investigating the effect of fire dynamics on aboveground

Investigating the effect of fire dynamics on the aboveground carbon storage in the Bateke landscape, Congo PhD research study

Paula Nieto Quintano, University of Edinburgh -------------------------

Dr Edward Mitchard and Dr Casey Ryan - UoE Dr Tim Rayden, Wildlife Conservation Society - Congo US Forest Service

INTRODUCTION – Fires in African Savannas

> Africa is often referred to as the “fire continent”

> Most fires occur in the savanna biome

> Previous research – Long term fire experiments

Burn season & timing affects its impact on the vegetation

Fire intensity & fire frequency have a big effect on tree survival rates

AGB reduced with increased fire frequency

Early Dry Season fires (May/June)

Cool fires, patchy -> Reduce fire frequency in late season

Lower mortality rates

More regeneration

Late Dry Season fires (Sept) High intensity

High mortality rates

Regeneration disrupted

The Bateke Plateau

> Bateke plateau: savanna-covered surrounded by rainforest. Located principally in the RoC

Saatchi et al. Global aboveground carbon map

Congo basin forest

Savanna

The Bateke Plateau

> Bateke plateau: savanna-covered surrounded by rainforest. Located principally in the RoC

> Kalahari sands. Not many herbivores

Kalahari sands

The Bateke Plateau

Change in woody cover of African savannas as a function of MAP (Sankaran et al., 2005).

> Bateke plateau: savanna-covered surrounded by rainforest. Located principally in the RoC

> Kalahari sands. Not many herbivores

> Average annual precipitation: 1,700-2,000 mm. Dry season from end of May to September.

> Fire is one of the primary determinants of savanna growth

> Few long term field studies on the impacts of fire in savannas / seasonality

> Bateke plateau largely unstudied

> Area is burned frequently (mainly dry season)

> With appropriate fire management, possibility to increase carbon storage

RELEVANCE / OBJECTIVES

> Understand the woody cover, productivity, carbon storage and fire regime of the complex forest/savanna system of the Bateke

> Quantify the relationships between fire intensity/frequency, woody cover and AGB of the Bateke Plateau

METHODOLOGY

Control Fire regimes: • Annual Early Dry

Season (EDS) • Annual Late Dry

Season (LDS) • No burning

Predict carbon sequestration rates and total

carbon stocks under different fire regimes

Temporal & Spatial Analysis of fires

Biomass

DALEC

AIM 1: Aboveground Biomass and floristic characteristics of the savannas in the Bateke Plateau. Determine mortality and growth rates.

RESEARCH QUESTIONS

> RQ1. Quantification of the biomass in the plots and how it is

distributed?

> RQ2. What is the floristic characterisation of the plots?

> RQ3. What are the mortality, growth and regeneration rates, and how

do they vary under different fire regimes?

1. Field experiment METHODOLOGY

1. Field experiment METHODOLOGY

• 3 permanent plots in two sites. 3 fire regimes:

> Annual Early Dry Season > Annual Late Dry Season > No burning

2 STUDY SITES

LEFINI RESERVE

LESIO-LOUNA RESERVE

1. Field experiment METHODOLOGY

• 3 permanent plots in two sites. 3 fire regimes:

> Annual Early Dry Season > Annual Late Dry Season > No burning

Inventory of trees - DBH > 9cm - Sps - Height - Status

Species (grasses & plants)

Inventory all saplings Grass Biomass (DPM)

Soil

Soil samples

PLOTS SUBPLOTS

2015

Lefini Reserve

> Woodland savanna (Hymenocardia Acida) with riverine forest

Riverine forest

Savanna

Lefini Reserve

> Woodland savanna (Hymenocardia Acida) with riverine forest

Savanna

Riverine forest

Gite

LDS (1)

Lesio Louna Reserve – Aspinal Gorilla camp

> Woodland savanna (Hymenocardia Acida) with riverine forest > Fire exclusion areas for 15-20 years – forest expansion

> Woodland savanna (Hymenocardia Acida) with riverine forest > Fire exclusion areas for 15-20 years – forest expansion

No Burn (6)

Riverine forest

Camp

Lesio Louna Reserve – Aspinal Gorilla camp

Trees • Around 1200 trees per plot Stem density ~ 50 (stems/Ha) • Main sps Hymenocardia acida (Strychnos Pungens and Syzygium guineense) • AGB

