دانلود ترجمه مقاله تجدید و نوسازی اکوسیستم تخریب شده در اراضی خشک و نیمه خشک – انتشارات وایلی

فهرست مطالب:

چکیده
لغت شناسی پایه
خصوصیات حیاتی اکوسیستم
بحث
۱۰ فرضیه برای احیا و اصلاح اکولوژی
نتیجه گیری

بخشی از ترجمه:

مدل عمومی ارایه شده به توصیف تخریب اکوسیستم برای کمک در خصوص تصمیم گیری هنگام احیا، باز سازی و تخصیص مجدد می تواند یک پاسخ و واکنش ارجح باشد. دو مسیر اخیر اغلب زمانی پیشنهاد می شوند که یک یا چند آستانه برگشت ناپذیری در روند تخریب اکوسیستم از مقدار نرمال عبور کنند و یا هنگامی که احیای غیر فعال یک شرایط تخریب شده و یا تنزل یافته غیر ممکن باشد. یک زمینه علمی جوان ولی در حال شکوفایی احیای اکولوژیکی و زمینه قدیمی تر باز سازی و مدیریت دامنه پایدار اراضی خشک و نیمه خشک دارای نقاط مشترک بسیار زیادی به خصوص در مقایسه با تخصیص مجدد اراضی می باشد که بدون ارجاع به برخی اکوسیستم های موجود قبلی انجام شدند. بعد از تشریح برخی از اصطلاحات پایه، ما ۱۸ صفت اکوسیستم اساسی را برای ارزیابی مراحل آزمایشات تخریب و برنامه ریزی در احیا و باز سازی اکوسیستم های تخریب شده استفاده کردیم. در نهایت، ما ۱۰ فرض را در خصوص احیا و باز سازی بوم شناسی ارایه کردیم که قابل تعمیم به ASAL و شاید همه اکوسیستم های خشکی می باشد.

در کشور های شمالی، جایی که اکولوژی احیا اغلب دنبال می شود، ارزش های زیبایی شناسی و ذاتی( نایس ۱۹۸۶) موجب انجام کار ها و مطالعات فراوانی در این زمینه ها شده اند. هدف اصلی ایجاد یک موزه زنده و یا برگرداندن همه چیز به حالت قبلی می باشد. از سوی دیگر، طیف وسیعی ازمنابع بوم شناسی در خصوص کشاورزی، جنگل داری و مدیریت مرتع در جنوب به خصوص در اراضی خشک و نیمه خشک حاکی از آن هستند که افراد خود نیروی غالب هم در اکوسیستم های طبیعی و هم اکوسیستم های زراعی می باشند. مسائل ااصلی به قرار ذیل می باشند. نخست، آیا تولید اولیه و ثانویه را می توان با فنون مدیریتی جدید افزایش داد و یا پایدار کرد و دوم این که این فنون چه اثراتی می توانند روی تنوع زیستی و پایداری اکوسیستم داشته باشند. مدل ها و ایده های در خصوص راهنمایی این زمینه ها و رشته های کاربردی اغلب بر گرفته از منابعی به غیر از اکولوژی احیا و بیولوژی حفاظت هستند. با این وجود ما اعتقاد داریم که مرتعداران، مهندسان زراعت، بیولوژیست های حفاظتی و بوم شناسان احیا می توانند از تبادل بیشتر داده ها و روش ها هم در شمال غنی و در جنوب فقیر بهره مند شوند.( دیکستریوز ۱۹۴۹، براد شاو ۱۹۸۳، جردن و همکاران ۱۹۸۷).

بخشی از مقاله انگلیسی:

