Changes in landscape fire-hazard during the second half of the 20th century: Agriculture abandonment and the changing role of driving factors
Introduction
Fire activity has increased markedly during the second half of the last century in many parts of the world (FAO, 2001, Bowman et al., 2009). Fires are mainly driven by climate, fuels, availability of ignitions and, in some countries, firefighting capacity. While changes in climate (Westerling et al., 2006, Koutsias et al., 2012) and urban encroachment (Syphard et al., 2007, Syphard et al., 2012, Lampin-Maillet et al., 2011) have been proposed as major drivers of change in fire regime in some areas, changes in fuels and landscape-level fire-hazard might have also played a dominant role (Fernandez-Ales et al., 1992, Lepart and Debussche, 1992, Moreira et al., 2001, Kalabokidis et al., 2007, Carmel et al., 2009). In the case of Mediterranean countries of southern Europe, fires started to increase during the early 1970’s, but not so much in Northern Africa, indicating that socioeconomic factors were a major driver of change. More so, trends in fire activity in various countries was decoupled from changes in climate (San-Miguel-Ayanz et al., 2012), which further supports that socioeconomic changes, including changes in fuels and landscapes (Moreno et al., 1998, Rego, 1992), and also firefighting capacity in recent times (Brotons et al., 2013), were behind it, although additional effects of changes in climate cannot be excluded (Koutsias et al., 2013, Bedia et al., 2014). Recent studies indicate that trends in fire activity in some of the southern European countries have discontinuities that suggest a role for various factors, including land-use and land-cover (LULC) changes (Moreno et al., 2014).
In spite of LULC changes being widely recognized as driving factors of changes in fire, a quantification of this process, including the factors driving them, is yet poorly known. Moreover, considering the ever dynamic nature of the factors affecting fires, an assessment of the variable role that the different factors play through time in affecting landscape fire-hazard is lacking. Nowadays, the validity of the stationary role of environmental and socioeconomic factors in explaining LULC changes, mainly agriculture abandonment, has been questioned (Hatna and Bakker, 2011, Bakker and Veldkamp, 2012); suggesting that relationships between croplands and environmental conditions (Bakker and Veldkamp, 2012) as well as the role of socio-economic factors (Kuemmerle et al., 2008, Müller and Munroe, 2008, Baumann et al., 2011) have changed during last decades. This is important because socioeconomics and their effects on the landscape continue changing. Anticipating how these factors vary through time to affect landscape level fire-hazard is important to project future changes in fire regime, notably in a context of changing climate, land-use patterns and life styles.
Moreover, establishing cause–effect relationships between explanatory factors and LULC changes have also proven difficult (Irwin and Geoghegan, 2001, Nelson, 2001) mainly due to: (i) the patterns of LULC changes are spatially heterogeneous and location specific (vary spatially from one region to another, being anisotropic), (ii) LULC changes have a clear hierarchical spatial structure being scale-sensitive (i.e., the probability of LULC change depends on factors operating at different scales), and (iii) the role of driving factors are spatially heterogeneous (Koutsias et al., 2010) and temporally non-stationary (Bakker and Veldkamp, 2012). In spite of these limitations, the most common statistical approach for explaining LULC changes has been based on general linear model (GLM), such as logistic or multinomial regression, which assume independence of observations and relate LULC changes with explanatory factors acting at different scales obscuring patterns and processes across scales (e.g., Serneels and Lambin, 2001, Bakker et al., 2005, Améztegui et al., 2010). Multilevel modeling or general linear mixed models (GLMM) can include explicitly spatial structures as municipalities or other spatial divisions, thus allowing studying the effects of different spatial scales on a particular response variable, while providing a robust estimation of error (Snijders and Bosker, 1999, Diez-Roux, 2000). Apart from providing better statistical inference by modeling excess heterogeneity present in the data, GLMM address spatially misaligned explanatory variables and spatial structure in the ecological pattern. Recently, several works have used GLMMs to develop explanatory models on land-use patterns and changes around the world (Pan et al., 2004, Neumann et al., 2011, López-Carr et al., 2012). In the case of models of agriculture abandonment in Mediterranean rural areas the standard GLMs (logistic and/or multinomial) have been used (Van Doorn and Bakker, 2007, Millington et al., 2008); or only descriptive analyses about the relationship between agricultural abandonment and driving factors have been carried out (Moreira et al., 2001, Romero-Calcerrada and Perry, 2004). No study has approached agriculture abandonment in this region of the world based on robust approaches such as GLMMs. This is important for understanding causal factors in the modification of a landscape highly reactive to fire.
