Semi-humid Forests Research Articles

Unveiling the Dynamics of Canopy Transpiration: A Novel Model Integrating Stomatal and Aerodynamic Resistance in Semi-Humid Forests

Canopy–atmospheric water vapor output resistance (gs) is a key parameter in researching forest canopy transpiration. It is important for quantifying the water vapor exchange in forest ecosystems. However, the method by which gs is determined has been controversial, and it cannot precisely represent water vapor exchange. This study aimed to develop a model to quantify the water vapor resistance between the canopy and the atmosphere in Platycladus orientalis (P. orientalis) forests using sap flow and meteorological factors monitoring data. The resistance model was constructed using the relationship between canopy stomatal resistance (gc) and aerodynamic resistance (ga) from the mechanism perspective, and sap flow data and measurements of meteorological variables were used to model the stomatal and aerodynamic resistance of the canopy. The results indicate that the canopy-atmospheric water vapor output resistance was closer to the measured values and showed a unimodal curve in the diurnal scale, and this change could provide more accurate measurements of tree transpiration. At the same time, the canopy-atmospheric water vapor output resistance was strongly influenced by wind speed and PAR when 0.2 m/s < u < 0.4 m/s (R2 = 0.871, p < 0.01). The stomatal and aerodynamic resistance were also both strongly influenced by wind speed, with the proposed model achieving a high degree of fit (R2 = 0.949, p < 0.01), providing a new tool for analyzing forest transpiration. This research provides a new perspective and technical reference for clarifying the mechanism of forest canopy water output.

Changes in Soil Organic Carbon Density and Its Response to Climate Change and Human Activities Before and After the Grain for Green Project on the Loess Plateau

Accurately assessing the changes in soil organic carbon storage （SOCS） before and after the Grain for Green Project （GFG） in the Loess Plateau （LP） and exploring the relationship between its spatial and temporal distribution and the influencing factors were important references for the development of regional recycling as well as the formulation of ecological protection policies. Based on the data of climate, human activities, and SOCD in the surface （0-20 cm） and deep （0-100 cm） soil before and after GFG in the LP from 2001 to 2020, we investigated the changes in SOCD at different spatial and temporal scales by using the methods of trend analysis, the kriging method, and variance partitioning analysis. The results showed that： ① Before and after the GFG, the surface SOCS of the whole region increased by 8 338.7×104 t； the deep SOCS increased by 1 160.02×104 t. ② In each bioclimatic subregion, the whole-region average SOCD of Ⅰ （Semi-Humid Forest Region）, Ⅱ （Semi-Humid Semi-Arid Forest and Grassland Region）, and Ⅲ （Semi-Arid Typical Grassland Region） showed a significant increasing trend, with a decreasing trend in Ⅳ （arid semi-arid desert grassland area） and Ⅴ （arid desert area）. ③ The average surface SOCS increase in different ecosystems was ranked as follows： cropland > grassland > woodland > shrubs > bare land and sparse vegetation. The deep soil increase was ranked as follows： grassland > cropland > woodland > shrubs > bare land and sparse vegetation. ④ Climate factors were the most important driving factors for changes in SOCD； the annual average temperature and precipitation were significantly positively correlated with changes in SOCD. The results of the study could provide data support for regional ecological management and land use policy formulation to promote high quality development of the ecological environment in the LP.

Forest cover, tree structure, and fruit size as predictors of fruit consumption by birds in two tropical trees from southern Mexico

We evaluate the effect of some variables related to fruit morphology, tree structure, and forest cover on fruit consumption by birds in the tree species Conostegia xalapensis (Melastomataceae) and Bursera simaruba (Burseraceae), in a semi-humid forest of southern Mexico. Foraging observations were made in 20 trees per species from November 2020 to June 2021. We recorded a total of 18 and 22 bird species consuming the fruits of B. simaruba and C. xalapensis, respectively. Flycatchers preferred fruits of B. simaruba, while thrushes largely consumed fruits of C. xalapensis. For large birds, crop size and foliar height diversity were the most influential variables in the removal of B. simaruba fruits, while small birds were positively correlated with the foliar coverage. For C. xalapensis, forest cover negatively influenced fruit consumption by large birds, while the fruit polar diameter had a positive effect on fruit consumption by small birds. Fruit consumption of C. xalapensis by specialist birds showed a positive relationship with forest cover, while the generalists showed a negative relationship. Decreased fruit removal was observed for B. simaruba by both specialist and generalist birds in forest landscapes. Our results can help understand the drivers of the frugivore-plant relationship in semi-humid tropical forests.