1. Fire Experiment Some results

Tree inventory Tree species composition Plot

Tree species 1 2 3 4 5 6 Albizia 0 0 0 1 1 0

Annona senegalensis 0 0 0 1 0 1

Bridelia 0 0 0 4 0 0

Hymenocardia acida 944 1485 1731 1108 855 572

Ikourou 0 0 0 2 0 0

Maprounea africana 0 3 97 5 0 0

Strychnos cocculoides 0 0 0 2 0 0

Strychnos pungens 1 3 7 10 2 0

Syzygium 0 0 0 47 226 4

Vitex 0 1 0 1 0 0

Total trees

DBH>9

AGB

(Tonne/Ha)

Stem

density

LEFI

NI Plot 1 LDS 945 1.04 37.8

Plot 2 EDS 1795 2.35 71.7

Plot 3 NB 1834* 4.76 73.4

LESI

O Plot 4 EDS 1181 1.80 47.2

Plot 5 EDS 1084 1.59 43.4

Plot 6 NB 577* 1.21 23.1

* DBH > 11cm

SUBPLOTS

Number of grass species 23

Number of plant species 34

Grass and plant species composition (subplots)

Trees • Around 1000 trees per plot Stem density ~ 50 (stems/Ha) • Main sps Hymenocardia acida (Strychnos Pungens and Syzygium guineense) • AGB

1. Fire Experiment Some results

AGB vs. DBH classes

Grasses • Loudetia simplex - Hyparrhenia diplandra • AGB

1. Fire Experiment Some results

Comparison between tree and grass biomass plots 1,2,4 and 5

Bio

mas

s (t

on

ne/

ha)

Gra

ss B

iom

ass

(to

nn

e/h

a)

Tree Biomass (tonne/ha)

1. Fire Experiment Some results

Early Dry Season Fire Late Dry Season Fire

FIRES Mortality % Average growth per year

EDS fires low intensity patched fire 25/70 % of the plot burnt

1.4 0.12 cm

LDS fires more intense 100% of the plot burnt

~1.8 0.14 cm

RESEARCH QUESTIONS

> RQ1. What are the dynamics of woody cover and fire frequency from 2000-

2015?

> RQ2. Are there seasonal variations (EDS vs LDS Fires) of fire intensity/density?

> RQ3. Are there relationships between fire return time and AGB? And between

AGB and other spatial variables (soils, elevation or slope)?

> RQ4. Is there any relation between fire dynamics and spatial variables

(protected areas, accessibility, vegetation type, soils,..)?

2. Remote Sensing Analysis METHODOLOGY

MODIS (2000-2015) 250m/Daily

> Active Fire MCD14ML (FRP) and Burned Area product MCD45A1

2. Remote Sensing METHODOLOGY

Fire occurrence and intensity

Landsat 7/8 30 m / 16 days

> Canopy cover mapping > Fire scar mapping (validation for MODIS)

Alos 2 PALSAR (2016) L band (~20m)

> Biomass

LEFINI LESIO LOUNA

Fire Frequency Study Areas (2000-2014) – Active fires from MODIS

2. Remote Sensing Some results

Legend

firefrew_Lefini

<all other values>

Join_Count

0

1

2

3

4

5

6

7

8

Fire Freq. (years)

LEFINI LESIO LOUNA

Active fires 2014 (MODIS active fire data)

2. Remote Sensing Some results

Example ALOS2 Palsar - Lefini 2016

2. Remote Sensing Some results

Next steps

• Continue fire experiment • Next 12 moths: - Remote sensing analysis - Modelling

Thank you for your attention!

paula.nieto@ed.ac.uk

Grasses • Loudetia simplex - Hyparrhenia diplandra • AGB

1. Fire Experiment Some results

Comparison between tree and grass biomass inside the plots

KEY OUTCOMES

• Promote improved management of this area to enhance biodiversity and carbon storage

• Additionally this would sequester carbon from the atmosphere, increased soil fertility, and it will also have multiple benefits to the local populations.

• The longer term research experiments should potential for REDD+ projects

• Provide very valuable information about the Bateke landscape, as there is a relatively limited understanding of this ecosystem.