Liana abundance and distribution along a disturbance gradient in the tropical forest of French Guiana

94 Pages·2016·2.26 MB·English

by  Jana Roels

Faculteit Bio-ingenieurswetenschappen
Academiejaar 2015 – 2016

Liana abundance and distribution along a disturbance
gradient in the tropical forest of French Guiana

Jana Roels
Promotor: Prof. Dr. ir. Hans Verbeeck
Tutor: Dr. ir. Elizabeth Kearsley

Masterproef voorgedragen tot het behalen van de graad van
Master in de bio-ingenieurswetenschappen: Bos- en natuurbeheer

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Gent, juni 2016

Prof. Dr. ir. H. Verbeeck J. Roels
Acknowledgements
An intense learning process, that existed out of fieldwork, reading, understanding and writing,
has now ended. Without the help, knowledge, information and support from so many people,
this wouldn’t have been possible. I owe my gratitude to all those people and I want to thank
everyone appropriately.
My greatest gratitude goes to Prof. Dr. ir. Hans Verbeeck. It was a precious and instructive
opportunity to work on this project and to have had the chance to go abroad. I also want to
thank you for your advice, sharing your experience and reviewing my work.
I am enormously thankful to my supervisor Dr. ir. Elizabeth Kearsley for always showing me
the right direction, answering my questions and the critical remarks on my work. I am very
grateful to have had the opportunity to learn from you.
Furthermore, the fieldwork for this study wouldn’t have been possible if it wasn’t for Bruno
Hérault, principal investigator of Paracou Research Station (CIRAD), and Damien Bonal,
principal investigator of the Guyaflux flux tower site (INRA). I want to thank Damien Bonal for
guiding us through the Guyaflux plots, sharing information and to give us the opportunity to
conduct fieldwork. I am also grateful to Bruno Hérault for the valuable information concerning
the disturbance plots, for always answering my questions and for allowing us to utilize the
disturbance plots to do research. Additionally I also want to show my gratitude to Aurélie
Dourdain, GIS specialist for CIRAD, for her expertise and time.
Also a special thank you to Hannes De Deurwaerder for your hard work and your positive
energy during the field work, it was lovely to work with you. I also offer my thanks to both
Manfredo Di Porcia and Marijn Bauters for their help with difficulties and making time for me,
it meant a lot. To Nancy Pausenberger, thank you for your help with the inventory, as well as
for the good times we had together in French Guiana. Also Mario Vaneechoutte deserves a
special mention for his critical opinion and review.
To Thomas Mertens, thank you for believing in me and your unremitting encouragement. Your
support and love mean everything to me. I also want to thank my friends for being there for
me, supporting me and listening to me, you are all amazing.
At last, but not the least, I want express an enormous gratitude to my parents. Above all, for
the opportunity to let me make my own choices in life and always supporting me. It is because
of you that I was able to follow this education and I will be forever grateful for that.
Samenvatting
In deze studie wordt de gemeenschap lianen in Paracou Field Station, gelegen in Frans-
Guyana, onderzocht. In september 2015 werd het veldwerk uitgevoerd waarbij alle lianen
(diameter ≥ 2cm) werden geïnventariseerd in zowel onverstoorde (9 plots met een totaal
oppervlak van 4.92 ha) als verstoorde (5 plots met een totaal oppervlak van 5 ha) plots. De
verstoring werd uitgevoerd gedurende de periode van 1986-1988 door CIRAD, en bestond uit
een exploitatie experiment met drie gradaties in intensiviteit.
De onverstoorde plots worden gebruikt als referentie, waardoor het mogelijk is om de invloed
van de verstoring op de huidige lianengemeenschap na te gaan. Een significant (p < 0.01)
hoger aantal lianen werd waargenomen in de verstoorde plots (256.2 ± 39.4 individuen/ha) in
vergelijking met de onverstoorde plots (142.2 ± 26.4 individuen/ha). De biomassa daarentegen
was niet significant verschillend. Bij de verstoorde plots waren voornamelijk significant meer
lianen aanwezig in de eerste twee diameterklassen (2-3 cm en 3-4 cm), in vergelijking met de
onverstoorde plots. In de onverstoorde plots maakten lianen voor 22.1 ± 4.2% deel uit van alle
houtige individuen, vergeleken met 38.2 ± 6.3% in de verstoorde plots.
Verder werd ook nagegaan of een spatiale relatie bestaat tussen de antropogene verstoring en
de huidige lianengemeenstap. Finaal werd een analyse doorheen de tijd gemaakt waarbij de
link tussen de huidige lianenverdeling en de natuurlijke verstoring werd nagegaan, startend in
1995.
Er kan geconcludeerd worden dat 30 jaar na de antropogene verstoring de invloed nog steeds
waar te nemen is in de huidige lianenabundantie, maar niet in de biomassa van de lianen. Een
spatiale relatie tussen de lianenverdeling en zowel natuurlijke als antropogene verstoring werd
niet gevonden. Naar de toekomst toe, is het aangeraden om bij gelijkaardig onderzoek een
voldoende groot oppervlak te selecteren, alsook de lianen te identificeren op soort. Voorts zijn
er meer onderzoeken op lange termijn nodig om voldoende kennis te vergaren t.a.v.
lianensuccessie en de respons van lianen op verstoring.
Op vlak van beleid wordt aangeraden om rekening te houden met de impact van de hogere
proliferatie van lianen op de dynamiek van bossen na het kappen van bomen. Dit kan gedaan
worden door het opvolgen van de competitie tussen lianen en bomen die ontstaat in de
openingen en zo de veranderingen in demografische processen van de bomen te reduceren.
Deze maatregel kan worden toegevoegd aan de andere ‘reduced impact logging’ technieken,
waaronder het verwijderen van lianen voordat de houtexploitatie plaatsvindt.
Abstract
In this study, the liana community in Paracou Field Station, French Guiana, is investigated. In
September 2015 the field campaign was carried out, where all lianas (diameter ≥ 2 cm) were
inventoried in both undisturbed (9 plots with in total an area 4.92 ha) and disturbed (5 plots
with in total an area of 5 ha) plots. The disturbance was executed during the years 1986-1988
under the management of Bruno Hérault, CIRAD, and existed out of a logging experiment with
three different degrees of intensity.
The undisturbed plots are used as a reference so it is possible to examine the influence of the
disturbance on the present liana communities. A significant (p < 0.01) higher amount of lianas
was found in the disturbed plots (256.2 ± 39.4 individuals/ha) compared to the undisturbed
plots (142.2 ± 26.4 individuals/ha). The biomass however, was not significant different. For the
