DCDavid Cevallos

David Cevallos

*This is an algorithmically generated author record based on publicly available information.

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years


David Cevallos has a total of 17 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Assessing Water-Saving Technologies and the Impact of Giant Tortoise Herbivory on the Restoration of Opuntia megasperma var. orientalis on Española Island—Galapagos

    by David Cevallos, Patricia Jaramillo Díaz

    The prickly pear (Opuntia megasperma var. orientalis), a pivotal species for the ecological balance of Española Island in Galapagos, has witnessed a severe decline in its population due to the enduring presence of introduced feral goats over several decades. Additionally, the inherent slow recovery of this species, requiring several years of development, has contributed to its population decline. Several attempts were carried out to restore this species, but they were not successful due to the island’s extreme arid conditions. Subsequently, innovative water-saving technologies were introduced to ensure the survival and growth of the Opuntia species. Two water-saving technologies, Groasis Waterboxx® and Hydrogel, were applied in two distinct treatments, the first involving Waterboxx solely, and the second combining Waterboxx with Hydrogel, alongside a control group. Planting involved two types of cacti: cladodes and seedlings. To safeguard against potential damage from giant tortoises and local birds, protective mesh fencing was installed around the plants. Each monitoring session recorded plant survival and growth, evaluating the impact of water-saving technologies on cactus survival, maximum plant height reached, age at the time of plant death, and growth achieved since planting. Additionally, the study assessed the influence of climate on plant survival and growth. Unfortunately, the employment of protective mesh fences and Waterboxx containers resulted in the unintended loss of specific bird species. Consequently, a decision was taken to remove these protective measures, resulting in a substantial rise in herbivorous activity, and the subsequent mortality of nearly all plants. Our findings underscore the efficacy of water-saving technologies in Opuntia restoration. However, successful application necessitates a better understanding of these technologies within the unique conditions of the island. Future endeavors should focus on refining these techniques to minimize avian mortality while fostering biodiversity and restoring ecological equilibrium.


  • Open Access

    Water-Saving Technologies in Galapagos Agriculture: A Step towards Sustainability

    by Patricia Jaramillo Díaz, Anna Calle-Loor, Nicolás Velasco, David Cevallos

    Water scarcity and salinity pose significant challenges for agriculture in the Galapagos Islands, severely limiting crop yields needed to sustainably meet the growing demands of the human population in the archipelago. To address this issue, environmentally friendly water-saving technologies such as Hydrogel and Groasis Growboxx were considered to be potential solutions. This study focused on evaluating the effectiveness of Hydrogel application on five crops: Broccoli (Brassica oleracea), Cucumber (Cucumis melo), Pepper (Capsicum annuum), Tomato (Solanum lycopersicum), and Watermelon (Citrullus lanatus), from 2017 to 2018. The experiment stopped due to the pandemic in 2019–2020. When the study continued in 2021, Growboxx® was introduced as a treatment for Pepper and Tomato. This study revealed that the application of Hydrogel resulted in enhanced yields, with the degree of improvement varying across different crops and cultivation periods. Notably, when comparing Hydrogel and Growboxx treatments, differences of up to 30% in fruit weight were observed. However, it is important to note that these results can vary in different environments. For example, in Tomato cultivation, Growboxx exhibited 10% higher fruit weight in San Cristobal compared to Santa Cruz Island. Our findings provide valuable insights for stakeholders in the Galapagos Islands, offering crop-specific guidance to support informed decisions on adopting the most appropriate technologies for their farms.


