Ecophysiological and floristic study of the lichen communities in Livingston Island

Scientific objectives:-Floristic study of Livingston Island.-Structure, succession and dynamism of the principal lichen and bryolichen communities.-Chorological study (distribution) in the Juan Carlos I base area of plantspecies with special bioclimatic significance.-Research on the early development of lichen symbiosis in relation tomicroclimate and different rock types.-Colonization and adaptation strategies of lichens in the Antarctic environment.Activities carried out:The Byers Peninsula was explored. In this extensive ice-free region, a largenumber of samples were collected on acid to ultrabasic rocks, both eruptive andsedimentary. The following places were visited:1) Beach and front moraine of Roch Dome;2) Clark Nunatak and coastal cliffs up to Elephant Point;3) NE end in the north coast of the peninsula;4) Interior uplands and Chester Cone;5) Cerro Negro and surrounding area;6) SW coast, including exploration of sedimentary rocks.Approximately 300 samples of lichens and mosses were collected, with specialattention to nitrophilous and ornithocoprophilous flora and the floraassociated with gelifraction phenomena. A cartographic survey of Umbilicaria antarctica, Usnea antarctica and Parmelia saxatilis was carried out on thesouth coast in order to check the possible E-W xericity gradient.The ice-freeregion of Hurd Peninsula and north of False Bay were explored, and an abundance of Ramalina terebrata was noted, a species unknown in the area around the Juan Carlos I base. Macrolichens unknown to occur in Antarctica were discovered andcollected near the summit of Monte Reina Sofia. The lichens could be Umbilicaria krascheninikovi, a relatively common lichen in the Andes.A detailedstudy was made of the communities associated with an extreme supply ofnutrients, particularly the so-called ornithocoprophilous communities typicalof places frequently visited by birds. It was noted that Caloplaca regalis, soabundant in other parts of the South Shetland Islands, was almost totallyabsent from these communities. With regards to the structural and dynamics aspect, the model chosen was the bryolichen communities, where competition forspace is strongest, with various strategies and forms of growth sharing a smallarea, including the epiphytic and parasitic. Small plots were described and photographed with their evolution to be measured and marked in subsequent years.In collaboration with the team of geomorphologists, an initial approach was made to the dating of recent moraines and beaches on the basis of the study ofthe succession of lichen communities. The site chosen for this study was theglacier front on the western slope of the Monte Reina Sofia and the area of beach terraces at the Juan Carlos I base. A distribution map was produced at 1:5000 scale of the species of phanerogams Colobanthus quitensis and Deschampsia antarctica, and of the lichens Sphaerophorus globosus, Placopsis contortuplicata, Himantormia lugubris, Umbilicaria aprima, U. decussata, U.nylanderina and U. antarctica. The bioindicator value taken for each of these species is as follows:1)Termophytic specie: C. quitensis, D. antarctica, Sph. Globosus;2)Cryophytic species: Pl. contortuplicata, H. Lugubris;3)Aerohygrophytic species: U. aprima, U.decussata, U. nylanderiana;4)Substratohygrophitic species: U. antarctica.The initial development of the lichen symbiosis was commenced in natural condition, and consisted in the cultivation of lichen samples in naturalstations. Five different species of lichen were selected, 4 of them with awell-characterized ecological behaviour:-Usnea aurantico-atra (spores);-Usnea antarctica (soredia);-Parmelia saxatilis (isidia);-Umbilicaria decussata (thallospores);-Himantormia lugubris (spores).The experiment will run 5 years and samples will be taken every year.Samples were collected for analysis at the University of Kiel. Twenty specimens were collected of the following species: Pseudephebe pubescens,Parmalia saxatilis, Ramalina terebrata, Placopsis contortuplicata, Umbilicaria decussata, Coloplaca sublobulata, Haematomma erythromm, Lecidea sciatrapha,Usnea antarctica, Usnea aurantico-atra, Umbilicaria antarctica.

