroek, A., van Rijn, M. J. E., de Roo, R. A., Rouwet, E. V., Saleem, B. R., van Sambeek, M. R. H. M., Samyn, M. G., van ’t Sant, H. P., van Schaik, J., van Schaik, P. M., Scharn, D. M., Scheltinga, M. R. M., Schepers, A., Schlejen, P. M., Schlösser, F. J. V., Schol, F. P. G., Scholtes, V. P. W., Schouten, O., Schreve, M. A., Schurink, G. W. H., Sikkink, C. J. J. M., Slaa, A. te, Smeets, H. J., Smeets, L., Smeets, R. R., de Smet, A. A. E. A., Smit, P. C., Smits, T. M., Snoeijs, M. G. J., Sondakh, A. O., Speijers, M. J., van der Steenhoven, T. J., van Sterkenburg, S. M. M., Stigter, D. A. A., Stokmans, R. A., Strating, R. P., Stultiëns, G. N. M., Sybrandy, J. E. M., Teijink, J. A. W., Telgenkamp, B. J., Testroote, M. J. G., Tha-in, T., The, R. M., Thijsse, W. J., Thomassen, I., Tielliu, I. F. J., van Tongeren, R. B. M., Toorop, R. J., Tournoij, E., Truijers, M., Türkcan, K., Tutein Nolthenius, R. P., Ünlü, C., Vaes, R. H. D., Vahl, A. C., Veen, E. J., Veger, H. T. C., Veldman, M. G., Verhagen, H. J. M., Verhoeven, B. A. N., Vermeulen, C. F. W., Vermeulen, E. G. J., Vierhout, B. P., van der Vijver-Coppen, R. J., Visser, M. J. T., van der Vliet, J. A., van Vlijmen - van Keulen, C. J., van der Vorst, J. R., Vos, A. W. F., Vos, C. G., Vos, G. A., de Vos, B., Voûte, M. T., Vriens, B. H. R., Vriens, P. W. H. E., de Vries, D. K., de Vries, J. P. P. M., de Vries, M., de Vries, A. C., van der Waal, C., Waasdorp, E. J., Wallis de Vries, B. M., van Walraven, L. A., van Wanroi, J. L., Warlé, M. C., van Weel, V., van Well, A. M. E., Welten, G. M. J. M., Wever, J. J., Wiersema, A. M., Wikkeling, O. R. M., Willaert, W. I. M., Wille, J., Willems, M. C. M., Willigendael, E. M., Wilschut, E. D., Wisselink, W., Witte, M. E., Wittens, C. H. A., Wong, C. Y., Yazar, O., Yeung, K. K., Zeebregts, C. J. A. M., van Zeeland, M. L. P., ACS - Microcirculation, Anesthesiology, Physiology, ACS - Pulmonary hypertension & thrombosis, Surgery, ACS - Atherosclerosis & ischemic syndromes, VU University medical center, ACS - Diabetes & metabolism, TechMed Centre, Multi-Modality Medical Imaging, Medical Biochemistry, and AGEM - Amsterdam Gastroenterology Endocrinology Metabolism

Subjects
Male, Time Factors, Operative procedure, Vascular damage Radboud Institute for Health Sciences [Radboudumc 16], Risk Assessment, Blood Vessel Prosthesis Implantation, Postoperative Complications, Risk Factors, Humans, Hospital Mortality, Prospective Studies, Registries, Treatment outcome, Aged, Netherlands, Retrospective Studies, Aged, 80 and over, Endovascular Procedures, Quality of care, Middle Aged, Endovascular procedure, Abdominal aortic aneurysm, Surgery, Female, Trends, Cardiology and Cardiovascular Medicine, Aortic Aneurysm, Abdominal
Abstract

