Tropical Thorn Forest Research Articles

Assessment of Annual Litterfall of Woody Plant Community in Southern Thorn Forest, Tirunelveli, Peninsular India

The biological phenomenon, litterfall acts as a connection between tree canopy and substratum of the habitats, influencing the concentration of vital soil nutrients thereby contributing to the tree growth and forest productivity. Information on litter generation of tropical forests including tropical thorn forest is lacking. Therefore, the current study was conducted to find annual litterfall of tree community existing within a Reserve Forest in Tirunelveli, India. A field ecological study was carried out to find annual litter production of woody plant community. Litter traps were kept randomly across the forest to assess the litter production. The litter fallen in each trap was collected separately on monthly basis for one calendar year. The collected litter was separated in to four different classes viz., leaf, wood, amorphous and reproductive organs. The relationship of climatic variables with litterfall was estimated by Pearson’s simple correlation test. The annual litter generation of the study area was estimated at 8.058 tons ha-1 y-1. The amount of total fallen and four classes litter per month varied significantly. In addition, litterfall did not show any significant relationship with the mean monthly temperature (p = 0.128; r2= 0.216) and monthly rainfall (p = 0.817; r2 = 0.0056). The deciduous species accounted for 95% (3.449 tons ha-1) of total annual leaf litterfall. Among four litter classes, the leaf litter accounted for 45.05%. The quantity of annual litterfall recorded from present study area is comparable with other tropical dry forests. The present study concentrated on limited forest areas, further studies with larger study area are needed to quantify the actual annual litter generation of southern thorn forests flourishing in various districts of Tamil Nadu.

Quantifying soil erosion and soil organic carbon conservation services in indian forests: A RUSLE-SDR and GIS-based assessment

Indian forests, having sixteen types of vegetation, provide various ecosystem services. Forests reduce water erosion of soil, reduce floods and conserve low river flow during dry seasons. Present study estimated annual sedimentation, texture, soil organic carbon control service of forests of India using the Revised Universal Soil Loss Equation (RUSLE) and Sediment Delivery Ratio (SDR) approach through GIS technique along with identifying important drivers responsible for erosion in forests. The soil erosion control service was based on five factors viz., rainfall erosivity, soil erodibility, slope, crop management, conservation practice factor and SDR across the various forest dominated river basins. Geo-detector modelling was performed to evaluate environmental drivers responsible for soil erosion. Valuation of soil control service of the India’s forests was estimated based on damage and replacement cost method. Annual soil loss rate was maximum in Tropical Thorn Forest and in Ganga River basin. Maximum sediment control and SOC conservation against the soil erosion control service by India’ forests were due to Tropical Dry Deciduous Forest with a total annual sedimentation control and SOC conservation of 33,056,560 tonnes and 3,31,115.06 tonnes, respectively. The conservative estimate of the economic value of soil conservation service by the forests of India was US$ 535.6 M with an average of 4.40 US$ ha−1 and a maximum share of value for Tropical Dry Deciduous Forest i.e. 294.18 million US$ and average maximum value for Littoral and Swamp Forest (28.91 US$ ha−1). The soil erosion in Tropical and Sub-tropical Forest was influenced by the interactive effects between NDVI and Bulk Density. In contrast, soil erosion in the temperate and alpine area was influenced by anthropogenic activity in combination with climatic factors. Present study accounts the role of India’s forests for the soil conservation service and may provide inputs to implement forest and reservoir management strategies besides providing information for Integrated Watershed management and Catchment Treatment Plans.

