Monitoring Woody Cover Dynamics in Tropical Dry Forest Ecosystems Using Sentinel-2 Satellite Imagery

Dry forests in Sub-Saharan Africa are of critical importance for the livelihood of the local population given their strong dependence on forest products. Yet these forests are threatened due to rapid population growth and predicted changes in rainfall patterns. As such, large-scale woody cover monitoring of tropical dry forests is urgently required. Although promising, remote sensing-based estimation of woody cover in tropical dry forest ecosystems is challenging due to the heterogeneous woody and herbaceous vegetation structure and the large intra-annual variability in the vegetation due to the seasonal rainfall. To test the capability of Sentinel-2 satellite imagery for producing accurate woody cover estimations, two contrasting study sites in Ethiopia and Tanzania were used. The estimation accuracy of a linear regression model using the Normalised Difference Vegetation Index (NDVI), a Partial Least Squares Regression (PLSR), and a Random Forest regression model using both single-date and multi-temporal Sentinel-2 images were compared. Additionally, the robustness and site transferability of these methods were tested. Overall, the multi-temporal PLSR model achieved the most accurate and transferable estimations (R2 = 0.70, RMSE = 4.12%). This model was then used to monitor the potential increase in woody coverage within several reforestation projects in the Degua Tembien district. In six of these projects, a significant increase in woody cover could be measured since the start of the project, which could be linked to their initial vegetation, location and shape. It can be concluded that a PLSR model combined with Sentinel-2 satellite imagery is capable of monitoring woody cover in these tropical dry forest regions, which can be used in support of reforestation efforts.

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Squamata reptiles of a fragment of tropical dry forest in northwestern Venezuela (Lake Maracaibo region)

Check List ◽

10.15560/8.6.1220 ◽

2012 ◽

Vol 8 (6) ◽

pp. 1220 ◽

Cited By ~ 1

Author(s):

Junior T. Larreal ◽

Gilson A. Rivas ◽

Carlos Portillo-Quintero ◽

Tito R. Barros

Keyword(s):

Species Composition ◽

San Francisco ◽

Tropical Dry Forest ◽

Single Species ◽

Dry Forest ◽

Forest Fragment ◽

Dry Forests ◽

Maracaibo Basin ◽

Lake Maracaibo

We present a commented taxonomic list of the reptiles found during herpetological surveys carried out in an isolated fragment of tropical dry forest located in the municipality of San Francisco, Zulia state, northwestern Venezuela between January-December 2011. We report a total of 24 species belonging to the order Squamata, distributed in 12 families and 21 genera. Colubridae is the most diverse family with six species, followed by Dipsadidae (four species), Boidae, Gymnophthalmidae, Phyllodactylidae and Teiidae with two species each, and finally Dactyloidae, Iguanidae, Elapidae, Gekkonidae, Sphaerodactylidae and Viperidae with a single species each. The species composition at this site matches what would be expected in a tropical dry forest in the region. Our study suggests that this isolated tropical dry forest fragment is the last refuge of the herpetofauna that once occupied much of the dry forests of the northern Maracaibo basin and should therefore be considered for conservation purposes.

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Multiple Factors Influence Seasonal and Interannual Litterfall Production in a Tropical Dry Forest in Mexico

Forests ◽

10.3390/f11121241 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1241

Author(s):

Hernán Morffi-Mestre ◽

Gregorio Ángeles-Pérez ◽

Jennifer S. Powers ◽

José Luis Andrade ◽

Astrid Helena Huechacona Ruiz ◽

...

