Papers by Paul Erftemeijer
Variability in transport of fish eggs and larvae. I. Modelling the effects of coastal reclamation
Marine Ecology Progress Series, 2009
Year-class strength in plaice appears to be deter-mined during the pelagic egg and larval stages,... more Year-class strength in plaice appears to be deter-mined during the pelagic egg and larval stages, but the processes that generate recruitment variability are not fully understood. Relative year-class strength is set by the time the metamorphosing larvae reach the coastal ...
5.3. Seagrass Ecosystems of Papua
The ecology of Papua, 2007
... of this region but it would be safe to assume that of the nine factors, human impacts, propag... more ... of this region but it would be safe to assume that of the nine factors, human impacts, propagule availability, and climate change would have ... The Raja Ampat Archipelago includes the four large islands of Waigeo, Batanta, Salawati, and Misool and hundreds of smaller islands. ...
Biological Conservation, 2011
Seagrasses, a functional group of marine flowering plants rooted in the world's coastal oceans, s... more Seagrasses, a functional group of marine flowering plants rooted in the world's coastal oceans, support marine food webs and provide essential habitat for many coastal species, playing a critical role in the equilibrium of coastal ecosystems and human livelihoods. For the first time, the probability of extinction is determined for the world's seagrass species under the Categories and Criteria of the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. Several studies have indicated that seagrass habitat is declining worldwide. Our focus is to determine the risk of extinction for individual seagrass species, a 4-year process involving seagrass experts internationally, compilation of data on species' status, populations, and distribution, and review of the biology and ecology of each of the world's seagrass species. Ten seagrass species are at elevated risk of extinction (14% of all seagrass 0006-3207/$ -see front matter Ó Threatened Endangered Biodiversity species), with three species qualifying as Endangered. Seagrass species loss and degradation of seagrass biodiversity will have serious repercussions for marine biodiversity and the human populations that depend upon the resources and ecosystem services that seagrasses provide.
Environmental Research Letters, 2012
Global seagrass habitats are threatened by multiple anthropogenic factors. Effective management o... more Global seagrass habitats are threatened by multiple anthropogenic factors. Effective management of seagrasses requires information on the relative impacts of threats; however, this information is rarely available. Our goal was to use the knowledge of experts to assess the relative impacts of anthropogenic activities in six global seagrass bioregions. The activities that threaten seagrasses were identified at an international seagrass workshop and followed with a web-based survey to collect seagrass vulnerability information. There was a global consensus that urban/industrial runoff, urban/port infrastructure development, agricultural runoff and dredging had the greatest impact on seagrasses, though the order of relative impacts varied by bioregion. These activities are largely terrestrially based, highlighting the need for marine planning initiatives to be co-ordinated with adjacent watershed planning. Sea level rise and increases in the severity of cyclones were ranked highest relative to other climate change related activities, but overall the five climate change activities were ranked low and experts were uncertain of their effects on seagrasses. The experts' preferred mechanism of delivering management outcomes were processes such as policy development, planning and consultation rather than prescriptive management tools. Our approach to collecting expert opinion provides the required data to prioritize seagrass management actions at bioregional scales.
SEAGRASSES: BIOLOGY, ECOLOGYAND CONSERVATION, 2006
Biological Conservation, 2011
Seagrasses, a functional group of marine flowering plants rooted in the world's coastal oceans, s... more Seagrasses, a functional group of marine flowering plants rooted in the world's coastal oceans, support marine food webs and provide essential habitat for many coastal species, playing a critical role in the equilibrium of coastal ecosystems and human livelihoods. For the first time, the probability of extinction is determined for the world's seagrass species under the Categories and Criteria of the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. Several studies have indicated that seagrass habitat is declining worldwide. Our focus is to determine the risk of extinction for individual seagrass species, a 4-year process involving seagrass experts internationally, compilation of data on species' status, populations, and distribution, and review of the biology and ecology of each of the world's seagrass species. Ten seagrass species are at elevated risk of extinction (14% of all seagrass 0006-3207/$ -see front matter Ó Threatened Endangered Biodiversity species), with three species qualifying as Endangered. Seagrass species loss and degradation of seagrass biodiversity will have serious repercussions for marine biodiversity and the human populations that depend upon the resources and ecosystem services that seagrasses provide.