Breeding and Nesting Behaviour of Red-Vented Bulbul (Pycnonotus cafer) in Shaheed Benazirabad District (Tropical Thorn Forest) Sindh Province of Pakistan

Breeding and Nesting Behaviour of Red-Vented Bulbul (Pycnonotus cafer) in Shaheed Benazirabad District (Tropical Thorn Forest) Sindh Province of Pakistan

Effect of invasive plant, Prosopis juliflora on tree diversity in the southern tropical thorn forest of Western Ghats, India

ABSTRACT The spread of invasive alien species (IAS) affects the conservation of tropical forest ecosystems. This study assessed the effect of Prosopis juliflora, an invasive species, on the tree diversity in the southern tropical thorn forest of Chinnar Wildlife Sanctuary (CWS), a protected area in the southern Western Ghats, Kerala, India. The results showed a significant difference in the diversity of mature tree species between invaded and uninvaded areas. The P. juliflora invaded area has less tree diversity than P. juliflora non-invaded area only in the mature tree phase. Examining the relationship between the abundance of P. juliflora and tree diversity (r = -0.59), the study revealed a negative relationship between the biotic components. There is a need to eradicate P. juliflora from CWS for the conservation of biodiversity.

Allometric Aboveground Biomass Models for Northern Delhi Ridge Forest

Bio energy obtained through forest biomass is a promising renewable energy option that provides a more environmentally sustainable alternative to fossil resources by reducing the net flux of greenhouse gases to the atmosphere. India, a developing nation is also in the process of building forest biomass models to study the potential of forests in short and long - term carbon mitigation. Earlier, traditional and destructive sampling were the popular methods for the aforesaid purpose. Recently, non - destructive methods have been adopted applying different allometric equations mostly developed outside India. Thus, there was a need to develop non- destructive allometric aboveground (AGB) models complementing the Indian climate. Also, there was a scarcity of domestic/local AGB models for arid, semi- arid, northern tropical thorn forest of India. The objectives of this study were to develop site-specific and mixed- species allometric models to predict AGB, at the Northern Delhi Ridge Forest (NDRF) using nonlinear mathematical functions. The model has a wide scope and can be applied to adjoining areas as well having similar climatic conditions. Three allometric combinations were tried to fit the aboveground biomass data obtained from the ridge forest. A three- parametric Richard’s model (with predictor variable x=D2H) was best fitted to AGB (R2adj= 0.9463) values for larger trees. Meanwhile, for juvenile plants, a three- parametric Richard function was best fitted (R2adj= 0.9733) when (x = DH) was used as a predictor variable. Cross- validation of model parameters exhibited statistical stability.

Conserving the threatened woody vegetation on dune slopes: Monitoring the decline and designing adaptive strategies for restoration

The southern tip of the Thal desert in Pakistan harbors the remnants of the original tropical thorn forest, amounting to two percent, which covered the province of Punjab a hundred years ago. In the past three decades, there has been a progressive decline in woody species cover on dunes, which is directly related to the increase in population in the surrounding area. Stabilized and destabilized dunes were subjectively selected followed by quantification of cover and diversity of woody species on the top and lower slopes. Dunes closely resembling the overall cover were grouped to suggest corresponding restoration measures. The results suggest that trends of decrease in cover and diversity of woody species were evident in the upper slopes of some stabilized dunes having less than 50% cover. The destabilized dunes with less than 20% cover are highly vulnerable to erosion. A general trend observed among dunes was that with a decrease in the cover of upper slopes, there is a decrease in the cover on lower slopes. The number of destabilized dunes is increasing without effective restoration measures against the prevailing trends of disturbances. Ranking dunes on the basis of cover could help in proposing simple restoration measures as a first step towards developing an understanding of designing adaptive strategies to restore the woody cover.

Relative Humidity, Soil Phosphorus, and Stand Structure Diversity Determine Aboveground Biomass along the Elevation Gradient in Various Forest Ecosystems of Pakistan

