Monitoring of terrestrial avifauna in six habitats on St. Eustatius, Caribbean Netherlands, 2009–2017

Madden, Hannah; Zanten, Ambrosius van

doi:10.18475/cjos.v50i1.a4

Cited by 6 publications

(7 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We also detected Caribbean Martin (Progne dominicensis)-a regional breeding endemic that is present on Grenada in May-but as with previous observations (Wunderle 1985, see also eBird records), this species was not abundant. We detected relatively few Green-throated Carib across the island, with this species being less abundant than the Antillean Crested Hummingbird, as also noted on other islands (Madden and van Zanten 2020). However, our observations suggest that this species is locally abundant and tended to occur at higher elevations.…”

Section: Fig 2 Pearson Residuals Of Expectedsupporting

confidence: 63%

“…Our density estimates for Bananaquits across different habitats are consistent with previous estimates for Grenada; reported as 2 (thorn-scrub) to 12 (coconut plantations) individuals per ha (Wunderle 1984), though our survey did not include all habitat types documented in this earlier study. Bananaquits are one of the most abundant species throughout the Caribbean (Paice and Speirs 2010, Wolff et al 2018, Madden and van Zanten 2020. The Gray Kingbird, another common species across the region, is more abundant in open habitats at lower elevations (Smith and Jackson 2020).…”

