Beta diversity of geometrid moths (Lepidoptera: Geometridae) in an Andean montane rainforest

Abstract. Turnover in species composition of the extremely species‐rich family Geometridae (Lepidoptera) was investigated along an elevational gradient ranging from 1040 m to 2677 m above sea level. Moths were sampled using weak light traps (30 W) in three field periods in 1999 and 2000 in an Andean montane rainforest in the province of Zamora‐Chinchipe in southern Ecuador. A total of 13 938 specimens representing 1010 species were analysed. Similarities of ensembles of all geometrid moths and of the subfamilies Ennominae and Larentiinae were calculated using the NESS index (with m_max). Ordinations performed using nonmetric multidimensional scaling (NMDS) and correspondence analysis depicted a gradual change of the ensembles along the altitudinal gradient. Extracted ordination scores significantly correlate with altitude (?0.97 ≤ r ≤ ?0.95, P < 0.001) and with ambient air temperature (0.93 ≤ r ≤ 0.97, P < 0.001). Temperature is therefore assumed to be the most important abiotic determinant responsible for the species turnover among the moths. Matrix correlation tests were performed in order to compare faunal matrices with matrices derived from available environmental factors. Both tree diversity and vegetation structure significantly correlate with faunal data, but tree diversity explains considerably more of the data variability (range: Mantel r = 0.81–0.83, P < 0.001) than vegetation structure (range: Mantel r = 0.35, P < 0.005 to r = 0.43, P < 0.001). Tree diversity also changes gradually and scores of the first NMDS dimension are highly significantly correlated with altitude (r = 0.98, P < 0.001). A common underlying factor such as ambient temperature might also be responsible for such vegetation changes. Additionally, simulated model data was developed that assumed a constant turnover of moth species and equal elevational ranges of all species involved. Despite the simplicity of the models, they fit empirical data very well (Mantel r > 0.80 and P < 0.001 in all models).     

滇南勐宋热带山地雨林木质藤本多样性研究

调查滇南勐宋山地雨林沟谷与坡地两种生境中木质藤本种的丰富度、径级分布、攀缘方式以及样地中被藤本缠绕的树木(dbh≥5cm)的数量和比率。结果表明:沟谷与坡地胸径≥1cm的木质藤本平均密度分别为95.7株/0.1hm2、57株/0.1hm2。调查样地内木质藤本共64种,隶属30个科。茎缠绕是最主要的攀缘方式,占总个体数的57%,卷须缠绕种所占比重最小,仅占3%;沟谷与坡地所调查树木被木质藤本缠绕的比例分别为43.7%和28.6%。与亚洲其它热带地区森林相比,勐宋地区藤本的多样性低,但是木质藤本的密度相当高,并且在一些样地中出现了大型木质藤本,这些可能与该地区森林的演替状态有关。     

Elevation gradients of lemur abundance emphasise the importance of Madagascar’s lowland rainforest for the conservation of endemic taxa

1. Elevation gradients correlate with changes in several environmental conditions and are known to be related to animal abundance. Animals in regions with a naturally limited extent of lowland rainforest are expected to have evolved adaptations to intermediate elevations that provided a stable environment during their evolution.
2. Since the lowland rainforest of Madagascar has a limited extent and suffers from increasing anthropogenic pressure, it is essential to understand how well species tolerate intermediate and high elevations. In this study, we aim to quantify the relationship between lemur abundance and elevation in the eastern rainforest of Madagascar.
3. We correlated abundance data on 26 lemur species (10 genera), including 492 records from 26 studies, with elevation. We analysed the consistency of correlations across species with a meta-analytical approach. We controlled for species’ body mass, elevational range and median elevation. We then ran generalised linear mixed models to determine whether lemur abundance was related to elevation, body mass, plant productivity and anthropogenic disturbance.
4. Overall, the abundance of lemur species in Malagasy rainforests was negatively correlated with elevation, and species occupying broader elevational ranges showed stronger correlations. Body mass was not related to species’ tolerance of high elevations. Even though several lemur species are able to occupy the entire elevation gradient, the few remaining patches of lowland rainforests host lemur species at greater abundances than other sites. Abundance across species was negatively related to body mass, elevation and seasonality in plant productivity and positively related to plant productivity.
5. Despite the ecological flexibility of many lemur species, the remnant patches of lowland rainforests host the highest levels of lemur abundance and are key to lemur conservation. It is crucial to preserve this priority habitat both for biodiversity conservation and for our understanding of lemur adaptations.

