Dalila Serpa - Academia.edu (original) (raw)

Papers by Dalila Serpa

<p>Wildfires constitute a diffuse source of contamination to aquatic ecosys... more <p>Wildfires constitute a diffuse source of contamination to aquatic ecosystems. In burnt hillslopes, ash and sediments transported by overland flow are a source of potentially hazardous substances, like metals, posing a risk for downstream water bodies. In the present study, post-fire metal mobilization by overland flow was evaluated in 16 m<sup>2 </sup>bounded plots at a eucalypt stand in Albergaria-a-Velha (Aveiro district, North-Central Portugal) that burnt with moderate severity in September 2019. Overland flow samples were collected on a weekly to bi-weekly basis, depending on the occurrence of rain, during the first 6 months after fire. Aside from overland flow samples collected at slope scale, water and sediment samples were also collected in a fire-affected stream within the Albergaria burned catchment, to assess the contamination risk posed by the fire. Samples were collected at three sites along the stream: one upstream, one within and another downstream from the burnt area, after major rainfall events. The metals analysed in this study included, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). Results showed that most metals exhibited a peak in exports immediately after the first significant post-fire rainfall event likely due to the wash-off of the ash layer and high sediment losses, but for some elements like Zn and Cu, exports were more or less constant over time. The fire seems to have had a low impact on the water quality of the affected stream, since metal concentrations were similar between the three study sites. The quality of stream sediments, on the other hand, was clearly affected by the fire, especially after the rainy season. As fire severity and frequency is forecasted to increase in the near future due to climate changes, the results of this work reinforce the importance of water managers to define adaptative strategies to effectively protect freshwater bodies.</p>

<p&amp... more <p>Wildfires constitute a diffuse source of contamination to aquatic ecosystems. In burnt areas, the increase in surface runoff and associated sediment losses after fire, promotes the mobilization of hazardous substances, such as metals and polycyclic aromatic hydrocarbons (PAHs), posing a risk for the adjacent water bodies. In the present study, post-fire metals and PAHs export by surface runoff was evaluated in 16 m<sup>2 </sup>bounded plots in a eucalypt stand in Albergaria-a-Velha (Aveiro district, North-Central Portugal) burnt in September 2019. Runoff samples were collected on a weekly to bi-weekly basis, depending on the occurrence of rainfall, during the first 6 months after fire. The metals analyzed in this study were, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). As for PAHs, the analyses focused on the 16 compounds classified as priority pollutants by the United States Environmental Protection Agency. Both dissolved and particulate fractions of metals and PAHs in runoff waters were analysed in this work. Preliminary results suggest that metals are more likely to affect the water quality of fire-affected water bodies than PAHs, since low levels of PAHs were found in runoff waters. This work provides valuable information for water managers to minimize the risks of wildfires both to the environment and to public health.</p>

Land Degradation & Development

DITTY (Development of an information technology tool for the management of Southern European lago... more DITTY (Development of an information technology tool for the management of Southern European lagoons under the influence of river-basin runoff) (EESD Project EVK3-CT-2002-00084

Ciência Agronômica, 2007

Resumo-As zonas costeiras representam uma pequena parte da área e do volume dos oceanos. No entan... more Resumo-As zonas costeiras representam uma pequena parte da área e do volume dos oceanos. No entanto, a sua importância como interface entre a terra e o mar é enorme. Mais de 60% da população humana vive a menos de 60 km do mar e, além disso, as zonas costeiras garantem uma série de serviços essenciais à humanidade. Estes ecossistemas funcionam como um mecanismo de convergência de todas as acções levadas a cabo pelo Homem nas bacias hidrográficas adjacentes, sendo por isso necessário, no espírito da Directiva Quadro da Água-DQA-2000/60/EC (UE, 2000), considerá-las na gestão desses sistemas. Apresenta-se, neste trabalho, um conjunto de ferramentas destinadas à gestão integrada de zonas costeiras, desenvolvidas no âmbito de um projecto europeu e utilizando como exemplo o Parque Natural da Ria Formosa (Sul de Portugal). Estas ferramentas incluem um modelo hidrológico das bacias hidrográficas e um modelo ecológico da zona costeira adjacente, um sistema de informação geográfica (SIG) e um sistema de apoio à decisão (SAD). O modelo das bacias permite prever os caudais afluentes à Ria Formosa e a qualidade da respectiva água, perante diversos cenários respeitantes à sua gestão, fornecendo assim condições de forçamento para um modelo ecológico desta laguna. O SAD encontra-se em desenvolvimento e destina-se a integrar informação ambiental e sócio-económica. O projecto é participado por técnicos do Parque Natural da Ria Formosa com responsabilidades na gestão deste sistema lagunar, de modo a permitir um entendimento eficaz entre investigadores e decisores.