disturbed plots, significant more lianas were present in the first two diameter classes (2-3 cm
and 3-4 cm) compared to the undisturbed plots. In the undisturbed plots lianas constituted
22.1 ± 4.2% of the woody individuals, compared to 38.2 ± 6.3% in the disturbed plots.
Furthermore, a spatial relation of the anthropogenic disturbance with the present liana
community is investigated. Finally, an analysis, through time, on the link between the present
liana distribution and the natural disturbance is made, starting in 1995.
It is concluded that 30 years past anthropogenic disturbance the influence is still noticeable in
the liana abundance, but not in liana biomass. No spatial correlation was found between liana
distribution and both natural as anthropogenic disturbance. Towards the future, it is
recommended to select a large study area and to determine liana species. Furthermore, more
long term studies on lianas are needed for more knowledge on the succession of lianas as for
their the response to disturbance.
Policy wise it is suggested to take this influence of liana proliferation on forest dynamics into
account when conducting wood exploitations. A way to do this is to perform a follow-up of the
logging gaps for liana versus tree competition and try to reduce the changes in demographic
processes of the trees. This can be added to other reduced impact logging techniques (RIL),
such as pre-logging liana cutting.
Contents
List of abbreviations ............................................................................................................................... i
List of figures ......................................................................................................................................... ii
List of tables ......................................................................................................................................... iii
1. Introduction .................................................................................................................................. 1
2. Literature review .......................................................................................................................... 3
2.1. Tropical forests in a changing environment .......................................................................... 3
2.2. The ecology of lianas ............................................................................................................. 4
2.2.1. Liana diversity ................................................................................................................ 5
2.2.2. Functional traits of lianas .............................................................................................. 6
2.3. Lianas in the forest ................................................................................................................ 8
2.3.1. Interactions and competition between lianas and trees .............................................. 8
2.3.2. Influence on nutrient transport .................................................................................. 11
2.3.3. Lianas and animals ...................................................................................................... 12
2.4. Demography of lianas ......................................................................................................... 12
2.4.1. Pantropical similarities and differences in liana distribution ...................................... 13
2.4.2. Influence of environment and climatic variables on liana distribution ...................... 14
2.4.3. Gap dynamics .............................................................................................................. 17
2.4.4. Composition and colonization during succession ....................................................... 18
2.5. Liana proliferation and its drivers ....................................................................................... 19
2.5.1. Increased evapotranspirative demand ....................................................................... 20
2.5.2. Increasing rates of natural disturbance ...................................................................... 21
2.5.3. Anthropogenic disturbance ......................................................................................... 21
2.5.4. Elevated atmospheric CO ........................................................................................... 22
2
2.6. Reduced impact logging (RIL) .............................................................................................. 22
3. Materials and methods .............................................................................................................. 25
3.1. Study area ........................................................................................................................... 25
3.2. Liana inventory .................................................................................................................... 30
3.3. Comparison between undisturbed and disturbed plots ..................................................... 31
3.3.1. Diameter distributions and biomass estimations ....................................................... 31
3.3.2. First host tree .............................................................................................................. 32
3.4. Influence of logging disturbance ......................................................................................... 33
3.5. Link with natural disturbance .............................................................................................. 34
4. Results ........................................................................................................................................ 36
4.1. General analysis of inventory .............................................................................................. 36
4.1.1. Diameter distributions and biomass estimations ....................................................... 36
4.1.2. First host tree .............................................................................................................. 39
4.2. Comparison of different treatments for disturbed plots .................................................... 40
4.3. Spatial distribution of lianas and possible link with disturbance ........................................ 43
4.4. Possible link with natural disturbance ................................................................................ 43
5. Discussion ................................................................................................................................... 47
