DR. HJH DULIMA JALI,

GEOGRAPHY & ENVIRONMENTAL STUDIES PROGRAMME,

UNIVERSITI BRUNEI DARUSSALAM

BARRIERS TO SEEDLINGS REGENERATION IN FIRE-DAMAGED TROPICAL PEATLAND OF BRUNEI

DARUSSALAM

International Conference on Wetland Forest, 22-23 March 2012, Rizqun International Hotel,Bandar Seri Begawan, Brunei Darussalam

Introduction

� Destruction of Southeast Asia’s peat swamp forest is widely acknowledged to be a serious problem, causing degradation of water catchments, losses of biodiversity and exacerbating rural poverty.

� Most countries are now attempting to solve the problem by protecting remaining forest and launching large restoration project to meet local and national objectives, including countries’ international obligations following the United Nations Conference on Environment and Development.

� Large-scale restoration of complex tropical peatland forests is a comparatively modern dilemma, which has been approached in a variety of ways.

Selection of Approaches

• To select an appropriate approaches to forest restoration a manager needs to asses actual and potential levels of natural regeneration and this demands a high inputs of ecological information of each site.

• It also requires an understanding of the factors limiting successional change and increases in desired species towards thedesired objectives.

• Directing natural successional processes towards the desired goal requires an understanding of the processes driving succession and limitations that halt natural recovery.

• These include: − Functional hydrological condition.− Soil ConditionNutrients status and cycling− Energy flow processes

Why need to identify factors that hamper / arrest regeneration processes?

� It is essential to understand the mechanisms of regeneration and succession and the ecological dynamics of an ecosystem for effective and realistic management planning.

� These are crucial for the interpretation of the high spatial-temporal variability found in post-fire species performance.

� Such knowledge also necessary to assess the potential of different regeneration mechanisms to cope with ongoing land-use and climate change.

UNDERLYING CAUSES HALTING / ARRESTING NATURAL SUCCESSION

� Many studies throughout the neotropics tropical forests have shown that a number of interacting factors may impede tropical forest natural regeneration.

� These include :

� Disturbance: fire, Drought, herbivories, anthropogenic

� Site Resources: water, soil nutrient availability

� Competition from weeds.

� Roots competition.

� Plants and propagule availability: Seeds banks, seed rains

� Seed dispersal limitations,

� Seeds / seedlings predation

� Distant from existing forests

Identifying the Limitation

Study Area

This study was conducted in the Belait - Badas Peat Swamp, in Brunei Darussalam (4°15'-4°39'N, 114°05'-l14°29'E) an area of state land statute under the jurisdiction of Forestry Department of Brunei

The Study Area

Objectives of the Study

� To develop a better understanding of the underlying ecological processes in regeneration of fire affected peat swamp forest of Badas, Brunei Darussalam

� To investigate / identify the biophysical barriers to the colonization and natural regeneration of the plant communities in burnt areas that have been invaded by ferns

and sedges.

Methods

o Seedlings of several timber three timber species Agathis alba, Shorea pachyphylla, Dryobalanops rappa and non-timber tree species were planted in each transects and their growth were monitored for three years at 1 – 3 intervals.

o The growth of naturally established peatland species were also monitored.

o Seeds of several typical peatland species ( Timonius spp, Tetractomia spp, Ficus spp. saga, mempening)are disperse randomly.

o Treatment: Control (no cutting), clearing weeds.o Dispersing seeds of non-timber species randomly

RESULTS

� Factors that dictated natural regeneration of seedlings are:

� Site Hydrological Condition: site particularly the depth of the water-table

� Wet Site

� Natural regeneration flourish in site with high water table ( < 20 cm below surface)

� Dominant species: Tetractumia beccari, Eugenia spp, Litsea spp, Hoorsfieldia crassifolia.

� Dry Sites� Vigorous growth of early post fire colonizers Stenochlaena palustris, Pteridium aquilinum and Blechnum indicum that cover almost the entire surface with their strangling stems or dense leaves

� This condition significantly hamper the establishment and growth of seedlings.

� At least five species of woody plants - Teminius, Horsfieldia, Syzygiumspp, Ficus and Uncariaspp have the capacities to germinate directly within the less dense stand of ferns and grasses, indicating these species high competitive ability and adaptability to a wide range of abiotic circumstances.

