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CAS Workshop on Ecosystem Succession Theory and Practice of Ecological Restoration 恢复生态学的几个焦点问题 彭少麟
陆宏芳 （中国科学院华南植物研究所，广州 510650） 摘要：本文就恢复生态学概念、近期的发展趋势、传统生态学理论在生态恢复过程中的应用及恢复生态学的社会性等恢复生态学核心问题展开论述。 1． 恢复生态学的定义 恢复生态学是一门年轻的学科，迄今尚无统一的定义。代表性的有三方面的学术观点：强调受损的生态系统要恢复到理想的状态；强调其应用生态学过程；强调生态整合性恢复。我们认为恢复生态学是研究生态系统退化的原因与过程，及其恢复的机理与技术的一门综合性学科。 2． 恢复生态学近期的主要发展趋势 （1）当前的恢复生态学强调自然恢复与社会、人文的耦合。认为恢复生态是全球性的，不只是自然的过程，应有全社会的支持，包括政治、经济和人文的介入。恢复生态在实施前应进行目标设计，过去的模式不一定是未来所需要的；应该在充分考虑未来生态系统发展的基础上，对恢复量化，再付之实践。恢复生态的价值不仅是局部生态系统结构和功能的恢复，更有全球意义，应进行联网研究，在不同的景观上研究。生态恢复的有效实施，依赖于政治上的支持、立法的和相关的机构的保证。21世纪是城市的世纪，城市的未来亦是人类的未来。城市的生态恢复不止为自然景观问题，还包括人文景观、历史景观、文化与美感等，特别强调社区艺术。必须开展生态恢复教育，为人类与自然的和谐发展提供机会。 （2）恢复生态学研究无论是在地域上还是在理论上都要跨越边界。就研究地域而言，生态系统的结构和功能是只有自然边界而没有政治边界的，自然地理区域的统一性决定了生态系统恢复行动跨越政治边界的必要性，有效的区域或流域的生态恢复往往需要多个行政区以至多个国家的共同参与。在理论支撑方面，恢复生态学的许多理论、方法来源于生物学、地学、经济学、社会学、数学等自然学科，以及工程学、林学、农学、环境学等应用性科学。生态恢复的过程和机理研究，必须从不同的空间组织层次上来进行。生态恢复的研究需要跨越学科边界的学术交叉。 （3）恢复生态学研究以生态系统为基点，在景观尺度表达。随着环境问题与社会经济发展的全球化，生态系统乃至景观等大尺度的研究日益成为恢复生态学新的研究热点。生态系统是开展生态学以及其它分支学科研究工作的最基本和完整的单元，只有认识生态系统的结构和功能，才能了解生态系统在各种环境，尤其是在当今全球关心的气候变化条件下的发展趋势。而生态恢复的实践也是以具体的生态系统作为研究的对象。生态系统的研究理论和概念，是支撑生态系统经营和管理的理论核心，也是生态恢复实践的理论基础，对生态系统的完整了解才是生态实践的重要条件。2004年第15届国际恢复生态学大会的会议主题已定为：恢复、景观与设计。 3． 传统生态学理论在生态恢复过程中的应用 退化生态系统的恢复与重建是一项十分复杂的系统工程，尤其需要生态学理论的指导。主导生态因子原理、元素的生理生态原理、种群密度制约原理、种群空间分布格局原理、边缘效应原理、生态位，及演替理论等均在恢复生态学中有重要应用。本文结合案例，着重论述了演替理论在生态恢复的应用。 生态系统的动态发展，在于其结构的演替变化，如物种的组成、各种速率过程、复杂程度和随时间推移而变化的组分的变化。最高效率地重建植被或生态系统的可能性，是直接地依赖于对动态原则理解的程度而转移，必须顺应随时间过程的演替规律，成功的人工植被或生态系统都是在深入认识生态原则和动态原则基础上，模拟自然植被或生态系统的产物。因此，退化生态系统的恢复与重要，最有效的和最省力的是顺从生态系统的演替发展规律来进行，生态系统演替理论是指导退化生态系统重建的重要的基础理论。 森林演替是一个动态过程，是一些树木取代另一些树木，一个森林群落取代另一个森林群落的过程。在自然条件下，森林的演替总是遵循着客观规律，从先锋群落经过一系列演替阶段而达到中生性顶极群落，通过不同的途径向着气候顶极和最优化森林生态系统演变。南亚热带区域，在排除人为干扰的情况下，森林演替的进程以马尾松或其它先锋种群的入侵和定居为起点，它们在荒地上有高的生活力并生长很快，但成林后结构简单，盖幕作用小，透光率大，高温低湿，日夜温差较大。但其生长为阔叶阳生性树种，如椎栗、荷木等提供较好的环境，这些阳生性树种入侵先锋林地并生长良好，林内盖幕作用和阴蔽增加。结果，先锋种群不能自然更新而消亡，但中生性树种，诸如厚壳桂和黄果厚壳桂等却有了合适的生境而发展起来，群落更为复杂，阳生性树种也渐渐消亡，群落趋于中生性树种为优势的接近气候顶极的顶极群落。中国热带亚热带地区植被恢复与重建30余年的研究表明，该地区森林演替的进展是较迅速的。其演替依次经过先锋针叶林阶段、以针叶树种为主的针阔叶混交林、以阳性阔叶树种为主的针阔叶混交林、以阳生植物为主的常绿阔叶林和以中生植物为主的常绿阔叶林，最终演替为中生性顶极群落。该区域退化生态系统的植被重建，完全可以依据其常规发展的一般，人为的进行种类构建，加速退化生态系统的植被恢复。 4． 全球变化生态学与恢复生态学的交叉 已有实验证明，在生态恢复进程中，生态系统各阶段的优势种对演替起主导性作用。这些优势种在全球变化压力下的响应明显，进而影响了整个生态恢复演替的进程。在生态恢复进程对全球变化的反馈方面亦有不少研究。在广东的恢复生态学研究表明，其森林覆被率已由1978年的26％增加至1998年的51％。其新增林地每年吸收广东省排放CO2总量的一半。 5．恢复生态学的社会性 人类社会与自然环境的协调可持续发展，不仅要求实现生态环境的可持续，同时亦要求实现人类社会与经济的发展。