Vertical Distribution of Spiders (Araneae) on a Tropical Island

Eric Brown Fall 2008 Advisor: Dr. Bruno Nyundo Academic Director: Helen Peeks Table of Contents

TABLE OF CONTENTS - 2 -

ACKNOWLEDGEMENTS - 3 - Deleted: - 3 - ABSTRACT - 5 -- 5 - Deleted: - 3 - INTRODUCTION - 6 -- 6 - Deleted: - 3 - STUDY AREA - 9 -- 9 - Deleted: - 3 - METHODS - 11 -- 11 - Deleted: - 3 - RESULTS - 14 -- 14 - Deleted: - 3 - DISCUSSION - 24 -- 24 - Deleted: - 3 - CONCLUSION - 27 -- 27 - Deleted: - 3 - RECOMMENDATIONS - 28 -- 28 - Deleted: - 3 - WORKS CITED - 29 -- 29 - Deleted: - 3 - APPENDICES - 31 -- 31 -

- 2 - Acknowledgements

This paper would not have been possible without the support of many people. In no particular order I want to thank: the four other Misali Island castaways—Matt, Lisa,

Madeline, and Aisha—for keeping me entertained and in a good mood, as well as for an

(almost) neverending supply of Nutella and peanut butter, Ilka for her help finding a stereoscope to use at IMS, Ali Said for information about staying on Misali and final approval for such, the Misali Rangers—Khamis, Said, Ali, Mohammed, Haji, Abbas—for food, bao, companionship, a never-ending supply of tea, boat rides, the generator, making who knows how many phone calls in order to set up all of the logistics for my return to

Unguja, and extreme patience (and a good sense of humor) with my Kiswahili, the fishermen and ascaris for their assistance with my study (no matter what time of the night), Filbert and Hassan from Fundu Lagoon for leftovers, good conversation, and generosity that knows no bounds, Dr. Narriman Jiddawi for her assistance finding computer time at IMS, advice on advisors and a note to the fisheries department explaining my situation and asking permission for me to stay on Misali for my study, the

Department of Fisheries for supporting me by allowing me free reign on Misali Island to perform my study, the guards at IMS for making it available all night, Robert Colwell for providing the EstimateS 7.5.1 population estimator software free of charge, Ali Seif at the

Mkoani Guest House for allowing me to hang out there for half of a day while awaiting the ferry and for buying me my ferry ticket back to Unguja, Hamis for helping me find and purchase pipes to use as pitfall traps, Ali for his help getting zip-lock bags with which to catch spiders and for seeing me off at the ferry to Pemba, Helen for her patience with my work schedule, for supporting and approving my proposal, for extending office

- 3 - hours to allow for more computer time, for help finding where to buy supplies, and for a semester’s worth of ISP ideas, Said for assistance finding an advisor, keeping the tax collectors at bay, advice on ferry tickets, and being available to answer ANY questions I had at ANY time—even if he was suffering—and always with his trademark sense of humor and good cheer, and finally my advisor, Dr. Bruno Nyundo from the University of

Dar-es-Salaam, without whom I would have been lost, for agreeing to be my advisor, applying his expertise to my project, offering UDSM resources, being available at all times, being flexible and, in particular, helping me develop a valid methodology remotely, and with limited contact opportunities. Furthermore, I’d like to thank everybody who I have neglected to specifically mention above—believe it or not, there are many—who has helped me in any way during the study period. Your assistance has been invaluable and will not be forgotten.

- 4 - Abstract

The distribution of spiders into vertical layers was studied on Misali Island. In particular, differences in diversity, species richness, abundance, and body length were analyzed. A variety of collection methods were used in order to capture as many different species as possible from three levels of forest: leaf litter, groundcover (up to

1m), and understory (up to 3m). After being sorted to the morphospecies level, the spiders were cataloged and several statistical tests were run. These tests show that spiders do show species-level stratification between different levels of forest. They also pointed towards a particularly firm dividing line between species of the understory and those of the groundcover which discourages crossover.

- 5 - Introduction

Tropical islands are known as breeding grounds for both biodiversity and unique ecological situations because they combine two environments with already elevated levels of diversity and inimitability—the tropics and islands (Sadler, 1999). The vast distances of ocean separating islands acts as a biological barrier for many organisms.

