Subtropical Deciduous Forest Research Articles

<i>Cestrum amithii</i> (Solanaceae), nueva especie de San Luis Acatlán, Guerrero, México

Background: One specimen collected in Yoloxóchitl (San Luis Acatlán, Guerrero, Mexico) was initially reviewed by Michael Nee, who suggested that it could be a new species of the genus Cestrum, and commissioned to the first author to describe it. Questions: Do Cestrum populations from San Luis Acatlán, Guerrero, correspond to a new species for science? Studied species: Cestrum sp. nov. Study site and dates: Yoloxóchitl, Municipality of San Luis Acatlán, Guerrero; 2023-2024. Methods: The specialized bibliography on the genus Cestrum was examined, from which a list of species with similar morphology to the studied species was compiled, all of which were examined using high resolution digital photographs. A botanical exploration was carried out, locating three populations. A morphological analysis was conducted with the collected material. Results: Cestrum amithii is defined as a new species for science. This new species presents many differences in terms of floral and foliar characters from the other species of the genus. The most outstanding is its spathaceous calyx, which is markedly asymmetrical and large, with evident ribs and two to three lobes. C. amithii is known only from Yoloxóchitl, Guerrero, where it grows in sub-deciduous tropical forest vegetation, at elevations of 530-630 m asl. It is associated with seasonal streams and creeks. Conclusions: With this new discovery, the number of Cestrum species in the flora of Guerrero state increases to 16.

Contrasting temperature and light sensitivities of spring leaf phenology between understory shrubs and canopy trees: Implications for phenological escape

Spring leaf phenology influences plant fitness and is highly sensitive to environmental changes. The spring phenological escape hypothesis posits that deciduous understory plants generally leaf out earlier than canopy trees to access a period of high light before the canopy closes. However, plants in different forest layers may respond differently to climate warming, which could lead to phenological mismatch between the understory and canopy species. Therefore, exploring the phenological sensitivities of plants from different forest layers is crucial for anticipating the effects of climate-driven phenological shifts. However, these types of studies are still scarce. Here, we conducted a twig experiment in climate chambers for eight tree species and seven shrub species growing in subtropical deciduous forests in the Shennongjia Mountains, central China. Specifically, we set up three treatments (control, warming, and shading) for five weeks to test the responses of the timing of bud burst and leaf unfolding, and the duration of bud development to different temperatures and light intensities. For shrubs, bud burst and leaf unfolding occurred earlier and the duration of bud development was shorter than these of trees. For both shrubs and trees, warming significantly advanced the timing of leaf unfolding and shortened the duration of bud development. Shading significantly delayed the timing of bud burst for both shrubs and trees. Shading also delayed the timing of leaf unfolding and lengthened the duration of bud development for trees, but did not significantly influence the two phenological metrics for shrubs. Tree phenology, as measured by all three metrics, was more sensitive to temperature than was shrub phenology. The timing of bud burst of shrubs was slightly more sensitive to light than that of trees. Our results indicate that shrubs leaf out earlier than trees in the same forest, which allows understory species to take advantage of the high-light resources before canopy closure. However, in our study, trees were more responsive to warming temperatures, suggesting that spring warming could advance canopy closure relative to shrub leaf phenology, potentially resulting in phenological mismatch between understory shrubs and canopy trees.

Pineapple cultivation under tree canopies of ancestral agroforests in Mexico

Mexico’s contemporary cultivation of pineapple, the king of tropical fruits, depends on intensive monoculture which negatively impacts the environment and human health. This represents a regression in history, as pineapple was traditionally cultivated in agroforests, which preserve the structural characteristics and ecological processes and functions of natural ecosystems. Some of these agroforestry systems remain, having been conserved for centuries by Indigenous and mestizo communities, particularly in the states of Jalisco and Nayarit, showcasing the sustainability and resilience of agroforestry. Unlike modern monoculture, pineapple agroforests incorporate diverse plant species to improve biodiversity and reduce disease, integrating pineapple with various woody species native to the subdeciduous tropical forest. They also provide shade and preserve forest cover, and limit the use of machinery, maximising the use of traditional knowledge and local technologies. The resulting agroecosystems not only sustain pineapple production but also yield additional products such as fruits, coffee, wood and fodder, contributing to food sovereignty and self-sufficiency. Despite the benefits of pineapple agroforests, they remain largely unknown at national and international levels, highlighting a need for greater recognition and support. This requires more data on the costs of establishing pineapple agroforests, as the costs are currently unclear. To encourage policymakers to promote the conservation and maintenance of pineapple agroforests, the article provides insight into their ecological and cultural significance and emphasises the importance of valuing and preserving ancestral agroforestry practices.

