著：（巴西）卡米拉·戈梅斯·圣安娜 譯：龍林格格 校：李夢一欣

面對氣候變化與流行性疾病日益顯著的影響，景觀被認(rèn)為是能夠構(gòu)建可持續(xù)城市發(fā)展的基礎(chǔ)設(shè)施，它將土地利用與地區(qū)自然發(fā)展、生物和非生物特征以及其文化、美學(xué)和遺產(chǎn)表現(xiàn)形式聯(lián)系在一起[1]。

北美風(fēng)景園林師弗雷德里克·勞·奧姆斯特德（1822—1903）在其先驅(qū)性設(shè)計方法中指出，可通過闡明景觀的基礎(chǔ)設(shè)施問題來實現(xiàn)規(guī)劃和設(shè)計功能。他用技術(shù)性的方法回應(yīng)了城市需求（城市化和自然資源相協(xié)調(diào)），同時也提升了城市景觀的生態(tài)、美學(xué)、社會和文化價值[1-2]。因此，對于城市邊緣景觀而言，藍(lán)綠開放空間作為整體形成了一個景觀系統(tǒng)，而不再是一個孤立的要素[1-7]。

2022年是奧姆斯特德200周年誕辰，為了紀(jì)念他，許多機構(gòu)組織了各類討論、展覽和會議，例如“現(xiàn)在的奧姆斯特德”（olmstednow.org/）線上展覽討論了奧姆斯特德對于建設(shè)更好城市做出的重要貢獻。在當(dāng)代范式下重新審視奧姆斯特德的實踐，是應(yīng)對氣候變化影響的基礎(chǔ)[1]。在此背景下，考慮到西班牙最近有關(guān)構(gòu)建城市藍(lán)綠空間網(wǎng)絡(luò)的建議，“翡翠與藍(lán)寶石項鏈”是實施多尺度綠色基礎(chǔ)設(shè)施策略的案例，其將藍(lán)綠系統(tǒng)納入同一個網(wǎng)絡(luò)，促進了自然、社會和生產(chǎn)過程，并與區(qū)域的建筑基礎(chǔ)設(shè)施相結(jié)合[8]，保證了生物多樣性和公共健康[9]。

綠色基礎(chǔ)設(shè)施（GI）已經(jīng)成為規(guī)劃和設(shè)計復(fù)雜景觀的綜合策略。然而，GI對于整合邊緣景觀中的廢棄地、缺乏基礎(chǔ)設(shè)施的場地和（或）棕地等區(qū)域邊緣地區(qū)的能力還沒有獲得過多探索。邊緣景觀存在于邊緣區(qū)域及其社區(qū)，是評估區(qū)域城市發(fā)展模式的至關(guān)重要的空間。傳統(tǒng)意義上，邊緣景觀的建設(shè)往往忽略當(dāng)?shù)氐淖匀慌c文化，也忽視居住在此的人群。人們更加關(guān)注能夠促進城市旅游和遺產(chǎn)的景觀，這些景觀因其遺產(chǎn)、經(jīng)濟和文化特點而被認(rèn)可。

事實上，不能簡單地以缺失和排斥為特征，從否定主義的角度理解邊緣地區(qū)，而是應(yīng)該基于邊緣地區(qū)對設(shè)計公平城市藍(lán)綠空間的作用，結(jié)合彈性和教育的特征，將它們理解為異質(zhì)性、生物多樣性和動態(tài)的空間[10]，將城市內(nèi)部、邊緣和外部的生產(chǎn)性景觀結(jié)合起來。

筆者以西班牙維多利亞-加斯蒂茲為案例，對如何規(guī)劃和設(shè)計“翡翠與藍(lán)寶石項鏈”開展研究，以此闡釋奧姆斯特德理論中提出的邊緣景觀的重要性。

1 波士頓奧姆斯特德翡翠項鏈的邊緣景觀

在波士頓翡翠項鏈（1878—1880年）的綠色開放空間方案中，奧姆斯特德與他的合作者查爾斯·艾略特（1859—1957）鞏固了綠色開放空間系統(tǒng)的想法，使其在土地利用規(guī)劃中成為關(guān)鍵基礎(chǔ)設(shè)施。這些綠色開放空間從區(qū)域到地方，在不同尺度上銜接了當(dāng)?shù)氐乃h(huán)境、生態(tài)空間、娛樂空間和交通系統(tǒng)[1,6,11]。

基于這一想法，他們創(chuàng)造了一個綠色空間系統(tǒng)——由公園大道（也被稱為公園路）將波士頓公園和富蘭克林公園連接起來[12]。這個系統(tǒng)使公共空間重新恢復(fù)活力，并將邊緣景觀與城市的其他區(qū)域連接起來，確保了這些適于漫步和通行的大道的連接性和質(zhì)量，并重新建立了水與城市綠地系統(tǒng)的關(guān)系。

1.1 奧姆斯特德波士頓方案中的藍(lán)寶石項鏈

奧姆斯特德波士頓方案中的水系統(tǒng)——“藍(lán)寶石項鏈”，在連接邊緣景觀上發(fā)揮著重要且彈性的作用。例如受潮汐、渾河和查爾斯河洪水影響的后灣沼澤區(qū)，其在技術(shù)上響應(yīng)了調(diào)節(jié)水文循環(huán)的需求，種植了能夠耐受該地區(qū)咸水的植物[3]。在方案中，奧姆斯特德創(chuàng)造了一種來源于繪畫和自然主義美學(xué)靈感的有機設(shè)計方法，盡管深受浪漫主義影響，但他用較少的元素探索了物種的季節(jié)性和恢復(fù)力[12]。