Over time, this barrier results in an ecosystem that develops unlike any other—no two islands have the same ecological situations, just as no two continents do. Since islands occur on a smaller scale than continents, however, their study allows a more complete look at a unique ecosystem.

Furthermore, the vertical microhabitats of forests have been established as containing unique organisms that only exist at certain different vertical levels. This has been proven for a variety of organisms, including butterflies (Fermon et al., 2003), moths

(Brown, 1997), and bats (Bernard, 2001).

Since vertical layering works with butterflies, moths, and bats it is likely that some vertical stratification will be detected in this study.

Only a few past studies have focused specifically on vertical spider distribution.

These include Sorensen (2001), Pekar (2005), Wagner et al. (2003), and Schipper er al.

(2007). However, none of these studies attempt to look at vertical spider stratification within a microhabitat itself—an island. Because this reduces variables and simplifies the working ecosystem, an island is a good place to start in order to begin building knowledge about vertical spider distribution.

Researchers have determined that the tropical canopy holds a high proportion of the number of arthropod species existing in the forest (Erwin, 1982). Furthermore,

- 6 - researchers have identified the vertical distribution of spiders to be similar to that of other arthropods (Sorensen, 2001). We can use this information to develop informed hypotheses about the vertical microhabitats.

In that vein, this study endeavors to unveil the vertical distribution of spider species and spider attributes that vary on a vertical basis. It attempts to answer the following questions in an effort to uncover information about the vertical zones that spiders segregate themselves into on Misali Island:

1) Is the vertical distribution of spiders on Misali Island different in different

vertical zones?

2)Does spider diversity differ based on vertical zones?

3) Does species richness differ based on vertical zones?

4) Does spider abundance differ based on vertical zones?

5) Does spider body length differ based on vertical zones?

This study is important because it adds to the existing scholarship on spiders of

Tanzania. This topic is not widely studied, and the gaps in knowledge are much larger than the pieces filled in. For example, Sorensen (2001) found that 80% of his collected spiders were not taxonomically defined yet. This presents a large unknown in the area of scholarship. Learning about these undiscovered and barely-discovered organisms can be potentially beneficial to humans for reasons yet undiscovered or for a variety of discovered reasons: direct—such as medical treatment—and indirect—such as mosquito population control. These reasons more than justify the time and expense put into this

- 7 - project.

- 8 - Study Area

Spiders were collected on Misali Island, an island in the Zanzibar archipelago, over the course of three weeks. The island is located ~10 km off of the west coast of

Pemba Island, centered at coordinates XXXXXXX (Abdullah et al., 2000). The entirety of the island, along with a portion of adjacent coral reef, is designated a Marine Protected

Area, and is part of the Pemba Channel Conservation Area (PECCA). At .9 km, the island represents all of the terrestrial protected area within PECCA (Abdullah et al.,

2000). The island is uninhabited except for the four rangers, several soldiers and fishermen who camp in two areas on the island at any one time. The island is covered with sections of sandy beach, verdant forest, and coral rag, and has little elevation change, with a maximum elevation of 6m (Google Earth). Sampling was performed in

November, 2008, during the short rainy season of November/December in three vertical layers—leaf litter, groundcover and understory—within three separate 400 m2 plots on the island. The three plots deliberately represent three different vegetation zones on

Misali in order to collect the widest variety of spider fauna. The sites had the following characteristics:

Site #1: Canopy height ~10 m, understory density ~40%, groundcover ~30%, leaf litter

depth ~3 cm. This site was located near (but did not include) the Bendera caves

on the west side of the island. The area was entirely covered with topsoil.

Site #2: Canopy height ~6 m, understory density ~35%, groundcover ~25%, leaf litter

depth ~2 cm. This site was located on the north end of the island and a portion of

- 9 - it included the edge of a mangrove area. However, it was not an intertidal area.

The soil makeup was partially coral rag, partially topsoil.

Site #3: Canopy height ~8m, understory density 85%, groundcover ~50%, leaf litter

depth ~4 cm. This site was located in the southwest portion of the island, close to

the Ranger Station and Visitor’s Center. This was the most topographically

varied of the sites, with a coral rag wall raising part of the area ~1.5 m above the

rest. The area was mostly covered with a thin layer of topsoil, but there were

several portions where coral rag peeked through.

