Rehabilitation of Degraded Ecosystems in Central Chile and Its Relevance to the Arid "Norte Chico"

Home , Jubaea, Maytenus boaria, Ovalle, Prosopis tamarugo, Schizanthus

Revista Chilena de Historia Natural 66: 291-303, 1993 Rehabilitation of degraded ecosystems in central Chile and its relevance to the arid "Norte Chico"

Rehabilitaci6n de ecosistemas degradados de Chile central y su relevancia para el "Norte Chico" árido

CARLOS OV ALLEl, JAMES ARONSON2, JULIA A VENDAÑO, RAUL MENESES4 and RAUL MORENO

1Estaci6n Experimental Quilamapu, INIA. Casilla 426, Chillán, Chile. 2 Centre L. Emberger, C.N.R.S., B.P. 5051-34033 Montpellier, France. 3Estaci6n Experimental Cauquenes, INIA. Casilla 165, Cauquenes, Chile. 4Estaci6n Experimental Los Vilos, INIA. Los Vilos, Chile. 5Facultad de Ciencias, Universidad de La Serena. Casilla 599, La Serena, Chile.

ABSTRACT

An ecosystem rehabilitation project in the subhumid 7 Region of central Chile is described, with a three-tiered research and development (R & D) approach that addresses the structure and functioning of soils and vegetation and aims, in the long-term, at a full scale transformation of the region into a mosaic of agroforestry systems and natural ecosystem reserves. The important role of native and carefully-screened exotic nitrogen-fixing legumes in "jumpstarting" the rehabilitation process is underlined. We then suggest that a similar R & D approach could be applied in the arid "Norte Chico" region of northern Chile as well. Apart from immediate interventions, emphasis is placed on revised management of land and water, flora and fauna through the replacement of "artificial negative selection" by a strategy of "positive selection". Also noted are the numerous gaps in current knowledge and the grinding socio-economic realities that hinder any rapid realization of our optimistic scenario. Key words: Ecological rehabilitation, arid and semiarid land ecosystems, nitrogen-fixing legumes, bioresources, artificial negative selection, positive selection, Chile.

RESUMEN

Se describe un proyecto sobre rehabilitaci6n ecol6gica en la regi6n subhumeda de Chile central. El enfasis ha sido puesto en el mejoramiento de la fertilidad de Ios suelos, inducido por las leguminosas leiiosas y herbaceas nativas y por la introducci6n de plantas ex6ticas fijadoras multiprop6sito, cuidadosamente seleccionadas por su mayor eficiencia de fijaci6n y aportes a la producci6n de fitomasa. Se sugiere que un programa similar podria ser válido para la regi6n árida (Norte Chico) del país. Además de algunas intervenciones inmediatas y a largo plazo se propone una revisión de sistemas de manejo de suelos, agua, flora y fauna utilizando una estrategia de "selecci6n positiva" en vez de la "selecci6n artificial negativa" que domina actualmente. Asimismo se mencionan la falta de conocimiento en numerosos aspectos del manejo de Ios recursos naturales renovables y Ios obstáculos socioecon6micos que impiden la actualizaci6n rapida de nuestro escenario optimista. Palabras claves: Rehabilitaci6n ecol6gica, ecosistemas áridos y semiaridos, leguminosas fijadores de nitr6geno, recursos biol6gicos, selecci6n artificial negativa, selecci6n positiva.

INTRODUCTION probably no longer feasible (Sprugel 1991). Nevertheless, ecological rehabilitation that In the arid, semiarid and subhumid regions takes indigenous ecosystems and landscapes of central and northern Chile, virtually all as working models, but emphasize functiona- terrestrial ecosystems have been disturbed and lity and productivity over regaining former degraded (Mufi.oz Schick 1975, Bonilla 1977, species inventories appears a promising Bahre 1979,Gast61979,Balduzzietal. 1981, strategy to fight continued desertization and Fuentes & Hajek 1978, 1979, Fuentes & rural poverty. Rehabilitation and restoration Prenafeta 1988, Etienne et al. 1983, 1987, have in common the fact that they take inde- Armesto & Pickett 1985, Gast6 et al. 1990) to genous ecosystems as their model (Fig. 1) the point that a full restoration of their structure while the more common land use which we and function to a presumed original state is call "reallocation" assigns new use(s) to a site

(Received 13 july 1992; accepted 16 November 1992.) 292 OVALLEET AL.

