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

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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.


Community weighted means of SLA and LDMC during the succession (CWM ± SE). Subfigures: CWMs of SLA calculated with alfalfa (A); CWMs of SLA calculated without alfalfa (B); CWMs of LDMC calculated with alfalfa (C); CWMs of LDMC calculated without alfalfa (D). Different letters denote significant differences obtained with Tukey's test (p < .05)
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ece32869-fig-0001: Community weighted means of SLA and LDMC during the succession (CWM ± SE). Subfigures: CWMs of SLA calculated with alfalfa (A); CWMs of SLA calculated without alfalfa (B); CWMs of LDMC calculated with alfalfa (C); CWMs of LDMC calculated without alfalfa (D). Different letters denote significant differences obtained with Tukey's test (p < .05)

Mentions: CWM of SLA was negatively affected by field age in both cases; however, the age effects were only marginally significant (with alfalfa: F = 3.86; p = .056; without alfalfa: F = 2.60; p = .098; Figure 1A, B). Age effect was significantly positive in case of CWM of LDMC in both types of analyses (with alfalfa: F = 6.60; p = .014; without alfalfa: F = 10.05; p = .004; Figure 1C, D). We did not detect significant age effect in case of CWM of LA (with alfalfa: F = 0.26; p = .854; without alfalfa: F = 0.80; p = .528).


New aspects of grassland recovery in old ‐ fields revealed by trait ‐ based analyses of perennial ‐ crop ‐ mediated succession
Community weighted means of SLA and LDMC during the succession (CWM ± SE). Subfigures: CWMs of SLA calculated with alfalfa (A); CWMs of SLA calculated without alfalfa (B); CWMs of LDMC calculated with alfalfa (C); CWMs of LDMC calculated without alfalfa (D). Different letters denote significant differences obtained with Tukey's test (p < .05)
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getmorefigures.php?uid=PMC5383495&req=5

ece32869-fig-0001: Community weighted means of SLA and LDMC during the succession (CWM ± SE). Subfigures: CWMs of SLA calculated with alfalfa (A); CWMs of SLA calculated without alfalfa (B); CWMs of LDMC calculated with alfalfa (C); CWMs of LDMC calculated without alfalfa (D). Different letters denote significant differences obtained with Tukey's test (p < .05)
Mentions: CWM of SLA was negatively affected by field age in both cases; however, the age effects were only marginally significant (with alfalfa: F = 3.86; p = .056; without alfalfa: F = 2.60; p = .098; Figure 1A, B). Age effect was significantly positive in case of CWM of LDMC in both types of analyses (with alfalfa: F = 6.60; p = .014; without alfalfa: F = 10.05; p = .004; Figure 1C, D). We did not detect significant age effect in case of CWM of LA (with alfalfa: F = 0.26; p = .854; without alfalfa: F = 0.80; p = .528).

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.