这就要示生态系统的恢复与重建必须同时实现生态、经济与社会效率的三重优化。 华南植物研究所生态中心在中国热带、南亚热带进行的退化生态系统的恢复与重建研究历时30余年，所产生的显著经济和社会效益，在各个实验站点均已有所反映。中国科学院小良热带人工林生态系统定位研究站，几十年来在不能适应致力退化生态系统的恢复、整治和重建的过程中，定位站的生产收入逐年增加，从1960年的1884元上升到1987年的2193967元，1989年的固定资产总值为1880000元，大大超过历年国家投资总额。此外，通过小良站为示范样板，从而使小良站周围369km2的水土流失得到根治，改善了农业生产条件，使水稻年亩产由过去一、二百斤，提高到一千二百多斤。鹤山开放实验站利用其集水区上、中、下不同的自然环境条件而构建的“林－果－草－鱼”复合农林模式，及其优化人式林模式均得到当地政府和农民的高度评价，得以大面积推广。构建的混交林，连片推广29万，成为广东最大的连片混交林，对防治病虫害、改善区域环境起到重要的作用，成为广东绿化达标后林地管理和林分改造的示范样板。广东省五华试验区在对退化生态系统的综合整治的同时，1986-1990年试验区的农业总产值每年均在增长。若以1985年为100，1986年则为107；1987年为141.4；1988年209.72；1989年为308.74；1990年为350.53。五年时间产值增加了2.51倍。平均年递增率为28.5%，三年时间就可翻一番。同时，当地农田土壤肥力亦得到显著提高。
关键词：恢复生态学；概念；发展趋势；演替理论；社会效益；可持续发展 Some
Key Ponits of Restoration Ecology
Peng
Shaolin Lu
Hongfang (South
China Institute of Botany, Chinese Academy of Sciences, Guangzhou
510650, China) Abstract:
Five key points of restoration ecology was discussed in this paper,
which are the concept of restoration ecology, the current trends of
restoration ecology, the application of traditional ecology theory
in the practice of ecological restoration and the social
characteristic of restoration ecology. 1.
The conception of restoration ecology Restoration ecology still has no
general conception, as a young subject. There are mainly three
schools about it. The fist school emphasizes that the degraded
ecosystem should be restored into ideal station. The second school
highlights the process of application ecology. The third school
insists the integrative restoration. We think that restoration
ecology is a integrative subject to study the reason and process of
the degradation, and the mechanism and technology of restoration. 2. Some
main trends of restoration ecology study (1) Current restoration ecology study
highlights the integration between natural restoration and social
culture. Ecological restoration is a global study and practice. It
needs the support of not only national science study but also
social, economic and cultural development. Target design should be
made before the practice of restoration to make the result of
restoration meet the need of future society. The valuation of
ecological restoration not only shows on ecosystem scale but also
shows on global scale. Integrative studies of different landscape
styles are needed. The 21st century is a urban century. The future
of urban is also the future of human being. The ecological
restoration of urban system especially highlights the community art.
