Climate Change

• Changes in land use, such as urbanization and deforestation, can also contribute to climate change by altering the Earth's surface and affecting the balance of greenhouse gases.
• Natural changes are usually slow enough for migratory abilities of organisms to allow adjustments of ranges
• Migrations and range shifts have happened routinely through geological time
• Strong selection can produce rapid evolutionary responses
• Species have some capacity to disperse
• Anthropogenic changes can happen so fast that species may not be able to migrate or evolve
• Range of snowfall = 4.7 - 16.4 m
• Mean snowfall since 1975 = 11.1 m
• The figure shows the current and historical latitudinal locations for many plant and animal species located across the entire globe
• Graham Pyke conducted altitudinal transects censuses of bumble bee species in 1974
• Pyke's censuses were repeated by University of Toronto ROP399 students in 2006-2007
• Species A, B, and C have responded to climate change by shifting their range
• Area has warmed by 0.4°C, but no major land use changes have occurred
• Ranges of tolerance and ecological niche modeling are used to predict how far the range of a species will need to shift
• Pikas in The Great Basin are found in many small mountain ranges surrounded by desert
• Prof. John Stinchcombe: 'Modeling species loss from sky islands with climate change (1996)'
• American Pikas are adapted for life in high, cold mountains with a lethal temperature of around 27°C
• Mammals on mountain ranges in the Great Basin are considered in the model assumptions for species loss due to climate change
• Species range shift prediction process

  Species found in suitable conditions -> Measure ecological conditions to produce an "envelope of suitability" -> Use GCM to predict future conditions -> Map future suitable conditions -> Predict range shift
• Pronghorn "antelope" are migratory grazers of open grassland
• In 2003, pikas were resampled in 25 mountain ranges where they had been found earlier, and they were extirpated in 7 of the 25 ranges
• Population decline of Bramble Cay melomys has been severe, with a significant decrease in numbers over the years
• Pronghorn are known as the "American Cheetah" and have a skeleton convergently similar to the true African cheetah
• Climate-change migrations will be hampered by human-altered landscapes
• Bramble Cay melomys is the only endemic mammal species of the Great Barrier Reef and relies on herbaceous cover for food and shelter
• Pronghorn are the fastest North American mammal
• Bramble Cay melomys (Melomys rubicola) is a small rodent found only on Bramble Cay, a tiny isolated island near Australia and Papua New Guinea
• Pronghorn have a sad history of whole herds being killed at fences in winter
• Population census: ~98 individuals

  1998
• Population Recovery Plan initiated

  2008
• No Bramble Cay melomys were found in 2011 and 2014, and there was no sign of their presence on the island. The last known sighting of a living Bramble Cay melomys was in 2009.
• Survey conducted

  Dec 2011 & March 2014
• Study confirms the extirpation of the Bramble Cay melomys from Bramble Cay
• Researchers concluded that ocean inundation caused dramatic habitat loss. Seawater inundation killed vegetation and destroyed habitat and food sources. Sea levels in this area have risen avg. 6 mm per year between 1993-2010 – twice the global average. Sea-level rise can make extreme weather and waves very destructive to low islands like Bramble Cay
• Population of Bramble Cay melomys declined rapidly due to human-caused climate change, leading to its extinction between 2016-2019. It was the first mammal declared extinct due to climate change
• Evolutionary responses to global climate change include tracking genetic change, focusing on genetic polymorphisms or Mendelian traits. Melanic dominant to orange coloration provided thermal advantage under specific conditions
• Change in temperature gradients due to climate warming eliminated fitness advantage of melanics, leading to evolution in response to climate change