Carbon pools in forest systems and new estimation based on an investigation of carbon sequestration

Forests, the ancient wooden giants, are both symbols of natural beauty and reservoirs of carbon stocks. The current climate crisis has created an urgent need for an in-depth study of forest ecosystems and carbon stocks. Based on forest inventory data from field surveys and four bioclimatic zones [Zone 1 (Z1, humid forest), Zone 2 (Z2, semi-humid forest), Zone 3 (Z3, semi-humid to semi-arid forest-grassland), and Zone 4 (Z4, semi-arid typical grassland)], two methods [Method 1 (M1) and Method 2 (M2)] were used to estimate carbon stocks in forest ecosystems in Shaanxi Province, China, and explored the spatial patterns of carbon pools and potential influences. The total forest ecosystem carbon pool amounted to 520.80 Tg C, of which 53.60% was stored aboveground, 17.16% belowground, and 29.24% in soil (depth of 0–10 cm). Spatially, there were marked north-south gradients in both biomass (Z2 > Z3 > Z1 > Z4) and soil organic carbon densities (Z1 > Z2 > Z3 > Z4). The differences between aboveground and belowground biomass carbon density across broadleaf, needle-leaf, and broadleaf and needle-leaf mixed forest were not pronounced, while soil organic carbon density had the order of broadleaf (18.38 Mg C/ha) > needle-leaf (11.29 Mg C/ha) > broadleaf and needle-leaf mixed forest (10.33 Mg C/ha). Under an ideal scenario that excludes external factors, mainly forest growth, the sequestration potential of forest biomass by 2032 was estimated by M1 as 85.43 Tg, and by M2 to be substantially higher at 176.21 Tg. As of 2062, M1 estimated 155.97 Tg of sequestration potential for forest biomass. The spatial patterns of forest biomass and soil carbon density were closely related to climatic factors, and these relationships allowed the spatial division into two distinct climatic regions. Moreover, biomass carbon density was significantly correlated with the normalized difference vegetation index, soil silt, and elevation. This study provides key information for promoting the strategic shift from light-green to deep-green forest systems in Shannxi Province and updates the estimation methods of forest ecosystems’ carbon pools based on field surveys.

Four new deciduous species of Hyperacanthus (Rubiaceae: Gardenieae) from western Madagascar: the sofikomba alliance

SummaryThe genus Hyperacanthus comprises 11 species, nine in Madagascar and two in Africa, although many Madagascan species remain undescribed. All Madagascan species of Hyperacanthus are evergreen trees occurring in humid and semi-humid forest. Four deciduous species occur in the dry forests of northern, western, and southern Madagascar but are unknown to science. These four species, collectively and informally referred to as the sofikomba alliance, are described here: H. decaryi, H. piliformis, H. septentrionale and H. sofikomba. Three of the four species are illustrated and all four are mapped. A key to species, species descriptions, other key taxonomic information, and preliminary conservation assessments are also provided.

VULNERABILIDAD DE ESPECIES FORESTALES DE LA PENÍNSULA DE YUCATÁN ANTE FACTORES CLIMÁTICOS Y ANTROPOGÉNICOS

<p><strong>Background</strong>: The Yucatan Peninsula is covered mainly by semi-humid forests associated with karstic zones. These landscapes show high rates of endemism, and although they are resilient ecosystems, climatic variations place them as highly susceptible areas to climate change. <strong>Objective:</strong> To identify environmental and anthropogenic risk factors in the semi-humid forests of the Yucatan Peninsula, and to evaluate the vulnerability to climate change of 25 forest species with economic importance in this region. <strong>Methodology:</strong> A multi-criteria analysis was carried out to rank edaphic and climatic variables, changes in potential distribution due to climate change, species density and growing rate. These variables were integrated into a matrix and each variable was valued from 0 to 4, weighted between parameters, the higher the value, the greater the susceptibility. Four percent of the species were classified into the high-risk susceptibility and 84 % as medium risk and the rest as low. These species have a low density per hectare, have a restricted distribution, are slow growing and are over shallow soils. <strong>Implications: </strong>Species that can develop in a wide range of environmental conditions and have rapid growth rates were less susceptible to the risk factors analyzed here. <strong>Conclusions:</strong> The greatest risk factor was due to the effect of climate change, followed by the proximity to the Caribbean coast and the type of soil, which suggests that more conservation actions for forest species are needed, which will also ensure the provision of environmental services to human populations.</p>

