Earth's biosphere is undergoing drastic reorganization due to the sixth mass extinction brought on by the Anthropocene. Impacts of local and regional extirpation of species have been demonstrated to propagate through the complex interaction networks they are part of, leading to secondary extinctions and exacerbating biodiversity loss. Contemporary ecological theory has developed several measures to analyse the structure and robustness of ecological networks under biodiversity loss. However, a toolbox for directly simulating and quantifying extinction cascades and creating novel interactions (i.e. rewiring) remains absent. Here, we present NetworkExtinction—a novel R package which we have developed to explore the propagation of species extinction sequences through ecological networks and quantify the effects of rewiring potential in response to primary species extinctions. With NetworkExtinction, we integrate ecological theory and computational simulations to develop functionality with which users may analyse and visualize the structure and robustness of ecological networks. The core functions introduced with NetworkExtinction focus on simulations of sequential primary extinctions and associated secondary extinctions, allowing user‐specified secondary extinction thresholds and realization of rewiring potential. With the package NetworkExtinction, users can estimate the robustness of ecological networks after performing species extinction routines based on several algorithms. Moreover, users can compare the number of simulated secondary extinctions against a null model of random extinctions. In‐built visualizations enable graphing topological indices calculated by the deletion sequence functions after each simulation step. Finally, the user can estimate the network's degree distribution by fitting different common distributions. Here, we illustrate the use of the package and its outputs by analysing a Chilean coastal marine food web. NetworkExtinction is a compact and easy‐to‐use R package with which users can quantify changes in ecological network structure in response to different patterns of species loss, thresholds and rewiring potential. Therefore, this package is particularly useful for evaluating ecosystem responses to anthropogenic and environmental perturbations that produce nonrandom and sometimes targeted, species extinctions.

<![CDATA[En los últimos 50 años, el rol trófico de los consumidores se convirtió en un tópico importante en la ecología de costas rocosas de Chile, centrándose en especies de equinodermos, crustáceos y moluscos tipificadas como herbívoros y carnívoros principales del sistema intermareal. Sin embargo, la dieta y comportamiento de muchos consumidores aún no son bien conocidos, dificultando abordar problemas clave relativos por ejemplo a la importancia de la omnivoría, competencia intra-e inter-específica o especialización individual. Intentando corregir algunas deficiencias, ofrecemos a los investigadores un registro dietario exhaustivo y descriptores ecológicos relevantes para 30 especies de amplia distribución en el Pacífico sudeste, integrando muestreos estacionales entre 2004 y 2007 en 4 localidades distribuidas en 1.000 km de costa en el norte de Chile. Basados en el trabajo de terreno y laboratorio, se presenta : (a) una matriz de consumidores-recursos generada por análisis de alta resolución del contenido intestinal de 6.377 individuos, incluyendo 222 presas (80% identificadas a nivel de especie o género), (b) estimaciones de densidad, tamaño corporal (longitud y peso), amplitud dietaria (a nivel de individuo y especie), y diversidad intra-individual de los consumidores, (c) una ordenación nMDS de la similitud en composición dietaria entre consumidores, e información para cada consumidor sobre importancia relativa y frecuencia de ocurrencia de las presas más comunes. Considerando la amplia dieta omnívora y alta superposición de los consumidores, discutimos su potencial competitivo y el rol de la especialización individual en su carácter generalista, destacando la necesidad de reevaluar su comportamiento y efectos ecológicos en la comunidad intermareal.]]>

Species diversity underpins all ecosystem services that support life. Despite this recognition and the great advances in detecting biodiversity, exactly how many and which species co-occur and interact, directly or indirectly in any ecosystem is unknown. Biodiversity accounts are incomplete; taxonomically, size, habitat, mobility or rarity biased. In the ocean, the provisioning of fish, invertebrates and algae is a fundamental ecosystem service. This extracted biomass depends on a myriad of microscopic and macroscopic organisms that make up the fabric of nature and which are affected by management actions. Monitoring them all and attributing changes to management policies is daunting. Here we propose that dynamic quantitative models of species interactions can be used to link management policy and compliance with complex ecological networks. This allows managers to qualitatively identify ‘interaction-indicator’ species, which are highly impacted by management policies through propagation of complex ecological interactions. We ground the approach in intertidal kelp harvesting in Chile and fishers' compliance with policies. Results allow us to identify sets of species that respond to management policy and/or compliance, but which are often not included in standardized monitoring. The proposed approach aids in the design of biodiversity programmes that attempt to connect management with biodiversity change. This article is part of the theme issue ‘Detecting and attributing the causes of biodiversity change: needs, gaps and solutions’.

The European rabbit (Oryctolagus cuniculus) is one of the main invasive species in Chile, where it became naturalized ca. 150 years ago. Their high reproductive capacity, lack of specialist predators, and great adaptability favored the settlement of rabbits in diverse mainland and island ecosystems of the country. Recently, rabbits have become central players in semi-arid ecosystems, such as those represented in Las Chinchillas National Reserve in north-central Chile. We undertook to analyze the place and role of rabbits in the food web of that Reserve, based on a bibliographic review and long-term annual data gathered from 1987 until 2022 (36 years). Results showed that the network comprised 77 species, where 69% were primary producers (plants), 18% were mid-level consumers (herbivores), and 13% were top-level consumers (predators). The most connected species in the food web was the rabbit, which positively or negatively affected the species interacting with it. Predators such as Galictis cuja, Geranoaetus polyosoma, Leopardus colocolo, and Puma concolor, and the scavenger Vultur gryphus, could be negatively affected by an eventual decrease (natural or human-caused) in the rabbit population of the Reserve. To the contrary, primary producers such as Oxalis perdicaria, Plantago hispidula, Schizanthus parvulus, Senna cumminggi, and Tropaeolum azureum could be positively affected by an increase in their biomass in response to a decrease in rabbits, favoring native rodents. We consider that analyzing the rabbit-centered food web and its impacts on native interacting species allows a better understanding of the relevance of invasive species in the local community, providing conceptual tools for rabbit management.

Rising global seafood demand poses increasing challenges for sustainable fishery management. This is particularly the case in the Global South, where many small-scale fisheries are likely to expand as they gain access to larger markets. Using Chile as a case study, we assess brachyuran crab fisheries and provide a forward-looking view on the sustainability challenges of possible increases in demand by bringing together data on supply, demand, management, and, literature review. Dominated by two species (Metacarcinus edwarsii and Cancer porteri), production has centered in southern Chile and has fluctuated over the past decade, with landings declining since 2018. Between 20% and 30% of crab caught is exported, mostly to the United States and Belgium. In Belgium Chile is the third largest supplier. Few management regulations and monitoring programs exist. Limited spatio-temporal stock assessments, suggests the status of the dominant crab species may be jeopardized. Apart from ecology, the state of knowledge is limited across socio-economic, market, and fisheries management dimensions. There are initiatives to improve with an established Fisheries Improvement Project (FIP) in southern Chile. However, the lack of evidence of policy and management improvements has inactivated the FIP until the developed management plan proposal, based on an adaptive and precautionary approach (considering biological, ecological, economic, and social objectives) be approved by the government. This work reveals the importance of understanding the dynamics between supply and demand from holistic perspectives as well as the role of local efforts for resource sustainability in the context of increasing national and global crab demand.