     

Diversity and faunistics of small moths (Microlepidoptera) in Bornean rainforest

Abstract.

• 1 Samples of Microlepidoptera (including Pyraloidea) collected at light in mangrove forest, lowland mixed dipterocarp forest, and montane oak-laurel forest in Borneo are compared.
• 2 Diversity (Williams' alpha) is very high in lowland forest, with a value of 414; it is lower, 226, in montane forest and very much lower, 47, at the edge of mangrove forest.
• 3 There is some evidence that apparent diversity increases with accumulation of samples.
• 4 Samples from the three forest types have very few species in common and come from separate assemblages.
• 5 Pyraloidea in samples taken 1km apart in lowland forest represent an assemblage common to the two sites but Microlepidoptera samples appear to represent slightly different assemblages.
• 6 There are no abundant species in lowland or montane forest: species with more than ten individuals comprised less than 4% of the samples. Four common species in mangrove forest accounted for 34% of the sample.
• 7 The proportion of Tineoidea, Gelechioidea and Pyraloidea is lower in montane forest than in lowland forest, while that of Yponomeutoidea and Tortricoidea is higher.
• 8 Just eight families of Microlepidoptera account for 90% of the species in samples from all three forest types.
• 9 The number of species of moths in Borneo is suggested to be in excess of 8500.

     

Changes in function and temporal variation in a guild of gall‐parasitoids across a temperature gradient in Australian subtropical rainforest

Parasitoids play an important role in ecosystem functioning through their influence on herbivorous insect populations. Theoretical and experimental evidence suggest that increased species richness can enhance and stabilize ecosystem function. It is important to understand how richness‐driven functional relationships change across environmental gradients. We investigated how temperature affected the relationship between parasitoid richness and parasitism rate in a guild of gall‐parasitoids along an elevational gradient. We collected galls at 15 sites along five elevational gradients (between 762 m and 1145 m asl) on six occasions over a year. A total of 1902 insects, including 1593 parasitoids, were reared from 12 402 galls. Parasitism rate increased significantly with temperature on all sampling occasions, except December and February. We found a significant, positive richness–parasitism relationship. This relationship, however, was weaker at higher elevations which may be linked to decreased functional efficiency of parasitoids at lower temperatures. Temporal variability in parasitism rate and parasitoid richness were significantly related, regardless of temperature. A stable functional guild of this kind may provide a more reliable ecosystem service under environmental changes.     

Effects of selective logging on the arboreal ants of a Bornean rainforest

We examined the effect of selective logging and corresponding forest canopy loss on arboreal ant diversity in a tropical rainforest. Arboreal ants were collected from an unlogged forest plot and from forest plots selectively logged 14 years and 24 years earlier in Danum Valley, Sabah, Malaysia, using a canopy fogging method. Selective logging was associated with a significant decrease in canopy cover and an increase in understory vegetation density relative to unlogged forest. Our study showed that selective logging in primary forest might not dramatically decrease total species number and overall abundance of arboreal ants; however, it may influence the species composition and dominance structure of the ant community, accompanied by an increase in abundance of shrub‐layer species and trophobiotic species. In view of the results of this study, management techniques that minimize logging impact on understory vegetation structure are likely to help maintain the conservation value of logged forests for arboreal ants. Our results also suggest that accurate assessment of the impacts on biodiversity should not be based only on measurement of species number and overall abundance, but also on analysis of species composition and community structure.     