WOODY AND SEMI-WOODY PLANTS, WILD AND NATIVE TO DRY AND SEMI-HUMID FORESTS FROM THE ÁREA DE PROTECCIÓN DE FLORA Y FAUNA MESETA DE CACAXTLA, SINALOA, MÉXICO

<p><strong>Background. </strong>Plant catalogues are basic to propose and manage natural protected areas. Through those censuses plans and conservation strategies are developed, plus comparisons can be made over time. Updated floristic listings are urgent in tropical forests due to the threats to their biodiversity. <strong>Objective. </strong>Present a structured listing by family, genus and species, which quantifies the hierarchical relations of genera-species and family-genera while arranging life-forms and including species with endangered status recorded in national (NOM-059 SEMARNAT 2010) and international (Red list, UICN) legislation of woody and semi-woody plants from dry and semi-humid forest from the Área de Protección de Flora y Fauna Meseta de Cacaxtla, Sinaloa, México (APFFMC). <strong>Methodology. </strong>Published studies about the site were reviewed, selecting the indigenous species with secondary growth, excluding the invasive, naturalized, cultivated, ornamental ones, collating different online sites, specialized bibliography and consulting specialists. Regarding the nomenclature different sources and databases were employed. Through field trips, the presence of taxa was corroborated and new registers were included. The listing was sorted alphabetically. <strong>Results.</strong> 60 families, 223 genera and 389 species were recorded. Fabaceae was the family with the highest taxa richness, with 44 genera and 75 species, followed by Malvaceae (19/31), Euphorbiaceae (12/34), Asteraceae (10/17), Cactaceae (9/21) and Apocynaceae (8/10). A low number of 13 genera and 12 families gathered five or more species and genera respectively. On the other hand, a high quantity of 210 genera and 48 families presented four or less taxa. The most diverse genera were <em>Croton</em> (12 species), <em>Bursera</em> (8), <em>Solanum</em> (7), <em>Ficus</em> and <em>Randia</em> (6); <em>Opuntia</em>,<em> Merremia</em>, <em>Euphorbia</em>, <em>Lonchocarpus</em>, <em>Mimosa,</em> <em>Senna, Jatropha </em>and <em>Sideroxylon</em> (5). The tree category grouped 146 species, followed by shrub (114), sub-shrub (54), vine (51), succulent and semi-succulent (21) and parasitic (3). According to the NOM 059 SEMARNAT-2010 endangered species list, five species were included in the Amenazadas (A) category and two Sujetas a protección especial (Pr). The red list (UICN) comprehended 173 species for the Natural Protected Area (ANP). In the Least concern category (LC) 155 taxa were counted, Near threatened (NT) with four, Vulnerable (V) seven and Endangered (EN) again seven. <strong>Implications.</strong> A renewed listing of alien, native, woody and semi-woody species from dry and semi-humid forests of the APFFMC, is crucial for its contribution to a proper management and decision taking in the ANP. 94 taxa names were updated. At family level, the inclusion of Sterculiaceae into Malvaceae was the most significant change. <strong>Conclusions. </strong>The taxonomic richness concentrated inside the APFFMC, whose surface is inferior to 1% of the state, oscillates between 10.41 and 13.93% of the species; 19.95 and 22.80 % of the genera and 29.70 and 30% of the families reported in the state of Sinaloa, Mexico.</p>

Ancient climate changes and Andes uplift, rather than Last Glacial Maximum, affected distribution and genetic diversity patterns of the southernmost mycoheterotrophic plant Arachnitis uniflora Phil. (Corsiaceae)

