It is no coincidence that many of the herbivorous mammals to bring up their young in the early spring to the world: To sprouts this time, the first fresh Green and the newly sprouting plants that are particularly nutritious. Because the first tender leaves have a high energy and protein content, while the plants later, during flowering, increasingly less generous support to produce material and stems. The right, early Timing of birth ensures that both mother and child, an optimum food supply.

Vegetation responds to five to seven times faster

start out by the mild Winter and rising temperatures, the plants almost everywhere earlier and earlier. The vegetation period is premature depending on the Region for a few days. This raises the question of whether the deer in this shift can customize. To find out, to Maik Rehnus of the Swiss Federal research Institute for forest, snow and landscape WSL, and his colleagues, the sets mine 8983 fawn evaluated, which were born in the years 1971 to 2015 in Switzerland. This data is compared with information related to the beginning of the vegetation period and the first mowing of the meadows.

It showed: In the examined 45 years of vegetation at the beginning of the 20 days, and the hay cut by 14 days, premature. The growing season began during this time each year, to 0.45 days earlier, the first hay cut of 0.32 days, the researchers found. By contrast, relies mine of the fawns began to shift significantly slower. Have you moved only to around 0.06 days per year forward. "The birth dates changed on average 7.5 Times slower than the beginning of the vegetation period and five Times slower than the blossom", reports Rehnus and his Team.

Small-scale farming and Migration to higher altitudes

help In relation to the deer this is a good news and bad news, as the scientists explain. Because even though you are based for your sit date actually primarily based on the length of the day, they seem to be the first adaptation to climate change and the shift in the vegetation periods to show. But, unfortunately, the pace of this adjustment is not enough to keep up with the plant world. "This will result in a growing Divergence between optimal food availability and birth, in all altitudes," said the researchers.

In the lower altitudes, this has already led to the fact that the lie puts mine in part, outside the period of optimal food supply. Still, however, the deer can compensate for this: "thanks to the relatively small-scale and mosaic-like management of various agricultural crops that grow at different points in time, the deer also in accordance with the optimal conditions in the meadow land, enough nutrition," says Rehnus' colleague, Kurt Bollmann. In the higher elevations of the mine, and vegetation Sets fit periods yet still together, because that is where the spring starts later. Possibly this could lead to that deer in the mountain pull layers of regions in the future, more and more in the higher slope, speculate the researchers.

source: Swiss Federal research Institute for forest, snow and landscape WSL; technical article: Ecosphere, doi: 10.1002/ecs2.3144

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Date Of Update: 01 July 2020, 11:27