The effects of disturbance on forest butterflies using two methods of sampling in Trinidad

The butterfly assemblages of pairs of forest habitats, differing in disturbance level, within the Victoria Mayaro reserve of South-East Trinidad, are described using walk-and-count transects and canopy and understorey fruit traps. The concurrent use of these two butterfly censusing techniques, revealed major but conflicting differences in species accumulation rates under different disturbance conditions. The disturbed evergreen habitat had the significantly highest accumulation rate from walk-and-count data but the significantly lowest from fruit trap data. This reflects the specificity of much of the fruit-feeding guild for closed canopy forest. Disturbed habitats were found to lack a distinct canopy fauna. These results are discussed in light of the intermediate disturbance hypothesis. Within a region of forest, butterflies were found to be more characteristic of a disturbance level than of a particular forest type, lending weight to the belief that butterfly faunas can be used as bioindicators of forest disturbance. Several restricted geographic range species were not adversely affected by forest disturbance, at these levels of disturbance. The butterfly censuses in this study suggest that the optimal strategy for safeguarding butterfly species richness under natural forest management regimes would be to maintain a mosaic of habitats that included areas of undisturbed primary forest and a network of other forest patches, that varied in management regime and level of disturbance.     

The effects of fragmentation and disturbance of rainforest on ground-dwelling small mammals on the Robertson Plateau, New South Wales, Australia

We surveyed ground-dwelling small mammals in twenty-four rainforest remnants which were virtual islands surrounded by farmland on a plateau on the east coast of Australia. We investigated the effect of island size, level of disturbance, isolation and microhabitat on the abundance and species richness of the mammals. The remnants ranged from 0.3 to 29 ha, resulting from fragmentation during 175 years of European occupation. Two rodent species (Rattus fuscipes[Waterhouse, 1839] and R. rattus[Linnaeus, 1758] ) and one marsupial insectivore (Antechinus stuartii Macleay, 1841) were trapped in these remnants, with an additional species (A. swainsonii[Waterhouse, 1840] ) several kilometres away in rainforest on the escarpment of the plateau. Small-mammal species richness was low, but the native species (R. fuscipes and A. stuartii) were abundant. Three-way analyses of variance demonstrated that species richness and abundance decreased significantly with decreasing remnant size and increasing disturbance, but showed no distance effect. The abundance and richness of native species responded even more significantly. The interaction between the first two effects is important. Small remnants are affected most detrimentally by increasing disturbance, large remnants are less affected, and medium sized remnants show intermediate effects. The introduced R. rattus which was least abundant in large remnants, but more abundant in distant than near remnants, was also more abundant in those with major disturbance. The single most important variable in step-wise, multiple linear regression analyses was the logarithm of remnant area not influenced by edge effects, explaining 39% of the variance in species richness, 57% for native species richness and 46% for A. stuartii abundance. Disturbance related variables additionally contributed from 12 to 30% of the variance in dependent variables, while habitat variables explained between 22 and 48% of the variance, and accounted for two thirds of the explainable variance in R. fuscipes abundance. The implications of our results for wildlife conservation on the plateau are discussed.     

Home ranges of ship rats in a small New Zealand forest as revealed by trapping and tracking

Abstract

The home ranges of 5 ship rats (Rattus r. rattus L.) in a small forest area near Palmerston North were determined for 7 months by concurrent cage-trapping and smoked paper tracking. Baited tracking platforms were over 20 times as effective as cage-trapping in obtaining location data, and home ranges revealed by tracking were on average 5 times the area of trap-revealed home ranges. All the rats were to some extent cage-trap shy. However, although cage-traps could not supply useful information on range boundaries or swift acknowledgment of boundary changes, centres of activity calculated from trap data were comparable with those from tracking data. Tracking rates of individuals were variable; it would be risky to assume that they accurately reflected intensity of use of any area over short periods or when rats may have been competing for baits. The rats had stable home ranges; 3 females had ranges predominantly exclusive to each other. The progressive removal of individuals from the study area effected the prompt expansion of adjacent ranges to include vacated areas; that is, range size was inversely related to rat density.     