Arachnitis uniflora (Corsiaceae) is a mycoheterotrophic plant native to South America that grows in tropical semi-humid forests of Peru and Bolivia, in the temperate Andean-Patagonian forests of Argentina and Chile, and in the moorlands of Malvinas/Falkland Islands. This widely distributed and disjunct species offers the opportunity to explore the dynamics of evolutionary processes using phylogeographic approaches, spatio-temporal and paleodistribution reconstructions; these tools allow us to test how ancient geological events and climate changes occurred in the Miocene-Pliocene and how the more recent Pleistocene events affected diversification, demography, and genetic diversity patterns over space and time. We sampled 28 sites, covering the whole geographic range of Arachnitis uniflora . We amplified and sequenced the internal transcribed spacer (ITS), 18S rRNA, and 26S rRNA nuclear regions in 141 individuals, and the plastid 16S rRNA gene in a subset of 90 individuals. In order to reconstruct the evolutionary history of the species, we performed phylogeographic, dating analyses, spatio-temporal diffusion models, and species paleo-distribution projections. Arachnitis uniflora has an ancient origin and diversified during the Late Miocene, splitting into two genetic groups named the Northern and Patagonian groups. Haplotype diversification of both groups dated about late Miocene and early Pliocene. We detected demographic expansion at the early Pleistocene, and most diversifications and colonizations occurred before the LGM. Paleo-distribution modelling predicted few changes of the species distribution from 800 Mya to the present, showing only a range expansion at the east during the LGM. Four areas of high genetic diversity were identified suggesting refugial areas where the species persisted. Orogeny and climate changes promoted by the Andes uplift during the Late Miocene produced the main ancient genetic divergence due to the formation of the Arid Diagonal. Most diversification, colonizations, and demographic processes occurred from early Pliocene to the beginning of the Pleistocene before the Great Patagonian Glaciation, revealing a low influence of the LGM glaciations on the species evolutionary history. • First study on the evolutionary history of a mycoheterotrophic plant species • Genetic divergence in correlation with the formation of the Arid Diagonal • Andes uplift rather than Pleistocene glaciations were responsible for main diversifications. • Hotspots areas are coincident with those recovered for its fungal symbiont.

Intensification of water storage deficit in topsoil but not deep soil in a semi-humid forest after excluding precipitation for two years

Deep-rooted forest trees can potentially utilize moisture in deep soil to tolerate periods when growth is water limited. Black locust (R. pseudoacacia) is a deep-rooted forest species but the benefits of deep roots for water uptake under drought conditions are unclear. In this study, we assessed the effects of drought on water storage and the hydrological properties of soil at different depths. We performed a precipitation manipulation experiment continuously from June 2015 to November 2016 using mature R. pseudoacacia in the Loess Plateau region of China. The soil volumetric water contents were measured in the 0–4 m soil layer, as well as the soil hydrological properties comprising the soil bulk density (BD), total porosity, saturated hydraulic conductivity (Ks), and aggregate-associated organic carbon (OC) concentration in the 0–20 cm soil layer. The results showed that soil water storage deficit mainly occurred in the 0–1 m soil layer rather than in the 1–4 m layer after excluding precipitation for two years. Compared with the control, excluding precipitation for two years decreased the soil water storage in the 0–1 m soil layer by 18%. Precipitation exclusion also significantly decreased the soil Ks by 28% and total porosity by 17%, but increased BD by 20% in the 0–10 cm soil layer. In addition, precipitation exclusion significantly decreased the total soil OC concentration and macro- and micro-associated OC concentrations. Our results indicate that excluding precipitation for two years could potentially degrade the water conditions in the topsoil layer but not the deeper soil. These findings provide insights into water management and sustainability in semi-humid afforestation areas of the Loess Plateau region in China.

Aggregate binding agents improve soil aggregate stability in Robinia pseudoacacia forests along a climatic gradient on the Loess Plateau, China

The distribution of binding agents (i.e., soil organic carbon (SOC) and glomalin-related soil protein (GRSP)) in soil aggregates was influenced by many factors, such as plant characteristics and soil properties. However, how these factors affect binding agents and soil aggregate stability along a climatic gradient remained unclear. We selected the Robinia pseudoacacia L. forests from semi-arid to semi-humid of the Loess Plateau, China to analyze the plant biomass, soil physical-chemical properties, SOC and GRSP distribution in different sized soil aggregates. We found that from semi-arid to semi-humid forests: (1) the proportion of macro-aggregates (>0.250 mm) significantly increased (P<0.05), whereas those of micro-aggregates (0.250–0.053 mm) and fine materials (<0.053 mm) decreased and soil aggregate stability was increased; (2) the contents of SOC and GRSP in macro-aggregates and micro-aggregates significantly increased, and those in fine materials decreased; (3) the contribution of SOC to soil aggregate stability was greater than those of total GRSP and easily extractable GRSP; (4) soil properties had greater influence on binding agents than plant biomass; and (5) soil aggregate stability was enhanced by increasing the contents of SOC and GRSP in macro-aggregates and soil property was the important part during this process. Climate change from semi-arid to semi-humid forests is important factor for soil structure formation because of its positive effect on soil aggregates.