In all sampled areas the forest showed no evidence of disturbance by humans, save for the nature trails that run adjacent to the sampling areas.

- 10 - Methods

Spiders were collected by one researcher during a 15 day period between

November 9, 2008 and November 24, 2008. The three sites were divided into three vertical zones: leaf litter, groundcover (up to 1m), and understory (up to 3m). The canopy was not sampled because of the cumbersome equipment required and the remote location of the study area.

A variety of methods were used in order to collect the widest variety of spiders, since each method tends to collect a different group (Bruno Nyundo, personal communication). Collection was divided into sections; the collector collected solely from one of the three vertical zones at one time. Each sample consisted of thirty minutes of intense sampling by the collector. Four samples were performed in each vertical zone in each site. Leaf litter was sampled using the stratified litter grab technique (Wagner,

2003). This technique involves collecting all leaf litter from a relatively small patch of the sampling area—in the case of this experiment between 1 and 2 m2, approximately the amount that can be sorted through in ½ hour—and placing it on a light-colored piece of fabric. After placement on the piece of fabric the litter was then sorted through in order to identify and isolate the spiders located within. Groundcover was sampled using ocular detection, whereby the collector identified spider webs and isolated the spiders, as well as groundcover beating, whereby the collector beat the groundcover above a large white sheet that the spiders would fall onto. This allowed for easy detection and capture.

Similarly, the understory was sampled using ocular detection and understory beating techniques.

- 11 - Spiders were captured and collected using small zip-lock bags, which were then used for preservation of the specimens until which point they could be transported back to the lab at the Institute of Marine Science (IMS) in Stone Town, Zanzibar for classification.

Spiders were divided into morphospecies using a stereoscope located at IMS.

They were divided based upon size, coloration, and eye placement. Morphospecies was determined to be an adequate level of identification because of the high correlation between spider species and morphospecies (Bruno Nyundo, personal communication) and the incomplete knowledge of spider fauna (Sorensen, 2003).

After identification to morphospecies the body lengths of the specimens were measured under the stereoscope. The measurements were rounded to the nearest 1/10 of a millimeter. Average size and standard deviation were calculated for the overall sample and each subset of the overall sample.

Statistical analysis was performed using EstimateS 7.5.1 (Colwell, 1997). Species diversity was calculated using the Shannon Index (Shannon, X), and species richness was calculated using Chao 1 (Chao, 1984). EstimateS 7.5.1 was also used to calculate standard deviation for the Chao 1 figure. Chao 1 was selected because it allows comparisons to be made with similar studies that have used the Chao 1 estimator and because it uses the number of singletons, doubletons, and observed species in order to calculate the species richness for each area, making it easy to replicate in future studies.

Chao 1 was calculated using the bias-corrected formula unless the estimated CV was >.5, in which case, as per Anne Chao’s suggestion, the classic formula was used to calculate

Chao 1, with the larger of the Chao 1 or ACE values being chosen as the best estimate for

- 12 - abundance-based richness.

- 13 - Results

Sampling efforts resulted in the collection of 210 spider specimens. Split into vertical zones 129 individuals (61.4%) were found in the leaf litter, 35 individuals

(16.7%) were found in the groundcover layer (up to 1m), and 46 individuals (21.9%) were found in the understory layer (1-3m) (see Figure 9). Divided instead into collection areas 52 individuals (24.8%) were found at Site 1, 120 individuals (57.1%) were found at

Site 2, and 38 individuals (18.1%) were found at Site 3 (see Figure 9).

These individuals were determined to belong to a total of 40 different morphospecies. 16 of them were found in the leaf litter, 20 were found in the groundcover, and 21 were found in the understory. 24 of these were found at Site 1, 22 were found at Site 2, and 21 were found at Site 3 (see Figure 10).

Measurements of spider body lengths resulted in an average overall body length with standard deviation as well as average body lengths and standard deviations for leaf litter, groundcover, understory, Site 1, Site 2, and Site 3 (see Table 1, Figure 13, Figure

14, Figure 15).

