Browsing by Author "McEntee, Jay P."

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    Disperser Limitation and Recruitment of an Endemic African Tree in a Fragmented Landscape
    (Wiley, 2009-04) Cordeiro, Norbert J.; Ndangalasi, Henry J.; McEntee, Jay P.; Howe, Henry
    Forest fragmentation may have positive or negative effects on tropical tree populations. Our earlier study of an endemic African tree, Leptonychia usambarensis (Sterculiaceae), in the East Usambara Mountains of Tanzania, found poorer recruitment of seedlings and juveniles in small fragments compared to continuous forest, and concomitant reduction of seed-dispersal agents and seed dispersal. However, the possibility that other biotic or abiotic consequences of the fragmentation process contribute to diminished recruitment in fragments was left open. Here we test whether excessive seed predation, diminished fecundity, low seed quality, or adverse abiotic effects acted independently or in concert with reduced seed dispersal to limit seedling and juvenile recruitment in fragments. Extended observations of disperser activity, a seed placement experiment, seed predator censuses, and reciprocal seedling transplants from forest and fragment sources failed to support the alternative hypotheses for poorer seedling and juvenile recruitment in fragments, leaving reduced seed dispersal as the most plausible mechanism. Poorer recruitment of this species in forest fragments, where high edge-to-area ratios admit more light than in continuous forest, is particularly striking because the tree is an early successional species that might be expected to thrive in disturbed microhabitats.
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    evo12950-sup-0001-SuppMat
    (2016-05) McEntee, Jay P.; Peñalba, Joshua V.; Werema, Chacha; Mulungu, Elia; Mbilinyi, Maneno; Moyer, David; Hansen, Louis A.; Fjeldså, Jon; Bowie, Rauri C. K.
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    Preliminary observations on the avifauna of Ikokoto Forest, Udzungwa Mountains, Tanzania
    (2013-05) Werema, Chacha; McEntee, Jay P.; Mulungu, Elia; Mbilinyi, Maneno
    A study was conducted at c. 110 ha of Ikokoto forest using mist-netting and general field observations. Sixty-four species were recorded of which 61% were of conservation importance in terms of forest dependence. All species were found to belong to the familiar assembly of the large Udzungwa forests. Six species, the Green-throated Greenbul Andropadus fusciceps, Spot-throat Modulatrix stictigula, African Tailorbird Artisornis metopias, Black-lored Cisticola Cisticola nigriloris, Uhehe Fiscal Laniarius marwitzi and Fülleborn's Black Boubou Laniarius fuelleborni detected are restricted range and one species Moreau's Sunbird Nectarinia moreaui is nearthreatened according to IUCN threat status. The presence of many species which are forest dependent in this tiny forest indicates that this site, though small in size and highly fragmented, retains significant conservation value for birds.
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    Social selection parapatry in an Afrotropical sunbird
    (Wiley, 2016-05) McEntee, Jay P.; Peñalba, Joshua V.; Werema, Chacha; Mulungu, Elia; Mbilinyi, Maneno; Moyer, David; Hansen, Louis A.; Fjeldså, Jon; Bowie, Rauri C. K.
    The extent of range overlap of incipient and recent species depends on the type and magnitude of phenotypic divergence that separates them, and the consequences of phenotypic divergence on their interactions. Signal divergence by social selection likely initiates many speciation events, but may yield niche-conserved lineages predisposed to limit each others' ranges via ecological competition. Here we examine this neglected aspect of social selection speciation theory in relation to the discovery of a non-ecotonal species border between sunbirds. We find that Nectarinia moreaui and N. fuelleborni meet in a ∼6 km wide contact zone, as estimated by molecular cline analysis. These species exploit similar bioclimatic niches, but sing highly divergent learned songs, consistent with divergence by social selection. Cline analyses suggest that within-species stabilizing social selection on song-learning predispositions maintains species differences in song despite both hybridization and cultural transmission. We conclude that ecological competition between moreaui and fuelleborni contributes to the stabilization of the species border, but that ecological competition acts in conjunction with reproductive interference. The evolutionary maintenance of learned song differences in a hybrid zone recommend this study system for future studies on the mechanisms of learned song divergence and its role in speciation. This article is protected by copyright. All rights reserved.