Resprouting of saplings following a tropical rainforest fire in north‐east Queensland,Australia

Abstract In 2002, fire burnt areas of Mesophyll‐ and Notophyll Vine Forest in the Smithfield Conservation Park near Cairns, Australia. We assessed the ability of rainforest plant species to persist through fire via resprouting. Natural rates of mortality and resprouting in unburnt areas were assessed for all saplings (stems < 2 m) via 13, 2 × 50 m belt transects, and compared to estimates of mortality and resprouting in 26 transects in burnt areas. We also tested the resprouting ability per‐individual stem of each species against all other stems with which it co‐occurred. Totals of 1242 stems (138 species) were sampled in burnt transects and 503 stems (95 species) in unburnt transects (total number of unique species = 169). There was no difference in the number of stems existing prior to the fire in burnt and unburnt areas when expressed on a per‐sample area basis. Resprouting from basal shoots and root suckers was significantly greater in burnt than in unburnt areas, but rates of stem sprouting were not different. In burnt areas 72 species were tested for resprouting ability and most (65/72) resprouted at similar rates. All species analysed contained individuals that resprouted. The resprouting response of five species was significantly lower, and in two species was significantly higher. For these species especially, fire may act as a mechanism altering relative abundances. The fire coincided with an extreme El Niño event. Current predictions indicate El Niño conditions may become increasingly common, suggesting fire events within rainforest could become more frequent. Resprouting as a general phenomenon of rainforest species, and differential resprouting ability between species should therefore be an important consideration in assessing the potential path of vegetation change in rainforests after fire.     

Measurement of tree diversity in the Nigerian rainforest

The diversity of trees 5 cm in diameter and above at breast height was studied at five sites within the Nigerian rainforest. The sites were Gambari, Oban, Omo, Owan and Sapoba forest reserves. Diversity was measured in terms of similarity and heterogeneity and explored at beta and gamma levels. Over 315 species were encountered during the study. In terms of species richness, there are 80, 226, 163, 137 and 159 species in Gambari, Oban, Omo, Owan and Sapoba, respectively. The occurrence of the species showed that, while 26 species are common to all the sites, 62, 17, 15, 8 and 6 species are restricted to Oban, Omo, Sapoba, Gambari and Owan, respectively. Ordination by detrended correspondence analysis indicated gradients along the first two axes. The first axis reflecting rainfall gradient which decreases from Oban through to Sapoba, Owan and Gambari. The second axis showed a separation of Omo, and Owan and Sapoba. This suggests a gradient of soil parent materials, the former site is on the basement complex while the latter is on the cretaceous rock. It is suggested that each forest should be managed based on its particular characteristics, such as species composition and abundance. Thus, forests with high species diversity but fewer numbers of individuals, such as in Oban, should be earmarked for conservation while species-rich forests with relatively more economic species, as in Sapoba and Omo, should be managed for sustained timber production. Floristically poor forest, such as those in Gambari and Owan, should be converted to plantations of fast growing species but with care taken to avoid exposing such sites to soil erosion.     

Mammal species richness and habitat use in rainforest and abandoned agricultural fields in Chiapas, Mexico

1. We evaluated the potential of small, isolated cornfields embedded in a large forest matrix as an appropriate compromise between conservation and sustainable development.
2. We examined the relationship between habitat structure and diversity with overall mammal species richness and abundance of six common small mammals in four 6-year-old abandoned cornfields (oldfields) and four continuous rainforest sites in the most speciose region in Mexico, the Selva Lacandona, Chiapas.
3. Species richness did not differ between forests and oldfields, indicating that forest-dependent mammals penetrate oldfields of size 0·9–2·9 ha, presumably because forest cover and resources are nearby. Even species which strongly selected forest habitat, such as H. desmarestianus and D. marsupialis , were present in oldfields, and only the latter showed a significant decline in the number of captures as a function of distance from forest edge.
4. The Lacandon Indian use of the land for agriculture in the form of small (> 3 ha) agricultural plots embedded in a large forest matrix increases spatial heterogeneity and promotes mammal diversity.
5. Those small plots (in agricultural production terms) are intermediate in size when the whole continuum of the local natural and anthropogenic disturbance sizes are considered; more common are the extensive clearings for agriculture or cattle ranching, whereas the most common forest disturbance is treefall gaps, at least 20 times smaller than oldfields.
6. This form of land use should be considered as an important, appropriate productive element when decisions are made about managing reserves and pursuing sustainable development.     