The direct effects of relative humidity and soil on aboveground biomass (AGB) versus the indirect effects mediated by stand structural diversity remain unclear in forest ecosystems across large-scale elevation gradients. Forest inventory data containing 15,260 individual trees and 104 tree species from 200 forest plots were collected. The result shows that the relative humidity, elevation, and Coefficient of Variation of Diameter at breast height (CVD) significantly influence AGB in the Tropical Thorn Forest (TTF). Regarding elevation, CVD was positive and significant, and relative humidity and SR negatively impacted AGB in sub-tropical broad-leaved forests (STBLF). In moist temperate mixed forests (MTMF), soil phosphorus and CVD have a significant positive impact, while relative humidity, elevation, and SR negatively influence AGB. Elevation and CVD have positive, while SR and soil phosphorus have a negative and insignificant effect on AGB in Dry Temperate Conifer Forests (DTCF). Soil phosphorus and relative humidity positively affected AGB (β = 0.021), while elevation, CVD, and SR negatively affect AGB in dry temperate, pure pine forests (DTPPF). Relative humidity and soil phosphorus have a positive direct effect on AGB in multi-species forests. The current study suggests that AGB primarily depends on relative humidity, soil phosphorus, and elevation in different forest types.

Floristic Diversity and Conservation Status of Non-Reserve Forest Area of Kachchh District, Gujarat

Kachchh, the largest district of western Indian in Gujarat state that depicts thorn scrub forest, grassland, marine and mangrove ecosystem. The study aimed at documenting the floral diversity of the Khambhla forest, located between 23°23'42.0"N 69°14'14.5"E to 23°26'11.9"N 69°15'07.0"E in the western block of Nakhatrana in Kachchh. This particular forest has an undulating terrain with small hillocks, classified under tropical thorn forest. In the present study, a total of 107 species belonging to 86 genera from 31 families are recorded. Prosopis juliflora (Sw.) DC., an invasive species that has taken over the native vegetation of Kachchh and has altered the community structure of an ecosystem. A participatory approach of the present study revealed that the land expansion of P. juliflora, composition of nutritive grasses used for pastoralism has changed. Dense invasion causes migration of the wildlife. The study concludes with recommendations for effective management of P. juliflora to restore the native biodiversity of Kachchh.

Spatio-temporal variability of water use efficiency and its drivers in major forest formations in India

Forests play a significant role in mitigating the effects of climate change and regulating the biogeochemical cycles. Water use efficiency (WUE) is an important indicator that links the carbon and water cycles in terrestrial ecosystems. In the present study, WUE of major forest formations of India was calculated from 2003 to 2018 as the ratio of Moderate Resolution Spectroradiometer (MODIS) Gross Primary Productivity (GPP, MOD17A2H) to evapotranspiration (ET, MOD16A) using the Google Earth Engine platform. The spatial distribution of WUE was mapped and the inter-annual and monthly variations were analysed. The mean annual WUE of forests ranged from 1.78–2.02 gC kgH2O−1. It was observed that tropical thorn forests had the highest WUE (3.52 ± 1.08 gC kgH2O−1) and moist alpine scrub had the lowest WUE (1.05 ± 0.17gC kgH2O−1) among the forest type groups of India. WUE of forests showed an increasing trend with latitude and decreasing trend with elevation. To understand the influence of various bio-meteorological drivers on WUE and their importance in governing these influences, Random Forest (RF) algorithm was used. The bio-meteorological drivers were able to explain 65% of the variability in WUE. Temperature was identified as the most important driver in influencing the WUE of forests. Based on the findings of the study, it can be expected that the global increase in temperature would negatively affect the WUE of the major forest formations of India.

Density, diversity and community composition of trees in tropical thorn forest, peninsular India