Climatic limitation of the southern distribution of the common blossom bat Syconycteris australis in New South Wales

Abstract This study investigates the importance of climate as a factor influencing the southern distributional limit of the common blossom bat (Syconycteris australis). Using the climatic predictive model BIOCLIM and 73 locality records, 5. australis was predicted to have a coastal distribution in eastern Australia, where winter temperatures are relatively warm and moist conditions prevail throughout the year. The actual southern limit of S. australis, determined by mist-netting suitable habitats, was found to be at Booti-Booti (32°19'S 152°3l'E) on the mid-north coast of New South Wales. BIOCLIM predicted the southerly limit of 5. australis to be 150–200km further south of their actual limit. Booti-Booti was occupied at relatively low levels of abundance year round, while the abundance of S. australis at a site 50 km to the north was much greater, fluctuating with changes in Banksia flower numbers. Seasonal range extensions beyond Booti-Booti were not detected, despite the availability of apparently suitable habitat at Myall Lakes only 20–35 km further south. Metabolic costs of S. australis at Booti-Booti were estimated to exceed basal metabolic rate (BMR) by 4.5 times, well above the physiologically predicted limit of 2.5 times BMR. These results, together with the lack of range extensions and the close correspondence of BIOCLIM'S predicted southern limit of S. australis with their actual limit, suggest that the bat's southern distribution is limited by cold, wet winters and dry summers.     

Spatial ecology of arboreal snakes (Hoplocephalus stephensii,Elapidae) in an eastern Australian forest

Abstract Stephens' Banded Snakes (Hoplocephalus stephensii Krefft 1869) are large (to 1 m), highly arboreal elapid snakes, restricted to mesic forested areas along the eastern coast of Australia. Radiotelemetric monitoring of 16 individuals at Whian Whian State Forest in north‐eastern New South Wales over 25 months provided the first data on spatial ecology of this threatened taxon. Two major influences on movements by Stephens' Banded Snakes were identified: the distribution of large hollow‐bearing trees, and the avoidance of conspecifics. Radiotracked snakes were sedentary inside tree hollows for extended periods (mean = 8 days) during their active season, interrupted by occasional long (mean = 124 m) nocturnal movements to another shelter tree. Snakes travelled on the ground rather than within the canopy, and thus were potentially exposed to terrestrial predators. Although the home ranges of the radiotracked snakes overlapped substantially (mean = 27%), simultaneous occupancy of ‘shared’ shelter trees was less common than expected by chance. Hence, we conclude that adult Stephens' Banded Snakes generally avoid the presence of conspecifics. Snakes used from five to 30 shelter trees and home ranges of male snakes were larger than those of females (mean = 20.2 vs 5.4 ha). The large spatial scale of these movements, and limited overlap among individuals, means that a viable population of this taxon requires a large area of contiguous forest. This requirement may explain why the species has not persisted in small forest fragments.     

Survey of the terrestrial and freshwater molluscan fauna of the Pilliga forest area in northern inland New South Wales,Australia

The Pilliga forest in northern inland New South Wales, Australia, is one of the largest surviving remnants of native forest on the western slopes of the Great Dividing Range. The Pilliga landscape is a challenging environment for molluscs, dominated by dry sclerophyll forest and with limited and largely ephemeral aquatic habitats. A field survey of the area in 2006–2012 identified a surprisingly rich and relatively intact aquatic native molluscan fauna with five species of bivalves in three families and nine species of freshwater gastropods (four families), including some rare species and range extensions. The native land snail fauna comprised 18 species (six families), including an unusually rich pupillid fauna with nine species. Some range extensions are recorded and some species are narrow-range endemics. The distributions of many aquatic and terrestrial species were correlated with geology or soil type. Introduced molluscs were predominantly found in anthropogenic habitats and include two freshwater gastropods (two families) and nine terrestrial snails and slugs (eight families). This study provides insight into the original molluscan fauna of the western slopes prior to landscape-scale agricultural development and provides a benchmark for future reference.     

