Response of Fish Assemblages to Changing Acid-base Chemistry in Adirondack Long Term Monitoring Lakes, 1984-2012

The New York State Department of Environmental Conservation (NYSDEC) and Adirondack Lakes Survey Corporation (ALSC) repeatedly surveyed fish assemblages and characterized water chemistry from 44 to 52 lakes during the periods 1984-1987 and 1994-2005, and 2008-2012 to document the regional effects of acidic deposition and potential recovery associated with the 1990 Clean Air Act Amendment (CAAA) under the Adirondack Long-Term Monitoring (ATLM) Project. An initial analysis of changes in fish assemblages between the periods 1984-1987 and 1994-2005 noted modest and mixed recoveries, identified five fish-community response/recovery classes, and helped to devise a fish-community index based on species acid sensitivities (Roy and Bulger 2011). An in-depth analysis of the temporal changes in fish assemblages over the three periods, however, has not been completed, and is needed to determine if, and how, lake ecosystems are recovering due to decreased surface-water acidity (and reduced acidic deposition). Moreover, wide ranges in acid-base chemistry (e.g., pH, acid-neutralizing capacity or ANC, base-cation-surplus or BCS, dissolved organic carbon or DOC, Ca, and inorganic Al), fishery impacts, and recovery responses can provide key data needed to generate and test field-based, fish-chemistry response models. Both issues are identified as priority questions in the Ecological Effects of Deposition of Sulfur, Nitrogen, and Mercury section of the most recent New York State Energy Research and Development Authority’s Environmental Research Program Plan (NYSERDA 2013). In addition, such field-based models could help inform the U.S. Environmental Protection Agency, (USEPA’s) next review of the Secondary National Ambient Air Quality Standards (NAAQS) for the Effects of Sulfur Oxides (SOx) and Nitrogen Oxides (NOx) on Ecosystems. 

 

The main objective of this investigation is to determine if implementation of the 1990 CAAA has significantly improved impaired fish assemblages from acidified lakes of the Adirondack Region between 1984 and 2012. Related goals are to: (a) quantify or qualify the level of recovery (in terms of lake numbers or species’ populations), (b) generate and (or) refine existing fish-chemistry response models, and (c) determine how different management practices (e.g., liming, reclamation, stocking) and lake class or type (e.g., till, seepage) may have affected the recovery of fish communities or selected species populations (e.g., brook trout) that may be associated with improved acid-base chemistry in ALTM lakes. 

 

The U.S. Geological Survey and NYSDEC will assess available fishery data from the set of ALTM lakes repeatedly sampled over the past 28 years primarily to refine or devise new chemistry-fish response models and to test hypotheses that temporal changes have occurred in lake-fish assemblages from all lakes and/or from lakes stratified by acid-base chemistry and lake-type (e.g., thin till, seepage, etc.) according to Driscoll (2011). Specifically, changes in fish population and community metrics will be compared to changes in acid-base chemistry (e.g., pH, ANC, BCS, DOC, Ca, inorganic Al) from about 45 (or more) lakes before the CAAA took effect (1984-87), shortly after implementation (1994-2005), and about 20 years post implementation (2008-2012). At a minimum, the univariate and multivariate analyses proposed below will be utilized to assess temporal trends and hypotheses; they may be amended or change in response to unexpected results (relations or trends).

 

1.Basic summary statistics will be compiled and used to test the null hypothesis (using ANOVA and/or ANCOVA)that (a) selected chemical parameters and (b) key fish population and community metrics (richness, catch-per-unit-effort or CPUE, presence/absence), have not changed significantly at repeatedly sampled sites over time (years) or over the three survey periods. In addition, the net changes, and the significance of changes in selected population and community metrics, likely caused by shifts in acid-base chemistry of ALTM lakes after the 1990 CAAA, will be estimated using Before-After Control-Impact (BACI) analyses (Stewart-Oaten et al. 1986; Underwood 1992). The BACI analyses essentially quantify net changes in respective metrics by adjusting or correcting observed responses to changes in the same metrics at unaltered reference (control) reaches. Fish assemblages from lakes with little change in acid-base chemistry (e.g., pH and ANC) will act as controls and be used to determine the magnitude and significance of net changes in key fishery metrics from lakes where acid-base chemistry improved slightly, moderately, or greatly following the CAAA.

 

2.An in-depth analysis of temporal changes in fish community composition will also be done using nonmetricmultidimensional scaling (MDS) ordination of fish presence/absence or relative abundance (e.g., richness and CPUE) data (Kruskal 1964; Shepard 1962). An Analysis of Similarities (ANOSIM) (Clarke and Warwick 2001) will be used to test the null hypothesis that species assemblages do not differ significantly across the three sampling periods. These analyses will also be used to assess the effects of lake type and other confounding factors (e.g., stocking, invasive species, liming) on the recovery of fish assemblages (e.g., richness, CPUE) in lakes with slight, moderate, and large improvements in acid-base chemistry.

 

3.Where significant differences are identified between fish assemblages from different periods or lake types(classes), the fish species most responsible for noted differences will be identified using Similarity Percentage (SIMPER) analysis (Clarke and Warwick 2001).

 

4.The acid-base constituents (e.g., pH, ANC, DOC, Ca, BCS, inorganic Al) that potentially regulate the distributionand abundance of key (or indicator) fish species (and entire assemblages) will be identified and important relations will be quantified using distance-based linear models (DISTLM) (Anderson et al. 2008).

 

Aside from quantifying changes in fish assemblages in ALTM lakes over time, the collective results may help define (or refine) chemistry-fish response models, evaluate or validate the fish-community index presented by Roy and Bulger (2011), and conceivably ascertain chemistry thresholds that limit the occurrence of selected indicator species or species groups in lakes of different acidity classes. Proposed analyses should also help demonstrate the value of the original (baseline) fisheries dataset, the importance of both resurveys, and identify strategies to more effectively monitor long-term changes in fish assemblages from the original ALTM lakes or other lakes of the region.

 

Results will be disseminated at relevant regional and national scientific conferences (as opportune) and summarized in a peer-reviewed journal publication. In addition, the project will be described on a publicly-accessible web page that includes a printable project-summary handout.

 

Driscoll, C. 2011. The road to recovery of Adirondack lakes from 

acidic deposition: are we there yet? Gordon Research 

Conference: Sentinels of Global Change, July 10-15, 2011, Bates 

College, Lewiston, ME 

 

NYSERDA. 2013. NYSERDA Environmental Research Program 

Plan, Research Area 1: Ecological Effects of Deposition of 

Sulfur, Nitrogen, and Mercury. 34 pp., New York State Energy 

Research and Development Authority, Albany, NY.      

 

Roy, K.M., and A.J. Bulger. 2011. Fish community changes and 

mercury in Adirondack long-term monitoring lakes. 

Environmental Monitoring, Evaluation, and Protection in New 

York: Linking Science and Policy. NYSERDA, November 15-16, 

2011, Albany, NY.