----RESTORATION---•1-REHABILITATION-1---REALLOCATION --+-

ORIGINAL NEW ECOSYSTEMS ~ ~ ECOSYSTEMS

LOCAL LOCAL AND/OR REVISED SPECIES EXOTIC SPECIES MANAGEMENT TECHNIQUES

REINTRODUCTION OF PLANTS AND ANTHROPIC MICROORGANISMS; PERTURBATION REVISED MANAGEMENT TECHNIQUES

DEGRADATION REVERSIBLE J DEGRADATION IRREVERSIBLE WITHOUT MASSIVE INTERVENTION

~ DISTURBED/ ECOSYSTEMS Fig. 1: Schematic representation of ecosystem degradation and alternative responses of restoration, rehabilitation or reallocation. Modelo esquem,tico de la degradaci6n de ecosistemas y de las respuestas altemativas de restauraci6n, rehabilitaci6n o realocaci6n. that does not necessarily bear any relation- Mimosoideae) and a large variety of native ship to the indigenous ecosystem's structure and exotic annuals (Ovalle et al. 1988, 1990). or functioning (Aronson et al. 1993). The resulting pseudo-savannas (locally known In this article, we describe an ongoing re- as "espinales") provide the framework for habilitation project in the subhumid portion agriculture and animal husbandry for ea. of the mediterranean-type climate zone of 300,000 people in the area between Santiago central Chile, and discuss its possible relevance and Chillm. Although receiving 350-700 mm to part of the arid region of northern Chile, mean annual precipitation, this area is func- the "Norte Chico". Given the far less deve- tionally arid because annual rainfall is high- loped agricultural infrastructure in the Norte ly variable in amount and efficiency and is Chico, and the need to develop new crops and concentrated in the coldest months of the year. new approachs, we also highlight the numerous Primary productivity and succession is also underexploited and, above all, ill-managed severely inhibited by chronic disturbance plant and animal resources of the Chilean arid and lack of regeneration of most perennial zone. species. It has been estimated that only about 25% Current status of the espinales of the espinales in the 7tll and 8tll Regions, and about 30-35% in the 5tll and 6tll Regions, Over 2,000,000 ha in the subhumid portions possess and adequate tree stratum to allow for of the "secano interior", i.e., the unirrigated gradual improvement through the revision of portions of the Central depression of central management techniques alone (Ovalle et al. Chile, are dominated by a synanthropic for- 1988, 1991). In a cartographic study (Ovalle mation consisting of the nitrogen-fixing et al., in review b) carried out on 23,000 ha legume tree Acacia caven Mol. (Fabaceae: near Cauquenes, in the 7tll Region, only 2% of REHABILITATION OF DEGRADED ECOSYSTEMS IN CENTRAL CHILE 293

the study area could be classified as having N2-fixing microsymbiont "couples" to espi- espinales in "very good" condition on the basis nales can increase the amount of total and of tree density and height. Fully 44% of the available nitrogen, and beneficial microflora remaining espinales were classified as de- and fauna, in shallow and deep soils, increase graded or very degraded. Only 5% of the study water infiltration to deep soil layers, and pro- area had remnants of native matorral, and these mote the establishment and development of were all badly degraded. (fhe rest of the study other plants of all types (Ovalle et al. 1990, area has been reallocated to rainfed cerealcul- 1991, in press, in review a). ture or vineyards wherein all trees are syste- Thorough revision of water use and resource matically removed.) management techniques will also be required Apart from the nature of their arboreal to keep the rehabilitation process moving and stratum, the productivity and biodiversity of to achieve a tightening of nutrient cycles such the espinales is blocked by the condition of as generally characterizes mature, stable their soils. Most espinal soils are so badly ecosystems (Odum 1969, Vitousek & Reiners degraded, depleted and compacted that they 1975). Yet given the crucial role of people in represent a serious limitation to water infil- the rehabilitation process, we believe that tration, nutrient cycling and plant growth, even demonstrating the great diversity of native and for Acacia caven. Current plant and animal non-native but well-adapted bioresources production levels in the espinales are conse- available is the first step to achieving social quently very low as compared to that of other and economic change. At the same time, mediterranean-type climate areas with similar however, the potentially dangerous conse- rainfall regimes (Serrano & Jara 1975, Crespo quences of the intentional introduction of fast- 1985, Ovalle et al. 1990, cf. Whitford 1986, growing woody plants and their associated 1988). microorganism must be carefully monitored so as to avoid the inadvertant introduction of Espinal research program yet more exotic weeds. To obtain farmers' interest and willingness Well-adjusted livestock management techni- to cooperate, we describe our program in three ques can, of course, improve productivity stages. First, in the short term, we seek ways in central Chilean espinales, independently of and means to manage existing plant resources direct manipulations of soils or vegetation. for maximum productivity. This primarily For example, when animal stocking rates were takes the form of revised management of es- re-adjusted in accordance with annual fluc- pino, the dominant species of Chilean espi- tuations in primary productivity in a well- nales. However, the introduction of selected managed espinal near Cauquenes, both pasture lines of the well-known annual legume, and animal yields increased dramatically "hualputra" (Medicago polymorpha), with (Ovalle 1986, Ovalle & Avendafio 1987). A selected strains of rhizobia (Del Pozo et al. significant increase in ecosystem yield to the 1989a, b, c, Herrera et al. in review) should farmer was thus achieved through the simple also be rapidly assimilable by local farmers. If revision of management techniques (A vendafio we can demonstrate that local ecotypes of this et al. 1990, 1992). annual medic increase wheat yields in a crop Over and above livestock management rotation, many farmers are likely to adopt techniques, however, our research and deve- them just as they have in other arid or semiarid lopment (R & D) program addresses soil and rnediterranean climate regions (Puckridge & vegetation rehabilitation directly. The major French 1983, Chatterton & Chatterton 1984, tool being tested for this is the experimental Crespo 1985). introduction of a variety of Nrfixing plant/ Second, in the mid-term (5-10 years), we microorganism "couples" in representative propose that introducing Nrfixing fodder sites from Cauquenes, in the subhumid zone, shrubs such as tagasaste (Chamaecytisus pro to Quebrada El Tangue, near La Serena (4th liferus subsp. palmensis), from the Canary region), in arid zone (Fig. 2). We hypothesi- Islands (Snook 1982, Ovalle et al. 1990, in ze that the introduction of compatible and press), can help create a "mixed espinal" of appropriate woody and herbaceous legume/ greater productivity and stability than the 294 OV ALLE Ef AL.

