Austral Ecology最新文献

Males of the endangered northern quoll (Dasyurus hallucatus) are facultatively semelparous, often dying following their first breeding season. This is often driven by high breeding costs: males travel and mate extensively in breeding season, resulting in reduced body condition. Annual post-breeding survival rates for male northern quolls have been recorded between 0% and 12.5% across their range in northern Australia. We highlight an observed 50% survival rate of male northern quolls (3 of 6) living into their second year in a Pilbara mining landscape. High male survival here may be attributed to above average rainfall in the landscape and reduced breeding opportunities, due to low female abundance—likely driven by large amounts of unfavourable mining land. This likely led to lower hormonal stress associated with breeding for males, as well as increased resource availability. Given northern quoll population persistence is highly dependent on breeding success, high survival of male northern quolls may inadvertently stabilize populations if they can breed again in a second year, though this is yet to be observed in the Pilbara region. Nevertheless, semelparity of male northern quolls likely varies with environmental and demographic factors, demonstrating that northern quoll populations may be resilient to disturbance in an unpredictable semi-arid environment.

In the forest-steppe transition of Patagonia from Argentina, the intense physical variability promotes the occurrence of contrasting vegetation units, among which is the saxicolous meadow developed on rock outcrops. In temperate and tropical regions, these geoforms of highly variable climate and topography, and poor soil development play an ecological and evolutionary role disproportionate to their reduced area. In Aguas Frías (38°46′S, 70°54′W), the range, diversity, density and adaptation of vascular plant species growing in the saxicolous meadow were compared to those of the surrounding steppe, forest and hygrophilous meadow. We hypothesize that rock outcrops exhibit a compositionally and functionally divergent, cold-adapted flora of a previously more widespread distribution, allowing them to be categorized as refugia for species whose range retreated during the current interglacial. In comparison to the other units, the saxicolous meadow exhibited a small area, low plant cover, high total, native and rare species richness, high density and diversity of species, high richness of unique families and species and an exclusive presence of (rock) ferns. It also presented a high richness of endemic species with more extreme latitudinal and altitudinal distribution, particularly >46° S and >3000 m a.s.l. The similarity of species between the saxicolous meadow and the other units was low. Chamaephytes and nanophanerophytes were dominants, hemicryptophytes and geophytes were infrequent and mesophanerophytes and therophytes were absent. Equivalent results in terms of area of rock outcrops, and origin, strategy, composition, diversity and range of species were found in different regions. The biological and physical attributes would allow these outcrops to be characterized as reduced habitats of high diversity which could be acting as refugia for cold-adapted plants. Conservation actions must prevent and mitigate the effects of fire, biological invasion and cattle grazing that represent the current threats to this ecosystem.

High Andean lizards in the Andes face numerous challenges in high-altitude environments characterized by significant temperature, spatial and temporal variations. These factors greatly influence their thermal characteristics and adaptive strategies for coping with temperature fluctuations. This study aims were to investigate the thermal biology of high mountain lizards (>2000 m) inhabiting the Andes Mountain range, using information from existing literature, and to identify the potential impacts of the original climate change scenarios developed in this study. Within the Andes, high-altitude species are primarily found in families like Liolaemidae, Gymnophthalmidae, Tropiduridae, Anolidae and Leiourisauridae. Notably, we found in the literature that the higher body temperatures and maximum critical temperatures in southern species compared to those closer to the tropics. Typically, diurnal and seasonal temperature variations have a significant impact on the body temperature of these high-altitude lizards, but their adaptive behaviours and physiological mechanisms enhance their resistance to extreme temperatures. Populations situated below the equator often exhibit higher body temperatures and maximum critical temperatures, largely due to their exposure to higher ambient temperatures during summer. With all global warming scenarios indicating temperature increases in latitudinal regions, tropical high-altitude lizards, historically less thermally adaptable, may be particularly susceptible to these temperature rises. It is crucial to consider that additional factors, such as species activity patterns, thermal resource availability and diminishing suitable thermal habitats, will also play a pivotal role in shaping the future of these lizard species, making the situation even more complex and challenging.

