TY - JOUR
T1 - Factors affecting forest dynamics in the Iberian Peninsula from 1987 to 2012. The role of topography and drought
AU - José Vidal-Macua, Juan
AU - Ninyerola, Miquel
AU - Zabala, Alaitz
AU - Domingo-Marimon, Cristina
AU - Pons, Xavier
N1 - Publisher Copyright:
© 2017 The Authors
PY - 2017/12/15
Y1 - 2017/12/15
N2 - In southern Europe, climate trends are expected to be characterized by an increase in temperatures and less water availability. Analyzing the role of structural factors and the influence of a changing climate provides insights into the evolution of forest ecosystems in regions with similar environmental conditions. The Mediterranean fringe of the Iberian Peninsula is of particular interest due to its diverse topo climatic conditions and the increase in drought episodes during the last decades. This work studies forest dynamics in large areas of this geographical region by analyzing nine forest transitions. Vegetation covers were classified from three Landsat scenes for the period 1987–2012, and sub-periods 1987–2002 and 2002–2012. Conditions were described by topography derived variables, human factors and drought-occurrence variables. Boosted regression trees were used to identify the most important variables and describe the relationships between the forest dynamics and key factors. Variables such as solar radiation, topographic wetness index and tolerance to drought have been shown to be key factors in forest succession and when comparisons are made between vegetation groups. Main findings: The transition rate to Mediterranean and sub-Mediterranean broadleaf forests has increased during the analyzed period, while the transition rate to coniferous forests has decreased; Transitions to Mediterranean and sub-Mediterranean broadleaf forests are positively associated with drought occurrence while transitions to conifers are negatively affected by drought; Transitions from shrublands to forest stages are more vulnerable to factors controlling water availability; Important interactions between topography derived variables and drought have been found. The study provides robust evidence that drought occurrence plays an important role in the decline of conifers and the expansion of broadleaves, which could become the dominant species in many areas of the Mediterranean if climate model forecasts are met.
AB - In southern Europe, climate trends are expected to be characterized by an increase in temperatures and less water availability. Analyzing the role of structural factors and the influence of a changing climate provides insights into the evolution of forest ecosystems in regions with similar environmental conditions. The Mediterranean fringe of the Iberian Peninsula is of particular interest due to its diverse topo climatic conditions and the increase in drought episodes during the last decades. This work studies forest dynamics in large areas of this geographical region by analyzing nine forest transitions. Vegetation covers were classified from three Landsat scenes for the period 1987–2012, and sub-periods 1987–2002 and 2002–2012. Conditions were described by topography derived variables, human factors and drought-occurrence variables. Boosted regression trees were used to identify the most important variables and describe the relationships between the forest dynamics and key factors. Variables such as solar radiation, topographic wetness index and tolerance to drought have been shown to be key factors in forest succession and when comparisons are made between vegetation groups. Main findings: The transition rate to Mediterranean and sub-Mediterranean broadleaf forests has increased during the analyzed period, while the transition rate to coniferous forests has decreased; Transitions to Mediterranean and sub-Mediterranean broadleaf forests are positively associated with drought occurrence while transitions to conifers are negatively affected by drought; Transitions from shrublands to forest stages are more vulnerable to factors controlling water availability; Important interactions between topography derived variables and drought have been found. The study provides robust evidence that drought occurrence plays an important role in the decline of conifers and the expansion of broadleaves, which could become the dominant species in many areas of the Mediterranean if climate model forecasts are met.
KW - Boosted regression trees
KW - Broadleaf deciduous species
KW - Broadleaf evergreen species
KW - Conifer species
KW - Driving factors
KW - Drought
KW - Ecological succession
KW - Forest dynamics
KW - Forest shifts
KW - Iberian Peninsula
UR - http://www.scopus.com/inward/record.url?scp=85031713877&partnerID=8YFLogxK
U2 - 10.1016/j.foreco.2017.10.011
DO - 10.1016/j.foreco.2017.10.011
M3 - Article
SN - 0378-1127
VL - 406
SP - 290
EP - 306
JO - Forest Ecology and Management
JF - Forest Ecology and Management
ER -