Remote Cameras Reveal Experimental Artifact in a Study of Seed Predation in a Semi-Arid Shrubland

Granivorous animals may prefer to predate or cache seed of certain plant species over others. Multiple studies have documented preference for larger, non-native seed by granivores. To accomplish this, researchers have traditionally used indirect inference by relating patterns of seed removal to the species composition of the granivorous animal community. To measure seed removal, researchers present seed to granivorous animals in the field using equipment intended to exclude certain animal taxa while permitting access to others. This approach allows researchers to differentiate patterns of seed removal among various taxa (e.g., birds, small mammals, and insects); however, it is unclear whether the animals of interest are freely using the exclusion devices, which may be a hindrance to discovering the seed dishes. We used video observation to perform a study of seed predation using a custom-built, infrared digital camera and recording system. We presented native and non-native seed mixtures in partitioned Petri dishes both within and outside of exclusion cages. The exclusion cages were intended to allow entrance by rodent taxa while preventing entrance by rabbits and birds. We documented all seed removal visits by granivorous animals, which we identified to the genus level. Genera exhibited varying seed removal patterns based on seed type (native vs. non-native) and dish type (open vs. enclosed). We documented avoidance of the enclosed dishes by all but one rodent taxa, even though these dishes were intended to be used freely by rodents. This suggests that preference for non-native seed occurs differentially among granivorous animals in this system; however, interpretation of these nuanced results would be difficult without the benefit of video observation. When feasible, video observation should accompany studies using in situ equipment to ensure incorrect assumptions do not lead to inappropriate interpretation of results

An Analysis of Political Involvement Among BSN Students

This project was an initial effort to connect BSN nursing students with current legislative activity conducted by professional nursing organizations. A SWOT (Strengths Weaknesses Opportunities Threats) analysis was conducted to examine the involvement of nurses and nursing students in legislative advocacy. Strengths: As a whole, nurses are a trusted profession with a large body of members. In addition, nurses are passionate and their legislative priorities are issues that not only affect nurses, but are aimed at improving patient care as well. Weaknesses: Communication can be perceived as a challenge, which is demonstrated by nurses feeling uninformed about legislative actions currently in motion, leading them to work outside of their professional organization. Professional nursing organizations face challenges in presenting a unified voice. Opportunities: If nurses can unify through their professional organization and become politically active through the right channels, this improved professional communication would have lasting benefits. Threats: Threats to nurses and nursing students in legislative efforts include lack of experience with the intricacies and culture of politics. Recommendations: The SWOT analysis led to three recommendations for improved nurse and nursing student involvement in the legislative process: improving communication between professional organizations and its members, fostering a culture of communication and support between nursing organizations, and equipping nursing students with knowledge about the legislative process and effective ways for them to become engaged in advocacy

Remote Cameras Reveal Experimental Artifact in a Study of Seed Predation in a Semi-Arid Shrubland.

Granivorous animals may prefer to predate or cache seed of certain plant species over others. Multiple studies have documented preference for larger, non-native seed by granivores. To accomplish this, researchers have traditionally used indirect inference by relating patterns of seed removal to the species composition of the granivorous animal community. To measure seed removal, researchers present seed to granivorous animals in the field using equipment intended to exclude certain animal taxa while permitting access to others. This approach allows researchers to differentiate patterns of seed removal among various taxa (e.g., birds, small mammals, and insects); however, it is unclear whether the animals of interest are freely using the exclusion devices, which may be a hindrance to discovering the seed dishes. We used video observation to perform a study of seed predation using a custom-built, infrared digital camera and recording system. We presented native and non-native seed mixtures in partitioned Petri dishes both within and outside of exclusion cages. The exclusion cages were intended to allow entrance by rodent taxa while preventing entrance by rabbits and birds. We documented all seed removal visits by granivorous animals, which we identified to the genus level. Genera exhibited varying seed removal patterns based on seed type (native vs. non-native) and dish type (open vs. enclosed). We documented avoidance of the enclosed dishes by all but one rodent taxa, even though these dishes were intended to be used freely by rodents. This suggests that preference for non-native seed occurs differentially among granivorous animals in this system; however, interpretation of these nuanced results would be difficult without the benefit of video observation. When feasible, video observation should accompany studies using in situ equipment to ensure incorrect assumptions do not lead to inappropriate interpretation of results

Number of visits and elapsed time by seed type.

<p>Model-fitted number of seed removal visits (panel A) and elapsed time per visit (panel B) for each of three possible seed "preference" scenarios: for each visit, the granivorous animal may visit "both" sides of a partitioned Petri dish; the "non-native" side only; or the "native" side only. Although animals remove non-native seeds more than native seeds, they spend more time per visit removing native than non-native seeds.</p

Results of the highest performing model, indicated in Table 1.

<p>Parameter estimates, their standard errors, and the p-values for each effect are included. P-values less than 0.05 for interaction effects are in bold.</p

Digital camera system.

<p>The surveillance camera (A) is connected to a padded Pelican^™ case, which contains a battery supply (B) and a mini-DVR (C). The monitor (D) can be connected to the system during setup in the field to ensure the seed station is properly focused within the camera’s field of view.</p

Mass of seed removal by genus and dish type.

<p>Model-fitted seed removal (in grams) for open and enclosed dish types based on the presence of certain genera of seed predators. Although all seed predators remove more seed from open dishes, only <i>Dipodomys</i> and <i>Chaetodipus</i> visit the open dish significantly more than the enclosed dish.</p

Seed dish visitation.

<p>A nighttime picture of a visit by <i>Dipodomys</i> sp. to a seed dish. The arrow indicates the location of the partition, which separates the native and non-native seed mixtures. The rodent is visiting the open dish, and an enclosed dish is visible inside the wire mesh cage. The PVC tube, bent at a 90-degree angle, is the only entrance to the enclosed seed dish. This is meant to prohibit entrance by rabbits and birds while permitting access to rodents.</p

Mass of seed removal by seed and dish type.

<p>Model-fitted seed removal (in grams) for native and non-native seed mixtures for each dish type. We measured a greater preference for non-native seed in the open dish than in the enclosed dish.</p

Model comparisons for linear mixed-effects model using mass of seed removed as the response variable.

<p>Each model incorporated the random effect of season nested within station, and a variance structure to account for heteroscedasticity for <i>Sylvilagus</i> presence and season. Delta AIC values indicate the difference between the highest performing model and each of the competing models.</p