Section: Fig 2 Pearson Residuals Of Expectedmentioning

confidence: 99%

See 1 more Smart Citation

Abundance and density estimates of landbirds on Grenada

Devenish‐Nelson

Nelson

2021

JCO

View full text Add to dashboard Cite

Abstract Throughout the Caribbean, resident landbirds have been subject to proportionately limited research compared to migrant species. In Grenada in particular, there is uncertainty about the status of several regional endemics, including the Grenada Flycatcher (Myiarchus nugator) and the Lesser Antillean Tanager (Stilpnia cucullata). We conducted distance sampling point counts (n = 199) in forested and agricultural habitats across Grenada in 2018 and 2019 to estimate the distribution and relative abundance of resident bird species (n = 1,235 detections). For species with more than 30 observations, we estimated species density using hierarchical distance models, including site-specific habitat covariates of land cover and elevation. We detected over 90% (n = 32) of the previously recorded landbird species during our surveys. Species turnover was low compared to a similar survey conducted in the 1980s, with a difference of four species between the two studies. These differences could be attributed to recent introductions, seasonality, sampling intensity, or other methodological differences between these studies. We had sufficient observations to estimate density for nine resident species, including the endemic Antillean Crested Hummingbird (Orthorhyncus cristatus; 1.68 ind./ha), Lesser Antillean Tanager (1.02 ind./ha), Lesser Antillean Bullfinch (Loxigilla noctis; 0.73 ind./ha), and Grenada Flycatcher (0.59 ind./ha). Our results provide an important baseline for future monitoring and conservation work, including monitoring the impacts of climate change, provision of ecosystem services, or land use change. Keywords avian conservation, Caribbean, distance sampling, endemic, habitat use, hierarchical population model, population density, species turnover Resumen Estimaciones de abundancia y densidad de aves terrestres en Granada • En todo el Caribe, las aves terrestres residentes han sido objeto de investigaciones relativamente más limitadas que las especies migratorias. En Granada, en particular, existen dudas sobre el estado de varias especies endémicas regionales, como Myiarchus nugator y Stilpnia cucullata. En 2018 y 2019 llevamos a cabo puntos de conteo con muestreo de distancia (n = 199) en hábitats boscosos y agrícolas de toda Granada para estimar la distribución y la abundancia relativa de las especies de aves residentes (n = 1.235 detecciones). Para las especies con más de 30 observaciones, estimamos la densidad utilizando modelos de distancia jerárquica, que incluyeron covariables de hábitat sitio específicas de la cobertura del suelo y la elevación. Durante nuestros muestreos detectamos más del 90% (n = 32) de las especies de aves terrestres registradas previamente. El recambio de especies fue bajo en comparación con un estudio similar realizado en la década de 1980, con una diferencia de cuatro especies entre ambos. Estas diferencias podrían atribuirse a introducciones recientes, estacionalidad, intensidad de muestreo u otras diferencias metodológicas. Recopilamos suficientes observaciones para estimar la densidad de nueve especies residentes, incluyendo el endémico Orthorhyncus cristatus (1,68 ind./ ha), Stilpnia cucullata (1,02 ind./ha), Loxigilla noctis (0,73 ind./ha) y Myiarchus nugator (0,59 ind./ha). Nuestros resultados propor- cionan una línea base importante para futuros trabajos de monitoreo y conservación, incluido el seguimiento de los impactos del cambio climático, la prestación de servicios ecosistémicos o el cambio de uso del suelo. Palabras clave Caribe, conservación de aves, densidad poblacional, endémico, modelo jerárquico de población, muestreo de distancia, recambio de especies, uso del hábitat Résumé Estimation de l’abondance et de la densité des oiseaux terrestres sur l’île de la Grenade • Dans l’ensemble de la Caraïbe, les oiseaux terrestres sédentaires ont fait l’objet de recherches relativement plus limitées que les espèces migratrices. En particulier sur l’île de la Grenade, il existe une incertitude quant au statut de plusieurs espèces endémiques régionales, notamment le Tyran bavard (Myiarchus nugator) et le Caliste dos-bleu (Stilpnia cucullata). Nous avons réalisé des dénombrements ponctuels par distance sampling (n = 199) dans des habitats forestiers et agricoles à travers la Grenade en 2018 et 2019 pour estimer la répartition et l’abondance relative des espèces d’oiseaux sédentaires (n = 1235 détections). Pour les espèces ayant fait l’objet de plus de 30 observations, nous avons estimé la densité spécifique à l’aide de modèles de distance hiérarchiques, incluant les covariables d’habitat propres au site que sont la couverture végétale et l’altitude. Nous avons détecté plus de 90 % (n = 32) des espèces d’oiseaux terrestres précédemment enregistrées au cours de nos comptages. Le renouvellement des espèces était faible par rapport à un dénombrement similaire réalisé dans les années 1980, avec une différence de quatre espèces entre les deux études. Cette variation pourrait être attribuée à des introductions récentes, à la saisonnalité, à l’intensité de l’échantillonnage ou à d’autres différences méthodologiques entre ces comptages. Nous avons fait suffisamment d’observations pour estimer la densité de neuf espèces sédentaires endémiques, dont le Colibri huppé (Orthorhyncus cristatus ; 1,68 ind./ha), le Caliste dos-bleu (1,02 ind./ha), le Sporophile rouge-gorge (Loxigilla noctis ; 0,73 ind./ha), et le Tyran bavard (0,59 ind./ha). Nos résultats constituent une base de référence importante pour les futurs travaux de suivi et de conservation, notamment pour les suivis des conséquences du changement climatique, de la fourniture de services écosystémiques ou du changement d’utilisation des terres. Mots clés Caraïbes, conservation des oiseaux, densité de population, distance sampling, endémisme, modèle hiérarchique de population, renouvellement des espèces, utilisation de l’habitat

show abstract

Section: Fig 2 Pearson Residuals Of Expectedsupporting

confidence: 63%

Section: Fig 2 Pearson Residuals Of Expectedmentioning

confidence: 99%

Abundance and density estimates of landbirds on Grenada

Devenish‐Nelson

Nelson

2021

JCO

View full text Add to dashboard Cite

show abstract

“…Our results show that iguana abundance is surprisingly relatively high in this habitat type. We note that the patch covered by our survey efforts appears of higher quality than the remainder of this habitat type on the south‐western side of the island, which is heavily grazed by free‐roaming herbivores (Madden, 2020; van Andel et al, 2016). Namely, the included patch has larger trees, is less degraded, and lies adjacent to secondary roads and semi‐urban development.…”

