scholarly journals Tropical Dry Forest Resilience to Fire Depends on Fire Frequency and Climate

2021 ◽  
Vol 4 ◽  
Author(s):  
Maximilian Hartung ◽  
Geovana Carreño-Rocabado ◽  
Marielos Peña-Claros ◽  
Masha T. van der Sande
Keyword(s):  
Tropical Forests ◽  
Tropical Dry Forest ◽  
Remote Sensing Data ◽  
Fire Frequency ◽  
Dry Forest ◽  
Fire Disturbance ◽  
Fire Intensity ◽  
Forest Resilience ◽  
Landsat Satellite ◽  
In Fire

Wildfires are becoming increasingly frequent and devastating in many tropical forests. Although seasonally dry tropical forests (SDTF) are among the most fire-threatened ecosystems, their long-term response to frequent wildfires remains largely unknown. This study is among the first to investigate the resilience in response to fire of the Chiquitano SDTF in Bolivia, a large ecoregion that has seen an unprecedented increase in fire intensity and frequency in recent years. We used remote sensing data to assess at a large regional and temporal scale (two decades) how fire frequency and environmental factors determine the resilience of the vegetation to fire disturbance. Resilience was measured as the resistance to fire damage and post-fire recovery. Both parameters were monitored for forested areas that burned once (F1), twice (F2), and three times (F3) between 2000 and 2010 and compared to unburned forests. Resistance and recovery were analyzed using time series of the Normalized Burn Ratio (NBR) index derived from Landsat satellite imagery, and climatic, topographic, and a human development-related variable used to evaluate their influence on resilience. The overall resilience was lowest in forests that burned twice and was higher in forests that burned three times, indicating a possible transition state in fire resilience, probably because forests become increasingly adapted during recurrent fires. Climatic variables, particularly rainfall, were most influential in determining resilience. Our results indicate that the Chiquitano dry forest is relatively resilient to recurring fires, has the capacity to recover and adapt, and that climatic differences are the main determinants of the spatial variation observed in resilience. Nevertheless, further research is needed to understand the effect of the higher frequency and intensity of fires expected in the future due to climate change and land use change, which may pose a greater threat to forest resilience.

scholarly journals Impulsive Fire Disturbance in a Savanna Model: Tree–Grass Coexistence States, Multiple Stable System States, and Resilience

2021 ◽  
Vol 83 (11) ◽  
Author(s):  
Alanna Hoyer-Leitzel ◽  
Sarah Iams
Keyword(s):  
Fire Frequency ◽  
Fire Disturbance ◽  
Fire Intensity ◽  
Ode Models ◽  
The Social ◽  
Impulsive Model ◽  
System States ◽  
Bifurcation Structures ◽  
In Fire ◽  
The Impact

AbstractSavanna ecosystems are shaped by the frequency and intensity of regular fires. We model savannas via an ordinary differential equation (ODE) encoding a one-sided inhibitory Lotka–Volterra interaction between trees and grass. By applying fire as a discrete disturbance, we create an impulsive dynamical system that allows us to identify the impact of variation in fire frequency and intensity. The model exhibits three different bistability regimes: between savanna and grassland; two savanna states; and savanna and woodland. The impulsive model reveals rich bifurcation structures in response to changes in fire intensity and frequency—structures that are largely invisible to analogous ODE models with continuous fire. In addition, by using the amount of grass as an example of a socially valued function of the system state, we examine the resilience of the social value to different disturbance regimes. We find that large transitions (“tipping”) in the valued quantity can be triggered by small changes in disturbance regime.

Fire resistance and bark properties of trees in a seasonally dry forest in eastern Bolivia

1997 ◽  
Vol 13 (5) ◽  
pp. 727-740 ◽  
Author(s):  
Michelle A. Pinard ◽  
Jean Huffman
Keyword(s):  
Specific Gravity ◽  
Moisture Content ◽  
Tree Species ◽  
Tropical Dry Forest ◽  
Fire Frequency ◽  
Dry Forest ◽  
Bark Thickness ◽  
Seasonally Dry ◽  
Low Intensity ◽  
In Fire