Over all vertical zones and collection areas 13 singletons (morphospecies where only 1 individual was found) and 11 doubletons (morphospecies where only 2 individuals were found) were identified (see Figure2). Considering only the leaf litter results, there were 6 singletons and 5 doubletons. 11 singletons and 5 doubletons were found in the groundcover, and 12 singletons and 4 doubletons were found in the understory. In terms of collection areas, 14 singletons and 3 doubletons were found at Site 1, 13 singletons and 2 doubletons were found at Site 2, and 14 singletons and 3 doubletons were found at

Site 3.

- 14 - The statistical analysis by EstimateS 7.1.5 of the data resulted in an estimate for the number of species present in the whole 1200 m2 sampling area of 46.5 with a standard deviation of 4.6, as well as estimates for the number of species present in the leaf litter, the groundcover, the understory, Site 1, Site 2, and Site 3 (see Table 1, Figure 16).

Further statistical analysis using the same software resulted in an overall species diversity figure (H’) on the Shannon index (Shannon, 1948) of 2.67. It also resulted in an

H’ for leaf litter, groundcover, understory, Site 1, Site 2, and Site 3 (see Table 1, Figure

11, Figure 12).

- 15 -

(H') (H') 1.45 2.84 2.70 2.81 1.53 2.80 2.67 n Index) n Index) (Shanno Diversity Diversity 18.5 +/- 2.8 2.8 +/- 18.5 5.8 +/- 27.9 4.6 +/- 46.5 Chao 1 Mean 39.0 +/- 14.4 56.7 +/- 26.3 64.3 +/- 38.5 53.7 +/- 26.3 5 6 4 3 2 3 11 Doubletons Doubletons 6 11 12 14 13 14 13 Singletons Singletons 16 20 21 24 22 21 40 Morphospecies Morphospecies 35 46 52 38 129 120 210 Individuals Individuals 1.8 +/- 1.0 1.0 +/- 1.8 1.5 +/- 3.0 2.7 +/- 2.9 1.8 +/- 2.6 1.5 +/- 1.9 1.7 +/- 2.8 1.7 +/- 2.2 Mean Length (mm) (mm) Length Mean 6 5 8 5 6 X 11 Unique Species Species Summary of variables (+/- standard deviation) deviation) standard (+/- Summary variables of #1 #1 #2 #3 Area Overall Overall Leaf Litter Litter Leaf Understory Understory Groundcover Groundcover Table 1: Table

- 16 - # Individuals Collected by Morphospecies

43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 27 26 25 24 23 22 20 19 18

Morphospecies 17 16 15 14 13 12 11 9 8 7 6 5 4 3 2 1 0 102030405060708090 # Individuals

Figure 1

Singletons and Doubletons by Area

Singletons 8 Doubletons Number

0 Leaf Litter Groundcover Understory #1 #2 #3 Overall Area

Figure 2

- 17 - 1 2 1 2 # Individuals by Morphospecies in Leaf Litter 3 4 # Individuals by Morphospecies in Site #1 3 4 5 6 5 6 7 8 7 8 9 11 9 11 12 13 12 13 14 15 14 15 16 17 16 17 18 19 18 19 20 22 20 22 23 24 23 24 25 26 25 26 27 29 27 29 30 31 30 31 32 33 32 33 34 35 34 35 36 37 36 37 38 39 38 39 40 41 40 41 42 43 42 43 Figure 3 Figure 4

1 2 1 2 # Individuals by Morphospecies in Groundcover 3 4 # Individuals by Morphospecies in Site #2 3 4 5 6 5 6 7 8 7 8 9 11 9 11 12 13 12 13 14 15 14 15 16 17 16 17 18 19 18 19 20 22 20 22 23 24 23 24 25 26 25 26 27 29 27 29 30 31 30 31 32 33 32 33 34 35 34 35 36 37 36 37 38 39 38 39 40 41 40 41 42 43 42 43 Figure 5 Figure 6

1 2 1 2 # Individuals by Morphospecies in Understory 3 4 # Individuals by Morphospecies in Site #3 3 4 5 6 5 6 7 8 7 8 9 11 9 11 12 13 12 13 14 15 14 15 16 17 16 17 18 19 18 19 20 22 20 22 23 24 23 24 25 26 25 26 27 29 27 29 30 31 30 31 32 33 32 33 34 35 34 35 36 37 36 37 38 39 38 39 40 41 40 41 42 43 42 43 Figure 7 Figure 8

