Species-habitat associations in a Sri Lankan dipterocarp forest

Forest structure and species distribution patterns were examined among eight topographically defined habitats for the 205 species with stems ≥ 1 cm dbh inhabiting a 25-ha plot in the Sinharaja rain forest, Sri Lanka. The habitats were steep spurs, less-steep spurs, steep gullies and less-steep gullies, all at either lower or upper elevations. Mean stem density was significantly greater on the upper spurs than in the lower, less-steep gullies. Stem density was also higher on spurs than in gullies within each elevation category and in each upper-elevation habitat than in its corresponding lower-elevation habitat. Basal area varied less among habitats, but followed similar trends to stem density. Species richness and Fisher\u27s alpha were lower in the upper-elevation habitats than in the lower-elevation habitats. These differences appeared to be related to the abundances of the dominant species. Of the 125 species subjected to torus-translation tests, 99 species (abundant and less abundant and those in different strata) showed at least one positive or negative association to one or more of the habitats. Species associations were relatively more frequent with the lower-elevation gullies. These and the previous findings on seedling ecophysiology, morphology and anatomy of some of the habitat specialists suggest that edaphic and hydrological variation related to topography, accompanied by canopy disturbances of varying intensity, type and extent along the catenal landscape, plays a major role in habitat partitioning in this forest. Copyright © 2006 Cambridge University Press

COMPARISON OF FLORISTIC DIVERSITY OF FOUR WOODLAND TYPES IN THE UPPER HANTANA CAMPUS LAND

In the Upper Hantana campus land, three broad-leaf woodlands Peresereanthes fa/cataria.A /stonia macrophylla, or mixed species woodland and Pinus caribaea woodland grow inproximity to one another. The wide range of floristic diversity exhibited by these differentwoodlands was compared using plot sampling.The overstorey vegetation of the Alstonia woodland showed the highest, i) density, ii)floristic richness, iii) proportion of endemics and iv) plant diversity, foIlowed in decreasingorder by that in the Peresereanthes-, mixed-, and Pinus woodland. In the understoreyvegetation, floristic diversity «10 ern) was highest in Peresereanthes woodland, foIlowedin decreasing order by that in Alstonia-, mixed species-, and Pinus woodlands. Speciesrank abundance plots of overstorey and understorey species show that over storeyvegetation in Pinus woodland, fits the geometric series, whereas the others fit the logseries or log normal model.The broad-leaf species woodlands in Upper Hantana also showed better naturalregeneration of an array of species. AIl woodlands showed differences in micro-siteconditions. Levels of human disturbance and burning may contribute to differencesamongst them. These results provide baseline ecological information on naturalregeneration in different woodland types and indicate their relative potential forconservation of biodiversity and water resources.

FRUTING PHENOLOGY OF EIGHT Shorea SPECIES IN SINHARAJA MAN AND BIOSPHERE RESERVE

The canopy of Sinharaja rain forest is dominated by Mesua and Shorea spp., which areendemic to Sri Lanka. Information on the fruiting phenology of Shorea is vital, in termsof identifying trees as mother trees and collecting seeds for restoration and reforestationof degraded forest areas in the south-western part of Sri LankaThe phenology of eight Shorea species, [SO affinis, S. congestiflora, S. trapezifolia and S.zeyJanica belonging to the Thiniya group and S. cordifolia, S. megistophyJ/a, S.worthingtonii and S. disticha belonging to the Beraliya group] were examined foreighteen years. Fruiting of selected individuals was recorded fort-nightly as a percentageof the observable part of the crown in flower. The effect of environmental parameters onfruiting was assessed using Spearman rank correlation coefficient.In all species, the number of trees participating in a given fruiting event differed greatlybetween years. Individuals of S. trapezifolia and S. zeyJanica had more intense fruitingactivity (>50%) in most years while, it was only 1-50% in S. congestiflora. Fruitingintensities of individuals of the Beraliya group varied relatively little among differentfruiting episodes. An annual fruiting pattern among the Thiniyas and a supra-annualpattern in the Beraliyas were observed. The number of flowering episodes per tree washigh in members of the Thiniya group. Fruit fall was tightly synchronized among theBeraliyas, but sequential among the Thiniyas.The monthly rainfall and the fruiting intensities of all Shorea species, except in S.cordifolia and S. zeyJanica, were significant. The seasonal rainfall and fruitingintensities of four Shorea species were significantly correlated. The timing and intensityof fruitingwas observed to coincide with favorable environmental conditions.This project was funded by grants from by the USAID (Grant No: DPE-5542-G-55-4073-00) through Harvard University, U. S. A. and the John D. and Catherine T.MacArthur Foundation and the Britin Scholarship Fund

Kandyan home gardens: Faunal repositories in Sri Lanka.