The role of aquaculture in world food production is increasing very fast, contributing with more ... more The role of aquaculture in world food production is increasing very fast, contributing with more than 40% for the total production of aquatic organisms. The general approach in modern aquaculture resembles much that of industrial agriculture and husbandry, with large energy subsidies and the usage of many chemicals in, predominantly, monoculture systems, with a large ecological footprint. In spite of the large body of regulation available worldwide, there are important ecologic, economic and social impacts in many countries as a result of aquaculture. In some cases, the anticipation of these impacts by local populations represents a negative feedback for aquaculture development. In the present work, a review of those impacts is presented, followed by a discussion of the carrying capacity concept, then by presenting some approaches and methods that may help planning aquaculture developments including the Drives Pressures States Impacts Responses framework, modelling and Decision Support Systems and, finally, by a synthesis of aquaculture related legislation worldwide. The analysis of a large number of works suggests that aquaculture management should be participated by local stakeholders and viewed within the context of other management approaches, such as Integrated Coastal Zone Management. This may allow for a better ecosystemic integration of aquaculture with other activities in line with Ecological Engineering concepts. Likely, there should be more investment in low-trophic level species to reduce aquaculture ecological footprint.

Continental Shelf Research, 2008

This study investigates environmental assessment of artificial reef systems deployed at different... more This study investigates environmental assessment of artificial reef systems deployed at different areas in terms of nutrient cycling and seabed organic enrichment. Two identical artificial reef systems: Olhão Artificial Reef—OAR (37°00′55″N and 007°44′54″W) and Faro Artificial Reef—FAR (36°58′65″N and 008°00′91″W) were deployed in southern Portuguese coast, adjacent to a highly productive coastal lagoon (Ria Formosa) in 1990 and monitorized over

Aquaculture International, 2009

The present work aims to assess the importance of settlement ponds (SP) in semi-intensive fish fa... more The present work aims to assess the importance of settlement ponds (SP) in semi-intensive fish farms by studying benthic dynamics in an aquaculture fish farm, more specifically in the water reservoir (WR) and SP and also in production (P) and nonproduction (C) ponds during a 16-month period. In Portugal, a SP is only mandatory for intensive fish farms, and another objective of the present study is to assess the importance of these areas in semi-intensive fish farms. The WR was the area with highest diversity and evenness, as well as the higher number of exclusive taxa and taxa sensitive to organic enrichment. P and SP samples showed signs of higher disturbance levels, emphasized namely by the association of the opportunistic annelids Capitella spp. and Tubificidae. However, the benthic data from SP points to lower disturbance levels than P both due to an increase in the percentage of sensitive taxa observed in June and October 2004 and by the association of this latter sample with water reservoir samples as evidenced by canonical correspondence analysis. Moreover, a higher and increasing number of taxa when compared with the P area were also observed. Therefore, in semi-intensive fish farms, where effluents from P ponds are directly discharged to the lagoon, the potential environmental impacts would be more severe. In conclusion, the imposition of SP in semi-intensive fish farms should be considered, especially because most fish farms are located within relevant wetland areas.

The ecological assets of an area provide the basic inputs for economic processes. However, econom... more The ecological assets of an area provide the basic inputs for economic processes. However, economic activities directly depending on the environment may affect the ecological (biological, chemical and physical) processes. The Ria Formosa is a multiple-use area, where terrestrial human activities (agriculture, tourism, trading, building construction and industry) may conflict with marine human activities (fishing, aquaculture, salt and sand extraction). The main objective of the present report, developed within the scope of the DITTY Project "Development of an Information Technology Tool for the Management of European Southern Lagoons under the influence of river-basin runoff", was to improve the knowledge on the main socio-economic activities in the Ria Formosa lagoon in order to identify the main stakeholders involved in the ecosystem functioning, and who are the gainers and losers of management options. According to the information gathered in this work, construction, trading and tourism are the most relevant economical activities concerning to revenues, although they may affect the aquatic environment. As primary sector (e.g. fishing, aquaculture) and secondary sector activities (e.g. salt extraction, sand extraction) are highly dependent on the ecosystem's ecological equilibrium, it becomes essential an integrated management of all activities affecting and depending on the environment in order to assure a sustainable development.