- 18 - # Individuals by Area

140

120

100

60 Number of Individuals 40

0 Leaf Litter Groundcover Understory #1 #2 #3 Area

Figure 9

# Morphospecies by Area

10 # Morphospecies

0 Leaf Litter Groundcover Understory #1 #2 #3 Area

Figure 10

- 19 - Diversity (Shannon Index) by Vertical Zone (H')

2.5

1.5 Diversity (H') Diversity

0.5

0 Leaf Litter Groundcover Understory Overall Vertical Zone

Figure 11

Diversity (Shannon Index) by Site (H')

2.5

1.5 Diversity (H') Diversity

0.5

0 #1 #2 #3 Overall Site

Figure 11

- 20 - Average Body Length (mm) by Vertical Zone

3.5

3.0

2.5

2.0

1.5

Average Body Length (mm) Length Body Average 1.0

0.5

0.0 Leaf Litter Groundcover Understory Overall Vertical Zone

Figure 13

Average Body Length (mm) by Site

3.0

2.5

2.0

1.5

1.0 Average Body Length (mm) Length Body Average

0.5

0.0 #1 #2 #3 Overall Site

Figure 14

- 21 - Avg. Standard Deviation in Body Length by Area (mm)

3.0

2.5

2.0

1.5

1.0 Avg. Standard Deviation (mm)

0.5

0.0 Leaf Litter Groundcover Understory #1 #2 #3 Overall Area

Figure 15

Chao 1 Mean by Area

70.0

60.0

50.0

40.0

30.0 Chao 1 Mean

20.0

10.0

0.0 Leaf Litter Groundcover Understory #1 #2 #3 Overall Area

Figure 16

- 22 -

Figure 17

- 23 - Discussion

Because of the eclectic variety of spider species and habitats it is difficult to use methods which collect specimens equally from all microhabitats. This, combined with the high number of singletons and doubletons found in this study, supports the nearly unavoidable likelihood of incomplete sampling in this study. In order to reach the goals of this study—to identify and analyze elements of the vertical microhabitats of spiders including species richness, species diversity, and species size—a variety of methods were used in an attempt at the most complete collection of specimens possible. The high number of singletons and doubletons (see Figure 2) and the high number of taxonomically described and as-yet undescribed species highlights the struggle to collect adequate samples in order to draw reliable conclusions.

Regardless of the limitations in the application of the data, and similar to the way that different species of bats inhabit different vertical levels of the canopy (Handley,

1967, Bernard, 2001) or spiders inhabit different layers of leaf litter (Wagner, 2003), and in concurrence with Sorensen (2003), the results show that spiders show species-specific vertical stratification between different levels of forest.

This is perhaps shown best by the number of unique species in each vertical habitat (see Table 1, Figure 17). A high proportion—more than half—of all morphospecies found were found only in one of the three vertical layers identified in the

Methods section. Only one morphospecies was found in all three vertical layers, and that morphospecies only contained one specimen in the understory, suggesting that perhaps it was transient and does not ordinarily inhabit that vertical layer. These results comprise a compelling argument for vertical microhabitats for spiders.

- 24 - The results show an imbalance in the number of individuals per area (see Figure

9). As seen in the graph, the numbers of individuals in the groundcover and understory layers are relatively equal, but the number of individuals in the leaf litter is much greater.

The same applies to Site 2 in the area comparison. However, instead of suggesting a higher abundance of individuals within the leaf litter and Site 2, this is likely the result of a highly localized population boom accounted for by the 82 members of morphospecies 3 found in the leaf litter of Site 2. The offending morphospecies can be observed in Figure

1. No conclusions regarding the abundance of individuals in different vertical zones may be drawn from these results.

We can see from the data that, while understory and groundcover shared many morphospecies, understory and leaf litter shared only one morphospecies. As predicted, the groundcover had the fewest number of unique species (see Table 1, Figure 17). This is logical because being sandwiched between the leaf litter and understory layers there is more room for overlap. Surprising, however, was the much higher number of unique species in the understory—11. This number in particular suggests a more defined divide between understory and groundcover than expected.

Sorensen (2003) concludes that the vertical stratification pattern of spiders is much like the patterns of other invertebrates. Since researchers report that the canopy is home to the most arthropods (Erwin, 1982). This hypothesis is supported by the results of the statistical analysis of the diversity of each vertical zone, which calculated the leaf litter diversity to be the lowest amongst itself, groundcover, and understory, and would follow if there were more species represented higher up, since the diversity would be higher.

