在巴丹吉林沙漠干旱胁迫群落中，利用分层贝叶斯模型评估了当地群落对护理灌木树种蒙古沙林的响应。在为期3年的试验中，每年的夏季降雨量形成了干旱压力的自然梯度。为了评估灌木对沿梯度聚集过程的影响，在灌木丛下和开阔生境中分别采集了个体样本，并同时测量了与胁迫耐受性和资源获取相关的四个性状。
\n这项研究的重点是干旱梯度最干旱端的限水群落，研究结果证实，通过环境过滤和生态位分化，可以推动群落的集结过程。更重要的是，在极端干旱胁迫下，这些集结机制的效率会降低，这可能表明，在气候变化的背景下，施惠植物在群落集结中的作用偶尔会消失，生物多样性丧失的风险也会增加。", "ds_source": "
现场试验获得。", "ds_process_way": "
测量物种的相对丰度：独立的蒙古沙蒿冠层下建立一个2 m × 2 m的样方，并在开放区域放置一个相同大小的样方。在这些样方中进行物种鉴定，并记录物种特有的丰度。
\n测量不同年份和不同生境的功能性状：根据两个生境中每个样方的丰度，在每个观察到的林下物种中随机选择2-5个成年个体。有5个品种由于数量太少而无法准确估计其性状值，因此被忽略。为获得可靠的估计，每个物种在不同的年份和栖息地取样30多个个体。当一个物种的适宜样本未达到这一数量时，在围栏样地的相同生境中随机采集额外的个体。\n
测量林下群落个体的最大冠宽为侧展(cm)。高度(cm)是指树冠延伸的上边界与地面之间的距离。以鲜叶面积与干叶质量之比为SLA (cm∙g-1)。LDMC (mg∙g-1)为叶片干质量与完全水合鲜质量之比。
\n测量土壤水分/含水量(SWC)：在每个样方的对角线收集4个土芯(直径5 cm，深度10-20 cm)，并在110°C下烘干48 h后进行重量测定。
\n测量土壤有机质(SOM)：每年随机选择10个成对样方，每个样方收集4个土芯，采用重铬酸盐氧化法。", "ds_quality": "
数据质量较好。", "ds_acq_start_time": "2017-01-01 00:00:00", "ds_acq_end_time": "2019-12-31 00:00:00", "ds_acq_place": "巴丹吉林沙漠", "ds_acq_lon_east": 100.15, "ds_acq_lat_south": 39.36666666666667, "ds_acq_lon_west": 100.03333333333333, "ds_acq_lat_north": 39.36666666666667, "ds_acq_alt_low": 1380.0, "ds_acq_alt_high": 1380.0, "ds_share_type": "login-access", "ds_total_size": 2301576, "ds_files_count": 2, "ds_format": "csv", "ds_space_res": "", "ds_time_res": "年", "ds_coordinate": "无", "ds_projection": "", "ds_thumbnail": "c33f394f-931e-4a78-a13e-3fe7df40a3b8.png", "ds_thumb_from": 2, "ds_ref_way": "", "paper_ref_way": "", "ds_ref_instruction": "", "ds_from_station": null, "organization_id": "0a4269e1-65f4-45f1-aeba-88ea3068eebf", "ds_serv_man": "敏玉芳", "ds_serv_phone": "0931-4967596", "ds_serv_mail": "ncdc@lzb.ac.cn", "doi_value": "", "subject_codes": [ "170.30" ], "quality_level": 3, "publish_time": "2023-07-25 10:58:14", "last_updated": "2026-01-14 11:06:10", "protected": false, "protected_to": null, "lang": "zh", "cstr": "11738.11.NCDC.ZENODO.DB3949.2023", "i18n": { "en": { "title": "The importance of facilitation on community assembly disappears under severe drought stress", "ds_format": "csv", "ds_source": "
Emsp; The data quality is good.", "ds_quality": "
The data quality is good.", "ds_ref_way": "", "ds_abstract": "
In the drought-stressed community in the Badain-Jaran Desert, the responses of the local community to the nurse shrub species Calligonum mongolicum Turcz. were evaluated using hierarchical Bayesian models. For the 3-year experiment, summer rainfall in each year formed a natural gradient of drought stress. To evaluate the shrub’s effects on the assembly process along that gradient, individual samples were collected in pairwise under-shrub and open habitats, and four traits related to stress tolerance and resource acquisition were measured simultaneously.
\nThis study focused on water-limited community that lies at the driest end of drought gradient and confirmed that facilitation can drive the assembly process through both environmental filtering and niche differentiation. More importantly, these assembly mechanisms are proven to become less efficient under extreme drought stress, which may suggest the occasionally disappearing role of benefactor plants on community assembly and an increasing risk of biodiversity loss in the context of climate change.
", "ds_time_res": "年", "ds_acq_place": "Badain Jaran Desert", "ds_space_res": "", "ds_projection": "", "ds_process_way": "To measure species relative abundance, a single 2 m × 2 m quadrat was established beneath the canopy of stand-alone Calligonum mongolicum, while another quadrat of the same size was placed in an open area. In these quadrats, species was identified, and the species-specific abundance was recorded.
\nTo measure functional traits at different years and habitats, we randomly selected 2-5 adult individuals for every observed understory species according to their abundance in each selected quadrat at both habitats. Five species were omitted from the analyses because they were too rare to accurately estimate trait values. To obtain robust estimation, more than 30 individuals for each species were sampled in different years and habitats. When the suitable samples of a species did not reach this amount, we randomly collected additional individuals from the same habitats in the fenced plots.
\nLateral spread (cm) was measured as the maximum crown width of individuals in the understory community. Height (cm) was measured as the distance between the extended upper boundary of the crown and the ground level. SLA (cm∙g-1) was determined as the ratio of fresh leaf area to leaf dry mass. LDMC (mg∙g-1) was determined as the ratio of leaf dry mass to fully rehydrated fresh mass.
\nTo measure soil moisture/water content (SWC), we collected four soil cores (5 cm diameter, 10–20 cm in depth) along the diagonal of each quadrat, and determined them gravimetrically after oven-drying for 48 h at 110°C.
\nTo measure soil organic matter (SOM), we randomly chose 10 pairwise quadrats each year, collected four soil cores within each quadrat, and applied the dichromate oxidation method.", "ds_ref_instruction": "" } }, "submit_center_id": "ncdc", "data_level": 0, "license_type": "CC BY 4.0", "doi_reg_from": "reg_outside", "cstr_reg_from": "reg_outside", "doi_not_reg_reason": null, "cstr_not_reg_reason": null, "is_paper_in_submitting": false, "ds_topic_tags": [ "巴丹吉林沙漠", "物种相对丰度", "生境功能性状", "土壤有机质", "最大冠宽" ], "ds_subject_tags": [ "地球化学" ], "ds_class_tags": [], "ds_locus_tags": [ "巴丹吉林沙漠" ], "ds_time_tags": [ 2017, 2018, 2019 ], "ds_contributors": [ { "true_name": "张格非", "email": "zhanggf@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院临泽内陆河流域研究站，兰州", "country": "中国" }, { "true_name": "赵文智", "email": "zhaowzh@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "ds_meta_authors": [ { "true_name": "张格非", "email": "zhanggf@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院临泽内陆河流域研究站，兰州", "country": "中国" } ], "ds_managers": [ { "true_name": "赵文智", "email": "zhaowzh@lzb.ac.cn", "work_for": "中国科学院西北生态环境资源研究院", "country": "中国" } ], "category": "沙漠与荒漠化" }