Taxonomic study of the tribe Onitini Laporte, 1840 (Coleoptera: Scarabaeidae: Scarabaeinae) from Northern Pakistan

We provide occurrence records of the members of dung beetle's tribe Onitini from the northern parts of Pakistan, including Gilgit-Baltistan, Khyber Pakhtunkhwa Province and Islamabad Capital Territory. This study is based on extensive field sampling from different ecological biomes including Alpine Meadows, the Sub-Alpine Zone, Mountain Temperate Forest, and Subtropical Deciduous Forest. As a result, we report six species under two genera of tribe Onitini: Onitis falcatus, O. lama, O. philemon, O. subopacus, O. virens, and Cheironitis arrowi. The genus Cheironitis is recorded for the first time from northern parts of Pakistan. We provide photographs of the dorsal and ventral habitus, diagnosis, distribution maps and identification keys to known genera and species in the tribe Onitini from Pakistan.

Spatial patterns and determinants of nitrogen composition in the trunk xylem sap of tree species from tropical to temperate forests

Trunk xylem sap nitrogen (N) composition can provide key information for interpreting tree N transport strategies in a changing environment. However, there remains poorly explored to properly depict the spatial patterns and determinants of the xylem sap N composition in different tree species across climate zones. Here, we analyzed the trunk xylem sap N of dominant tree species from tropical to temperate forests in eastern China. The random forest (RF) approach was used to quantify the relative importance of biotic and abiotic variables in driving the spatial patterns of the trunk xylem sap N composition. The concentration ranges of total N (TN), ammonium (NH4+) and nitrate (NO3−) in the trunk xylem sap were 0.37–37.23, 0.01–2.60 and 0.01–0.49 mM, respectively. Dissolved organic nitrogen (DON) was the main component of TN in the xylem sap of forest trees, accounting for 83.4 ± 3.6%, followed by NH4+ (11.8 ± 3.2%) and NO3− (4.8 ± 1.3%). In addition, the TN and NH4+ concentrations increased from the tropical rainforest and then decreased to the northern temperate forest, with a peak in the subtropical deciduous forest in the middle-latitude climatic transition zone. The NO3− concentration in the temperate forest was higher than that in other forests, regardless of coniferous and broad-leaf forests. Tree species was the key factor affecting the spatial TN patterns, whereas soil pH primarily and conversely determined the spatial NH4+ and NO3− patterns. Together, tree characteristics and soil properties were the most important factors affecting the spatial patterns of xylem sap N composition. These findings provide new insights into N cycling within forest trees and have implications for better understanding the adaptation to global changes in forest ecosystems.

Prediction of forest fire susceptibility applying machine and deep learning algorithms for conservation priorities of forest resources

Periodic forest fires occur in sub-tropical deciduous forest of Ayodhya hill region which is extended part of Eastern Ghats Mountain Range (India). This forest provides diverse ecosystem services (mostly non timber forest products)to tribal and non-tribal people throughout the year. The main objective of this study is to demarcate the accurate forest fire susceptibility zones applying three relevant machine learning models i.e., Random Forest (RF), Multivariate Adaptive Regression Splines (MARS) and Deep Learning Neural Network (DLNN). In this research, more than 300 hundreds historical forest fire events along with 14 forest fire predictors have been considered. DLNN model has the highest efficacy (AUC = 0.925). Features of DLNN are instinctively presumed and optimally tuned for required outcomes. Applied models explicitly examined that the north western and eastern segments of Ayodhya hill are highly susceptible for forest fire due to its physical and social complexity. DLNN model investigates that total 18% areas of Ayodhya hill have come under very high susceptible zone. The forest fire incidents are taken place during March to May because of the effect of high temperature, poor moisture content and existence of high fuel woods. Both the machine and deep learning techniques have been applied first time in this dry deciduous forest belt and models indicated high accuracy and precision which is harmonized with ground reality. This study will definitely help the local government to take proper management and conservation strategies for sustainable forest resources conservation along with improvement of livelihood of forest and forest fringe dwellers.