We analysed nearly 31 years (1991–2022) of tree population dynamics in 108 permanent plots each 0.04 ha of the Lilyvlei Nature Reserve, a section of the Knysna Forest in South Africa which has not historically been disturbed by harvesting. The Knysna Forest is the only large piece of forest in South Africa and is marginal for tall forest, having low mean annual rainfall of only about 1000 mm and occurs on nutrient poor soils. In contrast to many studies of other forests globally, we found almost no change in overall biomass. Even at the scale of our small plots and on 10–30 year time scales, there has been little change. The forest has very low recruitment and mortality rates and thus low growth rates. Climatic changes too were minimal over this 30-year period. The proportion of stems that died per size class was concentrated in the larger size-classes per species, even for shorter species. This suggests that senescence rather than external disturbances determines the low mortality and thus the low dynamism and the high biomass (approx. 600 Mg ha⁻¹AGB or 41 m² ha⁻¹ basal area) of the forest. Mortality of some species exceeded conspecific recruitment, a trend accompanied by non-significant declines in biomass. However, these trends are not significant. In conclusion, neither composition nor biomass has changed significantly in these forests over a period of 30 years. This suggests that not all Southern Hemisphere forests are in a state of decline.

Fruit and seed morphometry was studied across 1070 plant species belonging to 140 families from 27 contrasting plant communities. The main objectives were to identify allometric relationships and describe the frequency distributions of the weights and sizes of fruits and seeds across plant species, regardless of any qualitative attribute or community type. The frequency distributions of 12 morphometric variables were then determined. Pearson correlations were used to describe associations between quantitative attributes and estimate the slopes of the lines (allometric coefficients) obtained. In general, small fruits and seeds (<1 cm) prevailed in the sample examined. The frequency distributions of the weight and size parameters of the fruits and seeds were bell-shaped, with the exception of the number of seeds per fruit, which was skewed to the right. The highest allometric coefficients were found between the dry weights and sizes of the fruits and seeds, suggesting that these traits are mutually supporting. The cost of seed packaging per fruit, or the pericarp/seed ratio, tended to decrease with increasing investment in progeny, and the number of seeds per fruit decreased with an increase in seed weight. The significant associations between the fruit shape indexes and the morphometric attributes show that the shape of fruits is related to their size and weight. The highest allometric coefficients were found between the dry weights and sizes of the fruits and seeds. Fruit and seed size can predict their biomass and vice versa. There is a close relationship between fruit biomass values and their components (seeds and pericarp). Most species invest more biomass in pericarp (protection and dispersal) compared with the investment in progeny (seed per fruit). The sample examined could be influenced taxonomically along with selective pressures that favour the reproductive economy of the species and suggest that morphometric traits have evolved in coordination.

Understanding what drives the evolution of nectar-robbing strategies is key for gaining insight into the functioning of pollination networks. However, nectar robbing is often an anecdotal behaviour, difficult to quantify and record through field observations, especially in hummingbirds, limiting our understanding of how ecological networks change across communities. Here, we report new records of nectar robbing by Peru's endemic Black Metaltail (Metallura phoebe) in a high-elevation forest at ca. 4000 m a.s.l. and how this species uses either legitimate pollination feeding or nectar robbing in relation to corolla lengths. Furthermore, by analysing 452 citizen science records of photographic observations, we found that 36% of the photographs depicting a foraging event in this species were actually nectar-robbing events. After identifying the plant species in all photographs involving foraging events, we describe how nectar robbing conducted by this hummingbird species is strongly associated with flowers that have longer corollas. We propose that the hummingbird-flower interactions in harsh high-altitude environments, where resources and competition vary markedly across seasons, can offer insight into the ecological drivers of nectar-robbing behaviour in hummingbirds.