ABSTRACTAs forest fragmentation and intentional burning of grasslands increase, the frequency of fires penetrating the dry and subhumid tropical forests of Bolivia is also likely to increase. To expand our understanding of the role of fire in tropical dry forest, the physical and thermal properties of barks of tree species were studied to determine their relative resistances to cambial damage by fire. For 16 tree species found in the dry forest of the Lomerío region of eastern Bolivia, bark thickness, moisture content, and specific gravity were measured. Insulating capabilities of bark were measured by obtaining cambial and surface temperatures during experimental wick fires. Bark thickness on trees 5-100 cm dbh (diameter at 1.4 m) ranged from 2–51 mm and both thick- and thin-barked species were represented. For all species, bark thickness increased as stem diameter increased. Bark thickness explained more (63%) of the variation in peak cambial temperatures during fires than did bark moisture content (4%) or specific gravity (1%). A threshold bark thickness of 18 mm was associated with the ability to withstand lethal cambial temperatures during the experimental, low intensity fires. For 13 of the 16 species included in this study, trees ≤20 cm dbh have bark thickness below the threshold 18 mm and, therefore, are likely to experience cambial injury from low intensity fires. Our results suggest that the forest presently characteristic of the Lomerío region did not develop with frequent fires and that species composition is likely to be substantially affected by an increase in fire frequency.

scholarly journals Madrigueras de Liomys pictus en dos selvas tropicales del Pacífico mexicano.

2009 ◽  
Vol 13 (1) ◽  
pp. 63 ◽  
Author(s):  
Yolanda Domínguez-Castellanos ◽  
Beatriz Hernandez Meza ◽  
Angeles Mendoza D. ◽  
Gerardo Ceballos González
Keyword(s):  
Seed Production ◽  
Tropical Forests ◽  
Plant Species ◽  
Deciduous Forest ◽  
Vegetation Type ◽  
Tropical Dry Forest ◽  
Dry Forest ◽  
Mexican Pacific ◽  
La Selva

Resumen: Se determinó la estructura y el contenido de las madrigueras de Liomys pictus por tipo de vegetación y temporada del año, en dos selvas tropicales del Pacífico Mexicano. Se encontraron 24 madrigueras: en la selva baja la mayoría son complejas, mientras que  en la selva mediana son lineales, por consiguiente y de acuerdo a la clasificación de las madrigueras, en selva baja se presentaron madrigueras múltiples y en selva mediana madrigueras simples. De acuerdo al contenido, las de selva baja tienen en promedio una mayor cantidad de materiales en comparación a las de selva mediana. Se catalogaron un total de 248 especies de plantas de estas 50 se comparten en ambos sitios, del total de las especies se llegaron a identificar sólo 77. Las familias más representativas fueron Leguminoseae, Euphorbiaceae y Convolvulaceae. La estructura de las madrigueras no esta determinada por la temporalidad, sin embargo el contenido esta determinado con la cantidad de material almacenado aunque la producción de semillas esta definido por el patrón de fructificación que esta dado a lo largo del año.Palabras clave: Madrigueras, estructura, contenido, Liomys pictus, Jalisco, México.Abstract: We determined the structure and contents of burrows of Liomys pictus by vegetation type and season in two tropical forests of the Mexican Pacific. 24 burrows were found in the tropical dry forest and most complex, in the semi deciduous forest is linear, and therefore according to the classification of the burrows in the tropical dry forest are more numerous and simple in the semi deciduous forest. According to the content, of the tropical dry forest have on average a greater amount of material compared to the semi deciduous forest. Were categorized a total of 248 plant species of these 50 sites are shared in both the total number of species is to determine 77. The most representative families were Leguminoseae, Euphorbiaceae and Convulvolaceae. The structure of the burrows is not affected by the timing, but the content is determined with the amount of stored material but seed production is defined by the pattern of fruit that is given throughout the year.Key words: Burrows, structure, food hoarding, Liomys pictus, Jalisco, Mexico.

Fire effects on the spatial patterns of soil resources in a Nicaraguan wet tropical forest

2005 ◽  
Vol 21 (4) ◽  
pp. 435-444 ◽  
Author(s):  
Brent C. Blair
Keyword(s):  
Leaf Litter ◽  
Tropical Forests ◽  
Forest Fires ◽  
Soil Heterogeneity ◽  
Fire Effects ◽  
Fire Intensity ◽  
Vegetative Cover ◽  
Soil Resources ◽  
In Fire ◽  
The Impact