Survival Rates of planted seedlings

Timber Seedlings 90 %

Control 0 % < 2 %

Cut weeds Once 0 % 3 %

1 – 3 months cut 65 – 85 % 70 -85 %

Agathis 70 -80 %

Dryobalanops rappa 60 – 75 %

Shorea pachyphylla (1 yr) 80 – 90 %

Non-timber species 85 – 95 %

Survival of Each species group

Environmental condition ( 2005 – 2009) is relatively good with no lengthy rainless period.

Competition with ferns and grasses

� If seedling managed to establish among the ferns their growth are greatly reduced.

� Seedlings are overgrown by the ferns and remain covered and hidden between the ferns resulting in deformed stems.

� Demonstrated by the growth of planted seedlings, especially the Agathis seedlings.

� The seedlings growth is boosted as soon as they escaped from the ferns that are when the ferns are removed.

� Controlling the growth of ferns and grasses caused significant changes in the species composition as more seedlings appear particularly Teminius spp and several species of Ficus, Eugenis, Calophyllum and Uncaria.

Agathis seedlings covered by ferns

Growth of Agathis after released from ferns, with deformed stems. Growth increased dramatically once seedlings emerged above the fern canopy

Inhibitory characteristics of ferns & sedges

Growth of fern after fire

Lack of seeds

� The seed bank is likely to be exhausted by the fire because the organic nature of the substrate would have produced intense heat that would have destroyed any available seeds.

� More trees regenerating nearer to undisturbed forest.

� Dominant species are Lithocarpus sundaica (mempening); Eugenia spp. (ubar); Baccaurea bracteata ( tampoi antu), Calophyllum spp (bintangor)

Limited dispersal mechanisms & activities

� Large treeless areas are unattractive to most frugivorous dispersers.

� Extensive growth of early colonizer of fern and sedges communities limited dispersal activities given that grasses and fernlands offer few resources that attract seed dispersers particularly the birds and small mammals.

� Seeds dispersal therefore appears critical in determining the diversity, density, and location of natural regeneration.

� Perching sites such as isolated trees can accelerate ecological succession processes.

� Most generating species are birds dispersed

Evident of Dispersers

Existing surviving trees and distant from forest edge

� The existence of surviving timber trees also showed some influence on the regeneration processes.

� These survivors appear to facilitate recolonization as indicatedby the appearance of several different seedlings that establish around the surviving trees.

� They appear to perform a probable mode of dispersal by acting as perches to birds that play a significant role in the dispersal of small seeds.

� In addition these surviving trees cast shade that limit the growth of ferns and grasses that otherwise limit the germination of tree saplings.

� There is no indication that the surviving trees act as seed sources as those seedlings are of totally of different species.

Regeneration around surviving trees

Application of assisted natural regeneration (ANR)

� As clearing eliminates the fern while enhancing the performance of most tree seedlings suggests that planting trees to overcome dispersal limitations and produce a shade cover is the best way to eliminate the ferns.

� Once trees are established, they may act as regeneration nuclei by attracting seed dispersers and providing favorable growing conditions, thereby accelerating natural regeneration.

� So application of assisted natural regeneration (ANR) offers efficient, low-cost forest restoration method that can effectively hastened regeneration of vegetation.

IMPLICATION FOR PRACTISE

Conclusion

� There are a several interacting factors that impose barriers for the growth and survival of this seedling and arrest the natural succession.

� The results of the study emphasize the predominant effect of competition, effective seed dispersal (a combination of dispersal and survival) and hydrological regime in affecting species composition and the seedling growth.

� It also highlights the need for management intervention in restoring the peatland floristic diversity.

� Approach of overcoming the barriers to, and acceleratenatural successional processes are by removing or reducing the barriers: - competition with weedy species, manipulation of tree stands and addressing the recurrence of fire

Growth of Agathis & Drybalanop rapa

Excellent growth of Shorea pachyphylla,

Defoliation and resprouting of Dryobalanops rappa.

Problems

Damage by animals

Unknown cause of death: Most likely root predation

THREATS : Logging

Threats: Sand Mining

FIRE (June 2009)

Oct 2010

THANK YOU FOR YOUR

ATTENTION