Effects of Trunk Distance and Rainfall on Throughfall and Associated Chemical Alterations within a Subtropical Deciduous Forest

Throughfall makes up the major portion of understory rainfall, and thereby plays a vital role in regulating the hydrological and biogeochemical processes in forest ecosystems. The aim of this study was to explore the alterations in throughfall and the associated chemical composition (Ca2+, Na2+, K+, Mg2+, H+, SO42−, NO3−, Cl−, and F−) under Quercus acutissima Carruth. and Broussonetia papyrifera (L.) L’Her. ex Vent. trees, in relation to trunk distance and rainfall characteristics. Event-based measurements were carried out from April to December 2018 in a subtropical forest of eastern China. The throughfall amount (TF) and throughfall ratio (TF%) of Q. acutissima (35.7 mm, 83.0%) were higher than those of B. papyrifera (32.1 mm, 74.7%). Although no significant species differences in the ion concentrations of throughfall were detected, almost all ions (Ca2+, Na2+, K+, Mg2+, H+, SO42−, NO3−, and Cl−) were enriched after passing through the canopies of the two tree species. TF and TF% increased with increasing distance from the trunk, while the concentrations of most ions in throughfall increased, since the trunk was approximated. Regression analysis and redundancy analysis revealed that rainfall amount, duration and intensity exerted significant impacts on throughfall generation and ion concentrations, and the antecedent dry period had a notable influence only on ion concentrations. Our findings indicated that forest canopy and rainfall characteristics play an important role in the alterations in throughfall and the associated chemical compositions.

Combining the Effects of Global Warming, Land Use Change and Dispersal Limitations to Predict the Future Distributions of East Asian Cerris Oaks (Quercus Section Cerris, Fagaceae) in China

Species shift their ranges in response to climate change (CC). However, they may not be able to track optimal conditions as soon as possible, due to limited dispersal ability or habitat fragmentation, caused by land use and land cover change (LULC). This study aimed to explore the combined impacts of CC, LULC and dispersal limitations on the future range dynamics of Quercus acutissima Carruth., Q. variabilis Blume and Q. chenii Nakai, three dominant Cerris oak tree species in warm-temperate and subtropical deciduous forests of China. We used the Maximum Entropy (Maxent) algorithm to predict the suitable habitats for the years 2050 and 2070, under three representative concentration pathways (RCPs). Habitat fragmentation patterns were examined to assess the influence of LULC. Two migration scenarios (full- and partial-migration) were compared to evaluate the effect of dispersal limitations. We found that annual precipitation (AP), minimum temperature in the coldest month (MTCM) and temperature seasonality (TS) play a key role in determining the present distributions of Q. chenii, while AP, MTCM and annual mean temperature (AMT) contribute the most to the distribution models of Q. variabilis and Q. acutissima. For all the three species, LULC will increase the level of habitat fragmentation and lead to the loss of core areas, while limited dispersal ability will restrict the accessibility of future potentially suitable habitats. Under the scenarios of CC and LULC, the suitable areas of Q. chenii will decrease sharply, while those of Q. variabilis in South China will become unsuitable. Our findings highlight the importance of considering dispersal ability, as well as land use and land cover change, for modeling species’ range shifts in the face of global warming. Our study also provides vital information for guiding the management of East Asian Cerris oaks in China; Q. chenii should be listed as a species requiring priority protection, and the threatened habitats of Q. variabilis should be protected to buffer the impacts of CC and LULC.

Exploring the stemflow dynamics and driving factors at both inter‐ and intra‐event scales in a typical subtropical deciduous forest

AbstractNumerous efforts have been made to understand stemflow dynamics under different types of vegetation at the inter‐event scale, but few studies have explored the stemflow characteristics and corresponding influencing factors at the intra‐event scale. An in‐depth investigation of the inter‐ and intra‐event dynamics of stemflow is important for understanding the ecohydrological processes in forest ecosystems. In this study, stemflow volume (FV), stemflow funnelling ratio (FR), and stemflow ratio (F%) from Quercus acutissima and Broussonetia papyrifera trees were measured at both inter‐ and intra‐event scales in a subtropical deciduous forest, and the driving factors, including tree species and meteorological factors were further explored. Specifically, the FV, FR and F% of Q. acutissima (52.3 L, 47.2, 9.6%) were lower than those of B. papyrifera (85.1 L, 91.2, 12.4%). The effect of tree species on FV and F% was more obvious under low intensity rainfall types. At the inter‐event scale, FV had a strong positive linear correlation with rainfall amount (GP) and event duration (DE) for both tree species, whereas FR and F% had a positive logarithmic correlation with GP and DE only under high‐intensity, short‐duration rainfall type. FR and F% were mainly affected by wind speed and the maximum 30‐min rainfall intensity under low‐intensity, long‐duration rainfall type. At the intra‐event scale, for both tree species, the mean lag time between the start of rainfall and stemflow was the shortest under high‐intensity, short‐duration rainfall type, while the mean duration and amount of stemflow after rain cessation were the greatest under high‐amount, long‐duration rainfall type. The relationship between stemflow intensity and rainfall intensity at the 5‐min interval scale also depended greatly on rainfall type. These findings can help clarify stemflow dynamics and driving factors at both inter‐ and intra‐event scales, and also provide abundant data and parameters for ecohydrological simulations in subtropical forests.