Keyword(s):

Linear Models ◽

Tropical Dry Forest ◽

Basal Area ◽

Dry Forest ◽

Maximum Temperature ◽

Dry Forests ◽

Evergreen Species ◽

Flat Terrain ◽

Litterfall Production ◽

Successional Age

Litterfall production plays a fundamental role in the dynamics and function of tropical forest ecosystems, as it supplies 70–80% of nutrients entering the soil. This process varies annually and seasonally, depending on multiple environmental factors. However, few studies spanning several years have addressed the combined effect of climate variables, successional age, topography, and vegetation structure in tropical dry forests. In this study, we evaluated monthly, seasonal, and annual litterfall production over a five-year period in semideciduous dry forests of different successional ages growing on contrasting topographic conditions (sloping or flat terrain) in Yucatan, Mexico. Its relationship with climate and vegetation structural variables were also analyzed using multiple linear regression and generalized linear models. Litterfall was measured monthly in 12 litterfall traps of 0.5 m2 in three sampling clusters (sets of four 400 m2 sampling plots) established in forests of five successional age classes, 3–5, 10–17, 18–25, 60–79, and >80 years (in the latter two classes either on slopping or on flat terrain), for a total of 15 sampling clusters and 180 litterfall traps. Litterfall production varied between years (negatively correlated with precipitation), seasons (positively correlated with wind speed and maximum temperature), and months (negatively correlated with relative humidity) and was higher in flat than in sloping sites. Litterfall production also increased with successional age until 18–25 years after abandonment, when it attained values similar to those of mature forests. It was positively correlated with the aboveground biomass of deciduous species but negatively correlated with the basal area of evergreen species. Our results show a rapid recovery of litterfall production with successional age of these forests, which may increase with climate changes such as less precipitation, higher temperatures, and higher incidence of hurricanes.

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Distribution of the community of frugivorous birds along a successional gradient in a tropical dry forest in south-western Mexico

Journal of Tropical Ecology ◽

10.1017/s0266467414000601 ◽

2014 ◽

Vol 31 (1) ◽

pp. 57-68 ◽

Cited By ~ 10

Author(s):

R. Carlos Almazán-Núñez ◽

María del Coro Arizmendi ◽

Luis E. Eguiarte ◽

Pablo Corcuera

Keyword(s):

Tropical Dry Forest ◽

Dry Season ◽

Dry Forest ◽

Forest Fragments ◽

Dry Forests ◽

Bird Abundance ◽

Frugivorous Birds ◽

Seed Predators ◽

Western Mexico ◽

Successional Forests

Abstract:Few reports have described the relationship between the distribution of frugivorous birds and vegetation successional changes in dry forests. We assessed the abundance and behaviour of frugivorous birds in early, intermediate and mature dry forests in the Balsas river basin, Guerrero, Mexico. We selected nine dry-forest fragments, three fragments per stage, in these three stages of succession. We analysed the vegetation, estimated bird abundances in 10-min count periods, and recorded the way birds process fruits in circular plots (11–15 plots per fragment, 123 plots in total). Birds were classified as seed predators (15% of all individuals in this study), pulp consumers (15%) or legitimate dispersers (70%). Bird abundance was higher in mature forests in the dry season, while abundance and richness of legitimate dispersers and seed predators were positively related to vegetation complexity. Mature forests have a high vegetation complexity and a high cover ofBurseraspecies that produce fruit during the dry season. During the rains, abundance was higher in early-successional sites when the zoochorous plants produced fruit. Legitimate disperser migrants (i.e.Tyrannus vociferans, Myiarchus cinerascensandM. tyrannulus) were widespread, helping the establishment of zoochorous trees such asBurseraspp. in early-successional forests.

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GERMINATION OF STORED SEEDS OF FOUR TREE SPECIES FROM THE TROPICAL DRY FOREST OF MORELOS, MEXICO

Botanical Sciences ◽

10.17129/botsci.96 ◽

2014 ◽

Vol 92 (2) ◽

pp. 281 ◽

Cited By ~ 3

Author(s):

Martha Cervantes ◽

Eliane Ceccon ◽

Consuelo Bonfil

Keyword(s):