Here we studied that the main LULC changes occurred from 1950s to 2000 by three distinctive periods (1950s–1978; 1978–1986 and 1986–2000), in a large rural area in Central-Western Spain, focusing on changes leading to shifts in fire-hazard. For this purpose, we focused on the contribution of agriculture abandonment to such changes. Furthermore, we modeled agriculture abandonment using GLMMs based on environmental and socio-economic factors at each time-step to detect possible changes in drivers through time. Finally, we developed spatially-explicit maps of agriculture abandonment from GLMMs and tested their predictive capacity. The hypotheses to be tested were: (a) early abandonments were driven by local constraints due to low economic development, but late abandonments would be driven by non-local factors due to the effects of globalization process; consequently, (b) drivers of land abandonment leading to change in fire-hazard were not constant over time, varying in their relative role with time.
Section snippets
Study area
The study area is in Central-Western Spain; UTM coordinates 4369–4551 and 201–394 in the zone 30 North, covering 56,000–km2 (Fig. 1A). The area is characterized by the mountainous landscapes of Sierra de Gredos, running across the northern half of the area, flanked by relatively flat areas towards the North and South (Fig. 1B–C). The climate is mild and relatively wet in the flat areas and cold and very wet in upper mountains (Fig. 1D). Soils in the mountain areas are shallow, with high
General LULC trends
From 1950s to 2000 there was a continuous decrease of the non-hazardous LULC types (Fig. 3A). Croplands were the ones that lost a larger extension (−13%), followed, at a distance, by deciduous forests (−4%) and agroforestry areas (c.a. −2%) (Fig. 3A). In relation to non-hazardous LULC changes, agriculture conversion was maximum during the first period and decreased sharply in the latter period; afforestation with non-hazardous species and densification to deciduous forests was reduced (<5%) and
LULC and socio-economic changes from 1950s to 2000: implications for fire-hazard
We have shown that landscape fire-hazard continuously increased from 1950s to 2000 due to hazardous LULC changes and stability of hazardous LULCs, both of which tended to occupy greater extension over time. The most important hazardous LULC changes during the entire period were agriculture abandonment and deforestation, the former being dominant until 1986 (pre-1990 period) and the latter thereafter. The intense agriculture abandonment of marginal areas and the concentration of agriculture in
Conclusions
We have shown that the main LULC changes occurred from 1950s to 2000 globally increased fire-hazard in the study area. During the pre-1990 period, agriculture abandonment occurred in mosaic mountain rural areas, with high proportion of wildland vegetation, that were also affected by other hazardous changes (deforestation, afforestation and densification), increasing sharply the landscape fire-hazard. During the post-1990 period, deforestation by forest fires dominated over agriculture
Acknowledgements
The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007–2013), Project FUME, grant agreement no. 243888. We acknowledge the estimated help of Carmen Arroyo in digitizing old LULC maps and I.R. Urbieta for her fruitful comments.
References (77)
- et al.
Soil erosion as a driver of land-use change
Agric. Ecosyst. Environ.
(2005) - et al.
The forest transition: towards a more comprehensive theoretical framework
Land Use Policy
(2010) - et al.
Patterns and drivers of post-socialist farm agriculture abandonment in Western Ukraine
Land Use Policy
(2011) Future European agricultural landscapes—What can we learn from existing quantitative land use scenario studies?
Agric. Ecosyst. Environ.
(2006)- et al.
Assessing fire risk using Monte Carlo simulations of fire spread
For. Ecol. Manage.
(2009) - et al.
Multi-scale assessment and spatial modelling of agriculture abandonment in a European peripheral region: Galicia (Spain), 1956–2004
Land Use Policy
(2012) - et al.
Agricultural land abandonment and natural forest re-growth in the Swiss mountains: a spatially explicit economic analysis
Agric. Ecosyst. Environ.
