Understanding temporal behavioural patterns in animals can be crucial to their conservation management. Emergence timing in bats, that is, the decision on when to depart day-roosts for foraging, is one such example and is well studied in Northern Hemisphere bats. The emergence timing of New Zealand long-tailed bats () is not yet fully understood, including when and where they may be vulnerable to threats.
View Article and Find Full Text PDFHigh-latitude lizards live in environments where ambient air temperature at night is frequently below retreat temperatures, which likely has implications for nocturnal emergence and activity. However, patterns of lizard activity at night under current temperate climates are poorly understood, a situation that limits our understanding of potential effects of climate change. We investigated patterns of nocturnal emergence and activity in the cold-adapted, viviparous gecko ( 'Otago/Southland').
View Article and Find Full Text PDFLizards that inhabit high-latitude alpine zones are exposed to extreme temperatures and long winters and most are diurnal heliotherms. Yet some poorly known nocturnal species exist in such locations, including several viviparous geckos from New Zealand. We studied the orange-spotted gecko (Mokopirirakau 'Roy's Peak'), a cryptic, nocturnal and viviparous lizard known only from the alpine zone (1150-1800 m a.
View Article and Find Full Text PDFDeveloping and validating methods to determine trends in populations of threatened species is essential for evaluating the effectiveness of conservation interventions. For cryptic species inhabiting remote environments, this can be particularly challenging. Rock wrens, Xenicus gilviventris, are small passerines endemic to the alpine zone of southern New Zealand.
View Article and Find Full Text PDFUnderstanding the interaction between upper voluntary thermal limit (VT) and water loss may aid in predicting responses of ectotherms to increasing temperatures within microhabitats. However, the temperature at which climate heating will force cool-climate nocturnal lizards to abandon daytime retreats remains poorly understood. Here, we developed a new laboratory protocol for determining VT in the retreat-dwelling, viviparous 'Otago/Southland' gecko, based on escape behaviour (abandonment of heated retreat).
View Article and Find Full Text PDFFormulations of glyphosate-based herbicides continue to dominate the global herbicide market, while there continue to be concerns regarding the impact of this herbicide on non-target organisms. Research also indicates that the additives within certain glyphosate formulations, such as surfactants, are actually more toxic than the glyphosate active ingredient alone. Concerns arise in particular when glyphosate formulations are proposed for vegetation control in areas inhabited by rare or threatened species.
View Article and Find Full Text PDFMechanistic models can help resolve controversy over the responses of mast seeding plants to future environmental change. We evaluate drivers of mast seeding by: developing and validating a new mechanistic resource-based model of mast seeding using four 40-yr Chionochloa (snow tussock) datasets; and comparing the performance of competing empirically-based statistical models, that aim to approximate the mechanisms underlying mast seeding, in explaining simulated and observed data. Our mechanistic model explained 90-99% of the variation in Chionochloa flowering, with higher rates of stored resource mobilisation and lower probability of climatic induction of flowering occurring at lower fertility sites.
View Article and Find Full Text PDFUnderstanding the mechanisms underlying population declines is critical for preventing the extinction of endangered populations. Positive feedbacks can hasten the process of collapse and create an 'extinction vortex,' particularly in small, isolated populations. We provide a case study of a male-biased sex ratio creating the conditions for extinction in a natural population of tuatara (Sphenodon punctatus) on North Brother Island in the Cook Strait of New Zealand.
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