Tropical plantations are rapidly expanding as a source of industrial wood. In Indonesia, such plantations are generally made of large mono-specific blocks interspersed with natural forest remnants (corridors). By 2050 the World will need an additional 66-101 million ha of forest plantations (54-81 millions for wood energy). Plantations are best suited to provide large quantity of uniform material (industrial wood, pulp wood) that is in increasing demand. The area of tropical natural forests that can be economically or legally logged is going to decline drastically
1) Plantations, as currently managed, may directly contribute to fragmentary processes on a landscape level, by reducing the inter-connectivity of natural/native vegetation patches. Habitats that maintain connectivity across landscape are commonly called biological corridors. They represent an option for balancing the goals of sustainable production on plantations with maintenance of biodiversity. 2) Corridors of the study area were mainly riparian forests, left untouched when surrounding logged/over forest was clear-cut for plantation stands. 3) The extant and value of these forest remnants vary as laws and regulations are somewhat unclear and/or left to the interpretation of the plantation company. In Kampar Kabupaten (district) the required riparian buffer width depends on river width, in Pelalawan Kabupaten it depends on branching. Current government regulations (REF) stipulates that 15-20% of any concession has to be set aside as corridors and conservation areas, especially in riparian areas. Also slopes over 40% must be conserved – but slope length has not been specified. The extant of conserved natural forest was between 12 to 26 % of a sector area. RAPPs interpretation of regulations has been that rivers less than 3m wide need no riparian buffer, Rivers more than 3 m wide need at least 25 m on each bank (nearly all corridors in RAPP concession fall into this category) more than 50m wide rivers need 250m corridor including actual river.
Given current rates of environmental transformation and increasing dependency on plantation forestry, further scientific inquiry into the potential environmental, ecological benefits provided by corridors is needed. 1)As the goal of protected areas has been to cover 10% of national land area (but varies from country to country), how to predict the biological responses to fragmentation across the landscape in "the other 90%" of terrestrial land area. 2)to develop better plantation management strategies and regulations at the landscape scale for improved biodiversity conservation, while maintaining economic profitability of the plantations.
Concession (or study) areas in Riau, in close proximity of Tesso nilo forest reserve.
One RAPP concession sector, Baserah– All sectors are mosaics of Acacia mangium stands from age 0 – 77 months (average 31), KPPN (germplasm conservation areas) and Riparian forest corridors dense road network. (1-6 roads in each cell, with average 3 roads/cell) Soils are well drained, forests are lowland rain forests, all sectors are converted from natural/secondary forests, which had been selectively logged especially from Dipterocarp species prior to plantation development.
Year 2000. Landscape is composed of mainly acacia mangium stands and inoperable area (land, which has villages or land which villagers has claimed for themselves) Young regeneration forests, home gardens, fallows=belukar By law, 10% of the concession area should be left as tanaman ungulan (fallows, home gardens) for local people for livelihood.
Majority of corridors are narrow (less than 50m wide), have medium crown closure, are dominated by medium river, with 2-5 m wide (49%), (51%) Most corridors were connected, through other corridors, to either conservation areas (KPPN) or remaining natural forest areas outside sector boundaries (like the Teso-Nilo forest). Corridors of the Baserah sector were shorter, more open reflecting less environmental sensitive management prior to 1997. Corridor width, length, crown closure and proportion of the cell set aside as corridor were highly positively correlated: the longest were generally the widest, had the highest crown closure and were found in cells with a high proportion of land set aside. Majority (over 60%) had some sort of disturbance, generally illegal logging activities, intersected by roads and silted (had water ponding). Canopy closure was lower in not-logged than in logged-over corridors. This result can be explained by two main reasons i) some corridors were not logged because originally very poorly stocked and with a degraded canopy, ii) logging gaps are quickly colonized by low, dense canopy pioneer species like Macaranga spp, thus increasing the canopy closure.
8 species, 1. survey: 84 individuals, 2.: 87 inds in corridors and 88 inds in KPPN EC:Presbytis melalophos Banded leaf monkey: Typical density for it – 26 individuals / km2 in Sumatran lowland forest, group size approx. 13, normally 2 groups per km2 EC:Macaca fascicularis – Long tailed macaque, 30 individuals/km2, group size 15, normally 2 groups per km2 Kebun karet: 0,8 ind/ha Di sepadan Sungai Onangan: 3,3 ind/ha long/tailed macaques are more or less restricted to riverine forests, figures thus for riverbank km2 in Ecology of Sumatra – was found also in plantations Comparison of the 30 cells where primate presence was recorded (pooled surveys) and of the 45 cells with connected corridors but no primate recorded show that most cell characteristics (proportion set aside, corridor width, complexity, number and length of roads, corridor quality) are not significantly different between the two groups. For significantly different characteristics, results are somewhat counterintuitive: cells with primates have wider rivers but a more open canopy and shorter corridors.