Section: Discussionmentioning

confidence: 97%

Hurricane‐associated population decrease in a critically endangered long‐lived reptile

et al. 2022

View full text Add to dashboard Cite

Catastrophic events, like hurricanes, bring lethal conditions that can have population‐altering effects. The threatened Caribbean dry forest occurs in a region known for its high‐intensity hurricane seasons and high species endemism, highlighting the need to better understand hurricane impacts in combination with habitat fragmentation and loss. However, such studies remain rare and for reptiles are mostly restricted to Anolis. Here, we used single‐season occupancy modeling to infer the impact of the intense 2017 Atlantic hurricane season on the critically endangered Lesser Antillean Iguana, Iguana delicatissima. We surveyed 30 transects across eight habitats on St. Eustatius during 2017–2019, which resulted in 344 individual surveys and 98 iguana observations. Analyses of abundance and site occupancy indicated both measures for 2018 and 2019 were strongly reduced compared to the pre‐hurricane 2017 state. Iguanas at higher elevations were affected more profoundly, likely due to higher wind speeds, tree damage, and extensive defoliation. Overall, our results indicate a decrease in population estimates (23.3%–26.5%) and abundance (22%–23.8%) for 2018 and 2019, and a 75% reduction in opportunistic sightings of tagged iguanas between 2017 and 2018. As only small and isolated I. delicatissima populations remain, our study further demonstrates their vulnerability to stochastic events. Considering the frequency and intensity of hurricanes are projected to increase, our results stress the urgent need for population‐increasing conservation actions in order to secure the long‐term survival of I. delicatissima throughout its range. Given the projected increase and poleward shift of hurricanes, our study provides important insights from a non‐model species.

show abstract

“…S1; Burke and DiTommaso 2011, Vandebroek et al 2018). The invasion of A. leptopus on St. Eustatius is among the most severe infestations of the species in the world (Ernst and Ketner 2007, Burke and DiTommaso 2011), and this invasion may contribute to vegetation changes that affect organisms at higher trophic levels in the food web (Jesse et al 2020, Madden and Van Zanten 2020). In a previous study, a high spatial resolution (2 × 2 m pixels) distribution map of A. leptopus on St. Eustatius was produced (Fig.…”

Section: Methodsmentioning

confidence: 99%

Spatially explicit removal strategies increase the efficiency of invasive plant species control

Eppinga

Baudena

Haber

et al. 2021

Ecological Applications

View full text Add to dashboard Cite

Effective management strategies are needed to control expansion of invasive alien plant species and attenuate economic and ecological impacts. While previous theoretical studies have assessed optimal control strategies that balance economic costs and ecological benefits, less attention has been paid to the ways in which the spatial characteristics of individual patches may mediate the effectiveness of management strategies. We developed a spatially explicit cellular automaton model for invasive species spread, and compared the effectiveness of seven control strategies. These control strategies used different criteria to prioritize the removal of invasive species patches from the landscape. The different criteria were related to patch size, patch geometry, and patch position within the landscape. Effectiveness of strategies was assessed for both seed dispersing and clonally expanding plant species. We found that, for seed-dispersing species, removal of small patches and removal of patches that are isolated within the landscape comprised relatively effective control strategies. For clonally expanding species, removal of patches based on their degree of isolation and their geometrical properties comprised relatively effective control strategies. Subsequently, we parameterized the model to mimic the observed spatial distribution of the invasive species Antigonon leptopus on St. Eustatius (northern Caribbean). This species expands clonally and also disperses via seeds, and model simulations showed that removal strategies focusing on smaller patches that are more isolated in the landscape would be most effective and could increase the effectiveness of a 10-yr control strategy by 30-90%, as compared to random removal of patches. Our study emphasizes the potential for invasive plant species management to utilize recent advances in remote sensing, which enable mapping of invasive species at the high spatial resolution needed to quantify patch geometries. The presented results highlight how this spatial information can be used in the design of more effective invasive species control strategies.

show abstract

Monitoring of terrestrial avifauna in six habitats on St. Eustatius, Caribbean Netherlands, 2009–2017

Cited by 6 publications

References 33 publications

Abundance and density estimates of landbirds on Grenada

Abundance and density estimates of landbirds on Grenada

Hurricane‐associated population decrease in a critically endangered long‐lived reptile

Spatially explicit removal strategies increase the efficiency of invasive plant species control

Contact Info

Product

Resources

About