Keragaman dan Komposisi Jenis Tumbuhan Sebagai Bioindikator Pemulihan Lahan Gambut di Kalimantan Tengah Setelah Terbakar

AbstrakDegradasi hutan menyebabkan perubahan komposisi jenis penyusun tegakan. Penelitian ini bertujuan memperoleh gambaran kemampuan regenerasi alami dari areal bekas terbakar berdasarkan parameter keragaman jenis dan menggambarkan proses regenerasi alami pada areal bekas terbakar. Survei untuk memperoleh data jumlah dan kerapatan jenis, keragaman, dan komposisi jenis penyusun tegakan pada tiga lokasi yakni areal hutan sekunder, bekas terbakar 1997, dan bekas terbakar 2015. Penentuan keragaman jenis tersebut menggunakan beberapa indeks ekologi. Hasil penelitian menunjukkan bahwa komposisi jenis penyusun tegakan bervariasi antar lokasi. Pada areal bekas terbakar 2015, jumlah dan komposisi jenis penyusun tegakannya paling rendah, sedangkan pada areal bekas terbakar 1997 dan hutan sekunder mempunyai jumlah dan komposisi jenis yang hampir mirip. Perubahan komposisi jenis terbesar terjadi pada areal bekas terbakar 2015 dengan pengurangan jenis >82% untuk seluruh tingkat permudaan. Berdasarkan indeks ekologinya, areal hutan sekunder mempunyai tingkat kemerataan yang tinggi, tidak didominasi oleh jenis tertentu, dan jenis lebih beragam. Namun demikian, indeks ekologi pada areal bekas terbakar 1997 mendekati nilai dari hutan sekunder. Kondisi ini berdasarkan indeks kesamaan komunitas yang tinggi pada tingkat semai dan pancang >50%. Hal ini menunjukkan pemulihan alami pada areal bekas terbakar 1997 sangat mungkin terjadi dan areal bekas terbakar 2015 membutuhkan intervensi untuk meningkatkan kemampuan pemulihannya.AbstractThe forest degradation has altered stand composition. The research objectives was to obtain natural regeneration ability of post burning area based on species diversity parameter and describing the process of natural regeneration on the burnt area. The survey was carried out to obtain the data of number and species density, diversity and species composition of three stands including secondary forest, arean burnt in 1997 and 2015. Species diversity was measured with several ecological index. The result showed that species composition varied between those areas. The lowest stand species compositon was the 2015 burnt area. The 1997 burnt area and the secondary forest were similar in terms of stand species composition. The biggest changes of species composition was the 2015 burnt area with species removal of more than 82% for all regeneration stages. Based on the ecological indexes, the secondary forest had the highest evenness, no domination of a certain species and more diverse species existed. Nevertheless, ecological index of area burnt in 1997 was resembling the value of secondary forest. This condition was shown by the community similarity index of seedlings and saplings of  >50%. It indicated that the natural regeneration of the 1997 burnt area was happening and intervention was needed for the 2015 burnt area

Keanekaragaman Potensi Regenerasi Vegetasi pada Hutan Rawa Gambut: Studi Kasus di Kawasan Hutan Dengan Tujuan Khusus (KHDTK) Tumbang Nusa, Kalimantan Tengah