景觀策略在綠色和多功能基礎(chǔ)設(shè)施解決方案的基礎(chǔ)上，創(chuàng)造了一個靠近自然與社區(qū)并融入了邊緣地區(qū)的波士頓河畔。因此，奧姆斯特德對藍(lán)綠開放系統(tǒng)的貢獻被認(rèn)為是綠色基礎(chǔ)設(shè)施策略的奠基思想，即GI以邊緣景觀為基礎(chǔ)，成為今天重新探討城市景觀規(guī)劃和設(shè)計的一種方式。

1.2 維多利亞-加斯蒂茲的綠色基礎(chǔ)設(shè)施策略和“翡翠與藍(lán)寶石項鏈”

維多利亞-加斯蒂茲是西班牙巴斯克自治區(qū)的首府，是該地區(qū)最大、布局最緊湊的城市，占地276.08 km2，擁有253 093名居民[13]。支撐維多利亞-加斯蒂茲的城市綠色基礎(chǔ)設(shè)施網(wǎng)絡(luò)的方法策略確定于2013年。在這里，綠色基礎(chǔ)設(shè)施作為一個“戰(zhàn)略性規(guī)劃的自然、鄉(xiāng)村和城市綠地網(wǎng)絡(luò)（包括河流及其他形式的水系），提供廣泛的社會生態(tài)系統(tǒng)服務(wù)，推動環(huán)境、社會和經(jīng)濟效益，并促進城市居民的健康”[5]。

GI策略是為了促進城市的復(fù)興，與保護生物多樣性和氣候變化計劃形成對話，以強化對維多利亞-加斯蒂茲2012年歐洲綠色之都的認(rèn)可（圖1）?！棒浯渑c藍(lán)寶石項鏈”方案旨在將維多利亞-加斯蒂茲1/3的區(qū)域轉(zhuǎn)化成公共空間，為居民創(chuàng)造人均45 m2的綠色區(qū)域[14]。

1 維多利亞-加斯蒂茲的綠色之都標(biāo)志Vitoria-Gasteiz green capital symbol

在西班牙，每個自治區(qū)都有3年的時間根據(jù)歐盟委員會相關(guān)導(dǎo)則《綠色基礎(chǔ)設(shè)施——提升歐洲的自然資本》（2013年）來制定自適性綠色基礎(chǔ)設(shè)施策略。西班牙第33/2015號法律涉及自然遺產(chǎn)和生物多樣性保護，并借鑒歐洲關(guān)于GI的法律，幫助實施綠色基礎(chǔ)設(shè)施與生態(tài)連接、修復(fù)的國家戰(zhàn)略。然而，上述導(dǎo)則側(cè)重于介紹GI的概念、原則及組成要素，并未提供一個針對地方的多尺度和多功能方法。

在Tojo[15]看來，西班牙的GI策略有一個共同點是將基礎(chǔ)設(shè)施作為生態(tài)網(wǎng)絡(luò)與城市系統(tǒng)間的一個連接要素。這正是維多利亞-加斯蒂茲地區(qū)及其綠色基礎(chǔ)設(shè)施系統(tǒng)的情況，“其被定義的前提是，如果將城市綠地中包含的自然與半自然空間整合到同一個系統(tǒng)中并得到系統(tǒng)的管理時，會帶來更大的效益”[13]。

1.3 維多利亞-加斯蒂茲的綠色基礎(chǔ)設(shè)施的方法性策略：重新考慮邊緣景觀

維多利亞-加斯蒂茲的綠色基礎(chǔ)設(shè)施規(guī)劃和設(shè)計所采用的方法性策略回應(yīng)了奧姆斯特德理論。該策略創(chuàng)造了區(qū)域的分層解讀方法，以便于理解景觀作為基礎(chǔ)設(shè)施在一個GI區(qū)域網(wǎng)絡(luò)的結(jié)構(gòu)。先從邊緣區(qū)域開始，試圖分析該城市在阿拉瓦中央生物區(qū)的融入及生態(tài)問題。維多利亞-加斯蒂茲是坎塔布連山-比利牛斯山脈-法國中央高原-西阿爾卑斯山這一宏偉生態(tài)走廊中最突出的生物多樣性保護區(qū)之一；同時，它也在伊比利亞半島北部地區(qū)和泛歐洲生態(tài)網(wǎng)絡(luò)方面發(fā)揮著主導(dǎo)作用。

通過疊加各類地圖來確定該地區(qū)藍(lán)綠空間的特征，并以此在景觀設(shè)計中整合邊緣區(qū)域。區(qū)域尺度上，景觀基礎(chǔ)設(shè)施規(guī)劃和設(shè)計考慮了具有環(huán)境效益的保護空間網(wǎng)絡(luò)、自然公園、受保護的群落生境、具有重要遺產(chǎn)意義的喬木類型、歐洲自然保護區(qū)網(wǎng)絡(luò)（Natura 2000）、《拉姆薩爾公約》中的濕地保護區(qū)網(wǎng)絡(luò)、阿拉瓦生物區(qū)目錄中的獨特景觀單元網(wǎng)絡(luò)以及領(lǐng)土環(huán)境保護區(qū)域。地方尺度上，確定了翡翠與藍(lán)寶石項鏈藍(lán)綠空間的構(gòu)成元素，包括公園、花園、墓地、綠地、森林、灌木叢、草地、農(nóng)田、菜地、濕地、河流、溪流及其他計劃發(fā)展用地（圖2）。

2 維多利亞-加斯蒂茲的邊緣綠帶Marginal green belt in Vitoria-Gasteiz

筆者根據(jù)分析的結(jié)果，確定了這一緊湊城市在平原邊緣景觀中的作用。為了遏制城市的擴張，1995年在邊緣景觀中建設(shè)了綠帶和農(nóng)業(yè)帶，并通過建設(shè)GI來恢復(fù)生態(tài)退化區(qū)域（圖3），在這里，邊緣地區(qū)做出了必不可少的貢獻。

