Short-term Diversity of Mix-farmed Solitary Bees and Wasps (1997-2007) Department of Natural History, Royal Ontario Museum; [email protected]. Annual spp. numbers grew for 4 years or more. Censused species abundances varied, e.g., Hylaeus bees and Passaloecus wasps declined severely, and the Orchard Bee Osmia lignaria and Potter Wasp Symmorphus cristatus became pests. Consistent with this, ecological similarities across years revealed a clear trend in the changing species abundances, but overall biodiversity had not declined by 2007.
Transcript
Short-term Diversity of Mix-farmed Solitary Bees and Wasps (1997-2007)
Department of Natural History, Royal Ontario Museum; [email protected].
Annual spp. numbers grew for 4 years or more. Censused species abundances varied, e.g., Hylaeus bees and Passaloecus wasps declined severely, and the Orchard Bee Osmia lignaria and Potter Wasp
Symmorphus cristatus became pests. Consistent with this, ecological similarities across years revealed a
clear trend in the changing species abundances, but overall biodiversity had not declined by 2007.
1.Given a regional cavity-using fauna & a large data collection develop 3 different farmed communities by choosing the cavity sizes. 2. Analyse census counts, not samples, of nest starts. 3. Present (a) as a sum (Main Study '01-'07) & (b) as a special case (Jokers '01-'08).
DEVELOPMENT (a) MAIN STUDY (b)
“SAUGEEN” Flesherton
Smaller cavity widths 3.2, 4.8 mm.
'97 '98 '99 '00 '01 '02 '03 '04 '05 '06 '07
“MONASTERY”, King City
Medium cavity widths 4.8, 6.4, 8.0 mm.
'98 '99 '00 '01 '02 '03 '04 '05 '06 '07 '08
“JOKERS HILL”, Newmarket
Larger cavity widths 6.4, 8.0, 9.6 mm.
'01 '02 '03 '04 '05 '06 '07 '08
(b) Special case.
Main study: Species ranked by overall abundance (2001-7)
Same data to show varied yearly abundances.
All (n=23395) ‘01 ‘02 ‘03 '03 ‘05 ‘06 ‘07 Pool
Spp. list 19 20 24 25 25 25 25 25
Listing the spp. began in 1997, so it can take more than 3 years.
Bee + Wasp =
8 + 11 = 19
9 + 1 0 = 19
10 + 12 = 22
12 + 12 = 24
11 + 12 = 23
11 + 12 = 23
11 + 12 = 23
12 + 13 = 25
Annual spp. count is close to the list count, and stable.
Ecological similarity here compares each year’s abundances with year 2007. There is a clear yearly trend in the underlying pattern of spp. abundances, not chaotic variation, in the short term at least.An estimate for First Nests (0.76) suggests that what has been farmed is not exactly what was first trapped.
Started with empty gear in ’01. Listing the spp. can take years.
Bee + Wasp =
8 + 8 = 16
2 + 3 = 5
7 + 4 = 11
5 + 6 = 11
5 + 5 = 10
5 + 7 = 12
4 + 7 = 11
4 + 6 = 10
4 + 5 = 9
8 + 8 = 16
Fewer annual spp. than the list and unstable. Even the yearly spp. names vary. (Cavity sizes at the edge of the cavity range?)
Pielou evenness
0.58 0.31 0.35 0.51 0.46 0.52 0.64 0.67 0.67 0.56
Improving evenness is not very relevant given the varying spp. counts.
Bee/waspEntropy
1.01 2.13 1.71 1.34 1.93 0.94 0.98 0.68 0.56 0.92
As expected from the spp. counts this ratio is not stable.
JOKERS HILL n=5179 1
st ‘01 ‘02 ‘03 ‘04 ‘05 ‘06 ‘07 ‘08Pool
Steinh. Simil.
0.68 0.42 0.58 0.61 0.62 0.74 0.82 0.86
Ref0.77
The yearly spp. abundances differ from 2008’s. As in the main study there is a steady trend in annual similarity. (The years likely form a path in multiaxis spp. abundance space.)
Steinh. Simil.
Ref0.55 0.79 0.78 0.68 0.78 0.77 0.72 0.68 0.86
As in the Main Study, what is being farmed is not exactly what was first trapped. But despite the annual trends in blue above, the situation is not obviously worsening. (Probably because no major species has been extirpated.)
Short-term Diversity of Mix-farmed Solitary Bees and Wasps (1997-2007)
Department of Natural History, Royal Ontario Museum; [email protected].
Annual spp. numbers grew for 4 years or more. Censused species abundances varied, e.g., Hylaeus
bees and Passaloecus wasps declined severely, and the Orchard Bee Osmia lignaria and Potter Wasp
Symmorphus cristatus became pests. Consistent with this, ecological similarities across years revealed a
clear trend in the changing species abundances, but overall biodiversity had not declined by 2007.
(Thanks to C. Darling & G. Umphrey for motivation)
Hubbell neutral theory for crowded landscapes. No niches, no interactions.
An individual dies and is replaced by by another of a random species. Only individuals count. Species look after themselves. 4 non-arbitrary parameters : Bioreserve total population count, speciation rate, local community population count, immigration rate.
Current objections: Crowding is not all or none. It only occurs for the last half of the Main Study. There is no analogue to the seed bank -not all species are nesting at any given time. There is minor nest warfare when crowded. Cavity width is a major niche parameter. Which is the bioreserve and which the local community (the equipment or the ambient?) if natural nesting sites are rare as often informally stated (or are they hugely abundant if integrated over a very wide migration area)? Perhaps a sum of Hubble models for cavity widths might be testable.
Jokers Hill: Cavities empty early 2001. (N=5179)
After the initial increase, overall diversity was maintained 2001-7
