Resistance and Resilience of Lakes to Perturbations

1
Resistance and Resilience of Lakes to
Perturbations
2

• Resistance is the degree to which a system is
  altered when the environment changes

Resilience is the degree and rate of a systems
return to its previous configuration once the
disruption is removed
3
Why is knowing how do natural communities react
to perturbations important?

• Allows us to predict how biodiversity will be
  effected by
• Increased changes in habitat
• Invasion of ecosystems by exotic species
• If effects of can be reversed
• Largest problem in determining reactions of
  community
• Small temporal scales
• Small spatial scales
• Difficulty in extrapolating the above to entire
  landscapes and ecosystems

4
Research in the 1970s
Focused on particular species with ecosystems and
small scale response by these species Hall, D.
J., and E.E Werner. 1977. Seasonal distribution
and abundance of fish in the littoral zone of
Michigan lake. Transactions of the American
Fisheries Society 106 545-555 Hall, D. J., E.E
Werner, J.F. Gilliam, G.Ggt Mittelbach, D. Howard,
C.G. Doner, J.A. Dickerman and A.J. Stewart 1979.
Diel foraging behavior and prey selection in the
golden shiner (Notemigonus crysoleucas). Canadian
Journal of Fisheries and Aquatic Sciences
421608-1613 Haney, J.F., and D.J hall. 1975
Diel vertical migration and filter-feeding
activities in Daphnia. Archive fur hydobiologie
75 413-441
5
1980s and 1990s research explosion
Attempts in identifying specific interactions
that govern overall dynamics of
community Introduction of the idea of cascading
effects within lake communities Henrikson, L.,
H. Nyman, H. Oscarson, and J. Stenson. 1980.
Trophic changes, without changes in external
nutrient loading. Hydrobiologia 68
257-263. Power, M.E., W.J. Matthews, and A.J
Stewart. 1985. Grazing minnows, piscivorous bass
and stream algae dynamics of a strong
interaction. Ecology 66 1448-1456. Carpenter,
S.R., J.F. Kitchell, J.R. Hodgson, P.A. Cochran,
J.J Elser, M.M Elser, D.M. Lodge, D. Kretchmer,
X. He and C.N. von Ende. 1987. Regulation of lake
primary productivity by food-wed structure.
Ecology 681863-1876 Kerfoot, W.C., and A. Sih
1987. Predation. Direct and indirect impacts on
aquatic communities. University Press of New
England, Hanover, New Hampshire,
USA. Reinertsen, H., A. Jensen, J.I. Koksvik, A.
Langelaand, and Y.Olsen. 1990. Effects of fish
removal on the limnetic ecosystem of a eutrophic
lake. Canadian Journal of Fisheries and Aquatic
Science 47166-173. Elser, J.J and S.R.
Carpenter. 1999. Predation-driven dynamics of
zooplankton and phytoplankton comunities in a
whole-lake experiment. Oecologicia
76148-154. Carpenter, S.R. and J.F Kitchell.
1993. The trophic cascade in lakes, Cambridge
University Press, New York, New York, USA
6
What does all this mean?

• Knowing resistance of lakes allows us to
• Gives models for how similar lakes will be
  changed
• Predict effects of biodiversity on other lakes
• Can help us avoid disruption of lakes in the
  first place by knowing what factors affect them
  the most
• Knowing the resilience behavior of lakes can
• Give us models on how to reverse disruption
• Give us models on how to improve disrupted
  biodiversity

7
Perturbation and Resilience A Long-term,
Whole-Lake Study of Predator Extinction and
ReintroductionMittelbach, G. G, Turner, A. M.,
Hall, D. J., Rettig, J. E., and Osenberg, C. W.

• Goal
• To report the responses of fish and zooplankton
  dynamics to the removal and reintroduction of a
  top predator in the system
• Study Area
• Wintergreen Lake located on the W.K. Kellogg
  Biological Station in southwest Michigan
• Observations from 1951 -1988 were used and new
  data was collected in 1989, 1991 and 1993 by
  researchers
• Study lake was

• Hypereutrophic (due to the number of ducks and
  geese in area)
• Shallow (6.3 max depth and 2.5 m mean depth)
• A Hard water lake

8
History

• Between 1930 and 1965 sporadic fish surveys
  showed the sunfish dominating the community
  biomass, particularly the bluegill sunfish, and
  largemouth bass being the most abundant predator.
• Winterkills between 1976 and 1978 eliminated
  bluegill and bass from the lake
• Shortly after golden shiners a zooplanktivorous
  fish took over as the dominant species in the
  lake.
• A shift in zooplankton assemblage was soon seen,
  from large bodied Daphnia to small bodied
  cladocerans
• In the fall of 1986, 700 large mouthed bass we
  reintroduced into the pond.