森林干扰对大兴安岭北部森林小流域径流情势的影响

为了解大兴安岭森林流域水文过程对森林干扰的响应,利用近配对流域方法,排除了气候变量的时空差异,对比研究了森林干扰后大兴安岭北部典型森林小流域(100 km2)洪峰径流(High flow)和枯水径流(Low flow)径流情势(Flow regimes)的变化趋势。结果表明,森林干扰对枯水径流情势影响显著,与对照流域(小北沟流域)相比,森林干扰(占流域总面积的6.74%)使老沟河流域平均枯水径流流量降低了26.58%,平均枯水径流变异系数值增加了36.77%,并且差异达到极显著水平(P0.01)。另一方面,森林植被的干扰相对增加了森林小流域的洪峰流量、历时和变异性,但与对照流域相比差异均未达到统计显著水平,说明小面积的森林植被干扰未能引起流域洪峰径流情势的显著变化。进一步对配对流域的径流浮动系数(Flashiness Index)的分析发现,森林干扰显著增加了森林小流域的径流浮动性,研究时段内干扰流域的径流浮动系数为0.078,是对照流域(0.057)的1.37倍。大兴安岭北部森林小流域的天然径流情势(Natural flow regimes)对森林干扰比较敏感,在与水文循环联系紧密的区域(例如河岸带),小范围的森林干扰便可以引起径流情势的显著变化,这在未来该地区森林和水资源的管理中需要特别注意。     

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.     

火干扰对大兴安岭北部原始林下层植物多样性的影响

在景观尺度自然火干扰历史研究的基础上,采用1个物种丰富度指数（物种数 S）、2个均匀度指数（Pielou均匀度指数Eh＇和Alatalo均匀度指数E）、3个物种多样性指数（Shannon-Wiener指数H＇,Hill多样性指数N1和N2）共6个？多样性指数,研究了长期火干扰与最近一次火干扰对大兴安岭北部原始林下木层、草本层及下层总体的植物多样性的影响.研究结果表明,本区下层植物的物种数、均匀度指数和多样性指数都以下木层显著大于草本层,因而下木层对下层植物总体生物多样性的贡献最大,也是主要影响因子.火干扰对下木层、草本层和下层总体的物种丰富度和物种多样性有显著影响,而对均匀度的影响不显著.长期的火干扰影响下,下木层、草本层和下层总体的物种数、各类均匀度指数和物种多样性指数都呈现如下格局：高频类＞中频类＞低频类,低强类＞中强类＞高强类.最近一次火干扰影响下,各个生物多样性指数都表现为一致的趋势：低强类＞中强类＞高强类;短期类＞长期类＞中期类.下层植物多样性与火干扰的关系是长期适应的结果.     

Ecological and biogeographical effects of forest disturbance on tropical butterflies of Sumba, Indonesia

ABSTRACT. Butterfly assemblages within lowland monsoon forest were compared at four sites on Sumba, Indonesia that differed in terms of protection and exhibited associated differences in levels of human disturbance. A numerical method employing principal components analysis was devised for describing forest structure at each site. The first principal component (PRIN1) grouped attributes tending towards dense forest with closely-spaced trees, a closed canopy and a poorly developed field layer, with trees that tended to be large with the point of inversion in the upper half of the trunk. The highest values for PRIN1 were recorded within protected forest, and PRIN1 values were considered to be a useful index of forest disturbance at each site. Species diversity of butterflies was highest in unprotected secondary forest, but was not affected by lower levels of disturbance. Those species occurring at highest density in secondary forest generally had wide geographical distributions, whereas those species occurring at highest density in undisturbed primary forest had restricted ranges of distribution, in most cases with a separate subspecies on Sumba. Overall, an index of biogeographical distinctiveness decreased with increasing disturbance, and this supports the hypothesis that the most characteristic species of undisturbed climax forest have the smallest geographical ranges of distribution. Species abundance data for butterflies fitted a log-normal distribution at all but the most disturbed site. These results indicate that the pattern of proportional abundance of tropical butterfly species may be used as an ‘instantaneous’ indicator of forest disturbance, and that changes in the structure of tropical forests in S.E. Asia resulting from human disturbance, even within partially-protected forest, may result in the presence of butterfly assemblages of higher species diversity but of lower biogeographical distinctiveness, and therefore of lower value in terms of the conservation of global biodiversity.     