Degradasi ekosistem hutan termasuk hutan rawa gambut umumnya diwakili oleh degradasi tutupan vegetasi. Degradasi hutan cenderung mengikuti gradien jarak dari tepi hutan menuju ke dalam hutan. Tujuan dari penelitian adalah untuk mengetahui keanekaragaman dan dominasi potensi regenerasi alami di hutan rawa gambut di Kalimantan Tengah. Anakan alam, guguran buah, dan biji yang tersimpan di lapisan tanah sebagai indikator potensi regenerasi alami diukur dari serangkaian plot terletak mengikuti gradien jarak. Hasil penelitian menunjukkan perbedaan potensi regenerasi alami mengikuti gradien jarak secara signifikan. Keragaman potensi regenerasi alami cenderung menurun mengikuti gradien gangguan, di mana yang terendah ditemukan di tepi hutan. Anakan alam di tepi didominasi oleh Combretocarpus rotundatus (Miq.) Danser sementara Litsea oppositifolia L.S. Gibbs mendominasi di bagian dalam. Guguran buah didominasi oleh Combretocarpus rotundatus di semua gradien jarak pada musim kemarau, sementara itu Palaquium sp. mendominasi gradien dalam hutan dan Combretocarpus rotundatus mendominasi gradien tepi hutan selama musim pancaroba. Hal ini menunjukkan bahwa musim memberi efek signifikan pada jumlah biji, jumlah spesies, dan keanekaragaman guguran buah, dan ketiga indikator potensi regenerasi ternyata lebih tinggi selama musim pancaroba. Biji di lapisan tanah didominasi oleh Tristaniopsis obovata (Benn.) Peter G. Wilson & J.T. Waterh di gradien dalam hutan dan Diospyros sp. di gradien tepi. Namun, biji di lapisan tanah di gradien tepi ini merupakan jenis yang menyusun pada gradien dalam hutan (50% indeks kesamaan). Hal ini menunjukkan bahwa penyebaran benih dari hutan sebagai sumber inokulum masih bisa mencapai tepi dan juga menunjukkan bagaimana kehadiran vegetasi di gradien tepi sebelum terjadi gangguan.Kata kunci: anakan alam; biji di lapisan tanah; gradien jarak; guguran buah; hutan rawa gambut Potential Diversity of Natural Regeneration in Peat Swamp Forest: A Case Study at Forest for Specific Purpose (KHDTK) Tumbang Nusa, Central KalimantanAbstractDegradation of forest ecosystem including peat swamp forest is generally represented by the degradation of its vegetation cover. Forest degradation tends to follow edge-to-interior distance gradient. This study aimed to determine the diversity and dominance of natural regeneration potential in peat swamp forest at Central Kalimantan. Seedling bank, seed rain, and seed soil bank as the indicators of natural regeneration potential were measured from series of plots located following the distance gradient. The results showed that the difference in natural regeneration potentials followed the distance gradient significantly. The diversity of natural regeneration potential tends to decrease following disturbance gradient, where the lowest was found near the edge. Seedling bank at the edge was dominated by Combretocarpus rotundatus (Miq.) Danser while Litsea oppositifolia L.S. Gibbs dominated at the interior. The seed rain was dominated by Combretocarpus rotundatus at all sites during dry season while during intermediate season, Palaquium sp. dominated the interior and Combretocarpus rotundatus near the edge. It was showed that climatic season gave significant effects on seed number, species number, and diversity of seed rain in which all the three regeneration indications were higher during intermediate season. The seed soil bank was dominated by Tristaniopsis obovata (Benn.) Peter G. Wilson & J.T. Waterh near to the interior and by Diospyros sp. at the edge. However, seed soil banks at the edge zone were dominated by species composing the interior forest (50% similarity index). This shows that the seed dispersal from forest as inoculum source can still reach the edge and also indicates existing vegetation at the edge prior to disturbance

Land use change alters carbon composition and degree of decomposition of tropical peat soils

Drainage associated with land use change in tropical peatlands has increased the rate of decomposition of peat soils and contributed to CO2 emissions. Increased decomposition may result in changes in the composition of the soil organic carbon (SOC). We examined the carbon functional group composition and degree of decomposition of peat soils under five different land uses to understand the effects of changing management intensity on tropical peatland soils. Samples were collected from seven sites spanning five different land uses (forest, shrubland, fernland, revegetation, smallholder oil palm) at the Pedamaran peatland in South Sumatra, Indonesia. SOC composition, measured by Solid-state 13C Nuclear Magnetic Resonance (NMR) spectroscopy, was dominated by the alkyl carbon (C) functional group in managed peatlands. However, in the forest far from drainage canals, the SOC comprised predominantly O-alkyl C. The contributions of the functional groups ketone C, carbonyl C and O-aryl C were low and tended to occur in stable proportions throughout the soil profiles. Drainage and land use change significantly affected peat carbon chemistry. The effects were greatest under oil palm, where O-alkyl C had been depleted rapidly under aerobic conditions leading to a change in the dominant carbon functional group from O-alkyl C to alkyl C. Furthermore, our results indicate that the alkyl C:O-alkyl C ratio is a more useful and informative indicator of the degree of decomposition of peat soil than the traditionally used C:N ratio. This more nuanced understanding of the different types of carbon that make up tropical peat soils under different land uses can be applied to support peatland restoration. In particular, nutrient cycling and water availability are likely to be influenced by carbon functional group and degree of decomposition. In order to reduce fire risk and support Indonesia’s aspirations to manage the national forest estate as a net carbon sink, further research into the links between peat soil organic carbon chemistry, revegetation performance and new peat accumulation is recommended

