Dry forests of the Galápagos: a comparative assessment of a World Heritage Site

2020 ◽  
Vol 26 (2) ◽  
pp. 161
Author(s):  
Thomas W. Gillespie ◽  
Gunnar Keppel ◽  
Chelsea M. Robinson ◽  
Gonzalo Rivas-Torres
Keyword(s):  
Species Richness ◽  
Woody Plants ◽  
Native Species ◽  
Forest Cover ◽  
Conservation Status ◽  
Dry Forest ◽  
World Heritage Site ◽  
Dry Forests ◽  
Forest Region ◽  
The Pacific

Despite worldwide knowledge of the importance of the Galápagos archipelago, there is little comparative plot data from the forests in the dry regions. We examined patterns of woody plant (≥2.5cm diameter at breast height (DBH)) species richness and structure using Gentry’s transect method (0.1ha) on the three largest islands in the Galápagos. We identified the conservation status of woody plants within the dry forest region, assessed forest cover and change in the region, and compared field results to other tropical dry forests in the Pacific. Of the 22 species encountered (11 native, 11 endemic), there were no non-native species and only one threatened species. Isabela, Santa Cruz and San Cristóbal have similar overall levels of species, genera, family and liana richness per site, but significantly different tree species richness, density and tree height per transect. Geospatial databases identified 51 species (native 40%, endemic 60%) of woody plants (≥2.5cm DBH) within the dry forest region of the Galápagos and 13 species (10 from the genus Scalesia) on the IUCN Red List. There is an estimated 551.97km2 of dry forest in the Galápagos and there has been little change (<0.01%) in forest cover from 2000 to 2015. Dry forests of the Galápagos have similar levels of species richness to Hawaii and the Marquesas but contain lower densities, basal areas and tree heights than other dry forests in the Pacific. These dry forests appear to be the best preserved and protected tropical dry forest in the Pacific.

scholarly journals Estructura, composición y diversidad de la selva baja caducifolia del Cerro Verde, Nizanda (Oaxaca), México

2017 ◽  
pp. 19 ◽  
Author(s):  
José A. Gallardo-Cruz ◽  
Jorge A. Meave ◽  
Eduardo A. Pérez-García
Keyword(s):  
Species Richness ◽  
Forest Cover ◽  
Conservation Status ◽  
Tropical Dry Forest ◽  
Basal Area ◽  
Floristic Composition ◽  
Dry Forest ◽  
Tropical Region ◽  
Mean Values ◽  
Seasonally Dry

In this study we describe the structure, floristic composition, and diversity of the tropical dry forest established on the Cerro Verde (Verde Hill), located at Nizanda (Isthmus of Tehuantepec, Oaxaca, Mexico). We censused woody plants with DBH Ɛ 1 cm (upper stratum) present in 30 100-m2 plots, and in five 4-m2 subplots within each of them, those plants with height > 30 cm but < 1 cm DBH (lower stratum). A total of 194 species belonging to 52 families were recorded. Species richness was identical in both strata (145 species), each contributing exclusively with ca. 25% of total recorded richness. Leguminosae was the most speciose family (27), followed by Asteraceae (20) and Euphorbiaceae (18). The most frequent species were Bursera simaruba + B. aff. cinerea (not distinguished in the field), Euphorbia schlechtendalii, Pilosocereus collinsii and Capparis verrucosa. Average richness by plot was 30 species. Mean values of indices based on species richness and abundances (Berger-Parker = 0.20;  Simpson = 0.09; Fisher’s[= 9.47; Shannon = 2.78; eveness = 0.82) indicated a high diversity and consequently a low dominance in this forest. Extrapolated values showed a total (upper + lower strata) density of 23,950 ind. ha-1 (830 ind. ha-1 with DBH Ɛ 10 cm), a forest cover of 446.7%, and a basal area of 53 m2 ha-1. Mean height of those individuals accounting for 10% of the highest trees by plot was 9.1 m. Tropical dry forest structure at Cerro Verde is comparable to other Mexican communities within the seasonally dry tropical region and indicates a good conservation status. This feature, together with its particular floristic composition, makes of this area a high priority site which requires inclusion in a formal conservation scheme.