A new epigean species of ricinuleid of the genus Pseudocellus (Arachnida: Ricinulei: Ricinoididae) from a tropical sub-deciduous forest in Oaxaca, Mexico

A new species of epigean ricinuleid of the genus Pseudocellus Platnick, 1980 is described from a tropical sub-deciduous forest in Oaxaca, Mexico. The species is described based on adult males and females, protonymphs, deutonymphs and tritonymphs: Pseudocellus valerdii sp. nov. This is the second species described from the state of Oaxaca. The total number of described species of Pseudocellus from Mexico increases to 20, having the highest species diversity of known ricinuleids worldwide.

Haemosporidian prevalence, parasitaemia and aggregation in relation to avian assemblage life history traits at different elevations

The transmission of vector-borne protozoa such as parasites of the Order Haemosporida is dependent on both biotic and abiotic factors such as host life history traits and environmental conditions. This study aimed to identify the variables that determine haemosporidian prevalence, parasitaemia and aggregation within the context of elevation and avian life history traits in Central Veracruz, Mexico. We sampled 607 birds from 88 species; we used microscopy and the mtDNA cytochrome b gene to detect parasites. We found an overall prevalence of 32.3%. Haemosporidian prevalence was 21.6% in tropical sub-deciduous forest (at sea level), 38% in tropical deciduous forest (265 m above sea level (asl)), 19.4% in montane cloud forest (1630 m asl), and 51.7% in pine-oak forest (2790 m asl). The prevalence of each parasite genus was strongly influenced by elevation (a proxy of habitat type). Plasmodium showed the highest prevalence at low elevation. Haemoproteus increased in prevalence with elevation. Leucocytozoon displayed the highest prevalence at the highest elevation (pine-oak forest). Haemoproteus spp. and Leucocytozoon spp. prevalences were higher in open cup than in closed nests. Haemoproteus prevalence and haemosporidian parasitaemia were lower in solitary birds than birds with pairing and gregarious behavior. Haemosporidian aggregation decreased with elevation, yielding the significantly lowest values at the pine-oak forest. Elevation distribution patterns of prevalence for each genus were similar to those previously reported in other geographical areas (e.g., South America, Europe).

Relationship Between Genetic Variation and Diversity of Tree Species in Tropical Forests in the El Ocote Biosphere Reserve, Chiapas, Mexico

Knowledge of the genetic diversity of species in a biological community is useful for assessing the ecological and evolutionary processes that define the structure and dynamics of that community. We investigated the potential relationship between the trans-specific genetic diversity (or genetic diversity across tree species) and the diversity of tree species in a tropical subdeciduous forest. The nucleotide variation of the concatenated regions ITS 1 and ITS 3 (ITS1-3) was used to determine the trans-specific genetic diversity of 19 species of trees in five local communities at El Ocote Biosphere Reserve (REBISO), Chiapas, Mexico. Tree diversity was obtained by counting individual trees within 0.1 ha circular plots in each locality. The relationship between trans-specific genetic diversity and species diversity was established through simple linear regressions between genetic diversity parameters and community diversity. A correlation matrix was built with genetic distances (Kimura’s two-parameter model) and differences in species diversity between communities. A significant relationship was observed between nucleotide diversity (π) and species richness ( Sp), and a negative association between haplotype diversity and gamma diversity (γ). Our results show species-rich and genetically diverse tree communities and a weak association between trans-specific genetic variation and species diversity in tree communities at REBISO. This research suggests a possible ecological and genetic relationship within each community. Genetic diversity values may provide an important degree of variation upon which environmental selection pressures could operate, which may be helpful to face the current environmental modifications associated with climatic change.

