Habitat Needs of Bats in Sandhills

Transcription

1 Habitat Needs of Bats in Sandhills Holly Ober Dept of Wildlife Ecology & Conservation University of Florida How many kinds of bats live in FL? a) 1,100 b) 48 c) 13 1

2 How many kinds of bats live in Florida? a) 1,100 = # of bat species in the world b) 48 c) 13 How many kinds of bats live in Florida? a) 1,100 = # of bat species in the world b) 48 = # of bat species in the U.S. c) 13 2

3 How many kinds of bats live in Florida? a) 1,100 = # of bat species in the world b) 48 = # of bat species in the U.S. c) 13 = # of bat species in Florida How many kinds of bats live in Florida? a) 1,100 = # of bat species in the world b) 48 = # of bat species in the U.S. c) 13 = # of bat species in Florida d) 11 = # of bat species in sandhills habitat in Florida 3

4 There is a lot of diversity among the bats of Florida! Furry tail membrane Non-furry wing membrane 4

5 4 Florida bats have furry tail membranes Yellow bat Red bat Seminole bat Hoary bat Foliage-roosting bats 5

6 3 Florida bats have long tails Brazilian free-tailed bat Velvety free-tailed bat Florida bonneted bat Species likely to occur in FL sandhills 6

7 Managing habitat for bats 1. Roosts 2. Foraging areas Roosting Preferences Species Tree cavities Tree foliage Spanish moss Caves Human structures Big brown Evening Rafinesque big-eared Southeastern Brazilian free-tailed Tricolored Hoary Eastern red Seminole Northern yellow Gray 7

8 Roosting Preferences Species Tree cavities Tree foliage Big brown Evening Rafinesque big-eared Southeastern Brazilian free-tailed Tricolored Hoary Eastern red Seminole Northern yellow Gray Green = pines Purple = tupelos Orange = hardwoods Cavity-roosting & bark-roosting bats Trees Large diameter Taller than surrounding Short midstory/understory Veg community Pine stands Mixed pine-hardwood stands Bottomland hardwood swamps 8

9 Diet Preferences Species Lepidoptera Coleoptera Diptera, etc. Big brown Evening Rafinesque big-eared Southeastern Brazilian free-tailed Tricolored Hoary Eastern red Seminole Northern yellow Gray Foraging Abilities The size and shape of the wings relative to the weight affect foraging abilities Aspect ratio = (wingspan) 2 / wing area Wing loading = weight / wing area High aspect ratio Low aspect ratio Low wing loading High wing loading 9

10 Ecomorphology of bats 1. Long, pointed wings and heavy body g p high aspect ratio Above the canopy high wing loading flight is inexpensive adapted for fast flight in open habitats Brazilian free-tailed, big brown, red, yellow, hoary 2. Short, rounded wings and low weight In the understory low aspect ratio low wing loading adapted for slow flight close to or among vegetation Rafinesque big-eared, tri-colored, Southeastern Effects of Forest Management Activities on Bats 1. timber management 2. prescribed fire 10

11 Timber management Larger bats prefer thinned over unthinned stands prefer edges over intact forest stands Smaller bats indiscriminate 11

12 How does fire influence bats? Fire creates snags Increases abundance of roosts for 7 species Fire clears out the understory Increases foraging space for larger bats Fire increases herbaceous vegetation Increases abundance of some insects What is known about bats & fire in FL? 12

13 Investigated bat activity in areas with 3 categories of fire history 1 2 years 3 5 years >8 years 13

14 Nocturnal Flying Insect Response to Prescribed Fire all insects (mg) Lepidoptera (mg) year 3-5 years >8 years Bat Response to Prescribed Fire year 3-5 years >8 years above canopy (passes/night) 14

15 Bat Response to Prescribed Fire below canopy (passes/night) year 3-5 years >8 years Take home messages - fire 18 Niche differentiation! Above vs below canopy Large spp. above; small spp. below year 3-5 years >8 years above canopy (passes/night) 4 2 Fire return interval year 3-5 years >8 years High frequency = more insects, more foraging space, more roosts o Good for all species Low infrequency: more Lepidoptera, less foraging space o Less competition, so good for small species 8 6 below canopy (passes/night) 15

16 Managing Sandhills for Bats Essential resources 1 R i 1. Roost sites Pines/hardwoods/Tupelo, tree cavities, Spanish moss, caves 2. Foraging habitat Thinning, prescribed fire 16