scholarly journals Differences in insectivore bird diets in coffee agroecosystems driven by obligate or generalist guild, shade management, season, and year

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12296
Author(s):  
Julie A. Jedlicka ◽  
Stacy M. Philpott ◽  
Martha L. Baena ◽  
Peter Bichier ◽  
Thomas V. Dietsch ◽  
...  

Neotropical shade-grown coffee systems are renowned for their potential to conserve avian biodiversity. Yet, little is known about food resources consumed by insectivorous birds in these systems, the extent of resource competition between resident and migratory birds, or how management of shade trees might influence diet selection. We identified arthropods in stomach contents from obligate and generalist insectivorous birds captured in mist-nets at five coffee farms in Chiapas, Mexico between 2001–2003. Overall stomach contents from 938 individuals revealed dietary differences resulting from changes in seasons, years, and foraging guilds. Of four species sampled across all management systems, Yellow-green Vireo (Vireo flavoviridis) prey differed depending on coffee shade management, consuming more ants in shaded monoculture than polyculture systems. Diets of obligate and generalist resident insectivores were 72% dissimilar with obligate insectivores consuming more Coleoptera and Araneae, and generalist insectivores consuming more Formicidae and other Hymenoptera. This suggests that obligate insectivores target more specialized prey whereas generalist insectivores rely on less favorable, chemically-defended prey found in clumped distributions. Our dataset provides important natural history data for many Nearctic-Neotropical migrants such as Tennessee Warbler (Leiothlypis peregrina; N = 163), Nashville Warbler (Leiothlypis ruficapilla; N = 69), and Swainson’s Thrush (Catharus ustulatus; N = 68) and tropical residents including Red-legged Honeycreepers (Cyanerpes cyaneus; N = 70) and Rufous-capped Warblers (Basileuterus rufifrons; N = 56). With declining arthropod populations worldwide, understanding the ecological interactions between obligate and generalist avian insectivores gives researchers the tools to evaluate community stability and inform conservation efforts.

The Auk ◽  
1984 ◽  
Vol 101 (1) ◽  
pp. 53-58 ◽  
Author(s):  
John W. Parrish ◽  
James A. Ptacek ◽  
Kevin L. Will

Abstract Near-ultraviolet (UV) light reception was demonstrated for the first time in three species of nonmigratory emberizid and passerid birds. Behavioral data also established that eight additional alcedinid and emberizid birds can detect near-UV wavelengths. The finding that these more recently evolved species can see near-UV light implies that near-UV vision is probably an important visual capability in most, if not all, diurnal birds. Although the utility of near-UV reception for birds remains equivocal, the fact that nonmigratory as well as migratory birds can perceive UV suggests that birds may be able to utilize the UV spectrum for homing, orientation, and navigation, as do the UV-sensitive arthropods. It also can be inferred that UV vision may be especially useful to insectivorous birds for the detection of UV reflectance patterns, which many otherwise cryptic arthropods possess for mate recognition. Ultraviolet reflectance patterns also may be useful to frugivorous and nectarivorous birds for the detection of food items.


2003 ◽  
Vol 73 (2) ◽  
pp. 301-330 ◽  
Author(s):  
A. R. Ives ◽  
B. Dennis ◽  
K. L. Cottingham ◽  
S. R. Carpenter

2013 ◽  
Vol 40 (5) ◽  
pp. 507 ◽  
Author(s):  
Amaya Atucha ◽  
Ian A. Merwin ◽  
Michael G. Brown ◽  
Francisco Gardiazabal ◽  
Francisco Mena ◽  
...  

