scholarly journals Spatial and temporal patterns of plant functional types under simulated fire regimes

2007 ◽  
Vol 16 (4) ◽  
pp. 484 ◽  
Author(s):  
Juli G. Pausas ◽  
F. Lloret
Keyword(s):  
Spatial Distribution ◽  
Fire Regime ◽  
Fire Regimes ◽  
Plant Functional Types ◽  
Spatial And Temporal Patterns ◽  
Spatial And Temporal Scales ◽  
Fire Recurrence ◽  
Functional Types ◽  
Mediterranean Countries ◽  
Fire Scenarios

In spite of enormous fire suppression advances in Mediterranean countries, large high-intensity fires are still common. The effects on vegetation structure and composition of fire and fire regime changes at large spatial and temporal scales are poorly known, and landscape simulation models may throw some light in this regard. Thus, we studied how the abundance, richness, and spatial distribution of the different plant types are sensitive to the frequency, extent and spatial distribution of wildfires, using a landscape simulation model (FATELAND). We simulated the dynamics of 10 plant functional types (PFTs) defined as combinations of post-fire persistence strategies and life forms, under the following fire scenarios: No Fire, Suppressed (one large fire every 20 years), Prescribed (small fuel reductions every year), Unmanaged-1 (two small fires every year) and Unmanaged-2 (four small fires every year). The results suggest that the different fire regimes generate different spatial fire-recurrence patterns and changes in the proportion of the dominant species. For instance, with increasing fire recurrence, seeder shrubs (i.e. those recruiting new individuals after fire from persisting seed bank) with early reproduction increased and seeder trees decreased, while little variation was found for resprouters. Fire also increased the spatial aggregation of plants, while PFT richness decreased with increasing fire recurrence. The results suggest patterns of changes similar to those reported in field studies, and thus they provide consistent hypotheses on the possible vegetation changes due to different fire scenarios.

Spatial Distribution of Roots across Three Dryland Ecosystems and Plant Functional Types

2019 ◽  
Vol 79 (2) ◽  
pp. 159 ◽  
Author(s):  
Jessica G. Swindon ◽  
William K. Lauenroth ◽  
Daniel R. Schlaepfer ◽  
Ingrid C. Burke
Keyword(s):  
Spatial Distribution ◽  
Plant Functional Types ◽  
Functional Types ◽  
Dryland Ecosystems ◽  
Distribution Of Roots

scholarly journals Competition between plant functional types in the Canadian Terrestrial Ecosystem Model (CTEM) v. 2.0

2016 ◽  
Vol 9 (1) ◽  
pp. 323-361 ◽  
Author(s):  
J. R. Melton ◽  
V. K. Arora
Keyword(s):  
Spatial Distribution ◽  
Large Scale ◽  
Terrestrial Ecosystem ◽  
Ecosystem Model ◽  
Plant Functional Types ◽  
Atmospheric Composition ◽  
Climate Modelling ◽  
Fractional Coverage ◽  
Terrestrial Ecosystem Model ◽  
Functional Types

Abstract. The Canadian Terrestrial Ecosystem Model (CTEM) is the interactive vegetation component in the Earth system model of the Canadian Centre for Climate Modelling and Analysis. CTEM models land–atmosphere exchange of CO2 through the response of carbon in living vegetation, and dead litter and soil pools, to changes in weather and climate at timescales of days to centuries. Version 1.0 of CTEM uses prescribed fractional coverage of plant functional types (PFTs) although, in reality, vegetation cover continually adapts to changes in climate, atmospheric composition and anthropogenic forcing. Changes in the spatial distribution of vegetation occur on timescales of years to centuries as vegetation distributions inherently have inertia. Here, we present version 2.0 of CTEM, which includes a representation of competition between PFTs based on a modified version of the Lotka–Volterra (L–V) predator–prey equations. Our approach is used to dynamically simulate the fractional coverage of CTEM's seven natural, non-crop PFTs, which are then compared with available observation-based estimates. Results from CTEM v. 2.0 show the model is able to represent the broad spatial distributions of its seven PFTs at the global scale. However, differences remain between modelled and observation-based fractional coverage of PFTs since representing the multitude of plant species globally, with just seven non-crop PFTs, only captures the large-scale climatic controls on PFT distributions. As expected, PFTs that exist in climate niches are difficult to represent either due to the coarse spatial resolution of the model, and the corresponding driving climate, or the limited number of PFTs used. We also simulate the fractional coverage of PFTs using unmodified L–V equations to illustrate its limitations. The geographic and zonal distributions of primary terrestrial carbon pools and fluxes from the versions of CTEM that use prescribed and dynamically simulated fractional coverage of PFTs compare reasonably well with each other and observation-based estimates. The parametrization of competition between PFTs in CTEM v. 2.0 based on the modified L–V equations behaves in a reasonably realistic manner and yields a tool with which to investigate the changes in spatial distribution of vegetation in response to future changes in climate.