Kandyan home gardens are one of the major designs of sustainable land use systems that have evolved over hundreds of years incorporating high biodiversity and providing a diverse and stable supply of socio-economic products and service benefits to householders in Sri Lanka. A study was carried out in three home gardens in the Kandy district from May to December 2009 with the objectives of (a) identifying spatial distribution of terrestrial vertebrates in different vegetation strata, (b) their diurnal and seasonal variations, (c) plant-animal interactions, (d) nesting habits and (e) diet composition. A total of 93 terrestrial vertebrate species including seven amphibians, 23 mammals, 43 birds, and 20 reptiles were recorded. These comprised 14 endemic species, 71 native, four introduced mammals and two migrant birds. Terrestrial vertebrate assemblages were similar in Home garden 1 and 3. According to the fully-nested ANOVA, statistically significant differences were found in the composition of terrestrial vertebrates and the home gardens (P=0.005<0.05), and their vegetation strata (P=0.005<0.05). However, no statistically significant differences were observed between richness of terrestrial vertebrates and the monsoonal periods (P=0.966>0.05), as well as the time of the day (P=0.775>0.05). A positive relationship was obtained between canopy cover and number of bird nests in all home gardens (rs = +1, α = 0.05).Commensalism was the most frequently recorded relationship in all three home gardens. Overall, the diversity of animals and their interactions were different in the three Kandyan Home Gardens studied. Preventing the degradation of home gardens can be considered as a means of conserving biodiversity. There is scope to develop the Kandyan Home Garden system as an important strategy to conserve biodiversity outside the natural and protected area systems

Use of Gliricidia sepium as a Nurse Plant to Reforest Man-made Grasslands in the Knuckles Forest Reserve, Sri Lanka

Biodiversity richness and socially beneficial watershed services are high in the KnucklesForest Reserve. However, the lower montane forest patches on the eastern slopes of the KFRare highly fragmented mainly due to anthropogenic disturbances. If these forest fragments arenot connected in the near future, they will disappear from the landscape due to their lowregeneration rates. Native tree species when used for restoration of these lands faces manydifficulties due to various biotic and abiotic stresses including harsh microclimatic conditionsand infertile soils. Therefore, usage of a nurse plant will facilitate the growth of target speciesdue to creation of favourable microclimatic conditions. Gliricidia sepium has been used as ashade plant in Sri Lanka, since colonial times. More recently it has been used for indigenousfarming practices, soil stabilization, living fences and as fuel wood, animal forage, greenmanure. In our research we investigate the potential of G. sepium as a nurse plant to establishfour native tree species on man-made grasslands in central Sri Lanka. The study wasconducted on four blocks of grasslands. Four replicates of each of the three island sizes(small 4 m2, medium 16 m2, and large 64 m2) were created inside each block. One set ofislands in each block were planted with G. sepium stakes at 2 m intervals in a grid format.The other set of islands in each block was kept as a control without planting G. sepiumstakes. Seedlings of Macaranga indica, Bhesa ceylanica, Symplocos cochinchinensis andEugenia bracteata were planted randomly in islands with and without G. sepium stakes.After three months of establishment, the survival rate of G. sepium in the four blocks wasmore than 80% and the survival rate of the G. sepium was 20% higher in the small andmedium islands than the large islands. The mean number of sprouts per stake was more thaneight in medium and large islands and less than six in small islands. The mean survival ratewas higher (5.8%) and the mean growth rates was lower (0.006%) for all the four nativespecies with G. sepium than without G. sepium after three months of planting. G. sepiumincreased the survival rates of native species after three months of establishment due tofavourable microclimatic conditions created by them. However, growth rate of the nativespecies which were planted with G. sepium was lower probably due to interspecificcompetition. Therefore, G. sepium can be used as an effective nurse plant in initial phases ofreforestation programmes to increase the survival rates of native tree species on degradedsubmontane sites in Sri Lanka.

Phylogenetic turnover along local environmental gradients in tropical forest communities

© 2016, Springer-Verlag Berlin Heidelberg. While the importance of local-scale habitat niches in shaping tree species turnover along environmental gradients in tropical forests is well appreciated, relatively little is known about the influence of phylogenetic signal in species’ habitat niches in shaping local community structure. We used detailed maps of the soil resource and topographic variation within eight 24–50 ha tropical forest plots combined with species phylogenies created from the APG III phylogeny to examine how phylogenetic beta diversity (indicating the degree of phylogenetic similarity of two communities) was related to environmental gradients within tropical tree communities. Using distance-based redundancy analysis we found that phylogenetic beta diversity, expressed as either nearest neighbor distance or mean pairwise distance, was significantly related to both soil and topographic variation in all study sites. In general, more phylogenetic beta diversity within a forest plot was explained by environmental variables this was expressed as nearest neighbor distance versus mean pairwise distance (3.0–10.3 % and 0.4–8.8 % of variation explained among plots, respectively), and more variation was explained by soil resource variables than topographic variables using either phylogenetic beta diversity metric. We also found that patterns of phylogenetic beta diversity expressed as nearest neighbor distance were consistent with previously observed patterns of niche similarity among congeneric species pairs in these plots. These results indicate the importance of phylogenetic signal in local habitat niches in shaping the phylogenetic structure of tropical tree communities, especially at the level of close phylogenetic neighbors, where similarity in habitat niches is most strongly preserved