The shelled gastropods of the Solitary Islands Marine Park,northern New South Wales,Australia

ABSTRACT

Away from the major population centres, the biodiversity of Australia's shallow coastal marine waters is poorly known. The Tweed-Moreton Bioregion, covering northern New South Wales and south-east Queensland, is both a focus of marine conservation (with three marine parks), and research efforts to predict the effects of climate change through species range extensions and shifts in community composition. Here we provide the first comprehensive list of shallow-water (<30?m) shelled, gastropod macro-molluscs (>5?mm) from the Solitary Islands Marine Park, compiled from a range of sources, including field collections over a 30-year period to 2017. The Cypraeidae (50 spp.), Muricidae (47 spp.) and Conidae (32 spp.) were the most speciose families, accounting for 26% of the total inventory of 500 species from 77 families. A total of 143 species are recorded at their southern limit of distribution on Australia's east coast, most being rare, tropically affiliated taxa found at offshore island sites that receive more frequent contact with the southward-flowing East Australian Current. The inventory confirms the high biodiversity of the Solitary Islands region and the importance of ongoing conservation management.     

Dissolved and particulate organic carbon in two wetlands in southwestern New South Wales,Australia

Concentrations of dissolved (DOC) and particulate organic carbon (POC) in two billabong wetlands (Murrumbidgil Swamp and Lake Merrimajeel) in inland temperate Australia were positively correlated with leaf fall from river red gums Eucalyptus camaldulensis (DOC and POC in Murrumbidgil Swamp), phytoplankton productivity (DOC in Murrumbidgil Swamp, DOC and POC in Lake Merrimajeel), and with biomass of aquatic macrophytes (DOC in the two wetlands). DOC correlated with water level at both sites. Mean concentrations of DOC (Murrumbidgil Swamp, 36.0 gm^-3; Lake Merrinmajeel, 27.5 g m^-3) and POC (15.0 g m^-3; 15.5 g m^-3) were high compared with other water bodies worldwide, although average for wetlands. The relatively high concentrations of DOC and POC in the study wetlands appear to be the result of their high rates of plant production, and input of leaves from river red gums.     

Home range, denning behaviour and microhabitat use of the carnivorous marsupial Dasyurus maculatus in eastern Australia

Radio-tracking of spotted-tailed quolls Dasyurus maculatus (Marsupialia: Dasyuridae) in the forested ranges of north-eastern New South Wales revealed that home ranges were extensive, with males occupying large, overlapping ranges [minimum convex polygon (MCP) up to 757 ha] and females occupying smaller, non-overlapping territories (MCP up to 175 ha). Quolls were partly arboreal, although most activity occurred on the ground or on fallen logs. Hollow logs were most frequently used as dens, but rock crevices, burrows, tree hollows and artificial structures were also used. Individual quolls were located in up to nine different dens and, with the exception of maternal dens, rarely sheltered in the same location on successive days. The large home ranges of the spotted-tailed quoll and the non-overlapping nature of female ranges necessitate very large areas of habitat to support viable populations. Fallen timber, used extensively for shelter and in travelling, may serve to enhance the quality of habitat for the species, and should be retained by forest and wildlife managers.     

Antibodies to the Ross River virus in captive marsupials in urban areas of eastern New South Wales, Australia

Serum samples collected from 224 tammar wallabies (Macropus eugenii) in two captive populations in urban areas in eastern New South Wales Australia, between December 1999 and May 2004, were tested for antibodies to Ross River virus (RRV). In one population in northwest Sydney, 21 animals (11%) tested positive, and in another population in Newcastle, New South Wales, thirteen (33%) of the animals were positive. Antibodies were detected in four of 11 wallaroos (Macropus robustus) (36%) but not in parma wallabies (Macropus parma) (n=5), koalas (Phascolarctos cinereus) (n=12) and southern hairy-nosed wombats (Lasiorhinus latifrons) (n=2) from the Sydney area. These data support the possible role of marsupials as urban amplifying hosts for RRV.     