ARID ZONE

3~ SEMIARID ... ZONE Tierras Blancas , ', I I e I \ SANTIAGO \_;..... _/

/ I PLANTING SITES I I.A. I JJ.. Trees and shrubs I • Tagasaste only ~Cauquenes'•* I * Annual medic ..... , illan_ ... , I . .I San Miguell I I I .. HUMID \, Santa/Lucia ZONE 0 100 200Km ...... _;/

Fig. 2: Sites of main experimental plantations in central Chile. Sitios de las plantaciones experirnentales principales en Chile central. monospecific espinal currently found in cen- the Chilean matorral or other lands. Current tral Chile (Ovalle et al. 1990, 1991). trials include 10 Chilean and non-Chilean Long-term (10-25 years), we envision the provenances of Acacia caven (espino ), several incorporation of long-lived, prolific cultivars Argentinian and Chilean provenances of of espino and algarrobo (Prosopis spp.) as well Prosopis alba, P. chilensis and other algarro- as other multipurpose trees and shrubs from bos, the native fodder trees belloto (Beil- REHABILITATION OF DEGRADED ECOSYSTEMS IN CENTRAL CHILE 295 schmedia spp.) and maiten (Maytenus boaria) even in favored river vallies such as the Co- (Ovalle et al. in review a, b, in press). Even piap6, seem feasible. New approaches are more than shrubs or annuals, it is these large, needed if sustainable development has to deep-rooted trees that can do the most to re- proceed. habilitate soils in a profound and long-lasting In the mid-1970s, no less than 52% of the way. ea. 3.5 million ha of the 4th Region was used Many stages of R & D are thus envision- for rainfed agriculture of livestock husbandry, ed for vegetation and soil rehabilitation. Ho- and 3% was under irrigated agriculture. Of pefully, greater diversification of livestock the remaining, fully 44%, or 1.57 million ha, herds will take place as well as enriched soils were considered "sterile", and of no use and plant communities, as local people assume whatsoever (INE 1976, cited in Az6car & the role of agm-ecosystem manager of "mixed" Lailhacar 1990). This latter statistic refers espinales. Incorporation of these new plant primarily to former rangelands rendered species into existing land use systems will, of useless through overcutting and overgrazing, course, require considerable rural extension and neglects the possibilities of ecological work. Even so, this scenario may seem overly rehabilitation. In a detailed study carried out optimistic, but we see no other alternative to on 300,000 ha in the 4th Region, 59% of the continued degradation in the depressed "secano area studied was found "extremely" degraded interior''. Moreover, we propose that a similar (Etienne et al. 1978). In the last 15 years the R & D approach could be applied, with certain situation has only gotten worse. Althought a modifications, in northern Chile as well. number of basic and applied ecological studies have been carried out in the 4th and 5th regions Current status of the 'Norte Chico' (Bonilla et al. 1971, Cosio & Demanet 1984, Az6car & Lailhacar 1990, Gast6 et al. 1990), From La Serena north, the coastal and inland desertization and ecosystem degradation valley desert flora of Chile belongs to a bio- persist (Fuentes & Hajek 1978, 1979, Etienne geographic region that extends all the way to et al. 1982, 1983, 1987, D'Herbes 1988). Less the Peru-Ecuador border (Rauh 1985, Rundel than 0.1% of the 18 million hectares of the et al. 1991). This vast region is divided bet- Norte Chico are currently cultivated, and un- ween the "Norte Chico" (the area lying north restained grazing and fuel wood harvesting of the La Ligua-Petorca line to just south of continue to be the major activities throughout Chafiaral and the Norte Grande (Chafiaral to the remainder of the area. the Peruvian border) (Mufioz Schick 1985). Saltbush (Atriplex spp.) plantations (Oliva- Unlike many desert areas, the hyperaridity of res & Gast6 1981, Lailhacar et al. 1981) and the Atacama and southern Peruvian deserts limited reforestation in the Pampa del Tama- appears to date back to the Middle Miocene or rugal (Habit 1981) are just about all that has late Eocene (Rundel et al. 1991). been attemped in the way of agro-ecological Historical records indicate that the vallies rehabilitation or restoration in northern Chile. of both the Rfo Huasco and Rfo Copiap6 once Results of these endeavors are only partially supported dense stands of phreatophytic trees. satisfactory. Indeed, Copiap6 was once known as San Francisco de la Selva because of the extensive Research proposals for the N orte Chi eo stands of trees which covered the valley (Klohn 1972, cited in Rundel et al. 1991). However, In our opinion, a similar R & D program to throughout the area, people (and mining that we are pursuing in central Chile could companies) have dramatically reduced woody be developed in the Norte Chico. The four vegetation cover and lowered watertables essential features are: 1) the use of indigenous (Lloyd 1976). Given the degradation which ecosystems as models for sustainable deve- has taken place, it appears unlikely that full lopment, 2) rehabilitation of degraded soils, restoration of indigenous ecosystems could be 3) the development of full potential of native achieved without massive inputs of energy plants and animals and 4) the use of a three- and capital. On the other hand, little, further tiered approach to maintain local farmers' and development of conventional irrigated crops, pastoralists' interest during early stages. 296 OVALLEET AL.