scholarly journals Prioritizing conservation of tropical dry forests in the Pacific

Oryx ◽  
2014 ◽  
Vol 48 (3) ◽  
pp. 337-344 ◽  
Author(s):  
Thomas W. Gillespie ◽  
Kristin O'Neill ◽  
Gunnar Keppel ◽  
Stephanie Pau ◽  
Jean-Yves Meyer ◽  
...  
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Threatened Species ◽  
New Caledonia ◽  
Plant Species Richness ◽  
Dry Forest ◽  
Tropical Dry Forests ◽  
Conservation Priority ◽  
Dry Forests ◽  
The Pacific

AbstractTo identify forests of high priority for conservation in tropical dry forests of New Caledonia, Fiji, the Marquesas and Hawaii, we examined patterns of woody plant species richness (total, native and endemic) and threatened species (IUCN categorization and density) at the stand level, using Gentry's transect method. There were associations between total, native and endemic plant species richness in all four Pacific dry forest regions but we found no significant association with the presence or density of species listed on the IUCN Red List. Dry forests in New Caledonia and Hawaii merit the highest conservation priority in the Pacific, based on level of endemism and number of threatened species. The study sites that merit high conservation priority are Metzdorf, Nekoro and Pindai, in New Caledonia, Kokee and Kaupulehu, in Hawaii, and Vatia, in Fiji. New Caledonia and Fiji have a small dry forest extent and protected area extent compared with other dry forests in biodiversity hotspots. Although we identified priority areas for dry forest conservation, more comparative plot data, presence/absence data in fragments and regional geographical data are needed to adequately manage and protect dry forests in the Pacific.

Regeneration beneath a dioecious tree species (Spondias purpurea) in a Mexican tropical dry forest

2014 ◽  
Vol 30 (3) ◽  
pp. 265-268 ◽  
Author(s):  
Moisés Méndez-Toribio ◽  
Ana María González-Di Pierro ◽  
Mauricio Quesada ◽  
Julieta Benítez-Malvido
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Seedling Recruitment ◽  
Tropical Dry Forest ◽  
Dry Forest ◽  
Total Density ◽  
Dioecious Plant ◽  
Nucleation Sites ◽  
The Pacific ◽  
Spondias Purpurea

Abstract:In dioecious plant species different frugivore activity between genders may influence the abundance and richness of the seedling banks underneath their canopies throughout seed removal and dispersal. In the tropical dry forest of Chamela, on the Pacific Coast of Mexico, the role of S. purpurea female trees as nucleation sites of regeneration was investigated. The standing density, species richness and dispersal syndrome of woody seedlings (i.e. trees and shrubs, 10–100 cm tall) recruited underneath and outside the canopy of 10 male and 10 female S. purpurea trees were recorded in a total of 160 1-m2 plots. Total density was greater in seedling communities associated with female trees (i.e. underneath and outside their canopies) as compared with male trees (231 vs. 153 seedlings, respectively); whereas overall species richness was greater underneath female canopies. Further, the density of zoochorous species were greater underneath the canopy of S. purpurea females (range = 0–5 plants m−2), than elsewhere (outside female canopies, range = 0–3 plants m−2; underneath and outside male canopies, range = 0–2 plants m−2), suggesting a directional dispersal bias towards them. Females of dioecious plant species may act as nucleation sites of initial seedling recruitment in tropical dry forests.

scholarly journals Reptile diversity and community composition in the Puyango dry forest

2016 ◽  
Author(s):  
Acosta Vásconez Ana ◽  
Cisneros-Heredia Diego ◽  
Keyword(s):  
Natural History ◽  
Deciduous Forest ◽  
Conservation Status ◽  
Dry Forest ◽  
Tropical Dry Forests ◽  
Pitfall Traps ◽  
Phylogenetic Groups ◽  
Dry Forests ◽  
History Of ◽  
Dry Deciduous Forest

