Austral Ecology最新文献

Loss of trees in production landscapes has been widely documented and frequently attributed to both natural (climate) and human (e.g., introduced herbivores and land modifications) drivers. Effective interventions are required to restore landscapes and facilitate natural regeneration. Here, we used a natural experiment to test for the effectiveness of interventions designed to protect seedlings and saplings from herbivore damage and thus facilitate forest and woodland regeneration. We conducted a systematic survey of 283 young trees in a 47-ha site within a Eucalyptus viminalis grassy woodland contained in a conservation reserve of a grazing property in Lutruwita, Tasmania. Interventions included physical barriers to protect young trees, including caging (78 young trees), erecting stock exclosures (44) around groups, and the novel use of wool offcuts (‘dags’), as a sensory deterrent, placed around the bases (41). All three interventions reduced browsing damage compared to controls. Browsing damage was predominantly attributed to Fallow deer (Dama dama L.), based on the type of damage recorded and the relatively high proportion of deer scats across the study site. As a measure of effectiveness, young tree height was greater under any of the interventions than for unprotected trees (ranging from 27%–68% taller). Our results indicate that human intervention is required to increase the proportion of naturally regenerating trees reaching maturity, and that wool dags, as a by-product of the grazing industry, can be an effective barrier to reduce damage from feral deer as a cheaper alternative to caging.

Loss of trees in production landscapes has been widely documented and frequently attributed to both natural (climate) and human (e.g., introduced herbivores and land modifications) drivers. Effective interventions are required to restore landscapes and facilitate natural regeneration. Here, we used a natural experiment to test for the effectiveness of interventions designed to protect seedlings and saplings from herbivore damage and thus facilitate forest and woodland regeneration. We conducted a systematic survey of 283 young trees in a 47-ha site within a Eucalyptus viminalis grassy woodland contained in a conservation reserve of a grazing property in Lutruwita, Tasmania. Interventions included physical barriers to protect young trees, including caging (78 young trees), erecting stock exclosures (44) around groups, and the novel use of wool offcuts (‘dags’), as a sensory deterrent, placed around the bases (41). All three interventions reduced browsing damage compared to controls. Browsing damage was predominantly attributed to Fallow deer (Dama dama L.), based on the type of damage recorded and the relatively high proportion of deer scats across the study site. As a measure of effectiveness, young tree height was greater under any of the interventions than for unprotected trees (ranging from 27%–68% taller). Our results indicate that human intervention is required to increase the proportion of naturally regenerating trees reaching maturity, and that wool dags, as a by-product of the grazing industry, can be an effective barrier to reduce damage from feral deer as a cheaper alternative to caging.

Urbanisation is a powerful environmental force, negatively impacting the few organisms that persist in urban areas. Fluctuating asymmetry (FA), a recognised bioindicator of ontogenetic and environmental stress, may reflect such impacts, though its role in assessing urban intensification remains unclear. We investigated the relationship between urbanisation intensity and FA in birds, analysing 10 locally abundant species in Brasília city, Brazil. Our hypothesis posited that birds in more urbanised areas would exhibit higher FA. We measured bird tarsus and wing to assess asymmetry and also examined whether FA differed between traits. Neither wing nor tarsus FA increased with urban intensity. However, tarsus FA was consistently higher than wing FA. Notably, our FA values for both traits are comparable to or, in the case of tarsus, exceed those reported for birds in fragmented forests. These findings suggest that urbanisation (even at lower intensities) may impose stronger genetic and/or environmental stress on developmental stability than previously recognised.

Urbanisation is a powerful environmental force, negatively impacting the few organisms that persist in urban areas. Fluctuating asymmetry (FA), a recognised bioindicator of ontogenetic and environmental stress, may reflect such impacts, though its role in assessing urban intensification remains unclear. We investigated the relationship between urbanisation intensity and FA in birds, analysing 10 locally abundant species in Brasília city, Brazil. Our hypothesis posited that birds in more urbanised areas would exhibit higher FA. We measured bird tarsus and wing to assess asymmetry and also examined whether FA differed between traits. Neither wing nor tarsus FA increased with urban intensity. However, tarsus FA was consistently higher than wing FA. Notably, our FA values for both traits are comparable to or, in the case of tarsus, exceed those reported for birds in fragmented forests. These findings suggest that urbanisation (even at lower intensities) may impose stronger genetic and/or environmental stress on developmental stability than previously recognised.

Drosera L. (Droseraceae) is a diverse genus of carnivorous plants that is cosmopolitan in distribution, with Australia its centre of diversity (ca. 160 species in Australia). Collectively known as sundews, their leaves are covered with mobile sticky hairs (“tentacles”) that serve as active flypaper-type traps that catch small invertebrates. This prey is then digested with enzymes and absorbed as nutrition for the plant. Not all invertebrates fall prey to sundews, with sundew bug species of the genus Setocoris China & Carvalho, 1951 (Miridae) avoiding capture and stealing the plant's prey, in an unusual case of kleptobiosis. This specialised interaction suggests that the bug and host plant are highly co-adapted, although most aspects of the natural history of this interaction are poorly understood. In this study, field observations made over the course of 3 months show that the undescribed species Setocoris n.sp_BINA are first present on their host plants (Drosera binata Labill. and Drosera peltata Thunb.) when plants are sticky and catching prey. Sundew bugs are observed first on D. peltata and then D. binata, corresponding to the differing phenologies of each host plant species. These observations generated the following hypotheses for future testing: (1) S. n.sp_BINA move between host species to prioritise prey availability, and (2) S. n.sp_BINA eclosion is triggered by the same moisture and/or temperature cues as their hosts so that hatching coincides with prey availability.

