scholarly journals Comment on “The extent of forest in dryland biomes”

Science ◽  
2017 ◽  
Vol 358 (6364) ◽  
pp. eaao0369 ◽  
Author(s):  
Marcelino de la Cruz ◽  
Pedro F. Quintana-Ascencio ◽  
Luis Cayuela ◽  
Carlos I. Espinosa ◽  
Adrián Escudero
Keyword(s):  
Sampling Design ◽  
Dry Forest ◽  
Dry Forests ◽  
Critical Areas ◽  
Forest Distribution ◽  
Definition Of

The study by Bastin et al. (Reports, 12 May 2017, p. 635) is based on an incomplete delimitation of dry forest distribution and on an old and incorrect definition of drylands. Its sampling design includes many plots located in humid ecosystems and ignores critical areas for the conservation of dry forests. Therefore, its results and conclusions may be unreliable.

scholarly journals More than Drylands but Less of Dry Forests

2017 ◽  
Author(s):  
Marcelino de la Cruz ◽  
Pedro F. Quintana-Ascencio ◽  
Luis Cayuela ◽  
Carlos I. Espinosa ◽  
Adrián Escudero
Keyword(s):  
Sampling Design ◽  
Dry Forests ◽  
Critical Areas

AbstractThe recent Global Drylands Assessment of forests is based on both an incomplete delimitation of dry forests distribution and on an old and incorrect delimitation of drylands. Its sampling design includes a large proportion of plots located in humid ecosystems and ignores critical areas for the conservation of dry forests. Therefore its results and conclusions are unreliable.

Utilisation of wild growing yams as supplementary nutrition and its impact on the dry forest ecosystem in north-western Madagascar

2004 ◽  
Vol 155 (3-4) ◽  
pp. 80-88 ◽  
Author(s):  
Klaus Ackermann
Keyword(s):  
Forest Ecosystem ◽  
Rainy Season ◽  
Secondary Forest ◽  
Local Population ◽  
Dry Forest ◽  
Dry Forests ◽  
Supplementary Food ◽  
Wild Yams ◽  
Supplementary Nutrition ◽  
North Western

Wild growing yams (Dioscorea spp.) are an important supplementary food in Madagascar, especially during periods of rice shortage in the rainy season. Yams grow in dry forests and there is a particularly high occurrence of yam tubers in recently burned, open secondary forest formations. The study found that the uncontrolled harvest of yams can contribute to the degradation of dry forests due to the high quantity of wild yams harvested by the local population and the widespread practice of intentionally burning forests to increase yams production.

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

Check List ◽  
2012 ◽  
Vol 8 (6) ◽  
pp. 1220 ◽  
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.

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

Forests ◽  
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.

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

2014 ◽  
Vol 31 (1) ◽  
pp. 57-68 ◽  
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.

scholarly journals Using birds to set conservation priorities for Pantanal wetland forests, Brazil

2011 ◽  
Vol 22 (2) ◽  
pp. 155-169 ◽  
Author(s):  
JOÃO BATISTA DE PINHO ◽  
MIGUEL ÂNGELO MARINI
Keyword(s):  
Bird Species ◽  
Dry Forest ◽  
Evergreen Forest ◽  
Conservation Priorities ◽  
Forest Types ◽  
Dry Forests ◽  
Point Counts ◽  
Evergreen Forests ◽  
Local Species Richness ◽  
Bird Richness

SummaryThe Pantanal of Brazil, one of the largest wetlands in the world, is suffering severe threats, such as forest and grassland clearance on the surrounding plateau, conversion of forests and savannas for cattle ranching and effects of large development projects. We used richness, abundance and composition of bird species in four forest types to propose conservation priorities for the northern Pantanal. Birds from 11 sites (a total of 41 points) were sampled through point counts and mist-netting. In total 215 species were recorded in the forests. Two evergreen forest types (cambarazal and landi) had higher estimates of bird richness and abundance than two dry forest types (carvoeiro and cordilheira). The evergreen forests also had more species exclusive to them and were more similar to each other than the dry forests. Selection of forests to be conserved in the northern Pantanal should give priority to evergreen forests and secondarily to dry forests. Cambarazal should be the first forests to be conserved. If the Pantanal inundation cycle is altered by the construction of hydroelectric dams or the Paraguay-Paraná waterway, cambarazal and landi may no longer become flooded, decreasing local species richness. Before our recommendations are considered for conservation and management decisions, more studies on other groups of organisms should also be taken into consideration, and similar studies should be conducted in other regions of the Pantanal. Conservation of Pantanal forest birds depends on a deeper understanding of their use of several habitats, stronger protection of the forests with higher diversity, and public policies that guarantee the long term maintenance of natural flooding cycles.