Ria Formosa is a natural park managed partly by the Portuguese end-users of the DITTY project -Ri... more Ria Formosa is a natural park managed partly by the Portuguese end-users of the DITTY project -Ria Formosa Natural Park authority, under "Instituto para a Conservação da Natureza (ICN)". There are many conflicting interests over the management of this important coastal area: fishing, tourism, aquaculture, salt production, harbour activities, urban development and conservation. Furthermore, several institutions, such as the Natural Park Authority, municipalities, the Portuguese Navy, just to mention a few, are involved in decision-making over several areas of the natural park. Within DITTY, several scenarios were selected among those relevant for the management of this coastal ecosystem, considering available information from the end-users, relative importance of the mentioned scenarios, modelling and time constraints.

Science of The Total Environment

The current fire regime in the Mediterranean Basin constitutes a serious threat to natural ecosys... more The current fire regime in the Mediterranean Basin constitutes a serious threat to natural ecosystems because it drastically enhances surface runoff and soil erosion in the affected areas. Besides soil particles themselves, soil cations can be lost by fire-enhanced overland flow, increasing the risk of fertility loss of the typically shallow and nutrient poor Mediterranean soils. Although the importance of cations for land-use sustainability is widely recognized, cation losses by post-fire runoff have received little research attention. The present study aimed to address this research gap by assessing total exports of Na(+), K(+), Ca(2+) and Mg(2+) in a recently burnt forest area in north-central Portugal. These exports were compared for two types of planted forest (eucalypt vs. maritime pine plantations), two types of parent materials (schist vs. granite) and for two spatial scales (micro-plot vs. hill slope). The study sites were a eucalypt plantation on granite (BEG), a eucalypt ...

ABSTRACT In Portugal, wildfires occur frequently and affect large areas, on average some 100.000 ... more ABSTRACT In Portugal, wildfires occur frequently and affect large areas, on average some 100.000 ha per year but in extreme years such as 2003 and 2005 over 300.000 ha. Wildfires can lead to considerable changes in geomorphologic and hydrological processes, as evidenced by the strong and sometimes extreme responses in post-fire runoff and erosion reported from various parts of the world, including Portugal. Besides wildfire itself, also post-fire forestry practices can strongly influence the hydrological and erosion response in recently burnt areas. In north-central Portugal, for example, rip ploughing in down-slope direction was found to be far more damaging in terms of soil loss than fire. Whilst rip ploughing in down-slope direction has now by and large been abandoned in the region, the construction of terraces in preparation of new tree and especially eucalypt plantations has become increasingly common. Although terraces are traditionally viewed as a technique for soil conservation, the authors have measured high splash erosion rates on recent terraces and have frequently observed small-scale erosion features and, on one occasion, gully formation over the full hill slope length. Runoff and sediment losses, however, have hardly ever been quantified for recently terraced plantations. In this study, we compared runoff and erosion, at the micro-plot scale, before and after terracing, during the first seven months after a wildfire and during the subsequent 17 months. This was done at two contrasting hill slopes, designated here as eucalypt and pine site. The former was, at the time of the wildfire, covered by eucalypt and then terraced and re-planted with eucalypt over its full extent; the latter was initially covered with pine and then partially terraced and planted with eucalypt and partially left to regenerate spontaneously. Total rainfall was rather similar for the pre- and post-terracing period (1205 and 1437 mm), in spite of their different, above-mentioned durations. The corresponding runoff coefficients were rather similar at the pine site (25-35 %) but markedly higher after than before terracing at the eucalypt site (45 vs. 25 %). Likewise, total sediment losses were much higher after than before terracing at both sites (10-40 vs. 0.1-0.6 Mg ha-1). The spatio-temporal patterns in runoff and erosion during the pre- and post-terracing periods are now being analyzed in more detail.

