Winter energy deficits and the importance of fruit versus insects in a tropical island bird population

The sedentary population of 200 to 500 silver-eyes on Heron Island, Australian Great Barrier Reef, experiences high mortality during the winter non-breeding season. The omnivorous silvereyes feed mainly on small insects gleaned from foliage, and on fruits, especially the fig Ficus opposita. Estimates of the energy content of food items reveal that small insects (2–5 mm long) provide little assimilable energy (9 J), whereas large insects (>8 mm) and bites of fig provide most assimilable energy (217 J and 181 J respectively). An analysis of the average daily intakes and expenditures (estimated by the time-budget method) for three sampling occasions showed that the rates of insect consumption (10,15 and 11 kJ day^-1) were significantly less than the energy requirements (37, 38 and 37 kJ day^-1). While many individuals may have been able to balance their energy budgets by eating figs, the calculated fruit intake rates (38, 9 and 0.5 kJ day^-1 respectively), together with high inter-individual variation in fig consumption, suggest that figs were often in short supply. The birds visited fig trees most frequently during the first 2 h after sunrise, and the feeding success rate in fig trees (approximately 20% of visits successful) during this time was significantly greater than that during the rest of the day (approximately 10% of visits successful). Alternative hypotheses for these patterns, based on protein requirements, on diurnal rhythms imposed by insect availability, or on satiation, are considered and rejected. These results indicate that the pre-breeding population size is limited by winter energy shortage, the extent of which is dependent on the size and phenology of the fig crop. Natural selection should favour individual strategies for maximization of net energy intake.     

Risk Perception Mapping: Using Ethnography to Define the Locally Affected Population for a Low-Level Radioactive Waste Storage Facility in Michigan

The concept of a "risk perception shadow" (RPS) has been suggested to describe the geocultural area in which a locally affected population perceives itself to be at risk from a proposed project. Generally such projects involve potentially dangerous substances or activities. The initial conceptualization of an RPS was developed during the social assessment of a proposed Superconducting Super Collider (SSC) in Michigan. This article describes an effort at mapping and analyzing an RPS produced by a proposal to site a low-level radioactive waste (LLRW) storage facility in Michigan. A unique sampling technique was used to define the boundary of the generally concentric RPS. Risk perception mapping (RPM) is suggested as a rapid and efficient method for defining locally affected populations for social impact studies.     

Determinants of preferred intertidal feeding habitat for Eastern Curlew: A study at two spatial scales

Abstract Broadscale habitat use by Eastern Curlews (Numenius madagascariensis) in their non‐breeding range in eastern Australia was assessed using low tide surveys on feeding grounds, where 60 skilled volunteers made repeated counts of the birds on intertidal flats, across 41% (9500 ha) of the intertidal habitat within Moreton Bay, Australia. We analysed 32 defined sections of intertidal flat, of roughly equal area (mostly 200–400 ha), which varied greatly in their curlew density (2–47 birds per 100 ha) and also in substrate and other environmental features. Sites with the least resistant substrates had densities three times those with the most resistant substrates. Of 10 environmental characteristics measured for each site, substrate resistance was the best predictor of curlew density (r² = 0.45). Characteristics that were poor predictors included distance to the nearest roost, level of human disturbance and distance to urban settlement. For a finer‐scale assessment, microhabitat use and feeding behaviour were recorded during low tide within 12 intertidal flats, which varied in size (23–97 ha), substrate, topography and other features. Across all flats, curlews strongly preferred to feed relatively close (0–50 m) to the low‐water line. They fed on a variety of substrates (including sand, sandy‐mud, mud and seagrass) in broadly similar proportions to their occurrence in the habitat. There was a statistically significant preference for sand, although its magnitude was not strong. These results indicate that curlews select habitat most strongly at a between‐flat rather than within‐flat scale.     

Damage caused by mistletoe Misodendrum punctulatum Banks Ex Dc. on architecture and radial growth of Nothofagus pumilio (Poepp. et Endl.) Krasser forests of southern Chile

Parasitic plants rely completely or partially on host plant, namely holoparasitic or hemiparasitic, respectively. The effect of parasitism on host plants is not fully known. Misodendrum punctulatum (Misodendraceae) is the most common hemiparasite species in the southernmost forests of Chile and Argentina, and it has been identified as an important sanitary problem in forestry. In this study we evaluated the M. punctulatum effect on growth rates and architecture of pure Nothofagus pumilio (Nothofagaceae) forests in southern South America (52°10′S; 71°55′W). We established three plots of 30 × 30 m, and 10 cores were extracted from diameter at breast height (d.b.h. = 1.3 m) from living trees in each plot, using increment borers. Tree rings were measured, and anova was used to compare the annual growth rate of both infected and uninfected N. pumilio. The results showed that N. pumilio trees severely infected by M. punctulatum reduce growth rates in contrast with uninfected individuals (P < 0.05). Besides, trees with high‐infection levels evidenced deterioration in its architecture, showing asymmetric and suppressed canopies, according to ad hoc numerical indexes. This study provides a starting point to understand the parasite–host relationship in the Patagonian forests of southern Chile.     

