Underplanting response to Amur honeysuckle invasion and deer herbivory in mixed hardwood forests

Transcription

1 Underplanting response to Amur honeysuckle invasion and deer herbivory in mixed hardwood forests Charlotte Freeman Forestry and Natural Resources Purdue University

2 Rooney and Waller 2003; Randhir and Erol 2013; vnrc.org; Limits to Forest Regeneration Climate change Habitat fragmentation Changes in disturbance regimes Invasive species Overabundant wildlife

3 Amur honeysuckle Lonicera maackii Native to China Seed exchanges Introduced in the US in late 1800s Reported as naturalized in 1950s, later invasive Luken and Theiret 1996;

4 Luken and Theiret 1996; Collier et al 2002; Trisel and Gorchov 1994; McEwan et al 2010; Dorning and Cipollini 2006; Hutchinson and Vankat 1997 Amur honeysuckle Shallow roots Extended leaf phenology Allelopathic compounds Competition for nutrients Lower light, litterfall, extended growing season Chemical inhibition Low seedling and herb cover, diversity, and regeneration

5 White-tailed deer Odocoileus virginianus High population densities Browse native herbs and tree seedlings Homogenize landscapes Promote spread of invasive species Shelton et al. 2014; Knight et al. 2009; Rossell et al., 2005; Rooney and Waller 2003; Rooney 2001; Webster et al., 2005; Aronson and Handel 2011; content.time.com

6 Deer Honeysuckle Deer x Honeysuckle Native Herbs -Browse -Suppress -Protection? -Vulnerable? Native Trees -Browse -Suppress -Protection? -Vulnerable? Forest Structure and Composition Deer Honeysuckle -Homogenize -Shift to browse-tolerant -Disperses seeds -Promote spread -Shrub layer -Suppress? -Food source -Protection (?)

7 Deer and Honeysuckle Loomis et al. (2015) Deer sugar maple survival Honeysuckle sugar maple survival

8 How do we manage areas with Remove invasives? Exclude deer? both?

9 How does the presence/absence of Amur honeysuckle and/or deer impact: 1. Naturally-regenerated seedling density 2. Survival and growth of underplanted seedlings

10 Study Sites

11 Previous Work (Dr. Josh Shields) Woody invasive removal By hand! Pre/post removal in native seedling and herb diversity and cover Shields 2013; Shields et al 2014; Shields et al. 2015

12 Treatments

13

14 Cameras

15 Deer

16 How does the presence/absence of Amur honeysuckle and/or deer impact: 1. Naturally-regenerated seedling density

17 Natural Regeneration All woody seedlings identified and counted in quadrats Fall 2013, 2014, 2015

18 Natural Regeneration Species richness and diversity Abundant species/genera divided into groups Density

19 Native Tree Seedlings Richness No differences Diversity No differences Density No differences

20 Honeysuckle present Shadetolerance Deer present Browse preference Honeysuckle and Deer present Acer saccharum sugar maple High - Med - Carya spp. hickory Celtis occidentalis hackberry Fraxinus americana white ash - Low-Med - High - - Med - Low - Med Med - Liriodendron tulipifera tuliptree Prunus serotina black cherry more over time Very low - Med - Very low - Low - Quercus spp. oak - Med - High - Sassafras albidum sassafras Ulmus spp. elms - Very low Other - less outside - Low-Med - Low Med

21 What does this indicate? Increases in unlikely canopyreplacement species White ash Elms Shifts to more shade-tolerant and browse-tolerant species Away from browse-sensitive, shade-intolerant

22 How does the presence/absence of Amur honeysuckle and/or deer impact: 2. Survival and growth of underplanted seedlings

23 Underplanting Restoration tool Increase the abundance of species with low regeneration 1 st stage

24 Northern red oak Quercus rubra Timber and wildlife Consumed by wildlife Preferred species by deer in Indiana

25 American chestnut Castanea dentata Timber and wildlife Decimated by blight in the early 1900s Blight-resistant trees Trying to increase abundance into U.S. forests

26 Underplanted seedlings 1 year-old bareroot American chestnut northern red oak Vegetation control 2 nd cohort Planted Seedling

27 Treatments

28 Measurements Survival Height Plant moisture stress

29 Survival: American chestnut Cohort 1 Cohort 2 No HS, No D HS, No D No HS, No D No HS, D No HS, D HS, D HS, D and HS, No D

30 Why the sharp contrast? Cohort 1 Planted in June Low precipitation following Cohort 2 Planted in April Normal levels of precipitation

31 Survival-northern red oak Cohort 1 Cohort 2 No HS, No D HS, No D No HS, D No HS, No D HS, D HS, No D No HS, D HS, D

32 Survival Greater without HS and deer Why might this be?

33 Height American chestnut northern red oak Same for cohort 1

34 Plant moisture stress American chestnut northern red oak

35 Light

36 How does the presence/absence of Amur honeysuckle and/or deer impact: 2. Survival and growth of underplanted seedlings -Effect: -height -moisture stress -light availability -survival

37 Quick note about native herbs: diversity, richness, and cover No effect of deer

38 Conclusions Removal of honeysuckle Continue to see benefits diversity, richness Exclude deer Effects may take longer than 2 yrs. Interactive effects over time

39 Management Implications Deer and honeysuckle Shifts in composition of nat. regen. Underplanting 1 st step Can have high survival! Manage both!

40 Acknowledgements Jacobs lab Jenkins lab Brian Beheler and Michael Loesch-Fries Brent Pursell Vigo County Park District Dr. Saunders, Dr. Flaherty, Dr. Tim Smyser, and Sally Weeks

41 Questions?