Rossini et al. (2025) Wildfires In Xerophytic Shrublands of Lihué Calel National Park, La Pampa, Argentina: A Temporal Analysis Based on Climatic and Spectral Indices

Identification

• Journal: Cuadernos de Investigación Geográfica
• Year: 2025
• Date: 2025-09-30
• Authors: María Sol Rossini, Carla Etel Suárez
• DOI: 10.18172/cig.6611

Research Groups

• National Scientific and Technical Research Council (CONICET), Argentina
• National Parks Administration (APN), Argentina
• Laboratory of Ecology in Semiarid Environments (LEAS), Faculty of Agronomy, National University of La Pampa, Argentina

Short Summary

This study analyzed climatic and spectral indices over 29 years (1995–2023) to understand the fire regime in xerophytic shrublands of Lihué Calel National Park, Argentina. It found that wet periods followed by dry periods, coupled with increasing temperatures and precipitation, are associated with wildfire events, suggesting a future with heightened fire frequency in these ecosystems.

Objective

• To analyze variations in climatic (Standardised Precipitation and Evapotranspiration Index - SPEI) and spectral (Normalised Difference Vegetation Index - NDVI) indices over 29 years (1995–2023) to enhance understanding of the fire regime in xerophytic shrublands.
• To evaluate trends in climatic variables within the context of global climate change.

Study Configuration

• Spatial Scale: Lihué Calel National Park (32,514 hectares), La Pampa province, Argentina, within the Monte Ecoregion.
• Temporal Scale: 29-year period (1995–2023) for climatic and wildfire data; 23-year time series (starting 2000) for NDVI data.

Methodology and Data

• Models used:
  • Standardised Precipitation and Evapotranspiration Index (SPEI) at 3, 6, 12, and 24-month timescales.
  • Normalised Difference Vegetation Index (NDVI).
  • Theil-Sen estimator for trend detection.
  • Non-parametric Mann-Kendall test for trend significance.
  • Segmented regression for linear inflexion points.
  • Pearson's correlation coefficient.
  • Seasonal Autoregressive Integrated Moving Average (SARIMA) models for seasonal modeling and cross-correlation.
  • Augmented Dickey-Fuller (ADF) test for stationarity.
  • Ljung-Box test for residual autocorrelation.
  • Shapiro-Wilk test for data normality.
• Data sources:
  • Lihué Calel National Park (LCNP) Automated Meteorological Station: Monthly averages for precipitation, minimum temperature, maximum temperature, and mean temperature (1995–2023).
  • LCNP Fire Management Plan (APN, 2021): Records of burned area size (1995–2023).
  • SATVeg database (Embrapa Digital Agriculture): Monthly NDVI data for shrubs (NDVIs) and grasslands (NDVIg) (2000–2023), derived from MODIS sensor (NASA's Terra mission) with 16-day temporal and 250 meter spatial resolution.

Main Results

• Precipitation, mean temperature, and maximum temperature showed positive and significant trends over the study period, with increases of 7.51 mm per year, 0.04285 °C per year, and 0.048 °C per year, respectively.
• The mean precipitation over the study period was 433 mm.
• SPEI-6, SPEI-12, and SPEI-24 exhibited positive and significant linear trends, indicating a shift towards wetter conditions over longer timescales.
• SPEI-12 showed the highest correlation with large, severe fire events, with a significant negative correlation (r = -0.10, p = 0.0374) at lag 0 with annual burned area.
• Shrubland NDVI (NDVIs) had the strongest positive correlation with SPEI-24 (r = 0.68, p < 0.0002), indicating a long-term response to cumulative moisture.
• Grassland NDVI (NDVIg) had the strongest positive correlation with SPEI-6 and SPEI-12 (r = 0.81 for both, p < 0.000001), reflecting a quicker response to shorter-term moisture signals.
• Major fire events were typically preceded by years of above-average precipitation, followed by below-average precipitation in the year of the fire, occurring at the beginning of or immediately after the summer season.

Contributions

• Provides a valuable methodological framework for understanding the pre-ignition context of wildfires by integrating climatic and spectral indices.
• Enhances the understanding of interrelationships between climate variables and their potential as predictors for future fires in xerophytic shrublands.
• Underscores the importance of combining multiscale climate indices (SPEI) with spectral vegetation indices (NDVI) to characterize drought-humidity cycles and their influence on vegetation dynamics and fuel accumulation.
• Supports the development of effective fire management and prevention strategies, including early warning systems, by identifying periods of phytomass accumulation and ignition thresholds.
• Offers potential tools to connect ecological research with land management strategies and public policies for wildfire prevention in semiarid regions, particularly in the context of climate change.

Funding

The authors acknowledge support from the technicians of the National Parks Administration of Lihué Calel National Park and the Faculty of Agronomy, National University of La Pampa. No specific funding projects or reference codes were listed.

Citation

@article{Rossini2025Wildfires,
  author = {Rossini, María Sol and Suárez, Carla Etel},
  title = {Wildfires In Xerophytic Shrublands of Lihué Calel National Park, La Pampa, Argentina: A Temporal Analysis Based on Climatic and Spectral Indices},
  journal = {Cuadernos de Investigación Geográfica},
  year = {2025},
  doi = {10.18172/cig.6611},
  url = {https://doi.org/10.18172/cig.6611}
}