Tropical thorn forests (TTFs) are characterized by the presence of small and thorny trees which usually shed their leaves in dry season. A quantitative phytosociological study was conducted in Uthumalai Reserve Forest of Peninsular India to record density, species richness, diversity and population structure of trees. Diameter of all free standing trees ≥1 cm diameter at breast height (DBH, cm) was measured at 1.37 m above the ground. A sum of 4135 trees ≥1cm DBH recorded from one hectare study plot. With 2272 (54.94%) individuals Dalbergia spinosa dominated the study plot followed by Commiphora berryi (484, 11.70%), Grewia flavescens (259, 6.26%), Dichrostachys cinerea (206, 4.98%) and Anogeissus pendula (171, 4.14%). In total, 26 species belonged to 19 genera and 15 families found in one ha study plot. The family Mimosaceae had a large number of species followed by Apocynaceae, Capparidaceae, Tiliaceae, Rhamnaceae. Rubiaceae (each 2 species). Stand basal area of tree community recorded as 15.238 m2 ha-1. Commiphora berryi constituted 50.80% (7.74 m2 ha-1) of stand basal area followed by Dalbergia spinosa (19.43%, 2.96 m2 ha-1). The forest showed a reverse J shaped population structure. Shannon diversity (H), equitability (H’) and Simpson’s dominance (D) indices of study area recorded as 1.76, 0.54 and 0.335, respectively. Dalbergia spinosa, Commiphora berryi, Grewia flavescens, Dichrostachys cinerea and Anogeissus pendula topped the species important value index with 87.80, 73.53, 20, 19.79, 17.43 scores, respectively. In family important value index, Papilionaceae topped the list followed by Burseraceae and Mimosaceae with scores 129.32, 74.23 and 34.43, respectively. The study area endowed with a moderate species richness and diversity, and acts as one of the homes for an IUCN’s vulnerable tree species.

Vegetation of Kalyana Karnataka Region, India

Understanding the diversity of vegetation is a useful tool in plant ecology and forestry to compare the composition of different species. Kalyana Karnataka region is one of the largest arid regions in India. The natural vegetation can be seen mostly in the valleys and hill locks only. The forest vegetation generally falls under Southern tropical dry deciduous forest and Southern tropical thorn forests. Dry deciduous forests are found in small blocks almost throughout the area but the mere composition is at Chincholi in Kaluburagi district, Khanapur and Changler in Bidar District and Sandur and Sogi in Bellary. Trees of this region are generally drought resistant with wide distribution and have great adaptability (Anogeissus latifolia, Soymida febrifuga etc.). The occurrence of teak (Tectona grandis) in low to fair amount characterizes this type. Yadgir, Raichur and Koppal district comprising predominant thorny and hardwood species, main components are Acacia chundra, A. leucophloea, Albizia amara, Ixora arborea, Cassis fistula etc.; this can be classified as thorn forests. Associated and encountered shrubs and herbs in the region were also recorded. Interestingly, few insectivorous plants viz., Drosera indica, D. Burmanii, Utricularia species are found. Pteridophytes like Isoetes coramandaliana, Selaginella bryopteris, Pteris jeranifolia, Adiantum incisum etc. are creating botanical interest about the forest vegetation of Yadgiri and Raichur district.

Estimation of soil carbon pools in the forests of Khyber Pakhtunkhwa Province, Pakistan

Forest soils have high carbon densities compared to other land-uses. Soil carbon sequestration is important to reduce CO2 concentrations in the atmosphere. An effective climate change mitigation strategy involves limiting the emissions of greenhouse gases from soils. Khyber Pakhtunkhwa is the most forested province of Pakistan, hosting about one-third of the country’s 4.5 × 106 ha forest area. Soil organic carbon in the province’s forests was estimated through a field-based study carried out during 2014–17 covering the whole province. Data was collected from 373 sample plots laid out in different forest types using a stratified cluster sampling technique. The total quantity of soil organic carbon was estimated at 59.4 × 106 t with an average of 52.4 ± 5.3 t/ha. About 69% of the total soil carbon is present in temperate forests. Subtropical broad-leaved and subtropical pine forests constitute 11.4% and 8.8% of the soil carbon stock respectively. Similarly, subalpine and oak forests have respective shares of 5.1% and 5.7% in the soil carbon pool. The lowest carbon stock (0.1%) was found in dry-tropical thorn forests. The highest soil carbon density was found in subalpine forests (69.5 ± 7.2 t/ha) followed by moist temperate forests (68.5 ± 6.7 t/ha) and dry temperate forests (60.7 ± 6.5 t/ha). Oak forests have carbon density of 43.4 ± 7.1 t/ha. Subtropical pine, subtropical broad-leaved and dry tropical thorn forests have soil carbon densities of 36.3 ± 3.7, 32.8 ± 6.2 and 31.5 ± 3.5 t/ha, respectively. The forests of the Khyber Pakhtunkhwa province have substantial amounts of soil carbon which must be conserved for climate change mitigation and maintenance of sound forest health.

