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Results of Rick’s Project for His Honour’s Project

Hi all,

Rick here. After eight month’s of  work on my final year project, I’m proud to announce some of the findings of the project. They are summarized in the poster below.

However, it is not the end of my project, I’ve got more trees to map and I need help from you! Refer to the end of the page for sign-up links to help me out with my project!

Here’s an overview of my project (for both new and old readers)

Aims:

(1)Map the surface  elevation of Mandai mangrove

  • I am curious to know surface elevation of Mandai i.e. if the elevations in the mangrove are relatively the same at different mangroves?
  • What types of topography can be seen in Mandai?
  • Surface elevations will consolidated into a  digital elevation model (DEM)

(2)Map the vegetation of the mangrove, specifically mangrove trees

  • What types of mangroves tree species are found in Mandai
  • Are these trees clustered together? Is there  a difference in spatial distribution of trees according to species? and etc.

(3)Investigate if there’s a relationship between mangrove trees and surface elevation

  • Mangrove trees may be distributed according to species at different surface elevations
    • this could be due to adaptation of a specific species with the physical environment it lives in
    • different species have different strategies of dispersing their seeds; some mangrove fruits are able to propagate with floating propagules by wave action
  • Is there “mangrove zonation” in Mandai? i.e. distribution of  mangrove species found  at different distances from the shoreline

    Is zonation found in Mandai mangrove similar to the figure above?

Is zonation found in Mandai mangrove similiar to the figure above?

Introduction

Where is Mandai mangrove?

It is located just next to Woodlands Checkpoint and the causeway. Here’s the location on Google Maps.

Q: How did I map my trees and surface elevation?

A: I used a total station

Trees and surface elevation were mapped using a total station which comprises of the optical machine(theodolite operated by JK), survey prism (held by Rachel) and target prism(not seen here).

Results 

Q: Did I managed to map every single tree in Mandai?A: No, however the tally so far  is 1490 trees. Mapped trees were focused at Mandai Kechil (near Mandai Kechil River) and in transects across the mangrove.

Q: How many species of trees did I mapped?A: 13 species, I only focused true mangrove species and those with tree girth of  5cm and above. They are

Species Species Code Family
Avicennia alba Blume

AA

Avicenniaceae
Avicennia officinalis L.

AO

Avicenniaceae
Avicennia rumphiana Hallier f.

AR

Avicenniaceae
Bruguiera cylindrica (L.) Bl.

BC

Rhizophoraceae
Bruguiera gymnorrhiza (L.) Lamk

BG

Rhizophoraceae
Ceriops tagal (Perr.) C. B. Robinson

CT

Rhizophoraceae
Ceriops zippeliana Blume

CZ

Rhizophoraceae
Excoecaria agallocha L.

EA

Euphorbiaceae
Heritiera littoralis Dryand. In Aiton

HL

Malvaceae
Lumnitzera racemosa Wouldd

LR

Rhizophoraceae
Rhizophora apiculata Bl.

RA

Rhizophoraceae
Rhizophora mucronata Lamk.

RM

Rhizophoraceae
Sonneratia alba J. Smith

SA

Sonneratiaceae
Xylocarpus gratanum Koenig

XG

Meliaceae

Q: What are some of the  endangered mangrove species that I have mapped?A: These species are known to be endangered or vunerable according to Singapore Red Data Book

Heritiera littoralis (dungun)

Picture courtesy of Ria Tan from Wild Singapore

Ceriops tagal (tengar putih)

Picture courtesy of Ria Tan from Wild Singapore

Ceriops zippelana (tengar merah)

Picture courtesy of Ria Tan from Wild Singapore

Q: How about mapping the surface elevation? 90% completed.A: Here’s the DEM with the location of trees mapped overlaid on the DEM. 4754 elevation points were taken to produce the DEM.

DEM of Mandai mangroves and the locations of mapped trees in and outside transects

Q: How about distribution of tree species vs. surface elevation gradient?

Certain tree species were found at lower elevations e.g. Sonneratia alba and Rhizophora apiculata. At highest elevations, Excoecaria agallocha and Lumnitzera racemosa were foundThere was alot overlapping of distributions across the surface elevation gradient for many species.

Grouping of species according to pair-wise distribution of surface elevation range tests. Four groups (in blue box groupings) are distributed across an surface elevation gradient. Alternatively, overlapping Bruguiera gymnorrhiza would provide a standalone Avicennia alba grouping and a larger group consisting of A. rumphiana, A. officinalis and B. cylindrica.

Conclusion

Q: So what can I conclude about my results?

“Mangrove zonation” most probably does not exist in Mandai. Such observation could be explained by its history of human and natural disturbances. Perhaps,  non-pristine mangrove sites such as Mandai (any site outside Mandai) may not show any form of mangrove zonation.

Q: So, what now?

More mapping is needed to certify the preliminary results since there is  an estimated 70% of mangroves trees left to mapped in Mandai!

VOLUNTEER RECRUITMENT

For those who are interested to help me with my project, please click  on the following weblink and fill up the form! Thanks!

http://tinyurl.com/6sp4yh9

Cheers,

Rick

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