Kia Kiawa wah h Is Isla land nd Bo Bobca bcats: ts: A Ke - - PowerPoint PPT Presentation

Kia Kiawa wah h Is Isla land nd Bo Bobca bcats: ts:

A Ke Keystone tone Species cies in in a De Develo loping ping Landsca dscape pe

Shane Roberts The Mystery an and Mag agic of f Bobcats March 26, , 2019

Pe People, ple, De Deer, r, & & Pr Predators dators

Pe People, ple, De Deer, r, & & Pr Predators dators

Pe People, ple, De Deer, r, & & Pr Predators dators

Pe People, ple, De Deer, r, & & Pr Predators dators

• Miss. State Univ.

1970

Re Resid sidential ential De Devel velopment

• pment

1975 1980 1985 1990 1995 2000 2005

Red = Developed

1970

Re Resid sidential ential De Devel velopment

• pment

1975 1980 1985 1990 1995 2000 2005

Red = Developed

Bo Bobc bcat at & De Deer r Re Rese searc arch h on K n Kia iawah wah

1996-1997

• Dense but healthy

deer population

• Dense bobcat

population (≈30)

• Bobcats eat mostly

rodents (>40%), some deer

Bo Bobc bcat at & De Deer r Re Rese searc arch h on K n Kia iawah wah

2000-2001

• Relatively stable

bobcat population

• Similar diet
• Bigger home

ranges and higher mortality on west end vs east end

Bo Bobc bcat at & De Deer r Re Rese searc arch h on K n Kia iawah wah

2002-2003

• Objectives

– Deer survival rates and causes of mortality? – Differences between east and west ends?

• Collared 30 does each year

– Radio-collar, eartag, VIT

• Neonatal fawns

– Expandable radio-collar – Monitored year round

De Deer er Mo Monitoring nitoring

De Deer r Faw awn n Sur urvi vival val

• 61 fawns monitored during 2002 & 2003
• 51 mortalities (16% survival)

– 31 bobcat (61%) – 8 vehicle – 5 alligator – 7 other

• Moderately sensitive to habitat

fragmentation

• Typically avoid interactions with humans
• Not usually a major deer predator!

Bo Bobc bcat at (L (Lynx nx ru rufu fus)

Bo Bobc bcat at & De Deer r Re Rese searc arch h on K n Kia iawah wah

2004-2005

• Objectives

– Deer survival and causes of mortality – Bobcats ecology – Bobcat habitat suitability

• Collared 16 bobcats

– Home range size & overlap – Reproduction & survival – Habitat use & movements – Interactions with deer

Bo Bobc bcat at Mo Monitoring nitoring

De Deer r Faw awn n Sur urvi vival val

• 134 fawns radio-

collared

• 105 mortalities

– 70 bobcat (67%)

• Bobcat predation

– 66% within 2 weeks – 97% within 5 weeks

De Deer r Faw awn n Sur urvi vival val

• Yearly variation

– Individual bobcat prey selection

• #795 at 35% (8) in 2002

20 40 60 80 100 2002 2003 2004 2005 2-week Survival from Bobcat (%)

De Deer r Faw awn n Sur urvi vival val

• Yearly variation

– Diet optimization – Rodent abundance

20 40 60 80 100 2002 2003 2004 2005 2-week Survival from Bobcat (%)

More concentrated fawning habitat = higher chance of bobcat predation

Hab abit itat at & & Bo Bobcat bcat Pre Predation dation

Bo Bobcat bcat Re Reprod production uction

• 6 dens located

– 1.8 kittens/den (range = 1-3) – >5 acre patches of forest or shrub

Bo Bobc bcat at Home me Ra Rang nges es

• Males had larger home ranges than females
• Juvenile females had larger home ranges than

adult females

• Adult females on the west-end had larger home

ranges than those on the east-end

• Typical bobcat behavior

– Males typically overlap several females – Males-males and females-females don’t typically overlap

• Kiawah females overlapped 0-90% of their

home range with another female

– DNA suggested high relatedness for 90%

• verlap; denned 160 m and 85 m apart

– Abundant resources?

Bo Bobc bcat at Inte nterac ractions tions

Bo Bobcat bcat Mo Moveme vements nts

50 100 150 200 250 300 350 Dawn Day Dusk Night Time Period Avg Movement Rate (m/hr)

Day movemen ents ts depres essed, sed, no decre reas ase e at night ht

Hab abita itat t Selection ection

Habitat tat Rankin ing Time e Period

• d

Selected cted Avoide ded Diurnal nal Shrub Dune Forest est Develop lop Marsh sh Altered ered Noctu turna rnal Shrub Develo lop Dune Forest est Alter er Marsh sh

• Selected habitat differently day vs night
• Shrub selected over all other habitats
• Development selected and Altered not

avoided during nocturnal

Hab abita itat t & & Home

• me Ra

Range nge

• Female home ranges ↓ when % Shrub ↑
• EE vs WE differences may be inherent

differences in landform & Shrub availability

Bo Bobcat bcat Hab abita itat t Sui uitability tability

• Habitat Suitability Index

– Scoring system that is based on biology – Modified from Boyle and Fendley (1987) – Considered food, cover, and reproductive capability of habitat

Bo Bobcat bcat Hab abita itat t Sui uitability tability

Re Resear search ch Co Concl nclusions usions

• Kiawah bobcat = keystone

species

– A species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically – Natural regulation of deer

• Maintenance of bobcat

abundance

– Individual prey selection

Re Resear search ch Co Concl nclusions usions

• Conservation of suitable

habitat

– Shrub, edge – Understory – bobcats & rodents

• Local conservation and

education efforts are key

• Backyard habitat

– Native plantings that provide understory – Creation of “soft edges”

Cr Creating ating Bo Bobc bcat at Hab abitat itat

Kiawah iawah – Uni nique que in in Am America rica

Suburban bobcats do not make Kiawah unique

Kiawah iawah – Uni nique que in in Am America rica

Suburban bobcats do not make Kiawah unique

Kiawah iawah – Uni nique que in in Am America rica

Your efforts to maintain bobcats at a level where they function as a keystone species DOES!

Th Thank You! ank You!