Unsubstantiated Claims Can Lead to Tragic Conservation Outcomes

Hernández, Jaqueline García; Bracho, L. Rojas; Brusca, Richard C.; Borrego, Saúl Álvarez; Brownell, Robert L.; Camacho-Ibar, Víctor F.; Gonzalez, Gerardo Jorge Ceballos; Cueva, Horacio de la; Hastings, Philip A.; Cárdenas-Hinojosa, Gustavo; Jaramillo-Legorreta, Armando; Legorreta, Rodrigo Medellín; Mesnick, Sarah L.; Garcia, Edwyna Nieto; Ramírez, Jorge Jiménez; Gonzalez, Maria Enriqueta Velarde; Vidal, Omar; Findley, Lloyd T.; Taylor, Barbara L.

doi:10.1093/biosci/biy138

Cited by 10 publications

(3 citation statements)

References 20 publications

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“…As these populations continue rebuilding, additional energy sources in the form of marine-derived nutrients will further shape food web response to dam removal. Continuing to examine how this energy moves throughout the food web will help us better predict outcomes of future dam removal and river restoration projects [79].…”

Section: Ecosystem Resilience and Recoverymentioning

confidence: 99%

Shifting food web structure during dam removal—Disturbance and recovery during a major restoration action

et al. 2020

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We measured food availability and diet composition of juvenile salmonids over multiple years and seasons before and during the world's largest dam removal on the Elwha River, Washington State. We conducted these measurements over three sediment-impacted sections (the estuary and two sections of the river downstream of each dam) and compared these to data collected from mainstem tributaries not directly affected by the massive amount of sediment released from the reservoirs. We found that sediment impacts from dam removal significantly reduced invertebrate prey availability, but juvenile salmon adjusted their foraging so that the amount of energy in diets was similar before and during dam removal. This general pattern was seen in both river and estuary habitats, although the mechanisms driving the change and the response differed between habitats. In the estuary, the dietary shifts were related to changes in invertebrate assemblages following a hydrological transition from brackish to freshwater caused by sediment deposition at the river's mouth. The loss of brackish invertebrate species caused fish to increase piscivory and rely on new prey sources such as plankton. In the river, energy provided to fish by Ephemeroptera, Plecoptera, and Trichoptera taxa before dam removal was replaced first by terrestrial invertebrates, and then by sediment-tolerant taxa such as Chironomidae. The results of our study are consistent with many others that have shown sharp declines in invertebrate density during dam removal. Our study further shows how those changes can move through the food web and affect fish diet composition, selectivity, and energy availability. As we move further along the dam removal response trajectory, we hypothesize that food web complexity will continue to increase as annual sediment load now approaches natural background levels, anadromous fish have recolonized the majority of the watershed between and above the former dams, and revegetation and microhabitats continue to develop in the estuary.

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Section: Ecosystem Resilience and Recoverymentioning

confidence: 99%

Shifting food web structure during dam removal—Disturbance and recovery during a major restoration action

et al. 2020

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“…With only two speakers alive in late 2018, the Kiliwa is Mexico's most endangered language and is condemned to extinction (INALI, 2012;Caccavari Garza, 2014). And, with a population of fewer than two dozen individuals in 2018 (Comité International para la Recuperación de la Vaquita [CIRVA], 2019), probably even fewer today, the vaquita porpoise (Phocoena sinus), Mexico's only endemic and the world's most endangered marine mammal, is being driven to extinction by illegal fishing for the endangered and endemic totoaba (Totoaba macdonaldi) (Vidal, 1995;Brusca, Álvarez-Borrego, Hastings, & Findley, 2017;Thomas et al, 2017;Rojas-Bracho et al, 2018).…”

Section: Languagesmentioning

confidence: 99%

Mexico’s Biocultural Diversity in Peril

Vidal

Brusca

2020

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Introduction: Places with high species diversity have high linguistic diversity, whereas areas with low species diversity tend to have low linguistic diversity. Objective: To characterize the intriguing relationship between biological and cultural diversity, a correlation that has been discussed at a global scale, but here tested for the first time in Mexico. Methods: We compiled exhaustive databases on both endangered species and endangered languages, and reviewed available literature on Mexico’s biocultural diversity with a focus on endangered and critically endangered species and languages. Results: With 364 living languages, Mexico is the world’s fifth most linguistically diverse country, but 64 of these languages are facing a very high risk of disappearance and 13 have already disappeared. Mexico is also the fourth most biologically diverse country, but 1 213 species of its flora and fauna are threatened with extinction and at least 127 species were recently extinct. Conclusions: Indigenous peoples are custodians of much of the world’s biocultural diversity. As the world grows less linguistically and culturally diverse, it is also becoming less biologically diverse. Mexico’s biological and linguistic diversity show strong geographic overlap, with the states of Oaxaca, Chiapas, Veracruz, Guerrero, and Michoacán harboring most species and most languages. Similarly, Mexico’s biodiversity hotspots mirror language hotspots, and areas with the highest number of endangered species overlap with areas where the endangerment of languages is also the highest.

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“…However, existing in situ management potentially risks further declines if other factors are primarily responsible for regulating porpoise population dynamics (cf. Rojas-Bracho et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Precautionary Principle or Evidence-Based Conservation? Assessing the Information Content of Threat Data for the Yangtze Finless Porpoise

et al. 2022

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Conservation management requires evidence, but robust data on key parameters such as threats are often unavailable. Conservation-relevant insights might be available within datasets collected for other reasons, making it important to determine the information content of available data for threatened species and identify remaining data-gaps before investing time and resources in novel data collection. The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) has declined severely across the middle-lower Yangtze, but multiple threats exist in this system and the relative impact of different anthropogenic activities is unclear, preventing identification of appropriate mitigation strategies. Several datasets containing information on porpoises or potential threats are available from past boat-based and fishing community surveys, which might provide novel insights into causes of porpoise mortality and decline. We employed multiple analytical approaches to investigate spatial relationships between live and dead porpoises and different threats, reproductive trends over time, and sustainable offtake levels, to assess whether evidence-based conservation is feasible under current data availability. Our combined analyses provide new evidence that mortality is spatially associated with increased cargo traffic; observed mortality levels (probably a substantial underestimate of true levels) are unsustainable; and population recruitment is decreasing, although multiple factors could be responsible (pollutants, declining fish stocks, anthropogenic noise, reduced genetic diversity). Available data show little correlation between patterns of mortality and fishing activity even when analyzed across multiple spatial scales; however, interview data can be affected by multiple biases that potentially complicate attempts to reconstruct levels of bycatch, and new data are required to understand dynamics and sustainability of porpoise-fisheries interactions. This critical assessment of existing data thus suggests that in situ porpoise conservation management must target multiple co-occurring threats. Even limited available datasets can provide new insights for understanding declines, and we demonstrate the importance of an integrative approach for investigating complex conservation problems and maximizing evidence in conservation planning for poorly known taxa.

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Unsubstantiated Claims Can Lead to Tragic Conservation Outcomes

Cited by 10 publications

References 20 publications

Shifting food web structure during dam removal—Disturbance and recovery during a major restoration action

Shifting food web structure during dam removal—Disturbance and recovery during a major restoration action

Mexico’s Biocultural Diversity in Peril

Precautionary Principle or Evidence-Based Conservation? Assessing the Information Content of Threat Data for the Yangtze Finless Porpoise

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