LMVJV Waterfowl Working Group

LMVJV Waterfowl Working Group

Report to the Management Board – June 2007

During the past year, the LMVJV Waterfowl Working Group (Working Group) focused the vast majority of its time and energy as a group on completing the refinement of the MAV’s waterfowl foraging habitat objectives. The last meeting of the full Working Group was held on June 27-28, 2006. The purpose of this meeting was to reevaluate a series of biological assumptions previously identified in the March 2006 meeting and to review progress toward updating the public lands water management unit and sanctuary databases. Subsequent ad hoc meetings were held on September 7 and September 11. Additionally, several meetings involving the Co-chairs, the GIS Biologist, and others occurred in the process of allocating MAV foraging objectives.

As a reminder, the following list of biological assumptions were evaluated and resolved:

Population Objectives:

• Revision to the MAV population target to address ducks wintering in Mexico.
• Decision NOT to incorporate migration chronology into the derivation of MAV population targets.

Habitat Objectives:

• Revision to the MAV DED derivation model to account for species-specific variation in body size.
• Revision of the DED foraging habitat capacity table. (Table 1).
• Revision to the MAV DED derivation model to address inter-specific competition, i.e. snow geese.
• Revision to the MAV DED derivation model regarding the allocation of wood duck foraging objectives to natural flooded forest habitats vs. moist-soil/agricultural habitats.

The original habitat objectives did not account for early migrating waterfowl and by including them in the derivation makes those goals more realistic. Although it does remove a level of conservatism in the model, the Working Group decided to account for early migrating waterfowl by using mid-winter inventory data sets for Mexico to derive new population targets. This resulted in a reduction of DEDs for all states except Missouri, which increased slightly.

Migration chronology was heavily debated and the Working Group feels it should be investigated further into derivation of population targets, however there is insufficient information presented as to how this should be addressed. The consensus was to maintain the existing status of a 110-day wintering period, but acknowledge that migration chronology and the temporal availability of habitat exists.

DEDs represent the number of ducks that can obtain daily energy requirements from an acre of foraging habitat for a day. Foraging objectives have been based on the energy requirements of mallards due to extensive knowledge on that species. The Working Group recognizes that not all waterfowl are the size of a mallard and agreed that a new estimate should be used to account for species-specific variation in body size. A recent analysis determined the daily energy requirements of ducks wintering in the LMVJV. This analysis was based on the average body mass and proportional abundance of dabbling ducks and wood ducks in population goals of the LMVJV rather than exclusively on the energy requirements of mallards. The previously assumed daily energy requirement of a mallard was 292 kcal and the new estimate of an “average duck” wintering in the LMV is assumed to be 294.35 kcal. Since this value is more representative of most ducks wintering in the LMV, the Working Group agreed to adopt the new daily energy requirement and included it in the DED derivation model. Diving ducks were omitted because the NAWMP focuses on dabbling ducks and it is assumed that diving ducks are being provided with enough suitable habitat.

Carrying capacity estimates of foraging habitat were derived using the energy requirements of a mallard size duck (292 kcal) and indicated in Table 5 of the Joint Venture Evaluation Plan. With the adoption of an energetic value (294.35 kcal) representing an averaged sized duck, this table was updated to reflect the change (Table 1). This table is important in determining accomplishments of the LMVJV toward meeting habitat goals of the NAWMP.

The DED derivation model was also revised to account for inter-specific competition with a goal to determine the impacts of competition for habitat between geese, divers and dabbling ducks. To account for the competition between geese (Canadas, Snows, and White-fronts) and dabbling ducks, a goose population objective must be established and a conversion factor to determine goose use day habitat needs. To create the goose population objective, a 10-year average goose population estimate was used from the Mississippi Flyway midwinter inventory surveys. Based on a recent analysis, the group assumes that the average goose had a foraging need 1.4 times of the average utilized duck foraging habitats 25% of the time during the 110-day wintering period. Because diving ducks utilize a very small portion of dabbling duck habitat and should be accounted for by the conservatism already incorporated into the plan, diving ducks were not considered to be a factor. Also, allocating 25% of goose use days to floodable habitat, a high proportion, will give an added habitat buffer for diver, dabbler competition. The Working Group agreed to use this methodology and the results for each state were computed and presented (Table 2).