Nycticebus coucang and Tarsier bancanus NOCTURNAL. Primates species richness and abundance was in line with studies from Tesso nilo area. Elephants visit the borders of Teso East, which also has mineral lick sites for animals.
12 orders, Diptera, Hymenoptera, Odonata the most abundant Decrease in no of orders & individuals perpendicular to the river no matter how wide the river or corridor In Amazon , insect abundance and diversity usually increase in the understory near edges, propably because of increased understory plant density and productivity PESTS?
KPPN (germplasm conservation area) area was not completely undisturbed - consisting of nurseries, roads.. But it still was a larger natural forest area inside the sector.
Tesso Nilo, much more diverse with IF species accumulation curve per trees – comparable?
Similarity with KPPN??? Overall value in the whole system of corridors not in one or two
Most “important” tree species in 4 classes (IVI) = A species having a high importance value occurs with high density, occupies more space (especially poles and trees), and is distributed relatively more uniformly compared to species with a lower importance value 1) Most species with high IV in KPPN, had also high IV in green belts. 16 - 18 species in trees and poles with IV > 5, 15 species in Tiga puluh hills. Macaranga sp., a pioneer species, while found in most areas except new plantation at the sapling level, was found only in old plantations and KPPN are at the seedling level, and only in old plantations at pole level. Macaranga sp. is an indicator species of disturbance and was found only in old plantations.
Trees In all plantation types, Medang, Jambu-jambu, Kelat were the dominant tree species, with Medang being the most dominant. Kempas, a protected species growing mainly close to rivers and other riparian areas, was not found even at the seedling, sapling and pole level. Basal area = the basal area (m2) of individuals of a particular species as a proportion of the total basal areas of all species. Relative density = number of individuals of particular species as a proportion of the total basal areas of all species. Relative dominance = the combined basal area of a single species as a proportion of the basal area of all species. Relative frequency = the frequency of a given species as a proportion of the sum of frequencies for all species. Important Value Index (IVI) = the sum of relative density, relative dominance, and relative frequency. An exception, for seedling the Important Value Index is calculated using formula = sum of relative density and relative frequency. GRAPH ? food sources of those vegetation species with highest importance value at seedling, sapling, pole and tree levels.
1) It is not possible to preserve all forests to parks and reserves so obviously it is important what happens to the residual 90% of the forest estate. Many species will only be conserved within a matrix of protected and managed forests. 2) Natural forest corridors may, if appropriately managed and designed, be used to mitigate the negative impact of large scale industrial plantations on biodiversity by providing some degree of landscape inter-connectivity of remaining natural forest patches/areas.
1) Overall, the real potential for affecting future plantation landscapes is to provide incentives for better landscape/spatial design and management of those areas which are set aside from production for corridors and conservation areas. There is generally very little scope for affecting within-stand management regimes and techniques. 2) From a biodiversity and conservation biology standpoint Plantation landscapes should be designed so that on the one hand, the landscapes are penetrable and permeable for those biodiversity components which are of conservation concern in the area under consideration, and on the other hand, impenetrable and impermeable for pests, weeds, and invasives. Second,although this presentation has mainly had ecological point of view, we can’t forget that from a human/social standpoint, the priority must be to design plantation and manage landscapes in a way that minimizes the adverse impacts on the local people and communities living in and around these areas. 2)According to several studies forest fragments loose species after isolation = phenomenon called as species relaxation (Laurance, S Cp3) Connectivity for the primates was crucial, and even very narrow coridors stretching out from the border of natural forest into the plantation are important for pollinators
Ideally they would consist of various types of habitat, not just riparian forests – for this we should maybe accept that some of the riparian forests are lost. –
Prevention of illegal logging – many means for this by using gates in roads, limited road network system..company commitment as responsible wood buyer.. Road system layout should be developed thinking its effect on hydrology (picture of water ponding), connectivity.. ----------------------- First, leases on natural (selectively, logged-over) areas classified as HTI (i.e., for plantation development), are short, currently approximately 20 years. This could be considered as too short a period for the companies to fully commit to longterm (beyond the twenty years) planning. Furthermore, there are currently no longterm plans for the HTI areas after the current leases expire, and current lease-holders has no guarantee that their lease can be extended beyond the current lease period. This uncertainty is a further impetus for maximizing short-term incomes at the expense of longterm sustainable management. And hence corridors have been considered as pure constraints to maximizing short-term earnings.
Diversity in line with KPPN and natural forest, but: How many endemic species do we have there compared to natural forest or KPPN? How should we compromise/take into account these in order to preserve f. ex. interior old growth forest species? On average, forest fragments exhibit markedly elevated dynamics, apparently as a result of increased windthrow and microclimatic changes near forest edges. Mean mortality, damage and turnover rates are much higher within edges. What type of biodiversity do we want to maintain? There is evidence that ecosystem disturbance often leads to species or population changes, but not necessarily loss in “biodiversity”; Who has the right to decide what biodiversity needs to be kept? Endemism might be low although the biodiversity is high! Should regulations prefer wider, maybe more viable corridors in stead of possible sinks, narrow corridors, which though could better act as connecting links between fragments. And the final question: ..