冀西北坝上地区的夜蛾科昆虫

系统调查研究冀西北坝上农牧交错带的鳞翅目Lepidoptera,夜蛾科Noctuidae蛾类,已知11亚科71属117种,并对其多样性做了分析。各月份蛾类组成及数量差异较大,从5月到9月蛾类多样性指数、物种丰富度和个体数基本呈上升趋势,多样性指数与均匀度(r=0.9943)、丰富度(r=0.8979)相一致。而不同月份间的蛾类相似程度差异较大。     

Linkage restoration: Interpreting fragmentation theory for the design of a rainforest linkage in the humid Wet Tropics of north-eastern Queensland

Summary Studies of forest fragmentation, particularly in the species-rich tropical zone, have contributed significantly to our understanding of its effects and impacts, and allow us to predict a cascade of flow-on effects likely to emerge in the coming decades. Practical management strategies to combat these effects, however, have not been forthcoming, despite intuitive assumptions and a growing body of scientific evidence that maintaining and restoring habitat connectivity is likely to be critical for the long-term persistence of many life forms in these fragmented landscapes. This paper reviews the potential problems involved with linkages, and examines some of the strategies adopted to overcome these issues in a linkage restoration project on the Atherton Tableland, in the Wet Tropics of north-eastern Australia. The paper concludes with the suggestion that restoration projects, such as the Donaghy's Corridor example, offer opportunities for researchers and practitioners to collaboratively observe and validate these strategies, and develop 'real world' techniques to reverse the ecological, social and economic effects of forest fragmentation.     

Community assembly after long-term fragmentation: a case study of tropical rainforest in Xishuangbanna,south-west China

Background: Tropical rainforests represent the most species-rich and at the same time the most fragmented terrestrial biome on Earth. Fragmentation of tropical rainforests is having wide-ranging consequences for the maintenance of local species diversity and community assembly patterns.

Aims: To examine floristic changes and changes in community phylogenetic structure in the forest fragment over the past five decades.

Methods: A new taxonomic diversity algorithm (within-family diversity) was developed to assess floristic changes in the forest fragment. Community phylogenetic structure was then compared before and after fragmentation.

Results: Taxonomic diversity changed greatly among families, with changes occurring randomly across the phylogeny. The forest fragment had higher phylogenetic diversity, higher mean pair-wise phylogenetic distance, but lower mean nearest-neighbour distance. The community phylogenetic structure has changed significantly from clustering to dispersion.

Conclusions: High species turnover occurred in the forest fragment. While shade-tolerant species have been lost, and ruderal and alien species have been added, overall phylogenetic diversity has increased with species being more phylogenetically distant. Competitive exclusion, which was related to the relatively drier conditions in the forest after fragmentation, led the plant community phylogenetic structure to be more dispersed.     

High plant diversity of lowland rainforest vestiges in eastern Madagascar

Based on cartography, floristic inventory and vegetation analysis in the north and south of the Eastern Domain of Madagascar we identified three original tropical rainforest types which are among the world's most biodiverse known sites for plants: the littoral forest on sand, the lowland forest on gneiss and the lowland forest on basalt. Floristic and structural comparisons were conducted on 37 plots of 50×10m. Multivariate analysis indicates that floristic composition is correlated with abiotic factors of rainfall, latitude, soil composition, and marine influence; the structure of the undergrowth is generally homogeneous and the canopy is more or less open. Many reserves must be created on gneiss, sand and basalt all along the eastern coast to preserve biodiversity from the deforestation process. On basalt, this is especially urgent because about only 10 000 ha of a very ancient forest that shelters numerous botanical novelties remain today.     

Diversity of fungi on rainforest litter in North Queensland, Australia

Ten leaves from each of 13 different tree types from two differentrainforest sites in North Queensland, Australia were examined in order toestablish the fungal diversity developing on these leaves. A total of 57microfungi were identified, most of which were mitosporic fungi. Speciesdiversity in terms of richness and evenness were compared and the Mt Lewis sitewas found to be richer as compared to the Butchers Creek site. Statisticalmeasurements of diversity indices, however, showed that the two forest siteswere of similar diversity. Thirty-six of the fungi identified occurred only onone leaf type, indicating possible host specificities or recurrences. The samplesize, however, is deemed to be insufficient, as a larger sample size may haveresulted in less of the fungi appearing to be host specific. It is recommendedthat future studies should include more leaf samples and less tree types. It isparticularly important that the same leaf species are collected within the samesite and at different sites in order to establish the effects of host on fungalcomposition.     