LEAF ADAPTABILITY OF lWO NON·TIMBER FOREST SPECIES Caryota urens L. AND Elettaria carrlamomum VAR. MAJOR PLANTED IN THE Pinus caribaea ENRICHMENT BUFFER ZONE IN SINHARAJA MAB RESERVE, SRI LANKA

Caryota urens L. and Elettaria cardamomum var. major are indigenous non-timberspecies which are used as market or sustainable goods and services for human orindustrial consumption. Both species thrive well in disturbed forest areas in the southwesternpart of Sri Lanka. Being understorey species, the growth of these species areaffected by sun light which is highly variable and often limiting resource in the forest.In a Pinus enrichment study established in 1991, leaf anatomical adaptability of these twospecies after 12 years of initial establishment under the Pinus buffer zone of the SinharajaMAB .reserve was investigated. Different light levels in the study area were created bythinning Pinus trees at different densities.Lower epidermis of C. urens showed highest (7.75 %) and lowest (6.35 %) stomatalindices in 2 pine rows removed treatment (2R) and 5 pine rows removed treatment (5R)respectively. Corresponding values for E. cardamomum were 6.00 % (highest) in theclosed canopy control (CU) and 5.22 % (lowest) in 1 pine row removed treatment (lR).The highest thickness of C. urens leaf cuticle (0.2611 ±0.02), leaf blade (22.2711 ±2.l4),upper epidermis (1.7511 ±0.10), lower epidermis (1.8311 ±0.06), palisade layer (6.2511±0.87) and spongy mesophylliayer (11.7411 ±1.30) were observed in 5R treatment thatreceived relatively high light levels than other treatments.E. cardamomum leaves showed highest thickness of leaf blade (22.4311 ±O.88), lowerepidermal layer (2.1211 ±O.ll), spongy mesophyll layer (10.3211 ±O.57) in 3 pine rowsremoved treatment (3R). The highest cuticle thickness (0.2311 ±O.OI) was recordered in 3pine rows under planting treatment (3U) while lR treatment showed highest upperepidermal layer thickness of 2.2111 ±0.15. Palisade layer was highest (4.74J! ±0.55) inCU.Results revealed that C. urens shows leaf adaptability to grow under relatively high sunlight levels (5R treatment) while E. cardamomum shows most of the leaf adaptabilitycharacters to grow under moderate light levels (3R treatment).The knowledge gained by this study is useful to recommend the optimum lightrequirements in terms of leaf anatomical traits of the study species.

HABITAT UTILISATION PATTERN OF Lantana camara IN UDAWALAWE NATIONAL P,ARK IN SRI LANKA

Lantana camara, of the family Verbenaceae is native to the tropical and sub tropicalregions of Central and South America. It grows in a wide range of habitats, from exposeddry hillsides to wet heavily shaded gullies. It was introduced to Sri Lanka in 1926 throughthe Royal Botanic Gardens and currently it has spread across the island significantly andhas become an invasive species in most of the habitats including the Udawalawe NationalPark. Through its invasive nature it has become a threat to fauna and flora of the Park dueto habitat invasion and loss. Therefore, the main objective of this study is to assess thehabitat utilization pattern of L. camara in the Park.For this, the extent of the species in the 3 selected habitats of the Park ie. Scrub grassland,Medium height scrub and Scrub forest transitions was studied using field survey using GPSmstruments. This data was mapped subsequently in order to get an overall idea of thehabitat utilization of the species in the Park. Further, the relative abundance of this speciesin each of the 3 habitats selected was studied using 10 x 10 m quadrates replicated 3 timesfor better accuracy. Field observations were carried out in L. camara trees on the followingparameters; presence of flowers and seeds on the tree, time taken to start flowering, seeddispersal mechanism, seed germination and spreading ability. Seeds were also germinatedin the green house of the University of Sri Jayewardenepura to assess the germinationperiod and germination energy.The results showed significant variation was observed between the habitat types sampled inthe extent of L. camara; the figures being 75% in the Scrub grassland, 65% in Mediumheight scrub and 45°;(, being in the Scrub forest transitions. When these results weremapped, it showed 20% invasion of L. ccmara in the Park especially into the vegetationtypes sampled in the study ..When taken as an overview, the main road and Veheragolla,Seenuggala, Mau ara, Thirnbiriyarnankada and 5th mile post are the most densely andcontinuously distributed areas.The relative abundance and height of L. camara was highest in the Medium height scrubgrassland (92%) while the lowest was observed in the Scrub forest transitional area (87%).The species produced large number of flowers and seeds (20 - 30/cluster). The germinationability of the plant was very high (85 (~,O Therefore, the present study highlights theinvasive nature of the plant especially in open scrub areas and the need to effectivelymange the same to secure the biodiversity of the Park.