Anthropogenic impact on the distribution of the birds in the tropical thorn forest, Punjab, Pakistan

The present research was conducted to assess the anthropogenic impacts on avian diversity around the river Chenab, Pakistan. The avian diversity was recorded on different landscapes along the river Chenab, that is, forest, agricultural, rural, and urban habitats. The data on diversity and distribution of various avian species were collected through linear count along with direct count methods viz. personal observations and sound records and indirect count methods viz. presences of carcasses and meeting with local communities. The habitat preferences of birds varied significantly. A decline in avian diversity was observed from forest habitat to urban landscapes. One year of bird surveys compiled a total of 150 species from all habitats along the river Chenab. Computed statistical data show that Shannon's index provides a quantitative report of diversity which was highest at forest habitat (4.261) followed by rural forest habitat (3.746), agri–rural habitat (3.746), agriculture habitat (3.623), WLH (2.723), urban vegetative habitat (3.215), and very least at urban nonvegetative habitat (2.247). It can be concluded from the present study that many of the avian species have specific habitats and also noted that corridors and connections among different landscapes are important for the conservation of avian diversity.

A new fossil wood from the highly diverse early Eocene equatorial forest of Gujarat (western India)

During the early Eocene (∼55–52Ma), when the Indian subcontinent relished equatorial climatic conditions, lignite was deposited along its north western margin. Lignite mines of northwestern India have proved to be an outstanding resource for palaeoenvironmental information. The Vastan lignite mine of the early Eocene age situated near Surat district (Gujarat) is one of the well-dated and fossiliferous lignite mines in western India. A fossil wood, retrieved from this mine, is systematically described and shows a strong resemblance to the modern genus Chisocheton of the family Meliaceae. Plant fossils are the best source to reconstruct the palaeoenvironment of any region, and here a luxurious, highly diverse tropical evergreen forest is interpreted in and around the fossil locality in contrast to the tropical thorn forest of the present day. This early Eocene highly diverse equatorial forest, once covered a significant portion of the Indian subcontinent, is now restricted in fringes known as Western Ghats in south India attesting to changes in climate.

Multivariate Analysis Of Vegetation In Wet Temperate Forests Of Pakistan

The present investigation focuses on the floristic composition in wet temperate forests of Pakistan. This area was selected as it has variation and diversity i.e. downward the tropical thorn forests and upward the alpine meadows. Wet temperate forest has high diversity of vulnerable plant species. It is situated in the Galiat Forest plants division of Abbottabad between 34◦-1' to 34◦-3.8' N latitude and 73◦-2222.8' to 73◦-27.1' E longitude over an area of about 1684 hectares. Five hierarchy levels of classification of 27 sites were analyzed by (DCA). Four plant associations were recognized on the basis of cluster analysis. Deterended Correspondence Analysis (DCA) and Correlation Coefficient to detect the relationship between altitude and some environmental factors with the composition and structure of plants communities. The major families were Rosaceae, Pteridaceae, Pinaceae, Lamiaceae and Asteraceae. I. Introduction Pakistan is a sub-tropical country which is situated between 20 and 37° N latitude 75° E longitude. Ayubia national park lies in the Himalayan wet temperate forest. Ayubia National Park is a protected area of 3,312 hectors (8,184 acres) located in Abbottabad District, Khyber Pakhtunkhaw province, northern Pakistan. It was declared a national park in 1984. The area supports temperate forest and temperate and broad mixed forest eco-region habitats, with an average elevation of 8,000 feet (2,400 m) above the sea level. Ayubia National Park is surrounded by seven major villages and four small towns of Thandiani, Nathiagali, Ayubia and Khanspur. Here precipitation may sometimes exceed 600mm, the making of these montane forests a sort of enclave in which the plants and diversity of natural sites make it a sort of bio-geographical crossroad between the sub- montane and alpine meadow vegetation (1). For the temperate species the knowledge of habitat association is limited (2). These forests are most attractive in the Himalayas with varying degree of coniferous species including Abies pindrew, Pinus wallichiana, Taxus wallichiana, and Cedrus deodara with varying admixture of evergreen and deciduous patches of broad leaved forests. After the snow melts, a variety of ferns being the first to develop in the spring season, followed by a variety of perennial species. There is also a good deal of mosses and lichen on the tree trunks (1). The impact of snow pressure and strong winds on vegetation structure and species composition in expected at high altitude (3-10). Chemistry of soil is influenced by the vegetation while the composition, physiognomy, productivity and its communities is influenced by soils (11). The vegetation of the study area is dominated by conifers species, principally pine and fir with scattered individuals broad leaves trees, i.e.; oak (12). The primary objective of this study is to explore the factors that determine the boundaries and composition of plant communities on the wet temperate forest of Ayubia National Park.