Changes in soil physical and chemical properties after short drought stress in semi-humid forests

The Loess Plateau region of China is under increasing water shortage due to declining soil water content after reforestation. Thus, assessing the changes in soils properties in reforested lands is critical for sustainable restoration of vegetation. We conducted a continuous rainfall manipulation experiment from June 2015 to November 2016 using mature black locust (Robinia pseudoacacia) on southern Loess Plateau of China. The soil hydrological properties, aggregate distribution and aggregate organic carbon (OC) and total nitrogen (N) concentrations were measured. Two years of drought stress caused a significant decline in saturated hydraulic conductivity and total porosity, but an increase bulk density in the 0–10 cm soil layer. The short drought stress significantly decreased soil aggregate stability due to a decline in macro-aggregate mass. Drought stress significantly decreased total soil OC concentration and macro- and micro-OC or N concentrations, but had no significant effect on total N concentration after two years of drought. Furthermore, the influence of short drought on soil hydrological properties, aggregate distribution and aggregate OC and total N concentrations was mainly evident at the depth of 10 cm. Our results indicated that short drought has the potential to damage soil properties. The results of this study could provide more insight into the sustainability of afforestation in semi-humid areas of China's Loess Plateau.

Sap flow of black locust in response to short-term drought in southern Loess Plateau of China

Soil water shortage is a major factor influencing the ecology and hydrology of vegetation in China’s semihumid Loess Plateau. However, few studies have experimentally assessed how expected changes in precipitation will affect sap flow in semihumid forest ecosystems. In this study, we measured the sap flow of black locust (Robinia pseudoacacia Linn.) under ambient and drought (induced by throughfall exclusion) conditions in 2015 and 2016, and investigated the relationship between stand transpiration and environmental factors in the semihumid China’s Loess Plateau. Throughfall exclusion significantly decreased sap flux density and stand transpiration by 39% and 28%, respectively, in 2016, which may have been due to the cumulative droughts effect from both 2015 and 2016. Throughfall exclusion caused a significant reduction in soil moisture, leaf area index (LAI), and stem diameter. Stand transpiration was positively correlated with LAI (P < 0.01), but precipitation and soil moisture did not correlate with stand transpiration at a daily timescale, suggesting that LAI can be used as a proxy for stand transpiration. Our results highlight that precipitation must be considered when planting black locust in semihumid regions. These findings provide basic information about the management of water resources and vegetation restoration in the semihumid China’s Loess Plateau and possibly other water-limited regions around the world.

The advertisement call of Stumpffia be Köhler, Vences, D'Cruze & Glaw, 2010 (Anura: Microhylidae: Cophylinae).

We describe the calls of Stumpffia be Köhler, Vences, D'Cruze & Glaw, 2010. This is the first call description made for a species belonging to the large-bodied northern Madagascan radiation of Stumpffia Boettger, 1881. Stumpffia is a genus of small (~9-28 mm) microhylid frogs in the Madagascar-endemic subfamily Cophylinae Cope. Little is known about their reproductive strategies. Most species are assumed to lay their eggs in foam nests in the leaf litter of Madagascar's humid and semi-humid forests (Glaw & Vences 1994; Klages et al. 2013). They exhibit some degree of parental care, with the males guarding the nest after eggs are laid (Klages et al. 2013). The bioacoustic repertoire of these frogs is thought to be limited, and there are two distinct call structures known for the genus: the advertisement call of the type species, S. psologlossa Boettger, 1881, is apparently unique in being a trill of notes repeated in short succession. All other species from which calls are known emit single, whistling or chirping notes (Vences & Glaw 1991; Vences et al. 2006).