The effect of groundcover management systems on root demography and distribution of newly planted avocado (Persea americana Mill) trees was examined using minirhizotron techniques. We evaluated three groundcover systems: (1) bare soil (BS), pre- and post-emergence herbicides; (2) vegetation strip (VS), post-emergence herbicide applied in a 1-m wide strip centred on the tree row plus a groundcover mixture seeded between tree rows; and (3) complete groundcover (GC), covering the entire surface of the plots. Root production was higher in the non-bearing year (2009–10) than in the bearing year (2010–11). Trees in the BS plots had more roots of bigger diameter in the top 30 cm of soil and trees in VS and GC plots had more roots in the 30–60 cm depth and of smaller diameter. Lifespan of spring-born roots were 61 and 59% greater than those born during autumn and summer, respectively and soil depth and root diameter were positively correlated with root longevity. Lifespan of thinner roots (<0.2 mm) in the BS and VS plots were 49 and 33% greater than GC respectively. Avocado trees grown in contrasting condition compared with their native habitat show high morphological root plasticity, in response to resource and non-resource competition when grown in mixed stands.


2020 ◽  
Author(s):  
April D. Lamb ◽  
Catherine A. Lippi ◽  
Gregory J. Watkins-Colwell ◽  
Andrew Jones ◽  
Dan Warren ◽  
...  

AbstractHemidactylus spp. (House geckos) rank among the most successful invasive reptile species worldwide. Hemidactylus mabouia in particular has become ubiquitous across tropical urban settings in the Western Hemisphere. H. mabouia’s ability to thrive in close proximity to humans has led to the rapid displacement of native geckos in urban areas, however the mechanisms driving this displacement remain understudied. Here we combine data from nitrogen and carbon stable isotopes, stomach contents, and morphometric analyses of traits associated with feeding and locomotion to test alternate hypotheses of displacement between H. mabouia and a native gecko, Phyllodactylus martini, on the island of Curaçao. Consistent with expectations of direct food resource competition, we demonstrate substantial overlap of invertebrate prey resources between the species. Additionally, we found strong evidence from both diet content and stable isotope analyses that H. mabouia acts as a vertebrate predator, preying upon P. martini as well as other native and non-native reptiles. Finally, we show that H. mabouia possesses several morphological advantages, including larger sizes in feeding-associated traits and limb proportions that could offer a propulsive locomotor advantage on vertical surfaces. Together, these findings suggest the successful establishment of H. mabouia likely involves a combination of both exploitative interspecific competition and predation. Given the ubiquity of H. mabouia, illuminating the role of this species as both a competitor and a predator casts new concerns on the ecological and demographic impacts of this widespread urban invader.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4036 ◽  
Author(s):  
Javier Manjarrez ◽  
Martha Pacheco-Tinoco ◽  
Crystian S. Venegas-Barrera

The Mexican Garter Snake (Thamnophis eques)is a terrestrial-aquatic generalist that feeds on both aquatic and terrestrial prey. We describe size-related variation and sexual variation in the diet ofT. equesthrough analysis of 262 samples of identifiable stomach contents in snakes from 23 locations on the Mexican Plateau. The snakeT. equeswe studied consumed mostly fish, followed in lesser amounts by leeches, earthworms, frogs, and tadpoles. Correspondence analysis suggested that the frequency of consumption of various prey items differed between the categories of age but not between sex of snakes, and the general pattern was a reduction of prey item diversity with size of snake. Snake length was correlated positively with mass of ingested prey. Large snakes consumed large prey and continued to consume smaller prey. In general, no differences were found between the prey taxa of male and female snakes, although males ate two times more tadpoles than females. Males and females did not differ in the mass of leeches, earthworms, fishes, frogs and tadpoles that they ate, and males and females that ate each prey taxon were similar in length. We discuss proximate and functional determinants of diet and suggest that the observed intraspecific variation inT. equescould be explored by temporal variation in prey availability, proportions of snake size classes and possible sexual dimorphism in head traits and prey dimensions to assess the role of intersexual resource competition.