scholarly journals Landscape-based fire scenarios and fire types in the Ayllón massif (Central Mountain Range, Spain), 19th and 20th centuries

2020 ◽  
Vol 46 (1) ◽  
pp. 103-126
Author(s):  
C.R. Sequeira ◽  
C. Montiel-Molina ◽  
F.C. Rego
Keyword(s):  
Forest Management ◽  
Fire History ◽  
Driving Forces ◽  
Fire Regime ◽  
Fire Regimes ◽  
Landscape Dynamics ◽  
Mountain Range ◽  
Regime Changes ◽  
Fire Scenarios ◽  
Fire Type

Wildfires have been a major landscape disturbance factor throughout history in inland mountain areas of Spain. This paper aims to understand the interaction of fire regimes and landscape dynamics during the last two centuries within a socio-spatial context. The study area selected for this historical and spatial analysis is the Ayllón massif, in the Central Mountain Range. The theoretical background used to identify the driving forces of fire regime changes over the 19th and 20th centuries in this mountain area includes landscape-based fire scenarios and fire-type concepts. Both concepts have been addressed in recent studies from a spatial planning and fire management approach in an attempt to understand current fire landscapes and wildfire risk. However, this is the first time that these concepts have been applied to show that both spatial and temporal scales are crucial for an understanding of the current wildfire panorama, and that fire history related to landscape dynamics is fundamental in socio-spatial differences in fire regimes.Four variables (fire history, land use, population and settlement system, and forest management) were assessed to define historical landscape-based fire scenarios, and three fire feature variables (fire extent, fire cause, and spatial distribution pattern) were considered to define historical fire-types. We found that the non-linear evolution of fire regimes during the 19th and 20th centuries was determined by fire-type changes according to landscape dynamics. Moreover, population and forest management have been the main driving forces of fire regime tipping points or pyrotransitions. This study validates the hypothesis that fire regime changes are the result of the interaction of fire history and landscape dynamics.

scholarly journals A global scale mechanistic model of photosynthetic capacity (LUNA V1.0)

2016 ◽  
Vol 9 (2) ◽  
pp. 587-606 ◽  
Author(s):  
A. A. Ali ◽  
C. Xu ◽  
A. Rogers ◽  
R. A. Fisher ◽  
S. D. Wullschleger ◽  
...  
Keyword(s):  
Electron Transport ◽  
Environmental Conditions ◽  
Photosynthetic Capacity ◽  
Mechanistic Model ◽  
Global Scale ◽  
Plant Functional Types ◽  
Spatial And Temporal Patterns ◽  
Climate Conditions ◽  
Functional Types ◽  
Light Capture

Abstract. Although plant photosynthetic capacity as determined by the maximum carboxylation rate (i.e., Vc, max25) and the maximum electron transport rate (i.e., Jmax25) at a reference temperature (generally 25 °C) is known to vary considerably in space and time in response to environmental conditions, it is typically parameterized in Earth system models (ESMs) with tabulated values associated with plant functional types. In this study, we have developed a mechanistic model of leaf utilization of nitrogen for assimilation (LUNA) to predict photosynthetic capacity at the global scale under different environmental conditions. We adopt an optimality hypothesis to nitrogen allocation among light capture, electron transport, carboxylation and respiration. The LUNA model is able to reasonably capture the measured spatial and temporal patterns of photosynthetic capacity as it explains  ∼  55 % of the global variation in observed values of Vc, max25 and  ∼  65 % of the variation in the observed values of Jmax25. Model simulations with LUNA under current and future climate conditions demonstrate that modeled values of Vc, max25 are most affected in high-latitude regions under future climates. ESMs that relate the values of Vc, max25 or Jmax25 to plant functional types only are likely to substantially overestimate future global photosynthesis.

scholarly journals Plant-driven variation in decomposition rates improves projections of global litter stock distribution

2011 ◽  
Vol 8 (4) ◽  
pp. 8817-8844 ◽  
Author(s):  
V. Brovkin ◽  
P. M. van Bodegom ◽  
T. Kleinen ◽  
C. Wirth ◽  
W. Cornwell ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Boreal Forests ◽  
Fire Regimes ◽  
Plant Litter ◽  
Plant Functional Types ◽  
Atmospheric Co2 ◽  
Strong Increase ◽  
Decomposition Rates ◽  
Global Databases ◽  
Functional Types

