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Impact of reserve area on reproduction of a moth‐pollinated <i>Stackhousia</i> Sm. (Celastraceae) species in a fragmented landscape

AbstractLandscape disturbance frequently results in reduced pollination and reproduction of animal‐pollinated plants. However, few studies globally, and no studies in Australia, have focused on the impact(s) on plants with nocturnal moth pollinators. This study measured natural levels of reproduction of the common, nocturnally moth‐pollinated plant Stackhousia aspericocca Schuch. ssp. Cylindrical inflorescence (W.R.Barker 1418) (Celastraceae) across a range of reserves of varying sizes within a fragmented landscape of southern Australia. We hypothesized that plant reproduction would show a positive relationship with reserve area. Nocturnal pollinator surveys confirmed that night‐flying settling moths of the families Geometridae and Noctuidae visited flowers of S. aspericocca ssp. Cylindrical inflorescence in the study region, and 8 out of 16 captured, flower‐visiting moths carried more than 100 pollen grains of the study species (overall mean ± SD: 616.69 ± 1155.70). Two individuals of the common geometrid moth Oenochroma vinaria each carried over 3000 pollen grains. Thus, visiting moths may remove and carry large amounts of pollen. In contrast to our initial hypothesis, however, plant reproduction, measured as proportional fruit‐set and mean seed number per fruit, showed no relation to reserve area across two consecutive years, and mean levels of plant reproduction were spatially similar throughout the fragmented landscape of the study region. It is hypothesized that the reproductive resilience of S. aspericocca ssp. Cylindrical inflorescence in the study region is due to effective pollination by common, night‐flying moths, which may utilize both the reserves and their surrounding matrix to complete their life cycle(s).

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Ecosystem stability of temperate grasslands in response to variability of hydrological conditions

AbstractThe relationship between biodiversity and the stability of ecosystem functioning over time has been widely studied. The current global context has refloated this topic for biodiversity's role in buffering the effects of different disturbances. In general, the results of these studies show that ecosystem functioning is more stable over time in more diverse systems. However, these results are derived from empirical research on small‐scale studies, where species and disturbances conditions are manipulated. In this work, we used climate and floristic information data obtained from surveys over an extended period on Flooding Pampa grasslands (Argentina) with a remotely sensed indicator of the stability of net primary productivity at a regional scale over a broad temporal range to evaluate the relationship between species diversity and the stability of ecosystem functioning under different water conditions. We found a close correlation between Normalized Difference Vegetation Index responses of natural grasslands and climate variability in the study area. Besides, grasslands with higher species richness and diversity showed greater stability in ecosystem functioning at different water conditions. The results obtained could be relevant in natural resource management for the close relationship between diversity–stability in a local and regional productive context characterized by a simplified landscape of space and time.

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The ecology and morphology of Australia's desert turtle (<i>Emydura macquarii emmotti</i>)

AbstractCooper Creek is one of Australia's largest unregulated river systems and one of the world's most variable large river systems. It is a dynamic environment that oscillates between booms and busts; yet, many species thrive in it. One of these species, the Cooper Creek turtle (Emydura macquarii emmotti) has received little attention, despite being one of Australia's largest freshwater turtles and living further inland than any other Australian turtle. We conducted surveys for E. m. emmotti in 2001–2004, 2019, and 2022, focussing predominantly on the Waterloo waterhole. Waterloo had a large population of E. m. emmotti (508 estimated individuals; 95% CI = 447–596) with an estimated density of 64.8 turtles/ha (95% CI = 57.0–76.2) and estimate biomass of 74.4 kg/ha (95% CI = 57.6–100.3 kg/ha). Juveniles were highly abundant in all years, representing up to 63.6% of captured individuals. It was slightly (but not significantly) male‐biased in 2001–2004 and significantly female‐biased in 2019. All sizes and sexes used the floodplain during a flooding event in 2022, but more males than females were captured on the floodplain, and there was evidence of male‐biased dispersal across the years. Compared to Murray River turtles (Emydura macquarii macquarii), E. m. emmotti exhibited megacephaly across all ages and sexes, with particularly pronounced megacephaly in adult females. Algae were present on many individuals (including on the skin and plastron) but was relatively more abundant on juveniles. Leeches were not detected on any of the 66 turtles that were examined for them. The following injuries/malformations were noted: missing or injured limbs (3.2%), missing or injured eyes (1.3%), damaged shells (8.0%), scute/shell anomalies and malformations (10.6%), and marginal scute seams extending into the costals (67.4% of adults, 1.2% of juveniles). This paper presents some of the first work on this unusual turtle and makes recommendations for future research.