- 25 - In line with this thinking were the results from the statistical analysis regarding estimated species richness, which show a step up from leaf litter to groundcover to understory (see Table 1, Figure 16). Species richness, being the number of estimated species, is therefore highest in the understory, where the highest concentration was expected to be found. It is not likely that this difference is due to the large number individuals in morphospecies 3 that were found mostly in Site 2 because the values for

Site 1, 2, and 3 were relatively similar. If morphospecies 3 were responsible for the lower leaf litter index then it would resulted in a lower Site 2 index as well; but it did not

(see Figure 16).

Finally, the body length by vertical zone results show the leaf litter zone with a lower average body length than the other two, which are similar numbers. However, this is likely, once again, to be due to the extreme localized density exhibited by morphospecies 3 (see Figure 1). Since the average lengths are more or less the same, more meaningful is the fact that the standard deviation of the average body length increased going vertically up from leaf litter to understory (see Figure 15) This shows that during this study on Misali Island more larger specimens were captured in the understory, but has implications for future hypotheses.

- 26 - Conclusion

Spiders show species-specific vertical stratification between different levels of forest. As hypothesized, the highest vertical level, the understory, was found to have the highest level of species richness, although the relative ranking in terms of diversity was lower than expected. Furthermore, spiders in the understory were found to have a greater standard deviation for body length than their compatriots in the groundcover vertical zone or the leaf litter.

Additionally, the unique species data pointed to a specifically firm dividing line between understory and groundcover. Knowledge of this division could be further refined using methods which either measured the precise height from which they were collected or created smaller vertical zones than used here.

- 27 - Recommendations

There are several follow-up studies that can build upon what has been learned from this project. First, more research is needed on whether the leaf litter, groundcover, or understory holds the most individuals because the results here were skewed by an outlying variable. Ideally, many more samples would by taken—somewhere between

3000 and 5000.

- 28 - Works Cited

Abdullah, Ali, Ali Said Hamad, Ali Mbarouk Ali and Robert G. Wild. 2000. Misali Island, Tanzania – An Open Access Resource redefined. 8th Biennial Conference of the International Association for the Study of Common Property (IASCP).

Basset, Yves. 2001. Invertebrates in the canopy of tropical rain forests How much do we really know?. Plant Ecology. 153:87-107.

Bernard, Enrico. 2001. Vertical Stratification of Bat Communities in Primary Forests of Central Amazon, Brazil. Journal of Tropical Ecology. 17:115-126.

Borges, Paulo A. V. and Joerg Wunderlich. 2008. Spider biodiversity patterns and their conservation in the Azorean archipelago, with descriptions of new species. Systematics and Biodiversity. 6:249-282.

Buddle, Christopher M. and Michael L. Draney. Phenology of Linyphiids in an Old-Growth Deciduous Forest in Central Alberta, Canada . 2004. Journal of Arachnology. 32:221- 230.

Chao, A. 1984. Nonparametric estimation of the number of classes in a number of classes in a population. Scandinavian J. Stat. 11:265-270.

Chao, A. 1988. Estimating Animal Abundance with Capture Frequency Data. The Journal of Wildlife Management. 52:295-300.

Daniels, C., E. Fanning and D. Redding. 2003. Marine Resource Management for Misali Island: Preliminary Analysis by Frontier-Tanzania. Western Indian Ocean J. Mar. Sci. 2:85:93.

De Omena, Paula M. and Gustavo Q. Romero. Fine-scale microhabitat selection in abromeliad-dwelling jumping spider (Salticidae). Biological Journal of the Linnean Society. 94: 653-662.

DeVries, Philip J., Debra Murray and Russell Lande. 1997. Biological Journal of the Linnean Society. 62:343-364.

Erwin, T. L. 1982. Tropical forests: their richness in Coleoptera and other arthropod species. Col. Bull. 36: 74–75.

Fermon, Heleen, M. Waltert and M. Mühlenberg. 2003. Movement and vertical stratification of fruit-feeding butterflies in a managed West African rainforest. Journal of Insect Conservation. 7:7-19.

