Papers by Marcel Middeljans
Biodiversitas Journal of Biological Diversity
Shrimp farming in Demak, Indonesia is often practiced in silvo-aquaculture systems in which mangr... more Shrimp farming in Demak, Indonesia is often practiced in silvo-aquaculture systems in which mangrove trees are planted on pond bunds. As such, mangrove leaves and its substrates may have impact on penaeid shrimp production. In this area, mangrove regrowth proceeded with Avicennia marina while planting is mostly done with Rhizophora apiculata. We compared the effects of decomposing fresh leaves of A. marina and R. apiculata on water quality and on the performance of Penaeus monodon postlarvae (PL). A hundred of PL21 (postlarvae aged 21 days with weight of 0.28 g) were stocked in each of 30 aerated tanks containing 800 liters of brackish water (salinity of 21 ppt) for 37 days. Five treatments with three replicates for each mangrove species were assigned by adding into the tanks of 0.125, 0.25, and 0.5 g L-1 of air-dried leave, 0.125 of g L-1 minced leave and 0.125 g L-1 of leachate of minced leaves. The PLs were fed 3 times daily with pellets at 10 % of initial total body weight. Water quality parameters were recorded daily. Tannin, H2S and NH3-N concentrations were measured every ten days. Prawn's body weight (BW) was measured and specific growth rate (SGR, % day-1) and survival rate (SR, %) were calculated after the end of experiment. Results were analyzed with ANOVA and Pearson's correlation. The results showed that tannin in decomposing mangrove leaf litter up to a concentration of 0.5 mg g-1 did not have a significant effect on water quality and on the growth and survival of P. monodon PL. However, increasing leaf litter concentrations showed an increase in NH3-N concentration due to organic matter degradation. The accumulation of NH3-N may have caused the slow growth of shrimp PL in A. marina treatment. Shrimp PL in leaf litter leachates treatment has a higher growth rate than those PL in regular leaf litter in relation to nutritional value. Survival and growth varied from 62 ±14 to 70 ± 8% and 3.1±2.1 to 5.5±1.2% day-1 , respectively. Although decomposing mangrove leaves of A. marina and R. apiculata had no toxic effects on P. monodon PL up to a concentration of 1.25 g L-1 , but causing severe mortality for shrimp in tanks without water exchange. As a conclusion, the present of mangrove leaves in brackish water ponds with insufficient water exchange can be harmful to shrimps. However, if the water exchange is good, decomposed mangrove leaves can become organic fertilizer that beneficial for the growth of natural food for the shrimps
The species composition, diversity, population structure and natural regeneration status of mangr... more The species composition, diversity, population structure and natural regeneration status of mangroves
in managed and unmanaged Nipa (Nypa fruticans Wurmb) were studied along the Abatan River in
Lincod, Maribojoc, Philippines with the purpose of evaluating the effects of Nipa management on the
mangrove forest health. This study was carried out as part of a project by PROCESS-Bohol, Inc. entitled,
‘’Re-assessment of Community-Managed Mangrove Forest Ecosystems in Maribojoc Bay”. A total of
56 plots with an area of 100 m² were sampled and evaluated for trees and 112 subplots of 25 m² for
Nipa palm and juveniles. A total of 295 individual mangrove trees, 167 saplings and 1,588 seedlings
belonging to 21 tree species were recorded in the 105 ha mixed mangrove forest. A total of 29 true
mangrove species and 18 mangrove associates were recorded in the villages of Lincod and Cabawan,
of which the globally endangered Camptostemon philippinense. Including two additional species,
which were found in the village of Upper dela Paz, makes the total number of identified mangrove
species along the Abatan River: 31. The overall mangrove forest in Lincod had a total density of 527
stems ha¯̄¹; total basal area of 17.16 m² ha¯̄¹; average DBH of 13.4 cm; average height of 11 m; and
species diversity (H’) of 1.93. Next to the dense and gregarious Nipa palm (15,000 palms ha¯̄¹), the
species composition was dominated by Sonneratia alba with a density of 180 stems ha¯̄¹ and an
importance value (IV) of 103.23. Unmanaged Nipa was significally more dense (61,800 fronds ha¯̄¹)
compared to managed Nipa (45,500 fronds ha¯̄¹). Although all mangrove trees formed together a
reverse-J-shaped diameter distribution in both managed and unmanaged Nipa area, mangroves in
managed Nipa were considered healthier with good condition and more adequate mangrove
regeneration, while unmanaged Nipa had a higher structural development. Besides, the value of
mangrove tree species diversity in managed Nipa was more diverse with Shannon-Wiener (H’ = 2.203)
as compared to unmanaged Nipa which had a lower value (H’ = 1.693).