9
Methods

• 1. Fish abundance was determined by
• Previous data from studies using mark recapture
  techniques (1951, 1987 and 1988)
• Using mark recapture techniques (1989, 1991 and
  1993) by researches

• 2. Zooplankton abundance was estimated by
• taking 3 vertical hauls from the deepest part of
  the lake
• Sampling at least once a month from early April
  or May until October from 1984- 1993

10
Fish Populations Over Time

• Stocking of bass showed
• A rapid increase in bass density
• Fast decline of other species
• Elimination of golden shiners by 1993

11
Zooplankton Response to Fish Community Structure

• Prior to winterkills
• Daphnia pulicaria and Daphnia galeata mendotae
  dominated the zooplankton community but would
  diminish in numbers in July
• Other cladocerans were rare
• Small cladocerans were essentially absent
• After winterkills and increased golden shiners
• Daphnia pulicaria and Daphnia galeata mendotae
  disappeared
• Other cladocerans and small claocerans took their
  place.
• After bass introduction
• Steady return to former state
• Slowly small species were limited to certain
  parts of the year and eventually disappeared
• Daphnia pulicaria reappeared in the fall of 1991
• Daphnia galeata mendotae reappeared in 1992.
• Daphnia pulicaria and Daphnia galeata mendotae
  remained throughout the summer and fall of 1992

12

• Reintroduction of bass and the subsequent decline
  in planktivorous fish caused
• A10 fold increase in cladoceran biomass
• More than a 2 fold increase in average
  cladoceran body size
• This was caused by
• The replacement of smaller species by the larger
  ones
• An average increase in size within a species
• Copepods showed only a small increase in size and
  no increase in biomass over time.
• Water quality was found to improve dramatically
  with increased daphnia biomass

13
General Conclusions and Implications

• The changes in species composition within the
  lake was predicted by cascading trophic
  relationships and size-selective predation
• Trophic cascading is supported by
• Dramatic increase in zooplankton biomass and
  body length with increased predation on
  plankivores fish by the bass
• Increases in water quality is associated with
  decreased phytoplankton by increased zooplankton.

• The lake exhibited high resilience with its
  return to almost its initial state after the
  disruption of the lack of bass was rectified.
• However there were some small difference which we
  attributed to the lack of bluegill
• No decrease in Daphnia during midsummer

14
Resistance and Resilience of Alpine Lake Fauna to
Fish IntroductionsRoland A. Kapp Kathleen R.
Matthews and Orlando Sarnelle

• Goal
• To report the responses of amphibians, benthic
  macro-invertebrates and zooplankton to fish
  introduction and later fish disappearance on a
  large coarse scale
• Study Area
• In the Sierra Nevada of eastern California and
  contained parts of the Inyo and Sierra National
  Forests, as well as, Kings Canyon Nation Park
• Studies between 1995 and 1997
• Included 533 lakes over 0.5 ha in size and
  usually under 10 ha
• All the lakes where
• At 2800m or higher
• Naturally fishless
• Generally Oligotrophic
• Cold
• Ice free for 4 months of the year

15
Between 1900 and 1960 about 60 of these lakes
were stocked with trout to create recreational
fisheries
Rainbow trout (Oncorhynchus mykiss)
Golden trout (Oncorhynchus mykiss
Brown trout, (Salmo trutta)
Brook trout (Salvelinus fontinalis)
Stocking stopped in 1977 in some of the lakes
found within park boundaries, and some of the
resident populations have died off
16
Methods

• 1. Lakes were divided into 3 categories
• Never Stocked
• Stocked-now fishless (subdivided into 5-10,
  11-20 and gt20 year categories)
• Stocked-fish-present (either through further
  stocking or natural reproduction)
• Visual surveys and gill nets were used to verify
  presence and absence

• 2. Visual Counts of larval and adult amphibians
  preformed and s/m of shoreline calculated
• Mountain yellow-legged frogs (Rana muscosa) were
  the only common amphibian species in the area

17

• 3. Benthic macro-inverts where collected from a
  subset of the lakes by
• 15 - 1m sweeps in each direction of the littoral
  zone.