Reptiles are key animals in vertebrate communities in most ecosystems. However, there is little information on their diversity and abundance in dry forests of Ecuador. Between 2013 and 2014 we studied the reptile diversity and natural history of the Puyango Protected Forest, on the border between the province of Loja and El Oro, Ecuador. This area protects relicts of dry deciduous forest in hills and patches of semi-deciduous forest around ravines. We used belt transects in three different streams and irregular band transects in trails, together with pitfall traps, funnel traps, and litter quadrants. The richness of the Puyango Protected Forest represents a small percentage of the Ecuadorian reptile diversity, but covers much of the representative phylogenetic groups of tropical dry forests of the world. Sampling was effective to determine saurian diversity, but more sampling is needed to estimate snake diversity. Evidence of the presence of 21 species, divided into 10 families, was obtained; of which 14 are snakes (including a potential new species of the genus Epictia) and seven are lizards. Natural history is described for each species, including time and space use, and their conservation status is analyzed. The reptile community is characterized by a relative homogeneity over the vegetation remnants and the highest abundances correspond to saurian species.

scholarly journals BIOLOGICAL DIVERSITY IN COLOMBIAN CARIBBEAN DRY FOREST REMNANTS IN ATLÁNTICO: LICHEN COMMUNITIES IN THE DISTRITO REGIONAL DE MANEJO INTEGRADO LURIZA AND THE RESERVA FORESTAL PROTECTORA EL PALOMAR

Caldasia ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 194-214 ◽  
Author(s):  
Robert Lücking ◽  
Bibiana Moncada ◽  
María Cristina Martínez-Habibe ◽  
Beatriz E. Salgado-Negret ◽  
Marcela Celis ◽  
...  
Keyword(s):  
Species Richness ◽  
Woody Plants ◽  
Biological Diversity ◽  
New Records ◽  
Dry Forest ◽  
Central American ◽  
Seasonally Dry ◽  
Forest Remnants ◽  
High Level ◽  
First Time

We present a first study of the diversity and community composition of lichens in seasonally dry tropical forest (DTF) remnants in the Atlántico department, Colombia. Lichens were sampled in two of the three protected areas of the department: Distrito de Manejo Integrado (DMI) Luriza and Reserva Forestal Protectora (RFP) El Palomar. The inventory revealed 61 species, including four new to science: Fissurina linoana Lücking, Moncada & G. Rodr. sp. nov., Graphis lurizana Lücking, Moncada & Celis sp. nov., G. mokanarum Lücking, Moncada & M.C. Martínez sp. nov., and Phaeographis galeanoae Lücking, Moncada & B. Salgado-N. sp. nov. Arthonia erupta and Coenogonium saepincola are new to South America, whereas thirteen species are recorded for Colombia for the first time. Further 37 species are new records for Atlántico, raising the total of species known from the department from 27 to 84. With 42 species at Luriza and 31 at El Palomar, species richness was comparable to that of other DTF sites in the Neotropics. Overlap in species composition between the two sites was remarkably low, with only twelve shared species (20 %), indicating a high level of heterogeneity. Biogeographical affinities lie with Central American DTF, which is in line with those of woody plants. These results underline the importance of the remaining fragments of DTF in Colombia in conserving partially unknown biodiversity and the necessity for their continuing conservation.

Dry forest is more threatened but less protected than evergreen forest in Ecuador’s coastal region

2020 ◽  
Vol 47 (2) ◽  
pp. 79-83 ◽  
Author(s):  
Carlos A Rivas ◽  
Rafael M Navarro-Cerillo ◽  
Jon C Johnston ◽  
José Guerrero-Casado
Keyword(s):  
Protected Areas ◽  
Endemic Species ◽  
Conservation Status ◽  
Coastal Region ◽  
Dry Forest ◽  
Evergreen Forest ◽  
National Strategy ◽  
Dry Forests ◽  
Evergreen Forests

SummaryThe Ecuadorian coast has two main types of forests, which are differentiated by their phenology: dry forests are deciduous and more humid forests are evergreen. Less of the dry forests on the Ecuadorian coast is protected (13% of its area) than the evergreen forests (28%), and the area devoted to the protection of dry forests (1069 km2) is substantially less than the area devoted to the protection of evergreen forests (2800 km2). Yet the conservation status of dry forests is more critical, with 83% of their area classified as having very low connectivity, 70% as being highly fragile and 86% as being highly threatened. In addition, the dry forests have fewer protected areas than the evergreen forests. It is therefore necessary to increase the protection of deciduous ecosystems as part of a comprehensive national strategy because they support high levels of biodiversity and many endemic species.