Seed Germination ◽

Seed Size ◽

Storage Time ◽

Germination Rate ◽

Tropical Dry Forest ◽

Dry Forest ◽

Tropical Dry Forests ◽

Germination Capacity ◽

Dry Forests ◽

And Storage

Studies on propagation of trees of Tropical Dry Forests are scarce in Mexico, besides, the provenance of seeds used in reforestation programs is generally unknown or poorly addressed. Knowledge on seed germination patterns of different provenances, and how they change through time, is useful to identify adequate sources of seeds and to develop seed collection and storage programs under the low-tech conditions prevailing in most rural nurseries. We evaluated seed size variation and germination of stored seeds from three different provenances per species in Acacia bilimekii, Haematoxylum brasiletto, Lysiloma acapulcense, and L. divaricatum. Seeds were collected in four sites in the Tropical Dry Forest of Morelos, Mexico, and were stored at room temperature; seed size was estimated through the volume of 75 seeds per provenance/species. Seed germination tests were made periodically from six to 24 months after storage and the effects of provenance and storage time on germination were analyzed using Anovas. There were significant differences in seed size among provenances in all species, while the effect of provenance on germination rate was significant in three of them. Germination rate changed with storage time among species and provenances. After 24 months, germination capacity was still ≥ 50% in all provenances of the two Lysiloma species, but in A. bilimekii there were large differences among provenances. Mean germination capacity was low in H. brasiletto after six months. More research on seed germination and storage of a larger set of species and provenances is needed to restore the Mexican tropical dry forests.

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Spatial Estimation of the Latent Heat Flux in a Tropical Dry Forest by Using Unmanned Aerial Vehicles

Forests ◽

10.3390/f11060604 ◽

2020 ◽

Vol 11 (6) ◽

pp. 604 ◽

Cited By ~ 1

Author(s):

Philip Marzahn ◽

Linda Flade ◽

Arturo Sanchez-Azofeifa

Keyword(s):

Heat Flux ◽

Latent Heat ◽

Latent Heat Flux ◽

Tropical Dry Forest ◽

Dry Forest ◽

Tropical Dry Forests ◽

Dry Forests ◽

Flux Tower ◽

Spatially Distributed ◽

Triangle Method

In this paper, we address the retrieval of spatially distributed latent heat flux ( λ E) over a tropical dry forest using multi-spectral and thermal unmanned aerial vehicle (UAV) imagery. The study was carried out in the Santa Rosa National Park Environmental Monitoring Super-Site, Costa Rica, in June 2016. The triangle method was used to derive λ E from the UAV imagery and the results were compared to λ E measurements of an eddy covariance system within the coincident eddy flux tower footprint. The tower footprint was derived using a two-dimensional parameterization model for flux footprint prediction. The comparisons with the flux tower measurements showed a mean relative difference of 10.98% with a slight overestimation of the UAV-based flux retrievals by nearly 7.7 Wm − 2 . The results are in good agreement with satellite-based retrievals, as provided by the literature, for which the triangle method was initially developed and mostly used so far. This study proved to be a promising approach for transferring the triangle method to UAV imagery in ecosystems such as tropical dry forests. With the presented approach, new details in spatially distributed latent heat flux estimates at ultra-high resolution are now possible, thereby potentially closing the gap in spatial resolution between satellites and flux towers. Even more, it allows tracing the latent heat flux from single trees at leaf level. Besides, this approach also opens new perspectives for the monitoring of latent heat fluxes in tropical dry forests.

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Lepidoptera are Relevant Bioindicators of Passive Regeneration in Tropical Dry Forests

Diversity ◽

10.3390/d12060231 ◽

2020 ◽

Vol 12 (6) ◽

pp. 231 ◽

Cited By ~ 2

Author(s):

Luc Legal ◽

Marine Valet ◽

Oscar Dorado ◽

Jose Maria de Jesus-Almonte ◽

Karime López ◽

...