<p>Wildfires constitute a diffuse source of contamination to aquatic ecosys... more <p>Wildfires constitute a diffuse source of contamination to aquatic ecosystems. In burnt hillslopes, ash and sediments transported by overland flow are a source of potentially hazardous substances, like metals, posing a risk for downstream water bodies. In the present study, post-fire metal mobilization by overland flow was evaluated in 16 m<sup>2 </sup>bounded plots at a eucalypt stand in Albergaria-a-Velha (Aveiro district, North-Central Portugal) that burnt with moderate severity in September 2019. Overland flow samples were collected on a weekly to bi-weekly basis, depending on the occurrence of rain, during the first 6 months after fire. Aside from overland flow samples collected at slope scale, water and sediment samples were also collected in a fire-affected stream within the Albergaria burned catchment, to assess the contamination risk posed by the fire. Samples were collected at three sites along the stream: one upstream, one within and another downstream from the burnt area, after major rainfall events. The metals analysed in this study included, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). Results showed that most metals exhibited a peak in exports immediately after the first significant post-fire rainfall event likely due to the wash-off of the ash layer and high sediment losses, but for some elements like Zn and Cu, exports were more or less constant over time. The fire seems to have had a low impact on the water quality of the affected stream, since metal concentrations were similar between the three study sites. The quality of stream sediments, on the other hand, was clearly affected by the fire, especially after the rainy season. As fire severity and frequency is forecasted to increase in the near future due to climate changes, the results of this work reinforce the importance of water managers to define adaptative strategies to effectively protect freshwater bodies.</p>

<p&amp... more <p>Wildfires constitute a diffuse source of contamination to aquatic ecosystems. In burnt areas, the increase in surface runoff and associated sediment losses after fire, promotes the mobilization of hazardous substances, such as metals and polycyclic aromatic hydrocarbons (PAHs), posing a risk for the adjacent water bodies. In the present study, post-fire metals and PAHs export by surface runoff was evaluated in 16 m<sup>2 </sup>bounded plots in a eucalypt stand in Albergaria-a-Velha (Aveiro district, North-Central Portugal) burnt in September 2019. Runoff samples were collected on a weekly to bi-weekly basis, depending on the occurrence of rainfall, during the first 6 months after fire. The metals analyzed in this study were, vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd) and lead (Pb). As for PAHs, the analyses focused on the 16 compounds classified as priority pollutants by the United States Environmental Protection Agency. Both dissolved and particulate fractions of metals and PAHs in runoff waters were analysed in this work. Preliminary results suggest that metals are more likely to affect the water quality of fire-affected water bodies than PAHs, since low levels of PAHs were found in runoff waters. This work provides valuable information for water managers to minimize the risks of wildfires both to the environment and to public health.</p>

Land Degradation & Development

DITTY (Development of an information technology tool for the management of Southern European lago... more DITTY (Development of an information technology tool for the management of Southern European lagoons under the influence of river-basin runoff) (EESD Project EVK3-CT-2002-00084

Ciência Agronômica, 2007

Resumo-As zonas costeiras representam uma pequena parte da área e do volume dos oceanos. No entan... more Resumo-As zonas costeiras representam uma pequena parte da área e do volume dos oceanos. No entanto, a sua importância como interface entre a terra e o mar é enorme. Mais de 60% da população humana vive a menos de 60 km do mar e, além disso, as zonas costeiras garantem uma série de serviços essenciais à humanidade. Estes ecossistemas funcionam como um mecanismo de convergência de todas as acções levadas a cabo pelo Homem nas bacias hidrográficas adjacentes, sendo por isso necessário, no espírito da Directiva Quadro da Água-DQA-2000/60/EC (UE, 2000), considerá-las na gestão desses sistemas. Apresenta-se, neste trabalho, um conjunto de ferramentas destinadas à gestão integrada de zonas costeiras, desenvolvidas no âmbito de um projecto europeu e utilizando como exemplo o Parque Natural da Ria Formosa (Sul de Portugal). Estas ferramentas incluem um modelo hidrológico das bacias hidrográficas e um modelo ecológico da zona costeira adjacente, um sistema de informação geográfica (SIG) e um sistema de apoio à decisão (SAD). O modelo das bacias permite prever os caudais afluentes à Ria Formosa e a qualidade da respectiva água, perante diversos cenários respeitantes à sua gestão, fornecendo assim condições de forçamento para um modelo ecológico desta laguna. O SAD encontra-se em desenvolvimento e destina-se a integrar informação ambiental e sócio-económica. O projecto é participado por técnicos do Parque Natural da Ria Formosa com responsabilidades na gestão deste sistema lagunar, de modo a permitir um entendimento eficaz entre investigadores e decisores.