Table 1: Carrying capacity of selected foraging habitats (expressed as duck energy-days/ac [DEDs/ac]) for a hypothetical average dabbling duck (actually 7 species of dabbling ducks plus the wood duck) representing the proportional abundance of these species in the population goals of the Lower Mississippi Valley Joint Venture. For simplicity, we rounded estimates of food available and DEDs/ac to the nearest whole number but calculated all estimates using the most accurate data available.

Habitat / Food available (kg/ha) / True metabolizable energy (TME;kcal/g) / DEDs/ac
Moist-soil / 600 / 2.47 / 1,868
Harvested Crops1
Rice / 80 / 3.34 / 138
Soybean / 60 / 2.65 / 36
Corn / 150 / 3.67 / 505
Milo / 150 / 3.49 / 480
Unharvested Crops
Rice / 5,240 / 3.34 / 23,833
Soybean / 1,334 / 2.65 / 4,677
Milo / 3,811 / 3.49 / 18,046
Corn / 5,716 / 3.67 / 28,591
Japanese millet / 1,500 / 2.61 / 5,203
Bottomland Hardwoods2
30% red oak / 79 / 2.76 / 109
40% red oak / 91 / 2.76 / 156
50% red oak / 104 / 2.76 / 203
60% red oak / 116 / 2.76 / 250
70% red oak / 128 / 2.76 / 297
80% red oak / 141 / 2.76 / 345
90% red oak / 153 / 2.76 / 392
100% red oak / 166 / 2.76 / 439

1 An ad hoc energetics value for harvested millet was set at 90 DEDs/ac, which is 5% of the unharvested value.

2 An ad hoc energetics value of 38 DEDs/ac was set for all hardwood habitats that had less than 30% red oak component.

Table 2: Allocation of DEDs accounting for competition from geese on waterfowl foraging habitat objectives for the LMV.

State / Competitive DED Allocation
AR / 14,463,130
LA / 15,788,960
MS / 2,120,140
TN / 816,750
KY / 2,312,640
MO / 6,397,710
MAV / 41,899,330

Previous assumptions related to wood duck foraging requirements were that wood ducks met their needs entirely in naturally flooded habitats. The Working Group acknowledged that wood ducks utilize not only naturally flooded areas, but managed forested wetlands, moist-soil and agricultural lands as well. In order to determine what proportion of wood duck foraging habitat objectives should be allocated to flooded timber habitats, further literature review was required and it was determined the allocation of 75% forested wetlands and 25% moist-soil is appropriate.

All of the above factors resulted in the DED objectives provided in the following table:

Table 3: Revised MAV Duck Energy Days Objectives – May 2007

State / Dabblers / Wood Ducks / Goose / Total
AR / 169,512,307 / 35,451,900 / 14,463,130 / 219,427,337
KY / 1,658,103 / 738,100 / 2,312,640 / 4,708,843
LA / 64,021,730 / 41,102,600 / 15,788,960 / 120,913,290
MO / 8,765,105 / 2,862,200 / 6,397,710 / 18,025,015
MS / 50,801,637 / 19,715,300 / 2,120,140 / 72,637,077
TN / 28,903,908 / 3,905,000 / 816,750 / 33,625,658
MAV / 323,662,790 / 103,775,100 / 41,899,330 / 469,337,220

In addition to addressing the above list of biological issues, the Working Group developed a framework for defining and characterizing sanctuary applicable to inventory private and public lands. This inventory process presents several challenges. Much of this challenge relates to the fact that sanctuary throughout the LMV region can be described as having various degrees of protection for wintering and migratory waterfowl. For the purpose of this inventory, various degrees of protection should be described based upon the percentage of time in which protection from human disturbance occurs throughout the 110 day wintering period (mid November through February).

Categories should include: Full Protection Sanctuaries – designated sanctuaries on either public or private lands which offer full protection from all human disturbance during the described wintering period; Partial Protection Sanctuaries – those sanctuaries which offer some degree of protection by designating a time frame structure that partially limits human disturbance on a given area; Non-designated Sanctuaries – sanctuaries which offer no designated protection yet are highly sought out and utilized by waterfowl since they offer at least some degree of protection, due in part to the size of the area, the unique location, or inaccessibility as it relates to human disturbance; Temporary Sanctuaries – sanctuaries which are not permanently designated to provide protection from human disturbance with restrictions that might vary within the designated 110 day wintering period or from year to year.