Diet composition of nestlings and adults of the threatened Bolivian Swallow-tailed Cotinga Phibalura flavirostris boliviana (Aves: Passeriformes: Cotingidae) in Bolivia

The qualitative and quantitative composition of the nestling and adult diet of the threatened Swallow-tailed Cotinga Phibalura flavirostris boliviana was studied through the analysis of fecal samples. Nestling diet consisted of 62% fruit and 38% insects but varied according to the nestling age. The diet of adults was made up of 89% fruit and 11% insects. The fruit eaten came primarily from the trees Schefflera morototoni, Hyeronima moritziana and Ocotea cuprea. Most insects in the fecal samples were winged-species of the orders Hymenoptera and Coleoptera. This species relied mostly on fruiting trees from semi-humid forest fragments and isolated trees on mountain savannas. Thus, management plans for this bird should consider the conservation of these habitats. Â

Carbon Stocks in Organic Coffee Systems in Chiapas, Mexico

Agroforestry systems contribute to the maintenance of ecosystem functions, especially agrisilvicultural systems such as shade coffee systems. However, the role of organic crops to store carbon has been scarcely investigated. This study aimed to quantify carbon stocks in organic polyculture coffee plantations, non-organic polyculture plantations, and organic Inga spp.-shaded coffee systems in northern Chiapas, Mexico. Vegetation inventories were carried out in 1,000 and 100 m 2 circular plots from six agroforestry communities. Carbon stocks were estimated from living biomass and roots through allometric formulas; dead biomass and soil organic matter (0- 0.3 m- in depth) were collected, dried, weighted and processed for laboratory analysis. Firstly, results showed that living biomass contributed about 30% of total carbon; soil organic carbon particularly contributed between 56 and 70%; while dead organic matter represented between 3 and 5% of total carbon in the system. Organic polyculture coffee plantations stored significantly more carbon in soil (0.1-0.3 m in depth) and tree biomass than non-organic polyculture coffee plantations. These stocks were intermediate in organic Inga spp. - shaded coffee system. Secondly, dead organic matter was statistically similar between systems. Thus, organic polyculture coffee plantations, non-organic polyculture, and organic Inga spp.-shade system stored 194.7, 134.9, and 154.3 Mg C ha -1 of total carbon, respectively. In the same order, these systems stored in live aboveground biomass 57.5, 53.0, and 46.9 Mg C ha -1 , respectively. Dead organic matter had similar amounts of C stored in the three studied systems (6.3 Mg C ha -1 ). The amounts of total carbon stocks in organic coffee were higher than those reported for others in coffee plantations in Central America and, particularly, similar to some dry and semi-humid forests and other agrisilvicultural systems in Mexico. The results highlight the importance of coffee, especially organic coffee to provide the environmental function of carbon sequestration.

Subtropical montane evergreen broad-leaved forests of Yunnan, China: diversity, succession dynamics, human influence

This paper integrates studies on the natural subtropical montane evergreen broad-leaved forests (EBLFs) and secondary succession of the forests and plantations in Yunnan, to provide a basis for evaluating the sustainability of the forests in the mountain ecosystems of Yunnan, China. The EBLFs include mid-montane moist, monsoon, and semi-humid categories. The monsoon EBLF yielded the highest indices of the Shannon-Wiener H, Equitability J, Simpson D and Fisher’s alpha, followed by the mid-montane moist EBLF, then by the semi-humid forest. Since human uses have varied widely, the plant communities ranged from pioneer deciduous broad-leaved and/or pioneer coniferous stands to late-successional evergreen broad-leaved stands. The secondary succession pathways were from pioneer deciduous stands of Alnus accompanied by stands of pioneer coniferous Pinus and Keteleeria, through broad-leaved and coniferous mixed stands, to late-successional evergreen broad-leaved forests of Cyclobalanopsis and Castanopsis. In Yunnan, the EBLF is commonly replaced by plantations of exotic fast-growing Eucalyptus to produce industrial wood, oil, pulp and fuel. The result has been reduced plant diversity, and great loss of soil nutrients by erosion and runoff, as compared to the EBLF. Seventy-six plant species in the area have been ranked as critically endangered, endangered, or vulnerable. Their condition is seen as largely attributable to habitat loss or degradation. A clear understanding of ecological features and succession pathways of the EBLF can lead to more effective conservation and management of these fragile forests and the mountain ecosystems.