scholarly journals Deforestation and fragmentation trends of seasonal dry tropical forest in Ecuador: impact on conservation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Carlos A. Rivas ◽  
José Guerrero-Casado ◽  
Rafael M. Navarro-Cerillo
Keyword(s):  
Protected Areas ◽  
Surface Area ◽  
Patch Size ◽  
Deciduous Forest ◽  
Conservation Status ◽  
Dry Forest ◽  
Edge Density ◽  
Dry Forests ◽  
Protection Measures ◽  
Deforestation Rate

Abstract Background Fragmentation and deforestation are one of the greatest threats to forests, and these processes are of even more concern in the tropics, where the seasonal dry forest is possibly one of the most threatened ecosystems with the least remaining surface area. Methods The deforestation and fragmentation patterns that had occurred in Ecuadorian seasonal dry forests between 1990 and 2018 were verified, while geographic information systems and land cover shapes provided by the Ecuadorian Ministry of the Environment were employed to classify and evaluate three types of seasonal dry forests: deciduous, semi-deciduous, and transition. The study area was tessellated into 10 km2 hexagons, in which six fragmentation parameters were measured: number of patches, mean patch size, median patch size, total edge, edge density and reticular fragmentation index (RFI). The RFI was also measured both outside and inside protected natural areas (unprotected, national protected areas and protected forest). Moreover, the areas with the best and worst conservation status, connectivity and risk of disappearance values were identified by means of a Getis-Ord Gi* statistical analysis. Results The deforestation of seasonal dry forests affected 27.04% of the original surface area still remaining in 1990, with an annual deforestation rate of − 1.12% between 1990 and 2018. The RFI has increased by 11.61% as a result of the fact that small fragments of forest have tended to disappear, while the large fragments have been fragmented into smaller ones. The semi-deciduous forest had the highest levels of fragmentation in 2018. The three categories of protection had significantly different levels of fragmentation, with lower RFI values in national protected areas and greater values in protected forests. Conclusions The seasonal dry forest is fragmenting, deforesting and disappearing in some areas. An increased protection and conservation of the Ecuadorian seasonal dry forest is, therefore, necessary owing to the fact that not all protection measures have been effective.

Abundance of Panamanian dry-forest birds along gradients of forest cover at multiple scales

2009 ◽  
Vol 26 (1) ◽  
pp. 67-78 ◽  
Author(s):  
Jesse R. Lasky ◽  
Timothy H. Keitt
Keyword(s):  
Forest Cover ◽  
Multiple Scales ◽  
Spatial Scales ◽  
Habitat Associations ◽  
Forest Birds ◽  
Dry Forest ◽  
Forest Species ◽  
Dry Forests ◽  
Open Habitat ◽  
Forest Coverage

Abstract:Community structure and species’ abundances may be strongly correlated to patterns of forest cover, although such patterns are poorly known for tropical dry-forest birds, especially for those in Panamanian dry forests. Birds were distance-sampled during point counts in five dry-forest fragments in Panama. Distance from point count to forest edge and forest coverage at three spatial scales (500, 1000 and 2000-m radius) were compared as covariate predictors of the abundance of avian species and guilds. Each covariate was selected in at least two models of species or guild abundance. Abundance patterns were consistent with previously reported habitat associations for only two of seven open-habitat or forest-preferring species that showed forest cover-abundance relationships. Null models best described the abundance of all forest species and the subset of uncommon forest species. Thus many of these species appear insensitive to the forest-cover gradients studied. Total abundance of open-habitat-preferring species increased in dry forests with increasing forest coverage within 500 m, suggesting that the relationship between their abundance and vegetation structure are spatial-scale and habitat dependent. Nectarivores had lower abundance as forest cover within 1000 m increased, supporting previous claims that this group is tolerant of forest edges.