2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Alicia Montesinos-Navarro ◽  
Gisela Díaz ◽  
Pilar Torres ◽  
Fuensanta Caravaca ◽  
Antonio Roldán

AbstractAlthough ecological networks are usually considered a static representation of species’ interactions, the interactions can change when the preferred partners are absent (rewiring). In mutualistic networks, rewiring with non-preferred partners can palliate extinction cascades, contributing to communities’ stability. In spite of its significance, whether general patterns can shape the rewiring of ecological interactions remains poorly understood. Here, we show a phylogenetic constraint in the rewiring of mycorrhizal networks, so that rewired interactions (i.e., with non-preferred hosts) tend to involve close relatives of preferred hosts. Despite this constraint, rewiring increases the robustness of the fungal community to the simulated loss of their host species. We identify preferred and non-preferred hosts based on the probability that, when the two partners co-occur, they actually interact. Understanding general patterns in the rewiring of interactions can improve our predictions of community responses to interactions’ loss, which influences how global changes will affect ecosystem stability.


2012 ◽  
Vol 5 (1) ◽  
pp. 39-43
Author(s):  
Rohtash Chand Gupta ◽  
Tirshem Kumar Kaushik

Hathnikund is a place in Yamunanagar District in Haryana where Yamuna Rivers forms a sort of Lake over raised plinth after descending into plains from Himalayas nearby Ponta Sahib town near Haryana-Himachal Border. At the same time, Tajewala Barrage is one more pool like scenic place where waters of Western Yamuna Canal are collected by Govt. of Haryana for subsequent multipurpose. In the present studies, wetland bird’s diversity of Hathnikund has been recorded, analyzed and interpreted. The studies were conducted for a period of three years (September 2005-March 2008) during winter season only. The present studies revealed that in all 47 species of wetland birds belonging to 9 orders and 13 families were observed during September 2005-March 2011. Out of these 47 species of wetland birds, 26 species were Winter Migratory, 13 Resident and 9 species were Local Migratory. In so far as Abundance Status is concerned, 26 species of birds were Common, Nine species were UnCommon, Seven Species of birds were Very Common and five species were Rare. Truely winter migratory birds observed belong to Orders, Ciconiiformes, Anseriformes and Chardriiformes. Prominent migratory birds include, amongst others, Bar-headed Goose Anser indicus, Brahminy Shelduck Tadorna ferruginea, Gadwall Anas strepera, Eurasian Wigeon Anas penelope, Mallard Anas platyrhynchos, Northern Pintail Anas acuta, Northern Shoveller Anas clypeata, Red-crested Pochard Rhodonessa rufina, Common Pochard Aythya ferina, Tufted Pochard Aythya fuligula which come to Hathini Kund during winter from far off places like Russia, Siberia, South and East Asia, China and Caspian region. It is recommended that Hathnikund be further promoted as Winter Halting Place for migratory birds by adding islands within the Water Sheet, the construction of wide margins on the peripheral zones and a rich canopy of endemic trees by implanted in plenty. It is further recommended that Eco-tourism facilities be generated at Hathnikund, linking biodiversity with society’s economic upliftment, employment and awareness. It is also recommended that Fish angling sport can be an added attraction to Bird Watching. In correlation with mystery-wrapped natural ambiences of Hathnikund, it can be sold to tourists of foreign origin thus generating exchange earning facility. As of today, no body known about Hathnikund except amateur bird watchers who turn out to be tourists too, if appropriate lodging boarding facilities are available.DOI: http://dx.doi.org/10.3126/ijls.v5i1.5953 International Journal of Life Sciences Vol.5(1) 2011 39-43


The Condor ◽  
2020 ◽  
Vol 122 (2) ◽  
Author(s):  
Laura Cardenas-Ortiz ◽  
Nicholas J Bayly ◽  
Kevin J Kardynal ◽  
Keith A Hobson