Interspecific variation in tree- and stand-scale stemflow funneling ratios in a subtropical deciduous forest in eastern China

Stemflow is an important water flux in forested ecosystems, which is influenced by both biotic and abiotic factors. The stemflow funneling ratio, FP, is a straightforward parameter to express the funneling efficiency of individual trees,FP,Bt, or at the stand-scale, FP,Bs. Nevertheless, no known studies have compared the FP and its influencing factors between tree- and stand-scales in a subtropical deciduous forest. In this study, FP values from Q. acutissima and B. papyrifera trees were computed for a subtropical area of eastern China, and examined in relation to five biotic variables and ten abiotic variables. The relative contribution ratio (RCR) of each biotic and abiotic variable to FP,Bt and FP,Bs were evaluated by relative importance analysis. The median FP,Bs of B. papyrifera (104.2) was significantly higher than that of Q. acutissima (62.2), with the median FP,Bt of Q. acutissima and B. papyrifera both varying greatly among individual trees. Projected crown area (RCR = 29.2%) and diameter at breast height (RCR = 21.4%) were the two most important biotic factors governing FP,Bt of Q. acutissima, while the two critical biotic factors affecting FP,Bt of B. papyrifera were trunk lean (RCR = 62.2%) and tree height (RCR = 15.1%), respectively. At the stand scale, gross precipitation (GP), rainfall duration (DE) and vapor pressure deficit (D) were the three most critical factors affecting FP,Bs of Q. acutissima and B. papyrifera. GP and DE exerted positive effects but D a negative effect on stemflow generation. These findings provide new insights into the FP at both tree- and stand-scales within subtropical ecosystems.

Differential Use of Forest Patches by the Military Macaw Ara militaris (Psittacidae) in Coastal Tropical Forests of Jalisco, Mexico

Bahia de Banderas in Jalisco, Mexico, contains important vegetation areas for the maintenance and nesting of Military Macaws Ara militaris. However, the forests of the region are not used randomly by Military Macaws across the landscape. This study aimed to evaluate differences in floristic composition, diversity and structure among forest patches used by the macaws for nesting/ roosting or for feeding, and at sites from which the macaws are absent. Field sampling was conducted in 16 plots of 1,000m2 of tropical subdeciduous forest. Statistically significant differences were found in the floristic composition between patches used and avoided by Military Macaws. The used areas were approximately twice as diverse as the avoided areas. The forests at used sites presented a great abundance of species registered as part of their diet, in addition to non-food species such as Oxandra lanceolata, a tree that may be an important component of macaw habitat. In contrast, the dominant species in avoided areas are those associated with disturbed areas and do not provide food for Military Macaws. Our results indicate that Military Macaws select forest fragments in response to disturbance, using forest patches that offer suitable opportunities for nesting and feeding.—Flores-Lopez, E., Montero-Castro, J.C., Monterrubio-Rico, T.C., Ibarra-Manriquez, G., Lopez-Toledo, L. & Carlos Bonilla-Ruz, C. (2020). Differential use of forest patches by the Military Macaw Ara militaris (Psittacidae) in coastal tropical forests of Jalisco, Mexico. Ardeola, 67: 423-432.

Estructura y composición florística de la selva mediana subcaducifolia en Hobomó, Campeche, Campeche, México