3 邊緣農(nóng)業(yè)帶The marginal agriculture belt

接下來，建立城市分層解讀體系，解析與水網(wǎng)（包括地下水、河流、溪流、堤壩、濕地和下水管網(wǎng)）有關(guān)的城市基礎(chǔ)設(shè)施、綠帶中具有環(huán)境效益的公園及城市綠色斑塊之間的關(guān)系。此外，在綠地和城市地塊中還包括主要位于邊緣地帶的以空置、廢棄和（或）棕地為特征的零散區(qū)域。然后，將上述各類元素疊加在一起，并添加其他信息，如農(nóng)業(yè)帶、公共游覽路徑（小徑、步行道等）和可持續(xù)的移動基礎(chǔ)設(shè)施。通過建設(shè)城市步行景觀、生態(tài)路線以及綠帶步行游覽路線，使物理層面和生態(tài)層面的遷移都變得更加容易，從而促進系統(tǒng)中邊緣地帶的連接度（圖4）。

4 藍(lán)綠空間系統(tǒng)The blue-green space system

2 維多利亞-加斯蒂茲邊緣地區(qū)的翡翠與藍(lán)寶石項鏈策略

GI策略確定了現(xiàn)有的基礎(chǔ)設(shè)施網(wǎng)絡(luò)與區(qū)域物理、生態(tài)和文化聯(lián)系的關(guān)系，并定義了一個將核心要素、節(jié)點元素和連接線集合在一起的藍(lán)綠系統(tǒng)網(wǎng)絡(luò)。生態(tài)觀點通過汲取景觀生態(tài)學(xué)理論[16-19]原則被深化。在此基礎(chǔ)上，使用以下術(shù)語：1）核心要素，是指在毗鄰城市的區(qū)域，具有高度的自然性和處于充分保護狀態(tài)的空間；2）節(jié)點，位于城市內(nèi)的綠色空間，由于其規(guī)模和位置，可代表城市綠地系統(tǒng)的基本組成部分；3）連接線，具有線性性質(zhì)的景觀元素，主要功能是加強核心要素和節(jié)點之間的連接[14]。

維多利亞-加斯蒂茲的邊緣綠帶、農(nóng)業(yè)帶的核心要素為“總面積為1 016 hm2的環(huán)境效益區(qū)（889 hm2為城郊公園，127 hm2為農(nóng)業(yè)區(qū)）”[14]。其中，公園、廣場、花園和草地是展現(xiàn)環(huán)境特征的節(jié)點，占據(jù)著城市外圍和中心區(qū)域，具有邊緣地區(qū)濱河景觀的特征。

大多數(shù)節(jié)點是被定義和劃定出來的空間，一般依據(jù)其重要性分為主要節(jié)點和次要節(jié)點。擴散在各處的場所空間可以作為建筑元素，承載某種使用類型，例如立體綠化和屋頂綠化。連接線是銜接節(jié)點和核心元素的線性元素，它包含傳統(tǒng)的綠廊和水系，連接邊緣地區(qū)內(nèi)部以及邊緣與區(qū)域中心。主要的連接策略包括組織東西連接線、南北水系連接線和南北非水系連接線（圖5）。

5 由核心要素、節(jié)點元素和連接線組成的生態(tài)系統(tǒng)The definition of an ecological system that articulates core elements, node elements and connectors

今天重新討論奧姆斯特德理論，形成了一種系統(tǒng)地理解生態(tài)過程和其他基礎(chǔ)設(shè)施的方法。景觀作為一種基礎(chǔ)設(shè)施，被從多維尺度（不同的基礎(chǔ)設(shè)施、時間性、連接性和功能性）來規(guī)劃和設(shè)計，以適應(yīng)氣候變化和保護生物多樣性的城市。在這種情況下，重塑策略定義了一條“藍(lán)綠項鏈”，不同于傳統(tǒng)的規(guī)劃和設(shè)計，它關(guān)注邊緣區(qū)域。由此，邊緣地區(qū)成為主角，強化了綠帶和農(nóng)業(yè)帶的當(dāng)代價值。

2.1 翡翠與藍(lán)寶石項鏈：公園在邊緣區(qū)域的作用

維多利亞-加斯蒂茲的邊緣區(qū)域存在一些公園，包括扎巴爾加納公園（圖6）、扎多拉公園（圖7）、奧拉里祖公園（圖8）、薩爾布魯阿濕地公園（圖9）和亞門蒂亞公園（圖10）。它們在生態(tài)網(wǎng)絡(luò)和水網(wǎng)中發(fā)揮著核心要素的作用，或與綠帶和農(nóng)業(yè)帶呼應(yīng)，或與開放空間系統(tǒng)相連，使人們能夠參觀城市主要的遺產(chǎn)景觀。同時，公園中還展示了鄉(xiāng)村景觀，促使人們重新思考社區(qū)與城市邊緣及其濱河景觀的關(guān)系。

6 扎巴爾加納公園Zabalgana park

7 扎多拉公園Zadorra park

8 奧拉里祖公園Olarizu park

9 薩爾布魯阿濕地公園Humedales de Salburua park

10 亞門蒂亞公園Armentia park

正如奧姆斯特德的策略中，水系這條“藍(lán)寶石項鏈”在邊緣區(qū)域景觀設(shè)計中扮演了一個主導(dǎo)和彈性的角色，有助于從技術(shù)和美學(xué)角度建構(gòu)公園系統(tǒng)。同時，也促進了區(qū)域內(nèi)物理與生態(tài)上的聯(lián)系。

2.2 從民主層面重新思考邊緣地區(qū)