Roost selection by the north Queensland long-eared bat Nyctophilus bifax in littoral rainforest in the Iluka World Heritage Area,New South Wales

Abstract The aim of this study was to describe the roosts of Nyctophilus bifax in littoral rainforest in Iluka Nature Reserve on the north coast of New South Wales. Radio-telemetry was used to track 17 bats in November 1988 (lactation season) and 11 in May 1989 (mating season) to 87 roosts in 49 trees within the littoral rainforest. The bats frequently changed roosts, which were clustered within a small area. During November, lactating females moved twins between diurnal roosts and some carried twins while foraging. Twins represented a load of up to 95% of their mother's bodyweight. Bats roosted communally in foliage and tree hollows, beneath peeling bark, among epiphytes, and between strangler figs and host trees. Hollows were used more frequently when bats were lactating, while the use of foliage roosts was greater during the mating season. Roosts were concentrated in four tree species, although a wide range of other tree species was used. Roost trees used in November were taller (17m) than those used in May (8. 2 m), and reflect selection of Syzygium leuhmannii and Acmena hemilampra, both trees of the forest interior. The converse applied for selection of Cupaniopsis anacardioides, a small tree of the littoral zone, in May. These results identify the need for conserving a diversity of roosts for this species of bat.     

Diversity of geometrid moths (Lepidoptera: Geometridae) along an Afrotropical elevational rainforest transect

Geometrid moths were investigated at 26 sites on 9 elevational levels along an elevational transect at Mt. Kilimanjaro (Tanzania), stretching from the fine‐grained mosaic of small agroforest plots with combined cultivation of trees, shrubs and crops at 1650 m through mountain rainforest to heathland at 3300 m. We sampled moths manually at light between 19 : 00 and 22 : 00 in the rainy seasons of March to May and October to January in the years 2000, 2001 and 2002. Along the transect, the composition of moth communities changed from a domination by Sterrhinae and Ennominae to a dominance of Larentiinae with increasing elevation. Overall, alpha diversity was very low compared to other tropical mountain regions. Fisher's alpha showed a maximum of 30 in the agroforest mosaic at 1650 m and decreased to values around 12 in the mountain rainforest. Communities of geometrid moths within the forest belt were significantly dissimilar from communities outside the forest. The diversity patterns on Mt. Kilimanjaro can be related to the young age, island‐like position and history of the mountain. These factors have led to the formation of a homogeneous upper mountain rainforest habitat which in turn houses homogeneous moth communities with a low diversity compared to habitats at lower elevations. Here, a heterogeneous habitat mosaic allowing the intrusion of savannah species into this former forest habitat may account for an increased diversity. In the heath zone above the forest, climatic conditions are very harsh, permitting only few specialists to thrive in this ericaceous woodland. Edge effects were discernible at the forest–heathland boundary where some moth species from heathland invaded the closed forest. At the boundary between agroforest and a forest mosaic of exotic Acacia and Eucalyptus forest plantations and natural mountain forest, diversity values remained low as the dominant species Chiasmia fuscataria accounted for far higher proportions than other dominant species in any of the other habitats.     

