Natural population structure and spatial distribution pattern of rare and endangered species Dacrydium pectinatum

ABSTRACTThis study aimed to analyze the vertical and diameter structure and the spatial distribution pattern of Bauhinia cheilantha in two Caatinga fragments in Sergipe, Brazil, at different regeneration stages. Thirty plots were demarcated in area I (Canindé de São Francisco and Poço Redondo), which has vegetation regeneration, and 25 plots in area II (Porto da Folha) with preserved vegetation, both having 400 m2. All B. cheilanthaindividuals had their height and circumference (circumference at breast height > 6 cm) measured. Possible differences in height and diameter at breast height were tested in the two populations by using Student’s T-test. The distribution pattern of species was calculated through Payandeh’s index. We sampled 154 B. cheilantha individuals, equivalent to 33.3% of the plots in area I and in 1,027 individuals in area II, totaling 100% frequency. Height and the diameter of the two populations were statistically different, where AI achieved all values lower than AII. The spatial distribution pattern of B. cheilantha found in both areas was aggregate, with values of 11.85 and 9.00, respectively. Thus, it became clear that the population in AII is at a more advanced successional status than AI, due to its longer conservation time.

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Competition Restricts the Growth, Development, and Propagation of Carpinus tientaiensis: A Rare and Endangered Species in China

Forests ◽

10.3390/f12040503 ◽

2021 ◽

Vol 12 (4) ◽

pp. 503

Author(s):

Liangjin Yao ◽

Yuanke Xu ◽

Bo Jiang ◽

Chuping Wu ◽

Weigao Yuan ◽

...

Keyword(s):

Spatial Distribution ◽

Endangered Species ◽

Spatial Scale ◽

Population Distribution ◽

Large Diameter ◽

Small Diameter ◽

Dynamic Monitoring ◽

Small Scale ◽

Rare And Endangered Species ◽

Rare And Endangered

The protection and propagation of rare and endangered species are key to the preservation of their population development; however, due to the scarcity of individuals, the potential effects and status of rare and endangered species in the whole forest ecosystem are still poorly understood. Using data from a 60 × 140 m forest dynamic monitoring sample of the Carpinus tientaiensis (Betulaceae) species in Zhejiang of Southeast China. We assessed the population distribution and diameter at breast height (DBH) structure of the Carpinus tientaiensis species, which was a rare and endangered species, as well as intra- and interspecific correlation with other species. The results show that saplings (1 cm ≤ DBH < 5 cm) and juveniles (5 cm ≤ DBH < 10 cm) were more aggregated than larger individuals (DBH ≥ 20 cm) of Carpinus tientaiensis. The DBH size structure of all the trees shows an obvious inverted “J” distribution. With an increase in the DBH size category, the number of individuals gradually decreases. Due to the diffusion limitation, the spatial distribution patterns of all the tree individuals and roof geese in the sample land are increased at a small spatial scale, and as the spatial scale increases, the degree of aggregation decreases gradually. The relationship between different diameter stages of the population of Carpinus tientaiensis showed a consistent general trend. The spatial distribution of individuals with a large diameter on a small scale was significantly positively correlated (p < 0.001). With an increase in the scale, there was no significant correlation (p > 0.05) between individuals with a large diameter and individuals with a small diameter. There was no significant correlation (p > 0.05) between the population of Carpinus tientaiensis and other species in the sample, and the strong unidirectional competition of other species in the sample can be seen by the competition index. We found that interspecific competition restricts the growth and expansion of Carpinus tientaiensis, and it has adopted different ecological strategies to coexist with a population of common tree species occupying a similar living space.

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Cattle influence on the population structure of yerba mate (Ilex paraguariensis) in Araucaria Forest

Ciência Rural ◽

10.1590/0103-8478cr20190191 ◽

2019 ◽

Vol 49 (11) ◽

Author(s):

Lilian Iara Bet Stedille ◽

Edicléa Zulian Pires ◽

Juliano Pereira Gomes ◽

Newton Clóvis Freitas da Costa ◽

Alison Paulo Bernardi ◽

...

Keyword(s):

Population Structure ◽

Spatial Distribution ◽

Data Collection ◽

Distribution Pattern ◽

Spatial Distribution Pattern ◽

Diameter Distribution ◽

Ilex Paraguariensis ◽

Random Pattern ◽

Yerba Mate ◽

Araucaria Forest

ABSTRACT: This study characterized the demography and spatial pattern of a yerba mate (Ilex paraguariensis A.St.-Hil) population covering areas with different use histories (Presence and Absence of Cattle) in a Araucaria Forest. Data collection was performed in three ha, half in each area. The frequency of individuals by height, spatial distribution pattern, diameter distribution (for reproductive individuals) and sexual ratio were evaluated. An inverted “J” pattern predominated, being exclusive to an area with Cattle Presence, a place which presented a lower density of individuals. The predominant spatial distribution pattern was aggregated, and the reproductive individuals have a preferentially random pattern at the shortest distances. Results indicated that cattle presence changes the density of I. paraguariensis individuals and the proportion of individuals in the evaluated demographic classes.

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