As a result of aridity, ecosystems in the and the worst last. Artificial negative selection Norte Chico are probably less disturbed and is the leading, anthropogenic cause of genetic natural resources overall less depleted than erosion at or below the species level. When its those of central Chile. Prospects for their consequences are evaluated at higher levels, rehabilitation may in fact be greater in the negative selection can be seen to accelerate long run. Most native plants and animals are rural exodus while it contributes to the degra- still present, and many of these show very dation of ecosystems and fragmentation of high economic value (Rodrlguez et al. 1984, landscapes. We will now attempt to elucida- Mut\oz Schick 1985, Aronson 1990). It must te all of these points by the use of stylized be emphasized that without substantial sub- "before" and "after'' drawings (Figs. 3, 4). sidies (energy, water and capital), the reha- Figure 3 gives a stylized image of a small bilitation process will be slow in the arid N orte village of the arid Norte Chico, well away Chico. Yet the potential role of native nitro- from the big centers of current development gen-fixing "couples", and of mechanical in the major river vallies (the Copiap6, Huasco, emendations to soil surfaces in the speeding Elqui, Limarl and Choapa). Apart from in- up the process should not be underestimated. dividually owned agricultural plots, livestock As mentioned, northern Chile boasts many -mostly goats- are pastured on communally valuable natural products, including animal owned lands. The crevised, eroded soils are and vegetable as well as the better-known mi- the result of badly managed water sources, neral resources. Yet very few of the faunal and the fact that much of what fresh water and floral riches are incorporated into existing exists upstream is diverted for mining and production systems nor even considered as urban centers elsewhere. Fig. 3 also shows potential resources in current R & D programs. that many formerly cultivated fields have been Some of these need to be developed rapidly so abandoned. Native fauna and flora outside as to show local people the possibility of of cultivated areas are also impoverished in alternative strategies for gaining a livelihood. this depressing landscape, due to uncontrolled Finally, mechanical interventions to improve hunting, trapping and ill-managed grazing by soil fertility and to reduce or channel surface goats- all examples of artificial negative se- run-off during rain events should be attempt- lection. ed while alternative water sources should also The principal product, goat's milk, is of be developed. For example, reactivation of the very poor quality. The empty corral and the physical and hydrological functioning of absence of animals near the village suggest degraded vertisols in northern Cameroon has that even goats must wander far afield to find been achieved by interventions such as pasture, just as the villagers themselves must "pitting", plowing in of annual grasses, and travel further and further every week to find the creation of 50-200 m2 water-catchment firewood for cooking and heating their homes. basins that force water to infiltrate more or Furthermore, no infraestructure exists for im- less evenly (Masse 1992, Aronson et al. in proving the quality of the goat's milk produced. review a). Nevertheless, the critical obstacle The village gets smaller each year as young is perhaps a matter of attitude about the use of people leave the area, looking for work in biological resources. mines and the cities, or else to the rapidly "Artificial negative selection" (Burkart developing agricultural centers in the irrigable 1976, Aronson 1990, Aronson et al. in review river vallies. There seems little hope for re- b) refers to the nearly universal process versing current ecological and socio-economic whereby most people (and animals) exploit trends. plants and animals in reverse order to that In Figure 4, however, we see the same which would be in their own longterm interest. village and surrounding landscape as it could Instead of preserving the "elite" individuals appear in the future. Offstage, the permanent of wild populations they exploit -which river valleys that cross the arid region continue practise is called "positive selection"- most to have the highest concentration of people people systematically remove first the largest, and export-based agriculture in the region. most valuable and most palatable trees, shrubs However, rational watershed management at and grasses (and animals), the next best next, the village and landscape level, plus improvi- REHABII.lT ATION OF DEGRADED ECOSYSTEMS IN CENTRAL CHILE 297

.. ; .··, .. -..." •..J, <;·:: --~-~~· .; ...c·~- ... ~.:;. .~: -;.· -

Fig. 3: Present (simplified) landscape of a small river valley village in the Norte Chico showing highly disturbed ecosystems and bioresources suffering from "artificial negative selection". El paisaje actual (pero simplificado) de una comuna o pueblo tradicional en el None Ollco, con evidencia de ecosistemas perturbados y recursos naturales muy degradados por la "selecci6n artificial negativa".

Fig. 4: The full potential for biodiversity and reintegration for the same landscape shown in Fig. 3 once agriculture and livestock husbandry are linked to a landscape and ecosystem approach including a strategy of positive selection. El potencial del mismo paisaje encontrado en la Fig. 3 cuando loa sistemas agropecuarios funcionan en un programa de desarrollo holfstico del ecosistema y del paisaje incluyendo una estrategia de "selecci6n positiva". ded soil fertility allow the development of with revised management of natural resources, sustainable agriculture and animal husbandry, including wildlife, could vastly improve the even in smaller river bains, such as the one attractiveness of the region for inhabitants and, depicted here. These improvements, combined one day perhaps, vacationing visitors. 298 OV ALLE Ef AL.

