Lower Montane Forest Research Articles

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.

Diversity and distribution of termite assemblages in montane forests in the Knuckles Region, Sri Lanka

This study was conducted in the Knuckles Forest Region in central Sri Lanka, and investigated how termite species richness, abundance and functional group diversity vary in different montane forest types and identified the likely causes of this pattern. Termite diversity declined with increased elevation, with upper montane forests recording a single endemic species, Postelectrotermes militaris Desneux. Transect sampling in lower montane forests yielded 26 species, with a higher number from dry forests (22 species) than from wet forests (15 species). Species specificity also was high in dry forests (11 species) compared with wet forests (four species). Termite abundance did not show a distinct trend in dry and wet forests. Live-wood termites were present only in upper montane and high-altitude lower montane dry forests. Wet forests had a higher relative abundance (78%) but not species richness (40%) of soil and soil–wood interface feeders. In dry forests, both species richness (82%) and abundance (88%) of fungus-growing wood feeders were higher. The study suggests that key drivers of the species distribution pattern are low temperature and differing forest floor conditions. In the upper montane forest floor where earthworms dominate, wet soil and damp, woody litter riddled with beetles are not favourable for termites. In lower montane wet forests, moist, thick decomposing leaf litter and in dry forests, drier, relatively undecomposed leaf litter with many dry sticks and branches support species with specific food habits.

Forests of the tropical eastern Andean flank during the middle Pleistocene

Inter-bedded volcanic and organic sediments from Erazo (Ecuador) indicate the presence of four different forest assemblages on the eastern Andean flank during the middle Pleistocene. Radiometric dates (40Ar–39Ar) obtained from the volcanic ash indicate that deposition occurred between 620,000 and 192,000years ago. Examination of the organic sediment composition and the fossil pollen, wood and charcoal it contains provides insight into depositional environment, vegetation assemblage and fire history. The high organic content and abundance of macro fossils found throughout the sediment suggest that during the period of deposition the local environment was either a swamp or a shallow water body. The correlation of fire activity (peaks in charcoal abundance) with volcanic ash deposits through most of the record suggests that volcanoes were the main source of ignition. The low abundance of grass (typically <10%) throughout the sedimentary sequence along with the low abundance of other taxa indicative of open vegetation suggests the persistence of forest at Erazo. Four types of forest assemblage were identified (with the first taxa as the most dominant): i) Alnus-Arecaceae, ii) Miconia-Melastomataceae/Combretaceae-Moraceae/Urticaceae, iii) Arecaceae-Alnus, and iv) Podocarpus with Oreopanax sp. and Melastomataceae/Combretaceae. Changes in the forest floristic composition indicate high vegetation turnover and reassortment of taxa between upper and lower montane forests during the middle Pleistocene as well as the persistence of forest cover.

Diversity and distribution of the bryophyte flora in montane forests in the Chapada Diamantina region of Brazil

Bryophytes constitute an important component of tropical rain forests, which provide microhabitats favorable for their establishment. Bryophytes are also quite responsive to changes in microclimate, which makes them good bioindicators. This study aimed to determine the diversity and distribution of bryophytes in upper and lower montane forests of the Chapada Diamantina region of the state of Bahia, Brazil. To that end, we studied community aspects such as richness, diversity, substrates colonized, life forms and floristic similarity between areas and regions. In 2007 and 2008, we collected specimens from six forest sites, located from the north to the south of the Chapada Diamantina region. We identified a total of 205 infrageneric taxa. In comparison with the lower montane forests, the upper montane forests presented higher diversity and species richness, as well as greater numbers of substrates colonized, life form types, species of restricted geographic distribution and species typical of shaded areas. We also found low similarity in the species composition, the populations of the upper and lower montane forests forming two large and distinct groups. Although presenting relatively high floristic homogeneity among themselves, the Chapada Diamantina areas presented little similarity with those of the Atlantic Forest. This can be explained by the differences between the two regions in terms of environmental conditions, precipitation, seasonality, elevation and continentality.

