从我读到的关于灌木丛入侵，它通常听起来像坏事，可能是土地退化的症状。对我来说，这听起来违反直觉，因为灌木丛的入侵实际上包括
如果有的话，这听起来像是一个自然收回其权利的理想案例，那么从保护的角度来看，这为什么会是一件坏事呢?< / p >
In the long term, in certain situations, this can turn out to be detrimental overall if the numbers of predator species are reduced too much and the number of prey species can become too much and they could overgraze an area ultimately leading to desertification and erosion. It all depends on the species affected by bush encroachment.
Additionally, changing a landscape from savanna to bush increases the potential for more destructive wildfires. Wooded landscapes burn at higher temperatures, which can affect the nutrient levels of soil, produce large burn scars which could increase the possibility of desertification and it can lead to a greater loss of life of flora and fauna.
这个答案是基于我对苔原制度的了解，那里也发生了灌木丛/灌木的入侵。< / p >
In these areas the expansion of shrub coverage replaces existing vegetation such as lichen and moss-dominated plant communities leading which causes large changes in tundra biome.
Although the shrub vegetation itself acts as a carbon sink the effect of vegetation change causes decreases albedo e.g., the darker shrub vegetation absorbs warmth from the sunlight compared to the lighter lichens, mosses, bare ground (and plain snow-cover) that reflect the solar radiance. Thus the effect of shrub encroachment can have warming effect on the climate (that may or may not exceed the increased carbon sink of shrub vegetation, still under a debate I think).
Wildfires were already mentioned, but they might increase also in the northern areas. In addition, the ground temperatures and thus microbial activity could change, leading for example to a increased decomposition and nutrient cycling.
For tundra ecosystems see f.e. Shrub expansion in tundra ecosystems: dynamics, impacts and research priorities (2011). Myers-Smith et. Environ. Res. Lett. 6 (2011) 045509