從民主層面來看，對于維多利亞-加斯蒂茲而言，奧姆斯特德提出的藍(lán)綠空間系統(tǒng)不僅實現(xiàn)于公園中，還應(yīng)用于步行和騎行的綠色路徑中，這些路徑讓城市居民有更多機會接觸這些空間和其承載的項目（如奧拉里祖植物園，阿塔利亞自然濕地中心等）；其主要目標(biāo)之一是“促進與綠色空間兼容的公共使用方式，增加休閑和娛樂的機會，提高可達(dá)性以及州與城市的聯(lián)系，保護文化遺產(chǎn)和傳統(tǒng)景觀，增強地方認(rèn)同感和歸屬感”[14]。

社區(qū)通過組織研討會、講座和展覽等實現(xiàn)奧姆斯特德理論的創(chuàng)新，加強了其從項目開始到結(jié)束的參與度。如在區(qū)域內(nèi)開展“認(rèn)領(lǐng)一棵樹”種植活動、建造家庭花園、學(xué)校及城市花園等項目，提高人們對邊緣景觀中綠色基礎(chǔ)設(shè)施網(wǎng)絡(luò)及藍(lán)綠空間作用的認(rèn)識。此外，還有制定生物多樣性清單、邀請社區(qū)人群采用自行車或步行的方式游覽或免費參觀邊緣區(qū)域等方式。

3 邊緣地區(qū)的翡翠與藍(lán)寶石項鏈：扎多拉公園項目

重新研究奧姆斯特德理論并結(jié)合景觀生態(tài)學(xué)理論，可以看出綠色基礎(chǔ)設(shè)施是基于藍(lán)綠系統(tǒng)的整體利益來定義的，但其中的每個要素都很重要。扎多拉河是維多利亞-加斯蒂茲市的主要河流，從區(qū)域?qū)用婵?，由于其生物多樣性高度集中，它成為歐洲自然保護區(qū)網(wǎng)絡(luò)的組成部分。扎多拉公園位于城市北部地區(qū)，沿其13 km的線性公園限制了城市向北擴張，構(gòu)成了城市的綠帶。到目前為止，這個線性公園只有2個區(qū)段得到了實施。

3.1 以農(nóng)業(yè)區(qū)與濱水區(qū)連接城市與鄉(xiāng)村不同規(guī)模的邊緣景觀

綠道、自行車道和小徑將公園與周圍環(huán)境連接起來，主要是與該地區(qū)的農(nóng)業(yè)區(qū)相連。該項目尋求從城市到鄉(xiāng)村景觀的過渡，以綠帶，尤其是以具有較高生態(tài)價值和具有歷史、藝術(shù)意義的農(nóng)業(yè)區(qū)來突出綠色開放空間系統(tǒng)的作用。

在邊緣景觀的生態(tài)設(shè)計中，可食用植物景觀和水景占據(jù)了突出地位，并使用具有韌性的本地物種，滲透著自然主義原則。這些最細(xì)微的要素幫助使用者識別場地的植被結(jié)構(gòu)，且只需要少量維護。植物類型的選擇也受制于當(dāng)前的水量情況，由于該地區(qū)面臨嚴(yán)重的水災(zāi)問題，因此當(dāng)?shù)靥岢鼋ㄔO(shè)一個可持續(xù)的排水系統(tǒng)，以優(yōu)化排水性能，效仿奧姆斯特德的實踐。

3.2 利用廢棄的區(qū)域與低價值的植物展現(xiàn)邊緣景觀的野性

奧姆斯特德在景觀中人為地創(chuàng)造了一種野性美學(xué)，將這種美學(xué)特征融入城市天際線或許可以使整個社區(qū)更接近自然，并促使每個空間使用者都可以感知這一天際線下的荒野景觀[3-4]。在維多利亞-加斯蒂茲地區(qū)，藍(lán)綠空間也成為重新思考區(qū)域邊緣化、退化以及無人居住地區(qū)的一種方式，其通過恢復(fù)生態(tài)、種植本地物種、創(chuàng)造不同的棲息地、提高復(fù)原力和生物多樣性，在人類和自然-文化之間的互動中逐步實現(xiàn)了過渡（圖11）。

11 位于戈莫拉區(qū)的扎多拉公園Zadorra park at the Gomorra Section

這一理念已經(jīng)被應(yīng)用在城市的生態(tài)和社會文化網(wǎng)絡(luò)設(shè)計上，通過營造更多具有自然植被的地貌，展現(xiàn)場所的動態(tài)變化，使場所更易于管理并得到社區(qū)認(rèn)可。這一過程展現(xiàn)了人們因城市的過度建設(shè)，正在失去對自然的體驗。而在不同的時間和條件下，奧姆斯特德重視并努力恢復(fù)這種體驗。

邊緣地區(qū)涉及農(nóng)業(yè)區(qū)、濱水地帶、廢棄地區(qū)和利用價值較低的植物。邊緣景觀作為主角，從物理上、生態(tài)上和美學(xué)上將邊緣區(qū)域聯(lián)系起來。除了從綠帶到公園的多尺度GI規(guī)劃和設(shè)計建議，在重新探求奧姆斯特德理論的今天，區(qū)域中的不同社區(qū)也成為景觀的一部分，并成為景觀建設(shè)的主力軍[20]。

4 總結(jié)

重新審視奧姆斯特德的翡翠項鏈理論是研究景觀作為城市可持續(xù)發(fā)展基礎(chǔ)設(shè)施的根本，尤其是在我們面對解決氣候變化和生物多樣性匱乏的問題時。在這一背景下，在GI策略與項目中定義了藍(lán)綠開放空間系統(tǒng)，體現(xiàn)了在多種尺度中景觀不同層面的特征。