A new montane species of Philautus (Amphibia: Anura: Rhacophoridae) from western Sarawak, Malaysia, Borneo.

A new species of Philautus is described from western Sarawak. The new species was collected in lower montane forest in two national parks in Sarawak and recorded from another park. It differs from its congeners by a unique combination of morphological characters, including a long, acuminate snout, long legs, and comparatively extensive toe webbing. The advertisement call of the new species differs from all calls of other species that have been analyzed so far. Comparison of the mitochondrial 16S rRNA gene sequence corroborates its distinct specific status.

Environmental Impacts of Large‐Scale Oil Palm Enterprises Exceed that of Smallholdings in Indonesia

AbstractThe expansion of large‐scale oil palm plantations in Indonesia has taken a heavy toll on forests, biodiversity, and carbon stocks but little is known about the environmental impacts from the smallholder sector. Here, we compare the magnitude of forest and carbon loss attributable to smallholdings, private enterprises, and state‐owned oil palm plantations in Sumatra. During 2000–2010, oil palm development accounted for the loss of 4,744 ha of mangrove, 383,518 ha of peat swamp forest, 289, 406 ha of lowland forest, and 1,000 ha of lower montane forest. Much of this deforestation was driven by private enterprises (88.3%) followed by smallholdings (10.7%) and state‐owned plantations (0.9%). Oil palm‐driven deforestation in Sumatra resulted in 756–1,043 Mt of total gross carbon dioxide emissions, of which ∼90% and ∼9% can be attributed to private enterprises and smallholdings, respectively. While private enterprises are responsible for the bulk of environmental impacts, the smallholder oil palm sector exhibits higher annual rates of expansion (11%) compared to private enterprises (5%). Both sectors will need careful monitoring and engagement to develop successful strategies for mitigating future environmental impacts of oil palm expansion.

How heterogeneous are the cloud forest communities in the mountains of central Veracruz, Mexico?

The montane forest in central Veracruz, Mexico is a hotspot of biodiversity. We asked whether lower and upper montane forests could be distinguished in this ecoregion. Variables of vegetation and seasonality in precipitation were tested across 14 sites between 1,250- and 2,550-m elevations. A total of 1,639 individuals and 128 tree species was recorded. There was a unimodal pattern in the richness of species, genera, and families; their richness was positively correlated with precipitation in the wettest quarter of the year, though there were no differences in the basal area and density. Rarefaction, species turnover, nonmetric multidimensional scaling, and a cluster histogram suggest two major groups: lower elevation forests that are less diverse, have low beta diversity and are more similar in composition, with Clethra macrophylla, Liquidambar styraciflua, and Quercus lancifolia as indicator species; and higher elevation forests that are more diverse, have high species turnover, and include forests with Quercus corrugata and Prunus rhamnoides, and forests with Fagus grandifolia, Persea americana, and Ternstroemia sylvatica as indicator species. However, other communities (an Oreomunnea mexicana at the upper site, and a limestone site in the lower forests), exemplify the high regional heterogeneity. We conclude that elevation and seasonality in precipitation produce a directional change in richness and indicator species, but not in vegetation structure. Lower montane forests differed from cloud forests at upper elevations. However, other factors should be included—mainly biogeographic affinities, historic and recent anthropogenic disturbance—to conclusively distinguish them. Montane forest can still be considered very heterogeneous and very high in beta diversity.