Handley, C. 0. 1967. Bats of the canopy of an Amazonian forest. Atas do Simposio sobre Biota Amazonica. 5:211-215.

- 29 -

Moring, J. Bruce and Kenneth W. Stewart. Habitat Partitioning by the Wolf Spider (Araneae, Lycosidae) Guild in Streamside and Riparian Vegetation Zones of the Conejos River, Colorado. 1994. Journal of Arachnology. 22:205-217.

Paetzold, Achim, Michelle Lee and David M. Post. 2008. Marine resource flows to terrestrial arthropod predators on a temperate island: the role of subsidies between systems of similar productivity. Oecologia.

Pekar, Stanno. 2005. Horizontal and Vertical Distribution of Spiders (Araneae) in Sunflowers. Journal of Arachnology. 33:197-204.

Sadler, John P. 1999. Biodiversity on Oceanic Islands: A Palaeoecological Assessment. Journal of Biogeography. 26:75-87.

Rubio, Gonzalo D. Do Spider Diversity and Assemblages Change in Different Contiguous Habitats? A Case Study in the Protected Habitats of the Humid Chaco Ecoregion, Northeast Argentina. Environmental Entomology. 37:419-430.

Shannon, C.E. (July and October 1948). A mathematical theory of communication. Bell System Technical Journal. 27: 379–423 and 623–656.

Sorensen, Line L. Stratification of the spider fauna in a Tanzanian rainforest. 2001. Arthropods of Tropical Forests, Cambridge University Press.

Wagner, James D., Soren Toft,and David H. Wise. 2003. Spatial Stratification in Litter Depth by Forest-Floor Spiders. Journal of Arachnology. 31:28-29.

Ziesche, Tim M. and Mechthild Roth. 2008. Influence of environmental parameters on small-scale distribution of soil-dwelling spiders in forests: What makes the difference, tree species or microhabitat? Forest Ecology and Management. 255:738-752.

- 30 - Appendices

Appendix 1: map of Misali location (Daniels et al., 2003)

Length (mm/10) and Vertical Length (mm/10) and Location Site Morphospecies Leaf # Litter Groundcover Understory #1 #2 #3 1 12 12 1 13 13 1 15 15 2 30 30 3 15 15 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11

- 31 - 3 11 11 3 11 11 3 12 12 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 19 19 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 13 13 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14

- 32 - 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 14 14 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 3 11 11 4 42 42 4 26 26 4 39 39 4 59 59 4 26 26 4 57 57 4 43 43 5 13 13 5 11 11 5 21 21 5 16 16 5 19 19 5 9 9 5 15 15 5 22 22 5 13 13 5 15 15 5 14 14 5 21 21 5 28 28 6 42 42 6 54 54 6 35 35 6 30 30 7 43 43 7 24 24 7 19 19 7 19 19 7 13 13

- 33 - 7 43 43 7 31 31 8 17 17 9 38 38 9 34 34 9 20 20 9 37 37 9 17 17 9 18 18 9 16 16 9 15 15 11 13 13 11 31 31 11 34 34 11 18 18 11 31 31 11 15 15 11 13 13 12 23 23 12 21 21 12 24 24 12 24 24 12 22 22 12 19 19 13 19 19 13 29 29 14 10 10 14 12 12 15 30 30 16 19 19 16 21 21 17 17 17 17 17 17 17 27 27 17 15 15 17 28 28 17 20 20 17 21 21 17 31 31 17 18 18 17 30 30 17 26 26 17 30 30 17 28 28 17 22 22 17 22 22 18 23 23 18 33 33

- 34 - 18 32 32 19 29 29 20 28 28 20 20 20 20 19 19 20 28 28 20 40 40 20 18 18 22 137 137 22 128 128 23 16 16 24 19 19 24 19 19 25 56 56 25 15 15 26 39 39 26 82 82 26 44 44 27 12 12 29 62 62 30 14 14 31 103 103 32 24 24 32 32 32 33 18 18 33 23 23 34 24 24 34 36 36 35 25 25 35 47 47 35 43 43 36 15 15 37 12 12 37 16 16 37 18 18 38 22 22 38 27 27 39 28 28 39 25 25 39 23 23 39 20 20 40 24 24 41 24 24 41 14 14 42 41 41 43 37 37

Appendix 2: raw data

- 35 -