Tree species that 'live slow, die older' enhance tropical peat swamp restoration : Evidence from a systematic review

Degraded tropical peatlands lack tree cover and are often subject to seasonal flooding and repeated burning. These harsh environments for tree seedlings to survive and grow are therefore challenging to revegetate. Knowledge on species performance from previous plantings represents an important evidence base to help guide future tropical peat swamp forest (TPSF) restoration efforts. We conducted a systematic review of the survival and growth of tree species planted in degraded peatlands across Southeast Asia to examine (1) species differences, (2) the impact of seedling and site treatments on survival and growth and (3) the potential use of plant functional traits to predict seedling survival and growth rates. Planted seedling monitoring data were compiled through a systematic review of journal articles, conference proceedings, reports, theses and unpublished datasets. In total, 94 study-sites were included, spanning three decades from 1988 to 2019, and including 141 indigenous peatland tree and palm species. Accounting for variable planting numbers and monitoring durations, we analysed three measures of survival and growth: (1) final survival weighted by the number of seedlings planted, (2) half-life, that is, duration until 50% mortality and (3) relative growth rates (RGR) corrected for initial planting height of seedlings. Average final survival was 62% and half-life was 33 months across all species, sites and treatments. Species differed significantly in survival and half-life. Seedling and site treatments had small effects with the strongest being higher survival of mycorrhizal fungi inoculated seedlings; lower survival, half-life and RGR when shading seedlings; and lower RGR and higher survival when fertilising seedlings. Leaf nutrient and wood density traits predicted TPSF species survival, but not half-life and RGR. RGR and half-life were negatively correlated, meaning that slower growing species survived for longer. Synthesis and applications. To advance tropical peat swamp reforestation requires expanding the number and replication of species planted and testing treatments by adopting control vs. treatment experimental designs. Species selection should involve slower growing species (e.g. Lophopetalum rigidum, Alstonia spatulata, Madhuca motleyana) that survive for longer and explore screening species based on functional traits associated with nutrient acquisition, flooding tolerance and recovery from fire.Peer reviewe

Tree species that 'live slow, die older' enhance tropical peat swamp restoration : Evidence from a systematic review

Degraded tropical peatlands lack tree cover and are often subject to seasonal flooding and repeated burning. These harsh environments for tree seedlings to survive and grow are therefore challenging to revegetate. Knowledge on species performance from previous plantings represents an important evidence base to help guide future tropical peat swamp forest (TPSF) restoration efforts. We conducted a systematic review of the survival and growth of tree species planted in degraded peatlands across Southeast Asia to examine (1) species differences, (2) the impact of seedling and site treatments on survival and growth and (3) the potential use of plant functional traits to predict seedling survival and growth rates. Planted seedling monitoring data were compiled through a systematic review of journal articles, conference proceedings, reports, theses and unpublished datasets. In total, 94 study-sites were included, spanning three decades from 1988 to 2019, and including 141 indigenous peatland tree and palm species. Accounting for variable planting numbers and monitoring durations, we analysed three measures of survival and growth: (1) final survival weighted by the number of seedlings planted, (2) half-life, that is, duration until 50% mortality and (3) relative growth rates (RGR) corrected for initial planting height of seedlings. Average final survival was 62% and half-life was 33 months across all species, sites and treatments. Species differed significantly in survival and half-life. Seedling and site treatments had small effects with the strongest being higher survival of mycorrhizal fungi inoculated seedlings; lower survival, half-life and RGR when shading seedlings; and lower RGR and higher survival when fertilising seedlings. Leaf nutrient and wood density traits predicted TPSF species survival, but not half-life and RGR. RGR and half-life were negatively correlated, meaning that slower growing species survived for longer. Synthesis and applications. To advance tropical peat swamp reforestation requires expanding the number and replication of species planted and testing treatments by adopting control vs. treatment experimental designs. Species selection should involve slower growing species (e.g. Lophopetalum rigidum, Alstonia spatulata, Madhuca motleyana) that survive for longer and explore screening species based on functional traits associated with nutrient acquisition, flooding tolerance and recovery from fire.Peer reviewe