Aoristic and faunal biodiversity as well as huilli (Leucocoryne spp.), pajarito (Schizanthus agroecological productivity are on the rise in spp.) and terciopelo (Argylia radiata) could be Fig. 4, as desert-adapted native crops and fod- grown in small plots below the village. The der and fuelwood plantations reduce pressure spectacular flower stalks of these native plants on wild plants and animals. Domesticated li- are currently sold to tourists in spring and vestock herds are mixed (e.g., sheep, goats are summer along roadsides, but could also be now joined by llamas and alpacas); grazing transported to city markets by growers, and of wild vegetation is closely managed and even possibly flown out of La Serena or supplemented by agricultural byproducts and Iquique to flower markets around the world. other fodder resources collected and brought Aower and bulb plots could be irrigated by to animals, e.g., chafiar (Geoffroea decorti surface-channeled run-off water to increase cans) and algarrobo (Prosopis spp.) pods; pa- yields. In addition, deep wells should be ex- ramela (Adesmia spp.) and pintoa (Pintoa ploited to provide extra water to flower plots chilensis) foliage. All of these species except in critical periods of growth. Species tolerant pintoa are biological nitrogen-fixers and can of slightly saline ground water could be se- thus improve soils as they provide direct eco- lected and developed. nomic services. Selected cultivars of the chagual (Puya spp., Alfalfa grows and produces well in the Bromeliaceae) could be grown in the Norte Norte Chico and, given adequate water mana- Chico with little or no irrigation (Fig. 4, left gement, it could be an important complement foreground), as a novel vegetable crop simi- to other fodder resources. A three-tiered ap- lar to hearts-of-palm. Native columnar cacti, proach would be quite suitable here, such as including quisco (Eulychinia spp.) and copao has been developed in the espinales further (Trichocereus chilensis and T. coquimbanus) south (see above, and Ovalle et al. in review provide delicious fruit (Mufioz Schick 1985, a, 1991), since alfalfa could be readily in- Aronson 1990), and selected, heavy-bearing serted into existing schemes, while establish- individuals could be propagated vegetatively ment and integration of trees and shrubs will and planted in appropriate sites, just as has certainly take much longer. (Selected ecotypes been done for Mexican Opuntia varieties, and of hualputra (Medicago polymorpha) could is now being attemped for some Mexican co- also be tried in the Norte Chico.) lumnar cacti as well (Nerd et al. 1989). Furthermore, efforts must be undertaken Higher up on the slopes (in Fig. 4), wild to enhance milk quality in the region, starting chinchillas are once again abundant, along with improved sanitary conditions for the with native raptors and avifauna. With go- animals. New technologies would allow the vernment subsidies, experimental chinchilla processing of cheese and other milk products farming should be tested, just as Echegoycin more suitable for transport and conservation (1923) proposed 70 years ago. The endemic in hot, arid lands than fresh milk. Such rela- shrub Balsamocarpon brevifolium (algarro- tively simple innovations would enable small billa), whose pods are the chinchilla's favorite communes to insert their produce into a mo- food, could be planted nearby with little or no dem commercialization and marketing scheme, need for irrigation (Aronson 1990). Sufficient suppling nearby towns and rural markets. Gi- large shrubs of this species survive in the Norte ven supplementary veterinary services, as well Chico and Norte Grande to provide plentiful as R & D on the landscape-scale integration seed for propagation. Alternatively, chinchi- of irrigated alfalfa and some of the other fodder lla for production could be restricted to the resources mentioned above, and the institution large areas of natural flora and fauna reserves, of positive selection of wild plant resources, while their exploitation would be rigorously improved, enlarged herds could be managed restricted to members of local communes. In by rural communes to produce significantly these reserves, other native fauna to be pro- increased milk and milk product output in the tected include not only native camelids (vicu- Norte Chico. fla, alpaca and guanaco), but also Pudu pudu Native spring flowers and bulbs, such as (pudu) and the large terrestrial rhea, Pteroc afiafiuca (Rhodophiala spp.), azulillo (Pasithea nemia pennata garlepi (flandu petiso or "os- spp.), mariposa del campo (Alstroemeria spp.), trich of the cordillera"). This latter species REHABILITATION OF DEGRADED ECOSYSTEMS IN CENTRAL CHILE 299 might well be of interest for animal husbandry for fruits, wine and vegetables. We see no for meat, eggs, feathers and skin. reason why this could not be done for native Arid land foresters should initiate forest flowers as well. reserves of guayacm (Porlieria chilensis), Mid-term, nitrogen-fixing, drought- and carbonillo (Cordia decandra), Krameria, salt-tolerant casuarinas (e.g., C. cunningha Acacia, chafi.ar, Prosopis well away from the miana and C. equisetifolia), could be used as village. These trees could be harvested on a windbreaks around flower plots and simple long-term (25-100 years) rational basis, or else diversion systems or catchment basins could managed for wildlife refuges, watershed pro- provide the necessary irrigation to insure an tection and, ultimately, ecotourism use. In ei- annual harvest, irrespective of fluctuations in ther case, their value to the village and the annual rainfall. Low-energy technology exists region could be great, given adequate attention for growing proven drought-tolerant firewood to selection and propagation of elite genetic trees (e.g., coppiced Acacia, Eucalyptus, material, conservation of viable populations, Casuarina, and Tamarix aphylla) in rainfall- and appropriate silvicultural and post-harvest harvesting catchments (Lovenstein et al. 1991, product development. Such reserves would Zohar et al. 1988, Aronson et al. 1987) could amount to a landmark example of "positive be adapted to replace the destructive, anarchic selection" of native bioresources. collection of firewood from dwinling populations in the distant hills (more artificial nega- R & D Timetable tive selection). Concurrently, a broad-reaching plan for the conservation and anagement of It goes without saying that the higly optimistic endangered native plants (see Appendix) and vision of agroecological diversity depicted here animals should be established during this phase. can not be achieved in a short time, nor witho- For example, the handsome endemic tree ut considerable investment in research and guayacm (Porlieria chilensis; Zygophylla- development (cf. Felger & Babhan 1978, for a ceae), of important economic for woodworking comparable scenario based on Sonoran desert of various small items sold to tourists (Aronson bioresources). Some readers may even consider 1990), is badly overexploited throughout its this scenario too far removed from current range and in clear danger of extinction reality to merit serious attention. Yet, just as (CONAF 1985). Productivity and quality of in the case of the espinales further south, we guayacm wood could be much improved if argue that a short-, mid- and long-term master the trees were protected, managed properly plan is needed in the Norte Chico, and that if and allowed to reach decent size before har- an optimistic approach is not adapted as a vesting. Ideally, replanting with selected ger- long-term strategy, nothing important will ever mplasm would be combined with watershed really change. protection and soil conservation schemes on To begin, well-known arido-crop shrubs steep slopes. such as the endemic Atriplex repanda (and Similarly, algarrobos (especially Prosopis other related species) could increase fodder alba var. alba) and "elite" individuals of chafiar productivity in the short-term (Lailhacar et al. (Geoffroea decorticans) could be put to much 1981, Olivares & Gast6 1981). Pitting and more use as food, fodder and agroforestry trees other surface treatments as well as more ela- than they are at present, particularly where borate rainfall-harvesting systems should be phreatic water tables are high (Felker 1979, tested to increase infiltration and plant pro- National Academy of Sciences 1980, Ovalle ductivity in concentrated areas. In our opinion, et al. 1990). These and other nitrogen-fixers at least a dozen native bulb species could be could -in the space of 10 to 20 years- have immediately put into experimental cultivation very significant impact on the mineral and as cash crops, while selection and genetic im- organic matter contents and microflora of provement could be initiated concurrently. It degraded soils. Reintroducing and protecting may be objected that a cash market and export native trees and shrubs should also have bene- economy does not at present exist in the region ficial impact on associated herbaceous veg- outside of the most favored river vallies. Yet a etation serving as pasture for domestic live- market infrastructure does already exist nearby stock. 300 OV ALLE ET AL.

