Deer harvest objective for the Deer Plan

Transcription

1 Deer harvest bjective fr the Deer Plan December 12, 2017 Summary and Backgrund fr DMPAC April 2018 NOTE: THIS IS A COPY OF A DOCUMENT DISCUSSED WITH DMPAC IN IT CONTAINS INFORMATION CONSIDERED BY DNR IN THE IDENTIFICATION OF THE DEER PLAN HARVEST TARGET OF 200,000 DEER PER YEAR. SUBSEQUENT DMPAC FEEDBACK WAS ALSO CONSIDERED IN SETTING THE TARGET. Summary In respnse t requests frm a subset f deer management stakehlders, the Minnesta Department f Natural Resurces (DNR) has agreed t develp an annual, statewide harvest bjective fr inclusin in the Deer Management Plan. DNR is interested in develping an bjective that acknwledges annual changes in harvest due t factrs such as winter weather, annual hunting pressure, and deer ppulatin status relative t lcal ppulatin gals. At the Nvember 15, 2017, Deer Management Plan Advisry Cmmittee (DMPAC) meeting, DNR staff prpsed a harvest bjective that we believe will be sustainable ver the lng term: a 5-year rlling average f 190,000 deer. DMPAC members prvided feedback via an nline survey; results indicate that the cmmittee has a diversity f preferences, with sme believing the prpsed recmmendatin was t lw, sme believing it t be t high, sme expressing supprt fr the recmmendatin as is, and sme questining the value f a statewide harvest bjective. Prpsed alternatives included values frm 150,000 t 225,000 deer harvested per year. After cnsidering the range f respnses t the prpsed harvest bjective, and the variety f interests in deer management, DNR has decided t include a prpsed harvest bjective f 190,000 deer per year in the draft Deer Management Plan t be distributed fr brad public cmment in winter/spring A detailed ratinale fr this decisin, alng with the prpsed use f the harvest bjective and backgrund n the discussin, is prvided belw. Use f the harvest bjective DNR will use the annual deer harvest each year as a perfrmance metric. This means that DNR will cmpare the annual harvest t the bjective f 190,000 deer. In general, when annual harvest is less than the bjective f 190,000 it will indicate a need t increase deer ppulatins s higher harvests clser t the target are achievable in the future. Similarly, when annual harvest is greater than 190,000, we will need management t decrease deer ppulatins s harvests in the future will be clser t the target. As an example, annual harvests may exceed 190,000 fr a cuple years in a rw in rder t mve the ppulatin tward the harvest bjective. We anticipate that there will be times when lcal deer permit area (DPA) ppulatin gals and the statewide harvest bjective cnflict with each ther. When cnflicts ccur, DNR will priritize management t meet publiclyestablished DPA ppulatin gals. At the plan s mid-pint, DNR will review all perfrmance measures t assess whether changes are needed.

2 Backgrund Over the last 2+ years, the Minnesta Deer Hunters Assciatin (MDHA), and mre recently sme thers n the Deer Management Plan Advisry Cmmittee (DMPAC), expressed a desire fr the Minnesta Department f Natural Resurces (DNR) t establish an annual harvest bjective fr deer. The DNR Cmmissiner agreed t include a harvest bjective in the statewide deer management plan that is being develped. DNR s ratinale Determinatin f the harvest bjective The draft deer management plan will include a DNR-recmmended harvest bjective f 190,000 deer/year. That is the harvest level we can reasnably expect when deer ppulatins in DPAs are within publiclyestablished ppulatin gals. Annual harvest averaged 191,000 fr the years 1990 & when the statewide ppulatin was at a desired level and harvest was regulated t generally maintain stable ppulatins (see graph belw). During 2017, deer ppulatins n average statewide appear clse t gal (i.e., ½ f permit areas are at gal, ¼ are belw gal, & ¼ are abve gal), the mdel-based predictin is a harvest f 195, ,000 deer, and registered harvest is n that pace. The DNR ppulatin mdel is nt suitable fr frecasting lng-term sustainable harvest fr 2 main reasns: When deer densities becme high in an area, deer tend t mve away (emigrate) and/r shw lwer survival r reprductive rates (e.g., when fd r cver becmes limiting). The mdel is nt designed t frecast beynd ne year and des nt have density-dependent feedback that wuld accurately frecast these changes. Althugh the mdel includes the effects f the bserved winter severity index int predictins abut ppulatin grwth and harvest fr the fllwing year, it wuld be misleading t prject the sustainable harvest fr a DPA at gal based n average winter severity. Because substantial harvest reductins ccur fllwing intermittent severe winters (every 5-10 years), harvest prjectins based n average winter severity wuld result in an verestimate f sustainable harvest. In the future, we anticipate that the annual harvest will vary between 140,000 and 240,000 deer/year (see pen circles and light blue band in graph belw). Fr backgrund, Our analysis purpsely excluded deer harvest prir t 1990, recgnizing thse levels wuld nt adequately meet recreatinal hunting desires. After pairs f severe winters in and the average annual harvest was ~140,000. Since 1990, harvests belw 170,000 were experienced when DNR intended t increase the deer ppulatin.