The role of aquaculture in world food production is increasing very fast, contributing with more ... more The role of aquaculture in world food production is increasing very fast, contributing with more than 40% for the total production of aquatic organisms. The general approach in modern aquaculture resembles much that of industrial agriculture and husbandry, with large energy subsidies and the usage of many chemicals in, predominantly, monoculture systems, with a large ecological footprint. In spite of the large body of regulation available worldwide, there are important ecologic, economic and social impacts in many countries as a result of aquaculture. In some cases, the anticipation of these impacts by local populations represents a negative feedback for aquaculture development. In the present work, a review of those impacts is presented, followed by a discussion of the carrying capacity concept, then by presenting some approaches and methods that may help planning aquaculture developments including the Drives Pressures States Impacts Responses framework, modelling and Decision Support Systems and, finally, by a synthesis of aquaculture related legislation worldwide. The analysis of a large number of works suggests that aquaculture management should be participated by local stakeholders and viewed within the context of other management approaches, such as Integrated Coastal Zone Management. This may allow for a better ecosystemic integration of aquaculture with other activities in line with Ecological Engineering concepts. Likely, there should be more investment in low-trophic level species to reduce aquaculture ecological footprint.

Continental Shelf Research, 2008

This study investigates environmental assessment of artificial reef systems deployed at different... more This study investigates environmental assessment of artificial reef systems deployed at different areas in terms of nutrient cycling and seabed organic enrichment. Two identical artificial reef systems: Olhão Artificial Reef—OAR (37°00′55″N and 007°44′54″W) and Faro Artificial Reef—FAR (36°58′65″N and 008°00′91″W) were deployed in southern Portuguese coast, adjacent to a highly productive coastal lagoon (Ria Formosa) in 1990 and monitorized over

Aquaculture International, 2009

The present work aims to assess the importance of settlement ponds (SP) in semi-intensive fish fa... more The present work aims to assess the importance of settlement ponds (SP) in semi-intensive fish farms by studying benthic dynamics in an aquaculture fish farm, more specifically in the water reservoir (WR) and SP and also in production (P) and nonproduction (C) ponds during a 16-month period. In Portugal, a SP is only mandatory for intensive fish farms, and another objective of the present study is to assess the importance of these areas in semi-intensive fish farms. The WR was the area with highest diversity and evenness, as well as the higher number of exclusive taxa and taxa sensitive to organic enrichment. P and SP samples showed signs of higher disturbance levels, emphasized namely by the association of the opportunistic annelids Capitella spp. and Tubificidae. However, the benthic data from SP points to lower disturbance levels than P both due to an increase in the percentage of sensitive taxa observed in June and October 2004 and by the association of this latter sample with water reservoir samples as evidenced by canonical correspondence analysis. Moreover, a higher and increasing number of taxa when compared with the P area were also observed. Therefore, in semi-intensive fish farms, where effluents from P ponds are directly discharged to the lagoon, the potential environmental impacts would be more severe. In conclusion, the imposition of SP in semi-intensive fish farms should be considered, especially because most fish farms are located within relevant wetland areas.

The ecological assets of an area provide the basic inputs for economic processes. However, econom... more The ecological assets of an area provide the basic inputs for economic processes. However, economic activities directly depending on the environment may affect the ecological (biological, chemical and physical) processes. The Ria Formosa is a multiple-use area, where terrestrial human activities (agriculture, tourism, trading, building construction and industry) may conflict with marine human activities (fishing, aquaculture, salt and sand extraction). The main objective of the present report, developed within the scope of the DITTY Project "Development of an Information Technology Tool for the Management of European Southern Lagoons under the influence of river-basin runoff", was to improve the knowledge on the main socio-economic activities in the Ria Formosa lagoon in order to identify the main stakeholders involved in the ecosystem functioning, and who are the gainers and losers of management options. According to the information gathered in this work, construction, trading and tourism are the most relevant economical activities concerning to revenues, although they may affect the aquatic environment. As primary sector (e.g. fishing, aquaculture) and secondary sector activities (e.g. salt extraction, sand extraction) are highly dependent on the ecosystem's ecological equilibrium, it becomes essential an integrated management of all activities affecting and depending on the environment in order to assure a sustainable development.