當(dāng)從第一次解讀項目開始并建立方法性戰(zhàn)略時，這種多尺度的維度就體現(xiàn)出來了。人們試圖基于生態(tài)、美學(xué)、社會和文化價值等維度來理解區(qū)域空間，通過整合各類地圖和信息來確定立意，然后轉(zhuǎn)化為項目的形式。

維多利亞-加斯蒂茲的景觀基礎(chǔ)設(shè)施的總體設(shè)計以景觀生態(tài)學(xué)理論為前提，特別關(guān)注通過加強物理和生態(tài)連接促進生物多樣性，從而達(dá)到降低該地區(qū)綠色區(qū)域破碎化程度的目的。通過這種方式，發(fā)展出了由核心要素、節(jié)點元素和連接線組成的生態(tài)網(wǎng)絡(luò)。識別當(dāng)?shù)氐乃{(lán)綠空間系統(tǒng)要素，并按照其在生態(tài)網(wǎng)絡(luò)中的重要性，以核心要素、節(jié)點元素和連接線的方式組織起來，總體設(shè)計加強了對“翡翠”——綠色空間和“藍(lán)寶石”——水系的理解。

在地方尺度，其想法是利用生態(tài)環(huán)境修復(fù)，用本地物種和基于自然的解決方案拉近自然和人類的距離。這為奧姆斯特德將野生環(huán)境與城市結(jié)合起來的思想提供了一個現(xiàn)代視角。在基于自然的解決方案和現(xiàn)代技術(shù)的基礎(chǔ)上創(chuàng)造了一個人工系統(tǒng)結(jié)構(gòu)，這很有可能促使社區(qū)人群在水的引導(dǎo)下去感知和改造他們的邊緣景觀。正如奧姆斯特德的實踐，維多利亞-加斯蒂茲尤為注意為邊緣區(qū)域的濱河景觀提供技術(shù)性和藝術(shù)化的解決方案。同波士頓翡翠項鏈一樣，這里的藍(lán)綠空間系統(tǒng)將重點放在邊緣空間對區(qū)域翡翠和藍(lán)寶石項鏈的作用上，并重視已有的綠帶和農(nóng)業(yè)帶。

從城市邊緣景觀的角度來考慮城市景觀規(guī)劃，還可以增強城市與鄉(xiāng)村的連接度，修正區(qū)域中生產(chǎn)性景觀的下降趨勢，并糾正將鄉(xiāng)村視作與自然無關(guān)的生產(chǎn)區(qū)的誤解。生產(chǎn)性景觀被有效地理解并納入不同的尺度中，例如給公園提供觀賞農(nóng)業(yè)區(qū)的絕佳視野，或加入鄉(xiāng)間小徑、城市花園和家庭花園等元素中。

維多利亞-加斯蒂茲的“翡翠與藍(lán)寶石項鏈”為反思如今傳統(tǒng)的規(guī)劃設(shè)計實踐提供了借鑒和參考，讓邊緣景觀成為策略的驅(qū)動力，并納入城市規(guī)劃設(shè)計。邊緣景觀在構(gòu)建綠帶、農(nóng)業(yè)帶、水網(wǎng)和其他綠色軸線方面舉足輕重，在物理和生態(tài)層面連接了藍(lán)綠空間系統(tǒng)；而在生態(tài)與社會文化層面則考慮了對該地區(qū)未來的決策，并做了大量的工作來提高社區(qū)對景觀的認(rèn)知，如營造步行景觀和認(rèn)養(yǎng)樹木活動。社區(qū)不僅能感知景觀，也成為景觀的一部分，保障了其對景觀的權(quán)利，延續(xù)奧姆斯特德提出的公園民主價值。

值得指出的是，目前全球有29%的城市人口住在貧民窟[21]，且有大部分人生活在郊區(qū)，這與維多利亞-加斯提茲的情況完全不同，他們?nèi)狈Τ鞘谢A(chǔ)設(shè)施和公平權(quán)利的保障。同時，郊區(qū)是《巴黎協(xié)定》和《生物多樣性公約》嘗試保護的環(huán)境利益區(qū)。因此，這一經(jīng)驗可以為其他國家提供靈感，以地方性的方法重新研究邊緣地區(qū)，并更新和再次思索今天的奧姆斯特德理論。

圖片來源：

圖1、6～11?卡米拉·戈梅斯·圣安娜；圖2～5?卡羅琳·費爾南德斯，來源于https://www.vitoria-gasteiz.org/j34-01w/catalogo/portada?idioma=es。

（編輯/李清清）

Contribution of Blue-Green Space System in Marginal Landscape: A Case Study of the “Emerald and Sapphire Necklace” in Vitoria-Gasteiz, Spain

Author: (BRA) Camila Gomes Sant’Anna Translator: LONG Lingege Proofreader: LI Mengyixin

Facing the increasingly significant impacts of climate change and the pandemic, the landscape is understood as the infrastructure capable of structuring sustainable urban development that brings together land use in line with the natural processes of the place, its biotic and abiotic characteristics and its cultural, aesthetic and heritage expressions[1].

In the pioneering approach of the North American landscape architect Frederick Law Olmsted(1822-1903), planning and design function by articulating the infrastructural issues of the landscape.They bring up technical answers to the demands of the city (urbanization and natural resources),as well as promote ecological, aesthetic, social and cultural values[1-2]. Therefore, green and blue open spaces are understood as a whole, considering the marginal landscape, forming a system that frames the landscape, no longer as an isolated element[1-7].

This year is the celebration of Olmsted’s Bicentennial. Therefore, many institutions are organizing debates, exhibitions and conferences,for example, the initiative “Olmsted Now”(olmstednow.org/), to debate the most significant contribution Olmsted made to building better cities.Rethinking Olmsted’s practice, under contemporary paradigms, emerges as fundamental to facing the impact of climate change[1]. Within this context,considering recent Spain proposals for urban blue-green spaces networks, the “emerald and sapphire necklaces” are examples of multi-scale green infrastructure strategies. They include the green and blue systems in a network that promotes natural, social and productive processes, integrating with the built infrastructures of the territory[8]to guarantee biodiversity and public health[9].