3 Harvest f 244,000 in 1992 was required t reduce the deer ppulatin after a recent lack f severe winters and 2 decades under a seasn structure designed t increase the ppulatin. Harvests f 212, ,000 during were nt aggressive enugh, given an unprecedented three cnsecutive very mild winters (i.e., ). Extremely aggressive harvests f 256, ,000 during are very unlikely t be needed r pssible in the future. Harvest rates at that time were specifically designed t reduce deer ppulatins and were never intended t be sustained ver the lng-term. Deer densities during that time exceeded scial carrying capacity and ptentially eclgical carrying capacity. The enhanced management tls initiated in 2003 (e.g., ver the cunter either-sex licenses; Managed, Intensive, and Early Antlerless designatins) enable DNR t prevent deer densities frm reaching thse levels again. DMPAC respnse t DNR prpsal The DNR s recmmended harvest bjective f 190,000 deer/year was discussed with the DMPAC at the Nvember 2017 meeting. Subsequently, DNR surveyed the DMPAC members abut their reactins t the recmmendatin. All 19 DMPAC members respnded t the survey. Rughly 1/3 f the cmmittee expressed cncern abut a harvest bjective and its influence n DNR management f deer (e.g., ptentially being in

4 cnflict with managing fr deer ppulatin gals), rughly 1/3 cmmunicated supprt fr the DNR prpsal r a lwer level, and rughly 1/3 ppsed the Sectin recmmendatin (i.e. desiring a higher harvest bjective). Minnesta Deer Hunters Assciatin (MDHA) Standing Reslutin The MDHA publicly annunced a standing reslutin frm 2014 calling fr a harvest bjective f 225,000 deer/year (Engwall, Star Tribune, February 2015; persnal cmmunicatin t the DMPAC n Nv. 17, 2017). The MDHA cntinues t prefer that level f harvest, and ther rganized deer hunting grups n DMPAC have agreed. Ratinale and histrical cntext The stated ratinale was that the average harvest during was 220,000 deer/year (black hrizntal line in graph belw). Annual harvest was at least 225,000 deer (red line) nly in 1992 and , all years in which deer densities were generally agreed t be t high, and regulatins were set t achieve harvests that wuld significantly reduce deer densities.

5 Deer harvest related t deer densities (see als the table at the end f this dcument) The DNR and mst stakehlders are unlikely t supprt deer densities as high as they were during Deer ppulatins acrss mst permit areas were abve established gals. Representatives n gal-setting cmmittees and the brad interests they represented (e.g., deer hunters, frest managers, farmers, cnservatin rganizatins) expressed agreement with DNR Wildlife that deer densities were far t high. The deer ppulatin gal setting prcess during clearly shwed brad public desire t lwer deer densities frm thse ccurring during that time. The seasn structure was revised t aggressively increase antlerless harvest and reduce deer densities. Example ranges f acceptability fr deer harvest, given deer densities needed t supprt harvest The DNR harvest bjective (blue line in graph belw) accunts fr stakehlders wh want relatively lw deer densities as well as stakehlders wh want relatively high deer densities. The MDHA prpsed harvest target (red line) des nt adequately accunt fr the interest f ther stakehlders and it is nt sustainable because harvest at that level reduces deer densities.

6 Deer harvest related t deer densities (cntinued frm abve) Deer harvest Label Example years Deer densities Management cntext Less than 100,000 Unacceptably lw Befre 1983 Wide fluctuatins Antlerless harvest nt well regulated. Seasn clsures nt uncmmn. 140,000 Lwest anticipated Steadily increasing (with mderate t severe winter cnditins) Regulatry emphasis t avid verharvests f antlerless deer. Severe winters in the early-1980s limited excessive ppulatin grwth. 140,000 Lwest anticipated 1997 & 2014 Rapidly increasing (with mild winter cnditins) Back-t-back severe winters reduced deer densities significantly belw desired levels, s we restricted harvest t allw the densities t increase. 190,000 DNR target 1990 & Maintenance f densities near gal levels Management fcus shifted; recgnitin f greater need fr antlerless harvest t cntrl the ppulatin. 220,000 Near MDHA prpsal f 225,000 Average during Steadily decreasing This harvest level can ccur fr a few years but is nt sustainable because it reduces deer densities ver time. Harvests f this level nly ccurred twice prir t ,000 Highest anticipated 1992 Rapidly decreasing This harvest level may be needed rarely t quickly reduce deer densities. When used in 1992, deer densities were t high but still nt high enugh t prevent this harvest frm rapidly reducing the ppulatin. Mre than 245,000 Unacceptably high Rapidly decreasing Harvests this high were used nly temprarily t reduce unprecedented deer densities.