Abstract A general model is presented describing ecosystem degradation to help decide when restoration, rehabilitation, or reallocation should be the preferred response. The latter two pathways are suggested when one or more “thresholds of irreversibility” have been crossed in the course of ecosystem degradation, and when “passive” restoration to a presumed predisturbante condition is deemed impossible. The young but burgeoning field of ecological restoration, and the older field of rehabilitation and sustainable range management of arid and semiarid lands (ASAL), are found to have much in common, especially compared with the reallocation of lands, which is often carried out without reference to pre-existing ecosystems. After clarifying some basic terminology, we present 18 vital ecosystem attributes for evaluating stages of degradation and planning experiments in the restoration or rehabilitation of degraded ecosystems. Finally, we offer 10 hypotheses concerning ecological restoration and rehabilitation as they apply to ASAL and perhaps to all terrestrial ecosystems. ICentre d’Ecologie Fonctionnelle et Evolutive L. Emberger, C.N.R.S., B.P. 5051 34033 Montpellier Cedex 01, France 2Estaci6n Experimental Quilamapu, I.N.I.A., Casilla 426, ChillAn, Chile 30RSTOM, B.P. 434, 1004 El Menzah 1, Tunisia 0 1993 Society for Ecological Restoration I n the nations of the “North,” where restoration ecology has mostly been pursued thus far, aesthetic or intrinsic values (Naess 1986) have motivated most efforts to date. The primary goal has been to create “living museums,” or to put things back as they once were. On the other hand, the vast literature of ecology applied to agriculture, forestry, and range management in the “South,” particularly in arid and semiarid lands (ASAL), takes for granted that people will continue to be the dominant force in both natural and agro-ecosystems. The main issues are, first, whether primary and secondary productivity can be increased or sustained by new management techniques and, second, what effects these techniques might have on biodiversity and ecosystem stability. The models and ideas guiding these applied fields have mostly come from sources other than restoration ecology and conservation biology. Nevertheless, we believe that range managers, agronomic engineers, conservation biologists, and restoration/rehabilitation ecologists could all benefit from greater exchange of ideas and methodology, both in the rich North and the poorer South (see Dyksterhuis 1949; Bradshaw 1983; Jordan et al. 1987). At a higher level, it is the fragmentation and degradation of entire landscapes that both restorationists and rehabilitators must combat. When economic and cultural practices are modified in the direction of ecological sustainability and conservation of biodiversity, and when restoration or rehabilitation is applied to all partially degraded ecosystems, with the help of all the necessary and appropriate scientific disciplines, the result would be-to borrow a phrase from Hobbs and Saunders (1991)-an attempt at “reintegration of fragmented landscapes” (Fig. 1). After clarifying some basic terminology, we will discuss 18 vital ecosystem attributes for evaluating degradation and planning experiments in the restoration or rehabilitation of degraded ecosystems. Finally, we offer 10 hypotheses concerning ecological restoration and rehabilitation. Basic Terminology Restoration Sensu Strict0 and Sensu Late. Restoration of degraded ecosystems can be likened to the restoration of a Renaissance painting that has deteriorated over time but still reveals its initial lines and colors sufficiently for the fine arts restorator to do his or her work. Analogously, ecological restorationists seek a complete or near-complete return of a site to a pre-existing state. The Society for Ecological Restoration (SER) defines restoration as “the intentional alteration of a site to establish a defined indigenous, historic ecosystem. The goal of this process is to emulate the structure, functioning, diversity, and dynamics of the specified 8 Restoration Ecology MARCH 1993 Restoration and Rehabilitation. I. Figure 1. Relationships and potential pathways for exchange among ecological restoration and rehabilitation of degraded ecosystems and various branches of ecology, conservation biology, and sustainable land and bioresource management, including soil science. ecosystem.” Implicit in this definition is the notion that restoration seeks to reassemble, insofar as possible, some predefined species inventory. wever, since it is rarely possible to determine exwhat historic or prehistoric ecosystems looked or how they functioned, let alone establish the full species list of indigenous communities, restoration efforts may be plagued by ambiguities in both their goals nd criteria of success (Cairns 1989, 1991; Simberloff 990). We suggest using the term “restoration sense stricto” to describe endeavors corresponding to the SER definition, as opposed to restoration sense Z&o, which seeks simply to halt degradation and to redirect a disturbed ecosystem in a trajectory resembling that presumed to have prevailed prior to the onset of disturbance. :’ Despite this difference, the primary goal of both sense stricto and senstl late restoration is the conservation of indigenous biodiversity and ecosystem structure and dynamics. They thus differ from a third possi- \! ble response to ecosystem degradation, which we call rehabilitation. Rehabilitation. Rehabilitation, in our sense, seeks to repair damaged or blocked ecosystem functions, with the primary goal of raising ecosystem productivity for the benefit of local people. Moreover, it attempts to achieve such changes as rapidly as possible. However, a rehabilitation project