During the past 12 months, an inventory of these various sanctuary types occurring in the LMV was begun, but was put on hold temporarily due the more pressing need to complete the Water Management Unit database update. A complete analysis of the availability and functionality of sanctuary is recognized as an important task going forward. This analysis should not only consider the degree of sanctuary, as listed above, but also should identify other factors related to the protection provided to waterfowl, such as minimum size and foraging availability.

Although the Working Group did finalize the biological assumptions during the June meeting, it failed to reach a consensus on how to allocate DEDs within the MAV, by state, across the waterfowl foraging habitat matrix. The primary reason that the June meeting bogged down was twofold. First, the interactive allocation process designed for the meeting was not sufficiently structured with “decision rules” for individuals to objectively evaluate the wealth of available information. That is, partners were provided with multiple spreadsheets of population targets, revised DED values by habitat types, body-sized specific energy demands proportional to species abundance in the MAV, public and private management capability by state, and observed winter waterfowl habitats for public and private management as well as natural flooding by state – yet there were no obvious mechanisms for synthesizing the vast quantity of information to inform decisions. Second, there remained a level of discomfort for making decisions due to the lack of an explicit means to address uncertainties inherent in biological planning with imperfect knowledge.

An ad hoc meeting was held by members of the Working Group on September 7, 2006 to explore options for getting back on track by reviewing the June meeting’s progress and pile-up, considering alternative allocation processes, and seeking opportunities to characterize and incorporate uncertainties in the process. The group developed a potential set of decision-rules to guide the allocation process (Appendix A). It was recognized that establishing foraging habitat objectives is an iterative process that results are subject to constant refinement as new data becomes available, and that comprehensive reviews should occur at least every 5 years. Additionally, there was an awareness by the Working Group that each decision point would be based on a number of assumptions and that those assumptions should be explicitly documented and prioritized to focus evaluation.

Subsequent to the meeting, the group identified 4 priority tasks that needed attention in preparation for reconvening the Working Group:

(1)Explicitly document the allocation process decision rules and assumptions to be circulated prior to the next Working Group meeting.

(2)Upgrade the allocation matrix to recognize state and federal management categories, and to split out unharvested and harvested crops.

(3)Calculate existing winter waterfowl habitat capability on state and federal lands based on the 2006 Water Management Unit inventory results.

(4)Generate a list of conservation design “inputs” that includes the set of information necessary to inform decisions at each rule.

The decision rules were promptly developed and disseminated to the Working Group for their comment and approval. In addition, the allocation matrix was updated, as described in (2) above. One vitally important ingredient needed to continue the allocation process, however, was delayed by several months, namely the Water Management Unit update. It was not until March of this year that adequate information was provided to allow these calculations to be made.

In short, the LMVJV goal is to winter 4.27 million ducks for 110 days which translates to a DED target of 469,337,220. The six states within the LMVJV are committed to providing these habitat objectives through a combination of public managed land, privately managed land and those habitats that flood naturally. Using the revised biological assumptions and with guidance from the Decision Rules, the Working Group derived new waterfowl foraging objectives for each state in the LMVJV summarized in Table 4. A detailed allocation for each state can be found in Appendix B.

Table 4: Summary of new DED allocation by state indicating surplus or deficit.

State / DED Target / Naturally Flooded / Managed Habitat / Public Managed / Private Managed
AR / 219,427,337 / 87,770,935 / 131,656,402 / 74,749,402 / 56,907,000
KY / 4,708,843 / 1,412,653 / 3,296,190 / 2,636,952 / 659,238
LA / 120,913,290 / 48,365,328 / 72,547,974 / 47,837,399 / 24,710,575
MO / 18,025,015 / 5,407,512 / 12,617,510 / 10,724,884 / 1,892,628
MS / 72,637,077 / 21,792,771 / 50,845,954 / 25,422,977 / 25,422,977
TN / 33,625,658 / 10,087,704 / 23,537,961 / 21,184,165 / 2,353,796
MAV Total / 469,337,220 / 174,836,903 / 294,501,991 / 182,555,779 / 111,946,214