SEAGRASSES: BIOLOGY, ECOLOGYAND CONSERVATION, 2006
Aquatic Botany, 1999
Monospecific meadows of Halophila ovalis (R. Brown) Hooker f. were studied in deep waters (14-16 ... more Monospecific meadows of Halophila ovalis (R. Brown) Hooker f. were studied in deep waters (14-16 m) around Langkai island in South Sulawesi, Indonesia, during May-September 1990. The average shoot density of Halophila in biomass samples (n=10) taken from these meadows was 1099 ± 195 leaf pairs m −2 . Comparison with average leaf pair densities (427 ± 211 leaf pairs m −2 ) estimated by in situ counts under water (using SCUBA) revealed that more than 50% of the leaf tissue was covered under the sediment. The leaf area index (LAI) was 0.68 ± 0.32 m 2 m −2 (including sediment-covered leaves). Total seagrass biomass in the meadows averaged 10.93 ± 2.65 g ADW m −2 , of which 42% was contributed by above-ground plant parts. Metabolic measurements using the bell jar technique and plastochron interval measurements gave comparable results, revealing total plant production to range between 0.83 and 1.38 g C m −2 day −1 with a turn-over of total plant biomass of 3.9-6.6 days. Rhizome tagging experiments showed that 34% of this production may be contributed by the below-ground biomass. The light compensation point for Halophila ovalis at 15 m depth was 33 mol photons m −2 s −1 . The high primary production of these sparsely grown meadows at such considerable depths (14-16 m) and under high stress from sedimentation (at the bottom of a reef slope) is attributed to the strongly opportunistic character of this seagrass species, whose meadows can be found to depths of over 30 m in the study area. (P.L.A. Erftemeijer) 0304-3770/99/$ -see front matter ©1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 0 4 -3 7 7 0 ( 9 9 ) 0 0 0 3 2 -7
Over the past few decades, various indicator sets have been developed in the Netherlands to measu... more Over the past few decades, various indicator sets have been developed in the Netherlands to measure North Sea 'ecological quality', to evaluate the effectiveness of North Sea nature and water policies, and to assist in the communication of predicted ecological impacts of major infrastructural works and other proposed developments in the North Sea. This research study focused on the development
Journal of Experimental Marine Biology and Ecology, 1994
Seagrass response to in situ sediment nutrient enrichment with slow-release fertilizers was studi... more Seagrass response to in situ sediment nutrient enrichment with slow-release fertilizers was studied (4 to 5 months after fertilization) in three tropical seagrass beds in South Sulawesi, Indonesia. Nitrogen-addition and P-addition had no significant effects on seagrass biomass, shoot density, and leaf production in mixed seagrass beds in a terrigenous sandy bay and a carbonate sedimentary reef flat environment, simultaneously fertilized in 1990. An additional experiment using a slightly adapted methodology (1991) at another carbonate site, characterized by a more homogeneously vegetated, and largely monospecitic * Corresponding author.
A concise review of the impacts of dredging and disposal of dredged material on seagrasses is pre... more A concise review of the impacts of dredging and disposal of dredged material on seagrasses is presented, with a special emphasis on the Mediterranean Sea. The critical thresholds of seagrasses for turbidity and sedimentation are discussed, along with four case studies of dredging impacts on seagrasses in the Mediterranean Sea (accounting for the loss of an estimated 1,450 ha). The paper concludes with an overview of mitigating measures and management options (including site-specific dredging criteria) that can be applied to control and minimise the impacts of dredging on seagrasses in the Mediterranean.
Diatoms as Epiphytes on Seagrasses in South Sulawesi (Indonesia) Comparison with Growth on Inert Substrata
Botanica Marina, 1995
Page 1. Botanica Marina Vol. 38, 1995, pp. 1 -7 © 1995 by Walter de Gruyter · Berlin · New York D... more Page 1. Botanica Marina Vol. 38, 1995, pp. 1 -7 © 1995 by Walter de Gruyter · Berlin · New York Diatoms as Epiphytes on Seagrasses in South Sulawesi (Indonesia) Comparison with Growth on Inert Substrata FAS Sterrenburg*'*'1, PLA Erftemeijera'b and PH Nienhuisb'c ...