Clients: PROCESS-Bohol, Inc. and ALIMANGO 2 The species composition of the mangrove forest along ... more Clients: PROCESS-Bohol, Inc. and ALIMANGO 2 The species composition of the mangrove forest along the Abatan River in Lincod, Maribojoc, Bohol, Philippines and the mangrove forest structure and its regeneration status between managed and unmanaged Nipa palm (Nypa fruticans Wurmb)
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Papers by Marcel Middeljans
in managed and unmanaged Nipa (Nypa fruticans Wurmb) were studied along the Abatan River in
Lincod, Maribojoc, Philippines with the purpose of evaluating the effects of Nipa management on the
mangrove forest health. This study was carried out as part of a project by PROCESS-Bohol, Inc. entitled,
‘’Re-assessment of Community-Managed Mangrove Forest Ecosystems in Maribojoc Bay”. A total of
56 plots with an area of 100 m² were sampled and evaluated for trees and 112 subplots of 25 m² for
Nipa palm and juveniles. A total of 295 individual mangrove trees, 167 saplings and 1,588 seedlings
belonging to 21 tree species were recorded in the 105 ha mixed mangrove forest. A total of 29 true
mangrove species and 18 mangrove associates were recorded in the villages of Lincod and Cabawan,
of which the globally endangered Camptostemon philippinense. Including two additional species,
which were found in the village of Upper dela Paz, makes the total number of identified mangrove
species along the Abatan River: 31. The overall mangrove forest in Lincod had a total density of 527
stems ha¯̄¹; total basal area of 17.16 m² ha¯̄¹; average DBH of 13.4 cm; average height of 11 m; and
species diversity (H’) of 1.93. Next to the dense and gregarious Nipa palm (15,000 palms ha¯̄¹), the
species composition was dominated by Sonneratia alba with a density of 180 stems ha¯̄¹ and an
importance value (IV) of 103.23. Unmanaged Nipa was significally more dense (61,800 fronds ha¯̄¹)
compared to managed Nipa (45,500 fronds ha¯̄¹). Although all mangrove trees formed together a
reverse-J-shaped diameter distribution in both managed and unmanaged Nipa area, mangroves in
managed Nipa were considered healthier with good condition and more adequate mangrove
regeneration, while unmanaged Nipa had a higher structural development. Besides, the value of
mangrove tree species diversity in managed Nipa was more diverse with Shannon-Wiener (H’ = 2.203)
as compared to unmanaged Nipa which had a lower value (H’ = 1.693).
in managed and unmanaged Nipa (Nypa fruticans Wurmb) were studied along the Abatan River in
Lincod, Maribojoc, Philippines with the purpose of evaluating the effects of Nipa management on the
mangrove forest health. This study was carried out as part of a project by PROCESS-Bohol, Inc. entitled,
‘’Re-assessment of Community-Managed Mangrove Forest Ecosystems in Maribojoc Bay”. A total of
56 plots with an area of 100 m² were sampled and evaluated for trees and 112 subplots of 25 m² for
Nipa palm and juveniles. A total of 295 individual mangrove trees, 167 saplings and 1,588 seedlings
belonging to 21 tree species were recorded in the 105 ha mixed mangrove forest. A total of 29 true
mangrove species and 18 mangrove associates were recorded in the villages of Lincod and Cabawan,
of which the globally endangered Camptostemon philippinense. Including two additional species,
which were found in the village of Upper dela Paz, makes the total number of identified mangrove
species along the Abatan River: 31. The overall mangrove forest in Lincod had a total density of 527
stems ha¯̄¹; total basal area of 17.16 m² ha¯̄¹; average DBH of 13.4 cm; average height of 11 m; and
species diversity (H’) of 1.93. Next to the dense and gregarious Nipa palm (15,000 palms ha¯̄¹), the
species composition was dominated by Sonneratia alba with a density of 180 stems ha¯̄¹ and an
importance value (IV) of 103.23. Unmanaged Nipa was significally more dense (61,800 fronds ha¯̄¹)
compared to managed Nipa (45,500 fronds ha¯̄¹). Although all mangrove trees formed together a
reverse-J-shaped diameter distribution in both managed and unmanaged Nipa area, mangroves in
managed Nipa were considered healthier with good condition and more adequate mangrove
regeneration, while unmanaged Nipa had a higher structural development. Besides, the value of
mangrove tree species diversity in managed Nipa was more diverse with Shannon-Wiener (H’ = 2.203)
as compared to unmanaged Nipa which had a lower value (H’ = 1.693).