  • Open Access

    Adoption of Sustainable Agriculture Practices through Participatory Research: A Case Study on Galapagos Islands Farmers Using Water-Saving Technologies

    by Patricia Jaramillo Díaz, Anna Calle-Loor, Ekaterina Gualoto, Carlos Bolaños, David Cevallos

    Agriculture in the populated islands of the Galapagos Archipelago, a protected area due to its unique biodiversity, has been detrimental to its conservation but highly required to meet food necessities. A potential solution to make agricultural farming more sustainable is adopting water-saving technologies (WSTs). Therefore, this study aimed to test the effectiveness of using WSTs such as Groasis Waterboxx® in three of the most valuable crops in the islands through participatory research with the involvement of a group of farmers from the Floreana and Santa Cruz islands and explore a possible transition to more sustainable agricultural practices. Capsicum annuum, Cucumis sativus and Solanum lycopersicum were cultivated using Groasis Waterboxx® and compared to conventional irrigation practices (drip-irrigated controls) to assess the variability of productivity, the number of fruits and individual fruit weight (IFW). In addition, differences in plant traits were analyzed by crop, and island. Results suggested that WSTs such as Groasis Waterboxx® may provide on-farm benefits regarding the yields of the studied traits. From this study, it is difficult to determine whether participation in such a research study will permanently change irrigation practices. However, the participant’s responses to the study suggest an increase in their understanding of the use and benefits of WST.


  • DOES SEED TRAIT VARIABILITY SUPPORT PRELIMINARY SEED TRANSFER ZONES FOR HUNGARY?

    by D. Cevallos, K. Szitar, M. Halassy, A. Kövendi-Jakó, K. Török


  • Származási régiók növényföldrajzi felülvizsgálata honos fajok magjainak restaurációs célú felhasználására

    by Katalin Török, David Cevallos, Ákos Bede-Fazekas

    A biodiverzitás pusztulása miatt az ökológiai restauráció a legmagasabb szintű politikai döntéshozás homlokterébe került. A restauráció területének növelése érdekében a honos fajok magjainak nagyobb mértékű felhasználására van szükség. A lokálisan adaptálódott populációból származó magok használatát rendelet szabályozza, melyet hazánkban a közigazgatási régiók határaihoz igazítottak. Jelen dolgozatban magtranszferzónák kijelölésére teszünk kísérletet flóra-, vegetáció- és tájszintű régiós térképek, valamint többrétegű potenciálisvegetáció-modell felhasználásával. Új módszert fejlesztettünk a zónalehatárolás megbízhatóságának elemzésére. A 4–9 egységből álló magtranszferzóna-rendszerek megbízhatósági elemzésének eredménye alapján a négy vagy a hét zónából álló rendszer tűnik alkalmasabbnak. További finomhangolás és tesztelések után a jelenleg érvényben lévő rendelet módosítandó.


  • Open Access

    Seed transfer zones based on environmental variables better reflect variability in vegetation than administrative units: evidence from Hungary

    by David Cevallos, Ákos Bede‐Fazekas, Eszter Tanács, Katalin Szitár, Melinda Halassy, Anna Kövendi‐Jakó, Katalin Török

    To preserve the natural genetic pattern of species and to avoid the introduction of nonadapted ecotypes during restoration, seed transfer should be spatially restricted. Instead of applying administrative borders in the absence of species‐specific empirical data, biogeographical knowledge can be used as a proxy. Hungary was used as a suitable test region for this approach. The aims of the study were (1) to produce an evidence‐based seed transfer zone (STZ) map applying the Multiple Potential Natural Vegetation model; (2) to assess the uncertainty of the resulting STZ map; and (3) to compare the present seed transfer regulation based on administrative regions with the evidence‐based STZ map. The analysis was based on a floristic map, a vegetation map, and a landscape map of Hungary. Intersected polygons of the three maps were filled with Multiple Potential Natural Vegetation data and clustered to produce seven contiguous units that can serve as STZs. The uncertainty analyses provided a numerical comparison between the two approaches and demonstrated the inadequacy of defining administrative regions as STZs. The practical result of the study is the production of an evidence‐based STZ map that could replace the administrative map currently used for regulation in Hungary. Moreover, this map helps to develop native seed propagation and to enhance ecological restoration. We conclude that field‐based potential vegetation models, similar to the Multiple Potential Natural Vegetation, are suitable for STZ development in countries lacking an evidence‐based system for seed transfer.