In the realm of agro-industry, several native Camelids, or course, would supplement cattle, plants of northern Chile have unusual che- sheep and goats, but also perhaps degli (Oc micals of potential use pharmaceutically or todon degu) nutria (Myocastor) and wild industrially. For example, two native shrubs ostrich (Pterocnemia pennata garlepi). Re- of northern Chile, Grindelia tarapaca and G. maining populations of the endangered, and glutinosa (Asteraceae), yield labdane di- non-domesticable fauna of the southern An- tetpenoids, useable as tackifiers, glu, varnish, des should be just as rigorously protected as insecticides, etc. (B.N. Timmermann & E. the rare and endangered plant species. Once Fuentes personal communication). The related populations build back up to appropriate sizes, G. camporum of North America has already some of these native animals could then be being planted in pilot scale test plots in Aus- harvested on a rational basis. More ambi- tralia. tiously, R & D could be undertaken to examine Long-term, new (and modified ancient) the viability of raising some of these animals methods of harvesting surface runoff (Fig. 4, domestically in the region. As in export-based right hand hillside) as well as seawater agri- agriculture and agro-industry, quality rather culture and forestry (Fig. 4, righ-hand fore- than quantity should be emphasized. ground) should be tested in northern Chile Finally, it will be necessary to develop ra- and, if successful, used to supplement meagre, tional systems of water management in the erratic supplies of rainfall and dwindling sup- region. Until water supply for people, crops plies of non-salty ground water. and animals is better controlled and appor- tioned, virtually no aspect of our scenario is feasible. Whether communal organization RESEARCH GAPS AND REAL WORLD OBSTACLES will continue or be entirely replaced by private enterprises is a related issue to be addressed, Technical gaps and will obviously have great impact on any new water conservation and utilization Interventions are urgently needed to restore schemes. lost nitrogen and organic matter supplies as well as microorganisms and detritivore pop- Financial gaps and obstacles ulations in the soil. Yet, it will be objected, aridity and unpredictability of rainfall are One other critical need is to identify sources major growth limitations for soil biota. Indeed, of funding for the needed research and de- for northern Chile and other ASAL, it is ne- velopment. Given their precarious subsistance- cessary to find appropriate and effective level economies, and the highly unpredictable rhizobia! and mycorrhizal inoculants for use environment in which they live, local people with plant introductions in degraded, arid soils. can not and will not invest in unknown me- But we argue that technical problems are thods, crops or domesticates. Someone else less serious here than psychological, socio- will have to pay for the R & D. economic and cultural ones. Agronomic and post-harvest handling Socio-cultural obstacles problems will of course need to be addressed for each new crop or other proposed innova- Indeep the major obstacles to realization of tion in northern Chile. But, in our opinion, the our scenario, or any other alternative future potential export value of the novel desert fruits, for the Norte Chico, may be social and cultu- vegetables and cut flowers mentioned above ral rather than technological or financial. A is very high, provided that sufficient quantities highly precarious subsistance economy could be produced and that an adequate in- currently prevails; how to make the transition frastructure were developed to assure a steady towards a marlcet economy at least partially flow to regional markets. Thus, funding for R based on cash crops is the main problem to be & D on these new crops should be obtainable. addressed. Poverty-stricken people have Just as crops would be more diversified in understandably great difficulty in conceiving our optimistic scenario, so would livestock the cultivation of products (fur, feathers, bulbs production diversify in the Chilean ASAL. and cut flowers) that are not of immediate REHABILITATION OF DEGRADED ECOSYSTEMS IN CENTRAL CHILE 301

