Sierra Nevada Aquatic Research Laboratory

28 Aug, 10 AM - 03 Sep, 10 AM

Dan - We do not yet know what field sites we'll use, and part of this first trip is to establish those for a new NSF grant. However, our impacts will be minimal ... all we'll be doing is placing standard tile-like substrates in 30-50 streams that have differing numbers of algal species, allow periphyton to develop for 4-8 weeks, and then return to sample algae and measure primary production. My needs are simply for housing during this time. The abstract from the NSF proposal is below: Ecologists have long studied how the productivity of ecosystems limits species diversity, but the converse question of how diversity controls production has recently emerged as a prominent topic of research. In part, this latter question has been prompted by accelerating rates of extinction and invasion that reduce and homogenize species pools, requiring us to better understand the ecological consequences of diversity loss. Studies to date have greatly advanced our understanding of how, when and why species diversity can affect primary production. Even so, these studies have been limited in scope, focused mostly on randomly assembled communities of grassland species placed together in experimental units that are spatially homogeneous and isolated from external processes such as disturbance and dispersal. In fact, it seems safe to say that most studies have worked hard to eliminate forms of spatial and temporal heterogeneity that might increase experimental ?noise?. But these forms of heterogeneity are potentially the same ones that maintain diversity in the first place, and theory suggests they are necessary for species to express niche differences that affect resource capture and production. Recent models even argue that diversity per se will only influence productivity in a variable environment where taxa have full opportunity to express niche differences. Here I propose to add heterogeneity back into our work on diversity-function relationships by examining how key aspects of spatial and temporal variation moderate the impacts of species diversity on primary production. I will take an empirical approach focusing on stream periphyton (benthic algae) as a model system. Periphyton are a useful system for the proposed work because the diversity and composition of algae in streams are known to be structured by spatial heterogeneity in flow, and by patchy disturbances that intermittently scour substrates. My objectives are: 1. To assess how spatial heterogeneity affects primary production via its control over diversity and the turnover of species composition among habitat patches. 2. To determine how intermittent disturbance, and the subsequent process of re-colonization of patches, can moderate the impacts of diversity on primary production. I will first conduct laboratory experiments to determine how the diversity of algae affects productivity when species disperse across patches having spatially homo- vs. heterogeneous flow conditions and differing probabilities of disturbance. Then, in field experiments I will manipulate flow heterogeneity and substrate scour in riffle habitats in streams spanning a large natural gradient in algal diversity. While each study has individual strengths and weaknesses, together they span two scales of biological realism designed to link mechanistic process to naturally occurring patterns in the field.

Visit #10092 @Sierra Nevada Aquatic Research Laboratory

Approved

Under Project # 6793 | Research

Effects of stream algal diversity on primary production and nutrient cycling

faculty - University of California, Santa Barbara

Reservation Members(s)

Bradley Cardinale Aug 28 - Sep 3, 2006 (7 days)
Bradley Cardinale Aug 28 - Sep 3, 2006 (7 days)
Bradley Cardinale Aug 28 - Sep 3, 2006 (7 days)

Reserve Resources(s) | Create Invoice

Dorm 3 Aug 28 - Sep 3, 2006
Q1 3 Aug 28 - Sep 3, 2006
Q2 3 Aug 28 - Sep 3, 2006
Q3 3 Aug 28 - Sep 3, 2006
Q8 3 Aug 28 - Sep 3, 2006