Climate change is also affecting the natural environment. It is already changing, and expectations are that this development will continue in the future. The increasingly frequent dry summers are causing particularly great changes and can cause damage to the natural environment. This map narrative explains how climate change is affecting the natural environment and how this is already manifest. It also shows how this information can be used to map out the potential impact on biodiversity.
Which species of vegetation are susceptible to climate change?
Increasing drought can cause particular damage to nature. However, not all species of vegetation are affected by drought. The increasing drought resulting from climate change is particularly harmful to species depending on shallow groundwater. Drought issues in areas featuring groundwater-dependent nature can be combated by adopting water management. That is why this map narrative focuses on groundwater-dependent species, rather than on such drought-loving species as dry heather.
How is climate change affecting the natural environment?
One of the consequences of climate change is that plant and insect species from southern countries are starting to feel at home in the Netherlands, on account of the higher temperatures. In addition, the drier and warmer growth seasons are affecting the volume of earth moisture available to plants. Drier summers can lead to groundwater levels sinking deeper and brooks running dry. These hydrological ramifications are exacerbated as drinking water consumption among residents increases and farmers up to their irrigation processes. This is what happened in, e.g., the dry summers of 2018, 2019, and 2020.
Falling groundwater levels can result in the breakdown of organic matter in the soil, which benefits such rapidly growing and commonly found plants as Brambles and Purple Moor Grass. Groundwater seeping up in wet areas (under seepage) tends to be poor in nutrients and contains substances that prevent soil acidification. If drought cuts off such under seepage flows, the soil may acidify, in which case chances are that many unique plant species will disappear.
Groundwater-dependent forest (marshy forest) before (left) and after (right) structural groundwater level reduction: Marsh Marigold has disappeared from the undergrowth, being replaced by Bramble and Stinging Nettle, two rapid growers benefiting from the nutrients released in the breakdown of organic matter.
Another possible consequence of increasing drought and heat is that evaporation can be greatly reduced due to a lack of soil moisture. This is seen in dry sandy areas, such as the Veluwe and the dunes. A surprising consequence of this may be that more precipitation flows into groundwater on an annual basis, which is beneficial to the streams and marshes that are fed by that groundwater.
What is already changing in the natural environment?
According to the KNMI WH scenario, the dry summers that we experienced in 2018, 2019 and 2020 will occur more frequently. We have already seen the impact of such dry summers. For example, we have witnessed the local mass death of certain tree and shrub species on dry, infertile sandy soils, such as Spruce, Oak, and Beech. Several peat moors, pools, and brooks ran dry, which spelt the end for many fish, amphibians, dragonflies, and butterflies. Several types of landscapes – peat moors, wet heath, pools, wet and moist lean meadows, and quaking bogs –saw their abundance of plant species go down. Several locations saw massive sections of heather die back. Dominant grass species such as Holcus Lanatus succumbed to the drought. In dry meadows, this created room for other species to develop, such as Oxeye Daisy, Mouse-ear Hawkweed, Yarrow, Yellow Bedstraw, Harebell, and Brown Knapweed. Ergo, for some drier meadows, the drought has actually proven advantageous.
With some changes, other factors may (also) play a part
With respect to these changes in the natural environment, it is important to realise that climate change is an insidious process, and additional processes may also be at play. Consequently, it is difficult to assess whether the changes are caused by climate change or (in part) by other processes. For example, soil and water qualities may be affected by the emission of over-fertilising and acidifying substances, such as nitrogen in ammonia form, or by dehydration of farmland.
Experts are already noticing that as a result of climate change, increasingly more plant and insect species from southern countries are finding their ways to the Netherlands, such as the Great Egret, the Swallowtail, and Love Grass. However, this cannot be attributed entirely to climate change: this development is fostered by urbanisation and international transport. Urbanisation is conducive to local warming, whilst international transport is responsible for the importation of exotic seeds.