Visitor assemblages at flowers in a tropical rainforest canopy

Abstract Canopy crane‐based studies have been carried out to quantify the sets of arthropods that visit the flowers of a suite of common species of trees, palms and vines within the Cape Tribulation study area. Those Orders that increase significantly in abundance between the budding and flowering stages of inflorescences are identified, and multivariate and univariate comparisons have been made first, among coflowering plant species and second, at different seasons for the same plant species. The analysis has been repeated for both the profile of higher arthropod taxa in the samples and for the relative abundances of families of Coleoptera: one of the Orders most frequently suggested as critical in the pollination biology of Australian rainforests. In all cases significant differences are identified among species confirming that the visitor profile is a plant species‐specific phenomenon. Profiles within plant species at different times also differed. At the ordinal level significant differences in visitor profiles associated with coflowering plants, were observed, variously, in Thysanoptera, Diptera, Lepidoptera, Coleoptera and Hymenoptera. Within the Coleoptera significant differences occurred in relative abundances of Scarabaeidae, Phalacridae, Latridiidae and Curculionidae. Seasonal differences in visitation to Syzygium gustavioides, Normanbya normanbyi and Calamus radicalis, reflected differences in Diptera, Lepidoptera, Homoptera, Thysanoptera, Hymenoptera and Araneida. Within the Coleoptera, the Elateridae and Curculionidae varied significantly between occasions. The various forms of flower/arthropod interaction that may be represented in these results are discussed, as are the implications for pollination.     

Assessing the vulnerability of an assemblage of subtropical rainforest vertebrate species to climate change in south‐east Queensland

Global climate change is a threat to ecosystems that are rich in biodiversity and endemism, such as the World Heritage‐listed subtropical rainforests of central eastern Australia. Possible effects of climate change on the biota of tropical rainforests have been studied, but subtropical rainforests have received less attention. We analysed published data for an assemblage of 38 subtropical rainforest vertebrate species in four taxonomic groups to evaluate their relative vulnerability to climate change. Focusing on endemic and/or threatened species, we considered two aspects of vulnerability: (i) resistance, defined by indicators of rarity (geographical range, habitat specificity and local abundance); and (ii) resilience, defined by indicators of a species potential to recover (reproductive output, dispersal potential and climatic niche). Our analysis indicated that frogs are most vulnerable to climate change, followed by reptiles, birds, then mammals. Many species in our assemblage are regionally endemic montane rainforest specialists with high vulnerability. Monitoring of taxa in regenerating rainforest showed that many species with high resilience traits also persisted in disturbed habitat, suggesting that they have capacity to recolonize habitats after disturbance, that is climate change‐induced events. These results will allow us to prioritize adaptation strategies for species most at risk. We conclude that to safeguard the most vulnerable amphibian, reptile and bird species against climate change, climatically stable habitats (cool refugia) that are currently without protection status need to be identified, restored and incorporated in the current reserve system. Our study provides evidence that montane subtropical rainforest deserves highest protection status as habitat for vulnerable taxa.     

Wood density predicts plant damage and vegetative recovery rates caused by cyclone disturbance in tropical rainforest tree species of North Queensland,Australia

Abstract The ability to withstand disturbance (resistance) and the ability to recover biomass following disturbance (resilience) were investigated in Australian wet tropical rainforest tree species. These two attributes are expected to be negatively correlated, because investment of biomass in structural support (conferring resistance) results in trees exhibiting high wood densities and slow growth rates, and vice versa. We examined species’ responses to disturbance caused by a severe tropical cyclone to test this hypothesized trade‐off. We assessed cyclone damage in six species in three Mabi rainforest fragments on the Atherton Tablelands. Species differed in the proportion of individuals within four damage categories (minor damage, severe branch damage, snapped, uprooted). Resistance was positively related to wood density. We found a positive correlation between the proportion of trees experiencing minor damage only and wood density, supporting the hypothesized association between resistance and mechanical strength. Among the subset of trees in which stems snapped, rates of resprouting differed between species and were highest in low wood density species and lowest in species with highest wood density. Resilience, characterized as the ability to recover biomass following disturbance and estimated as growth rate standardized for stem diameter at breast height (g day^?1 · mm^?1), was negatively related to wood density. Thus, species with low wood densities were more likely to suffer stem and branch damage owing to cyclonic winds, but also demonstrated highest resprouting and fastest responses in terms of redeveloping biomass in the 8 months following disturbance. This suggests that a species’ position along the resistance–resilience spectrum can be predicted by mean wood density, which may allow managers to predict species’ responses to future cyclones. Our findings also provide mechanistic evidence for the ‘direct regeneration’ model of post‐cyclone succession, where response is characterized by resprouting and species composition is unchanged.