科学研究目标：
- 开展利文斯顿岛（Livingston Island）的植物区系研究。
- 探究主要地衣与苔藓地衣群落的结构、演替及动态变化。
- 针对胡安·卡洛斯一世（Juan Carlos I）基地周边区域内具有特殊生物气候意义的植物物种开展分布区研究（chorological study）。
- 研究与微气候（microclimate）及不同岩石类型相关的地衣共生体早期发育过程。
- 探究南极环境中地衣的定殖与适应策略。

开展的研究工作：
考察了拜尔斯半岛（Byers Peninsula）——这片广阔的无冰区域，研究人员在火成岩与沉积岩等酸性至超基性岩上采集了大量样本。先后到访以下区域：
1. 罗什穹丘（Roch Dome）海滩与前缘冰碛；
2. 克拉克冰原岛峰（Clark Nunatak）及延伸至象点（Elephant Point）的海岸悬崖；
3. 半岛北海岸的东北端；
4. 内陆高地与切斯特锥（Chester Cone）；
5. 塞罗内格罗山（Cerro Negro）及其周边区域；
6. 西南海岸，包括沉积岩勘探区域。

共采集约300份地衣与苔藓样本，重点关注嗜氮植物、鸟嗜植物以及与冻融崩解现象相关的植被。在南海岸开展了南极脐衣（Umbilicaria antarctica）、南极松萝（Usnea antarctica）与石梅衣（Parmelia saxatilis）的制图调查，以验证东西向干旱梯度的存在性。

考察了赫德半岛（Hurd Peninsula）以及福尔斯湾（False Bay）以北的无冰区域，发现并记录了大量在胡安·卡洛斯一世基地周边此前未被记录的钻形枝状地衣（Ramalina terebrata）。在雷纳索菲亚山（Monte Reina Sofia）峰顶附近发现并采集了此前南极地区未见记载的大型地衣，经初步鉴定可能为安第斯山脉较为常见的克氏脐衣（Umbilicaria krascheninikovi）。

针对极端营养供给环境下的群落开展了详细研究，尤其是鸟类频繁活动区域典型的鸟嗜群落。研究发现，在南设得兰群岛其他区域极为常见的帝王黄鳞叶衣（Caloplaca regalis）几乎未出现在此类群落中。

在结构与动态研究方面，选取空间竞争最为激烈的苔藓地衣群落作为研究模型，多种生长策略与生长型共享狭小空间，包括附生与寄生类型。对小型样地进行了描述与拍照，以便后续多年监测并记录其演替过程。

与地貌学家团队合作，基于地衣群落的演替序列，首次对近期冰碛与海滩开展年代学初步研究。本次研究选取的点位为雷纳索菲亚山西坡的冰川前缘，以及胡安·卡洛斯一世基地的海滩阶地区域。

编制了比例尺为1:5000的分布图，涵盖显花植物漆姑草（Colobanthus quitensis）与南极发草（Deschampsia antarctica），以及地衣类的球枝地衣（Sphaerophorus globosus）、扭卷盘腹叶衣（Placopsis contortuplicata）、垂悬膜地衣（Himantormia lugubris）、厚脐乌芝（Umbilicaria aprima）、十字脐衣（Umbilicaria decussata）、尼氏脐衣（Umbilicaria nylanderina）与南极脐衣（Umbilicaria antarctica）。

上述各物种的生物指示价值分类如下：
1) 适温物种：C. quitensis、D. antarctica、Sph. globosus；
2) 适寒物种：Pl. contortuplicata、H. lugubris；
3) 气生湿生物种：U. aprima、U. decussata、U. nylanderiana；
4) 基质湿生物种：U. antarctica。

启动了自然条件下地衣共生体早期发育的研究工作，具体为在原生境中培育地衣样本。共选取5种不同的地衣物种，其中4种已明确其生态特征：
- 橙黑松萝（Usnea aurantico-atra）（孢子繁殖）；
- 南极松萝（Usnea antarctica）（粉芽（soredia）繁殖）；
- 石梅衣（Parmelia saxatilis）（裂芽（isidia）繁殖）；
- 十字脐衣（Umbilicaria decussata）（叶状体孢子（thallospores）繁殖）；
- 垂悬膜地衣（Himantormia lugubris）（孢子繁殖）。

该实验周期为5年，每年将采集样本用于分析。

在基尔大学（University of Kiel）开展分析所需的样本采集工作。共采集以下11个物种的20份标本：短绒毛假白发藓（Pseudephebe pubescens）、石梅衣（Parmelia saxatilis）、钻形枝状地衣（Ramalina terebrata）、扭卷盘腹叶衣（Placopsis contortuplicata）、十字脐衣（Umbilicaria decussata）、亚叶黄鳞叶衣（Coloplaca sublobulata）、红脉血盘衣（Haematomma erythromm）、暗边鳞盾（Lecidea sciatrapha）、南极松萝（Usnea antarctica）、橙黑松萝（Usnea aurantico-atra）、南极脐衣（Umbilicaria antarctica）。