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What happens when fire is too early? Observations of fire‐stimulated fruit opening releasing underdeveloped seeds for an endemic Cerrado shrub

AbstractThe relation of fire with the reproductive process of species from tropical grasslands and savannas has long been investigated. Post‐fire flowering is well documented in the Cerrado, but fire‐mediated fruit opening and seed dispersal has rarely been described, with very few historical records being known. Even less is known about the effects of different fire seasons on species reproduction. Here, we describe the fire‐stimulated fruit opening of Jacaranda ulei, an endemic Cerrado shrub with medical importance to traditional communities. We show that fruits opened within 2 weeks after an early dry season fire, but there were almost no viable seeds as fruits were still immature when burned. When put together with the known records for other species, dry dehiscent fruits and anemochory arise as common traits that favour fire‐mediated fruit opening. As these are common attributes in the Cerrado, it is possible that several other species also have fire‐stimulated seed dispersal but remain vastly unnoticed and underreported in the literature. Additionally, the peak reproductive effort of these species coincides with the period of prescribed burns of the Integrated Fire Management Program and, consequently, several species could also have their reproductive cycle interrupted to disperse immature seeds. We hope our note encourages further studies on the fire‐mediated fruit opening and seed dispersal of Cerrado species, particularly in relation to fire season and seed quality.

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Bat boxes in urban bushland are associated with inflated activity of an urban generalist bat, but not an altered community

AbstractBat boxes are often installed as substitute habitats to offset the loss of large, hollow‐bearing trees. However, emerging evidence suggests that they are failing to achieve intended conservation outcomes as they only support generalist species. Despite these concerns, the effect of bat boxes on the dynamics of bat communities remains understudied. We assessed the bat community in reserves where bat boxes had been installed in comparison with reserves where they had not using ultrasonic surveys in 16 small bushland reserves throughout Sydney, Australia. Reserves containing bat boxes and those without had comparable species diversity and composition; however, the activity of the dominant species, Gould's wattled bat (Chalinolobus gouldii), was significantly higher at sites with bat boxes. Species that commonly forage in open vegetation, including C. gouldii, were significantly positively associated with sites that had bat boxes. Occupation of boxes by bats was not recorded in the study due to limited information on their locations, so further research is required to understand the direct effects of boxes and the bats that occupy them on the bat community. If bat boxes continue to be recommended as a biodiversity offset, a greater understanding of the potential impact they have on altered competitive relationships and community dynamics is essential.

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Quantifying the distribution and morphological variation of the beetles <i>Homocopris achamas</i> and <i>Uroxys coarctatus</i> in Andean ecosystems of Colombia

AbstractInsects that inhabit high‐altitude ecosystems are an ecologically specialized group whose distribution is restricted by the presence of biogeographical barriers. These biogeographical constraints are thought to mould the shape of some insect structures because of environmental pressures that may produce better adaptations in extreme environments. We evaluated the potential distribution of Homocopris achamas and Uroxys coarctatus in two life regions (the Andean region and the Páramo region) found in the Andes of Colombia, and we determined if there were differences in their morphology along an elevational gradient. To determine the potential distribution of the species, we obtained geographical data through the systematic search of databases and entomological collections that we modelled under the maximum entropy model. We then evaluated the morphological variations by measuring geometric structures such as the clypeus (MC), the eye (ME) and the area of the anterior tibia (TA). We found that both species along the entire gradient exhibited the following characteristics: H. achamas was dominant in the Páramo region and showed two population nuclei separated by a wide biogeographic barrier, while U. coarctatus was more dominant in the Andean region and was distributed only in the northern Andes. Both were always linked to ecosystems with open vegetation that was both natural or intervened. H. achamas did not show changes in the shape of the structures while U. coarctatus showed differences in MC and ME. We suggested that livestock activity could act as an engine for breaking down biogeographical barriers allowing the distribution of a species to expand, and with this distributional expansion changes in the morphological structures of some species linked to their phenotypic plasticity could be promoted.

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Acoustic communities in an environmental gradient from native to urban areas in Central Brazil

AbstractAs urban areas expand due to increasing human populations, natural habitats are diminishing in quantity and quality. We conducted a study to examine the response of diurnal acoustic communities along a gradient of environments, ranging from native to dense urban areas. We hypothesized that acoustic indices would decline with urbanization, transitioning from natural and rural areas to urban environments. We conducted the research in and around Brasília, Central Brazil. We deployed 24 digital recorders in native, rural, low‐density and high‐density urban areas. We employed five commonly used acoustic indices (ADI, ACI, NDSI, H and BI) to characterize the acoustic communities and represent the existing biodiversity numerically. We initially compared the index values across different land use types using a non‐parametric rank sum test. Subsequently, we selected eight landscape metrics and performed a principal component analysis to summarize the surrounding matrix at each sampling point. We then employed generalized linear models to determine if the acoustic indices exhibited the anticipated variations. The results indicated significant variations in all indices among the different land use types, indicating their responsiveness to distinct acoustic communities and environmental characteristics. ADI, H and NDSI exhibited declining values from native to urban areas, while ACI and BI displayed the opposite trend. These findings underscore the influence of landscape structure on acoustic indices. Consequently, we concluded that adopting appropriate landscape planning, mainly through integrating natural and urban areas, could help preserve biodiversity in tropical urban regions.

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