Asymmetric boundary shifts of tropical montane Lepidoptera over four decades of climate warming

Abstract

Aim To estimate whether species have shifted at equal rates at their leading edges (cool boundaries) and trailing edges (warm boundaries) in response to climate change. We provide the first such evidence for tropical insects, here examining elevation shifts for the upper and lower boundaries shifts of montane moths. Threats to species on tropical mountains are considered.Location Mount Kinabalu, Sabah, Malaysia. MethodsWe surveyed Lepidoptera (Geometridae) on Mount Kinabalu in 2007, 42 years after the previous surveys in 1965. Changes in species upper and lower boundaries, elevational extents and range areas were assessed. We randomly subsampled the data to ensure comparable datasets between years. Estimated shifts were compared for endemic versus more widespread species, and for species that reached their range limits at different elevations.Results Species that reached their upper limits at 2500-2700 m (n = 28 species, 20% of those considered) retreated at both their lower and upper boundaries, and hence showed substantial average range contractions (-300 m in elevational extent and -45 km 2 in estimated range area). These declines may be associated with changes in cloud cover and the presence of ecological barriers (geological and vegetation transitions) which impede uphill movement. Other than this group, most species (n = 109, 80% of the species considered) expanded their upper boundaries upwards (by an average of 152 m) more than they retreated at their lower boundaries (77 m).Main conclusions Without constraints, leading margins shifted uphill faster than trailing margins retreated, such that many species increased their elevational extents. However, this did not result in increases in range area because the area of land available declines with increasing elevation. Species close to a major ecological/geological transition zone on the mountain flank declined in their range areas. Extinction risk may increase long before species reach the summit, even when undisturbed habitats are available.

Ecological impacts of tropical forest fragmentation: how consistent are patterns in species richness and nestedness?

“…Fruitfeeding moths (Families Noctuidae and Geometridae) and butterflies (Family Nymphalidae) were sampled with traps baited with rotting banana, hung at stations at 100 m intervals along each transect. This guild comprises about 75 per cent of all nymphalid butterflies recorded on Borneo [64,65] but a much smaller proportion of noctuid and geometrid moths [66][67][68][69][70][71][72][73]. Traps were suspended 2 m above ground level at each station and fresh banana was added to the trap each day to ensure a mixture of fresh and well-rotted bait [74].…”

Rapid upslope shifts in New Guinean birds illustrate strong distributional responses of tropical montane species to global warming

“…Given that tropical species are hypothesized to be especially sensitive to temperature increases (either directly or via indirect ecological interactions), we additionally predicted that the magnitude of upslope shifts would closely match predicted shifts based on local temperature increases. We simultaneously tested two additional hypotheses, investigating whether upslope shifts at the leading range margin outpaced upslope shifts at the trailing range edge (21), and whether species' dietary preferences influenced upslope shifts (22,23). We then used our data in conjunction with recent tropical resurveys to test the tropical-species-are-strong-responders hypothesis, predicting that upslope shifts measured in tropical resurveys match predicted upslope shifts significantly more closely than for temperate-zone resurveys.…”

La restauración ecológica clásica y los retos de la actualidad: La migración asistida como estrategia de adaptación al cambio climático

“…La selección de especies que puedan ser candidatas ideales para la migración asistida debe considerar varios criterios. Por un lado, pueden ser aquellas especies con poblaciones pequeñas, distribución restringida, baja fecundidad o que están sufriendo algún declive por enfermedades o competencia con otras especies (Aitken et al, 2008;Chen et al, 2011;Loss, Terwilliger & Peterson, 2011). Otros criterios a tener en cuenta son: si están en alto riesgo por el cambio climático, si favorecen a la comunidad biológica del ecosistema receptor de forma que reduzcan el riesgo de extinción de las especies nativas, si mejoran la provisión de servicios ecosistémicos o si reducen los costos de manejo y conservación del ecosistema (Thomas, 2011).…”