5.1. Differences in characteristics between undisturbed and disturbed plots .......................... 47
5.1.1. Liana abundance ......................................................................................................... 47
5.1.2. Biomass ....................................................................................................................... 49
5.1.3. Diameter distributions and basal area (BA) ................................................................ 51
5.2. Traits of the first host tree .................................................................................................. 53
5.3. Spatial distribution of lianas ................................................................................................ 55
5.4. Link with natural disturbance .............................................................................................. 57
5.5. Management ....................................................................................................................... 58
6. Conclusion .................................................................................................................................. 60
7. References .................................................................................................................................. 61
8. Appendix ..................................................................................................................................... 73
8.1. Exceptions and alternative POMs ....................................................................................... 73
8.2. Stem densities undisturbed plots........................................................................................ 75
8.3. Stem densities disturbed plots ............................................................................................ 75
8.4. Liana and tree abundance per undisturbed plot ................................................................ 77
8.5. Ripley’s L plot 2 ................................................................................................................... 79
8.6. Ripley’s L plot 3 ................................................................................................................... 80
8.7. Ripley’s L plot 5 ................................................................................................................... 81
8.8. Ripley’s L plot 7 ................................................................................................................... 82
8.9. Ripley’s L plot 12 ................................................................................................................. 83
i
List of abbreviations
A Photosynthesis
AGB Aboveground biomass
BA Basal area
BCI Barro Colorado Island, Panama
CIRAD Institute Agricultural Research for Development
CL Conventional logging
CSG Centre Spatial Guyanais
DBH Diameter at breast height
DSL Dry season length
ETR Electron transport rate
FAO Food and Agriculture Organisation of the United Nations
GLD Global Liana Database
H Most intensive treatment conducted by CIRAD in the disturbed plots
ID Infestation degree
INRA French National Institute for Agricultural Research
IPCC Intergovernmental Panel on Climate Change
L Least intensive treatment conducted by CIRAD in the disturbed plots
LAR Leaf area ratio
LES Leaf economics spectrum
LL Liana load
LLS Leaf life span
M Treatment of intermediate intensity conducted by CIRAD in the disturbed plots
MAP Mean annual precipitation
NDD Negative density dependence
PDD Positive density dependence
PFD Photon flux density
POM Point of measurement
RIL Reduced Impact Logging
SLA Specific leaf area
TAGB Total aboveground biomass
WD Wood density
ii
List of figures
Figure 1: Relationship between liana abundance and mean above-ground tree biomass. ........ 8
Figure 2: Interaction between liana loads and crown position. .................................................. 9
Figure 3: Effect of lianas on the diameter growth, survival, and reproduction of their host
trees. ......................................................................................................................................... 10
Figure 4: Biogeographical differences in mean liana density and diversity. ............................. 13
Figure 5: Diameter class distribution of lianas in Central Amazonia. ........................................ 14
Figure 6: Relation between mean annual precipitation and abundance of liana, trees and
shrubs in different regions. ....................................................................................................... 14
Figure 7: Height growth grate compared between trees and lianas for wet and dry season.
................................................................................................................................................... 15
Figure 8: Land cover map of French Guiana and the plot locations. ......................................... 26
Figure 9: Annual climate pattern at Paracou............................................................................. 27
Figure 10: Composition of a ‘logging plot’................................................................................. 28
Figure 11: Graph with the original biomass against intensity of disturbance. ......................... 29
Figure 12: Measurement and tagging of lianas. ....................................................................... 31
Figure 13: Mean amount of lianas per DBH class for both undisturbed and disturbed plots.
................................................................................................................................................... 38
Figure 14: Mean amount of trees per DBH class for both undisturbed and disturbed plots.
................................................................................................................................................... 38
Figure 15: Liana load for WD, DBH and height of host tree for both undisturbed and disturbed
plots. ......................................................................................................................................... 41
Figure 16: Amount of trees against amount of lianas per treatment. ...................................... 42
Figure 17: Biomass of trees against biomass of lianas per treatment. ..................................... 42
Figure 18: Basal area of trees against basal area of lianas per treatment. ............................... 42
Figure 19: Liana distribution and disturbance polygons for disturbed plots. ........................... 44
Figure 20: Boxplots with infestation degree. ............................................................................ 45