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New aspects of grassland recovery in old ‐ fields revealed by trait ‐ based analyses of perennial ‐ crop ‐ mediated succession

View Article: PubMed Central - PubMed

ABSTRACT

Classical old‐field succession studies focused on vegetation changes after the abandonment of annual croplands or on succession after the elimination of cultivated crops. Perennial‐crop‐mediated succession, where fields are initially covered by perennial crops, reveals alternative aspects of old‐field succession theories. We tested the validity of classical theories of old‐field succession for perennial‐crop‐mediated succession. We formulated the following hypotheses: (1) functional diversity increases with increasing field age; (2) resource acquisition versus conservation trade‐off shifts toward conservation at community level during the succession; (3) the importance of spatial and temporal seed dispersal decreases during the succession; and (4) competitiveness and stress‐tolerance increases and ruderality decreases at community level during the succession. We studied functional diversity, trait distributions and plant strategies in differently aged old‐fields using chronosequence method. We found increasing functional richness and functional divergence, but also unchanged or decreasing functional evenness. We detected a shift from resource acquisition to resource conservation strategy of communities during the succession. The role of spatial and temporal seed dispersal was found to be important not only at the initial but also at latter successional stages. We found an increasing stress‐tolerance and a decreasing ruderality during succession, while the competitiveness remained unchanged at the community level. Despite the markedly different starting conditions, we found that classical and perennial‐crop‐mediated old‐field successions have some similarities regarding the changes of functional diversity, resource acquisition versus conservation trade‐off, and seed dispersal strategies. However, we revealed also the subsequent differences. The competitive character of communities remained stable during the succession; hence, the initial stages of perennial‐crop‐mediated succession can be similar to the middle stages of classical old‐field succession. Moreover, the occupied functional niche space and differentiation were larger in the older stages, but resources were not effectively utilized within this space, suggesting that the stabilization of the vegetation requires more time.

No MeSH data available.


Relative covers of species with transient (t), short‐term persistent (sp), and long‐term persistent (lp) seed bank types in differently aged alfalfa fields (%+SE)
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ece32869-fig-0003: Relative covers of species with transient (t), short‐term persistent (sp), and long‐term persistent (lp) seed bank types in differently aged alfalfa fields (%+SE)

Mentions: The field age positively affected the CWM of terminal velocity; however, the CWM was the highest in 3‐year‐old fields (F = 4.72; p = .035; Figure 2A). Age effect was significantly positive in case of CWM of epizoochory ranking index (F = 4.05; p = .049; Figure 2B). Cover of species group characterized by transient seed banks increased (F = 38.17; p < .001; Figure 3), while the cover of species group with long‐term persistent seed banks decreased with increasing field age (F = 14.32; p < .001; Figure 3). The age effect was not significant in case of species group characterized by short‐term persistent seeds (F = 1.14; p = .390; Figure 3).


New aspects of grassland recovery in old ‐ fields revealed by trait ‐ based analyses of perennial ‐ crop ‐ mediated succession
Relative covers of species with transient (t), short‐term persistent (sp), and long‐term persistent (lp) seed bank types in differently aged alfalfa fields (%+SE)
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383495&req=5

ece32869-fig-0003: Relative covers of species with transient (t), short‐term persistent (sp), and long‐term persistent (lp) seed bank types in differently aged alfalfa fields (%+SE)
Mentions: The field age positively affected the CWM of terminal velocity; however, the CWM was the highest in 3‐year‐old fields (F = 4.72; p = .035; Figure 2A). Age effect was significantly positive in case of CWM of epizoochory ranking index (F = 4.05; p = .049; Figure 2B). Cover of species group characterized by transient seed banks increased (F = 38.17; p < .001; Figure 3), while the cover of species group with long‐term persistent seed banks decreased with increasing field age (F = 14.32; p < .001; Figure 3). The age effect was not significant in case of species group characterized by short‐term persistent seeds (F = 1.14; p = .390; Figure 3).

View Article: PubMed Central - PubMed

ABSTRACT

Classical old&#8208;field succession studies focused on vegetation changes after the abandonment of annual croplands or on succession after the elimination of cultivated crops. Perennial&#8208;crop&#8208;mediated succession, where fields are initially covered by perennial crops, reveals alternative aspects of old&#8208;field succession theories. We tested the validity of classical theories of old&#8208;field succession for perennial&#8208;crop&#8208;mediated succession. We formulated the following hypotheses: (1) functional diversity increases with increasing field age; (2) resource acquisition versus conservation trade&#8208;off shifts toward conservation at community level during the succession; (3) the importance of spatial and temporal seed dispersal decreases during the succession; and (4) competitiveness and stress&#8208;tolerance increases and ruderality decreases at community level during the succession. We studied functional diversity, trait distributions and plant strategies in differently aged old&#8208;fields using chronosequence method. We found increasing functional richness and functional divergence, but also unchanged or decreasing functional evenness. We detected a shift from resource acquisition to resource conservation strategy of communities during the succession. The role of spatial and temporal seed dispersal was found to be important not only at the initial but also at latter successional stages. We found an increasing stress&#8208;tolerance and a decreasing ruderality during succession, while the competitiveness remained unchanged at the community level. Despite the markedly different starting conditions, we found that classical and perennial&#8208;crop&#8208;mediated old&#8208;field successions have some similarities regarding the changes of functional diversity, resource acquisition versus conservation trade&#8208;off, and seed dispersal strategies. However, we revealed also the subsequent differences. The competitive character of communities remained stable during the succession; hence, the initial stages of perennial&#8208;crop&#8208;mediated succession can be similar to the middle stages of classical old&#8208;field succession. Moreover, the occupied functional niche space and differentiation were larger in the older stages, but resources were not effectively utilized within this space, suggesting that the stabilization of the vegetation requires more time.

No MeSH data available.