Impact of logging on the richness and diversity of forest butterflies in a tropical dry forest in Thailand

Studies on the impact of logging on tropical forest butterflies have been almost exclusively conducted in moist forest habitats. This study considers the impacts of small-scale logging on butterfly communities at three sites of varying disturbance intensity in a tropical dry forest in western Thailand. Butterfly species richness was similar at all sites, but the abundance of butterflies and diversity of the butterfly community decreased with increased logging disturbance. The recorded decrease in diversity at the relatively large sampling scale used lends further support to the hypothesis that disturbance effects are scale dependent. Species abundance data for butterflies fitted a log-normal distribution at all sites, but also a log-series distribution at the two disturbed sites. These analyses suggest a more complex butterfly community at the undisturbed site, but also that log-series and log-normal distributions may not to be sufficiently sensitive to be useful indicators of community changes following logging. Community ordination separates both the butterfly species and transect samples into three distinct regions corresponding to the three study locations. Ordination axes are correlated with tree density, understorey cover and understorey plant richness. Species with the smallest geographic ranges tend to be the least abundant and occurred most frequently in the undisturbed site. The observed diverging responses to disturbance among butterfly families diminishes the value of butterfly communities as biodiversity indicators, and forest managers should perhaps focus on restricted range species or of groups of recognized sensitive species for this purpose.     

Habitat use, home range and foraging preferences of the coati Nasua nasua in a pluvial tropical Atlantic forest area

Coatis (genus Nasua ) occupy a large range of forested habitats. The aim of this study was to describe the use of habitat by Nasua nasua in a continuous pluvial tropical Atlantic forest area, the Carlos Botelho State Park (CBSP) in south-eastern Brazil. Use of space by N. nasua in the CBSP was characterized by an average home range area for one group of 445 ha by the minimum convex polygon method and 544 ha by the fixed kernel method, which was used across 2 months; the use of trees for foraging and travelling was superior to that reported for N. nasua and Nasua narica until now, being higher in the drier season. The home range of three coati groups shifted during the 3 years of this study; the home range of one habituated group changed by 91%. The proportion of ground foraging increased with the higher availability of soil invertebrates during the rainy season, but cannot be explained solely on the basis of resource availability.     

Effects of disturbance and size structure on the regeneration process in a sub-boreal coniferous forest,northern Japan

The stand structure and disturbance history in a sub-boreal coniferous forest dominated byPicea jezoensis, Picea glehnii andAbies sachalinensis were investigated in four study plots set up in Taisetsuzan National Park, Japan. The effect of stand characteristics on the growth and mortality rates of understory trees was examined. Although all the stands showed inverse J-shape d.b.h. (diameter at breast height) distributions, the age structure and disturbance history differed amongst the stands. The stands with wide d.b.h. distribution (i.e. large CV and skewness) were more uneven-aged than those with narrow d.b.h. distribution (i.e. small CV and skewness). The disturbance-return interval based on the model of Hett and Loucks was 31 to 65 years. The gap ratio in the canopy was also different among the stands. These suggest that the variations in stand structure represent different occurrences of natural disturbances. Furthermore, the structural features such as size structure, canopy gap ratio and density of canopy trees also affected the growth dynamics of understory trees (≥2 m in height and <10 cm in diameter at breast height). The growth and mortality rates of understory trees changed with the canopy gap ratio and canopy tree density. The understory trees of stands with wide canopy d.b.h. distribution had higher growth and canopy recruitment rates than those of stands with narrow canopy d.b.h. distribution, contributing to the maintenance of continuous stand stratification. The understory trees of stands with narrow canopy d.b.h. distribution showed lower growth and higher mortality rates than those of stands with narrow canopy d.b.h. distribution, leading to the formation of a single-canopy structure. It is suggested that natural disturbance governs the regeneration process in the future by affecting the growth and mortality patterns of understory trees through the stand structure (size and age structure, canopy tree density, canopy gap ratio).