Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Desertification by Front Propagation?   Understanding how desertification takes place in different ecosystems is an
important step in attempting to forecast and prevent such transitions. Dryland
ecosystems often exhibit patchy vegetation, which has been shown to be an
important factor on the possible regime shifts that occur in arid regions in
several model studies. In particular, both gradual shifts that occur by front
propagation, and abrupt shifts where patches of vegetation vanish at once, are
a possibility in dryland ecosystems due to their emergent spatial
heterogeneity. However, recent theoretical work has suggested that the final
step of desertification - the transition from spotted vegetation to bare soil -
occurs only as an abrupt shift, but the generality of this result, and its
underlying origin, remain unclear. We investigate two models that detail the
dynamics of dryland vegetation using a markedly different functional structure,
and find that in both models the final step of desertification can only be
abrupt. Using a careful numerical analysis, we show that this behavior is
associated with the disappearance of confined spot-pattern domains as
stationary states, and identify the mathematical origin of this behavior. Our
findings show that a gradual desertification to bare soil due to a front
propagation process can not occur in these and similar models, and opens the
question of whether these dynamics can take place in nature.

1
The categories of this paper are: cs
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg