The subtle effects of climate change on ecology
Celine Teplitsky, PhD
[Needs an introductory paragraph]
Keeping track of breeding time
For most species, spring is waking up and breeding time: plants are flowering, insects are emerging, frogs are calling, birds are singing… Each to their own rhythms. This rhythm is partly dictated by photoperiod (day/night lengh), but also to a large extent by temperature, and not all species respond in the same way to temperature or respond at the same time. For example, in Japan, the Chinese wild peach (Prunus davidiana) and the flowering cherry (Prunus yedoensi) have been flowering about 40 days earlier than normal in the last three decades, whereas the appearance date of the butterfly Pieris rapae (taken as a proxy of pollinator appearance) has not changed. This difference is due to species being sensitive to temperature at different moments [1].
A textbook example is the case of laying date in insectivorous birds. Females lay their eggs earlier egg-laying during warmer springs (Fig 1[CT1] ), which allows them to track the abundance of the caterpillars they use as main food source for their offspring [2,3]. In some populations, females manage to lay early enough but not in others [4], and the factors limiting the capacity of females to breed earlier are still unknown [5].
Fig. 1 Illustration of a mismatch in blue tits. Day 0 is laying date (varying among individuals and depending on temperature). In cool years (blue), the peak of caterpillar abundance matches the peak of offspring need (caterpillar abundance highest when food requirements are maximum), while during warmer years (red), the peak of caterpillar abundance precedes that of offspring needs.
Altogether, this kind of differences of response to spring temperature is common so that climate change can disrupt many interactions between species such plant/pollinators, competitors or predator/prey.
See also
https://www.wired.com/story/many-animals-arent-adapting-fast-enough-to-survive-climate-change/
Shrinking red knots and pervasive unpredictable effects of climate change
Original paper: Body shrinkage due to Arctic warming reduces red knot fitness in tropical wintering range
Red knots (Calidris canutus canutus) are long distance migrant birds. In the spring, this shorebird breeds in tundra and the Arctic cordillera. Their main food sources then are spiders and insects. The population studied by van Gils and collaborators [6] for more than 30 years breeds in Russia and overwinters in Mauritania.
In warmer years with earlier snowmelt, juveniles are smaller in terms of body mass but also beak length. These smaller sizes are likely due to lower food abundance, constraining chick growth.
At the end of the summer, birds migrate to their wintering grounds. The lost opportunity to grow in the Arctic is not compensated: juveniles are still smaller when they reach the wintering grounds. There, they switch diet to feed on hard shelled preys such as buried mollusks. One of the most abundant preys is a bivalve (clam like): Loripes lucinalis. This prey is buried about 35-40 mm deep in the sand, so that a bird with a 40mm bill access about two-thirds of the available Loripes, while individuals with a shorter bills only access one third of the preys and have to rely on lower quality food. This lower access to quality food has strong repercussions: shorter billed juveniles have lower survival rates than same age individuals with longer bills. This could partly explain the decline of this red knot population.
Climate change alters environmental conditions during the breeding season, deteriorating growth conditions for chicks who will become smaller juveniles and adults with dramatic consequences for survival thousands of kilometers away.
These stories illustrate how difficult to predict the effects of climate change are, notably because of the different networks of interactions in which species are embedded.
See also
The effects of habitat changes (urbanization, artificialisation): Of mayflies and roads
Humans are rapidly altering the environment, with huge obvious impacts when wild habitats are turned into agricultural lands or cities. However, environmental changes are also a myriad of other changes affecting how animals can perceive and react to their environments. A famous example is baby turtles going towards the cities rather than towards the sea because the light is brighter there. These evolutionary traps can have
Because animals have not evolve to distinguish this sources of information
Moon/cities vs turtles
Concept of evolutionary/ecological trap [7]
[8]
Effects of urbanization on birds’ lifestyles
Cascading effects
Vultures poisoning => no carcasses removals => many dogs => Rabies epidemics
Loss of predators => many ungulates => loss of trees
Something about urchins I don’t quite well remember
References
1. Doi H, Gordo O, Katano I. 2008 Heterogeneous intra-annual climatic changes drive different phenological responses at two trophic levels. Clim. Res. 36, 181–190. (doi:10.3354/cr00741)
2. Charmantier A, McCleery RH, Cole LR, Perrins C, Kruuk LEB, Sheldon BC. 2008 Adaptive phenotypic plasticity in response to climate change in a wild bird population. Science (80-. ). 320, 800–803. (doi:10.1126/science.1157174)
3. Visser ME, Holleman LJM, Gienapp P. 2006 Shifts in caterpillar biomass phenology due to climate change and its impact on the breeding biology of an insectivorous bird. Oecologia 147, 164–172. (doi:10.1007/s00442-005-0299-6)
4. Lyon BE, Chaine AS, Winkler DW. 2008 A matter of timing. Science (80-. ). 321, 1051–1052. (doi:10.1177/0363546515570023)
5. Bonamour S, Chevin L-M, Charmantier A, Teplitsky C. 2019 Phenotypic plasticity in response to climate change: the importance of cue variation. Philos. Trans. R. Soc. B Biol. Sci. 374, 2018.0178.
6. van Gils JA et al. 2016 Body shrinkage due to Arctic warming reduces red knot fitness in tropical wintering range. Science (80-. ). 352, 819–821. (doi:10.1126/science.aad6351)
7. Robertson BA, Rehage JS, Sih A. 2013 Ecological novelty and the emergence of evolutionary traps. Trends Ecol. Evol. 28, 552–560. (doi:10.1016/j.tree.2013.04.004)
8. Kriska G, Horváth G, Andrikovics S. 1998 Why do mayfly lay their eggs en masse on dry asphalt roads? J. Exp. Biol. 201, 2273–2286.