quantifing secondary succession

quantifing secondary succession - COMMUNITY ECOLOGY 4(2):...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Introduction The composition of many plant communities changes over time, often following a transition from one form to another, a progression labeled succession. In some cases, this progression proceeds from an initial state to a final state, while in other cases it can be described as cyclical (Grosshans and Kenkel 1997, Armstrong and Bullock 2003), oscillating between 2 states. Regardless if a spe- cific community is typically viewed as linear, moving from initial state to final state, or cyclical, moving from state 1 to state 2, then back to state 1, the process of suc- cession is directional; communities are moving from one set of species to another. Several measures have been pro- posed to capture the position of the community along this process. A simple, easy to calculate measure can provide a useful summary for comparative purposes. We propose the use of a ratio of the species found in the initial state (early species) to those not found in the initial state (late species). Once the community members have been as- signed to the early or late groups, this ratio can be used to compare the rate of succession between different sites, ex- ploring the impact of site specific characteristics or events on this rate. The benefit of such an aggregate measure is that it is simple to calculate, easy to interpret and amena- ble to correlation between other variables such as herbi- vore dynamics or soil characteristics. Plant communities occupy a spatially defined region. For most communities, identifying replicates within the area occupied by the community is difficult due to spatial heterogeneity with respect to soil characteristics, sur- rounding vegetation, seed bank, and herbivore pressure. When long term community dynamics are studied, appro- priate sites may be spatially or temporally isolated, further complicating the potential for replication. To address these issues, studies have sought numerous collections of community data for pattern analysis (Wildi and Schütz 2000). The general result of these studies is that the length of time and specific pathway toward the endpoint commu- nity, as defined by Pickett (1989), is difficult to predict. However, it has been shown to depend upon initial com- munity composition and soil characteristics (Pickett 1982, Myster and Pickett 1994). The difficulty in achieving ac- curate predictions stems largely from the fact that commu- nities tend to be complex, containing a mixture of numer- ous species (Anand and Orlóci 1997, Anand 2000). Within this community, plant species will exhibit a range of tolerances for drought, sunlight, nutrients, competition and herbivory. However, despite the complexity and irre- C OMMUNITY E COLOGY 4(2): 141-156, 2003 1585-8553/$20.00 © Akadémiai Kiadó, Budapest Quantifying secondary succession: a method for all sites?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/18/2011 for the course ENVS 200 taught by Professor Annegrant during the Fall '11 term at Waterloo.

Page1 / 16

quantifing secondary succession - COMMUNITY ECOLOGY 4(2):...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online