This document summarizes a study on how microclimate affects the natural regeneration of forests in dryland areas of Portugal after agricultural abandonment. The study found that the rate of regeneration of holm oak trees depends on local microclimate conditions, with regeneration being faster in areas with higher potential solar radiation and slower in areas with lower potential solar radiation. The researchers developed a predictive model for holm oak regeneration based on microclimate variables that can help improve reforestation planning efforts. Validating the model over time showed it has potential for predicting natural regeneration patterns under different climate scenarios.

1. Improving ecosystem services in drylands:
Microclimate matters for the natural regeneration
of forests after agriculture abandonment
Cristina BRANQUINHO1, Adriana SILVA1, Pedro PINHO1,2, Alice
NUNES1,3, Giulia GAIOLA1, Lúcio ROSARIO4, Otília CORREIA1
1Universidade de Lisboa;
2Universidade Técnica de Lisboa;
3Universidade de Aveiro;
Ciência 2007
4Instituto de Conservação da Natureza e Florestas;
LTER/BIA-BEC/0048/2009
PTDC/AAC-CLI/104913/2008

2. The Question
The Drylands in Portugal
Climatogram 85-07
Mediterranean
Aridity Index
ICNF
Climatogram for Monte da Caparica, average values from 1985
to 2007

3. In drylands ecosystem
The Question functionality is restricted Tree Key Species
to few species
Portugal: from climate to vegetation
Climate Vegetation
Quercus ilex
Montado
Mediterranean
Ceratonia siliqua

4. Study Area Intensive wheat Campaigns
Cut of the tree stratum
During 1929-1949
Moura, Beja
5,270 ha
Reforestation
Why this area?
- It is a dryland.
- It has Quercus ilex woodlands
> 50 years with natural regeneration
--It is a LTER Site (Long Term Ecological Research >30 years)
- There are historical information about the management

5. Reforestation efforts since agriculture
abandonment in the 50`s-60´s
1965 1995
1. We need to understand better what are the
variables that limit the survival of this species under
Mediterranean climate.
2. For that we need to understand the mechanisms of
2009 2010
natural regeneration of Holm Oak.

6. Natural Regeneration – Local Scale
The rate of regeneration both in space and time depend on
changes on:
1) Macroclimate (temperature, precipitation, aridity).
2) Disturbance (past land-uses; .crops, grazing, fire).
3) Seed Dispersion.
4) Microclimate (topography).
Microclimate
Microclimate Integrates driven by
changes in: topography
1) PAR North
2) Temperature South +Humid
+Dry Environment Environment
3) Soil water
4) Wind
5) precipitation
The effect of microclimate is expected to be more important in DryLands

7. What´s New? – The Use of PSR
Potential Solar Radiation PSR
average of 2011
Low
PSR
High
PSR
Our sampling design had 4 different sites. At each one we covered as much as possible the 6
classes of PSR resulting in a total of 48 polygons. Which were observed over time.

8. What´s New? – The long-term monitoring
1943
We have a time
1943 series of 67 years
1947
1947
1958
1958 1969
… through 1958
photointerpretation … 1984
1995
2005
…we estimated the percentage
of Holm oak cover along the 2010
microclimatic gradient after
agricultural abandonment.

9. Natural regeneration along the microclimate
gradient
90 40 to 60 years
80 of natural regeneration
Holm oak cover (%)
70
60
50
40
30
20
10
0
10 20 30 40 50 60
January PSR (kWh/m2)
These results could be explained:
1) by facilitation processes along the natural regeneration;
2) By the negative effect of microclimate on the natural
regeneration of holm oak trees

10. Rate of Natural Regeneration of Quercus Ilex at Herdade da Contenda, limited by microclimate
South North

11. Building a model
Variables that might be important in the natural
regeneration of the Holm Oak trees
Variables
Altitude (m)
Slope (º)
ModA ModB ModC
PSR 12 months (Wh/m2)
Intercept -4.800 ± 3.042 6.238 ± 1.156*** 1.681 ± 0.288***
Amplitude of PSR (Wh/m2) PA 0.471 ± 0.100*** 0.081 ± 0.006*** 0.072 ± 0.006***
PSR of January (Wh/m2) PSR1 -8x10-5 ± 0.6x10-5*** -8x10-5 ± 0.6x10-5*** -8x10-5 ± 0.6x10-5***
RSD 0.036 ± 0.018+ -0.030 ± 0.007***
Tree cover before agriculture abandonment (%)
PA x RSD -0.002 ± 0.001***
Tree cover before agriculture abandonment in a 30
R2 0.72 0.69 0.66
m buffer (%)
AIC 421.5 433.9 447.5
Standard deviation of the precipitation since the
abandonment (mm) Ten-fold Cross validation give an error of
Years of Abandonment less than 10%
Modelling through GLMs Applying this model to a new area to test it

12. Validating the Model
The cost of this mistake was
28000€x2
1995
- PSR
Holm oak natural regeneration is
faster in the NW
Holm oak natural regeneration is + PSR
Holm oak
cover(%)
Holm oak cover (%)
much more slower in the SE
0,4 - 5
5 - 10
10 - 20
20 - 40
40 - 83 2010
Holm oak natural regeneration is
faster in the NW
Holm oak natural regeneration is
much more slower in the SE
25 years 40 years 50 years 60 years

13. Final Remarks
• This model have a high potential to enhance the reforestation
planning;
• It is a easy model to predict the potential of natural regeneration,
with advantage to be continuum in the space and at local scale;
• Potential to be applied in a climate change scenario.

14. ESSEM COST Action ES1104
Earth System Science and Environmental Management (ESSEM)
Arid Lands Restoration and Combat of Desertification:
Setting Up a Drylands and Desert Restoration Hub
WG3 - Plants, Ecology and Microclimate Manipulation
for Enhanced Vegetation Establishment

15. The ecosystem and
plants point of view

16. The main objective of the cost
To assemble a multidisciplinary network
of European and world experts
concentrating on arid lands restoration
and combat of desertification through
the establishment and management of
vegetation.

17. Restoration in Drylands
Objectives
Common in dryland environments:
Enhance
• High spatial heterogeneity vegetation
cover, establishme
• High temporal variability nt and optimize
management
Common Results Increase
Ecosystem Goods
• Not every plant grows and Services
• High mortality
Level:
• It is slow •Ecosystem
•Habitat
• Unpredictability trajectory •Plant

18. Objectives
• Review the state of the art in Europe and
compare it with the one in other continents;
• Interdisciplinary exchange between
theoretical knowledge, technical know-how
and traditional knowledge.

19. • Como se fez
Thank You