Drosera L. (Droseraceae) is a diverse genus of carnivorous plants that is cosmopolitan in distribution, with Australia its centre of diversity (ca. 160 species in Australia). Collectively known as sundews, their leaves are covered with mobile sticky hairs (“tentacles”) that serve as active flypaper-type traps that catch small invertebrates. This prey is then digested with enzymes and absorbed as nutrition for the plant. Not all invertebrates fall prey to sundews, with sundew bug species of the genus Setocoris China & Carvalho, 1951 (Miridae) avoiding capture and stealing the plant's prey, in an unusual case of kleptobiosis. This specialised interaction suggests that the bug and host plant are highly co-adapted, although most aspects of the natural history of this interaction are poorly understood. In this study, field observations made over the course of 3 months show that the undescribed species Setocoris n.sp_BINA are first present on their host plants (Drosera binata Labill. and Drosera peltata Thunb.) when plants are sticky and catching prey. Sundew bugs are observed first on D. peltata and then D. binata, corresponding to the differing phenologies of each host plant species. These observations generated the following hypotheses for future testing: (1) S. n.sp_BINA move between host species to prioritise prey availability, and (2) S. n.sp_BINA eclosion is triggered by the same moisture and/or temperature cues as their hosts so that hatching coincides with prey availability.

Identifying areas of high biodiversity value is critical for effective conservation. Similarly, identifying gaps in existing protected area networks is fundamental to determining where new areas are needed to better conserve biodiversity. We conducted a spatial prioritisation analysis for forest and woodland-dependent species across Victoria using the program Zonation, integrating datasets on IBRA bioregions, EVC groups, forest disturbance and habitat models for rare and threatened taxa. Our study addressed three questions: (Q1) Where are the highest priority areas for rare and threatened forest and woodland species? (Q2) Where are the highest priority areas in relation to the current protected area network across particular regions? (Q3) Are there additional high-priority areas that would need to be included in the protected area network? Our results highlighted key IBRA subregions with the highest conservation priority for forest and woodland dependent species, including Murray Fans, Gippsland Plain, Otway Ranges, Strzelecki Ranges, Goldfields, Highlands - Northern Fall and East Gippsland Lowlands. Unprotected state forests previously zoned for logging were consistently associated with lower conservation value scores, likely due to degraded forest condition. In contrast, state forests zoned as special protection zones (SPZs) achieved the same scores as those assigned protection under IUCN category II, such as national parks. Natural Features Reserves and IUCN protected area categories III and V featured the highest scoring land tenures. Our gap analysis revealed that for several IBRA subregions, most top-priority areas (Zonation bin scores 0.9–1.0) were in unprotected land tenures, particularly state forests. These included the IBRA subregions of the Highlands - Southern Fall and Highlands - Northern Fall. Our findings underscore the need to extend formal protection to high conservation value areas in underrepresented IBRA subregions, primarily through the expansion of national parks and other kinds of legislated conservation reserves across specific subregions.

Understanding diet selection in threatened species is crucial for effective conservation planning, particularly where bushfires alter food availability and quality. In Australian eucalypt forests, Eucalyptus leaves are the primary food for several arboreal marsupials, such as the southern greater glider (Petauroides volans). Some eucalypt species regrow leaves epicormically after fire, and these leaves can differ in concentrations of deterrent compounds like unsubstituted B-ring flavanones (UBFs) compared to adult foliage. Little is known about how greater gliders respond to variation in UBF concentrations or their use of post-fire regrowth. We investigated whether UBF and available nitrogen concentrations in epicormic regrowth and adult leaves of Eucalyptus fastigata and E. sieberi influenced feeding by greater gliders. Epicormic leaves had lower UBF concentrations than adult leaves in both eucalypt species, whereas available nitrogen concentrations were higher in epicormic leaves of E. fastigata but lower in E. sieberi. Greater gliders consumed both leaf phases in similar amounts. There was a negative relationship between UBFs and food intake in E. fastigata, but UBF concentrations were very low in this species so other constituents may have been driving the response. Intake of E. sieberi, which had substantially higher UBF concentrations, was best explained by an interaction between UBFs and available nitrogen, but the role of UBFs remained unclear. Leaf intake correlated well with near-infrared spectral properties, further demonstrating that foliar chemical composition affects feeding but also suggesting that unmeasured foliar chemicals are influential. Overall, the findings show that greater gliders are relatively tolerant of UBFs, consistent with observations that they eat many monocalypt species in the wild. Importantly, the results give confidence that greater gliders can consume epicormic regrowth following fire in some forest types, despite post-fire changes in leaf quality.