EcoSolutions Integrated Pest Management Service Report for May 2016

Overview:

It has been suggested that bats are restricted in their ability to contribute to

arthropod suppression within the agricultural sector primarily due to the lack of

available and suitable roost sites. (Long et al., 2006; Taylor, 2000). The provision of

artificial roost sites in the form of bat boxes, bat towers or bat Hotels have been

attempted since the early 20th century (Campbell, 1925; Tuttle et al., 2004), and has

produced mixed results. Bats have shown an acceptance for some of these artificial

structures and a resistance to others. Although some research has been undertaken

on the parameters which make these structures appealing or unappealing to bats

(Long, Kiser & Kiser, 2006; Tuttle, Kiser & Kiser, 2004; Vonhof & Barclay, 1996)

there is still a need for further research. The implementation of artificial roost sites

with the Levubu and Tzneen areas are in an attempt to establish occupancy potential

and additionally to ascertain the feasibility of insectivorous bats being utilised in the

control of stink bug, a agricultural pest prevalent in the area (Taylor.. ) Below is the

May 2016 service report.

The service undertaken by EcoSolutions in May 2016 was primarily to re-treat bat

houses and to check for occupancy and additionally, possible site selection

preference. In addition, EcoSolutions installed guano trays at the bat banks and

installed prototype rocket bat boxes to ascertain their potential for future occupancy.

Although covered in the report, for ease of reference, the important observations are

bulleted below.

• All of the Bat houses serviced in Levubu during May 2016 are either occupied, or

show signs of occupancy.

• The guano trays indicated bat occupancy in the form of guano beneath the bat

houses 30 minutes after installation. This occupancy was recorded in bat houses

that had previously been viewed as unoccupied. All sites should utilise guano trays

as a matter of course.

• We have provided an interactive map, showing sites, occupancy, orientation and

elevation. We are able to update and manage this map from our offices and all

participating farmers and interesting parties are welcome to add to this platform.

Please contact EcoSolutions for editing capabilities.

• The method of ascertaining bat house occupancy through the use of mirrors and

torches appears to have real limitations.

• The importance of an available water source for bats and for bat houses placement

was a consideration at the installation stage of this project. The map provides

distance to water information as does this report.

• The service of the bat houses remains an essential component to successful

occupancy.

• In our conclusion we suggest the service of other bat houses in this programme as

soon as possible. At this service, both Guano trays and rocket boxes should be

incorporated.

Bat Occupancy for May 2016 on farms in the Levubu Region:

Number (n) of individual bats in occupied bat boxes for May 2016 on farms in the Levubu Region:

Farm Name:

Muirhead & Roux

Type of Box Bank Site 1 Bank Site 2 Slimline SiteRocket Box Site 1

Rocket Box Site 2

Coordinates23°03’20’’S 30°08’58’’E

23°03’12’’S 30°08’26’’E

23°03’12’’S 30°08’55’’E

23°03’20’’S

30°08’58’’E

23°03’12’’S

30°08’55’’E

6-Chamber n (2) n (6)

Nursery n (3) n (1)

Old George

Slimline Guano

Rocket BoxNewly In-stalled

Newly In-stalled

Total n (5) n (7) Unconfirmed None None

Farm Name:

Amana

Type of Box Bank Site 1 Bank Site 2 Slimline SiteRocket Box Site 1

Rocket Box Site 2

Coordinates

23°06’49’’S

30°17’27’’E

23°06’40’’S

30°17’23’’E

23°06’43’’S

30°17’17’’E

23°06’49’’S

30°17’27’’E

23°06’40’’S

30°17’23’’E

6-Chamber n (3)

Nursery n (6) n (4)

Old George3 Bush- ba-bies n (2)

Slimline Guano

Rocket BoxNewly In-stalled

Newly In-stalled

Total n (9) n (6) Unconfirmed None None

Farm Name:

Integrifolia

Type of Box Bank Site 1 Bank Site 2Rocket Box Site

Slimline Site 1

Slimline Site 2

Coordinates

23°05’01’’S

30°20’59’’E

23°05’25’’S

30°20’26’’E

23°05’01’’S

30°20’59’’E

23°05’14’’S

30°20’49’’E

23°05’12’’S

30°20’49’’E

6-Chamber n (4)

Nursery n (12)

Old George n (2)

Slimline Guano  Guano

Rocket BoxNewly In-stalled

Total n (4) n (14) None Unconfirmed Unconfirmed

A total number of 45 individual bats was recorded in May 2016.

Occupancy and Bat Box Orientation:

Bird and bat species may select their nesting sites in specific locations and orienta-tions. This can maximise their chances to successfully breed. For example, east-fac-ing nesting sites are warmed in the morning, south-facing ones receive the most amount of sunlight, and north-facing ones receive the least.