Diversification of Morpho butterflies (Lepidoptera,Nymphalidae): a re‐evaluation of morphological characters and new insight from DNA sequence data

This study compiles previously published morphological, colour and behavioural characters and includes new DNA sequence data for eight markers (one mitochondrial and seven nuclear) to re‐evaluate phylogenetic relationships and estimate times of divergence for Morpho butterflies using parsimony and Bayesian methods. We note an effect of missing data on phylogenetic inference and calculations of Partitioned Bremer Support. Morphology and DNA trees were moderately congruent, and the combined analyses of all data included elements of both sources. Both morphology and DNA support the monophyly of Morpho and the early separation of the sister pair M. marcus plus M. eugenia, but trees from different data sources are congruent mostly at derived nodes, and differ at several internal nodes. The analyses of combined data indicate that Morpho is composed of four clades each of which include one or more previously proposed subgenera. The subgenera Pessonia and Morpho were not monophyletic, and to address this issue we propose that Pessonia, syn.nov. be subsumed within Morpho. The ancestor of Morpho probably arose during the Oligocene, and most diversification seems to have occurred during the late Miocene. S‐DIVA analysis suggests eastern Andean region as the ancestral area for Morpho, and that the South American Atlantic Forest was colonized multiple times.     

Response of plant species richness and primary productivity in shrublands along a north–south gradient in Europe to seven years of experimental warming and drought: reductions in primary productivity in the heat and drought year of 2003

We used a nonintrusive field experiment carried out at six sites – Wales (UK), Denmark (DK), the Netherlands (NL), Hungary (HU), Sardinia (Italy – IT), and Catalonia (Spain – SP) – along a climatic and latitudinal gradient to examine the response of plant species richness and primary productivity to warming and drought in shrubland ecosystems. The warming treatment raised the plot daily temperature by ca. 1 °C, while the drought treatment led to a reduction in soil moisture at the peak of the growing season that ranged from 26% at the SP site to 82% in the NL site. During the 7 years the experiment lasted (1999–2005), we used the pin‐point method to measure the species composition of plant communities and plant biomass, litterfall, and shoot growth of the dominant plant species at each site. A significantly lower increase in the number of species pin‐pointed per transect was found in the drought plots at the SP site, where the plant community was still in a process of recovering from a forest fire in 1994. No changes in species richness were found at the other sites, which were at a more mature and stable state of succession and, thus less liable to recruitment of new species. The relationship between annual biomass accumulation and temperature of the growing season was positive at the coldest site and negative at the warmest site. The warming treatment tended to increase the aboveground net primary productivity (ANPP) at the northern sites. The relationship between annual biomass accumulation and soil moisture during the growing season was not significant at the wettest sites, but was positive at the driest sites. The drought treatment tended to reduce the ANPP in the NL, HU, IT, and SP sites. The responses to warming were very strongly related to the Gaussen aridity index (stronger responses the lower the aridity), whereas the responses to drought were not. Changes in the annual aboveground biomass accumulation, litterfall, and, thus, the ANPP, mirrored the interannual variation in climate conditions: the most outstanding change was a decrease in biomass accumulation and an increase in litterfall at most sites during the abnormally hot year of 2003. Species richness also tended to decrease in 2003 at all sites except the cold and wet UK site. Species‐specific responses to warming were found in shoot growth: at the SP site, Globularia alypum was not affected, while the other dominant species, Erica multiflora, grew 30% more; at the UK site, Calluna vulgaris tended to grow more in the warming plots, while Empetrum nigrum tended to grow less. Drought treatment decreased plant growth in several studied species, although there were some species such as Pinus halepensis at the SP site or C. vulgaris at the UK site that were not affected. The magnitude of responses to warming and drought thus depended greatly on the differences between sites, years, and species and these multiple plant responses may be expected to have consequences at ecosystem and community level. Decreases in biodiversity and the increase in E. multiflora growth at the SP site as a response to warming challenge the assumption that sensitivity to warming may be less well developed at more southerly latitudes; likewise, the fact that one of the studied shrublands presented negative ANPP as a response to the 2003 heat wave also challenges the hypothesis that future climate warming will lead to an enhancement of plant growth and carbon sequestration in temperate ecosystems. Extreme events may thus change the general trend of increased productivity in response to warming in the colder sites.     

Do cyclones and forest fragmentation have synergistic effects? A before–after study of rainforest vegetation structure at multiple sites

Abstract Ecological degradation within areas of remnant forest may be amplified if the effects of fragmentation interact with the effects of other environmental disturbances such as wind storms. We used before–after comparisons to assess the effects of Tropical Cyclone Larry on remnant and continuous rainforest in the Wet Tropics uplands of north‐eastern Australia. Vegetation structure was measured 3 years before the cyclone and 6 months afterwards, at eight continuous forest sites and eight remnants (6–37 ha), within 20 km of the cyclone's track. The cyclone caused extensive defoliation, felling and breakage of stems and branches (greatest among the trees >100 cm diameter which had around 50% stem loss), and increased litter and woody debris. Cyclone effects were strongly influenced by a site's spatial position (P = 0.005, 0.001 in multivariate analyses of overall damage). Maximum damage occurred 10–15 km south of the cyclone track, perhaps because of the additive effects of the west‐moving air at the southern eyewall combined with the cyclone's own rapid westward movement. Most fragments were south of the cyclone track, as a consequence of spatially selective deforestation practices, and therefore, showed greatest damage. However, once the effects of spatial position were considered, the independent differences in cyclone effects between fragments and continuous forest were lost (P = 0.23, 0.41 when north‐south distance was included as a covariate in analyses). The expected protection afforded by a continuous forest canopy seems to have disappeared in the face of extremely strong cyclonic winds and down‐draughts. Nevertheless, an interaction between fragmentation and disturbance may yet occur, during the period of post‐cyclone recovery, owing to the effects of landscape context on plant recruitment. For example, there was a higher diversity of exotic seedling germination in fragments, independent of the extent of cyclone damage.