Vegetation of Alejandro Selkirk Island (Isla Masafuera), Juan Fernández Archipelago, Chile

We analyzed the vegetation of Alejandro Selkirk Island using the Zürich-Montpellier approach for taking relevés and subsequent classification by a multivariate approach and manual refinement. The resulting vegetation table demonstrates patterns of dominance and variation and the resulting vegetation units that were mapped onto aerial photographs to produce a vegetation map. Additional observations of several inaccessible sectors were gained from photos taken during a boat trip around the island. These results are combined in a colored map that shows the following vegetation units: (1) Dicksonia externa Tree Fern Community (upper montane forest); (2) Lophosoria quadripinnata Fern Community; (3) Fern-Grassland Mosaic; (4) Myrceugenia schulzei Forest (lower montane forest); (5) Anthoxanthum-Nassella Grassland; (6) Coastal Grassland with Juncus procerus; (7) Open Grassland (including Coastal Herb Communities); (8) Rocks, Erosional Zones; and (9) Cultivated and Escaped Plants Near the Settlement. In some cases these units consist of several communities together, often forming mosaic patterns where detailed resolution is not practicable. Unit 7, Open Grassland, has been applied to all areas with a plant cover below 40%, and unit 8, Rocks, Erosional Zones, indicates no or scarce vegetation (cover notably below 10%). Some plant assemblages cannot be shown on the map: (a) the small clusters of Drimys confertifolia; (b) the mostly linearly or patchily arranged Gunnera masafuerae community; (c) several plant assemblages found in the canyons; and (d) the Histiopteris incisa clusters between the tree ferns and tall ferns. We discuss composition of the observed plant communities, especially regarding alien impact, and compare our findings with those on Robinson Crusoe, the largest island of the archipelago.

A new species of masked-owl (Aves: Strigiformes: Tytonidae) from Seram, Indonesia.

We describe a new species of masked-owl from the lower montane forest of Seram, one of the largest islands in the Moluccas of eastern Indonesia, for which we propose the name Tyto almae (Seram Masked-Owl), sp. nov. Molecular (mitochondrial cyt-b) differences show that Tyto sororcula of Buru and Tanimbar is closely related to T novaehollandiae of Australia and New Guinea (-1% uncorrected pairwise distance), and that Tyto almae of Seram differs by -3% (uncorrected pairwise distance) from both of them. These differences are further corroborated by morphology and colouration. Although a photograph from Seram published in 1987 had already established the presence of a Tyto owl on the island, ours represents the first specimen of this species. The bird was mist-netted in wet, mossy lower montane forest at an elevation of 1,350 m. No further observations of the owl were made during four weeks of fieldwork in Seram.

Effect of land-use and elevation on microbial biomass and water extractable carbon in soils of Mt. Kilimanjaro ecosystems

Microbial biomass carbon (MBC) and water-extractable organic carbon (WOC) – as sensitive and important parameters for soil fertility and C turnover – are strongly affected by land-use changes all over the world. These effects are particularly distinct upon conversion of natural to agricultural ecosystems due to very fast carbon (C) and nutrient cycles and high vulnerability, especially in the tropics. The objective of this study was to use the unique advantage of Mt. Kilimanjaro – altitudinal gradient leading to different tropical ecosystems but developed all on the same soil parent material – to investigate the effects of land-use change and elevation on MBC and WOC contents during a transition phase from dry to wet season. Down to a soil depth of 50cm, we compared MBC and WOC contents of 2 natural (Ocotea and Podocarpus forest), 3 seminatural (lower montane forest, grassland, savannah), 1 sustainably used (homegarden) and 2 intensively used (maize field, coffee plantation) ecosystems on an elevation gradient from 950 to 2850m a.s.l. Independent of land-use, both MBC and WOC strongly increased with elevation on Mt. Kilimanjaro corresponding to ecosystem productivity and biodiversity. Through the agricultural use of ecosystems MBC and WOC contents decreased – especially in surface layers – on average by 765mgkg−1 for MBC and 916mgkg−1 for WOC, compared to the respective natural ecosystems. The decrease with depth was highest for forests>grasslands>agroecosystems and also was positively correlated with elevation. We conclude that MBC and WOC contents in soils of Mt. Kilimanjaro ecosystems are highly sensitive to land-use changes, especially in topsoil. The MBC and WOC contents were considerably reduced even in sustainable agricultural systems. Since MBC and WOC are very fast reacting and sensitive C pools, we expect a decrease in other soil C pools accompanied by a strong decrease in fertility and productivity due to changes in land use from natural to agricultural ecosystems.