Green infrastructure (GI) has already become consolidated as a strategy to plan and design the landscape in its complexity. However, there has not been much exploration of its ability to integrate the territory’s peripheral areas, embracing its obsolete areas, lacking infrastructure and/or brownfields,which are present in its marginal landscapes. The marginal landscape exists in peripheral territories and their communities, which are essential spaces for reviewing the territory’s urban development paradigm, which has traditionally disregarded nature and culture and, often, the population that inhabits it. There has also been a greater focus on promoting city touristic and heritage landscapes, understood as those recognized for their heritage and economic and cultural characteristics.

The issue involves not simply understanding these margins from a negationist perspective,marked by absence and exclusion, but rather understanding them as heterogeneous, biodiverse and dynamic spaces[10]based on their contribution to the design of equitable urban blue and green spaces, resilient and educational, which bring together the productive landscapes inside, on the margins and outside the cities.

Having carried out the study to understand how to plan and design “sapphire and emerald necklaces”in the case study of Vitoria-Gasteiz in Spain demonstrates the importance of considering marginal landscapes as introduced in Olmsted’s theory.

1 The Marginal Landscape at the Boston Olmsted Emerald Necklace

In Boston, in the proposal for green open spaces, known as the Emerald Necklace (1878-1880), Olmsted and his collaborator Charles Eliot(1859-1957) consolidated the idea of a green open space system that works as key infrastructure in the design of the land use. These green open spaces articulated aquatic, ecological, recreational and transport systems at different scales of the territory, from regional to local[1,6,11].

Based on this idea, a green-space system was created, structured by park avenues—known as parkway, that link Boston Common with Franklin Park[12]. This system renatured spaces and joined the marginal landscape with the city’s other areas,ensuring the connection and quality of these avenues, suitable for strolling and promenading,reestablished a new relationship with the water and green space systems of the city.

1.1 The Sapphire Necklace in Olmsted’s Boston Proposal

The water system, “sapphire necklace”, in Olmsted’s Boston proposal has an important and resilient role in connecting marginal landscapes.In the Back Bay swamp area, for example, it technically responds to the need to regulate the hydrological cycle, associated with the planting of species resistant to the brackishness of the territory, visited by the tides and subject to the floods of the Muddy River and the Charles River[3].In his proposal, Olmsted developed an organic design inspired by painting and naturalist aesthetics;although still very influenced by the Pittoresque vision, he explored the seasonality and resilience of species using few built the elements[12].

This landscape strategy created a Boston riverside incorporated the margins, based on green and multifunctional infrastructure solutions, that approximated nature and community. Therefore,Olmsted’s contributions to the green-blue open system are considered precursors ideas for the proposal of green infrastructure—GI as a way to rethink the landscape planning and design of the city today, having the marginal landscape as a base.

1.2 GI Strategies and the “Sapphire and Emerald Necklaces at City of Vitoria-Gasteiz”

Capital of the Basque Autonomous Community, Vitoria-Gasteiz, Spain, is the area’s largest and most compact city. It covers 276.08 km2and has a population of 253,093 habitants[13].The methodological strategies for defining the urban green infrastructure network of Vitoria-Gasteiz emerged in 2013. In this context, GI is a “strategically planned network of natural, rural and urban green spaces (including rivers and other forms of water). These are managed in order to offer a broad range of socio-ecosystem services that provide environmental, social and economic benefits and for the health of the inhabitants of the city”[5].

These strategies were developed to promote the renaturing of the city in dialogue with the conservation biodiversity and climate change plans in order to strengthen the recognition of Vitoria-Gasteiz as the European Green Capital of 2012 (Fig. 1). The Vitoria-Gastiez sapphire and emerald necklaces transformed a third of its areas into public spaces and created 45 m2of green areas per inhabitant[14].

In Spain, each autonomous municipality has three years to develop their own GI strategies based on the European Commission’s guidelines onGreen Infrastructure(GI)—Enhancing Europe’s Natural Capital(2013). The Spanish legislation 33/2015, which refers to natural heritage and biodiversity, incorporates European legislation on GI, implementing the national strategy for green infrastructure and ecological connectivity and restoration. However, as the European Commission’s guidelines focus on presenting the concept, the principles and the elements of GI,instead of proposing also a multi-scale and multifunctional methodological place-based approach.

For Tojo[15], a common aspect of the GI strategies in Spain is the proposal of infrastructure as an articulating element between ecological networks and city systems. This is the case of Vitoria-Gastiez and its green infrastructure system, which “has been defined based on the premise that the natural and semi natural spaces included in urban green areas provide greater benefits when these are integrated in a system and are managed systematically”[13].

1.3 Vitoria-Gasteiz GI Methodological Strategies:Reconsidering the Marginal Landscape

Methodological strategies adopted by Vitoria-Gastiez green infrastructure plan and design bring answers to rethinking Olmsted’s theory. A layered reading of the territory was developed to understand landscape as infrastructure, structured in a GI regional network. First, it tried to understand the insertion of the city in the álava Central Bioregion and its ecological aspects, starting at the margins of the territory. Vitoria-Gasteiz, stands out as one of the great biodiversity reserves of the great ecological corridor of the Cantabrian Mountains-Pyrenees-Massif Central-West Alps. It also plays a leading role in relation to the Iberian Peninsula’s northern region and the Pan-European Ecological Network.