Anthropogenic wildfires are becoming increasingly frequent in wet tropical forests. This trend follows that of other anthropogenic disturbances, which are now acute and widespread. Fires pose a potentially serious threat to tropical forests. However, little is known about the impact of unintended forest fires on below-ground resources in these ecosystems. This study investigated the influence of fires on the distribution and variability of soil resources on two sets of 50×50-m burned and unburned plots in a Nicaraguan rain forest. Samples were collected at 5-m intervals throughout each plot as well as subsamples at 50-cm intervals. Geostatistical techniques as well as univariate statistics were used to quantify the spatial autocorrelation and variability of selected nutrients (N, P and K), carbon and standing leaf litter. Most variability in this forest was spatially dependent at a scale of 30 m or less. However the average range of autocorrelations varied greatly between properties and sites. Burning altered soil heterogeneity by decreasing the range over which soil properties were autocorrelated. Overall the average patch size (range) for nitrogen was reduced by 7%, phosphorus by 52%, potassium by 60% and carbon by 43%. While phosphorus and leaf litter increased in the burned plots compared to unburned plots, potassium was not different. Nitrogen and carbon did not display a consistent pattern between burning regimes and this may be explained by variation in fire intensity. Leaf litter measurements did not correlate with measured soil nutrients within plots. Observed changes in the burned forest were likely a result of both the intensity of burning and change in vegetative cover between the time of the fires and soil sampling.

scholarly journals Characterization of Dry-Season Phenology in Tropical Forests by Reconstructing Cloud-Free Landsat Time Series

2021 ◽  
Vol 13 (23) ◽  
pp. 4736
Author(s):  
Xiaolin Zhu ◽  
Eileen H. Helmer ◽  
David Gwenzi ◽  
Melissa Collin ◽  
Sean Fleming ◽  
...  
Keyword(s):  
Time Series ◽  
Puerto Rico ◽  
Tropical Forests ◽  
Tropical Dry Forest ◽  
Dry Season ◽  
Dry Forest ◽  
High Quality ◽  
Forest Zone ◽  
Fine Resolution ◽  
Field Plots

Fine-resolution satellite imagery is needed for characterizing dry-season phenology in tropical forests since many tropical forests are very spatially heterogeneous due to their diverse species and environmental background. However, fine-resolution satellite imagery, such as Landsat, has a 16-day revisit cycle that makes it hard to obtain a high-quality vegetation index time series due to persistent clouds in tropical regions. To solve this challenge, this study explored the feasibility of employing a series of advanced technologies for reconstructing a high-quality Landsat time series from 2005 to 2009 for detecting dry-season phenology in tropical forests; Puerto Rico was selected as a testbed. We combined bidirectional reflectance distribution function (BRDF) correction, cloud and shadow screening, and contaminated pixel interpolation to process the raw Landsat time series and developed a thresholding method to extract 15 phenology metrics. The cloud-masked and gap-filled reconstructed images were tested with simulated clouds. In addition, the derived phenology metrics for grassland and forest in the tropical dry forest zone of Puerto Rico were evaluated with ground observations from PhenoCam data and field plots. Results show that clouds and cloud shadows are more accurately detected than the Landsat cloud quality assessment (QA) band, and that data gaps resulting from those clouds and shadows can be accurately reconstructed (R2 = 0.89). In the tropical dry forest zone, the detected phenology dates (such as greenup, browndown, and dry-season length) generally agree with the PhenoCam observations (R2 = 0.69), and Landsat-based phenology is better than MODIS-based phenology for modeling aboveground biomass and leaf area index collected in field plots (plot size is roughly equivalent to a 3 × 3 Landsat pixels). This study suggests that the Landsat time series can be used to characterize the dry-season phenology of tropical forests after careful processing, which will help to improve our understanding of vegetation–climate interactions at fine scales in tropical forests.

scholarly journals Tropical Dry Forest resilience and Water Use Efficiency: an analysis of productivity under climate change

2021 ◽  
Author(s):  
Kayla D. Stan ◽  
Arturo Sanchez-Azofeifa ◽  
Sandra M. Duran ◽  
Jose Antonio Guzmán Quesada ◽  
Michael Hesketh ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Use Efficiency ◽  
Water Use ◽  
Tropical Dry Forest ◽  
Dry Forest ◽  
Forest Resilience ◽  
Use Efficiency

A 55-year-old natural experiment gives evidence of the effects of changes in fire frequency on ecosystem properties in a seasonal subtropical dry forest

2018 ◽  
Vol 30 (3) ◽  
pp. 266-277 ◽  
Author(s):  
Esteban Kowaljow ◽  
Mariano S. Morales ◽  
Juan I. Whitworth-Hulse ◽  
Sebastián R. Zeballos ◽  
Melisa A. Giorgis ◽  
...  
Keyword(s):  
Natural Experiment ◽  
Fire Frequency ◽  
Dry Forest ◽  
Ecosystem Properties ◽  
In Fire

scholarly journals WHICH VARIABLES IN FOREST SURVEY DATA CAN BETTER DISTINGUISH CONSERVED AND DEGRADED TROPICAL DRY FOREST?