Abstract. Plant litter stocks are critical, regionally for their role in fueling fire regimes and controlling soil fertility, and globally through their feedback to atmospheric CO2 and climate. Here we employ two global databases linking plant functional types to decomposition rates of wood and leaf litter (Cornwell et al., 2008; Weedon et al., 2009) to improve future projections of climate and carbon cycle using an intermediate complexity Earth system model. Implementing separate wood and leaf litter decomposabilities and their temperature sensitivities for a range of plant functional types yielded a more realistic distribution of litter stocks in all present biomes with except of boreal forests and projects a strong increase in global litter stocks and a concomitant small decrease in atmospheric CO2 by the end of this century. Despite a relatively strong increase in litter stocks, the modified parameterization results in less elevated wildfire emissions because of litter redistribution towards more humid regions.

scholarly journals Competition between plant functional types in the Canadian Terrestrial Ecosystem Model (CTEM) v. 2.0

2015 ◽  
Vol 8 (6) ◽  
pp. 4851-4948 ◽  
Author(s):  
J. R. Melton ◽  
V. K. Arora
Keyword(s):  
Spatial Distribution ◽  
Large Scale ◽  
Terrestrial Ecosystem ◽  
Ecosystem Model ◽  
Plant Functional Types ◽  
Atmospheric Composition ◽  
Climate Modelling ◽  
Fractional Coverage ◽  
Terrestrial Ecosystem Model ◽  
Functional Types

Abstract. The Canadian Terrestrial Ecosystem Model (CTEM) is the interactive vegetation component in the Earth system model of the Canadian Centre for Climate Modelling and Analysis. CTEM models land–atmosphere exchange of CO2 through the response of carbon in living vegetation, and dead litter and soil pools, to changes in weather and climate at timescales of days to centuries. Version 1.0 of CTEM uses prescribed fractional coverage of plant functional types (PFTs) although, in reality, vegetation cover continually adapts to changes in climate, atmospheric composition, and anthropogenic forcing. Changes in the spatial distribution of vegetation occur on timescales of years to centuries as vegetation distributions inherently have inertia. Here, we present version 2.0 of CTEM which includes a representation of competition between PFTs based on a modified version of the Lotka–Volterra (L–V) predator–prey equations. Our approach is used to dynamically simulate the fractional coverage of CTEM's seven natural, non-crop PFTs which are then compared with available observation-based estimates. Results from CTEM v. 2.0 show the model is able to represent the broad spatial distributions of its seven PFTs at the global scale. However, differences remain between modelled and observation-based fractional coverages of PFTs since representing the multitude of plant species globally, with just seven non-crop PFTs, only captures the large scale climatic controls on PFT distributions. As expected, PFTs that exist in climate niches are difficult to represent either due to the coarse spatial resolution of the model, and the corresponding driving climate, or the limited number of PFTs used. We also simulate the fractional coverages of PFTs using unmodified L–V equations to illustrate its limitations. The geographic and zonal distributions of primary terrestrial carbon pools and fluxes from the versions of CTEM that use prescribed and dynamically simulated fractional coverage of PFTs compare reasonably well with each other and observation-based estimates. The parametrization of competition between PFTs in CTEM v. 2.0 based on the modified L–V equations behaves in a reasonably realistic manner and yields a tool with which to investigate the changes in spatial distribution of vegetation in response to future changes in climate.

Repeated disturbance through chaining and burning differentially affects recruitment among plant functional types in fire-prone heathlands

2010 ◽  
Vol 19 (1) ◽  
pp. 52 ◽  
Author(s):  
Carl R. Gosper ◽  
Suzanne M. Prober ◽  
Colin J. Yates
Keyword(s):  
Fire Management ◽  
Fire Regimes ◽  
Agricultural Landscapes ◽  
Plant Functional Types ◽  
Vegetation Composition ◽  
Management Planning ◽  
Functional Types ◽  
Disturbance Response ◽  
A Chain ◽  
In Fire

Managing fire regimes is increasingly recognised as important for biodiversity conservation in fragmented agricultural landscapes in fire-prone regions. In the global biodiversity hotspot of south-west Western Australia, chaining and burning is a novel technique for facilitating fire management. Vegetation is first dislodged using a chain, then after a period of curing, burnt. The effects on plant communities are largely unstudied, despite the potential consequences of combining two disturbance events. We hypothesised that outcomes would vary depending on plant functional types defined by disturbance response. We compared plant community composition and recruitment and resprouting of plant functional types in mallee-heath subject to chaining and burning, burning only and neither of these. The effects of chaining and burning did not differ from only burning at the community level. Importantly, however, we recorded 90% fewer recruits of serotinous, obligate seeders in chained and burnt compared with only burnt plots, and a 44% decrease in their species richness. By contrast, recruits of obligate seeding shrubs and fire-ephemeral herbs with persistent soil-stored seed banks increased by 166% in chained and burnt plots. Sprouters showed little difference. We conclude that chaining and burning is likely to significantly alter vegetation composition, and potentially poses a significant threat to serotinous, obligate seeders. These impacts require consideration in fire management planning.

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