Ria Formosa is a natural park managed partly by the Portuguese end-users of the DITTY project -Ri... more Ria Formosa is a natural park managed partly by the Portuguese end-users of the DITTY project -Ria Formosa Natural Park authority, under "Instituto para a Conservação da Natureza (ICN)". There are many conflicting interests over the management of this important coastal area: fishing, tourism, aquaculture, salt production, harbour activities, urban development and conservation. Furthermore, several institutions, such as the Natural Park Authority, municipalities, the Portuguese Navy, just to mention a few, are involved in decision-making over several areas of the natural park. Within DITTY, several scenarios were selected among those relevant for the management of this coastal ecosystem, considering available information from the end-users, relative importance of the mentioned scenarios, modelling and time constraints.

Science of The Total Environment

The current fire regime in the Mediterranean Basin constitutes a serious threat to natural ecosys... more The current fire regime in the Mediterranean Basin constitutes a serious threat to natural ecosystems because it drastically enhances surface runoff and soil erosion in the affected areas. Besides soil particles themselves, soil cations can be lost by fire-enhanced overland flow, increasing the risk of fertility loss of the typically shallow and nutrient poor Mediterranean soils. Although the importance of cations for land-use sustainability is widely recognized, cation losses by post-fire runoff have received little research attention. The present study aimed to address this research gap by assessing total exports of Na(+), K(+), Ca(2+) and Mg(2+) in a recently burnt forest area in north-central Portugal. These exports were compared for two types of planted forest (eucalypt vs. maritime pine plantations), two types of parent materials (schist vs. granite) and for two spatial scales (micro-plot vs. hill slope). The study sites were a eucalypt plantation on granite (BEG), a eucalypt ...

ABSTRACT In Portugal, wildfires occur frequently and affect large areas, on average some 100.000 ... more ABSTRACT In Portugal, wildfires occur frequently and affect large areas, on average some 100.000 ha per year but in extreme years such as 2003 and 2005 over 300.000 ha. Wildfires can lead to considerable changes in geomorphologic and hydrological processes, as evidenced by the strong and sometimes extreme responses in post-fire runoff and erosion reported from various parts of the world, including Portugal. Besides wildfire itself, also post-fire forestry practices can strongly influence the hydrological and erosion response in recently burnt areas. In north-central Portugal, for example, rip ploughing in down-slope direction was found to be far more damaging in terms of soil loss than fire. Whilst rip ploughing in down-slope direction has now by and large been abandoned in the region, the construction of terraces in preparation of new tree and especially eucalypt plantations has become increasingly common. Although terraces are traditionally viewed as a technique for soil conservation, the authors have measured high splash erosion rates on recent terraces and have frequently observed small-scale erosion features and, on one occasion, gully formation over the full hill slope length. Runoff and sediment losses, however, have hardly ever been quantified for recently terraced plantations. In this study, we compared runoff and erosion, at the micro-plot scale, before and after terracing, during the first seven months after a wildfire and during the subsequent 17 months. This was done at two contrasting hill slopes, designated here as eucalypt and pine site. The former was, at the time of the wildfire, covered by eucalypt and then terraced and re-planted with eucalypt over its full extent; the latter was initially covered with pine and then partially terraced and planted with eucalypt and partially left to regenerate spontaneously. Total rainfall was rather similar for the pre- and post-terracing period (1205 and 1437 mm), in spite of their different, above-mentioned durations. The corresponding runoff coefficients were rather similar at the pine site (25-35 %) but markedly higher after than before terracing at the eucalypt site (45 vs. 25 %). Likewise, total sediment losses were much higher after than before terracing at both sites (10-40 vs. 0.1-0.6 Mg ha-1). The spatio-temporal patterns in runoff and erosion during the pre- and post-terracing periods are now being analyzed in more detail.