scholarly journals Evaluating critiques of evidence of historically heterogeneous structure and mixed-severity fires across dry-forest landscapes of the western USA

2021 ◽  
Author(s):  
William L. Baker ◽  
Chad T. Hanson ◽  
Mark A. Williams ◽  
Dominick A. DellaSala
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Large Body ◽  
Dry Forest ◽  
Aerial Photographs ◽  
Heterogeneous Structure ◽  
Dry Forests ◽  
Western Usa ◽  
Published Evidence ◽  
Land Survey

The structure and role of fire in historical dry forests, ponderosa pine (Pinus ponderosa) and dry mixed-conifer forests, of the western USA, have been debated for 25 years, leaving two theories. The first, that these forests were relatively uniform, low in tree density and dominated by low- to moderate-severity fires was recently reviewed, including a critique of opposing evidence. The second, that these forests historically had heterogeneous structure and a mixture of fire severities, has had several published reviews. Here, as authors in part of the second theory, we critically examined evidence in the first theory’s new review, which presented 37 critiques of the second theory. We examined evidence for and against each critique, including evidence presented or omitted. We found that a large body of published evidence against the first theory and supporting the second theory, presented in 10 published rebuttals and 25 other published papers, by us and other scientists, was omitted and not reviewed. We reviewed omitted evidence here. Omitted evidence was extensive, and included direct observations by early scientists, maps in early forest atlases, early newspaper accounts and photographs, early aerial photographs, seven paleo-charcoal reconstructions, ≥18 tree-ring reconstructions, eight land-survey reconstructions, and an analysis of forest-inventory age data. This large body of omitted published research provides compelling evidence supporting the second theory, that historical dry forests were heterogeneous in structure and had a mixture of fire severities, including high-severity fire. The first theory is rejected by this large body of omitted evidence.

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

2014 ◽  
Vol 92 (2) ◽  
pp. 281 ◽  
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

<p><span style="font-size: medium;"><span style="font-family: Times New Roman;">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 <em>Acacia bilimekii</em>, <em>Haematoxylum brasiletto</em>, <em>Lysiloma acapulcense</em>, and<em> L. divaricatum</em>.<em> </em>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 <em>Lysiloma</em> species, but in <em>A.</em> <em>bilimekii</em> there were large differences among provenances. Mean germination capacity was low in <em>H. brasiletto</em> 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. </span></span></p>

scholarly journals Climate change effects on early stages of Quercus ariifolia (Fagaceae), an endemic oak from seasonally dry forests of Mexico

2019 ◽  
Author(s):  
Ernesto I. Badano ◽  
Francisco A. Guerra-Coss ◽  
Erik J. Sánchez-Montes de Oca ◽  
Carlos I. Briones-Herrera ◽  
Sandra M. Gelviz-Gelvez
Keyword(s):  
Climate Change ◽  
Functional Traits ◽  
Rainy Season ◽  
Extinction Risk ◽  
Seedling Emergence ◽  
Dry Forest ◽  
Tree Seedlings ◽  
Dry Forests ◽  
Tree Recruitment ◽  
Seasonally Dry

Background and Aims: Tree recruitment in seasonally dry forests occurs during the rainy season. However, higher temperatures and reduced rainfalls are expected in these ecosystems because of climate change. These changes could induce drought conditions during the rainy season and affect tree recruitment. Plants subjected to thermal or water stress often display morphological and physiological shifts addressed to prioritize their survival. If recently emerged tree seedlings display these responses, this could improve their development during the rainy season and increase their survival chances. Our aim was to test whether recently emerged oak seedlings display these responses.Methods: We performed a field experiment with Quercus ariifolia, an oak species endemic to seasonally dry forests of central Mexico. At the beginning of the rainy season (September 2016), we sowed acorns of this species in control plots under the current climate and plots in which climate change was simulated by increasing temperature and reducing rainfall (CCS plots). Seedling emergence and survival were monitored every seven days during the rainy season (until January 2017). At the end of the experiment, we measured several functional traits on surviving seedlings and compared them between controls and CCS plots.Key results: Higher temperature and lower rainfall generated water shortage conditions in CCS plots. This did not affect emergence of seedlings but reduced their survival. Seedlings that survived in CCS plots displayed shifts in their functional traits, which matched with those of plants subjected to thermal and water stress.Conclusions: Our results suggest that climate change can increase the extinction risk of Q. ariifolia in seasonally dry forest of Mexico by reducing the survival of its offspring. Nevertheless, the results also suggest that seedlings developed under climate change conditions can display functional shifts that could confer them tolerance to increased drought.

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