Programas de seguimiento para evaluar los esfuerzos de reintroducción: un componente crítico en la recuperación

Reintroduction is a powerful tool in our conservation toolbox. However, the necessary follow-up, i.e. long-term monitoring, is not commonplace and if instituted may lack rigor. We contend that valid monitoring is possible, even with sparse data. We present a means to monitor based on demographic data and a projection model using the Wyoming toad (Bufo baxteri) as an example. Using an iterative process, existing data is built upon gradually such that demographic estimates and subsequent inferences increase in reliability. Reintroduction and defensible monitoring may become increasingly relevant as the outlook for amphibians, especially in tropical regions, continues to deteriorate and emergency collection, captive breeding, and reintroduction become necessary. Rigorous use of appropriate modeling and an adaptive approach can validate the use of reintroduction and substantially increase its value to recovery programs. Key words: Reintroduction, Monitoring, Adaptive processes, Amphibians, Bufo baxteri.La reintroducción es un utensilio muy potente en nuestra caja de herramientas conservacionista. No obstante, el seguimiento necesario, es decir, el seguimiento a largo plazo, no es un hecho común, y si se da, puede ser poco rigurosa. Sostenemos que el seguimiento válido es posible, incluso cuando los datos son escasos o están dispersos. Presentamos aquí un medio de seguimiento basado en datos demográficos y un modelo de proyección utilizando al sapo de Wyoming (Bufo baxteri) como ejemplo. Usando un proceso repetitivo, se trabajan gradualmente los datos existentes de tal forma que aumente la fiabilidad de las estimas demográficas y sus subsecuentes deducciones. La reintroducción y el seguimiento defendible pueden hacerse cada vez más importantes, dada la problemática de los anfibios, especialmente en las regiones tropicales, donde continua deteriorándose, y se hacen necesarias la captura y la cría en cautividad para la reintroducción posterior. Un uso riguroso de la construcción de modelos apropiada y un punto de vista adaptativo pueden hacer válido el uso de la reintroducción y aumentar sustancialmente su valor en los programas de recuperación. Palabras clave: Reintroducción, Seguimiento, Procesos adaptativos, Anfibios, Bufo baxteri

Mortality of Parental Mountain Plovers (\u3ci\u3eCharadrius montanus\u3c/i\u3e) during the Post-hatching Stage

Monitoring, management, and conservation of grassland birds are topics of importance because of widespread population declines. Annual estimates of survival are available for many species, however knowledge of how survival varies on a seasonal basis remains poor. Information on the relative effects of breeding, overwintering, and migratory periods on population dynamics is necessary for effective management. Mortality risks often vary with the stage of the breeding cycle. In precocial species, mortality risks of adult birds are often higher during post-hatching care than prehatching. Using a multistate modeling approach, I investigated the influence of both environmental characteristics, measured by habitat, and individual characteristics, measured by sex and body mass, on post-hatching parental mortality of a declining grassland species, the Mountain Plover (Charadrius montanus). I found minimal evidence to support the effect of habitat, sex, or body mass on post-hatching parental mortality. Daily parental mortality was 0.0037 (SE = 0.0007, CI = 0.0026, 0.0053) and survival during the 30-day post-hatching period was 0.8943 (SE = 0.0187, CI = 0.8512, 0.9255). The findings from this study provide an understanding of the associations with today’s grassland habitats and the dynamics of Mountain Plovers during the breeding season. Prior to assessing if alterations in habitats are acting more on post-hatching than the other stages of the annual cycle for the Mountain Plover, information on survival during other breeding stages and during migration is needed to assist in developing effective conservation and management plans

Monitoring programs to assess reintroduction efforts: a critical component in recovery

Reintroduction is a powerful tool in our conservation toolbox. However, the necessary follow–up, i.e. long–term monitoring, is not commonplace and if instituted may lack rigor. We contend that valid monitoring is possible, even with sparse data. We present a means to monitor based on demographic data and a projection model using the Wyoming toad (Bufo baxteri) as an example. Using an iterative process, existing data is built upon gradually such that demographic estimates and subsequent inferences increase in reliability. Reintroduction and defensible monitoring may become increasingly relevant as the outlook for amphibians, especially in tropical regions, continues to deteriorate and emergency collection, captive breeding, and reintroduction become necessary. Rigorous use of appropriate modeling and an adaptive approach can validate the use of reintroduction and substantially increase its value to recovery programs

The Effects of Beetle-Induced Tree Death on Forest Bird Diversity in Western Montana

In forest ecosystems, climate change can hinder management success by increasing the frequency and intensity of fire and insect outbreaks that cause massive tree die-offs and abrupt habitat change. Resource managers often use ecological indicators to gain insight into the health and status of ecosystems due to the challenge of monitoring all aspects of any ecosystem. Birds are increasingly identified as appropriate taxa for predicting changes in biodiversity and ecological integrity around the globe. We assessed the effects of bark beetle induced forest die-off on patterns of avian diversity in western Montana. We used songbirds, which are ubiquitous and possess attributes capturing the complexity of forests as ecological indicators. In addition to assessing the effects of bark beetle forest die-off on bird diversity we also sought to examine the relative importance of the “conspecific neighborhood” in influencing species-level occurrence rates at a given survey location. This approach is motivated by the idea that individuals of a species aggregate around resources. It follows, that a species is more likely to occur in a patch surrounded by other occupied patches (the conspecific neighborhood). Incorporating measures of spatial autocorrelation in ecological studies is not new. However, this topic is only just beginning to be applied in the context of more recent analytical advances such as Bayesian multi-species hierarchal models used to estimate species abundance and occurrence rates

Possible Use of Wading Birds as Beaters by Snail Kites, Boat-Tailed Grackles, and Limpkins

Foraging in single- or mixed-species flocks is common among many bird species, and the advantages of being in these flocks have been the focus of several investigations (reviewed by Moynihan 1962, Bertram 1978). It has been hypothesized that birds occurring in mixed-species flocks gain advantages from (1) reduced predation risk (e.g., Moynihan 1962, Morse 1970), (2) increased foraging efficiency (e.g., Moynihan 1962, Morse 1970), or (3) social learning (e.g., Ward and Zahavi 1973). Here, we report the anomalous occurrence of flocks consisting of species not typically found in the types of aggregations we describe and suggest the possible function of these aggregations with respect to these hypotheses