Spatial patterns and associations of dominant woody species in desert–oasis ecotone of South Junggar Basin, NW China

Abstract

Spatial patterns and associations of plant species are important for revealing how species interact with each other and with the environment, and hence have important implications for the understanding of species interaction and underlying ecological processes with apparent patterns in temperate desert vegetation. In this paper, the function g (r) was used to characterize the spatial patterns and associations of four dominant woody species in three 1-ha desert plant plots in the desert-oasis ecotone of South Junggar Basin, NW China. The complete spatial randomness null model showed four species exhibited significant aggregations at small scales (<20 m). Anabasis aphylla and Nitraria roborowskii, Haloxylon ammodendron and Reaumuria songarica were spatially positive associations at small scales with the independent null model, while A. aphylla and H. ammodendron, A. aphylla and R. songarica, R. songarica and N. roborowskii species pairs exhibited negative associations at small or moderate scales (20-60 m) in our study. The random labeling null model showed that dead standing plants of A. aphylla were largely determined by the combined effects of intra-and interspecific competition. In addition, the results also indicated that the two main factors of habitat heterogeneity and sandy desertification play important roles in determining spatial distribution patterns and associations of woody species in the desert-oasis ecotone of South Junggar Basin. Thus, the differences of species features in spatial patterns and associations should be paid more attention when planning afforestation and developing conservation strategies.

Elephant‐induced damage drives spatial isolation of the dioecious palmBorassus aethiopumMart. (Arecaceae) in the Pendjari National Park, Benin

“…However, some disturbances (e.g. fires, anthropogenic activities, introduction of invasive species, megaherbivores' damages) may occur and alter the original SP and thus the underlying processes (Chu, Wang & Zhang, ; Riginos et al ., ). From a demography perspective, these disturbances may induce growth, stability or decline of the populations (Schmidt et al ., ).…”

Point Pattern Analysis of Different Life Stages of Haloxylon ammodendron in Desert-oasis Ecotone

“…Sustainable forest management in arid and semi-arid areas has long been interested in managing interspecific relations dominated by desert woody species, but intraspecific competition also is a very important question [34]. In this paper, we showed that intraspecific competition was an important process in four different life stages (seedlings, juveniles, mature, overmature) in a H. ammodendron population in the Ecotone desert-oasis of South Junggar Basin.…”

“…Micro-topography creates biotic heterogeneities (e.g., seed tree abundance, intraspecific competition) and abiotic heterogeneities (e.g., soil organic, salt, water), which act as a filter for seed availability, seedling germination, and establishment in arid and semi-arid environments [27,34]. Thus, for H. ammodendron with limited seed dispersal distance, seed availability may be the main limiting factor for recruitment in severely heterogeneities topography areas and result in competitive relation and aggregated patterns in desert areas [11].…”

“…Furthermore, field observations also confirmed that almost all recruits were observed in low severity burned areas. In addition, drought is an important disturbance in the desert community, which can change vegetation dynamics [10,34]. Because community succession is a long-term process where initial conditions can be critically important, plant recruitment after drought severity provides a critical observational window to predict future spatial patterns and stand dynamics [11,27].…”

Spatial Differentiation Characteristics of Alpine Grassland Patches in the Source Region of the Yellow River and Its Ecological Significance

“…Studying the spatial differentiation characteristics of grassland patches is the most direct and practical method for assessing ecosystem status (Kefi, Alados, 2010). It is closely related to ecosystem function and promotes the understanding of ecological phenomena covered by spatial pattern representation (Meloni, Granzotti, 2017), so as to better understand the succession characteristics of patches in alpine grassland degradation process (Chu, Wang, 2014). In the region where this study is located, the ecological pressure resistance is poor and the aggregation scale gradually decreases, thus forming a patchy spatial pattern.…”