Besides benefits (providing habitat, aiding ecosystem processes such as pollinating, maintaining water quality by shading streams, redusing the nutrient inflow..) corridors may act as population sinks (dead end, reduce reproduction)
Impact of corridor design and management in a large-scale industrial tropical plantation landscape
Impact of corridor design and
management in a large-scale
industrial tropical plantation
Conference on Biodiversity and Conservation Biology in
Plantation Forests, 27th – 29th April 2005
Plantation Forests in Indonesia?
Forested area: 113 million ha (land area: 191 million ha,
Sumatra 19 million ha)
Indonesian forests (million ha)
1.4 million ha industrial pulp wood plantation forest at
the end of 2001
50 % established on land cleared of natural forest
Companies plan to establish new plantations in Riau (Sumatra)
on peat, logged-over natural forest..
How well are the present corridors maintaining
How the management of the matrix surrounding
corridors influences their viability?
Effectiveness of wildlife corridors in tropical fast wood plantations
for conserving biodiversity is largely unknown.
Field-based experiments to test knowledge gaps difficult
Integrating studies of animal movement, species dispersal in
matrix conditions needed
GOAL simulation/model for varying corridor conditions in
landscape matrix to aid develop better plantation management
strategies & better, clearer regulations
Null - hypothesis: patterns of distribution are independent of
connectivity, width, distance to natural forest area, crown closure
and age of neighbouring plantation stands
recently cleared areas
mixed tree garden
oil palm plantation
Teso East, Teso
3 Plantation sectors
Structural parameters (connectivity to natural
forest/KPPN, distance, age of surrounding plantation,
crown closure, disturbance..)
Vegetation – 32 cells in one sector, Baserah
Grid of 100 ha square cells
total of 282 plots in transect lines in corridors - sampled area of
0.12 ha, 0.72 ha, 2.9 ha and 11.5 ha for seedlings, saplings,
poles and trees, respectively
Insects and mammals – line transects in three sectors, in
80 and 100 cells respectively perpendicular to river and
Distance from Natural Forest through green
Distance from Natural Forest (bird’s distance)
Number of Roads
Length of Roads (km)
Linkage with KPPN
Linkage with Natural Forest
Present in 30 % of cells
8 species ( (Hylobates agilis, H. lar, H. klosii, H.
syndactilus, Macaca fascicularis, M.
nemestrina, Presbytis femoralis, P. melalophos and one unidentified species of Presbytis)
One species ( M. fascicularis) in plots without corridors, none without
connection to natural forest/KPPN
Most common Presbytis melalophos (food generalist) and Macaca
However: a significant proportion (45%) of connected corridors had no
No explanation from cell structural characteristics for primate
presence/absence records … cells with primates had wider rivers
but more open canopy and shorter corridors.
The most common
primate species in
Sumatran lowland Plantation
forest (Ecology of Sumatra)
Riau Province Forest
Department survey in June
(Gillison, WWF) in 2001
10 7 1
10 2 8
Der mapt er a
Di t yopt er a
Col opt er a
Di t er a
Hemi t er a
Homopt er a
Hymen opt er a
I sopt er a
Lepi opt er a
Neur opt er a
Odon at a
O r de r
More abundant and rich
insect fauna within
Decrease in number of
orders and individuals
away from river
Or t hopt er a
13 25 37 49
61 73 85 97 109 121 133 145 157 169 181 193 205 217 229 241 253 265 277 289 301 313 325 337 349
Individuals in random order
KPPN: 134 tree species in 1.4 ha
Corridors: 275 tree species in 11.5 ha
Heavily logged forest: >900 vascular plant species/0,18 ha
Partially logged forest: 61-112 tree species/0.02 ha
All values are mean values based on
equal sampling effort
IV, corridor seedlings
IV, corridor saplings
IV, corridor poles
IV, KPPN seedlings
IV, KPPN saplings
IV, KPPN poles
IV, KPPN trees
IV, corridor trees
Dominant species with highest IV similar in KPPN and
Primate density correlated positively in corridors with
cumulative IV of those plant species known generally as
the most important food sources
The potential for tropical forest
plantations to contribute to
Biodiversity loss associated with
plantation development through Conversion of natural forests
Fast rotation time and shading of
Acacia mangium indigenous tree
species will not survive in the
Corridors the most potential
means maintaining biodiversity
What role for plantation forestry in
Landscape level management
Implies consideration of long
term viability of corridors –
within a comprehensive
landscape level plan,
implemented and monitored
stressing issues such as
Linkage to KPPN
and/or natural forest