Se estudió florísticamente la composición y estructura de la selva mediana subcaducifolia en dos sitios del área de Hobomó, Campeche, México. Se seleccionaron dos sitios, en cada uno se delimitaron 10 parcelas de 10 m2 × 10 m2 (1000 m2) y se midieron todos los individuos de ≥ 1 cm de diámetro. El análisis estructural de la selva mediana subcaducifolia se basó en los valores de importancia de las especies. La diversidad se estimó con el índice de Shannon-Wiener (H’). Mediante observaciones y recolectas se detectaron 79 especies de plantas vasculares, pertenecientes a 67 géneros y 30 familias. Las familias más diversas fueron Fabaceae y Rubiaceae en ambos sitios. El género más diverso fue Diospyros, seguido de Coccoloba y Guettarda. La diversidad de especies leñosas en los sitios 1 y 2 fue de 3.68 y 3.59, sus valores de equidad (uniformidad) de acuerdo con el índice de Pielou fueron de 0.88 y 0.87 y su densidad fue de 6610 individuos por hectárea (ind/ha) y 8670 ind/ha, respectivamente. Las tres especies con mayor densidad fueron Malpighia glabra, Guettarda combsii y Lonchocarpus xuul en el sitio 1 y Machaonia lindeniana, Coccoloba cozumelensis y Malpighia glabra en el sitio 2. Los valores más altos de los índices de valor de importancia fueron Bursera simaruba, Lonchocarpus xuul, Guettarda combsii, Platymiscium yucatanum y Malpighia glabra en el sitio 1 y Lysiloma latisiliquum, Bursera simaruba, Vitex gaumeri, Lonchocarpus xuul y Machaonia lindeniana en el sitio 2. Estas especies son las más importantes en la estructura y fisonomía de la comunidad vegetal. Se puede concluir que la riqueza de especies arbóreas de los dos sitios estudiados es similar (sitio 1con 63 spp. y sitio 2 con 62 spp.). La escasez o abundancia de las especies está relacionada con la actividad humana (extracción de madera), la cual afecta la estructura y composición florística.

Distribution and diversity of Papilionidae and Pieridae (Lepidoptera: Papilionoidea) in Loxicha Region, Oaxaca, Mexico

Introduction: A reliable list of species and the analysis of diversity patterns of hyperdiverse taxa, like butterflies, are fundamental for monitoring and managing biological resources. Oaxaca is one of the most diverse states in Mexico for many groups including Lepidoptera and most of its diversity is unknown. Objective: to estimate and describe the species richness and diversity of Papilionidae and Pieridae along an altitudinal gradient and five vegetation types in the Loxicha Region, Oaxaca, Sierra Madre del Sur. Methods: Sampling effort comprised 222 collecting days during a period of seven years. We estimated the alpha diversity for 17 sites within an elevational gradient from 80 to 2 850 m, with five vegetation types: tropical deciduous forest (TDF), tropical sub-deciduous forest (TSDF), cloud forest (low and middle levels) (CF), oak-pine and cloud forest (high level) (OPCF) and oak-pine forest (OPF). Results: We obtained a list of 69 species (27 Papilionidae and 42 Pieridae), of 34 genera and five subfamilies, from literature records and fieldwork. These species are 60 % of the Pieridae and 48 % of the Papilionidae recorded for the state. The Loxicha Region has 36 % of the Pieridae and 30 % of the Papilionidae of Mexico. Both families present different species richness patterns by vegetation type. Papilionidae is richer in the TDF with 23 estimated species and most of the species of this family (84 %) occur below 500 m. Meanwhile, species richness of Pieridae has non-significant differences among vegetations types, except for OPF which has fewer species than the other types. The elevational gradient was divided into three levels (0-750, 750-1 800, 1 800-2 850 m) showing a reduction of species richness and diversity for both families at higher altitudes. Conclusions: Papilionidae species are more restricted to a vegetation type or elevational level than Pieridae species. Likely reasons are higher vagility (including migrations) and wider ecological tolerance of most Pieridae.

Spatial-temporal variability of throughfall in a subtropical deciduous forest from the hilly regions of eastern China

Throughfall variability plays a crucial role in regulating hydrological and biogeochemical processes in forest ecosystems. However, throughfall variability and its potential influencing factors remain unclear in the subtropical deciduous forest because of its complex canopy and meteorological conditions. Here, the spatial variability and temporal stability of throughfall were investigated from October 2016 to December 2017 within a deciduous forest in the subtropical hilly regions of eastern China, and the effects of meteorological variables and distance from nearest tree trunk on throughfall variability were systematically evaluated. Throughfall variability during the leafed period was slightly higher than that during the leafless period inferred from the coefficient of variation of throughfall amounts (CVTF), with 13.2%–40.9% and 18.7%–31.9%, respectively. The multiple regression model analysis suggested that the controlling factors of throughfall variability were different in studied periods: Maximum 10-min rainfall intensity, wind speed and air temperature were the dominant influencing factors on throughfall variability during the leafed period, with the relative contribution ratio (RCR) of 25.9%, 18.7% and 8.9%, respectively. By contrast, throughfall variability was affected mainly by the mean rainfall intensity (RCR=40.8%) during the leafless period. The temporal stability plots and geostatistical analysis indicated that spatial patterns of throughfall were stable and similar among rainfall events. Our findings highlight the important role of various meteorological factors in throughfall variability and are expected to contribute to the accurate assessment of throughfall, soil water and runoff within the subtropical forests.