• 4. Zooplankton was collected for all of the lakes
  by
• 3 vertical tows from the deepest part of the lake

5. Comparisons then done between lake category
amphibian, benthic macro-invertebrates, and
zooplankton abundance and occurrence.
18
Mountain Yellow-legged Frog Response to Stocking
History

• Significant difference in occurrence and
  abundance between never stocked lakes and
  fish-present lakes.
• Overall no significant difference in occurrence
  and abundance between never stocked lakes and
  now- fishless lakes.
• Amount of time fishless has an effect on
  occurrence and abundance of frogs
• 5-10 years fishless 0 of lakes had frogs
• 11-20 years 20 of lakes had frogs
• gt20 years 28 had frogs

19
Benthic Macro-invertebrate Response to Stocking
History

• Expected
• Majority of clinger/swimmer taxa decreased
  significantly in occurrence in fish-present lakes
  compared to never stocked lakes.
• Particularly the larger sized taxa
• Borrowing and distasteful taxa were
  relatively unaffected by the presence of fish.
• Oligochaeta increased in abundance with
  fish-presence
• No significant difference in any of the
  micro-invertebrates in never stock lakes and
  fish-absent lakes
• Unexpected
• Increase of mosquito larva (culux).
• Possibly due to elimination of invertebrate
  predators by fish
• Limnephilus was not significantly reduced in
  occurrence and abundance like the other 4
  caddisfly families.
• Possibly due to differences in what they used to
  make their cases.

20
Zooplankton Occurrence Response to Stocking
History

• 6 crustacean species were common throughout the
  lakes
• The 2 largest were found to be much less often
  in fish-present lakes then in never stocked lakes
• The other 4 were found similar proportions
• 5 common rotifers were found
• 3 were of similar occurrence in fish-present
  lakes and never stocked lakes
• 2 were more common in the fish-present lakes the
  un-stocked lakes and only one of those was more
  then marginally significant
• For both crustaceans and rotifers there was no
  significant different in occurrence between never
  stocked lakes and fishless lakes.

21
Zooplankton Abundance Response to Stocking History

• The 2 larger taxa and 3 of the smaller taxa of
  crustaceans showed similar patterns of abundance
  as occurrence
• Cyclopoda was much more abundant in the
  fish-present lakes then the never stocked lakes
• 3 species of rotifers much more common in the
  fish-present lakes then the never stocked lakes.
• The remaining two were not significant different
  between fish-present and never stocked lakes
• Again there was no statistical difference between
  never stocked lakes and fish-absent lakes.

22
General Conclusions and Implications

• None of the faunal types were able to
  significantly resist introduction of trout
• Given enough time all of the faunal types seemed
  to be able to recover
• Benthic and zooplankton had their greatest
  recovery rate in 5-20 years
• Mountain yellow-legged frogs took much longer to
  recover

• Since the mandate of National parks and national
  forest wilderness areas is to protect natural
  process, the discontinued stocking has helped to
  allow the fauna to recover.
• This positive feedback argues for stronger fish
  removal from the other lakes.
• Mountain yellow-legged frog are of declining
  status, and thus the removal of trout may help to
  alleviate this.
• Their long recovery time suggests the sooner
  this is done the better, as does the decreasing
  viability of the zooplankton egg bank with time.

23
General Conclusions

• Generally lakes are not very resistant to fish
  introduction, but common species are strongly
  resilient
• Disturbances cause sweeping changes throughout
  the community that may be detrimental, overall
  particularly to endangered species.
• In national parks the focus is to maintain
  biodiversity and minimize unnatural disruption,
  removal of exotic species and other disruptions
  would be important to maintain the natural
  biodiversity.
• The suggestion of fast removal of the
  disturbances may be very important for sensitive
  species, such as amphibians.
• Changing in community structure can also be used
  to our advantage in certain areas.
• Increased water clarity is associated with
  increased large daphnia.
• Thus in areas with water quality issues it may be
  beneficial to introduce fish which prey upon
  zooplanktivorous fish.