Hierarchical Approach for Developing Baseline Soil Organic Carbon Database and Its Distribution in India

This study involves generation and logical integration of non-spatial and spatial data in a geographical information system framework to address the gap in national level soil organic carbon estimates. Remote sensing derived inputs and other spatial layers are corrected and integrated using same geographical standards. A relational data base of soil organic carbon density of Indian forest was prepared with attribute information. Hierarchical approach was followed to stratify and verify each sample from the data base using the corrected input layers in GIS and the resulting spatially distributed data is called Indian forest soil organic carbon database. The estimated mean soil organic carbon density for Indian forest is 70 t ha−1 and varied from 35.4 t ha−1 in Tropical thorn forest to 104.2 t ha−1 in Himalayan moist temperate forest in the upper 30 cm of soil depth. Due to large variations in the surface layers the estimated standard error ranged from ±1.5 to 15 % for the upper 30 cm layer which is generally higher than the bottom soil layers. The level of detail in the data base helps to establish base line information for global, national and regional level studies.

Natural protected areas of San Luis Potosí, Mexico: ecological representativeness, risks, and conservation implications across scales

Assessments of the conservation status of natural resources have been conducted at large (i.e., global, continental, and countrywide) extents. Studies at finer scales, however, can yield increased detail needed to identify conservation strategies for smaller scales which can contribute to goals at the larger extents. Our study was conducted at the scale of a single state, San Luis Potosí, in Central Mexico. Although the state harbors great biological diversity, large areas covered by natural vegetation communities have been and continue to be destroyed by land use changes, cattle grazing, and mine-generated pollution. Our purposes were to quantify the proportion of distribution within natural protected areas (NPAs) of land cover classes, soil types, ecoregions, and altitudinal steps. In addition, within individual NPAs, we aimed at assessing risks. We conducted our analysis at the 1:1, 1:250,000, and 1:1,000,000 scales depending on layer availability. Our results show that actions within the state could contribute to federal and global conservation goals by protecting sites of globally imperiled ecosystems (cloud forests and natural grasslands). At a finer scale, we identified that piedmont scrubland, medium and low tropical moist forests, wetlands, and low elevation habitats are rare and/or constitute conservation omissions within the state. Similarly, ecoregions with mesquite, semi-deciduous, and moist tropical thorn forest, wetlands, and low elevations (<1200 m.a.s.l.) are conservation omissions or gaps. Finally, at the smallest scale, risks within some protected areas (PAs) include the presence of agriculture, cattle grazing, and mine tailings from mines dedicated to extraction of Au, Ag, Cu, Pb, and Zn. Therefore, management within these PAs should minimize such risks through identification of the most important conservation zones within the PAs, and implementation of local legislation prohibiting such activities at the immediacies of conservation zones. Approaches like ours within similar administrative units will help identify ecosystems that are vulnerable and not well protected. However, to prioritize conservation action it is also important to consider surrogates such as species from different groups and ecosystems, as well as rarity and complementarity of such surrogates.