Are Mayan community forest reserves effective in fulfilling people's needs and preserving tree species?

Mayan community forest reserves (MCFR) play an important role in agricultural landscapes in Mexico, as they provide forest products and a broad variety of benefits that contribute to improving local people's livelihoods. Nevertheless, academia has generally considered conservation and use of forest resources to be incompatible. We describe the spatial configuration of MCFR, evaluate floristic and structural characteristics of woody vegetation present in selected reserves, and identify social norms that govern use and conservation of MCFR. These reserves largely consist of mature vegetation (80% of total cover); their plant structure is similar to that of the surrounding tropical sub-deciduous forest; and they house a large number of endemic species. The MCFR studied contain a total of 146 tree species and cover 11% of the study area, which includes at least 140 villages in the north-central part of the Yucatan Peninsula. These reserves are collectively managed and conserved by Mayan peasants in the interest of the common good. The communities in our study area combine conservation and use of forest resources, and we recommend that in public policy, government agencies and NGOs incorporate MCFR as a model of biological conservation and sustainable natural resource use, taking into account traditional knowledge and local norms that allow these reserves to function in a sustainable manner.

Surface pollen distribution from Akhnoor of Jammu District (Jammu and Kashmir), India: implications for the interpretation of fossil pollen records

The present study aims to document modern pollen assemblages and compare them with the extant vegetation, through palynological analysis of 40 modern moss cushions, from the Akhnoor sector of Jammu District (Jammu and Kashmir), India. The study revealed that the pollen of Pinus sp. (average 62%) dominates the pollen assemblages. The over-representation of Pinus pollen could be attributed to its high pollen productivity and excellent pollen dispersal capacity. However, other conifers (needle-leaved taxa) as well as broad-leaved taxa, with a few exceptions, are either sporadically recorded or remain palynologically silent (present in the extant vegetation but absent in the recovered pollen assemblages). This discrepancy could be owing to their long-distance transport by wind and/or water from the upland areas/the higher reaches of the Himalaya. Tubuliflorae, Cerealia and other cultural pollen taxa, and Poaceae, are well to poorly represented in the pollen assemblages. The associates of sub-tropical deciduous forests are poorly represented in the pollen spectra because they are not wind pollinated nor are they high pollen producers. The extant vegetation of the sampling location in Akhnoor of Jammu province plays a pivotal role in the present study, which has important implications for the interpretation of vegetation dynamics and associated climate change during the Holocene on the Indian subcontinent.

Variación en la abundancia de árboles maderables por efecto de borde en un bosque tropical subcaducifolio

Antecedentes: El efecto de borde afecta diferencialmente a las especies en sus estadios de desarrollo. El presente estudio analizó las condiciones ambientales asociadas a la abundancia por estadio de desarrollo de cuatro especies de árboles maderables en el borde de un bosque tropical subcaducifolio. Hipótesis: Los bordes presentan mayor incidencia lumínica y temperatura, condiciones favorables para las plántulas, por lo que se espera que en el borde se presente la mayor abundancia de plántulas con respecto al interior del bosque. Especies en estudio: Bursera simaruba (L.) Sarg. , Cedrela odorata L. , Guazuma ulmifolia Lam. , Lysiloma divaricatum (Jacq.) J.F. Macbr. Sitio de estudio y fechas: Reserva de la Biosfera “El Cielo” (Tamaulipas), México. Enero-diciembre 2016. Métodos: La abundancia por estadios de desarrollo y las condiciones ambientales fueron cuantificadas en el gradiente. Dichas variables se correlacionaron, además se contrastaron los requerimientos entre estadios y se asociaron con los ambientes identificados. Resultados: Guazuma ulmifolia mostró una respuesta negativa al efecto de borde, mientras que Cedrela odorata respondió positivamente. Los requerimientos ambientales difirieron entre los primeros estadios de desarrollo y los adultos. La abundancia de las plántulas se asoció a condiciones de mayor incidencia lumínica. Conclusiones: Los requerimientos ambientales afectan diferencialmente a cada estadio de desarrollo. La abundancia de plántulas se incrementa en condiciones de mayor incidencia lumínica, pero no en el resto de los estadios, excepto en C. odorata . La pérdida de cobertura y la consecuente formación de bordes pueden llevar a una reducción en la abundancia de estas especies, con implicaciones económicas.