Assessing land‐atmosphere coupling using soil moisture from the Global Land Data Assimilation System and observational precipitation

Precipitation analysis and soil moisture from the Global Land Data Assimilation System (GLDAS) are used to assess the land‐atmosphere coupling in boreal summer. Correlations between antecedent soil moisture and precipitation suggest that regions of strong land‐atmosphere coupling lie mainly in arid to semiarid transition zones or in semihumid forest to grassland transition zones. They consist of central Eurasia, the region from Mongolia to northern China, southwest China, the Sahel, the northern continental United States, and southern Europe. It is found that over these regions, positive soil moisture feedback accounts for typically 10–20% of the variance of monthly precipitation anomalies with the feedback efficiency of the order of 0.3–0.9 mm month−1 (0.1 standardized soil moisture)−1. While soil moisture feedback is dominated by the positive sign, negative feedback may exist in some areas, such as India and the western part and Quebec province of Canada. Generally, the land‐atmosphere coupling strength estimated from the GLDAS data agrees well with those from the observational soil moisture in Illinois and the European Centre for Medium‐Range Weather Forecasts 40‐year reanalysis (ERA‐40) soil moisture product. Physical mechanisms responsible for the findings are further discussed. This study provides a Northern Hemisphere distribution of the land‐atmosphere coupling strength, which can be used to test the model simulations on monthly to seasonal time scales.

Diet and Feeding Ecology of Ateles chamek in a Bolivian Semihumid Forest: The Importance of Ficus as a Staple Food Resource

We describe temporal patterns of food consumption by Peruvian spider monkeys (Ateles chamek) in a semihumid forest in lowland Bolivia. We assessed dietary composition in relation to temporal variation in abundance, duration, and synchrony of different food items in their home range. We collected data from September 2003 to September 2004, in the forestry concession La Chonta, Department of Santa Cruz. Throughout the period of detailed feeding data collection (February-September 2004), Ateles chamek used Ficus as a staple food resource. Figs constituted almost 50% of their diet in terms of total time spent feeding, and subjects consumed them to a great extent even during times of high overall food availability. This is contrary to the general expectation that for Neotropical frugivores, Ficus is a fallback food in times of fruit scarcity, rather than a staple food resource. Surprisingly, despite being considered ripe fruit specialists, Ateles chamek spent 18% of their feeding times eating unripe figs. Ateles chamek consumed unripe figs all through the year, including periods when ripe figs and other ripe fruit were abundant. We identify other important fallback foods for Ateles chamek in the forest, in particular the ripe fruit of Myrciaria sp.

Multidisciplinary approach for paleoenvironmental reconstruction in loess-paleosol studies of the Darai Kalon section, Southern Tajikistan

The available data on the loess-paleosol formation in South Tajikistan illustrate the completeness of climatostratigraphic records. However, studies with a multidisciplinary approach have not been practically used for paleoenvironmental reconstructions. This study partially corrects the lack of data on paleolandscape evolution in the loess area of Pamir and Tien Shan piedmonts. Darai Kalon serves as a key section embracing the upper part of the Matuyama Chron and the entire Brunhes Chron. High resolution magnetic susceptibility record shows that during the Brunhes epoch the climate cycles reflected by the Central Asian loess-paleosol succession can be correlated to the deep-sea oxygen isotope curve. The combination of pedological and palynological material is particularly useful for mutual interpretation. Lithological and mineralogical data essentially extend our understanding of pedogenetic and paleoclimatic dynamics. The tendency of soil and paleoenvironmental evolution recorded in the Darai Kalon section can be associated with subtropical semi-humid forest and forest-steppe landscapes. The variation of paleoclimatic parameters and paleovegetation type are characteristic of the contemporary vertical zone of Cinnamon Soils.

Wild pejibaye (Bactris gasipaes Kunth var. chichagui) in Southeastern Amazonia

The geographical distribution and morpho-genetic variation of wild and domesticated populations of a crop species are essential information for identifying a center of origin. The pejibaye (Bactris gasipaes Kunth) is the only domesticated neotropical palm, whose starchy-oily fruits are subsistence products and whose heart-of-palm is an expanding agribusiness. The origin of pejibaye is unresolved, but probably will be found in the distribution of type 1 B. gasipaes var. chichagui in southwestern Amazonia. A new area of occurrence of this type is reported around São Felix do Xingu, Pará, Brazil, 52°41' W 6°34' S, about 600 km northeast of the eastern-most known population, in central Mato Grosso, Brazil. The plants of this population are slightly less robust than other type 1 plants and have small fruit bunches (60-70 fruit), small fruit (0.45 g and 10 by 9 mm) and seed (0.23 g and 6.5 by 7.4 mm), all smaller than previous descriptions. Although this find is disjunct from earlier reports, it is unlikely that other populations are absent between it and central Mato Grosso, expanding type 1 var. chichagui's distribution by 30% and redefining it as a typical element of the transition between humid and semi-humid forests across southern Amazonia, rather than an Andean element expanding into the region.