Response of tropical peat swamp forest tree species seedlings to macro nutrients

Abstract Efforts of restoration of degraded tropical peat swamp forest were facing constraints due to the low available nutrient level of peat. The transplanted peat swamp forest species seedlings experienced low survival rate and poor growth performance. This study aimed to demonstrate the response of ten tropical peat swamp forest species seedlings whether climax and pioneer species to macro-nutrients addition in the nursery. The growth performance of climax and pioneer tropical peat swamp species seedlings was recorded following addition of macro nutrients of Nitrogen (N), Phosphorus(P), Potassium(K) and Dolomitic limestone (CaMg). The result showed that Alstonia spatulata and Parartocarpus venenosus showed positive growth response following macro nutrients addition. This study concluded that tropical peat swamp pioneer species has lower necessity for macro-nutrients addition than tropical peat swamp climax species

Keanekaragaman Potensi Regenerasi Vegetasi pada Hutan Rawa Gambut: Studi Kasus di Kawasan Hutan Dengan Tujuan Khusus (KHDTK) Tumbang Nusa, Kalimantan Tengah

Degradation of forest ecosystem including peat swamp forest is generally represented by the degradation of its vegetation cover. Forest degradation tends to follow edge-to-interior distance gradient. This study aimed to determine the diversity and dominance of natural regeneration potential in peat swamp forest at Central Kalimantan. Seedling bank, seed rain, and seed soil bank as the indicators of natural regeneration potential were measured from series of plots located following the distance gradient. The results showed that the difference in natural regeneration potentials followed the distance gradient significantly. The diversity of natural regeneration potential tends to decrease following disturbance gradient, where the lowest was found near the edge. Seedling bank at the edge was dominated by Combretocarpus rotundatus (Miq.) Danser while Litsea oppositifolia L.S. Gibbs dominated at the interior. The seed rain was dominated by Combretocarpus rotundatus at all sites during dry season while during intermediate season, Palaquium sp. dominated the interior and Combretocarpus rotundatus near the edge. It was showed that climatic season gave significant effects on seed number, species number, and diversity of seed rain in which all the three regeneration indications were higher during intermediate season. The seed soil bank was dominated by Tristaniopsis obovata (Benn.) Peter G. Wilson & J.T. Waterh near to the interior and by Diospyros sp. at the edge. However, seed soil banks at the edge zone were dominated by species composing the interior forest (50% similarity index). This shows that the seed dispersal from forest as inoculum source can still reach the edge and also indicates existing vegetation at the edge prior to disturbance

Three Years Post Fire Areas Natural Regeneration of Peat Swamp Forest in Merang, Musi Banyuasin District, South Sumatera

This study examines natural regeneration of tropical peat swamp forest after fire. The study area is located in Merang Peat Swamp Forest (PSF) in Musi Banyuasin District. Merang PSF is situated over a large peat dome that stores huge amount of carbon. 23 sample plots were established in the area burned in 2015. The regeneration of understorey, seedlings, and saplings was recorded in each plot. Meanwhile, peat depth and its maturity were identified to determine the soil characteristic of study area. After 3 years of fire, the area already covers densely by understorey mainly pakis udang (Stenochlaena palustris), pakis tanah (Nephrolepis exaltata), and resam (Gleichenia linearis) with depth of root zone reach about 40 cm in some plots. The native peat swamp species showed minimal regeneration during third years after fire due to understorey covering and limited number of surviving trees. The natural regeneration of woody species was dominated by bangun-bangun (Melicope glabra) and sepongol (Evodia sambuciana) which were calculated about 371 saplings/ha and 200 saplings/ha respectively. Those all two species also founded in the seedlings stage. The peat depth varied from 0.32 m to 4.71 m with peat maturity is dominantly hemic in the subsurface. This regeneration information provides useful indications for restoration options, which could be done by assisted natural regeneratio