Keyword(s):

Anthropogenic Disturbance ◽

Tropical Dry Forest ◽

Dry Forest ◽

Tropical Dry Forests ◽

Primary Forest ◽

Dry Forests ◽

Study Zone ◽

Butterfly Communities ◽

Passive Regeneration ◽

Different Levels

Most evaluations of passive regeneration/natural succession or restoration have dealt with tropical rain forest or temperate ecosystems. Very few studies have examined the regeneration of tropical dry forests (TDF), one of the most damaged ecosystem types in the world. Owing to their species diversity and abundance, insects have been widely used as bioindicators of restoration. Butterflies were among the most abundant and useful groups. We sampled four sites with different levels of anthropogenic disturbance in a Mexican TDF (Morelos State) and compared butterfly communities. A first goal was to examine whether adult butterflies were significant bioindicators owing to their specificity to restricted habitats. A second aim was to determine if differences exist in butterfly communities between some fields abandoned from 4–8, 8–15 and 15–30 years and a reference zone considered as primary forest. We found 40% to 50% of the species of butterflies were specifically related to a habitat and/or a level of anthropogenic disturbance. The time it takes for passive regeneration and recovery of the Mexican tropical dry forest is much higher than 25 years (our older zone), considering that almost none of the butterflies found in our conserved reference zone were present in our 25 year aged study zone.

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Tree community change in a tropical dry forest: the role of roads and exotic plant invasion

Environmental Conservation ◽

10.1017/s0376892909990257 ◽

2009 ◽

Vol 36 (3) ◽

pp. 201-207 ◽

Cited By ~ 14

Author(s):

AYESHA E. PRASAD

Keyword(s):

Tropical Dry Forest ◽

Community Change ◽

Dry Forest ◽

Tropical Dry Forests ◽

Exotic Plant ◽

Dry Forests ◽

Exotic Plant Invasion ◽

Tree Community ◽

Tree Communities ◽

Road Width

SUMMARYAmong the most endangered tropical ecosystems, tropical dry forests are threatened by degradation that includes edge effects arising from perturbations such as the creation and maintenance of roads and other clearings. While much is known about these adverse effects on tree communities in tropical moist forests, similar effects in tropical dry forests are little understood. This paper examines the relationship between roads, road-related exotic plant invasion and tree community change in a tropical dry forest in southern India. Forty pairs of roadside and interior plots across four factorial combinations of road width (wide and narrow) and understorey type (native and exotic) were sampled. Tree death and extant tree community composition were compared using generalized linear models and similarity analyses. Tree death near roads was more than double that away from them, suggesting that roads may increase tree death in these forests. The interactive effect of understorey type (exotic or native) and road width on tree death was significant, with highest tree death near wide roads bordered by exotic understorey. Conversely, tree community composition was influenced by road width and understorey type, but not by proximity to roads. Creation and maintenance of roads for forest management may have serious implications for tree communities in tropical dry forests and should thus be minimized. Exotic plants may also be important contributors to increasing tree death, and further research on their impacts, particularly into underlying mechanisms, is critical to the long-term conservation of tropical dry forest communities.

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Floristic similarity between adult and saplings strata of Caatinga hyperxerophilous woody vegetation – a Brazilian seasonally tropical dry forest

Revista Forestal Mesoamericana Kurú ◽

10.18845/rfmk.v17i41.5225 ◽

2020 ◽

Vol 17 (41) ◽

pp. 2-15

Author(s):

Marcelo Silva De Lucena ◽

Alan Cauê De Holanda ◽

Allyson Rocha Alves

Keyword(s):

Forest Ecosystems ◽

Tropical Dry Forest ◽

Local Scale ◽

Dry Forest ◽

Floristic Similarity ◽

Species Groups ◽

Local Differentiation ◽

Mechanisms Of Persistence ◽

And Control ◽

Sørensen Index

In the Caatinga, the maintenance of forest ecosystems depends on natural regeneration and several factors that can act in two ways: 1) provide the perpetuation of communities composheed of few species that dominate the adult and saplings strata, resulting in floristic similarities; 2) provide local differentiation between adult and saplings strata. However, these relationships remain poorly understood, as it is not known whether the factors acting on a local scale favor the floristic similarity between the adult and saplings strata or if these patterns are found in conserved and anthropized areas. This work evaluated the floristic similarity between the adult and saplings strata of hyperxerophilous caatinga woody-shrubby vegetation in conserved and anthropized areas. In two areasof conserved and anthropized hyperxerophilous Caatinga, adult and saplings individuals were measured and floristic richness and qualitative floristic similarity were evaluated. The floristic similarity between the adult and saplings strata was statistically compared using the Chao-Sørensen index. In both sites, although there was a large number of species exclusive to the adult stratum, the Chao-Sørensen index indicates high floristic similarity between strata. The analysis of this behavior together with the assessment of community structure shows that few species can be responsible for the key processes that structure and control the main mechanisms of persistence of these ecosystems. This can be attributed to the existence of locally uniform conditions that can define the dominance of adapted species groups.