Estudo da variabilidade anual e intra-anual da precipitação na região Nordeste do Brasil

Este trabalho analisou as séries temporais de precipitação e do número de dias de chuva na região Nordeste do Brasil com o propósito de identificar as áreas mais susceptíveis às estiagens mais prolongadas. Os dados utilizados neste estudo foram obtidos da Agência Nacional de Águas (ANA) e da Superintendência do Desenvolvimento do Nordeste (SUDENE), para o período de 1935 a 2000. Foram construídos mapas do coeficiente de variação e do número de dias chuvosos para os períodos anual, seco e chuvoso. Os resultados deste trabalho permitiram concluir que os valores dos coeficientes de variação da precipitação e do número de dias chuvosos no semiárido são maiores do que no litoral, agreste e noroeste da região Nordeste do Brasil. Os maiores valores de coeficiente de variação são associados aos menores valores de precipitação e do número de dias chuvosos. A variabilidade da precipitação é maior no período seco do que no período chuvoso. A alta variabilidade da precipitação e do número de dias de chuva são fatores limitantes na agricultura de sequeiro nas microrregiões localizadas nas áreas semiáridas do Nordeste do Brasil.

Persistent changes in NDVI between 1982 and 2003 over India using AVHRR GIMMS (Global Inventory Modeling and Mapping Studies) data

The preliminary results of Normalized Difference Vegetation Index (NDVI) change studies over India using data from Advanced Very High Resolution Radiometer Global Inventory Modeling and Mapping Studies (AVHRR GIMMS) between 1982 and 2003 are presented. The three methodologies of univariate differencing, temporal profiling and anomaly analysis were undertaken. Univariate differencing was used to determine overall NDVI change between 1982 and 2003. A persistence filter was used to filter out ephemeral changes. The temporal profile analyses were carried out over different meteorological subdivisions to compare changes in NDVI with rainfall patterns. In the anomaly analysis, the areas of change were analysed over different land cover categories derived from IRS‐WiFS data. The preliminary results indicate that positive trends in vegetation change occurred over most parts of the country and these changes appear not to be highly correlated with rainfall data, indicating that land cover transformations may be the major driving force behind the changes. The land cover classifications experiencing the greatest increasing NDVI were tropical thorn forests and intensive agriculture and the land cover experiencing very slow growth included current jhum, tropical moist deciduous and temperate evergreen forest. Five‐year moving averages indicate a general increase in NDVI from 1986 to 1998 and then declining thereafter. This is a concern in most of the meteorological subdivisions.

Taxonomy, Distribution, and Natural History of the Genus Heteromys (Rodentia: Heteromyidae) in Western Venezuela, with the Description of a Dwarf Species from the Península de Paraguaná

Heteromys anomalus is widely distributed along the Caribbean coast of South America and was generally considered the only spiny pocket mouse present in Venezuela until H. australis was reported recently from the Cordillera de Mérida. Here, I revise the spiny pocket mice of western Venezuela and compare specimens from the semi-insular Península de Paraguaná with samples from throughout the distributional area of H. anomalus. Morphological comparisons with all other species of the genus suggest that the Heteromys from Paraguaná are closely related to H. anomalus, but univariate and multivariate analyses show that they are much smaller than samples of H. anomalus. In addition, adults from Paraguaná display differences in cranial shape when compared with adults of H. anomalus. Hence, specimens from Paraguaná are here described as a new species, Heteromys oasicus, and taxonomic treatments of H. anomalus and H. australis in western Venezuela are also provided. Although the original geographic context of this case of dwarfism in body size is unknown, H. oasicus currently appears to be isolated in mesic vegetation on the low Cerro Santa Ana and Fila de Monte Cano, which lie in a matrix of tropical thorn forest. The new species represents one of the few vertebrates considered endemic to Paraguaná, but basic inventories and taxonomic studies are not yet complete in the region.