At each site, the orientation of the bank box sites and slimline box sites were noted based on the direction the entrance of the bat house was facing. Rocket box sites are open at the bottom, therefore, the orientation is invalid.

The individual bat numbers relating to the orientation of the bank sites are repre-sented below.

Bat Occupancy of Bank Sites Related to Orientation

Orientation Number of Bank Boxes Individual Bat Occupancy

North East 33% n (16)

West 17% n (5)

South West 17% n (6)

South 17% n (4)

South East 17% n (14)

North East; 2; 33%

West; 1; 17%South West; 1; 17%

South ; 1; 17%

South East; 1; 17%

Number of Bank Boxes

North East West South West South South East

Occupancy and Distance to Water

Bat Occupancy of Bank Sites relating to their Distances to Water

DistanceBank Site Boxes within each Distance Range Individual Bat Occupancy

<50m 33% n (14)

50m-100m 17% n (7)

100m-500m 33% n (10)

>500m 17% n (14)

North East; 16; 36%

West; 5; 11%South West; 6; 13%

South ; 4; 9%

South East; 14; 31%

Individual Bat Occupancy

North East West South West South

South East

Occupancy

Occupancy was recorded at all bat bank sites. Preference was recorded for the

Nursery and 6 chamber bat house design. The “Old George”, a popular bat house

design from the USA, has only recorded occupancy at one site with 2 individual bats

observed. In one of the “Old George” boxes, a family of bush babies was recorded.

The lack of occupancy in the “Old George” boxes may well be a result of the more

intricate sleeve design within the box which makes bat observation difficult.

Recording occupancy within the slimline boxes is difficult. The single chamber and

thickness of the box makes visual inspection very difficult. The presence of Guano

beneath these boxes indicators the presence of bats either currently or in the past.

The mounting of guano trays to the walls beneath the slimline bat houses should be

undertaken during the next service visit.

Artificial roost sites are used in various ways by different bat species, as well as by

individuals of the same species. Bat houses may be used as maternity roosts,

hibernacula, bachelor roosts and nocturnal “resting” roost sites. The requirement

parameters between a maternity roost site and a ‘resting” site during a night of

hunting, will differ. Bats are also known to move from one roost site to another as a

<50m; 14; 31%

50m-100m; 7; 16%100m-500m; 10; 22%

>500m; 14; 31%

Bank sites occupancy and distance to water

<50m 50m-100m 100m-500m >500m

consequence of predation pressure (the roost has been identified and is frequently

visited by a predator of bats, i.e. a cat, or genet), by parasite pressure (increased

mite and or lice numbers), or proximity to prey (bats will move to sites with higher

insect numbers for consecutive nights in order to maximise feeding opportunity). It

is for these reasons, in conjunction with box design preference, that different box

designs were used in the Levubu, Tzaneen projects.

The interactive map shows all occupancy recorded as at the May 2016 service.

Guano collection trays

The guano trays at all of the bat banks were installed by EcoSolutions as part of our

Research and development undertaking. The value of these guano trays was quickly

established. Trays under bat houses classified as unoccupied, within 30 minutes of

the tray installation, were reclassified as occupied. Guano was collected from

beneath the boxes almost immediately, indicating the presence of bats therein. The

lack of provision of guano trays at the bat houses at the time of installation was an

oversight and should be corrected as soon as possible. The value of the guano trays

are two-fold:

• The presence of guano indicates to farmers who visit the site that the bat houses are occupied without ladders, mirrors and torches.

The collected guano can also be used for DNA markers, which eases the

identification of bat species occupying bat box sites. Trays are especially valuable to

the Slimline Box set-up, due to its design

inherently limiting visual inspection. The only

Slimline Sites where no guano was recorded

were on the Integrifolia Sites. The absence of

bat occupancy on the Integrifolia Slimline

Sites is explained by the newly-erected fence,

that was placed one metre from the boxes.

The close proximity of the fence to the Slimline Boxes may restrict access of the box

by bats.

Rocket Boxes were installed on all farms in the Levubu region as a prototype bat

box. The design of the Rocket Box allows access for bats from all directions,

therefore orientation becomes arbitrary.

From the above data and graph, there is a relatively even distribution of bat

occupancy regarding the ranges of distances to water for each Bank Site. The

greatest percentage of bat occupancy to distance from water is shared between the

closest range, being below 50 m to the closest water source, and the farthest range,

being over 500 m to the closest water source. This indicates to no significant

differentiation between distances to water and bat occupancy of bat box sites.

The data collected in the May 2016 inspection is valuable, especially when looking at

the number of individual bats and their distance to the closest water source, due to

the data being distributed evenly and thus no significant correlation is found. Further,

a clear preference is displayed by individual bats choosing east-facing bat boxes.

Lastly, the importance of utilising guano trays is obvious, because it creates a means

to record bat occupancy especially with Slimline Sites and provides a method of

identifying bat species from bat box sites.