2020 ◽  
Vol XLII-3/W12-2020 ◽  
pp. 309-313
Author(s):  
Y. Gao ◽  
D. Jiménez ◽  
M. Skutsch ◽  
M. Salinas ◽  
J. Solórzano
Keyword(s):  
Statistical Study ◽  
Tropical Dry Forest ◽  
Canopy Cover ◽  
Basal Area ◽  
Remote Sensing Data ◽  
Tree Height ◽  
Forest Degradation ◽  
Dry Forest ◽  
Inventory Data ◽  
Forest Survey

Abstract. This paper presents the results of a statistical study of forest inventory data for tropical dry forest in Ayuquila River Basin, Jalisco state, Mexico. The field inventory was carried out between May-June of 2019 which is at the end of dry season and the beginning of raining season. The field inventory data were collected in 43 plots of 500 m2 each which were designed in a way to include tropical dry forests in two conditions: degraded and conserved. In each plot, the collected data include DBH, tree height, number of trees per plot, and the density of tree stems. A study was carried out to find out if there are statistically significant differences variables relating to forest structure between degraded and conserved status. The Mann-Whitney test shows that there is significant differences in canopy cover, biomass, tree height, and basal area. This information is important since it helps to understand whether and how forest degradation can be detected using remote sensing data.

Importance of the lilac-crowned parrot in pre-dispersal seed predation of Astronium graveolens in a Mexican tropical dry forest

2010 ◽  
Vol 26 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Emma Ines Villaseñor-Sánchez ◽  
Rodolfo Dirzo ◽  
Katherine Renton
Keyword(s):  
Tropical Forests ◽  
Seed Predation ◽  
Tropical Dry Forest ◽  
Ground Level ◽  
Dry Forest ◽  
Seed Predator ◽  
Seed Predators ◽  
Canopy Trees ◽  
Resource Patches ◽  
Fruit Crop Size

Abstract:Parrots represent a large biomass of canopy granivores in tropical forests, and may be effective pre-dispersal seed predators. We evaluated the importance of the lilac-crowned parrot (Amazona finschi) as a pre-dispersal seed predator of Astronium graveolens (Anacardiaceae) in tropical dry forest. Seeds were collected in fruit-traps beneath 22 trees to compare pre-dispersal seed predation by parrots and insects, and determine whether intensity of seed predation was related to fruit-crop size or the aggregation of fruiting conspecifics around focal trees. Ground-level exclosures were established to compare post-dispersal seed predation by vertebrates and insects. The lilac-crowned parrot predated 43% of seeds pre-dispersal, while insects predated only 1.3%. Intensity of pre-dispersal seed predation by parrots was significantly greater in high-fruiting 0.79-ha resource patches, and was not related to fruit abundance of the focal tree. Foraging parrots also discarded immature fruits below the tree, causing a total 56% pre-dispersal loss of seed production, which was greater than post-dispersal removal by vertebrates, mainly rodents (51%) or insects (36%). Our results show that parrots play an important role as pre-dispersal seed predators in tropical dry forests. The reduction of parrot populations in tropical forests may have consequences for seed predation, affecting recruitment patterns of canopy trees.

Post-Fire Regeneration of Woody Species in a Colombian Tropical Dry Forest

2020 ◽  
pp. 324-345
Author(s):  
Anghy Gutiérrez-Rincón ◽  
Angela Parrado-Rosselli
Keyword(s):  
Plant Species ◽  
Forest Fires ◽  
Natural Regeneration ◽  
Tropical Dry Forest ◽  
Woody Species ◽  
Dry Forest ◽  
Forest Sites ◽  
Regeneration Response ◽  
Magdalena River ◽  
In Fire

In fire-influenced ecosystems, some plant species have the ability to recover, germinate, and to establish after a fire; however, their proportion and dominance varies between sites. The objective of this work was to evaluate natural regeneration following a fire in a tropical dry forest located in the Upper Magdalena River Valley in Colombia. In that way, all seedlings and saplings of woody species were recorded, 1.5 years after a fire, in 75 2x2-m plots installed in burned and unburned forest sites, as well as in forest gaps. Results showed that although abundance was higher in the burned sites, the species richness was lower than in unburned areas. Based on the regeneration response of the species, we identified three groups of plants: 1) fire-stimulated, 2) fire-tolerant, and 3) fire-sensitive species, which means that this tropical dry forest has species with the ability to recover, germinate, and establish after a fire. These three groups of plant species should be considered in restoration programs in light of future and more frequent forest fires due to climate change.

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