Trapping pollen in the tropics — Comparing modern pollen rain spectra of different pollen traps and surface samples across Andean vegetation zones

The analysis of modern pollen rain is an important prerequisite for detailed and comprehensive studies on fossil pollen assemblages, as it is necessary for obtaining valuable information about present pollen spectra in a more quantitative way. At present, several sampling media are used for modern pollen rain collection in tropical environments, without knowing a lot about their trapping properties. We compared modern pollen rain spectra of different pollen rain sampling media along an altitudinal gradient from ca. 1000 to ca. 3300m a.s.l. in southern Ecuador. The vegetation types covered are premontane forest, lower montane forest, upper montane forest and páramo. Pollen assemblage composition, representation, diversity and palynological abundance in the modern pollen spectra of Behling traps, modified Oldfield traps, reference traps and soil samples were assessed in comparison to the vegetation. All sampling media showed distinguishable pollen spectra for each vegetation type. For the páramo, the most characterising taxa are Poaceae and Melastomataceae, accompanied by other, less frequent taxa such as Arcytophyllum, Valeriana and Ericaceae. The pollen spectrum of the upper montane forest is dominated by Melastomataceae, Hedyosmum and Weinmannia. The lower montane and premontane forests both have similar spectra, with high proportions of Moraceae/Urticaceae, Melastomataceae, Alchornea and Cecropia. Soil samples had a bias towards an over-representation of pollen and spore taxa with a thick exine, such as Poaceae, whereas taxa with fragile pollen grains, as Moraceae/Urticaceae, were represented to a lesser extent than in the pollen traps. Behling traps and modified Oldfield traps show similar patterns in taxa composition, pollen accumulation rates and pollen taxa proportions, as well as in representation of pollen spectra in comparison with the vegetation. However, especially in the páramo samples, modified Oldfield traps were disintegrated after one year in the field, due to temporarily dry and windy conditions, as well as strong radiation. We therefore recommend the use of Behling traps for the collection of modern pollen rain in areas with open vegetation, which are subjected to drought periods and strong radiation. In forested areas, modified Oldfield and Behling traps show similar results.

Palaeoecological evidence for Holocene environmental change from the Virunga volcanoes in the Albertine Rift, central Africa

This study presents two new, well-dated sedimentary pollen and charcoal records from high-altitude crater sites in the Virunga volcanoes, located in the Albertine Rift, central Africa, currently part of one of the world's most biodiverse areas. Here we argue that Holocene vegetation changes in a ca 8000-year palaeoenvironmental record from a crater swamp at an altitude of 3474 m and a ca 2800-year record from a crater lake at an altitude of 4127 m are linked to variations in both climate and human activity. Climatic changes during the mid- to late Holocene are reflected in the high-altitude sites and more widely in adjacent parts of the Albertine Rift. Vegetation changes, comprising a decline in Ericaceous vegetation at ca 5000 cal yrs BP and subsequent expansion of Afroalpine vegetation, together with a later increase in taxa associated with lower montane forest (particularly Podocarpus), reflect increasing aridity during the mid- to late Holocene. Human-induced environmental change in the Virunga volcanoes is apparent only within the last millennium, despite the long history of human occupation of the area. Both study sites record significant forest clearance at ca 900 cal yrs BP, involving a reduction in lower montane forest taxa and increases in disturbance indicators. Changes in the composition of upper montane forest, and particularly the expansion of Hagenia, are possibly linked to anthropogenic-induced changes in the fire regime, and are apparent from ca 900 cal yrs BP. Human-induced environmental modification from the early part of the last millennium, likely associated with onset of the Late Iron Age, appears to have extended to high altitudes. The importance of natural, long-term climate change as a major cause of environmental change in the Albertine Rift has been eclipsed within the last millennium by human-induced environmental effects.

