Does leaf flushing in the dry season affect leaf traits and herbivory in a tropical dry forest?

An understanding of variations in morphophysiological leaf traits of plant models in dry tropical forests is essential for quantifying C fluxes from forest ecosystems in response to climate changes. The present study evaluated the influences of seasonal rainfall and different light conditions on the gas exchange, nutrients, organic compounds and morphological traits in Croton blanchetianus Baill. trees within a fragment of Caatinga forest. Stomatal conductance (gs) and net photosynthesis (PN) demonstrated variations within the diurnal cycle, with maximum values at approximately midday and minimum values at predawn. The PN and the diurnal integrated CO2 assimilation were lower during the dry season than in the rainy season. Water use efficiency was positively correlated with PN (r = 0.73) during the dry season only. However, the correlation between PN and gs was observed during the rainy season only (r = 0.60). Thus we demonstrated that C. blanchetianus has a remarkable ability to adapt to global climatic changes and could be considered a model in studies exploring water relationships in woody plants; consequently, this species may be important in future reforestation studies.

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

Remote Sensing ◽

10.3390/rs13234736 ◽

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.

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Effect of fragmentation on the Costa Rican dry forest avifauna

PeerJ ◽

10.7717/peerj.2422 ◽

2016 ◽

Vol 4 ◽

pp. e2422 ◽

Cited By ~ 5

Author(s):

Gilbert Barrantes ◽

Diego Ocampo ◽

José D. Ramírez-Fernández ◽

Eric J. Fuchs

Keyword(s):

Tropical Dry Forest ◽

Bird Community ◽

Dry Season ◽

Costa Rican ◽

Dry Forest ◽

Forest Fragment ◽

Avian Community ◽

Forest Patches ◽

Species Occupancy ◽

Avian Assemblages

Deforestation and changes in land use have reduced the tropical dry forest to isolated forest patches in northwestern Costa Rica. We examined the effect of patch area and length of the dry season on nestedness of the entire avian community, forest fragment assemblages, and species occupancy across fragments for the entire native avifauna, and for a subset of forest dependent species. Species richness was independent of both fragment area and distance between fragments. Similarity in bird community composition between patches was related to habitat structure; fragments with similar forest structure have more similar avian assemblages. Size of forest patches influenced nestedness of the bird community and species occupancy, but not nestedness of assemblages across patches in northwestern Costa Rican avifauna. Forest dependent species (species that require large tracts of mature forest) and assemblages of these species were nested within patches ordered by a gradient of seasonality, and only occupancy of species was nested by area of patches. Thus, forest patches with a shorter dry season include more forest dependent species.

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Rainfall drives leaf traits and leaf nutrient resorption in a tropical dry forest in Mexico

Oecologia ◽

10.1007/s00442-010-1704-3 ◽

2010 ◽

Vol 165 (1) ◽

pp. 201-211 ◽

Cited By ~ 40

Author(s):

Lyliana Y. Rentería ◽

Víctor J. Jaramillo

Keyword(s):

Tropical Dry Forest ◽

Leaf Traits ◽

Dry Forest ◽

Nutrient Resorption

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Leaf traits and herbivory on deciduous and evergreen trees in a tropical dry forest

Basic and Applied Ecology ◽

10.1016/j.baae.2015.02.005 ◽

2015 ◽

Vol 16 (3) ◽

pp. 210-219 ◽

Cited By ~ 19

Author(s):

Jhonathan O. Silva ◽

Mário M. Espírito-Santo ◽

Helena C. Morais

Keyword(s):

Tropical Dry Forest ◽

Leaf Traits ◽

Dry Forest

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Vertical distribution, nutrient concentration and seasonal changes of fine root mass in a semi-deciduous tropical dry forest and in two adjacent pastures in the Western Llanos of Venezuela

Tropical Grasslands - Forrajes Tropicales ◽

10.17138/tgft(8)93-104 ◽

2020 ◽

Vol 8 (2) ◽

pp. 93-104

Author(s):

Ana Francisca González-Pedraza ◽

Nelda Dezzeo

Keyword(s):