Cartographies were superimposed, aiming to identify the characteristics of the green-blue spaces of the region, seeking to integrate the margins in this landscape design. In territory scale, this took into account the network of protected spaces of environmental interest, natural parks, protected biotopes, arboreal types of heritage importance,European Network of Protected Natural Areas(Natura 2000), the network of conservation zones of wetlands of theRamsar Convention,the network of singular landscape units present in the catalog of the bioregion, the Alava Plains, and the areas of territorial environmental protection.In local scale, the elements of the sapphire and emerald green-blue spaces were identified: parks,gardens, cemeteries, green spaces, forests, thickets,meadows, crops, vegetable plots, wetlands, rivers,streams and further derivations (Fig. 2).

As a result of this analysis, the role of this compact city from its landscape on the margin of the plain was identified. In the marginal landscape,the green and agricultural belt was implemented in 1995 to contain the urban sprawl and of recovering ecologically degraded areas through the creation of GI, where the margins make a fundamental contribution (Fig. 3).

The next step was to establish a layered reading, which demonstrated the relationship between urban infrastructures related to the water network (aquifer, rivers, streams, dykes,wetlands and sanitation network), the parks of environmental interest in the green belt, and the urban green plot. In addition, fragmented areas characterized by vacant, obsolete and/or brownfields were also identified in the green and urban plot, mainly on the margins. After that, these readings were overlaid and other information was added: agricultural belt, public tours (paths and boardwalks, among others) and sustainable mobility infrastructure. The connectivity of the margins in the system is promoted by making physical and ecological movements easier, with urban walkscapes and ecological itinerary and green belt walking tour(Fig. 4).

2 The Strategy of the Emerald and Sapphire Necklace in the Vitoria-Gasteiz Margins

The relationship between the existing infrastructure network and the territory’s physical,ecological and cultural connections was identified,with the definition of a blue-green system network that brings together core elements, node elements and connectors. The ecological perspective was deepened by incorporating the principles of the Theory of Landscape Ecology[16-19]. In the context,the following terms were used: 1) Core elements,spaces with a high level of naturalness and an adequate state of conservation in areas adjacent to the city; 2) nodes, green spaces located within the city, which, due to their size and/or location,represent basic structural parts of the urban green system; 3) connectors, elements of a linear nature,the main function of which is to facilitate the connection between core elements and nodes[14].

The green and agricultural belt in Vitoria-Gasteiz has core elements that are understood as areas of environmental interest of “a total surface area of 1 016 hm2(of which 889 hm2correspond to periurban parks and 127 hm2to agricultural areas”[14]. Parks, squares, gardens and meadows are among the features considered nodes, occupying the peripheral and downtown area, characterizing the riverside landscape in margins.

Most nodes are defined and delimited spaces,organized into main or secondary, depending on their importance. Diffuse places are elements present in buildings that can receive some type of use, such as green walls and green roofs.Connectors are linear elements that articulate nodes and core elements, which incorporate traditional green corridors and waterways linking parts of the marginal region itself and this with the central area of the territory. The principle connection strategies are organized in the east-west connector, waterways north-south connectors and no-waterways northsouth connectors (Fig. 5).

The result of Olmsted’s theory rethought today produces a methodology for understanding integrated ecological processes and other infrastructures systematically. Landscape is seen as infrastructure, exploring its multiple dimensions(different infrastructures, temporalities, connectivity and functionality) to plan and design climateadapted and biodiverse cities. In this context, the renaturing strategies defined a “green and blue necklace” that differed from traditional planning and design in that it embraced the margins.Therefore, the margins gain protagonism and reinforce the value of the green and agriculture belt in the contemporary context.

2.1 The Emerald and Sapphire Necklace: The Role of the Parks in the Margins

In the case of Vitoria-Gastiez, there are parks in its marginal areas: Zabalgana (Fig. 6),Zadorra (Fig. 7), Olarizu (Fig. 8), Humedales de Salburua(Fig. 9) and Armentia(Fig. 10). They play the role of core elements in the ecological network, embracing the water network. They dialogue either with the green and agricultural belt, or with the system of open spaces that gives access to the heritage sites in the city. They also reveal the countryside landscape and rethink the communities’ relationship with the edges of the city and its riverside landscapes.

As in the Olmsted’s strategies, water, the“sapphire necklace”, assumed a leading and resilient role in the design of this marginal landscape, as it helped structure these parks system technically and aesthetically. It promoted the physical and ecological connections in territory.

2.2 Rethinking Marginal Territories: The Democratic Dimension

At Vitoria-Gastiez, the democratic dimension of the green-blue space system proposed by Olmsted is created not only in these parks but also in the walkable and cyclable green routes that give the city user more opportunity to discover all these spaces and their programs (Botanical Garden-Olarizu, Nature Interpretation Centre-Ataria, among others). One of the main objectives is to “promote public use compatible with green spaces, increase opportunities for leisure and recreation, increase accessibility and country-city connections, preserve the cultural heritage and traditional landscapes and increase a sense of identity and belonging”[14].

Innovating the Olmsted’s theory, the involvement of the community was reinforced from the beginning to the end of the project,through workshops, talks and exhibitions. Practices to raise awareness of the marginal landscape’s green infrastructure network and the role of its blue-green space were carried out, with planting campaigns in project areas, programs such as“Adopt a tree” or the construction of family gardens and urban and school gardens. Other ways of raising awareness are the elaboration of a biodiversity inventory, as well as guided or free tours by bicycle or on foot that invite the community to see the margins.

3 Emeralds and Sapphires from Its Margins: The Local Case of the Zadorra Park Project

Reconsidering the Olmsted’s theory and incorporating the Theory of Landscape Ecology,green infrastructure is defined based on the benefit of the green and blue system as whole, but each element has its own importance. Zadorra is the main river in the Municipality of Vitoria-Gasteiz,and regionally it is part of the European Network of Protected Natural Areas (Natura 2000), due to its high concentration of biodiversity. Located in the northern region of the territory, its 13 km-long of the linear park along the river limits the expansion of the city to the north, composing its green belt. So far, only two sections have been executed.