DNA sequence data reveal a subfamily-level divergence within Thamnophilidae (Aves: Passeriformes)

The Thamnophilidae is a diverse radiation of insectivorous passerine birds that comprises nearly 220 species and is mostly restricted to the lowlands and lower montane forests of the Neotropics. Current classification within Thamnophilidae relies primarily on morphological variation, but recent incorporation of molecular and vocal data has promoted changes at various taxonomic levels. Here we demonstrate that the genus Terenura is polyphyletic because Terenura callinota, T. humeralis, T. spodioptila, and T. sharpei are phylogenetically distant from the type species of the genus, Terenura maculata. More importantly, the former four species are not particularly closely related to any other thamnophilids and represent a clade that is sister to all other members of the family. Because no genus name is available for this previously undetected lineage in the Thamnophilidae, we describe the genus Euchrepomis for callinota, humeralis, spodioptila, and sharpei, and erect the subfamily Euchrepomidinae. We discuss the taxonomic and evolutionary significance of this divergent lineage. This study highlights the importance of taxonomic coverage and the inclusion of type taxa to redefine classifications to reflect accurately evolutionary relationships.

Responses of nitrous oxide fluxes and soil nitrogen cycling to nutrient additions in montane forests along an elevation gradient in southern Ecuador

Tropical montane forests are commonly limited by N or co-limited by N and P. Projected increases in N deposition in tropical montane regions are thought to be insufficient for vegetation demand and are not therefore expected to affect soil N availability and N2O emissions. We established a factorial N- and P-addition experiment (i.e., N, P, N + P, and control) across an elevation gradient of montane forests in Ecuador to test these hypotheses: (1) moderate rates of N and P additions are able to stimulate soil-N cycling rates and N2O fluxes, and (2) the magnitude and timing of soil N2O-flux responses depend on the initial nutrient status of the forest soils. Moderate rates of nutrients were added: 50 kg N ha−1 year−1 (in the form of urea) and 10 kg P ha−1 year−1 (in the form of NaH2PO 4 . 2H2O) split in two equal applications. We tested the hypotheses by measuring changes in net rates of soil–N cycling and N2O fluxes during the first 2 years (2008–2009) of nutrient manipulation in an old-growth premontane forest at 1,000 m, growing on a Cambisol soil with no organic layer, in an old-growth lower montane forest at 2,000 m, growing on a Cambisol soil with an organic layer, and an old-growth upper montane rainforest at 3,000 m, growing on a Histosol soil with a thick organic layer. Among the control plots, net nitrification rates were largest at the 1,000-m site whereas net nitrification was not detectable at the 2,000- and 3,000-m sites. The already large net nitrification at the 1,000-m site was not affected by nutrient additions, but net nitrification became detectable at the 2,000- and 3000-m sites after the second year of N and N + P additions. N2O emissions increased rapidly following N and N + P additions at the 1,000-m site whereas only smaller increases occurred at the 2,000- and 3,000-m sites during the second year of N and N + P additions. Addition of P alone had no effect on net rates of soil N cycling and N2O fluxes at any elevation. Our results showed that the initial soil N status, which may also be influenced by presence or absence of organic layer, soil moisture and temperature as encompassed by the elevation gradient, is a good indicator of how soil N cycling and N2O fluxes may respond to future increases in nutrient additions.