Vertical Distribution ◽

Seasonal Changes ◽

Rainy Season ◽

Nutrient Concentration ◽

Fine Root ◽

Tropical Dry Forest ◽

Dry Season ◽

Dry Forest ◽

Nutrient Concentrations ◽

Root Mass

With the objective to contribute to a better understanding of ecological consequences of deforestation on the below-ground system in the Western Llanos of Venezuela, we evaluated the vertical distribution, nutrient concentration and seasonal changes of total fine root mass (FRM) (<2 mm diameter) in a semi-deciduous tropical dry forest and in 2 adjacent pastures of Cynodon nlemfuensis: a young pasture (YP, 5 years old) and an old pasture (OP, 18 years old) in the Obispo municipality, Barinas State. This evaluation included measurements at the end of the rainy season, during the dry season and during the subsequent early rainy season in 2005/2006. Highest FRM was recorded during the dry season, which probably indicates a plant water-stress response mechanism. The highest proportion (63‒88%) of FRM was concentrated in the 10–20 cm soil layer at all studied sites, probably due to a higher nutrient and moisture content at that depth. Non-significant differences (P>0.05) were observed in the total concentrations of organic carbon, nitrogen, phosphorus, calcium and magnesium in the FRM in soils supporting forest, OP and YP at the evaluated depths. Non-significant changes in the total FRM and nutrient concentrations were observed between the sampling periods and the 3 study sites. YP soils showed a slight increase in FRM that could be associated with the root growth of secondary vegetation, which is considered a weed and is periodically removed. Our results suggest that the land use change from tropical forest to pastures has not significantly affected the mass of fine roots and their carbon and nutrient concentrations. Further studies are needed to determine if these findings apply to other ecosystems.

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Seasonal fruiting and seed dispersal by the brown lemur in a tropical dry forest, north-western Madagascar

Journal of Tropical Ecology ◽

10.1017/s0266467413000011 ◽

2013 ◽

Vol 29 (1) ◽

pp. 61-69 ◽

Cited By ~ 8

Author(s):

Hiroki Sato

Keyword(s):

Seed Dispersal ◽

Feeding Activity ◽

Tropical Dry Forest ◽

Dry Season ◽

Dry Forest ◽

Eulemur Fulvus ◽

Faecal Analysis ◽

North Western ◽

Essential Food

Abstract:Community-wide seasonal fruiting and seed dispersal by the common brown lemur (Eulemur fulvus fulvus) was investigated in a tropical dry forest, north-western Madagascar. The brown lemur is the sole disperser of large seeds > 10 mm in diameter. Considering the limited assemblage of dispersers, large-seeded plants should display distinctive fruiting patterns to acquire dispersers. To compare fruiting patterns and seed dispersal by the brown lemur between small-seeded and large-seeded plants, fruiting conditions for 432 trees on a transect, feeding activity over 1212 h of observation, and the composition of 1126 dung samples were recorded for 1 y. Seeds of a total of 52 species were identified through both observations and faecal analysis. As rainfall increased, larger numbers of species and individuals of small-seeded plants fruited. Among the 52 species, the brown lemur dispersed 29 and 13 species with small and large seeds, respectively, during the rainy season. High moisture levels probably favoured seed germination and seedling establishment in various species. During the dry season, although small-seeded species rarely fruited, a few large-seeded species, particularly Vitex beraviensis, formed a long-term fruiting peak and provided essential food resources for the brown lemur. Because seeds of these large-seeded plants were frequently dispersed by the brown lemur, dry-season fruiting seemed to be favourable to avoid competition for dispersers with other plant species.

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Insect herbivores associated with an evergreen tree Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) in a tropical dry forest

Brazilian Journal of Biology ◽

10.1590/bjb.2014.0093 ◽

2014 ◽

Vol 74 (3) ◽

pp. 623-631 ◽

Cited By ~ 3

Author(s):

JO Silva ◽

FS Neves

Keyword(s):

Tree Species ◽

Rainy Season ◽

Tropical Dry Forest ◽

Dry Season ◽

Dry Forest ◽

Conservation Strategies ◽

Insect Herbivores ◽

Evergreen Species ◽

Evergreen Tree ◽

Leaf Herbivory

Goniorrhachis marginata Taub. (Leguminosae: Caesalpinioideae) is a tree species found in Brazilian tropical dry forests that retain their leaves during the dry season. That being, we addressed the following question: i) How do insect diversity (sap-sucking and chewing), leaf herbivory and defensive traits (tannin and leaf sclerophylly) vary on the evergreen tree species G. marginata between seasons? The abundance of sap-sucking insects was higher in the dry season than in the rainy season. However, we did not verify any difference in the species richness and abundance of chewing insects between seasons. Leaf herbivory was higher in the rainy season, whereas leaf sclerophylly was higher in the dry season. However, herbivory was not related to sclerophylly. Insect herbivores likely decrease their folivory activity during the dry season due to life history patterns or changes in behaviour, possibly entering diapause or inactivity during this period. Therefore, G. marginata acts as a likely keystone species, serving as a moist refuge for the insect fauna during the dry season in tropical dry forest, and the presence of this evergreen species is crucial to conservation strategies of this threatened ecosystem.

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