Abstract
Biodiversity maintenance mechanisms have been central to the study of community ecology, and the negative density dependence effect plays an important role in maintaining species diversity in forest communities. However, the strength and direction of the negative density dependence effect may change at different latitudinal gradients, and theory predicts that the negative density dependence effect increases with decreasing latitude. Using three provinces in northeastern China as the study target, we selected forest ecosystems in 15 locations according to the latitude gradient and analyzed the mixing of large- and small-diameter trees and adjacent tree species at different latitudinal gradients by the second-order characteristic function of mark mingling (The species mingling was used as “constructed marks” and we developed a second-order characteristic function of mark mingling useful for comparing spatial species mingling via random assignment of species patterns at specific ecological scales). It was found that the tree species mixed level of the large trees was higher, that of the small trees was lower in the stands at the middle and low latitudes (40, 41, and 43), and the tree species mixed level of the large or small trees was lower in the stands at high latitudes (45 and 46). Also, the level of mixing of large trees with surrounding tree species was significantly different among latitudes within the small scale (0–5 m). More importantly, the peak value of the difference in the second-order characteristic function of mark mingling (Δv(r)) of the stand increased gradually with decreasing latitude. The results indicated that the difference in tree species mixing degree between large and small trees was increasing, and this phenomenon was more obvious at the small scale (0–10 m). In general, we found that the negative density dependence effect in the late successional forest system showed a variation trend with latitude gradient, which showed that with the decrease in latitude, the negative density dependence effect in the stands was increasing. The results showed that in temperate forests, in low-latitude stands (40–43° N), there is significant peak in species mingling differences at small scales (0–10 m). Spatial heterogeneity thinning should be prioritized, and rare tree species should be replanted within a 10 m radius to alleviate intraspecific competition. In contrast, in high-latitude stands (45–46° N), human disturbance should be reduced to maintain the natural community structure. These measures can provide precise management strategies for regional biodiversity conservation. This study revealed the response of the intensity of the negative density dependence effect to changes in latitudinal gradients, and provides new ideas for maintaining and controlling regional species diversity.
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Claims 11
Claim · model-written summary
In Korean pine stands at middle and low latitudes, the tree species mixing level of large trees was higher.
- Taxon
- Korean pine
Pinus koraiensist0 - Outcome
- tree species mixed level of the large treese1
- Direction
- highere1
- Setting
- middle and low latitudes (40, 41, and 43)e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e1“the tree species mixed level of the large trees was higher, that of the small trees was lower in the stands at the middle and low latitudes (40, 41, and 43)”
Claim · model-written summary
In Korean pine stands at middle and low latitudes, the tree species mixing level of small trees was lower.
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- that of the small treese1
- Direction
- lowere1
- Setting
- middle and low latitudes (40, 41, and 43)e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e1“the tree species mixed level of the large trees was higher, that of the small trees was lower in the stands at the middle and low latitudes (40, 41, and 43)”
Claim · model-written summary
In Korean pine stands at high latitudes, the tree species mixing level of large or small trees was lower.
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- tree species mixed level of the large or small treese2
- Direction
- lowere2
- Setting
- high latitudes (45 and 46)e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e2“the tree species mixed level of the large or small trees was lower in the stands at high latitudes (45 and 46)”
Claim · model-written summary
The mixing of large trees with surrounding tree species differed significantly among latitudes at the small scale (0–5 m).
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- the level of mixing of large trees with surrounding tree speciese3
- Setting
- within the small scale (0–5 m)e3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e3“the level of mixing of large trees with surrounding tree species was significantly different among latitudes within the small scale (0–5 m)”
Claim · model-written summary
The peak value of the difference in the mark-mingling function increased gradually with decreasing latitude.
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- the peak value of the differencee4
- Direction
- increasede4
- Setting
- decreasing latitudee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e4“the peak value of the difference in the second-order characteristic function of mark mingling (Δv(r)) of the stand increased gradually with decreasing latitude”
Claim · model-written summary
The difference in tree species mixing degree between large and small trees was increasing, more obviously at the small scale (0–10 m).
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- difference in tree species mixing degree between large and small treese5
- Direction
- increasinge5
- Setting
- at the small scale (0–10 m)e5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e5“The results indicated that the difference in tree species mixing degree between large and small trees was increasing, and this phenomenon was more obvious at the small scale (0–10 m)”
Claim · model-written summary
In low-latitude stands (40–43° N) there is a significant peak in species mingling differences at small scales (0–10 m).
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- peak in species mingling differencese7
- Setting
- low-latitude stands (40–43° N)e7
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e7“in low-latitude stands (40–43° N), there is significant peak in species mingling differences at small scales (0–10 m)”
Claim · model-written summary
The negative density dependence effect in the stands increased as latitude decreased.
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- negative density dependence effecte6
- Direction
- increasinge6
- Setting
- the decrease in latitudee6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e6“with the decrease in latitude, the negative density dependence effect in the stands was increasing”
Claim · model-written summary
Spatial heterogeneity thinning should be prioritized in the stands to maintain regional diversity.
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- Spatial heterogeneity thinninge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e0“Spatial heterogeneity thinning should be prioritized, and rare tree species should be replanted within a 10 m radius to alleviate intraspecific competition”
Claim · model-written summary
Rare tree species should be replanted within a 10 m radius to alleviate intraspecific competition.
- Taxon
- Korean pinePinus koraiensist0
- Outcome
- rare tree species should be replanted within a 10 m radiuse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e0“rare tree species should be replanted within a 10 m radius to alleviate intraspecific competition”
Claim · model-written summary
In high-latitude stands (45–46° N), human disturbance should be reduced to maintain the natural community structure.
- Taxon
- Korean pinePinus koraiensist0
- Treatment
- human disturbance should be reducede0
- Outcome
- to maintain the natural community structuree0
- Setting
- high-latitude stands (45–46° N)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Latitudinal Gradients in Negative Density Dependence of Broad-Leaved Korean Pine Forests in Northeastern China”
e0“In contrast, in high-latitude stands (45–46° N), human disturbance should be reduced to maintain the natural community structure”