Nutrient stocks and phosphorus fractions in mountain soils of Southern Ecuador after conversion of forest to pasture

Understanding pasture degradation processes is the key for sustainable land management in the tropical mountain rainforest region of the South Ecuadorian Andes. We estimated the stocks of total carbon and nutrients, microbial biomass and different P fractions along a gradient of land-uses that is typical of the eastern escarpment of the Cordillera Real i.e., old-growth evergreen lower montane forest, active pastures (17 and 50 years-old), abandoned pastures 10 and 20 years old with bracken fern or successional vegetation. Conversion of forest to pasture by slash-and-burn increased the stocks of SOC, TN, P and S in mineral topsoil of active pasture sites. Microbial growth in pasture soils was enhanced by improved availability of nutrients, C:N ratio, and increased soil pH. Up to 39 % of the total P in mineral soil was stored in the microbial biomass indicating its importance as a dynamic, easily available P reservoir at all sites. At a 17 years-old pasture the stock of NH4F extractable organic P, which is considered to be mineralisable in the short-term, was twice as high as in all other soils. The importance of the NaOH extractable organic P pool increased with pasture age. Pasture degradation was accelerated by a decline of this P stock, which is essential for the long-term P supply. Stocks of microbial biomass, total N and S had returned to forest levels 10 years after pasture abandonment; soil pH and total P 20 years after growth of successional bush vegetation. Only the C:N ratio increased above forest level indicating an ongoing loss of N after 20 years. Soil nutrient depletion and microbial biomass decline enforced the degradation of pastures on the investigated Cambisol sites.

The Distribution of the ferns Gleicheniaceae in Peninsular Malaysia

A study on fern family Gleicheniaceae was carried out for Peninsular Malaysia. A total of 14 species including 10 varieties in 4 genera was identified and recorded, genus Dicranopteris (4 species, 7 varieties), Diplopterygium (5 species), Gleichenia (3 species) dan Sticherus (3 species, 3 varieties). These ferns were collected from the fringes of the Lowland Dipterocarp Forest (LDF), Hill Dipterocarp Forest (HDF), Lower Montane Forest (LMF) and Upper Montane Forest (UMF). Four species and 3 varieties were found to be widely distributed over 3 types of vegetation, the LDF, HDF and LMF. Three species were distributed over higher elevation from the HDF, LMF to UMF. One variety, Dicranopteris linearis var. altissima was only recorded from the LDF, whilst Diplopterygium giganteum and Gleichenia dicarpa were recorded only in the UMF. Dicranopteris linearis and Sticherus truncatus were found to be the most widely distributed G. Rusea • L. Y. Chin • H. Omar • M. Muskhazli • Y. Umi Kalsom Biology Department, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia Haja Maideen School of Environmental and Natural Resources Science, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor, Malaysia G. Rusea ( ) Biology Department, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia e-mail: rusea@science.upm.edu.my species in this family whereby they could be found in all vegetation types. All species of Gleicheniaceae are terrestrial sun loving ferns and grew well on poor clay soils or poor nutrient soils. In fact, these ferns required small amount of mineral substances for growth. Members of this family mostly form thickets in open places, to which they are adapted to by their creeping rhizomes and the indefinite growth in length of scrambling or climbing fronds.

Phylogeny and systematics of Melanesia’s most diverse gecko lineage (Cyrtodactylus, Gekkonidae, Squamata)

Oliver, P.M., Richards, S.J. &amp; Sistrom, M. (2012). Phylogeny and systematics of Melanesia’s most diverse gecko lineage (Cyrtodactylus, Gekkonidae, Squamata). —Zoologica Scripta, 41, 437–454.The systematics and biogeographical history of the diverse fauna of New Guinea and surrounding islands (Melanesia) remain poorly known. We present a phylogeny for 16 of the 21 recognised Melanesian bent‐toed geckos in the genus Cyrtodactylus based on mitochondrial sequence data. These analyses reveal two divergent lineages of Cyrtodactylus within Melanesia. One includes a single recognised species with clear affinities to sampled taxa from Asia. The other comprises a relatively diverse radiation (likely 30+ species), not closely related to sampled extralimital taxa and centred on the Melanesian region (including Australia). Many taxa within this second lineage are endemic to islands surrounding New Guinea, and dispersal and speciation on peripheral islands appears to have played an important role in the accumulation of species diversity within this clade. In contrast, little diversity is centred upon montane areas, although we do identify at least one lineage closely associated with hill and lower montane forest that probably dates to at least the late Miocene. Our phylogenetic analyses also reveal numerous divergent lineages that require taxonomic attention, including at least two widespread taxa that are likely to be composite, additional specimens of Cyrtodactylus capreoloides (until recently known only from the holotype) and several divergent and completely novel lineages, two of which we introduce herein: Cyrtodactylus arcanus sp. n. and Cyrtodactylus medioclivus sp. n.