3.1 Connecting Urban with Rural Marginal Landscapes in Different Scales: Agricultural Areas and Waterside

Greenways, bike paths and trails connect the park with the surroundings, mainly with the agricultural areas in the region. The project seeks to the transition from urban to rural landscapes,highlighting the role of the green open space system, from the green belt, especially the agrarian areas of high ecological value and historical and artistic significance.

The foodscape and the sounds of the water gain prominence in an organic design, steeped in naturalistic principles, with the use of resilient native species. Minimal elements invite the user to see how the vegetation is structured and these markers require little maintenance. The choice of plant typology is also conditioned by the amount of water present. The area suffers from heavy flooding, so a sustainable drainage system was proposed to optimize drainage performance,recovering Olmsted’s practices.

3.2 The Wildness of the Margins: Obsolete Areas and Less Valued Plants

Olmsted artificially created a wild aesthetic in the landscape, sustaining that wildness could be incorporated in the urban skyline to bring the community closer to nature, inviting users to perceive the landscape democratically[3-4]. At Vitoria-Gastiez the system of blue-green spaces also appears as a way of rethinking the marginalized,degraded and unoccupied areas of the territory,through contemporary ecological restoration, with the use of native species, creating different habitats and improving resilience and biodiversity, as well as the gradual transition in the interactions between humans and nature-culture (Fig. 11).

This concept has been applied to the design of the city’s ecological and sociocultural network,with a more organic vegetation physiognomy that is more engaged in the dynamics of the place, easier to manage and recognized by the community. This presents an experience with nature that gray and overbuilt cities are losing, and which Olmsted, in a different time and under different conditions, also fought to recover and value.

Everything on the margins is involved:agricultural areas, the waterside, obsolete areas and less valued plants. The marginal landscape is the protagonist, and it connects physically, ecologically and aesthetically with the place. Beyond this multiscale methodological of GI proposal for planning and design from the green belt to the park that rethink Olmsted theory nowadays, the different communities are invited to be part of and fight for their landscape[20].

4 Conclusion

Reconsidering Olmsted’s theory of the Emerald Necklace is fundamental to rethinking the landscape as the infrastructure of urban sustainable development, especially as we address the impacts of climate change and lack of biodiversity. Within this context, the system of green-blue open spaces are defined in green infrastructure strategies and projects, articulating the different dimensions of landscape on multiple scales.

When establishing methodological strategies that start from the first readings of the project,this multiscale dimension is observed. There is an effort to understand the territory on many scales(ecological, aesthetic, social and cultural values),defined in maps and syntheses, which are then translated into the form of a project.

The holistic design of the infrastructure of the landscape of Vitoria-Gasteiz is generally guided by the premises of the Theory of Landscape Ecology, paying special attention to the promotion of biodiversity, through physical and ecological connectivity, seeking to contribute to the reduction of the fragmentation of green areas in the territory.In this way, it develops the understanding of the ecological network composed of cores, nodes and connectors elements. Here, the elements of the green and blue space system were identified and organized in cores, nodes and connectors, following their ecological contribution in the network, valuing appreciation of its “emeralds”, or green areas, and its “sapphires”, the bodies of water.

At the local scale, the idea was to use ecological restoration, to bring nature and humans closer, with native species and Nature-based Solutions. This brings a contemporary perspective to Olmsted’s idea of joining the wild to the city.Creating an artificial structure based on Naturebased Solutions along with today’s technology, it is possible to invite the community to perceive and transform their marginal landscape, guided by water. Special attention is given, as it was by Olmsted, to providing technical but also artistic solutions for the marginal riverside landscape. As in the Emerald Necklace in Boston, in Vitoria-Gastiez the green-blue space system pays special attention to the contribution of the margin to the sapphire and emerald of the territory, valorizing the already existing green and agriculture belt.

Thinking about the landscape of cities from the standpoint of their marginal landscape also allows for greater contemporary articulation between urban and rural areas, revising the reduction of productive landscapes in the territory and the understanding of rural areas as places of food production and no longer in contact with nature. The productive landscape is understood and incorporated more effectively and at different scales, for example giving parks great views to agricultural areas, and incorporating rural trails,urban gardens and family gardens.

This is an important contribution to rethinking the traditional planning and design practices nowadays, making the marginal landscape a driver of strategies and their translation in terms of urban planning and design. The marginal landscape here is fundamental in the structuring of the green,agricultural belt, the blue network, and the other green axes that physically and ecologically connect the system of green and blue spaces. The ecological and sociocultural dimensions are jointly incorporated in their decision-making about the future of the region, and a lot of work is done to raise the awareness of the communities about their landscape,for example, with walkscapes and a campaign to adopt trees. The community is not only invited to perceive but also to be part of the landscape, to guarantee its right to it, recovering the democratic values of the park propounded by Olmsted.

It should be remembered that 29% of the urban population currently live in slums[21], and the majority live on the outskirts of cities, mostly under very different conditions from Vitoria-Gastiez, lacking urban infrastructure and guarantee of equitable rights. In parallel, the outskirts are generally areas of environmental interest that theParis Agreementand theConvention on Biological Diversityare trying to protect. Therefore, this experience can provide inspiration to other countries in rethinking their margins with a place-based methodology, updating and rethinking Olmsted’s theory today.

Sources of Figures:

Fig. 1, 6～11?Camila Gomes Sant’Anna; Fig. 2～5?Caroline Fernandes, adapted from https://www.vitoriagasteiz.org/j34-01w/catalogo/portada?idioma=es.

(Editor / LI Qingqing)