It is not only a problem of natural landscape, but also a problem of
cultural, history, art landscape etc. (2) Restoration ecology study
emphasizes the integration both in section and in theory. There are
no political boundaries for the structure and function for ecosystem
but natural boundaries. The efficient restoration needs the
cooperation of several regions, even nations. To theory structure,
most of the restoration ecology theory comes from some natural
sciences, such as biology, geography, economics, sociology and
mathematics, and some application sciences, such as engineering,
forestry, agriculture and environmental sciences. The study of the
restoration process and its mechanism needs the integration of
different section scales. The ecological restoration study needs the
integration of different sciences and subjects. (3) Based on ecosystem study, the
process and result of ecological restoration shows on landscape
scale. More and more emphasize of ecological restoration study was
put on ecosystem and landscape scales, with the globalization of
environmental and economic problems. Ecosystem is the basic unit for
the study of ecological and its branch subjects. The development
trend of ecosystem under different environment, especially the
pressure of global change, cannot be known until the structure and
the function of ecosystem are understood. Ecological restoration
study is always practiced in some ecosystems. Ecosystem theory is
the most important ecological theory to support ecosystem management
and ecosystem restoration. The topical of 15th
international restoration ecology conference has been confirmed as
“Restoration, Landscape & Design”. 3. The
application of traditional ecological theory in restoration process The restoration and rebuilt of a
ecosystem is a complex system engineer, especially need the
direction of ecological theory. Most of ecological theories, such as
key elements principle, the physiologic ecological of elements,
density restriction of population, space pattern of population, edge
effect, niche and succession theory, have been widely used in the
study and practice of restoration. With case studies, the
application of succession theory in ecological restoration was
highlighted. The dynamic of ecosystem shows as the
succession of its structure, such as the change of its species,
process speed, complexity and components. The efficient of
vegetation restoration depends on the understanding of ecological
dynamic theory, especially the succession theory. All of the
successful restoration ecosystems came from the simulation of
natural vegetation or ecosystem. Only following the succession
theory，can the restoration obtain twice the
result with half the effort. Forest succession is a dynamic process,
during which some tree plants replace others, a forest community
replaces the other. Forest succession always abides by objective law
under natural conditions starting at a stage of pioneering community
and finally reaching a mesophytic climax community via a series of
succession periods, or developing towards climatic climax and
optimized forest ecosystem through different ways. The forest
succession in the low subtropical region normally occurs with the
invasion and location of some pioneer species such as Pinus
massoniana. These pioneer species have high viability and can
grow fast on deserted lands. However their matured forests are
characterized by a simple structure, small canopy coverage, high
light penetration, higher temperature, lower humidity, and large
diurnal temperature difference. Their growth can, on the other hand,
provides sunny broadleaf tree species such as Castanopsis
chinensis, Schima superba, with a still better environment. The
invasion of these sunny species into the pioneering community and
their successful growth increase the covering effect and shade.
Consequently, pioneering populations are unable to regenerate,
therefore decline. The mesophytic tree species, such as Cryptocarya
chinensis and C. concinna, obtain a suitable habitat to
develop making the community more complex. As the sunny tree species
gradually decline, the community tends to incline towards climatic
climax that is dominated by mesphytic tree species. Reconstruction
of forest vegetation should follow this regularity in subtropical
region. 4. The
integration of global change ecology and restoration ecology Some studies showed that the succession
process mainly effected by the dominant species
of every succession periods. Global change has great effects
on those dominant species, thus has great effects on restoration
process. There are also lots of studies on the feedback effects of
vegetation on global change. The restoration study in Guangdong
province shows that the forest coverage had raised from 26% in 1978
to 51% in 1998. The new developed forest absorb half CO2
discharged from Guangdong province. 5. The
sociality of restoration ecology The harmonious sustainable development
of human society and natural environment requires the realization of
both sustainable ecological environment and the development of
social economy. Thus, restoration study must focuses on the
realization of ecological, economic and social effects
simultaneously. Significant economic and social effects
brought about through restoration and reconstruction of degraded
ecosystems was reported in all of the experimental stations funded
by South China Institute of Botany in low subtropical China.
Xiaoliang station had been engaged in renovation and reconstructing
degraded ecosystem for decades. Its production income was raised
from 18 440 yuan (Chinese currency) in 1960 to 2 193 967 yuan in
1987. It was estimated that fixed assets of Xiaoliang station was 1
880 000 yuan in 1990 which was much more than total accumulative
investment by state. Moreover, loss of water and soil in surrounding
areas of 369km2 were brought under permanent control
through extending demonstration models provided by Xiaoliang
station. It had amelionrated conditions of agricultural production.
The local productivity of rice has increased from 100kg/acre to
600kg/acre. Optimized man-made forests, “forest-fruit
tree-grass-fish” and “forest –fruit tree-grass-nursery”
ecological models on hilly lands set up in Heshan station were
extended to surrounding regions on a large scale. It constituted one
of the largest mixed forests in Guangdong province and played
important role n the prevention and control of plant diseases and
elimination of pests, and in amelioration the regional environment.
The mixed forest model served as a demonstration for management and
remoulding after afforestation in the province simultaneously.
During the renovation period (1986-1990) total value of agricultural
production in the experiment area had increased annually, following
the restoration study of Huhua station. Assuming that it was 100 in
1985, then it would be 107 in 1986, 141.40 in 1987, 209.72 in 1988,
308.74 in 1989 and 350.53 in 1990. Production value was increased
2.51 times in five years. Yearly average increment was 28.55. It
doubled once three years. The soil fertility was increased
simultaneously. Key words: restoration ecology;
conception; development trend; succession theory; social benefits;
sustainable development
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