Contains fulltext : 251573.pdf (Publisher’s version ) (Open Access) OBJECTIVE: The Dutch Surgical Aneurysm Audit (DSAA) initiative was established in 2013 to monitor and improve nationwide outcomes of aortic aneurysm surgery. The objective of this study was to examine whether outcomes of surgery for intact abdominal aortic aneurysms (iAAA) have improved over time. METHODS: Patients who underwent primary repair of an iAAA by standard endovascular (EVAR) or open surgical repair (OSR) between 2014 and 2019 were selected from the DSAA for inclusion. The primary outcome was peri-operative mortality trend per year, stratified by OSR and EVAR. Secondary outcomes were trends per year in major complications, textbook outcome (TbO), and characteristics of treated patients. The trends per year were evaluated and reported in odds ratios per year. RESULTS: In this study, 11 624 patients (74.8%) underwent EVAR and 3 908 patients (25.2%) underwent OSR. For EVAR, after adjustment for confounding factors, there was no improvement in peri-operative mortality (aOR [adjusted odds ratio] 1.06, 95% CI 0.94 - 1.20), while major complications decreased (2014: 10.1%, 2019: 7.0%; aOR 0.91, 95% CI 0.88 - 0.95) and the TbO rate increased (2014: 68.1%, 2019: 80.9%; aOR 1.13, 95% CI 1.10 - 1.16). For OSR, the peri-operative mortality decreased (2014: 6.1%, 2019: 4.6%; aOR 0.89, 95% CI 0.82 - 0.98), as well as major complications (2014: 28.6%, 2019: 23.3%; aOR 0.95, 95% CI 0.91 - 0.99). Furthermore, the proportion of TbO increased (2014: 49.1%, 2019: 58.3%; aOR 1.05, 95% CI 1.01 - 1.10). In both the EVAR and OSR group, the proportion of patients with cardiac comorbidity increased. CONCLUSION: Since the establishment of this nationwide quality improvement initiative (DSAA), all outcomes of iAAA repair following EVAR and OSR have improved, except for peri-operative mortality following EVAR which remained unchanged.

Published
2022

11. A World without Mangroves?

Author

Duke, N. C., Meynecke, J.-O., Dittmann, S., Ellison, A. M., Anger, K., Berger, U., Cannicci, S., Diele, K., Ewel, K. C., Field, C. D., Koedam, N., Lee, S. Y., Marchand, C., Nordhaus, I., and Dahdouh-Guebas, F.

Published
2007

29. Stability, frequency and multiplicity of transposon insertions in the pyoverdine region in the chromosomes of different fluorescent pseudomonads

Author

Cornelis, P., Anjaiah, V., Koedam, N., Delfosse, P., Jacques, P., Thonart, P., and Neirinckx, L.

Subjects
Transposons -- Research, Mutagenesis -- Research, Pseudomonas -- Genetic aspects, Biological sciences
Abstract

Transposon mutagenesis in different fluorescent pseudomonads was studied. Pyoverdin negative (Pvd-) mutants were detected by their lack of fluorescence in iron-limited media and by their inability to grow in the presence of the iron chelator ethylenediamine di(o-hydroxyphenylacetic acid). It was shown that in P. aeruginosa, Tn5 and mini-Tn10 insertions are unstable and yield a high percentage of Pvd- mutants.

Published
1992

33. Modelling soil erosion potential in the transboundary (Kenya & Tanzania) catchment of river Umba using remotely sensed data

Author

Koedam, N., Mutisya, B., Kairo, J., Resink-Ndungu, Jane Njeri, and Kervyn, M.

Abstract

Soil erosion is one of the leading forms of soil degradation. Estimating soil erosion from field measurements is expensive hence the extent of soil erosion in many tropical watersheds is unknown. Erosion is a complex process; some of the eroded materials are deposited within the watershed while the rest is transported through waterways into lakes and lowland areas at the coast. The use of remotely sensed data and GIS provide a quick and reliable method to model, estimate, and monitor erosions over large areas even in data deficient tropical areas. In this study, Revised Universal Soil Loss Equation (RUSLE) model is being used to model soil erosion potential in a transboundary catchment of River Umba in Kenya and Tanzania. Data derived from MODIS (land cover), TRMM (rainfall), SRTM (elevation) and FAO (soil map) are processed in GIS environment for use in the model. Preliminary results, including; rainfall and run off erosivity (400 – 1700 MJ mm ha-1 h-1 yr-1), soil erodibility (0.018 – 0.025 t ha h ha-1 MJ-1 mm-1), slope length and steepness (0 – 1338), and vegetation cover factor (0.001 – 0.2) will be overlaid to predict the potential soil lost from the catchment annually. Results of this work will provide information on the extent of soil erosion in the catchment which has adverse effect on critical marine habitats. This information is key for policy makers and scientific community in making sound management decisions.Keywords: soil erosion; RUSLE; remote sensing; transboundary; critical habitats.

Published
2017

40. Are peri-urban mangroves vulnerable? An assessment through litter fall studies

Author

Mohamed, M.O.S., Mangion, P., Mwangi, S., Kairo, J.G., Dahdouh-Guebas, F., and Koedam, N.

