Directed dispersal of Opuntia species in the Karoo, South Africa: are crows the responsible agents?

Dean, W. R. J.; Milton, Suzanne J.

doi:10.1006/jare.2000.0652

Cited by 63 publications

(54 citation statements)

References 5 publications

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“…Thus, species that are restricted to highly patchy habitats may require dispersal methods that are especially efficient at dispersing to those patches (directed dispersal). Birds and mammals have been found to preferentially disperse seeds to favourable microsites for germination (Wenny and Levey 1998;Dean and Milton 2000;Purves and Dushoff 2005;Briggs et al 2009). Therefore, in patchy habitats directed vertebrate dispersal may be expected to be more common, whilst the frequency of less directed dispersal syndromes, such as wind dispersal, may be lower (Howe and Smallwood 1982;Wenny 2001;Spiegel and Nathan 2010).…”

Section: Introductionmentioning

confidence: 99%

Patterns of seed dispersal syndromes on serpentine soils: examining the roles of habitat patchiness, soil infertility and correlated functional traits

Spasojevic

Damschen

Harrison

2012

Plant Ecology & Diversity

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Section: Introductionmentioning

confidence: 99%

Patterns of seed dispersal syndromes on serpentine soils: examining the roles of habitat patchiness, soil infertility and correlated functional traits

Spasojevic

Damschen

Harrison

2012

Plant Ecology & Diversity

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“…Among passerines, Corvus spp. (crows) regularly produce pellets (Berrow et al 1992, Dean and Milton 2000, Kurosawa et al 2003. Barrows and Schwarz (1895) described pellet production in Corvus brachyrhynchos Brehm (American Crow).…”

Section: Introductionmentioning

confidence: 99%

Crow Pellets from Winter Roosts in Lancaster, Pennsylvania

Annala

Tillman

Backus

et al. 2012

Northeastern Naturalist

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-Although crows cast pellets, there is little quantitative information on pellets from Corvus brachyrhynchos (American Crow), and none from C. ossifragus (Fish Crow). During a study of crow roost dispersal in Lancaster, PA, we collected samples of pellets from several locations. By mass, pellets consisted mostly of grit and other fi ne inorganic material, various seeds (principally Toxicodendron radicans [Poison Ivy] and Celtis occidentalis [Common Hackberry]), and vegetation remnants. Six pellets contained small-mammal bones. Because the Lancaster winter crow population included many Fish Crows, the source of the pellets was not certain. To clarify this, we compared the size of the Lancaster crow pellets to those produced by captive Fish Crows, and we provide the fi rst quantitative description of pellets for either species. Our size comparisons suggest that >90% of the pellets in our sample from Lancaster were produced by American Crows.

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“…In 1942, Opuntia plantations have covered an area of 9000 km 2 in the Karoo and the savannas of South Africa. And only in the late 20th century, this plant has become a real agricultural catastrophe (Dean & Milton, 2000). In order to spread over the Australian territory and to become a real ecological catastrophe there, Opuntia species took time about 140 years (from 1789 to 1925) (Frawley, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…The invasion of Opuntia ficus-indica (L.) Mill. in South Africa in the 1990s has led to a significant agricultural crisis in this region (Dean & Milton, 2000).…”

Section: Introductionmentioning

confidence: 99%

Invasion of Opuntia humifusa and O. phaeacantha (Cactaceae) into plant communities of the Karadag Nature Reserve

Fateryga¹,

Багрикова²

2017

Nat. Cons. Res.

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The results of a study of Opuntia humifusa and O. phaeacantha naturalised in the Karadag Nature Reserve (southeastern part of the Crimean Peninsula) are presented. There, the largest coenopopulations of Opuntia plants are confined to the «biostation» territory (bordering with the park, administrative buildings and housing estate). Twelve localities were described in the Karadag Reserve. These differ by phytocoenotic characteristics, area and floristic composition. Seven localities include only O. humifusa plants; four ones include only O. phaeacantha individuals; and both the species are present on the twelfth locality. The total number of individuals of each species and ontogenetic structure of the population were studied in each locality. The total number of O. humifusa individuals in the Karadag Reserve is more than 600 plants within the «biostation» territory, while the total number of O. phaeacantha plants is about 400 individuals. Studying of the plant communities has been carried out according to the Braun-Blanquet method. Opuntia plants form derivate communities within degraded steppes, phryganoid-steppes, and semi-desert badland phytocoenoses almost at all studied localities. A significant number of synanthropic species (including alien plants) was found within these communities. Opuntia plants are able to self-reproduce predominantly vegetatively. Self-seeding reproduction occurs less frequently. Both species can be considered as invasive plants because they have a high adaptive capacity.

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Directed dispersal of Opuntia species in the Karoo, South Africa: are crows the responsible agents?

Cited by 63 publications

References 5 publications

Patterns of seed dispersal syndromes on serpentine soils: examining the roles of habitat patchiness, soil infertility and correlated functional traits

Patterns of seed dispersal syndromes on serpentine soils: examining the roles of habitat patchiness, soil infertility and correlated functional traits

Crow Pellets from Winter Roosts in Lancaster, Pennsylvania

Invasion of Opuntia humifusa and O. phaeacantha (Cactaceae) into plant communities of the Karadag Nature Reserve

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