practicality to themselves. However, we argue 1983, D'Herbes 1988, Az6car & Lailhacar that only through greater insertion into regio- 1990). Thus, in northern Chile firewood and nal, national and one day, international, fuel must be provided locally even while markets can the quality of life in these com- efforts could be made to convince decision- munes be sufficiently raised as to initiate makers in Santiago to subsidize kerosene and healthy economic development and allow kerosene stoves for villagers in the arid regions ecosystem rehabilitation at the same time. Yet so as to reduce pressure on standing biomass. it is essential that the farmers and pastoralists Similarly, goats must be tolerated in the themselves not become the victims of short run, because local people simply will commercial middlemen nor the pawns of the not replace them with other livestock until vagaries of foreign commodity speculators. It they are completely convinced it is a good is true that past efforts to develop tomato and idea economically. Indeed, well-managed goat cumin crops in the region have not led to herds are not necessarily part of the problem. dramatic influxes of cash (M. Etienne, pers. It is only when the husbandry of goats (and comm.). However, we suspect this is because other livestock) is completely anarchic that they were not part of a community-based R & their presence represents and impediment to D plan, but rather were developed with private integrated landscape and ecosystem planning, capital from outside the region. If successful, conservation and development. the influx of cash deriving from cash crops would raise confidence and willingness to seek insertion into a regional marketing network. DISCUSSION At the same time, new modes of production obviously must be compatible with existing In the Norte Chico, as in central Chilean cultural and sociological patterns (Etienne et al. espinales, local habits and practises will have

APPENDIX

Partial list of vulnerable and rare plant species of the arid and semiarid regions of Chile (CONAF, 1985) with clear economic potential. A large number of ornamental flowering geophytes are not included Lista parcial de especies de plantas raras y vulnerables de las regiones bidas y semi,ridas de Chile (CONAF, 1985) con claro potencial econ6mico. No se incluye un gran nUmero de geofitas con flores omamentales

Species (common name) Regions Uses

VULNERABLE TO EXTINCTION

Beilsc/JrMdia berteroana (Gay) Kos. fodder B. miersii (Gay) Kos. (Belloto del None) V, VI,M.R.1 fodder Carica chile11Sis (Planch ex DC) Solms.-Laub. (Palo gordo) IV, V fruit Cordia decandra h. et A. (Carbonillo) ill, IV fuel wood KratMria cistoidea H. et A. (Pacul) ill, IV fodder Porlieria chile11Sis Johnst. (Guayacm) IV-VI,M.R. fine wood Puya coquimbensis Mez. (Chagual de Coquimbo) IV vegetable P. venusta Phil. (Chagualillo) IV, V vegetable

RARE

Athsmia balsamica Ben. & Colla (Paramela de Puangue) V fodder A. resinosa Phil. (Paramela de Til-Til) V,M.R. fodder Pintoa chilensis Gay (Pintoa) ill, IV fodder Jubaea chilensis (Mol.) Baillon (Palma chilena) IV, V,M.R. liqueur, oil, thatch