(2007) - et al.
Modeling tropical deforestation in the southern Yucatán peninsular region: comparing survey and satellite data
Agric. Ecosyst. Environ.
(2001) - et al.
Theory, data, methods: developing spatially explicit economic models of land use change
Agric. Ecosyst. Environ.
(2001) - et al.
Where did the fires burn in Peloponnisos, Greece the summer of 2007? Evidence for a synergy of fuel and weather
Agric. For. Meteorol.
(2012)
The causes of land-use and land-cover change: moving beyond the myths
Global Environ. Change.
Land cover analysis in wildland-urban interfaces according to wildfire risk: a case study in the South of France
For. Ecol. Manage.
Space versus place in complex human-natural systems: spatial and multi-level models of tropical land use and cover change (LUCC) in Guatemala
Ecol. Model
Agricultural abandonment in mountain areas of Europe: environmental consequences and policy response
J. Environ. Manage.
Are Pinus halepensis plantations useful as a restoration tool in semiarid Mediterranean areas?
For. Ecol. Manage.
Human-caused wildfire risk rating for prevention planning in Spain
J. Environ. Manage.
The vulnerability of ecosystem services to land use change
Agric. Ecosyst. Environ.
Landscape–wildfire interactions in southern Europe: implications for landscape management
J. Environ. Manage.
Fire regime changes and major driving forces in Spain from 1968 to 2010
Environ. Sci. Policy
The dynamics of land cover change in western Honduras: exploring spatial and temporal complexity
Agric. Econ.
Analysing data across geographic scales in Honduras: detecting levels of organisation within systems
Agric. Ecosyst. Environ.
Exploring global irrigation patterns: a multilevel modelling approach
Agric. Syst.
Multilevel modelling of land use from field to village level in the Philippines
Agric. Syst.
Farm-level models of spatial patterns of land use and land cover dynamics in the Ecuadorian Amazon
Agric. Ecosyst. Environ.
The role of agriculture abandonment in landscape dynamics in the SPA ‘Encinares del rio Alberche y Cofio, Central Spain, 1984-1999
Landscape Urban Plan
Relationship between landscape typology and socioeconomic structure
Ecol. Model
Proximate causes of land-use change in Narok District, Kenya: a spatial statistical model
Agric. Ecosyst. Environ.
Marginal lands in Europe: causes of decline
Basic Appl. Ecol.
Land-use changes as major drivers of mountain pine (Pinus uncinata Ram.) expansion in the Pyrenees
Global Ecol. Biogeogr.
Changing relationships between land use and environmental characteristics and their consequences for spatially explicit land-use change prediction
J. Land Use Sci.
Forest fire danger projections in the Mediterranean using ENSEMBLES regional climate change scenarios
Clim. Change
CORINE Land Cover Technical Guide: Addendum 2000
Fire in the earth system
Science
How fire history, fire suppression practices and climate change affect wildfire regimes in Mediterranean landscapes
PLoS One
Driving forces of landscape change – current and new directions
Landscape Ecol.
Mapa Forestal de España escala 1:400000
The Development of Modern Spain: an Economic History of the Nineteenth and Twentieth Centuries
Cited by (89)
Private forest owners' organizations adherence to policy tools. Insights from Portugal
2024, Forest Policy and EconomicsWildfire exposure and risk in pulp paper companies’ plantations under extreme weather conditions: A case study in North-Western Portugal
2024, International Journal of Disaster Risk ReductionActive governance of agro-pastoral, forest and protected areas mitigates wildfire impacts in Italy
2023, Science of the Total EnvironmentAssessing public preferences for a wildfire mitigation policy in Crete, Greece
2023, Forest Policy and EconomicsSoil biogeochemistry and microbial community dynamics in Pinus pinaster Ait. forests subjected to increased fire frequency
2023, Science of the Total EnvironmentEvaluating priority locations and potential benefits for building a nation-wide fuel break network in Portugal
2022, Journal of Environmental Management
- 1
Current address: Department of Earth Sciences and Construction, Universidad de las Fuerzas Armadas – ESPE (UFA-ESPE), Campus Politécnico, Av. Gral. Rumiñahui s/n, P.O. Box 171-5-231B, Sangolquí – Ecuador.