Coeli Gomes de Lucena Costa, A. & Campos Gomides, S. (2024) Disentangling drivers of vertebrate roadkill in a protected area in the Amazon rainforest. Austral Ecology, 49, e13571. Available from: https://doi.org/10.1111/aec.13571

In the ‘Data Analysis’ section, the sentence ‘on the railroad, as monitoring took place fortnightly, the number of inspections was equal to 48.’ has been corrected to ‘on the railroad, as monitoring took place fortnightly, the number of inspections was equal to 144.’

We apologize for this error.

Bat-pollinated plants feature open flowers, facilitating easy access to their abundant nectar for various animal groups. The Caatinga, a Brazilian Seasonally Tropical Dry Forest, stands out globally as a hotspot for bat-pollinated plants. This study presents the first documentation of the opossum Didelphis albiventris (Marsupialia) engaging in the consumption of nectar on flowers of Hymenaea cangaceira (Fabaceae), a bat-pollinated tree species within the Caatinga. The observation spanned five nights and occurred unexpectedly during an experiment involving bagged flowers to assess nectar dynamics. Initially, torn bags were discovered containing flowers, which nectar had been consumed. Subsequent nights revealed the opossum actively exploring bagged flowers, likely guided by the fragrant nectar of H. cangaceira, and unmanipulated flowers located in the canopy's upper reaches. Given the opossum's contact with reproductive structures during these visits, it emerges as a potential pollinator. Following this observation, a comprehensive literature review on Didelphis interactions with other plants was conducted, leading to the construction of a meta network. This network unequivocally illustrates that the majority of plants visited by Didelphis indeed have bats as their primary pollinators. Owing to the nocturnal, arboreal and stealthy nature of opossums, documenting their interactions with flowers proves highly challenging. Consequently, our record highlights significant knowledge gaps in comprehending the interplay between opossums and chiropterophilous flowers. These gaps include the under-sampling of this process in the Caatinga, the role of olfactory signalling and the broader consequences of this unique interaction.

Among dung beetles, ‘sit and wait’ comprise a common strategy, in which individuals perch on leaves. The goal of this study was to assess the spatial dynamics of dung beetle perching in a region of the Amazon. We analysed the intra- and interspecific relationships between individual body size, leaf area, leaf shape, and the height at which beetles perched. When analysing intraspecifically, the larger individuals of Canthidium bicolor perched higher than the small ones. When considering the three most abundant species, the smallest species (C. bicolor) perches lower, the intermediate species (Canthidium deyrollei) perches higher, and the largest species (Canthon triangularis) perches at an intermediate height. The leaf area also explained the vertical distribution, both when considering all individuals and intraspecific for C. bicolor, where there is a positive relationship between leaf area and perch height. Our results suggest that intra- and interspecific perching dynamics also depend on species life history, which could be further analysed under functional group approaches.

In 2023, Forster et al. published an article on the effectiveness of social media in conservation messaging for the Threatened Species Commissioner's Threatened Species Bake Off. The research of species represented in cakes revealed persistent biases favouring charismatic mammals and birds over less charismatic taxa like plants. The authors recommended future iterations of the Bake Off focus on less popular threatened species to address these biases, whilst highlighting the utility of the data available on social media platforms. In this follow-up article, we examine the impact of the theme choice by the Office of the Threatened Species Commissioner which was directly influenced by the previous publication's findings. The 2023 theme, ‘Loving the unlovely and getting to know the unknown’, aimed to increase participation by focusing on plants and the under-represented. Results indicated a notable increase in representation of these groups compared with previous years, suggesting theme selection significantly influences public engagement. The study emphasizes the potential of social media platforms in raising awareness and fostering pro-conservation behaviours, highlighting their role in shaping public perceptions and supporting policy changes for species conservation, and lists recommendations for future iterations of such campaigns.