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Aspergillus and Penicillium (Eurotiales: Trichocomaceae) in soils of the Brazilian tropical dry forest: diversity in an area of environmental preservation

Revista de Biología Tropical ◽

10.15517/rbt.v64i1.18223 ◽

2016 ◽

Vol 64 (1) ◽

pp. 45 ◽

Cited By ~ 3

Author(s):

Renan Do Nascimento Barbosa ◽

Jadson Diogo Pereira Bezerra ◽

Phelipe Manoel Oller Costa ◽

Nelson Correia de Lima-Júnior ◽

Ivana Roberta Gomes Alves de Souza Galvão ◽

...

Keyword(s):

Tropical Dry Forest ◽

Culture Collection ◽

Soil Samples ◽

Dry Forest ◽

Dry Forests ◽

Complex Biological System ◽

Environmental Preservation ◽

Forest Diversity ◽

Sabouraud Agar ◽

Evenness Indices

Soil is a complex biological system that plays a key role for plants and animals, especially in dry forests such as the Caatinga. Fungi from soils, such as Aspergillus and Penicillium, can be used as bioindicators for biodiversity conservation. The aim of this study was to isolate and identify species of Aspergillus and Penicillium in soil, from the municipalities of Tupanatinga and Ibimirim, with dry forests, in the Catimbau National Park. Five collections were performed in each area during the drought season of 2012, totaling 25 soil samples per area. Fungi were isolated by suspending soil samples in sterile distilled water and plating on Sabouraud Agar media plus Chloramphenicol and Rose Bengal, and Glycerol Dicloran Agar. Isolates were identified by morphological taxonomy in the Culture Collection Laboratory and confirmed by sequencing of the Internal Transcribed Spacer of rDNA. A total of 42 species were identified, of which 22 belong to the genus Aspergillus and 20 to Penicillium. Penicillium isolates showed uniform distribution from the collecting area in Tupanatinga, and the evenness indices found were 0.92 and 0.88 in Tupanatinga and Ibimirim, respectively. Among isolates of Aspergillus evenness, the value found in Tupanatinga (0.85) was very close to that found in Ibimirim (0.86). High diversity and low dominance of fungi in soil samples was observed. These results contributed to the estimation of fungal diversity in dry environments of the Caatinga, where diversity is decreasing in soils that have undergone disturbance.

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An Overview of the Role of Plant Functional Traits in Tropical Dry Forests

Practice, Progress, and Proficiency in Sustainability - Handbook of Research on the Conservation and Restoration of Tropical Dry Forests ◽

10.4018/978-1-7998-0014-9.ch005 ◽

2020 ◽

pp. 89-113

Author(s):

Abhinav Yadav ◽

Pramit Verma ◽

Akhilesh Singh Raghubanshi

Keyword(s):

Forest Restoration ◽

Rainfall Variability ◽

Tropical Dry Forest ◽

Functional Trait ◽

Research Field ◽

Dry Forest ◽

Tropical Dry Forests ◽

Dry Forests ◽

Interannual Rainfall Variability ◽

Restoration Practice

Tropical dry forests (TDFs) are characterized by pronounced seasonality in precipitation, with several months of prolonged drought, 80% of annual precipitation occurring during a four- to six-month rainy season, and high interannual rainfall variability. Surprisingly, there are relatively few studies addressing patterns of functional trait in tropical dry forest (TDF) ecosystems. Functional trait analysis across plant species and the environment is a rapidly developing research field with many possible applications for forest restoration practice. Trait-based ecological research within TDFs will advance our understanding of how these ecosystems interact with and differ from other tropical ecosystems.

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