scholarly journals Landscape Structure and Seasonality: Effects on Wildlife Species Richness and Occupancy in a Fragmented Dry Forest in Coastal Ecuador

2021 ◽  
Vol 13 (18) ◽  
pp. 3762
Author(s):  
Xavier Haro-Carrión ◽  
Jon Johnston ◽  
Maria Juliana Bedoya-Durán
Keyword(s):  
Species Richness ◽  
Vegetation Index ◽  
Forest Cover ◽  
Normalized Difference Vegetation Index ◽  
Dry Forest ◽  
Wet Season ◽  
Mammal Species ◽  
Landscape Characteristics ◽  
Wildlife Species ◽  
Species Occupancy

Despite high fragmentation and deforestation, little is known about wildlife species richness and occurrence probabilities in tropical dry forest (TDF) landscapes. To fill this gap in knowledge, we used a Sentinel-2-derived land-cover map, Normalized Difference Vegetation Index (NDVI) data and a multi-species occupancy model to correct for detectability to assess the effect of landscape characteristics on medium and large mammal occurrence and richness in three TDF areas that differ in disturbance and seasonality in Ecuador. We recorded 15 species of medium and large mammals, distributed in 12 families; 1 species is critically Endangered, and 2 are Near-Threatened. The results indicate that species occupancy is related to low forest cover and high vegetation seasonality (i.e., high difference in NDVI between the wet and dry seasons). We believe that the apparent negative effect of forest cover is an indicator of species tolerance for disturbance. The three sampling areas varied from 98% to 40% forest cover, yet species richness and occupancy were not significantly different among them. Vegetation seasonality indicates that more seasonal forests (i.e., those where most tree species lose their leaves during the dry season) tend to have higher mammal species occupancy compared to less seasonal, semi-deciduous forests. Overall, occupancy did not vary between the dry and wet seasons, but species-specific data indicate that some species exhibit higher occupancy during the wet season. This research offers a good understanding of mammal species’ responses to habitat disturbance and fragmentation in TDFs and provides insights to promote their conservation.

scholarly journals Biodiversity of Algae and Cyanobacteria in Biological Soil Crusts Collected Along a Climatic Gradient in Chile Using an Integrative Approach

2020 ◽  
Vol 8 (7) ◽  
pp. 1047 ◽  
Author(s):  
Elena Samolov ◽  
Karen Baumann ◽  
Burkhard Büdel ◽  
Patrick Jung ◽  
Peter Leinweber ◽  
...  
Keyword(s):  
Species Richness ◽  
Coniferous Forest ◽  
Its Region ◽  
Small Subunit ◽  
Dry Forest ◽  
Temperate Climate ◽  
Integrative Approach ◽  
Small Subunit Rrna ◽  
Forest Region ◽  
Eukaryotic Microorganisms

Biocrusts are associations of various prokaryotic and eukaryotic microorganisms in the top millimeters of soil, which can be found in every climate zone on Earth. They stabilize soils and introduce carbon and nitrogen into this compartment. The worldwide occurrence of biocrusts was proven by numerous studies in Europe, Africa, Asia and North America, leaving South America understudied. Using an integrative approach, which combines morphological and molecular characters (small subunit rRNA and ITS region), we examined the diversity of key biocrust photosynthetic organisms at four sites along the latitudinal climate gradient in Chile. The most northern study site was located in the Atacama Desert (arid climate), followed by open shrubland (semiarid climate), a dry forest region (Mediterranean climate) and a mixed broad leaved-coniferous forest (temperate climate) in the south. The lowest species richness was recorded in the desert (18 species), whereas the highest species richness was observed in the Mediterranean zone (40 species). Desert biocrusts were composed exclusively of single-celled Chlorophyta algae, followed by cyanobacteria. Chlorophyta, Streptophyta and cyanobacteria dominated semiarid biocrusts, whereas Mediterranean and temperate Chilean biocrusts were composed mostly of Chlorophyta, Streptophyta and Ochrophyta. Our investigation of Chilean biocrust suggests high biodiversity of South American biocrust phototrophs.

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