Management Implications of spatial and ecosystem thinking

Topic: Management implications of spatial and ecosystem thinking

Readings: Wiplfi and Baxter 2010

Fausch et al. 2002

Summary of readings

Fausch et al. 2002

-This paper addresses the importance of viewing streams as continuous, hierarchical, heterogeneous, and linear. It emphasizes that streams contain a mosaic of different types of habitat that are utilized by different species and lifestages through time.

-Historically research was conducted at the reach scale; however, advances in technology and a better understanding of fish movement requires us to look at habitat at larger spatial scales. For example, the presence of an adult trout in one reach might have more to do with its ability to find suitable habitat in other areas of the stream or ocean (rearing habitat) as it ages and moves (corridors) rather than the physical characteristics of that reach.

-The suggested new approach for research and conservation

1. Research must be conducted at appropriate scales for the questions of interest.

2. The importance of different physical and ecological processes will be revealed at

different spatiotemporal scales, and processes will interact.

(The availability of habitat is driven by processes at different spatial scales, which all

must meet the requirements for a species to persist)

3. Rare or unique features in a riverscape, either in space or time, can have overriding

effects on stream fishes.

(ex. a beaver pond may provide habitat (source) for different species that migrate to

other parts of the stream (sink) or a fire that occurs rarely may deposit wood in the

stream that affects the overall stream community).

4. unintended consequences of habitat degradation will occur in all directions, including

upstream. (fish move upstream and downstream and are affected by disturbance

throughout the habitat they encounter)

5. Fisheries ecologists who study stream fishes must strive to make observations and test

predictions at the scale at which managers effect change.

Overall research and management must address problems at the appropriate scale, which is often larger than a stream reach.

Wipfli and Baxter 2010

-This paper also underscores the importance of maintaining connectivity among the entire stream but focuses on energy requirements rather than the physical characteristics of the stream.

-Depending on where you are in the river continuum the fauna receive food (energy and nutrients) from somewhere else in the stream.

-examples-Local primary and secondary production may be subsidized by…..

-Tributaries– even food from small fishless streams is washed downstream.

-Terrestrial– riparian inputs such as leaves and terrestrial insects

-Marine – Migrating fishes from the sea

-These imputs vary by season and often life histories are synchronized with the availability of said inputs.

-Overall it is easy to focus on the physical habitat within a stream, but the amount of energy in a system may also limit the presence and abundance of stream fish. These imputs come from areas other than the focal area, which highlights the importance of both terrestrial and stream connectivity to a system.

Most relevant discussion questions

1. At what spatial and temporal scales do most habitat studies occur and at what scales do most natural processes and human effects occur?

2. What is meant by the intermediate habitat scale and what makes it so tough to study at this scale?

3. Is the intermediate habitat scale the same for all species?

4. How might downstream events affect upstream community assemblages?

5. What restoration challenges occur at larger spatial scales?

Thinking about habitat patchiness and connectivity at multiple spatial scales can get confusing, but overall the class seemed to comprehend the material.