Population Viability Analysis in Endangered Species Recovery Plans: Past Use and Future Improvements

Abstract

Using the results of a survey of recovery plans for threatened and endangered species, we evaluated the role that Population Viability Analysis (PVA) has played in recovery planning and management of rare species in the United States. Although there was a significant increase over time in the percentage of plans presenting information on PVA and assigning recovery tasks to collect more such information, the use of PVA was still called for in less than half of the plans approved since 1991. Because scarcity of data for rare species may be limiting the application of PVA to endangered species, we also assessed how often recovery plans proposed to collect the full complement of data required to perform four general types of PVA. For most of the species in the database, proposed monitoring data would allow the simplest type of PVA method (i.e., analysis of total population counts) to be applied, but more complex PVAs would be possible for Ͻ25% of the species. We conclude with brief recommendations for how the use of PVA in endangered species recovery planning might be improved in the future.

Viabilidad poblacional de <i>Alouatta palliata</i> (Primates: Atelidae) y <i>Cebus capucinus</i> (Primates: Cebidae) en el Refugio de Vida Silvestre Privado Nogal, Sarapiquí, Heredia, Costa Rica

“…Estas limitaciones se pueden superar a medida que nuevas investigaciones sobre las especies revelen nueva información que se pueda utilizar para mejorar y actualizar los modelos de los PVA (Lidenmayer et al 1993). Varios autores sostienen que la fortaleza de los PVA radica en utilizarlos como una herramienta en programas de investigación de dinámica poblacional y en la ayuda de toma de decisiones en el establecimiento e implementación de estrategias relacionadas con el mantenimiento y manejo de poblaciones pequeñas (Boyce 1992, Lidenmayer et al 1993, Bessinger & Westphal 1998, Harwood 2000, Morris et al 2002Peterson et al 2003, Drechsler 2004.…”

Assessing population viability while accounting for demographic and environmental uncertainty

“…For rare species of conservation concern, there are often insufficient data to estimate all the demographic parameters required to understand the population-level effects of environmental variation (Morris et al 2002, Manuscript received 22 April 2013; revised 3 December 2013; accepted 10 January 2014. Corresponding Editor: E. E. Crone. 4 E-mail: steffen.oppel@rspb.org.uk Reed et al 2002).…”

“…Environmental perturbations or long-term climatic changes can affect several demographic parameters, and integrating these complex interactions to assess the viability of a population can be challenging (Katzner et al 2006, Nadeem andLele 2012). Matrix population models, the standard tool for the study of population dynamics (Morris et al 2002), may not offer reliable population projections if environmental conditions in the future deviate from the conditions during which data were collected , or if unobservable demographic processes such as transience and immigration affect population dynamics (Ellis and Crone 2013). Incorporating the environmental drivers of demographic parameters and demographic processes such as immigration into population projections may therefore improve forecasts and strengthen the practical relevance of population viability assessments.…”

Measure Twice, Estimate Once: Pacific Salmon Population Viability Analysis for Highly Variable Populations

“…Several PVA methods have been used for modeling listed salmon populations, beginning with spawner-recruit (SR) models familiar to many fisheries biologists (e.g., Marmorek et al 1998;Paulsen and Hinrichsen 2002). More recently, researchers, drawing on methods used for other ESAlisted vertebrate species (e.g., northern spotted owl Strix occidentalis caurina, loggerhead sea turtle Caretta caretta, snail kite Rostrhamus sociabilis, and Bachman's sparrow Aimophifa aestivulis; Morris et al 2002), have employed diffusion approximation methods (e.g., Holmes 2004;Holmes and Semmens 2004). These methods have also been applied for long-term projections by management agencies at the evolutionarily significant unit (ESU) and population levels (NOAA 2000).…”