Abstract Migratory bottlenecks concentrate individuals and populations of Nearctic–Neotropical migrants from across vast breeding areas. The extent to which such concentrations occur has important ramifications for interpreting migratory connectivity and for the vulnerability of populations throughout the annual cycle but investigations of such phenomena are rare. We inferred breeding origins of 11 species of Nearctic–Neotropical migrants captured during fall migration in the Darién region, northwestern Colombia, using feather stable-hydrogen isotope values (δ 2Hf). Our objectives were to determine (1) the extent to which this region acts as a catchment for individuals from across a species’ breeding range, (2) if temporal patterns of arrival arise as a function of migration distance inferred from δ 2Hf, and (3) if phenological differences among species segregate populations. The Darién concentrated populations of 6 species, with individuals potentially derived from 78% to 94% of their respective North American breeding ranges. The catchment area for the remaining 5 species covered 40–72% of breeding ranges, with a bias in origin from the west (e.g., Northern Waterthrush [Parkesia noveboracensis], Swainson’s Thrush [Catharus ustulatus]), north or center (Yellow Warbler [Setophaga petechia]) of their range. Differential timing in the migration of populations occurred in 6 species, generating a degree of temporal segregation. In contrast, peak migration for all species occurred in October, resulting in high overlap among species in their use of the Darién. Overall, our results describe high mixing of populations in the Darién for several species, which, given the region’s highly restricted geographic extent, suggests that a bottleneck effect occurs; however, comparisons with other regions in Central America and northern South America are required. The combination of extensive population mixing and limited temporal segregation over a narrow geographical area suggests that long-distance migrants may be especially vulnerable to events occurring in such regions, including adverse weather conditions and anthropogenic land cover change.


2018 ◽  
Vol 5 (1) ◽  
pp. 171675 ◽  
Author(s):  
Jaroslav Koleček ◽  
Steffen Hahn ◽  
Tamara Emmenegger ◽  
Petr Procházka

Migratory birds often move significantly within their non-breeding range before returning to breed. It remains unresolved under which circumstances individuals relocate, whether movement patterns are consistent between populations and to what degree the individuals benefit from the intra-tropical movement (ITM). We tracked adult great reed warblers Acrocephalus arundinaceus from a central and a southeastern European breeding population, which either stay at a single non-breeding site, or show ITM, i.e. move to a second site. We related ITM to the normalized difference vegetation index (NDVI) describing vegetation conditions and probably reflecting food abundance for these insectivorous birds. Three-quarters of birds showed ITM across the non-breeding range. We found no difference in range values and mean values of NDVI between the single non-breeding sites of stationary birds and the two sites of moving birds. The vegetation conditions were better at the second sites compared to the first sites during the period which moving birds spent at the first sites. Vegetation conditions further deteriorated at the first sites during the period the moving birds resided at their second sites. Our study provides evidence that birds probably benefit from improved conditions after ITM compared to the conditions at the sites from where they departed.


2021 ◽  
Vol 17 (8) ◽  
pp. 20210200
Author(s):  
Kevin G. Young ◽  
Timothy R. H. Regnault ◽  
Christopher G. Guglielmo

Migratory birds experience bouts of muscle growth and depletion as they prepare for, and undertake prolonged flight. Our studies of migratory bird muscle physiology in vitro led to the discovery that sanderling ( Calidris alba ) muscle satellite cells proliferate more rapidly than other normal cell lines. Here we determined the proliferation rate of muscle satellite cells isolated from five migratory species (sanderling; ruff, Calidris pugnax ; western sandpiper, Calidris mauri ; yellow-rumped warbler, Setophaga coronata ; Swainson's thrush, Catharus ustulatus ) from two families (shorebirds and songbirds) and with different migratory strategies. Ruff and sanderling satellite cells exhibited rapid proliferation, with population doubling times of 9.3 ± 1.3 and 11.4 ± 2 h, whereas the remaining species' cell doubling times were greater than or equal to 24 h. The results indicate that the rapid proliferation of satellite cells is not associated with total migration distance but may be related to flight bout duration and interact with lifespan.


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