South African Journal of Botany, 2001
A bibliometric review was made of published and grey literature on marine botanical research in t... more A bibliometric review was made of published and grey literature on marine botanical research in the Western Indian Ocean (1950-2000) to evaluate the current status of marine botanical research in the East African region. All literature references indexed in Aquatic Sciences and Fisheries Abstracts, Life Sciences Collection, and other computerised databases, as well as annual reports, bibliographies, web-sites, review articles, cross-references, papers and reports published in grey literature -obtained from various institutions and libraries operating in this region -were systematically analysed to provide a diagnosis of strengths and weaknesses in the marine botanical research in the region to date. The results of the analysis are discussed in order to identify the main challenges to be faced as a solid basis for future research efforts in marine botany in the East African region.
The macrobenthic fauna of two intertidal habitats in Bintuni Bay, Irian jaya (Indonesia) was brie... more The macrobenthic fauna of two intertidal habitats in Bintuni Bay, Irian jaya (Indonesia) was briefly studied by coring. Sand-dominated flats had a low biomass value of 2.6 g ash-free dry weight per m2, dominated by bivalves. Soft muddy substrates had a higher biomass value of 10.4 g ash-free dry weight per m2, dominated by crustaceans. The gut contents of 28 selected fish species from the bay indicated the importance of macrobenthic fauna as a major food source for a large part of the bay’s ichthyofauna.
Wetlands, 2013
We present an eco-morphodynamic analysis on causes of erosion along degraded mangrove-mud coasts,... more We present an eco-morphodynamic analysis on causes of erosion along degraded mangrove-mud coasts, and the causes of failure to rehabilitate these coasts. Our analyses are based on studies in Thailand, British Guyana and Suriname, and observations in Indonesia, the Philippines and southern China, where degradation is directly attributed to the erection of fish/shrimp ponds too close to the waterline. Ecological determinants of low success rates of rehabilitation efforts are well explained in literature, and are briefly summarized in this paper. Our analyses show that ongoing erosion of degraded mangrove-mud coasts are also the result of a disturbed balance in fine sediment dynamics, and the subsequent change in mudflat morphology. The initial drivers for this degradation are a decrease in on-shore sediment flux and a local increase in wave height near the fish/shrimp ponds. A positive feed-back loop is initiated by which stable, convex-up cross sectional profiles of mud flats evolve towards unstable, concave-up profiles. This loop is induced by an unfavorable feedback between tide-induced sedimentation and wave-induced erosion, deteriorating habitat conditions for mangrove recruitment. Based on the current analysis, we present ingredients for a more sustainable use of mangrove-mud coastal systems, and a more successful rehabilitation of eroding mangrove-mud coasts.
Suppl. files Gittenberger et al. 2014 (Aquatic Conservation) - Coral reef organisms as bioregion indicators off Halmahera
PLoS ONE, 2014
Sediment loads have long been known to be deleterious to corals, but the effects of turbidity and... more Sediment loads have long been known to be deleterious to corals, but the effects of turbidity and settling particles have not previously been partitioned. This study provides a novel approach using inert silicon carbide powder to partition and quantify the mechanical effects of sediment settling versus reduced light under a chronically high sedimentary regime on two turbid water corals commonly found in Singapore (Galaxea fascicularis and Goniopora somaliensis). Coral fragments were evenly distributed among three treatments: an open control (30% ambient PAR), a shaded control (15% ambient PAR) and sediment treatment (15% ambient PAR; 26.4 mg cm 22 day 21 ). The rate of photosynthesis and respiration, and the dark-adapted quantum yield were measured once a week for four weeks. By week four, the photosynthesis to respiration ratio (P/R ratio) and the photosynthetic yield (F v /F m ) had fallen by 14% and 3-17% respectively in the shaded control, contrasting with corals exposed to sediments whose P/R ratio and yield had declined by 21% and 18-34% respectively. The differences in rates between the shaded control and the sediment treatment were attributed to the mechanical effects of sediment deposition. The physiological response to sediment stress differed between species with G. fascicularis experiencing a greater decline in the net photosynthetic yield (13%) than G. somaliensis (9.5%), but a smaller increase in the respiration rates (G. fascicularis = 9.9%, G. somaliensis = 14.2%). These different physiological responses were attributed, in part, to coral morphology and highlighted key physiological processes that drive species distribution along high to low turbidity and depositional gradients.
Sediment and Ecology: how to minimize impacts of dredging and create opportunities for restoration on tropical coasts?
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Papers by Paul Erftemeijer