Book review: Tackling thorny issues in seasonally dry tropical forests

news and update ISSN 1948‐6596 book review Tackling thorny issues in seasonally dry tropical forests The ecology and conservation of seasonally dry forests in Asia, by William J. McShea, Stuart J. Davies and Naris Bhumpakphan (editors) 2011, Smithsonian Institution Scholarly Press, 418 pp. ISBN: 978‐1‐935623‐02‐1 Price: $69.95 / £44.95 (Hardback); http://www.scholarlypress.si.edu/ Seasonally dry tropical forests: ecology and conservation, by Rodolfo Dirzo, Hillary S. Young, Harold A. Mooney and Gerardo Ceballos (editors) 2011, Island Press, 391 pp.ISBN: 978‐1‐59726‐703‐8/978‐1‐59726‐704‐5 Price: $95.00 (Hardback)/$50.00 (Paperback); http://islandpress.org/ The first difficulty in reviewing (and I presume writing) any book on seasonally dry tropical for‐ ests (SDTF) is to come to some understanding as to what SDTF actually are. I hazard a guess that what is a seasonally dry tropical forest to one per‐ son is a seasonal rain forest to another. I myself have recently treated ‘seasonally dry tropical for‐ est’ formations as various types of ‘seasonal rain forest’ (Ghazoul & Sheil, 2010). What is clear is that aseasonal tropical wet forests grade almost imperceptibly into seasonally dry evergreen for‐ est, variably deciduous forest and, ultimately, xe‐ rophytic woodland at the other extreme. Imposing clear‐cut system definitions is always going to be problematic, but it is the nature (and necessity) of human enquiry to impose some sort of classifica‐ tion system on hopelessly complex realities. In this vein two recent edited books on Neotropical (Dirzo et al.) and Asian (McShea et al.) forests de‐ fine SDTF as tropical forests with predictable, regular dry seasons lasting 4‐6 (Neotropics) or 2‐6 months (Asia), while also recognising variations on this theme. It is not so much the duration or inten‐ sity of the dry season that matters, but rather the seasonal water stress that plants are subjected to, and this is as much a function of local topography, soil and disturbance history as it is of climate. Thus in Asia SDTF can occur alongside wet ever‐ green formations in a mosaic of different vegeta‐ tion types, adding to the complexities of distin‐ guishing and mapping SDTF. Both these books begin similarly, with a couple of chapters on floristic composition and biogeography of seasonally dry tropical forests in each respective region. In the Neotropics Linares‐ Palomino et al. identify close floristic affinities among isolated SDTF regions that are distributed across a formerly hypothesised ‘Pleistocene Arc’ of SDTF that extends from Argentina in the south through Paraguay and across Brazil in the north. The Andean dry forests might represent an exten‐ sion of this arc, although the data on this point are ambiguous. Yet these authors argue that there is little evidence for a wide‐ranging Pleistocene SDTF formation, citing long‐distance dispersal events to explain the distribution of widespread species. The floristic ordination of continental Southeast Asian SDTF conducted by Bunyavejchewin et al. separates formations by elevation, topography, soil chemistry and soil physical features, all of which are related to soil water‐holding capacity, as well as the length of the dry season. A striking feature of SDTF and other tropical forests in Asia is their abundance of trees belonging to the Dip‐ terocarpaceae, yet some formations (e.g. mixed deciduous forests and lower montane forests) are notable by the near absence of dipterocarps. A biogeographic approach might provide some in‐ sights into such patterns because the Asian mixed deciduous and lower montane forests are domi‐ nated largely by families that are thought to have warm‐temperate Eurasian origins (e.g. Fagaceae, Lythraceae), while the dipterocarps originated in the southern hemisphere (Gondwana) and colo‐ nised the Asian tropics via India’s collision with Asia around 50 Mya. A fascinating chapter on the evolution of dry forest gingers by John Kress is unfortunately not placed in the context of the dis‐ tribution of forest formations outlined in the ear‐ lier chapters. The central defining feature – a predictable dry season – shapes phenological, behavioural, © 2012 the authors; journal compilation © 2012 The International Biogeography Society — frontiers of biogeography 3.4, 2012