One topic of recurrence at Working Group meetings is how to account for unharvested crops on privately owned lands managed outside of a conservation program. Most of these lands are duck clubs that plant a crop such as rice, soybeans, corn or millet. Currently the Working Group acknowledges that these crops exist however there are several issues associated with these types of crops and how to account for them. The primary concern is these crops are ephemeral in nature and many may not exist from one year to the next. Since the allocation of habitat objectives are revisited every five years, a significant amount of variation can occur from one year to the next, leaving the Working Group to account for this with great caution. Some commercial duck clubs may be considered as a somewhat reliable source of habitat, however smaller commercial operations or those private clubs that are for personal recreation only need to be regarded cautiously because budgets may very from year to year, crop prices may dictate if a crop is left standing or not or severe drought may adversely impact these crops. Until a repeatable technique is developed to account for the amount of habitat, quality of habitat and reliability of these crops on an annual basis, these habitat types are regarded as lagniappe.

LMVJV Waterfowl Working Group 12-month Work Plan

The focus of the Working Group over the next year will be directed at three primary tasks:

1. Completion of Foraging Habitat Allocation

1. Upon acceptance of this report and its state-level allocation targets by the Management Board, a series of meetings should be held to step down these allocations by WMA/NWR within each state by September 30, 2007.
2. The DED allocation for the West Gulf Coastal Plain should be revised, using the revised Foraging Capacity Table by November 30, 2007.

3.The Working Group should continue to address the biological underpinnings of the assumptions and uncertainties associated with waterfowl foraging habitat allocations, e.g. extent and availability of unharvested crops on private lands, level of inter-specific competition for foraging habitats, affects of species variation in migration chronology, etc.

B. Begin Addressing the 2005 NAWMP Assessment Recommendations

1. TASK 1 – Review and consider the Assessment Team’s 27 National Joint Venture recommendations. (By January 2008).
2. TASK 2 – Review and consider the Assessment Team’s 8 recommendations specific to the LMVJV. (By January 2008).

C. Continue to Develop Sanctuary and Moist-soil Databases

1.Complete inventory and analysis of sanctuary habitats in the LMV, to include factors such as level of protection, availability of foraging habitats, size, landscape setting, etc. (By November 30, 2007).

2.Ensure that the deployment of the recently-developed Moist-soil Management Database (Waterfowl Habitat Tracking System) is completed. (By August 1, 2007)

Appendix A

Decision Rule Process

1

Decision Rule Process

Decision-rule 1: Establishing foraging habitat objectives is an iterative process. Results are subject to constant refinement as new data becomes available. Comprehensive reviews should occur at ≤5 year intervals.

Decision-rule 2: Approach each decision point on a state by state basis to account for the uniqueness of the ecological systems.

Decision-rule 3: The first objective should be allocated to foraging habitat occurring within the remnant natural ecological system (e.g., habitat provided through natural flooding).

Ideally, Joint Venture partners would have information on DEDs available in the 2-3 yr winter flood events as a basis to “mark” the initial habitat objective. Unfortunately, this data is not yet complete (DU and FWS are making progress towards that end). Thus the decision-rule will be,

3a. Use the observed flood events collected for the MAV-wide Waterfowl Habitat Monitoring Program to identify an appropriate mark. The “top/max-mark” should be derived by a DED quantity where natural flooding exceeded that threshold in 3 of 5 winters of observed flood events.

3b. The top-mark should then be assessed as to how reasonable it would be to achieve by converting the DED to a daily acreage value. If unreasonable, the mark should be lowered. (The current value is 195 DEDs/acre)

3c. Available data in GIS should be consulted to guide this decision.

Decision-rule 4: Allocate a first-iteration mark to public managed habitat. Specifically, habitat provided through management on federal and state lands.

4a. For each state begin with an initial mark equivalent to the existing habitat capacity (adjusted for observed performance) for federal and state lands based on the waterfowl management unit inventory dataset. Performance is the averaged percentage of observed inundation to unit capacity.

Decision-rule 5: Allocate a first-iteration mark to private managed habitat. Specifically, habitat provided through management for private lands managed within a program (MIP) and to private lands not affiliated with a formal conservation program (MOP).