t Metropolitan Region, around Santiago. 302 OV ALLE Ef AL. to change before new scenarios can be enacted. ARMESTO JJ & STA PICKET (1985) A mechanistic approach to the study of succession in the Chilean matorral. New management techniques and new stra- Revista Chilena de Historia Natural 58: 9-17. tegies must be developed. Human populations ARONSON J (1990) Desert plants of use and charm from and grazing pressures must be maintained northern Chile. Desert Plants 10: 65-74,79-86. ARONSON J, C OVALLE & J AVENDANO (1991) Early at appropriate levels and a balance between growth rate and nitrogen fixation potential in 44legume communal and privately-owned lands must be species grown in two soil types in central Chile. Forest sought as well. Ecology & Management 47: 225-244. ARONSON J, C FLORET, E LE FLOC'H, C OVALLE & R Some valuable and readily transferable R PONT ANIER (1993) Restoration and rehabilitation of & D has been carried out in various drylan degraded ecosystems: I. A view from the South. Res- regions, yet much more is needed to reverse toration Ecology 1: 8-17. ARONSON J, C FLORET, E LE FLOC'H, C OVALLE & R current trends of desertization and ecosystem PONTANIER (in review a) Restoration and rehabili- degradation. Both in the espinales of central tation of degraded ecosystems. II. Case studies in cen- Chile, and the Norte Chico, a landscape and tral Chile, southern Tunisia and northern Cameroon. Restoration Ecology. . ecosystem approach is needed. Since poverty- ARONSON J, C OVALLE & J A VENDA:Jil"O (in review b) bound rural people and fragile biotic and Espinal rehabilitation in central Chile. II. New models abiotic resources must be taken into account, and paradigms. Agriculture, Ecosystems & Environ- ment. productive agroecological steady states must AVENDA:Jil"O J, C OVALLE & A DEL POZO (1990) Pasto- be sought. However, from a purely ecological reo de Hualputras con ovinos. Informe Tecnico 1989- point of view, it seems clear that maximum 1990. Area de Producci6n Animal. Estaci6n Experi- mental Quilamapu, Chillan, Chile: 302-307. protection of resources and ecosystem stability AZOCAR P & S LAIHALCAR (eds) (1990) Bases ecol6gi- need to be fostered as well. We are of course cas para el desarrollo agropecuario de la zona de clima aware of the very important obstacles stand- mediterraneo arido de Chile. Terra arida (Chile) 8: 221-301. ing in the way of realization of the optimistic BAHRE CJ (1979) Destruction of the Natural Vegetation of rehabilitation scenario presented here, but we North-Central Chile. University of California Press, believe it is one of the roles of researchers to Berkeley. BONILLA S (ed) (1977) Estudio de caso sobre la deserti- propose alternative futures, even if the current ficaci6n: Regi6n de Combarbala, Chile. Proceedings situation leads politicians, economists and UNESCO Conference on Desertification, Nairobi, other "experts" to doubt the feasability of their Kenya. INIA. Santiago. BALDUZZI A, R TOMASELLI, I SEREY & R VILLA- realization. If"positive selection" and creative SE:Jil"OR (1981) Degradation of the mediterranean type bioresource management were ever to replace of vegetation in central Chile. Ecologfa Mediterrinea artificial negative selection, dramatic trans- 7: 223-240. CHATIERTON B & L CHATIERTON (1984) Alleviating formations of both ecosystems and landscapes land degradation and increasing cereal and livestock in arid and semiarid lands could result. production in North Africa and the .1.\.liddle East using annual medicago pastures. Agriculture, Ecosystems & Environment 11: 117-129. CON AF (1985) Aetas Simposio Flora Nativa Arb6rea y ACKNOWLEDGMENTS Arbustiva de Chile Amenazada de Extinci6n. Corpo- raci6n Nacional Forestal, Ministerio de Agricultura, Santiago. The authors wish to thank Juan Armesto, Mary COSIO F & R DEMANET (1984) Estudio: analisis de sis- Kalin-Arroyo, Julio Gutit~rrez, Gary Cunnin- temas caprinos de la zona mediterranea semiarida de gham, Wesley Jarrell, Wait Whitford, and all Chile. Quillota y Llay-Llay, V Regi6n. Publicaci6n de la Estaci6n Experimental La Palma, Quillota. the participants at the October 1991 La Serena CRESPO D (1985) Intensification of sheep production under Workshop, as well as Melica Mufioz Schick grazing of marginal lands of the Mediterranean region. and Roberto Rodrfguez for stimulating dis- FAO Symposium, Genova, Italy. DEL POZO A, C OVALLE & I AVENDA:Jil"O (1989a) Los cussions. We also thank Michel Etienne, medicagos anuales en Chile. I. Comparaci6n con Edouard Le Floc 'h, Henry Noel Le Houerou Australia. Agricultura Tecnica (Chile) 49: 260-267. for the constructive comment on the manus- DEL POZO A, C OVALLE & I AVENDANO (1989b) Los medicagos anuales en Chile. II. Ecofisiologfa. Agri- cript. Rene Ferris kindly drew the figures. cultura Tecnica (Chile) 49: 268-274. DEL POZO A, C OV ALLE, I A VENDA:Jil"O & P DEL CAN- TO (1989c) Los medicagos anuales en Chile. Ill. Pers- pectivas de la rotaci6n medicago-trigo en el secano LITERATURE CITED interior de la zona mediterranea. Agricultura Tecnica (Chile) 49: 275-280. ALI..EN MF (1989) Mycorrhizae and rehabilitaci6n of D'HERBES IM (1988) Analyse agro-ecologique des systemes disturbed arid soils: processes and practises. Arid Soil de production pour le developpement rural integre des Research & Rehabilitation 3: 229-241. zones arides. Chile IVil:mc Regi6n, II, Ill, IVil:me Parties. REHABILITATION OF DEGRADED ECOSYSTEMS IN CENTRAL CHILE 303

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