Subjects
Phenology, Sewage, Climate, Vulnerability
Abstract

The productivity of an over-exploited and sewage polluted peri-urban mangrove was assessed through litter fall studies to establish vulnerability to human actions and climate change. Litter from three common mangrove species, Rhizophora mucronata Lam. (Rhizophoraceae), Sonneratia alba Sm. (Sonneratiaceae), and Avicennia marina (Forssk.) Vierh. (Avicenniaceae) were monitored over a period of two years. The mean annual litter fall was estimated at 12.16?±?2.89 t ha-1yr-1. Litter fall was seasonal in both content and quantity, with high rates occurring in the dry North Easterly Monsoon (NEM) season, January-April (ca. 5.10 ± 1.36 g DW m-2 day-1) and lower rates in the cool and wet South Easterly Monsoon (SEM) season, June-October (ca. 2.53 ± 0.47 g DW m-2 day-1). Litter fall varied significantly between species, R. mucronata recording the highest annual rate (15.34?±?3.34 t ha-1yr-1), with no significant difference between A. marina and S. alba, (11.44?±?2.90 and 9.69?±?5.26 t ha-1yr-1 respectively). Sewage exposure did not affect litter fall rates for all species, but affected leaf nutrient content as expressed by the leaf d15N signature. A strong correlation between leaf C:N ratio and leaf d15N signature was observed, indicating a more open N cycle, favouring d15N accumulation. Sewage exposure therefore does not necessarily translate into elevated productivity in mangroves, but causes alteration of leaf nutrient content depending on species. Prevailing climatic conditions however, may influence litter fall and thus phenology and health of the system. The vulnerability of the Tudor Creek mangroves to climate change may be ranked high due to low production (20%S. alba stand.

Published
2016

41. How are anatomical and hydraulic features of the mangroves Avicennia marina and Rhizophora mucronata influenced by siltation?

Author

De Deurwaerder, H., Okello, J.A., Koedam, N., Schmitz, N., and Steppe, K.

Abstract

Elevated sediment addition, or siltation, within mangrove ecosystems is considered as being negative for trees and saplings, resulting in stress and higher mortality rates. However, little is known about how siltation influences the hydraulic functioning of mangrove trees. Comparing two mangrove tree species (Avicennia marina Vierh. Forsk. and Rhizophora mucronata Lam.) from low and high-siltation plots led to the detection of anatomical and morphological differences and tendencies. Adaptations to high siltation were found to be either mutual among both species, e.g., significant smaller single leaf area (p A.marina = 0.058, F1.38 = 3.8; p R.mucronata = 0.005, F1.38 = 8.7; n = 20 × 20) and a tendency towards smaller stomatal areas (p A.marina = 0.131, F1.8 = 2.8; p R.mucronata = 0.185, F1.8 = 2.1, n = 5 × 60), or species-specific trends for A. marina, such as higher phloem band/growth layer ratios (p = 0.101, F1.8 = 3.4, n = 5 × 3) and stomatal density (p = 0.052, F1.8 = 5.2, n = 5 × 4). All adaptations seemingly contributed to a comparable hydraulic conductivity independent of the degree of siltation. These findings indicate that silted trees level off fluctuations in their hydraulic performance as a survival mechanism to cope with this less favourable environment. Most of the trees’ structural adaptations to cope with siltation are similar to known drought stress-imposed adaptations.

Published
2016

50. How to catch the patch? A dendrometer study of the radial increment through successive cambia in the mangrove Avicennia

Author

Robert, E.M.R., Jambia, A.H., Schmitz, N., De Ryck, D.J.R., De Mey, J., Kairo, J.G., Dahdouh-Guebas, F., Beeckman, H., and Koedam, N.

Subjects
Avicennia marina [grey mangrove]
Abstract

Background and Aims Successive vascular cambia are involved in the secondary growth of at least 200 woody species from >30 plant families. In the mangrove Avicennia these successive cambia are organized in patches, creating stems with non-concentric xylem tissue surrounded by internal phloem tissue. Little is known about radial growth and tree stem dynamics in trees with this type of anatomy. This study aims to (1) clarify the process of secondary growth of Avicennia trees by studying its patchiness; and (2) study the radial increment of Avicennia stems, both temporary and permanent, in relation to local climatic and environmental conditions. A test is made of the hypothesis that patchy radial growth and stem dynamics enable Avicennia trees to better survive conditions of extreme physiological drought. Methods Stem variations were monitored by automatic point dendrometers at four different positions around and along the stem of two Avicennia marina trees in the mangrove forest of Gazi Bay (Kenya) during 1 year. Key Results Patchiness was found in the radial growth and shrinkage and swelling patterns of Avicennia stems. It was, however, potentially rather than systematically present, i.e. stems reacted either concentrically or patchily to environment triggers, and it was fresh water availability and not tidal inundation that affected radial increment. Conclusions It is concluded that the ability to develop successive cambia in a patchy way enables Avicennia trees to adapt to changes in the prevailing environmental conditions, enhancing its survival in the highly dynamic mangrove environment. Limited water could be used in a more directive way, investing all the attainable resources in only some locations of the tree stem so that at least at these locations there is enough water to, for example, overcome vessel embolisms or create new cells. As these locations change with time, the overall functioning of the tree can be maintained.

Published
2014

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