Epiphytic biomass of a tropical montane forest varies with topography

Abstract:The spatial heterogeneity of tropical forest epiphytes has rarely been quantified in terms of biomass. In particular, the effect of topographic variation on epiphyte biomass is poorly known, although forests on ridges and ravines can differ drastically in stature and exposure. In an Ecuadorian lower montane forest we quantified epiphytic biomass along two gradients: (1) the twig–branch–trunk trajectory, and (2) the ridge–ravine gradient. Twenty-one trees were sampled in each of three forest types (ridge, slope, ravine positions). Their epiphytic biomass was extrapolated to stand level based on basal area–epiphyte load relationships, with tree basal areas taken from six plots of 400 m2 each per forest type. Our results document the successional addition and partial replacement of lichens by bryophytes, angiosperms and finally dead organic matter along the twig–branch–trunk trajectory. Despite having the highest tree basal area, total epiphytic biomass (mean ± SD) of ravine forest was significantly lower (2.6 ± 0.7 Mg ha−1) than in mid-slope forest (6.3 ± 1.1 Mg ha−1) and ridge forest (4.4 ± 1.6 Mg ha−1), whereas maximum bryophyte water storage capacity was significantly higher. We attribute this pattern to differences in forest dynamics, stand structure and microclimate. Although our study could not differentiate between direct effects of slope position (nutrient availability, mesoclimate) and indirect effects (stand structure and dynamics), it provides evidence that fine-scale topography needs to be taken into account when extrapolating epiphytic biomass and related matter fluxes from stand-level data to the regional scale.

Landscape effects on structure and species composition of tabonuco forests in Puerto Rico: Implications for conservation

We studied the structure and species composition of nine residual forest stands of Dacryodes excelsa (tabonuco), a dominant vegetation type in the moist and wet lower montane forests of the Caribbean. The stands were scattered over three different landscapes with different degrees of anthropogenic disturbance: forested, shade coffee, and tobacco. We compared our results with data from undisturbed stands inside a protected and forested landscape to see how the type of landscape that surrounded them affected the structure and species composition of the residual forest stands. In the process we sought conservation lessons that would help restore degraded tabonuco forests to original conditions. Tree density, basal area, and species density all increased with elevation. We found 98 tree species, including 50 of the 83 species that we identified as belonging to undisturbed tabonuco forests (including 13 of 18 endemic tree species), 41 tree species not reported for undisturbed tabonuco forests, eight primary forest species, and six introduced species. When ordered by species Importance Value by site, the stands in nine sites separated into three general groups corresponding to landscape type: (1) Heavily used for tobacco production. (2) Shade coffee, and (3) Forested. The importance of introduced species increased, and the abundance of tabonuco forest indicator species and endemic species decreased with increased anthropogenic disturbances. When restoring tabonuco forests, it is necessary to understand the landscape forces that influence the species composition of these forests. It appears that particular species combinations are natural outcomes of the level of anthropogenic activity in the landscape and reversing those tendencies might be impractical or too costly.