|
|
Non-native species
Biodiversity Conservation
|
[participants] [selected publications]
Biogeographers have long noted that different regions of the globe are characterized by different biotas, reflecting evolutionary divergence of species along with past migrations. Particularly since 1500, however, humans have facilitated the mixing of these separate biotas, resulting in a loss of regional diversity and an increased homogenization of floras and faunas. Such facilitated invasions of non-native species rank high among the factors most responsible for current population and species extinctions. Conversely, non-natives may also provide habitat or resources for native species, altering local species interactions.
CCB researchers are studying factors that influence the degree to which non-natives cause local extinctions and/or alter community or ecosystem structure and function. First, the degree of "invasiveness" is important. How readily does the non-native species spread in the new habitat, and to what extent does it come to dominate the community or ecosystem? Second, to what extent does the non-native invade or disrupt inter-specific interactions, such as predator/prey, competition, or various types of mutualisms, including pollination? The answer to this question may determine the extensiveness of the effect of the non-native at the community and ecosystem level, and in so doing, feed back to influence our perception of its invasiveness.
Once a non-native has successfully invaded a region, the changes to inter-specific interactions may result in changes in the population dynamics, ecology and evolutionary trajectory of both the invader and the invaded community. Can we predict when these changes should be extreme, and when they should be minor? Is it possible for natives to adapt evolutionarily to the invader, and avoid its impacts? Along similar lines, once the non-native is established, what are the ramifications for native species of non-native eradication and habitat restoration?
Our current work uses several study systems.
- One, led by Carol Boggs with Paul Ehrlich and Steve Burke as collaborators, focuses on an introduced population of Gillette’s checkerspot butterfly in
Colorado
. We are addressing questions concerning the control of recently introduced population’s structure and dynamics, and interaction with local species.
- Second, Boggs is examining the ecological and evolutionary dynamics of a native butterfly in response to invasion by a non-native potential larval host plant, again in
Colorado
. Since native larvae can’t eat the plant, although females oviposit on it, this system represents disruption of a coevolved relationship by a non-native. The case study should be capable for expansion to other species in which a native herbivore or parasite is polyphagous and sufficiently widely distributed that local adaptation to natives is possible.
- Third, in collaboration with scientists and land managers in
Nevada
, Erica Fleishman is testing whether different native and invasive vegetation associations influence the occurrence patterns and community dynamics of butterflies and birds along the
Muddy
River
in
Clark County
,
Nevada
. This project will examine ecological ramifications of introduction and removal of invasive salt-cedar (Tamarix spp.) in the
Mojave Desert
ecoregion.
________________________________________________________
Participants
- Carol Boggs
- Erica Fleishman
- John Fay
- Alan Launer
- Paul Ehrlich
- Steve Burke
- Diane Debinski
- Ernest Williams
Publications
Fleishman, E., G.T. Austin, P.F. Brussard, and D.D. Murphy. 1999. A comparison of butterfly communities in native and agricultural riparian habitats in the Great Basin. Biological Conservation 89:209-218.
Fleishman, E., D.D. Murphy, T. Floyd, N. McDonal, and J. Walters. 2002. Characterization of riparian bird communities in a Mojave Desert watershed. Great Basin Birds 5:38-44.
Fleishman, E., C. Ray, P. Sjögren-Gulve, C.L. Boggs, and D.D. Murphy. 2002. Assessing the relative roles of patch quality, area, and isolation in predicting metapopulation dynamics. Conservation Biology 16:706-716.
Fleishman, E., C.J. Betrus, and R.B. Blair. 2003. Effects of spatial scale and taxonomic group on partitioning of butterfly and bird diversity in the Great Basin. Landscape Ecology 18:675-685.
Fleishman, E., N. McDonal, R. Mac Nally, D.D. Murphy, J. Walters, and T. Floyd. 2003. Effects of floristics, physiognomy, and non-native vegetation on riparian bird communities in a Mojave Desert watershed. Journal of Animal Ecology 72:484-490.
Mac Nally, R., E. Fleishman, L. Bulluck, and C. Betrus. 2004. Comparative influence of spatial scale on beta diversity within regional assemblages of birds and butterflies. Journal of Biogeography 31:917-929.
Mac Nally, R., E. Fleishman, and D.D. Murphy. 2004. Influence of temporal scale of sampling on detection of relationships between invasive plants and the diversity patterns of plants and butterflies. Conservation Biology 18:in press.
Fleishman, E., R. Mac Nally, and D.D. Murphy. In press. Relationships among non-native plants, diversity of plants and butterflies, and adequacy of spatial sampling. Biological Journal of the Linnean Society.
Fleishman, E. and D.D. Murphy. In press. Biodiversity patterns of spring-associated butterflies in a Mojave Desert mountain range. Journal of the Lepidopterists' Society.
Sada, D.W., E. Fleishman, and D.D. Murphy. In press. Response of spring-dependent aquatic assemblages to environmental and land use gradients in a Mojave Desert mountain range. Diversity and Distributions.
|