resembles a restoration attempt in adopting the indigenous ecosystem’s structure and functioning as the principal models to be followed, insofar as they can be determined or guessed. That is, they both aim at recreating autonomous or self-sustaining ecosystems, which are characterized by biotic change or succession in plant and animal communities, and the ability to repair themselves following natural or moderate human perturbations. Thus, restoration and rehabilitation projects must also share as explicit or implicit working goals the return to former paths of energy flow and nutrient cycling, and the reparation of conditions necessary for effective water infiltration and cycling throughout the ecosystem’s rhizosphere (Allen 1988, 1989; DePuit & Redente 1988). However, whereas restoration sensu stvicto invariably seeks a direct and full return to the indigenous, historic ecosystem, restoration sense late and, particularly, rehabilitation may settle on one of many possible alternative steady states, or a synthetic “simplified ecosystem” as an intermediate step in their long-term goals (Fig. 2). The alternative steady states might or might not have occurred in the process of degradation of the original, predisturbance ecosystem. In any case, they are-like our so-called “simplified ecosystems”-a practical method for designing, managing, and evaluating ecosystem-level experiments (Fig. 2). What we call rehabilitation has often been called reclamation, particularly in conjunction with mine-tailing revegetation (Bengson 1977; Bradshaw 1987). But reclamation has also been used synonymously with both restoration and with some examples of what we call reallocation. Reallocation. A general term is needed to describe what happens when part of a landscape, in any state, is assigned a new use that does not necessarily bear an intrinsic relationship with the predisturbance ecosys tern’s structure or functioning. We call this reallocation. For simplicity’s sake, reallocation pathways in Figure 2 are indicated only after various stages of ecosystem degradation have taken place and one or more thresholds of irreversibility have been crossed. In reality, it can occur in the case of a slightly disturbed ecosystem or even an undisturbed (predisturbed) one. Problems arise when reallocated sites sprawl over landscapes in a more or less anarchic fashion. In contrast with restoration and rehabilitation, reallocation assumes a permanent managerial role for people and normally requires ongoing subsidies in the form of energy, water, and fertilizers. The huge plantations of the fodder shrubs in North Africa, such as Atviplex, Acacia, and Opuntiu spp., are examples of reallocation. By contrast,. the native perennial grasses we have introduced or reintroduced there (Cha’ieb 1990; Chai’eb et al. 1992a, 1992b) survive direct grazing, reproduce sexually, and eventually become naturalized. They form part of a rehabilitation experiment. cosystem of Reference. As Cairns (1991), Simberloff (1990), and Sprugel(l991) point out, it’s often not clear what ecological yardstick is being used when a restoration or rehabilitation experiment is being set up. Yet for purposes of project design and evaluation, it is desirable to establish ahead of time some standard of comparison and evaluation, even if it is arbitrary. We call this the ecosystem of reference. In restoration, this will normally correspond to the SER’s “indigenous, historic ecosystem,” but in some rehabilitation (and, of course, reallocation) projects, it may be something entirely different, depending on the state of advancement of the ecosystem’s degradation and on the needs of landowners or local people. /Alternate Steady-States. It is often assumed that if ecosystem degradation has not progressed too far, a return to an “indigenous, historic” state is possible simply by removing anthropic stresses (intentional fires, wood clearing, overgrazing, etc.) and allowing natural processes to do the rest. Yet in ASAL, this is rarely the case (Smeins et al. 1976; West et al. 1984; Westoby et al. 1989; Omar 1991). In the ASAL, including Mediterranean climate regions (Naveh 1988), it seems more reasonable to seek a return to an intermediate or alternative steady-state, such as a quasi-metastability that can be created and maintained by continual but relatively light human disturbance. Some disturbances are, of course, created in the absence of people, such as natural fires, hurricanes, volcanos, epidemics, but these appear to be rare in the ASAL. This still implies introducing new attitudes, insights, and-above all-enlightened management techniques to local people (Goodloe 1969; Lange 1969; Janzen 1986), particularly if indigenous ecosystems have already crossed one or more thresholds in the course of their degradation. Threshold of Irreversibility. The concept of “thresholds” of environmental change is well established in ecology (Holling 1973; May 1977; Wissel1984), and has recently been applied to range management as well (Friedel 10 Restoration Ecology MARCH 1993 Restoration and Rehabilitation. I. 1991; Laycock 1991). Still, “thresholds of irreversibility” are not easily detected or quantified, but once having passed through one, most ASAL ecosystems apparently cannot cross back without interventions designed to correct the specific changes that led to the r threshold being crossed. For example, reconstitution of seed banks might be needed, or the restocking of soil organic matter and microorganisms that promote higher plant establishment and growth. Where truncation of upper soil layers, sedimentation, salinization, or other processes have drastically modified surface and sub-soils, reconditioning of soils or reactivation of their hydrological functioning may be required.